WO2025070307A1 - Heat sterilization device, sterilization object, and heat sterilization method - Google Patents

Abstract

This heat sterilization device 100 comprises a sterilization tank 1 that has an accommodation space 1d accommodating, in the interior thereof, a sterilization object Rp on which heat sterilization is performed using a high-temperature fluid Hth, and that is supplied with a cooling water Cw for cooling the high-temperature fluid Hth which heat-sterilizes the sterilization object Rp and the sterilization object Rp which has been heat-sterilized using the high-temperature fluid Hth. The heat sterilization device 100 also comprises a control unit that, prior to the cooling of the heat sterilization object Rp using the cooling water Cw, performs mid-temperature water heat recovery control in which heat in the sterilization tank 1 after heat sterilization is recovered using a mid-temperature water Htm that is generated separately from the high-temperature fluid Hth and has a temperature that is higher than the temperature of the cooling water Cw and lower than the temperature of the high-temperature fluid Hth.

Description

Heat sterilization device, object to be sterilized, and heat sterilization method

This invention relates to a heat sterilization device, an object to be sterilized, and a heat sterilization method.

　Conventionally, heat sterilization devices that heat sterilize objects to be sterilized are known. For example, this heat sterilization device is disclosed in JP 2000-69948 A.

The above-mentioned Japanese Patent Publication No. 2000-69948 discloses a cooking sterilization device (heat sterilization device) that heat sterilizes objects to be sterilized (objects to be sterilized).

The cooking sterilization apparatus of JP 2000-69948 A includes a sterilization tank, a hot water tank, a cold water tank, a water supply tank, a spray nozzle, a heat exchanger, and a control device (control unit). The sterilization tank contains the objects to be sterilized. The hot water tank is a tank for storing hot water to be sprayed from the spray nozzle. In order to heat sterilize the objects to be sterilized contained in the sterilization tank, the spray nozzle heats the hot water supplied from the hot water tank to a heat sterilization temperature and sprays it into the sterilization tank as a jet of water (high-temperature fluid). Here, in the cooking sterilization apparatus, after heat sterilization with the high-temperature jet of water, the hot water supplied from the hot water tank is cooled by heat exchange with water supplied from the water supply tank in the heat exchanger so that the temperature of the hot water supplied from the hot water tank is reduced to a predetermined temperature. Then, in the cooking sterilization apparatus, the hot water that has been cooled to the predetermined temperature is collected in the hot water tank. The food sterilization device is then configured to spray cooling water supplied from a cold water tank into the sterilization tank as a jet of water to cool the heated sterilized objects and the sterilization tank after thermal sterilization.

JP 2000-69948 A

However, in the cooking sterilization device of JP 2000-69948 A, the temperature of the high-temperature hot water that has been heated to the sterilization temperature is lowered by heat exchange with low-temperature cold water in the heat exchanger before it is recovered in the hot water tank. For this reason, the cooking sterilization device of JP 2000-69948 A has the problem that it takes a long time to heat the hot water (high-temperature fluid) to the sterilization temperature during the next sterilization after heat recovery.

This invention was made to solve the problems described above, and one objective of the invention is to provide a heat sterilization device, an object to be sterilized, and a heat sterilization method that can prevent the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery from increasing.

The heat sterilization device according to a first aspect of the present invention has a storage space for storing objects to be sterilized by heat sterilization using a high-temperature fluid, and is equipped with a sterilization tank to which a high-temperature fluid for heat sterilizing the objects and cooling water for cooling the objects sterilized by the high-temperature fluid are supplied, and a control unit performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water but lower than that of the high-temperature fluid before the objects to be sterilized are cooled by the cooling water.

In the heat sterilization device according to the first aspect of the present invention, as described above, a control unit is provided that performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization using medium-temperature water generated separately from the high-temperature fluid, which has a temperature higher than that of the cooling water and lower than that of the high-temperature fluid, before cooling the sterilization object with the cooling water. In this way, by performing heat recovery from the sterilization tank after heat sterilization using medium-temperature water generated separately from the high-temperature fluid, it is possible to prevent the temperature of the high-temperature fluid from decreasing, and therefore it is possible to prevent the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature from becoming long during the next heat sterilization after the heat recovery. In addition, since the sterilization tank after heat sterilization can be cooled with medium-temperature water having a temperature higher than that of the cooling water before cooling the sterilization object with the cooling water, it is possible to prevent a sudden temperature change (sudden temperature drop) in the sterilization tank after heat sterilization. As a result, the degree of expansion and contraction of the sterilization tank can be reduced, and unlike the case where large expansion and contraction are repeated, it is possible to prevent metal fatigue caused by thermal stress from increasing, and to prevent the durability of the sterilization tank from decreasing (shortening its lifespan).

In the heat sterilization device according to the first aspect, the control unit is preferably configured to perform medium temperature water heat recovery control in a state where the high temperature fluid after heat sterilization has been discharged from the sterilization tank. With this configuration, heat recovery using the high temperature fluid can be performed simply by discharging the high temperature fluid, eliminating the need for a dedicated heat exchanger and water tank for heat recovery using the high temperature fluid, thereby preventing the device from becoming larger due to heat recovery using the high temperature fluid.

The heat sterilization device according to the first aspect preferably further comprises a medium temperature water tank in which medium temperature water is stored, and the control unit is configured to perform medium temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization using medium temperature water supplied from the medium temperature water tank before cooling the object to be sterilized with cooling water, and to store the medium temperature water used for the medium temperature water heat recovery control in the medium temperature water tank. With this configuration, by storing medium temperature water in the medium temperature water tank, the medium temperature water can be easily supplied to the sterilization tank after heat sterilization during heat recovery, and by storing the medium temperature water used for heat recovery in the medium temperature water tank without discharging it, the recovered heat can be easily reused.

In this case, the control unit is preferably configured to perform preheating control to preheat the sterilization tank using the medium-temperature water heated during the medium-temperature water heat recovery control and stored in the medium-temperature water tank before heating the object to be sterilized with the high-temperature fluid. With this configuration, the initial temperature of the sterilization tank at the start of heat sterilization can be increased by preheating the sterilization tank using the medium-temperature water heated during heat recovery, so that the amount of heat given to the high-temperature fluid during heating to raise the temperature of the high-temperature fluid to the temperature for heat sterilization can be reduced compared to the case where preheating is not performed. In other words, by using medium-temperature water, the heat recovered can be effectively used for preheating. As a result, the thermal energy required in the heat sterilization device can be reduced when preheating is performed, and the amount of (high-temperature) steam used to heat the high-temperature water can be reduced accordingly.

In a heat sterilization device configured to perform preheating control to preheat the sterilization tank using medium temperature water, the control unit preferably further includes a first connection path connecting the sterilization tank and the medium temperature water tank to each other, and the control unit is configured to perform control to recover and store the medium temperature water in the sterilization tank after heat recovery in the medium temperature water tank via the first connection path, and control to supply medium temperature water to the sterilization tank via the first connection path during preheating. With this configuration, it is possible to easily store the medium temperature water after heat recovery in the medium temperature water tank, and supply medium temperature water from the medium temperature water tank to the sterilization tank during preheating, using the first connection path.

In the heat sterilization device, the control unit is preferably configured to control the discharge of medium-temperature water supplied from the medium-temperature water tank toward the object to be sterilized during each of the preheating of the sterilization tank and the heat recovery of the sterilization tank. With this configuration, when the sterilization tank is preheated, the discharged medium-temperature water is applied to the object to be sterilized to lower the temperature of the medium-temperature water, and the medium-temperature water with the lowered temperature can be applied to the sterilization tank, so that a sudden change in temperature of the low-temperature sterilization tank during preheating can be suppressed. Also, when the heat recovery of the sterilization tank is performed, the discharged medium-temperature water is applied to the object to be sterilized to raise the temperature of the medium-temperature water, and the medium-temperature water with the increased temperature can be applied to the sterilization tank, so that a sudden change in temperature of the high-temperature sterilization tank during heat recovery can be suppressed. As a result, a decrease in the durability of the sterilization tank caused by an increase in thermal stress due to a sudden change in temperature can be suppressed during each of the preheating of the sterilization tank and the heat recovery of the sterilization tank.

The heat sterilization device according to the first aspect preferably further comprises a high-temperature water tank for recovering and storing high-temperature water, which is a high-temperature fluid after heat sterilization stored in the sterilization tank, and a second connection path connecting the sterilization tank and the high-temperature water tank, and the control unit is configured to recover the high-temperature water discharged from the sterilization tank after heat sterilization of the object to be sterilized is completed into the high-temperature water tank via the second connection path, and then perform medium-temperature water heat recovery control of the sterilization tank. With this configuration, by recovering the high-temperature water in the sterilization tank via the dedicated second connection path connecting the sterilization tank and the high-temperature water tank, it is possible to prevent the heat of the high-temperature water from being taken away after heat sterilization control, and therefore it is possible to suppress a decrease in the temperature of the high-temperature water recovered in the high-temperature water tank.

The heat sterilization device having the medium temperature water tank preferably further comprises a heat transfer fluid supply unit that supplies a heat transfer fluid heated by medium temperature water, and a heat exchanger that performs heat exchange between the medium temperature water stored in the medium temperature water tank and the heat transfer fluid supplied from the heat transfer fluid supply unit, and the control unit is configured to control the supply of the heat transfer fluid, the temperature of which has been increased by heat exchange with the medium temperature water in the heat exchanger, to the sterilization tank in preheating the sterilization tank, and to control the supply of the heat transfer fluid, the temperature of which has been decreased by heat exchange with the medium temperature water in the heat exchanger, to the sterilization tank in heat recovery of the sterilization tank. With this configuration, the preheating temperature can be lowered in preheating the sterilization tank compared to when medium temperature water is directly supplied to the sterilization tank, and sudden temperature changes in the sterilization tank can be further suppressed.

The heat sterilization device according to the first aspect preferably further comprises a circulation path including a circulation pump that discharges each of the cooling water, high temperature fluid, and medium temperature water discharged from the sterilization tank and circulates them to the sterilization tank, and the control unit is configured to perform medium temperature water heat recovery control by circulating the medium temperature water to the sterilization tank via the circulation path using the circulation pump. With this configuration, the circulation path used in each of the heat sterilization control and the cooling control can be shared in the heat recovery control, thereby preventing the structure from becoming complicated and large due to an increase in the number of paths in the heat sterilization device.

　In a second aspect of the present invention, the object to be sterilized is heat sterilized by a heat sterilization device having a storage space for storing the object to be heat sterilized with a high-temperature fluid, a sterilization tank to which a high-temperature fluid for heat sterilizing the object and cooling water for cooling the object to be sterilized with the high-temperature fluid are supplied, and a control unit performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water but lower than that of the high-temperature fluid, before the object to be sterilized is cooled with the cooling water.

In the second aspect of the present invention, as described above, the sterilization object is heat-sterilized by a heat sterilization device equipped with a control unit that performs heat recovery control to recover heat from the sterilization tank after heat sterilization, using medium-temperature water that is higher than the cooling water temperature and lower than the high-temperature fluid temperature, before cooling the sterilization object with cooling water. In this way, by recovering heat from the sterilization tank after heat sterilization using medium-temperature water generated separately from the high-temperature fluid, it is possible to prevent the temperature of the high-temperature fluid from decreasing, so that it is possible to prevent the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery from being lengthened, and it is possible to provide a sterilization object that has been heat-sterilized by processing with a heat sterilization device that can prevent a decrease in the durability of the sterilization tank due to an increase in thermal stress caused by a sudden temperature change.

The heat sterilization method according to the third aspect of the present invention includes the steps of: supplying a high-temperature fluid to a sterilization tank where heat sterilization is performed with the high-temperature fluid to heat sterilize the objects to be sterilized in the sterilization tank; recovering heat from the sterilization tank after heat sterilization using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water and lower than that of the high-temperature fluid, before cooling the objects to be sterilized with cooling water; and cooling the objects to be sterilized that have been heat sterilized with cooling water after heat recovery from the sterilization tank.

In the heat sterilization method according to the third aspect of the present invention, as described above, a step is provided in which, before cooling the object to be sterilized with cooling water, heat is recovered from the sterilization tank after heat sterilization using medium-temperature water that is higher than the temperature of the cooling water and lower than the temperature of the high-temperature fluid. In this way, by recovering heat from the sterilization tank after heat sterilization using medium-temperature water generated separately from the high-temperature fluid, it is possible to prevent the temperature of the high-temperature fluid from decreasing, so that a heat sterilization method can be provided that can prevent the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery from being lengthened and that can prevent a decrease in the durability of the sterilization tank caused by an increase in thermal stress due to a sudden temperature change.

The heat sterilization method according to the third aspect preferably further comprises a step of preheating the sterilization tank using medium temperature water heated during heat recovery from the sterilization tank before supplying the high temperature fluid for heat sterilizing the object to the sterilization tank. With this configuration, the initial temperature of the sterilization tank at the start of heat sterilization can be increased by preheating the sterilization tank using medium temperature water heated during heat recovery. Therefore, compared to the case where preheating is not performed, the amount of heat given to the high temperature fluid during heating to raise the temperature of the high temperature fluid to the temperature for heat sterilization can be reduced. In other words, by using medium temperature water, the heat recovered can be effectively used for preheating. As a result, the increase in thermal energy required in the heat sterilization device when preheating is performed can be suppressed.

As described above, the present invention can prevent the time required to raise the temperature of the high-temperature fluid to the heat sterilization temperature during the next heat sterilization after heat recovery from increasing.

FIG. 1 is a schematic diagram showing a heat sterilization device of the present embodiment. FIG. 1 is a block diagram showing an overview of using heat recovered in heat recovery for a preheating step of the next heat sterilization control in the heat sterilization control of the heat sterilization device of this embodiment. 4 is a graph showing the relationship between time of heat sterilization control by the heat sterilization device of the present embodiment and temperature change in the sterilization tank. 10 is a graph showing the relationship between time of heat sterilization control by the heat sterilization device of the comparative example and temperature change in the sterilization tank. FIG. 2 is a schematic diagram showing the preparation of high-temperature water performed before the carrying-in process of the heat sterilization apparatus of the present embodiment. FIG. 2 is a schematic diagram showing preparation of medium-temperature water performed before the carrying-in process of the heat sterilization apparatus of the present embodiment. FIG. 2 is a schematic diagram showing a carrying-in process in the heat sterilization control of the heat sterilization device of the present embodiment. FIG. 8 is a schematic diagram showing a medium-temperature water injection step of a preheating step in the heat sterilization control of the heat sterilization device of this embodiment, and shows the medium-temperature water injection step following the carry-in step shown in FIG. FIG. 9 is a schematic diagram showing a medium-temperature water circulation step in the preheating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the medium-temperature water circulation step subsequent to the medium-temperature water injection step shown in FIG. FIG. 10 is a schematic diagram showing a medium-temperature water recovery step in the preheating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the medium-temperature water recovery step subsequent to the medium-temperature water circulation step shown in FIG. 11 is a schematic diagram showing a high-temperature water injection step of the object heating step in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the high-temperature water injection step following the medium-temperature water recovery step shown in FIG. 12 is a schematic diagram showing the temperature increase step and the heat sterilization step of the object heating step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the temperature increase step following the high-temperature water injection step shown in FIG. 11 . This is a schematic diagram showing a process of recovering heat by recovering high-temperature water in a high-temperature water tank in the high-temperature hydrothermal recovery process in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the high-temperature hydrothermal recovery process following the temperature rise process shown in Figure 12. 14 is a schematic diagram showing the medium-temperature water injection process of the medium-temperature water heat recovery process in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the medium-temperature water injection process following the high-temperature water heat recovery process shown in FIG. 15 is a schematic diagram showing a medium-temperature water circulation step of the medium-temperature water heat recovery step in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the medium-temperature water circulation step following the medium-temperature water injection step shown in FIG. FIG. 16 is a schematic diagram showing a medium-temperature water recovery step of the medium-temperature water heat recovery step in the heat sterilization control of the heat sterilization device of this embodiment, and shows the medium-temperature water recovery step following the medium-temperature water circulation step shown in FIG. FIG. 17 is a schematic diagram showing a cooling water injection step of the object cooling step in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the cooling water injection step following the medium-temperature water recovery step shown in FIG. FIG. 18 is a schematic diagram showing a cooling step of the object cooling step in the heat sterilization control of the heat sterilization device of the present embodiment, and shows the cooling step following the cooling water injection step shown in FIG. 17 . 19 is a schematic diagram showing a cooling water recovery step of the object cooling step in the heat sterilization control of the heat sterilization device of this embodiment, and is a diagram showing the cooling water recovery step subsequent to the cooling step shown in FIG. 18 . FIG. 2 is a schematic diagram showing a discharge process in the heat sterilization control of the heat sterilization device of the present embodiment. FIG. 11 is a graph comparing a graph of heat sterilization control by a heat sterilization device of a comparative example with a graph of heat sterilization control by the heat sterilization device of the present embodiment. 1 is a flowchart showing a heat sterilization method using the heat sterilization device of the present embodiment. FIG. 11 is a schematic diagram showing a state of an object heating process of a hot water storage type heat sterilization device of a first modified example of this embodiment. FIG. 13 is a schematic diagram showing a state of an object heating process of a steam-type heat sterilization device according to a second modified example of this embodiment. FIG. 13 is a schematic diagram showing a heat sterilization device according to a third modified example of the present embodiment.

Below, an embodiment of the present invention will be described with reference to the drawings.

The configuration of the heat sterilization device 100 according to this embodiment will be described with reference to Figures 1 to 22.

(Heat sterilization device)
As shown in Fig. 1, the heat sterilization device 100 according to the present embodiment is a spray-type device that heats a retort pouch Rp containing food by using high-temperature water Hth to heat and sterilize the food and the retort pouch Rp. The retort pouch Rp containing the food is an example of an "object to be sterilized" in the claims. The high-temperature water Hth is an example of a "high-temperature fluid" in the claims.

As shown in FIG. 1, the spray-type heat sterilization device 100 of this embodiment includes a sterilization tank 1, a spray nozzle 2, a high-temperature water tank 3, a medium-temperature water tank 4, a circulation path 5, a supply path 6, a discharge path 7, a discharge path 8, a supply path 9, a discharge path 10, a heat exchanger 11, and a control unit 12.

(Sterilization tank)
The sterilization tank 1 is a sealed container that heat-sterilizes the retort pouch Rp with high-temperature water Hth and cools the heat-sterilized retort pouch Rp with cooling water Cw. In addition, medium-temperature water Htm is supplied to the sterilization tank 1 to perform preheating and heat recovery of the retort pouch Rp. Here, the medium-temperature water Htm is water that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth. Note that the preheating and heat recovery using the medium-temperature water Htm will be described in detail later. The sterilization tank 1 includes a carry-in/out door 1a, a temperature sensor 1b, a water level sensor 1c, a storage space 1d, and a storage space 1e.

The loading/unloading door 1a is a door that is opened and closed by the user when loading and unloading trays Tr, on which multiple retort pouches Rp are placed, stacked in multiple layers into and from the sterilization tank 1. The temperature sensor 1b is a sensor for measuring the temperature inside the sterilization tank 1. The water level sensor 1c is a sensor for measuring the water levels of the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw stored in the storage space 1e. The storage space 1d is a space for storing the retort pouches Rp that are to be heat-sterilized using the high-temperature water Hth. The storage space 1e is a space for storing the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw when performing preheating, heat-sterilization, heat recovery, and cooling. The storage space 1e is a space below the lowest tray Tr of the stacked trays Tr in the storage space 1d.

(Spray nozzle)
The spray nozzle 2 in the spray-type heat sterilization device 100 according to this embodiment is configured to eject each of the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw into the sterilization tank 1. The spray nozzle 2 includes a plurality of injection ports 2a. Each of the plurality of injection ports 2a is arranged in accordance with the position of the trays Tr stacked in a plurality of stages. As a result, each of the high-temperature water Hth, the medium-temperature water Htm, and the cooling water Cw ejected from the spray nozzle 2 is ejected toward the retort pouch Rp placed on the tray Tr. A plurality of spray nozzles 2 configured in this manner are arranged in the sterilization tank 1.

(High temperature water tank)
As shown in Fig. 1, the high-temperature water tank 3 is a tank that collects and stores high-temperature water Hth, which is a high-temperature fluid after heat sterilization stored in the sterilization tank 1. The high-temperature water tank 3 has a hot water storage space capable of storing high-temperature water Hth with a volume equal to the combined volume of the storage space 1e, the circulation path 5, and the supply path 6. The high-temperature water tank 3 includes a temperature sensor 3a and a water level sensor 3b. The temperature sensor 3a is a sensor for measuring the temperature inside the high-temperature water tank 3. The water level sensor 3b is a sensor for measuring the water level of the high-temperature water Hth stored in the hot water storage space.

(Medium temperature water tank)
Here, the medium-temperature water tank 4 in this embodiment is a tank that collects and stores the medium-temperature water Htm stored in the sterilization tank 1 after preheating and after heat recovery. The medium-temperature water tank 4 has a medium-temperature water storage space capable of storing the medium-temperature water Htm with a volume equal to the combined volume of the storage space 1e, the circulation path 5, and the supply path 6. As shown in FIG. 1, the medium-temperature water tank 4 includes a temperature sensor 4a and a water level sensor 4b. The temperature sensor 4a is a sensor for measuring the temperature in the medium-temperature water tank 4. The water level sensor 4b is a sensor for measuring the water level of the medium-temperature water Htm stored in the medium-temperature water storage space.

(Circulation route)
1 , the circulation path 5 is a path that returns each of the cooling water Cw, high temperature water Hth, and medium temperature water Htm discharged from the sterilization tank 1 into the sterilization tank 1 via a heat exchanger 11. The circulation path 5 includes a discharge pipe 5a, a discharge pipe 5b, an upstream pipe 5c, a downstream pipe 5d, a temperature sensor 5e, a circulation pump 5f, and a flow path switching valve 5g.

Each of the discharge pipes 5a and 5b is a pipe for discharging the cooling water Cw, the high temperature water Hth, and the medium temperature water Htm stored in the storage space 1e. The upstream pipe 5c connects the heat exchanger 11 to each of the discharge pipes 5a and 5b. The downstream pipe 5d connects the heat exchanger 11 to the sterilization tank 1. The circulation pump 5f is a pump for discharging each of the cooling water Cw, the high temperature water Hth, and the medium temperature water Htm discharged from the sterilization tank 1 and circulating them to the sterilization tank 1. The circulation pump 5f is a pump for returning the high temperature water Hth discharged from the sterilization tank 1 to the high temperature water tank 3. The circulation pump 5f is a pump for returning the medium temperature water Htm discharged from the sterilization tank 1 to the medium temperature water tank 4. The flow path switching valve 5g is a valve for switching the flow paths through which each of the cooling water Cw, the high temperature water Hth, and the medium temperature water Htm flows.

(Supply route)
The supply path 6 is a pipeline branching off from the circulation path 5 to supply high temperature water Hth to the high temperature water tank 3. The supply path 6 is also a pipeline branching off from the circulation path 5 to supply medium temperature water Htm to the medium temperature water tank 4. The supply path 6 includes a common pipeline 6a, branch pipelines 6b, branch pipelines 6c, a flow path switching valve 6d, and a flow path switching valve 6e. The common pipeline 6a is connected to the circulation path 5 and is a common pipeline for the high temperature water tank 3 and the medium temperature water tank 4. The branch pipeline 6b branches off from the common pipeline 6a and is connected to the high temperature water tank 3. The branch pipeline 6c branches off from the common pipeline 6a and is connected to the medium temperature water tank 4.

(Excretion route)
The discharge path 7 is a pipe connecting the high temperature water tank 3 and the discharge path 8 in order to allow the high temperature water Hth in the high temperature water tank 3 to flow into the circulation path 5. The discharge path 7 includes a connecting pipe 7a and a flow path switching valve 7b. The discharge path 8 is a pipe connecting the medium temperature water tank 4 and the circulation path 5 in order to allow the medium temperature water Htm in the medium temperature water tank 4 to flow into the circulation path 5. The discharge path 8 includes a connecting pipe 8a and a flow path switching valve 8b.

Here, the circulation path 5, the common pipe 6a and the branch pipe 6c of the supply path 6, and the connection pipe 8a of the discharge path 8 are an example of a "first connection path" in the claims that connects the sterilization tank 1 and the medium-temperature water tank 4 to each other. Also, the circulation path 5, the common pipe 6a and the branch pipe 6b of the supply path 6, and the connection pipe 8a of the discharge path 8 are an example of a "second connection path" in the claims that connects the sterilization tank 1 and the high-temperature water tank 3 to each other. Also, cooling water Cw supplied from a cooling water source 200 provided in the factory in which the heat sterilization device 100 is installed flows into the circulation path 5. The cooling water Cw is supplied to a portion of the upstream pipe 5c upstream of the circulation pump 5f.

(Supply route)
The supply path 9 is a path that connects the steam inlet 301 of a boiler facility and the cooling water inlet 401 of a cooling water source, which are provided in a factory in which the heat sterilization apparatus 100 is installed, to the heat exchanger 11. The supply path 9 includes a common pipe 9a, a connection pipe 9b, a flow path switching valve 9c, and a flow path switching valve 9d.

(Excretion route)
The discharge path 10 is a path that connects the heat exchanger 11 to each of the steam drain 302 and the cooling water outlet 402, which are provided in the factory in which the heat sterilization apparatus 100 is installed. The discharge path 10 includes a common pipe 10a, a connection pipe 10b, a flow path switching valve 10c, a flow path switching valve 10d, and a steam trap 10e.

(Heat exchanger)
1 , the heat exchanger 11 is a member that heats each of the cooling water Cw and the high-temperature water Hth by exchanging heat between each of the cooling water Cw and the high-temperature water Hth flowing through the circulation path 5 and steam flowing in from the steam inlet 301. The heat exchanger 11 is a member that cools the cooling water Cw by exchanging heat between the cooling water Cw flowing through the circulation path 5 and the cooling water flowing in from the cooling water inlet 401.

(Control Unit)
The control unit 12 is configured to control the heat sterilization device 100. The control unit 12 includes a CPU (Central Processing Unit), a storage unit such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive), and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage unit stores a heat sterilization program that controls the loading and unloading of the retort pouch Rp in the heat sterilization device 100, and controls the heat sterilization, cooling, preheating, and heat recovery of the retort pouch Rp.

The control unit 12 is electrically connected to temperature sensor 1b, water level sensor 1c, temperature sensor 3a, water level sensor 3b, temperature sensor 4a, water level sensor 4b, temperature sensor 5e, circulation pump 5f, flow path switching valve 5g, flow path switching valve 6d, flow path switching valve 6e, flow path switching valve 7b, flow path switching valve 8b, flow path switching valve 9c, flow path switching valve 9d, flow path switching valve 10c, and flow path switching valve 10d. The control unit 12 is also electrically connected to not only the above-mentioned sensors, but also flow measurement sensors and pressure sensors.

The control unit 12 controls the loading and unloading of the retort pouch Rp, and controls the thermal sterilization, cooling, preheating, and heat recovery of the retort pouch Rp, based on necessary measurement information from various sensors.

(Outline of operation control of the heat sterilization device of this embodiment)
First, an overview (concept) of the operation control of the heat sterilization device 100 of this embodiment (hereinafter referred to as "heat sterilization control") will be described with reference to FIG. 2.

As shown in FIG. 2, the heat sterilization control of this embodiment includes a preheating process, an object heating process, a high-temperature water heat recovery process, a medium-temperature water heat recovery process, and an object cooling process as a series of processes. The heat sterilization control of this embodiment reduces the total amount of heat energy required when the heat sterilization control including the series of processes is performed multiple times.

Specifically, a preheating process is carried out before the object heating process, in which the low-temperature sterilization tank 1 and the retort pouch Rp (object to be sterilized) are heated. This preheating process reduces the amount of heat from the high-temperature water Hth that is taken away by the sterilization tank 1 during the object heating process, while making it easier for the high-temperature water Hth to raise the temperature of the retort pouch Rp to the heat sterilization temperature Tst at which heat sterilization is performed.

Here, in the heat sterilization control of this embodiment, as shown in FIG. 2, the medium-temperature water Htm, whose temperature has been raised (to about 90°C) by recovering heat in the medium-temperature water heat recovery process from the high-temperature sterilization tank 1 and retort pouch Rp (object to be sterilized) after heat sterilization in the first heat sterilization control, is used for preheating in the second heat sterilization control, and the temperature of the medium-temperature water Htm is reduced from about 90°C to about 50°C. Then, the heat recovered in the second heat sterilization control is used for preheating in the third control, and similar use of the recovered heat is repeated from the second control onwards.

As a result, the thermal energy required for preheating is obtained from the high-temperature sterilization tank 1 and retort pouch Rp (object to be sterilized), which would normally be discharged via the cooling water Cw in the object cooling process. This reduces the total amount of thermal energy required when performing multiple cycles of heat sterilization control including a series of processes.

(Details of Heat Sterilization Control in the Present Embodiment)
Hereinafter, details of the heat sterilization control including the preheating step and the medium-temperature water heat recovery step of this embodiment will be described with reference to Figs. 3 to 22.

As shown in FIG. 3, the heat sterilization control according to this embodiment is a control that sequentially performs a carrying-in process, a preheating process (preheating control), an object heating process (sterilization object heating sterilization control), a high-temperature water heat recovery process (high-temperature water heat recovery control), a medium-temperature water heat recovery process (medium-temperature water heat recovery control), an object cooling process (sterilization object cooling control) and a carrying-out process. The preheating process includes each of a medium-temperature water injection process, a medium-temperature water circulation process and a medium-temperature water recovery process. The object heating process includes each of a high-temperature water injection process, a temperature increase process and a heat sterilization process. The medium-temperature water heat recovery process includes each of a medium-temperature water injection process, a medium-temperature water circulation process and a medium-temperature water recovery process. The object cooling process includes each of a cooling water supply process, a cooling process and a cooling water recovery process.

In contrast to the heat sterilization control of this embodiment, which includes the above-mentioned steps, the heat sterilization control of the comparative example (corresponding to the conventional example) shown in FIG. 4 controls the retort pouch loading and unloading steps, and the retort pouch heat sterilization step, high-temperature hydrothermal heat recovery step, and cooling step. In other words, the heat sterilization device that performs the heat sterilization control of this comparative example does not have a medium temperature tank that stores medium temperature water, and does not perform preheating and heat recovery control using medium temperature water.

As described above, among the multiple steps of the heat sterilization control of this embodiment, the preheating step and the medium temperature water heat recovery step are configurations that are different from the heat sterilization control of the comparative example. These are explained in detail below.

<Preparing hot water>
First, as shown in FIG. 5, before the carrying-in step, high-temperature water Hth is prepared in advance.

Specifically, the control unit 12 performs control to form the hot water preparation circuit Ci1 by closing the flow path switching valves 5g, 6e, and 8b, and opening the flow path switching valves 6d and 7b. The control unit 12 then performs control to prepare high-temperature water Hth by heating the circulating coolant Cw through heat exchange with steam in the heat exchanger 11 while circulating the coolant Cw supplied from the cooling water source 200 through the hot water preparation circuit Ci1 using the circulation pump 5f. Here, the hot water preparation circuit Ci1 has an upstream pipe 5c, a downstream pipe 5d, a common pipe 6a, a branch pipe 6b, a connecting pipe 7a, and a connecting pipe 8a. In the hot water preparation circuit Ci1, the cooling water Cw flows in the following order: connecting line 7a, connecting line 8a, upstream line 5c, downstream line 5d, common line 6a, and branch line 6b.

<Preparing medium temperature water>
Furthermore, as shown in FIG. 6, before the carrying-in step, the medium-temperature water Htm is prepared in advance.

Specifically, after preparing high-temperature water Hth, the control unit 12 closes flow path switching valves 5g, 6d, and 7b, and opens flow path switching valves 6e and 8b, thereby forming a medium-temperature water preparation circuit Ci2. The control unit 12 then circulates cooling water Cw supplied from the cooling water source 200 through the medium-temperature water preparation circuit Ci2 using the circulation pump 5f, while heating the circulating cooling water Cw through heat exchange with steam in the heat exchanger 11, thereby preparing medium-temperature water Htm (approximately 90°C). Here, the medium-temperature water preparation circuit Ci2 has an upstream pipe 5c, a downstream pipe 5d, a common pipe 6a, a branch pipe 6c, and a connecting pipe 8a. In the medium-temperature water preparation circuit Ci2, the cooling water Cw flows in the following order: connecting line 8a, upstream line 5c, downstream line 5d, common line 6a, and branch line 6c.

<Delivery process>
7, after the medium-temperature water Htm and the high-temperature water Hth are prepared, a carrying-in process is performed. In the carrying-in process, trays Tr on which a plurality of retort pouches Rp are placed are carried into the sterilization tank 1 by a user in a state of being stacked in multiple stages.

<Preheating process>
As shown in Fig. 8, before the heat sterilization of the retort pouch Rp with high-temperature water Hth, the control unit 12 performs control to preheat the sterilization tank 1 and the retort pouch Rp using medium-temperature water Htm supplied from the medium-temperature water tank 4. As a result, the sterilization tank 1 is preheated with the medium-temperature water Htm before the high-temperature water Hth is injected into the sterilization tank 1, so that a sudden temperature change Tch1 (see the comparative example in Fig. 4) in the sterilization tank 1 is suppressed.

Specifically, the control unit 12 performs control to form the medium-temperature water injection path Sp1 by closing the flow path switching valves 6d, 6e, and 7b, and opening the flow path switching valves 5g and 8b. The control unit 12 then performs control to inject the medium-temperature water Htm in the medium-temperature water tank 4 into the sterilization tank 1 via the medium-temperature water injection path Sp1 using the circulation pump 5f (medium-temperature water injection process (see FIG. 3)). Here, the medium-temperature water injection path Sp1 has an upstream pipe 5c, a downstream pipe 5d, and a connecting pipe 8a. In the medium-temperature water injection path Sp1, the medium-temperature water Htm flows in the order of the connecting pipe 8a, the upstream pipe 5c, and the downstream pipe 5d.

In this way, the control unit 12 controls the supply of medium-temperature water Htm to the sterilization tank 1 via the upstream pipe 5c, the downstream pipe 5d, and the connecting pipe 8a during preheating.

As shown in FIG. 9, after injecting the medium-temperature water Htm, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby forming the medium-temperature water circulation path Ci3. The control unit 12 then performs preheating control by circulating the medium-temperature water Htm to the sterilization tank 1 through the medium-temperature water circulation path Ci3 using the circulation pump 5f without heat exchange in the heat exchanger 11 (medium-temperature water circulation process (see FIG. 3)). Here, the medium-temperature water circulation path Ci3 has a circulation route 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the medium-temperature water circulation path Ci3, the medium-temperature water Htm flows in the order of the discharge pipes 5a and 5b, the upstream pipe 5c, and the downstream pipe 5d.

At this time, the control unit 12 controls the discharge of the medium-temperature water Htm supplied from the medium-temperature water tank 4 toward the retort pouch Rp during the preheating of the sterilization tank 1. Here, during the preheating process, the temperature of the medium-temperature water Htm has dropped to the post-preheating temperature (approximately 50°C) by applying heat to the sterilization tank 1 and the retort pouch Rp.

As shown in FIG. 10, the control unit 12 circulates the medium-temperature water Htm for a predetermined time, and then controls the medium-temperature water Htm in the preheated sterilization tank 1 to be collected and stored in the medium-temperature water tank 4 via the medium-temperature water collection passage Re1.

Specifically, the control unit 12 circulates the medium temperature water Htm for a predetermined time, and then closes flow path switching valves 5g, 6d, 7b, and 8b, and opens flow path switching valve 6e, thereby forming a medium temperature water recovery path Re1. Then, the control unit 12 performs recovery control to recover the medium temperature water Htm into the medium temperature water tank 4 via the medium temperature water recovery path Re1 using the circulation pump 5f (medium temperature water recovery process (see Figure 3)). Here, the medium temperature water recovery path Re1 has discharge pipeline 5a, discharge pipeline 5b, upstream pipeline 5c, downstream pipeline 5d, common pipeline 6a, and branch pipeline 6c. In the medium-temperature water recovery line Re1, the medium-temperature water Htm flows in the order of the discharge pipes 5a and 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6c.

Then, the control unit 12 recovers the medium-temperature water Htm in the sterilization tank 1 into the medium-temperature water tank 4 via the medium-temperature water recovery passage Re1, and then performs the object heating process for the retort pouch Rp. At this time, the water level sensor 1c confirms that the medium-temperature water Htm has been discharged from the sterilization tank 1, thereby preventing the temperature of the high-temperature water Hth from decreasing due to the medium-temperature water Htm.

<Object heating process>
As shown in Figures 11 and 12, the control unit 12 performs control to preheat the retort pouch Rp with medium-temperature water Htm and then heat-sterilize the retort pouch Rp using high-temperature water Hth supplied from the high-temperature water tank 3.

Specifically, as shown in FIG. 11, the control unit 12 performs control to form the hot water injection path Sp2 by closing the flow path switching valves 6d, 6e, and 8b, and opening the flow path switching valves 5g and 7b. The control unit 12 then performs control to inject the medium-temperature water Htm in the high-temperature water tank 3 into the sterilization tank 1 via the hot water injection path Sp2 using the circulation pump 5f (high-temperature water injection process (see FIG. 3)). Here, the hot water injection path Sp2 has an upstream pipe 5c, a downstream pipe 5d, a connecting pipe 7a, and a connecting pipe 8a. In the hot water injection path Sp2, the high-temperature water Hth flows in the order of the connecting pipe 7a, the connecting pipe 8a, the upstream pipe 5c, and the downstream pipe 5d.

12, after injecting high-temperature water Hth, the control unit 12 closes flow path switching valves 6d, 6e, 7b, and 8b, and opens flow path switching valve 5g, thereby forming a temperature-raising and heat-sterilizing circuit Ci4. The control unit 12 then performs temperature-raising control to raise the temperature of the high-temperature water Hth to a heat-sterilizing temperature Tst (for example, higher than about 120°C) by heat exchange with steam in the heat exchanger 11, while circulating the high-temperature water Hth to the sterilization tank 1 through the temperature-raising and heat-sterilizing circuit Ci4 using the circulation pump 5f (temperature-raising process (see FIG. 3)). Here, the temperature-raising and heat-sterilizing circuit Ci4 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the temperature-raising/heat-sterilization circulation path Ci4, high-temperature water Hth flows through each of the discharge pipes 5a and 5b, the upstream pipe 5c, and the downstream pipe 5d in that order. Note that the heat-sterilization temperature Tst being higher than about 120°C is merely an example, and varies depending on the type of material to be heat-sterilized.

In addition, the control unit 12 heats the high-temperature water Hth up to the heat sterilization temperature Tst, and then circulates the high-temperature water Hth to the sterilization tank 1 via the temperature-raising and heat sterilization circulation path Ci4 using the circulation pump 5f, while performing heat sterilization control to maintain the high-temperature water Hth at the heat sterilization temperature Tst through heat exchange with steam in the heat exchanger 11 (heat sterilization process).

<High-temperature water heat recovery process>
As shown in Fig. 13, the control unit 12 performs control for a predetermined time after heat sterilization with high-temperature water Hth to recover and store the high-temperature water Hth in the sterilization tank 1 after heat sterilization via the hot water recovery passage Re2 in the high-temperature water tank 3. The high-temperature hydrothermal recovery process is a process of recovering the high-temperature water Hth in the high-temperature water tank 3 while maintaining the temperature after heat sterilization.

Specifically, after heat sterilization with high-temperature water Hth for a predetermined time, the control unit 12 closes the flow path switching valves 5g, 6e, 7b, and 8b, and opens the flow path switching valve 6d, thereby forming the hot water recovery line Re2. The control unit 12 then performs recovery control to recover the high-temperature water Hth to the high-temperature water tank 3 via the hot water recovery line Re2 using the circulation pump 5f (high-temperature water heat recovery process (see FIG. 3)). Here, the hot water recovery line Re2 has the discharge line 5a, the discharge line 5b, the upstream line 5c, the downstream line 5d, the common line 6a, and the branch line 6b. In the hot water recovery line Re2, the high-temperature water Hth flows in the order of the discharge line 5a and the discharge line 5b, the upstream line 5c, the downstream line 5d, the common line 6a, and the branch line 6b.

Then, the control unit 12 recovers the high-temperature water Hth discharged from the sterilization tank 1 into the high-temperature water tank 3 via the hot water recovery passage Re2, and then performs a medium-temperature water heat recovery process for the sterilization tank 1 and the retort pouch Rp. That is, the control unit 12 controls the medium-temperature water heat recovery process in a state in which the high-temperature water Hth after heat sterilization is discharged from the sterilization tank 1. At this time, the water level sensor 1c confirms that the high-temperature water Hth has been discharged from the sterilization tank 1, thereby preventing the temperature of the medium-temperature water Htm from rising due to the high-temperature water Hth.

<Medium-temperature water heat recovery process>
14 to 16, before cooling the retort pouch Rp with the cooling water Cw, the control unit 12 performs a medium-temperature water heat recovery step of recovering heat from the sterilization tank 1 and the retort pouch Rp using medium-temperature water Htm supplied from the medium-temperature water tank 4. As a result, heat from the sterilization tank 1 is recovered by the medium-temperature water Htm before the cooling water Cw is injected into the sterilization tank 1, so that a sudden temperature change Tch2 in the sterilization tank 1 (see the comparative example in FIG. 4) is suppressed.

Specifically, as shown in FIG. 14, the control unit 12 performs control to form the medium-temperature water injection path Sp3 by closing the flow path switching valves 6d, 7b, and 6e, and opening the flow path switching valves 5g and 8b. The control unit 12 then performs control to inject the medium-temperature water Htm in the medium-temperature water tank 4 into the sterilization tank 1 via the medium-temperature water injection path Sp3 using the circulation pump 5f (medium-temperature water injection process (see FIG. 3)). Here, the medium-temperature water injection path Sp3 has an upstream pipe 5c, a downstream pipe 5d, and a connecting pipe 8a. In the medium-temperature water injection path Sp3, the medium-temperature water Htm flows in the order of the connecting pipe 8a, the upstream pipe 5c, and the downstream pipe 5d.

As shown in FIG. 15, after injecting the medium-temperature water Htm, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby forming the heat recovery circuit Ci5. The control unit 12 then performs medium-temperature water heat recovery control by circulating the medium-temperature water Htm to the sterilization tank 1 through the heat recovery circuit Ci5 by the circulation pump 5f without heat exchange in the heat exchanger 11 (medium-temperature water circulation process (see FIG. 3)). Here, the heat recovery circuit Ci5 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the heat recovery circuit Ci5, the medium-temperature water Htm flows in the order of the discharge pipes 5a and 5b, the upstream pipe 5c, and the downstream pipe 5d.

At this time, the control unit 12 controls the medium-temperature water Htm supplied from the medium-temperature water tank 4 to be discharged toward the retort pouch Rp during heat recovery in the sterilization tank 1. Here, during the medium-temperature water circulation process, the temperature of the medium-temperature water Htm rises to the post-heat recovery temperature (approximately 90°C) by removing heat from the sterilization tank 1 and the retort pouch Rp, etc.

As shown in FIG. 16, the control unit 12 circulates the medium-temperature water Htm for a predetermined time, and then controls the medium-temperature water Htm in the sterilization tank 1 after heat recovery to be recovered and stored in the medium-temperature water tank 4 via the medium-temperature water recovery passage Re3.

Specifically, the control unit 12 circulates the medium temperature water Htm for a predetermined time, and then closes flow path switching valves 5g, 6d, 7b, and 8b, and opens flow path switching valve 6e, thereby forming a medium temperature water recovery path Re3. Then, the control unit 12 performs recovery control to recover the medium temperature water Htm into the medium temperature water tank 4 via the medium temperature water recovery path Re3 using the circulation pump 5f (medium temperature water recovery process (see Figure 3)). Here, the medium temperature water recovery path Re3 has discharge pipeline 5a, discharge pipeline 5b, upstream pipeline 5c, downstream pipeline 5d, common pipeline 6a, and branch pipeline 6c. In the medium-temperature water recovery line Re3, the medium-temperature water Htm flows in the order of the discharge pipes 5a and 5b, the upstream pipe 5c, the downstream pipe 5d, the common pipe 6a, and the branch pipe 6c.

In this way, the control unit 12 performs a medium-temperature water heat recovery process to recover heat from the sterilization tank 1 after thermal sterilization using the medium-temperature water Htm supplied from the medium-temperature water tank 4 before the process of cooling the object in the retort pouch Rp with the cooling water Cw, and controls the medium-temperature water Htm used in the medium-temperature water heat recovery process to be stored in the medium-temperature water tank 4. In other words, the control unit 12 controls the medium-temperature water Htm in the sterilization tank 1 after heat recovery to be recovered and stored in the medium-temperature water tank 4 via the discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, downstream pipe 5d, common pipe 6a, and branch pipe 6c.

Then, the control unit 12 recovers the medium-temperature water Htm in the sterilization tank 1 into the medium-temperature water tank 4 via the medium-temperature water recovery passage Re3, and then performs a cooling process for the retort pouch Rp. At this time, the water level sensor 1c confirms that the medium-temperature water Htm has been discharged from the sterilization tank 1, thereby preventing the temperature of the cooling water Cw from increasing due to the medium-temperature water Htm.

<Object cooling process>
As shown in Figures 17 to 19, after heat recovery of the retort pouch Rp by the medium-temperature water Htm, the control unit 12 performs a cooling process to cool the retort pouch Rp and the sterilization tank 1 using cooling water Cw supplied from the cooling water source 200 (see Figure 1).

Specifically, as shown in FIG. 17, the control unit 12 performs control to form the cooling water injection passage Sp4 by closing the flow path switching valves 6d, 6e, 7b, and 8b and opening the flow path switching valve 5g. The control unit 12 then performs control to inject the cooling water Cw supplied from the cooling water source 200 by the circulation pump 5f through the cooling water injection passage Sp4 into the sterilization tank 1 (cooling water injection process (see FIG. 3)). Here, the cooling water injection passage Sp4 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the cooling water injection passage Sp4, the cooling water Cw flows in the order of the upstream pipe 5c, downstream pipe 5d, discharge pipe 5a, and discharge pipe 5b.

18, after injecting the cooling water Cw, the control unit 12 closes the flow path switching valves 6d, 6e, 7b, and 8b, and opens the flow path switching valve 5g, thereby forming the cooling circuit Ci6. The control unit 12 then performs cooling control to cool the cooling water Cw, which has been heated by removing heat from the retort pouch Rp and the sterilization tank 1 through heat exchange with the cooling water in the heat exchanger 11, while circulating the cooling water Cw through the cooling circuit Ci6 by the circulation pump 5f (cooling process (see FIG. 3)). Here, the cooling circuit Ci6 has a circulation path 5 (discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, and downstream pipe 5d). In the cooling circuit Ci6, the cooling water Cw flows through the discharge pipes 5a and 5b, the upstream pipe 5c, and the downstream pipe 5d in that order.

As shown in FIG. 19, after cooling with cooling water Cw for a predetermined time, the control unit 12 controls the circulation pump 5f to recover the cooling water Cw in the sterilization tank 1 after cooling through the cooling water recovery line Re4 (cooling water recovery process). Here, the cooling water recovery line Re4 has discharge pipes 5a, 5b, and an upstream pipe 5c. In the cooling water recovery line Re4, the cooling water Cw flows through each of the discharge pipes 5a and 5b, and then through the upstream pipe 5c, in that order.

<Removal process>
In the carrying-out step, as shown in FIG. 20, a plurality of cooled retort pouches Rp are carried out of the sterilization tank 1 by the user.

Then, the next heat sterilization control is performed on the multiple retort pouches Rp. At this time, the control unit 12 performs a preheating process to preheat the sterilization tank 1 using the medium-temperature water Htm that was heated during the medium-temperature water heat recovery process (medium-temperature water heat recovery control) and stored in the medium-temperature water tank 4 before heating the retort pouches Rp with the high-temperature water Hth. As a result, in the heat sterilization control of this embodiment, the heat taken from the retort pouches Rp and the sterilization tank 1, etc. during the medium-temperature water heat recovery process is used, so the occurrence of heat loss is suppressed. In addition, since only a slight re-heating (for example, about 1 to 2°C) is required during the advance preparation of the medium-temperature water Htm shown in FIG. 6, the amount of heat required to heat the medium-temperature water Htm and the time required to heat the medium-temperature water Htm are suppressed after the first heat sterilization control.

Such heat sterilization control is performed multiple times a day. The medium-temperature water Htm stored in the medium-temperature water tank 4 is reused and then discharged from the medium-temperature water tank 4. Then, control is performed to store new medium-temperature water Htm in the medium-temperature water tank 4 (see FIG. 6). The timing for replacing such medium-temperature water Htm is once a day or once every few days, and is set appropriately by the user. This suppresses the increase in water usage caused by using medium-temperature water Htm, compared to when medium-temperature water Htm is prepared for each heating control.

(Comparison between heat sterilization control of the comparative example and heat sterilization control of the present embodiment)
Fig. 21 shows a graph in which the graph of the heat sterilization control of the comparative example (corresponding to the conventional example) shown in Fig. 4 and the graph of the heat sterilization control of the present embodiment shown in Fig. 3 are superimposed. Here, the graph of the heat sterilization control of the comparative example is shown by a thick two-dot chain line. Also, the graph of the heat sterilization control of the present embodiment is shown by a thick solid line.

Comparing the heat sterilization control of the comparative example with the heat sterilization control of this embodiment, the operation time of the heat sterilization control of the embodiment increases by time Tlag because a preheating process and a medium temperature water heat recovery process are added.

However, the time Ui of the temperature increase process of the object heating process in the heat sterilization control of this embodiment is shorter than the time Ue of the temperature increase process of the object heating process in the heat sterilization control of the comparative example. This is because, in the heat sterilization control of this embodiment, the initial temperature of the object heating process is higher due to the preheating process than the initial temperature of the object heating process in the heat sterilization control of the comparative example. Furthermore, the time Di of the object cooling process in the heat sterilization control of this embodiment is shorter than the time De of the object cooling process in the heat sterilization control of the comparative example. This is because, in the heat sterilization control of this embodiment, the initial temperature of the object cooling process is lower due to the medium-temperature water heat recovery process than the initial temperature of the object cooling process in the heat sterilization control of the comparative example.

In addition, by making the time Ui of the temperature rise process shorter than the time Ue of the temperature rise process, the amount of steam required to raise the temperature of the high-temperature water Hth is reduced. In addition, in the advance preparation of the medium-temperature water Htm, the medium-temperature water Htm is heated with steam, but due to the reuse of the medium-temperature water Htm and the reduction in the amount of steam required to raise the temperature of the high-temperature water Hth, when heat sterilization control is performed multiple times, the thermal energy required for heat sterilization control is reduced compared to when the heat sterilization control of the comparative example is performed multiple times.

Furthermore, in the heat sterilization control of this embodiment, since medium temperature water Htm is injected into the sterilization tank 1 after the carry-in process, the temperature change Ti1 of the sterilization tank 1 after the carry-in process is smaller by the temperature difference Td1 than the temperature change Te1 of the sterilization tank 1 after the carry-in process in the comparative example. Furthermore, in the heat sterilization control, since medium temperature water Htm is injected into the sterilization tank 1 after the high temperature hydrothermal recovery process, the temperature change Ti2 of the sterilization tank 1 after the high temperature hydrothermal recovery process is smaller by the temperature difference Td2 than the temperature change Te2 of the sterilization tank 1 after the carry-in process in the comparative example. This suppresses sudden temperature changes in the sterilization tank 1, thereby suppressing expansion and contraction of the sterilization tank 1.

(Heat sterilization method)
A heat sterilization method performed in the above-mentioned heat sterilization device 100 will be described with reference to Figures 7, 9, 12, 15, 18, 20 and 22. The heat sterilization method is a method executed by the control unit 12 based on a heat sterilization program.

Here, high-temperature water Hth and medium-temperature water Htm are prepared prior to the preheating process of step S1 shown in FIG. 22. Here, in the following explanation, it is assumed that the medium-temperature water Htm is heated during the above-mentioned medium-temperature water heat recovery process (medium-temperature water heat recovery control) and stored in the medium-temperature water tank 4. Then, a loading process is performed in which trays Tr on which multiple retort pouches Rp are placed are loaded into the sterilization tank 1 by the user in a stacked state (see FIG. 7).

In step S1 shown in FIG. 22, a preheating process is carried out after the carrying-in process. The preheating process is a process in which the sterilization tank 1 is preheated using medium-temperature water Htm heated during heat recovery from the sterilization tank 1 before high-temperature water Hth for heat sterilizing the retort pouch Rp is supplied to the sterilization tank 1 (see FIG. 9).

In step S2, the object heating process is performed. The object heating process is a process in which high-temperature water Hth is supplied to the sterilization tank 1, where the heat sterilization is performed using high-temperature water Hth, to heat sterilize the retort pouch Rp in the sterilization tank 1 (see FIG. 12).

In step S3, a high-temperature hydrothermal recovery process is carried out. The high-temperature hydrothermal recovery process is a process in which, after heat sterilization using high-temperature water Hth, the high-temperature water Hth in the sterilization tank 1 after heat sterilization is recovered and stored in the high-temperature water tank 3 via the hot water recovery passage Re2 (see FIG. 13).

In step S4, a medium-temperature water heat recovery process is carried out. The medium-temperature water heat recovery process is a process for recovering heat from the sterilization tank 1 after thermal sterilization, using medium-temperature water Htm that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw but lower than that of the high-temperature water Hth, before cooling the retort pouch Rp with the cooling water Cw (see FIG. 15).

In step S5, the object cooling process is carried out. The object cooling process is a process in which the retort pouch Rp that has been heat-sterilized is cooled with cooling water Cw after heat recovery in the sterilization tank 1 (see FIG. 18). Then, after step S5, the heat sterilization method ends.

After the heat sterilization method is completed, the user performs the unloading process to unload the cooled retort pouch Rp from the sterilization tank 1 (see Figure 20).

(retort pouch)
The retort pouch Rp produced by such a heat sterilization bath method is subjected to heat sterilization treatment by a heat sterilization device 100.

Specifically, the retort pouch Rp (object to be sterilized) is heat sterilized by a heat sterilization device 100 having a storage space 1d for storing the retort pouch Rp (object to be sterilized) to be heat sterilized with high-temperature water Hth (high-temperature fluid), a sterilization tank 1 to which high-temperature water Hth (high-temperature fluid) for heat sterilizing the retort pouch Rp (object to be sterilized) and cooling water Cw for cooling the retort pouch Rp (object to be sterilized) that has been heat sterilized with the high-temperature water Hth (high-temperature fluid) are supplied, and a control unit 12 for performing medium-temperature water heat recovery control to recover heat from the sterilization tank 1 after heat sterilization using medium-temperature water Htm that is generated separately from the high-temperature water Hth (high-temperature fluid) and has a temperature higher than the cooling water Cw and lower than the temperature of the high-temperature water Hth (high-temperature fluid) before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw.

(Effects of this embodiment)
In this embodiment, the following effects can be obtained.

In this embodiment, as described above, the heat sterilization device 100 is equipped with a control unit 12 that performs a medium temperature water heat recovery process (medium temperature water heat recovery control) to recover heat from the sterilization tank 1 after the object heating process (heat sterilization control) using medium temperature water Htm generated separately from the high temperature water Hth, the medium temperature water Htm having a temperature higher than the cooling water Cw and lower than the temperature of the high temperature water Hth, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw. In this way, by using the medium temperature water Htm generated separately from the high temperature water Hth to recover heat from the sterilization tank 1 after heat sterilization, it is possible to prevent the temperature of the high temperature water Hth from decreasing, and therefore it is possible to prevent the time required to raise the temperature of the high temperature water Hth to the heat sterilization temperature Tst from becoming long during the next heat sterilization after heat recovery. In addition, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw, the sterilization tank 1 after the object heating step (heat sterilization control) can be cooled with medium-temperature water Htm having a temperature higher than that of the cooling water Cw, so that a sudden change in temperature (a sudden drop in temperature) in the sterilization tank 1 after the object heating step (heat sterilization control) can be suppressed. As a result, the degree of expansion and contraction of the sterilization tank 1 can be reduced, and unlike the case where large expansion and contraction are repeated, the increase in metal fatigue due to thermal stress can be suppressed, and the decrease in durability (shortening of life) of the sterilization tank 1 can be suppressed.

In addition, in this embodiment, as described above, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw, the control unit 12 performs a medium-temperature water heat recovery process (medium-temperature water heat recovery control) to recover heat from the sterilization tank 1 after the object heating process (heat sterilization control) using medium-temperature water Htm that is generated separately from the high-temperature water Hth and has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth. As a result, by recovering the heat from the sterilization tank 1 after the object heating process (heat sterilization control) using the medium-temperature water Htm in the medium-temperature water heat recovery process (medium-temperature water heat recovery control), it is possible to suppress heat loss of the heat given to the retort pouch Rp and the sterilization tank 1 during the object heating process (heat sterilization control).

In addition, in this embodiment, as described above, the control unit 12 performs a medium temperature water heat recovery process (medium temperature water heat recovery control) in a state where the high temperature water Hth after heat sterilization is discharged from the sterilization tank 1. As a result, heat recovery using high temperature water Hth is performed simply by discharging the high temperature water Hth, and therefore a dedicated heat exchanger and water supply tank for heat recovery using high temperature water Hth are not required, and it is possible to suppress an increase in size of the device due to heat recovery using high temperature water Hth.

In addition, in this embodiment, as described above, the heat sterilization device 100 is equipped with the medium-temperature water tank 4 in which the medium-temperature water Htm is stored. The control unit 12 is configured to perform a medium-temperature water heat recovery process (medium-temperature water heat recovery control) that recovers heat from the sterilization tank 1 after heat sterilization using the medium-temperature water Htm supplied from the medium-temperature water tank 4 before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw, and to store the medium-temperature water Htm used in the medium-temperature water heat recovery process (medium-temperature water heat recovery control) in the medium-temperature water tank 4. As a result, by storing the medium-temperature water Htm in the medium-temperature water tank 4, the medium-temperature water Htm can be easily supplied to the sterilization tank 1 after heat sterilization during heat recovery, and by storing the medium-temperature water Htm used for heat recovery in the medium-temperature water tank 4 without discharging it, the recovered heat can be easily reused.

In addition, in this embodiment, as described above, the control unit 12 performs a preheating process (preheating control) to preheat the sterilization tank 1 using the medium-temperature water Htm heated during the medium-temperature water heat recovery process (medium-temperature water heat recovery control) and stored in the medium-temperature water tank 4 before heating the retort pouch Rp (object to be sterilized) with the high-temperature water Hth. As a result, by preheating the sterilization tank 1 using the heated medium-temperature water Htm used for heat recovery, the initial temperature of the sterilization tank 1 at the start of the object heating process (heat sterilization control) can be increased, so that the amount of heat given to the high-temperature water Hth during the temperature increase to increase the temperature of the high-temperature water Hth to the temperature at which the object heating process (heat sterilization control) is performed can be reduced compared to the case where preheating is not performed. In other words, by using the medium-temperature water Htm, the heat recovered can be effectively used for preheating. As a result, the increase in thermal energy required in the heat sterilization device 100 when preheating is performed can be reduced, and the amount of (high-temperature) steam used to increase the temperature of the high-temperature water Hth can be reduced accordingly.

In addition, in this embodiment, as described above, the heat sterilization device 100 includes the circulation path 5, common pipe 6a, branch pipe 6c, and connection pipe 8a (first connection path) that connect the sterilization tank 1 and the medium-temperature water tank 4 to each other. The control unit 12 controls the recovery and storage of the medium-temperature water Htm in the sterilization tank 1 after heat recovery in the medium-temperature water tank 4 via the discharge pipe 5a, discharge pipe 5b, upstream pipe 5c, downstream pipe 5d, common pipe 6a, and branch pipe 6c (first connection path), and controls the supply of medium-temperature water Htm to the sterilization tank 1 via the upstream pipe 5c, downstream pipe 5d, and connection pipe 8a (first connection path) during preheating. This makes it easy to use the common pipe 6a and the branch pipe 6c (first connection path) to store the medium-temperature water Htm after heat recovery in the medium-temperature water tank 4, and to supply the medium-temperature water Htm during preheating from the medium-temperature water tank 4 to the sterilization tank 1.

In addition, in this embodiment, as described above, the control unit 12 controls the release of the medium-temperature water Htm supplied from the medium-temperature water tank 4 toward the retort pouch Rp (object to be sterilized) during each of the preheating of the sterilization tank 1 and the heat recovery of the sterilization tank 1. As a result, when the low-temperature sterilization tank 1 is preheated, the temperature of the medium-temperature water Htm is lowered by applying the released medium-temperature water Htm to the retort pouch Rp (object to be sterilized), and the medium-temperature water Htm with a lowered temperature can be applied to the sterilization tank 1, so that a sudden change in temperature of the sterilization tank 1 can be suppressed. Also, during heat recovery of the sterilization tank 1, the temperature of the medium-temperature water Htm is raised by applying the released medium-temperature water Htm to the retort pouch Rp (object to be sterilized), and the high-temperature sterilization tank 1 during heat recovery can be applied with the medium-temperature water Htm with a higher temperature, so that a sudden change in temperature of the sterilization tank 1 can be suppressed. As a result, in both preheating the sterilization tank 1 and heat recovery from the sterilization tank 1, it is possible to further suppress the deterioration of the durability of the sterilization tank 1 caused by increased thermal stress due to sudden temperature changes.

Furthermore, in this embodiment, as described above, the heat sterilization device 100 is provided with a high-temperature water tank 3 that collects and stores high-temperature water Hth, which is high-temperature water Hth stored in the sterilization tank 1 after the object heating process (heat sterilization control). The heat sterilization device 100 is provided with a common pipe 6a and a branch pipe 6b (second connection path) that connect the sterilization tank 1 and the high-temperature water tank 3 to each other. The control unit 12 collects the high-temperature water Hth discharged from the sterilization tank 1 after the object heating process (heat sterilization control) of the retort pouch Rp (sterilization object) is completed into the high-temperature water tank 3 via the common pipe 6a and the branch pipe 6b (second connection path), and then performs a medium-temperature water heat recovery process (medium-temperature water heat recovery control) of the sterilization tank 1. As a result, by recovering the high-temperature water Hth in the sterilization tank 1 through a dedicated common pipe 6a and a branch pipe 6b (second connection path) that connect the sterilization tank 1 and the high-temperature water tank 3 to each other, it is possible to prevent the heat of the high-temperature water Hth from being lost after the object heating process (heat sterilization control), and therefore it is possible to suppress a decrease in the temperature of the high-temperature water Hth recovered in the high-temperature water tank 3.

In addition, in this embodiment, as described above, the heat sterilization device 100 is provided with a circulation path 5 including a circulation pump 5f that discharges each of the cooling water Cw, high-temperature water Hth, and medium-temperature water Htm discharged from the sterilization tank 1 and circulates them to the sterilization tank 1. The control unit 12 performs a medium-temperature water heat recovery process (medium-temperature water heat recovery control) by circulating the medium-temperature water Htm to the sterilization tank 1 via the circulation path 5 using the circulation pump 5f. This allows the circulation path 5 used in each of the object heating process (heat sterilization control) and the object cooling process (cooling control) to be commonly used in the medium-temperature water heat recovery process (medium-temperature water heat recovery control), thereby preventing the structure from becoming complicated and large due to an increase in the number of paths in the heat sterilization device 100.

In addition, in this embodiment, as described above, the retort pouch Rp (object to be sterilized) is heat sterilized by a heat sterilization device 100 having a storage space 1d for storing the retort pouch Rp (object to be sterilized) therein, which is to be heat sterilized using high-temperature water Hth, a sterilization tank 1 to which high-temperature water Hth for performing an object heating process (heat sterilization control) on the object to be sterilized and cooling water Cw for cooling the retort pouch Rp (object to be sterilized) which has been subjected to the object heating process (heat sterilization control) using the high-temperature water Hth, and a control unit 12 for performing a medium-temperature water heat recovery process (medium-temperature water heat recovery control) for recovering heat from the sterilization tank 1 after the object heating process (heat sterilization control) using medium-temperature water Htm which is generated separately from the high-temperature water Hth and has a temperature higher than the cooling water Cw and lower than the temperature of the high-temperature water Hth, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw. As a result, by using the medium temperature water Htm generated separately from the high temperature water Hth to recover heat from the sterilization tank 1 after heat sterilization, it is possible to prevent the temperature of the high temperature water Hth from decreasing, so that it is possible to prevent the time required to raise the temperature of the high temperature water Hth to the heat sterilization temperature Tst during the next heat sterilization after heat recovery from being lengthened, and it is possible to provide a retort pouch Rp (object to be sterilized) that has been heat sterilized by the heat sterilization device 100, which can prevent a decrease in the durability of the sterilization tank 1 due to an increase in thermal stress caused by a sudden temperature change.

In addition, in this embodiment, as described above, the heat sterilization method includes step S4 of recovering heat from the sterilization tank 1 after the object heating step (heat sterilization control) using medium-temperature water Htm generated separately from the high-temperature water Hth, which has a temperature higher than that of the cooling water Cw and lower than that of the high-temperature water Hth, before cooling the retort pouch Rp (object to be sterilized) with the cooling water Cw. As a result, by recovering heat from the sterilization tank 1 after heat sterilization using medium-temperature water Htm generated separately from the high-temperature water Hth, it is possible to prevent the temperature of the high-temperature water Hth from decreasing, so that it is possible to prevent the time required to heat the high-temperature water Hth to the heat sterilization temperature Tst from becoming long during the next heat sterilization after heat recovery, and it is possible to provide a heat sterilization method that can prevent a decrease in the durability of the sterilization tank 1 caused by an increase in thermal stress due to a sudden temperature change.

In addition, in this embodiment, as described above, the heat sterilization method includes a step S1 of preheating the sterilization tank 1 using the medium-temperature water Htm heated during heat recovery of the sterilization tank 1 before supplying the high-temperature water Hth for performing the object heating process (heat sterilization control) of the retort pouch Rp (sterilization object) to the sterilization tank 1. By preheating the sterilization tank 1, the initial temperature of the sterilization tank 1 at the start of the object heating process (heat sterilization control) can be increased, so that the amount of heat given to the high-temperature water Hth during the temperature increase to raise the high-temperature water Hth to the temperature for performing the object heating process (heat sterilization control) can be reduced compared to the case where preheating is not performed. In addition, by using the medium-temperature water Htm after the medium-temperature water heat recovery process (medium-temperature water heat recovery control) to preheat the sterilization tank 1, the heat of the sterilization tank 1 and the retort pouch Rp (sterilization object) after the object heating process (heat sterilization control) can be used to raise the temperature of the medium-temperature water Htm to the preheating temperature. As a result, when preheating the sterilization tank 1 with the medium-temperature water Htm after the medium-temperature water heat recovery process (medium-temperature water heat recovery control), the thermal energy required in the heat sterilization device 100 due to the preheating can be reduced, and the amount of (high-temperature) steam used to raise the temperature of the high-temperature water Hth can be reduced accordingly.

In addition, in this embodiment, as described above, in the preheating process, the control unit 12 closes the flow path switching valves 6d, 6e, and 7b, and opens the flow path switching valves 5g and 8b, thereby forming the medium-temperature water injection path Sp1, and then controls the medium-temperature water Htm in the medium-temperature water tank 4 to be injected into the sterilization tank 1 via the medium-temperature water injection path Sp1 using the circulation pump 5f. This makes it possible to inject the medium-temperature water Htm from the medium-temperature water tank 4 into the sterilization tank 1 without using a pump other than the circulation pump 5f.

In addition, in this embodiment, as described above, in the preheating process, the control unit 12 closes the flow path switching valves 5g, 6d, 7b, and 8b, and opens the flow path switching valve 6e, thereby forming the medium temperature water recovery passage Re1, and then performs recovery control to recover the medium temperature water Htm into the medium temperature water tank 4 via the medium temperature water recovery passage Re1 using the circulation pump 5f. This makes it possible to recover the medium temperature water Htm from the sterilization tank 1 to the medium temperature water tank 4 without using a pump other than the circulation pump 5f.

In addition, in this embodiment, as described above, in the medium-temperature water heat recovery process, the control unit 12 closes the flow path switching valves 6d, 7b, and 6e, and opens the flow path switching valves 5g and 8b to form the medium-temperature water injection path Sp3, and then controls the medium-temperature water Htm in the medium-temperature water tank 4 to be injected into the sterilization tank 1 via the medium-temperature water injection path Sp3 using the circulation pump 5f. This makes it possible to inject the medium-temperature water Htm from the medium-temperature water tank 4 into the sterilization tank 1 without using a pump other than the circulation pump 5f.

In addition, in this embodiment, as described above, in the medium-temperature water heat recovery process, the control unit 12 closes the flow path switching valves 5g, 6d, 7b, and 8b, and opens the flow path switching valve 6e, thereby forming the medium-temperature water recovery passage Re3, and then performs recovery control to recover the medium-temperature water Htm into the medium-temperature water tank 4 via the medium-temperature water recovery passage Re3 using the circulation pump 5f. This makes it possible to recover the medium-temperature water Htm from the sterilization tank 1 to the medium-temperature water tank 4 without using a pump other than the circulation pump 5f.

In the present embodiment, the supply path 6 is a pipe branching off from the circulation path 5 to supply high-temperature water Hth to the high-temperature water tank 3. The supply path 6 is a pipe branching off from the circulation path 5 to supply medium-temperature water Htm to the medium-temperature water tank 4. The supply path 6 includes a common pipe 6a. The common pipe 6a is connected to the circulation path 5 and is a common pipe for the high-temperature water tank 3 and the medium-temperature water tank 4. As a result, when the sterilization tank 1 is preheated with the medium-temperature water Htm, the medium-temperature water Htm flows through the common pipe 6a, so that not only the sterilization tank 1 but also the common pipe 6a is preheated by the medium-temperature water Htm. Therefore, compared to a case where the piping connecting the sterilization tank 1 to the high-temperature water tank 3 and the medium-temperature water tank 4 is not shared, the common pipe 6a is also preheated when the high-temperature water Hth is supplied to the sterilization tank 1 after the sterilization tank 1 is preheated, so that a sudden temperature rise can be suppressed not only in the sterilization tank 1 but also in the common pipe 6a. As a result, the risk of cracks occurring due to stress caused by a sudden temperature rise can be reduced not only in the sterilization tank 1 but also in the common pipe 6a. In addition, when recovering heat from the sterilization tank 1 using the medium temperature water Htm, the medium temperature water Htm flows through the common pipe 6a heated by the high temperature water Hth when recovering the high temperature water Hth in the sterilization tank 1 to the high temperature water tank 3, so that not only the heat from the sterilization tank 1 but also the heat from the common pipe 6a heated by the high temperature water Hth is recovered by the medium temperature water Htm. This allows the heat of the common pipe 6a heated by the high temperature water Hth to be recovered, so the temperature of the medium temperature water Htm used to preheat the sterilization tank 1 the next time can be made higher than when the common pipe 6a is not used.

In addition, in this embodiment, as described above, the medium-temperature water tank 4 is a tank that collects and stores the medium-temperature water Htm stored in the sterilization tank 1 after preheating and after heat recovery. This makes it possible to store the medium-temperature water Htm for preheating by recovering the medium-temperature water Htm after heat recovery, and to store the medium-temperature water Htm for heat recovery by recovering the medium-temperature water Htm after preheating. This allows the supply source of the medium-temperature water Htm to the sterilization tank 1 and the destination of the medium-temperature water Htm recovered from the sterilization tank 1 to be the single medium-temperature water tank 4, making it possible to realize a heating sterilization device 100 that performs heat recovery and preheating with a simple configuration.

[Modification]
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the above embodiment, the heat sterilization device 100 is a spray type device equipped with a spray nozzle 2, but the present invention is not limited to this. In the present invention, the heat sterilization device may be a hot water storage type device that performs preheating and heat recovery using medium temperature water, or a steam type device that uses steam as the high-temperature fluid.

For example, in the first modified example of the hot water storage type heat sterilization device 500 shown in FIG. 23, the heat sterilization control is performed as follows. That is, after the control unit 512 heats and sterilizes the retort pouch Rp (sterilization object) with high-temperature water Hth (high-temperature fluid) in the object heating process, the control unit 512 recovers the high-temperature water Hth (high-temperature fluid) discharged from the sterilization tank 1 into the high-temperature water tank 503, and then performs medium-temperature water heat recovery control to recover the heat of the sterilization tank 1 after heat sterilization using medium-temperature water Htm generated separately from the high-temperature water Hth (high-temperature fluid).

Here, in the hot water storage type heat sterilization device 500, high temperature water Hth (high temperature fluid) is not used for heat sterilization, but after recovering the high temperature water Hth in the high temperature water tank 503, the medium temperature water Htm in the medium temperature water tank 4 is circulated to the sterilization tank 1, thereby recovering heat from the sterilization tank 1 after heat sterilization, and therefore it is possible to prevent the temperature of the high temperature water Hth from decreasing.

Furthermore, for example, in the steam-type heat sterilization device 600 of the second modified example shown in FIG. 24, the heat sterilization control is performed as follows. That is, the control unit 612 heats and sterilizes the retort pouch Rp (sterilization object) with high-temperature steam Vah (high-temperature fluid) in the object heating process, and then performs medium-temperature water heat recovery control to recover heat from the sterilization tank 1 after heat sterilization using medium-temperature water Htm generated separately from the high-temperature steam Vah (high-temperature fluid).

Here, the steam-type heat sterilization device 600 uses steam Vah (high-temperature fluid) for heat sterilization instead of high-temperature water, so heat recovery using high-temperature water cannot be performed. However, with the above-mentioned configuration of the second modified example of this embodiment, by performing medium-temperature water heat recovery control, the steam-type heat sterilization device 600 can also recover heat from the sterilization tank 1 after heat sterilization.

In the above embodiment, the heat sterilization device 100 is provided with both the high temperature water tank 3 and the medium temperature water tank 4, but the present invention is not limited to this. In the present invention, the heat sterilization device only needs to be provided with a medium temperature water tank, and does not necessarily need to be provided with a hot water tank.

In the above embodiment, the heat sterilization device 100 is an example of a device that heats and sterilizes a retort pouch Rp containing food using high-temperature water Hth, but the present invention is not limited to this. In the present invention, the heat sterilization device may also be a device that heats and sterilizes other products, such as canned goods.

In the above embodiment, the control unit 12 is configured to directly use the medium-temperature water Htm supplied from the medium-temperature water tank 4 to preheat the sterilization tank 1 and the retort pouch Rp and to recover heat, but the present invention is not limited to this. In other words, the heat sterilization device may have a modified configuration that indirectly uses medium-temperature water, as follows.

Specifically, as in the third modified example shown in FIG. 25, the heat sterilization device 700 includes a heat transfer fluid supply unit 713 that supplies a heat transfer fluid Htf heated by medium-temperature water Htm. The heat sterilization device 700 includes a heat exchanger 714 that exchanges heat between the medium-temperature water Htm stored in the medium-temperature water tank 704 and the heat transfer fluid Htf supplied from the heat transfer fluid supply unit 713. The control unit 12 controls the supply of the heat transfer fluid Htf, whose temperature has been increased by heat exchange with the medium-temperature water Htm in the heat exchanger 714, to the sterilization tank 1 during preheating of the sterilization tank 1, and controls the supply of the heat transfer fluid Htf, whose temperature has been decreased by heat exchange with the medium-temperature water Htm in the heat exchanger 714, to the sterilization tank 1 during heat recovery of the sterilization tank 1.

As a result, in preheating the sterilization tank 1, the heat transfer fluid Htf and the medium-temperature water Htm are heated by heat exchange in the heat exchanger 714, and the heat transfer fluid Htf can be supplied to the sterilization tank 1 while gradually increasing the temperature of the heat transfer fluid Htf. Therefore, the temperature of the sterilization tank 1 can be gradually increased to the preheating temperature by the heat transfer fluid Htf while suppressing the temperature difference with the sterilization tank 1. As a result, a sudden change in temperature of the sterilization tank 1 can be further suppressed. In addition, by recovering heat by heat exchange between the heat transfer fluid Htf and the medium-temperature water Htm in the heat exchanger 714, the temperature of the heat transfer fluid Htf can be gradually decreased while the heat transfer fluid Htf is supplied to the sterilization tank 1. Therefore, the temperature difference with the sterilization tank 1 can be suppressed, and the sterilization tank 1 can be gradually lowered to the post-heat recovery temperature (pre-cooling temperature) by the heat transfer fluid Htf. As a result, a sudden change in temperature of the sterilization tank 1 can be further suppressed.

In the third modified example shown in FIG. 25, the medium-temperature water tank 704 is connected to the heat exchanger 714. That is, the medium-temperature water tank 704 includes an inlet pipe 704c, a supply pipe 704d, a flow path switching valve 704e, and a flow path switching valve 704f.

In the above embodiment, the control unit 12 performs both the control of recovering and storing the medium-temperature water Htm in the sterilization tank 1 after preheating in the medium-temperature water tank 4, and the control of recovering and storing the medium-temperature water Htm in the sterilization tank 1 after heat recovery in the medium-temperature water tank 4, but the present invention is not limited to this. In the present invention, it is sufficient that the control unit performs at least one of the control of recovering and storing the medium-temperature water in the sterilization tank after preheating in the medium-temperature water tank, and the control of recovering and storing the medium-temperature water in the sterilization tank after heat recovery in the medium-temperature water tank.

In the above embodiment, for the sake of convenience, an example has been shown in which the control processing of the control unit 12 is explained using a flow-driven flowchart in which processing is performed in order according to a processing flow, but the present invention is not limited to this. In the present invention, the control processing of the control unit may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the control processing may be performed completely event-driven, or may be a combination of event-driven and flow-driven.

1 Sterilization tank 1d Storage space 3, 503 High temperature water tank 4, 704 Medium temperature water tank 5 Circulation path (first connection path, second connection path)
5a Discharge pipeline (first connection path, second connection path)
5b Discharge pipeline (first connection path, second connection path)
5c Upstream pipeline (first connection path, second connection path)
5d downstream pipe 5d (first connection path, second connection path)
5f Circulation pump 6a Common pipe (first connection path, second connection path)
6b Branch pipe (second connection path)
6c Branch pipe (first connection path)
11 Heat exchanger 12, 612 Control unit 100, 500, 600, 700 Heat sterilization device 713 Heat transfer fluid supply unit 714 Heat exchanger Cw Cooling water Htf Heat transfer fluid Hth High temperature water Htm Medium temperature water Rp Retort pouch (object to be sterilized)

Claims (12)

A sterilization tank having an accommodation space for accommodating an object to be sterilized by heat sterilization using a high-temperature fluid, and supplied with the high-temperature fluid for heat sterilizing the object and cooling water for cooling the object that has been heat sterilized by the high-temperature fluid;
and a control unit that performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization, using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water and lower than that of the high-temperature fluid, before the object to be sterilized is cooled by the cooling water. The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control when the high-temperature fluid after heat sterilization is discharged from the sterilization tank. Further comprising a medium-temperature water tank in which the medium-temperature water is stored,
The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization, using the medium-temperature water supplied from the medium-temperature water tank, before cooling of the object to be sterilized by the cooling water, and to store the medium-temperature water used for the medium-temperature water heat recovery control in the medium-temperature water tank. The heat sterilization device according to claim 3, wherein the control unit is configured to perform preheating control to preheat the sterilization tank using the medium-temperature water that has been heated during the medium-temperature water heat recovery control and stored in the medium-temperature water tank before the object to be sterilized is heated by the high-temperature fluid. A first connection path is further provided to connect the sterilization tank and the medium temperature water tank to each other.
The heat sterilization device according to claim 4, wherein the control unit is configured to perform control to recover and store the medium-temperature water in the sterilization tank after heat recovery in the medium-temperature water tank via the first connection path, and to control to supply the medium-temperature water to the sterilization tank via the first connection path during preheating. The heat sterilization device according to claim 4, wherein the control unit is configured to control the release of the medium-temperature water supplied from the medium-temperature water tank toward the object to be sterilized during each of the preheating of the sterilization tank and the heat recovery of the sterilization tank. a high-temperature water tank for collecting and storing the high-temperature water, which is the high-temperature fluid after heat sterilization stored in the sterilization tank;
A second connection path connecting the sterilization tank and the high-temperature water tank to each other is further provided.
The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control of the sterilization tank after the high-temperature water discharged from the sterilization tank upon completion of heat sterilization of the object to be sterilized is recovered into the high-temperature water tank via the second connection path. a heat transfer fluid supply unit that supplies a heat transfer fluid heated by the medium-temperature water;
The heat transfer fluid supply unit supplies heat to the heat transfer system, and the heat transfer fluid is supplied to the heat transfer system through a heat exchanger.
The heating and sterilizing apparatus according to claim 3, wherein the control unit is configured to control the supply of the heat transfer fluid, the temperature of which has been increased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank during preheating of the sterilization tank, and to control the supply of the heat transfer fluid, the temperature of which has been decreased by heat exchange with the medium-temperature water in the heat exchanger, to the sterilization tank during heat recovery of the sterilization tank. The cooling water, the high-temperature fluid, and the medium-temperature water discharged from the sterilization tank are discharged through a circulation path including a circulation pump for circulating the cooling water, the high-temperature fluid, and the medium-temperature water to the sterilization tank,
The heat sterilization device according to claim 1, wherein the control unit is configured to perform the medium-temperature water heat recovery control by circulating the medium-temperature water to the sterilization tank through the circulation path using the circulation pump. An object to be sterilized that has been heat sterilized by a heat sterilization device that has a storage space for storing the object to be heat sterilized with a high-temperature fluid, a sterilization tank to which the high-temperature fluid for heat sterilizing the object and cooling water for cooling the object to be sterilized with the high-temperature fluid are supplied, and a control unit that performs medium-temperature water heat recovery control to recover heat from the sterilization tank after heat sterilization using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water but lower than that of the high-temperature fluid before the object to be sterilized is cooled by the cooling water. A step of supplying a high-temperature fluid to a sterilization tank in which heat sterilization is performed using the high-temperature fluid, and heat sterilizing an object to be sterilized in the sterilization tank;
Before cooling the object to be sterilized by the cooling water, heat recovery is performed in the sterilization tank after the thermal sterilization using medium-temperature water that is generated separately from the high-temperature fluid and has a temperature higher than that of the cooling water and lower than that of the high-temperature fluid;
The heat sterilization method includes a step of cooling the heat-sterilized object to be sterilized with the cooling water after heat recovery of the sterilization tank. The heat sterilization method according to claim 11, further comprising a step of preheating the sterilization tank using the medium-temperature water heated during the heat recovery from the sterilization tank before supplying the high-temperature fluid for heat sterilizing the object to the sterilization tank.