JP5178771B2 - Freezer refrigerator - Google Patents

Description

  The present invention relates to a refrigerator-freezer.

  The refrigeration cycle of the refrigerator / freezer is composed of a compressor, a condenser, a capillary tube, and an evaporator in this order, and cools the air in the cabinet with the evaporator. The air cooled by the evaporator is sent out to a room (a refrigerator room, a freezer room, a vegetable room, etc.) in the warehouse by a fan in the warehouse, and forms a circulation air path that returns from each room to the evaporator again. Moisture contained in the room air due to door opening and closing and foods adheres to the surface of the low-temperature evaporator and forms frost. When the cooling operation is performed for about one day, the evaporator is covered with frost, the ventilation resistance of the evaporator is increased and the air volume is decreased, and the thermal resistance between the refrigerant and the air is increased and the refrigeration capacity is decreased. Therefore, it is necessary to defrost the evaporator once a day in order to prevent a decrease in capacity.

In Patent Document 1, as a defrosting means, a hot gas system in which a bypass pipe connecting between a compressor and a condenser and between a capillary tube and an evaporator is connected and the refrigerant flow path is switched to the bypass pipe during a defrosting operation. Is disclosed. Further, an operation method is disclosed in which the compressor is stopped when the temperature of the evaporator reaches a predetermined temperature during the defrosting operation. In addition, an operation method is disclosed in which a heater is disposed in a tray section disposed at the lower part of the evaporator, and the heater is heated when the temperature of the tray section reaches around 0 ° C.
Japanese Patent Application Laid-Open No. H10-228707 discloses a refrigeration cycle provided with a hot gas bypass circuit and flowing hot gas to an evaporator via a drain pan.
In Patent Document 3, a hot gas bypass circuit is provided in the refrigeration cycle, the bypass pipe is branched into two branches, and a bypass directly passing to the evaporator and a bypass via a drain pan heating pipe are shown.

JP-A-2005-249254 (pages 4 to 6, FIG. 1) JP-A-61-159072 (pages 3 to 4, FIGS. 1 and 2) Japanese Utility Model Publication No. 62-093659 (pages 3 to 4, page 8, FIG. 2)

  The current refrigerator is generally a heater type defrost, but in the form in which the evaporator is arranged in the vicinity of the freezer compartment, the ratio of the heat of the heater leaking into the cabinet is high, and the power consumption is increased. In the hot gas type, the cooler can be directly heated. However, there are problems that frost falls and remains in the tray, and that heat is radiated from the compressor shell and much heat is available for defrosting. Moreover, in order to suppress the fall of cooling capacity and reduce power consumption, it is desired to reduce the amount of frost formation to an evaporator.

  In the refrigerator-freezer disclosed in Patent Document 1, as described above, the hot gas method is used for defrosting the evaporator, and the heater method is used for defrosting the tray to save power during defrosting. However, there is a problem that the power saving effect is insufficient in that the heater is used. In addition, there is a problem that the configuration is complicated in that the hot gas method and the heater method are used together. In addition, immediately after the defrosting is completed, the normal operation (cooling operation) is immediately started, so the heat of the evaporator heated during the defrosting is dissipated into the chamber, so that the temperature inside the chamber rises and cools down. There was a problem that wasteful power was consumed. Moreover, there existed a problem of reducing the food quality in a store | warehouse | chamber by the rise in chamber | room temperature.

  Although what was disclosed by patent document 2 and patent document 3 uses the hot gas system for the defrosting of an evaporator, there existed a problem that it was not considered about the operation | movement used as power saving. Further, since all of the defrosting is processed by the evaporator, there is a problem that the cooling air passage is easily clogged by the frost that has fallen from the evaporator onto the tray and the cooling capacity tends to be reduced.

  Further, in the prior art document 1 and the prior art document 3, the hot gas system has a configuration in which a switching valve is installed at a branch portion between the discharge side of the compressor and the condenser. For this reason, a high pressure is applied to the switching valve, and if the valve diameter is small, there is a problem that pressure loss occurs and performance deteriorates. In addition, in order to reduce the influence of pressure loss, it is necessary to increase the valve diameter, and there is a problem that the equipment is increased in size. On the other hand, when a switching valve is installed at the branch portion that is at a low pressure between the expansion valve and the cooler inlet, the refrigerant is liquefied and stored in the circuit on the condenser side during defrosting operation (hereinafter also referred to as “sleeping”). ), The refrigerant required for defrosting is insufficient, and there is a problem that the defrosting time becomes long.

  This invention is made in order to solve the above subjects, and obtains the refrigerator-freezer which can reduce the amount of frost formation to an evaporator. Moreover, the refrigerator-freezer which can reduce the power consumption at the time of a defrost operation is obtained. Moreover, the refrigerator refrigerator which can suppress the raise of the internal temperature by a defrost driving | operation and can suppress the fall of preservation | save quality, such as a foodstuff in a warehouse, is obtained. Moreover, the refrigerator is miniaturized and the refrigerator refrigerator which can exhibit sufficient defrosting capability is obtained.

The refrigerator-freezer according to the present invention includes a main circuit in which a compressor, a condenser, a decompression unit, a tray pipe, and an evaporator are sequentially connected by a pipe to circulate a refrigerant, the compressor of the main circuit, and the condenser A bypass circuit that branches from a pipe that connects the pressure reducing means of the main circuit and a pipe that connects the tray pipe, a switching means that switches a refrigerant flow path to the main circuit or the bypass circuit, and the evaporator And a cooling chamber in which an air passage that circulates the air in the cabinet is formed, and a tray that is provided below the evaporator and receives water and frost falling from the evaporator, The tray pipe is installed upstream of the evaporator in the air path and in the vicinity of the tray.

  In the present invention, the tray piping is located upstream of the evaporator in the air passage of the cooling chamber and in the vicinity of the tray, so that the amount of frost formation on the evaporator can be reduced.

It is a circuit diagram of the refrigerating cycle in Embodiment 1 of this invention. It is a rear view of the refrigerator-freezer in Embodiment 1 of this invention. It is a front view of the cooling chamber 17 of the refrigerator-freezer in Embodiment 1 of this invention. It is the front view and side view which show the tray 19 of the refrigerator-freezer in Embodiment 1 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 1 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 1 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 1 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 1 of this invention. It is side surface sectional drawing of the cooling chamber 17 in Embodiment 1 of this invention. It is a path | pass structure of the evaporator 5 of the refrigerator-freezer in Embodiment 1 of this invention. It is a block which shows the structure of the control system in Embodiment 1 of this invention. It is a control flowchart of the refrigerator-freezer in Embodiment 1 of this invention. It is a control time chart corresponding to the control flow of FIG. It is another control flowchart of the refrigerator-freezer in Embodiment 1 of this invention. It is a control time chart corresponding to the control flow of FIG. It is a rear view of the refrigerator-freezer in Embodiment 2 of this invention. It is a front view of the cooling chamber 17 of the refrigerator-freezer in Embodiment 2 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 2 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 2 of this invention. It is a top view of tray piping 8 of the refrigerator-freezer in Embodiment 2 of this invention. It is a circuit diagram of the refrigerating cycle in Embodiment 3 of this invention. It is a rear view of the refrigerator-freezer in Embodiment 3 of this invention. It is a front view of the cooling chamber 17 of the refrigerator-freezer in Embodiment 3 of this invention. It is a rear view of another freezer refrigerator in Embodiment 3 of this invention. It is a front view of the cooling chamber 17 of the refrigerator-freezer of FIG. It is a block diagram which shows the structure of the control system in Embodiment 3 of this invention. It is a control flowchart of the refrigerator-freezer in Embodiment 3 of this invention. It is a front view of the cooling chamber 17 of the refrigerator-freezer in Embodiment 4 of this invention. It is a front view of the cooling chamber 17 of the refrigerator-freezer in Embodiment 5 of this invention.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of a refrigeration cycle according to Embodiment 1 of the present invention.
In FIG. 1, the refrigeration cycle circuit of the refrigerator-freezer in the present embodiment includes a compressor 1, a condenser 3, a capillary tube (capillary tube) 4, a tray pipe 8, and an evaporator 5 that are sequentially connected by a pipe to circulate the refrigerant. A bypass circuit 9 that branches from a main circuit 6 to be connected, a pipe that connects the compressor 1 and the condenser 3 to a pipe that connects the capillary 4 and the tray pipe 8, and a refrigerant flow to the main circuit 6 or the bypass circuit 9 A three-way valve 2 for switching the path and a tray 19 provided below the evaporator 5 and receiving water and frost falling from the evaporator 5 are provided. A dryer 14 may be provided between the condenser 3 and the capillary 4. The diaphragm circuit 7 may be provided in the bypass circuit 9.

  Also, an evaporator fan 23 that blows air cooled by the evaporator 5 into the cabinet, an evaporator temperature sensor 32 that detects the temperature of the evaporator 5, a tray temperature sensor 33 that detects the temperature of the tray 19, The compressor 1, the three-way valve 2, and the control part 31 which controls operation | movement of the evaporator fan 23 are provided.

  The capillary 4 exchanges heat with the suction pipe 22 that connects the evaporator 5 and the suction side of the compressor 1. The evaporator 5 is housed in a cooling chamber 17 which will be described later, and is disposed in an air path that circulates the air in the warehouse. The evaporator 5 is composed of, for example, a fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins. The tray pipe 8 is installed in the vicinity of the tray 19 upstream of the evaporator 5 in the air passage. Details will be described later. The tray 19 includes a drain port 20 that discharges water dropped from the evaporator 5 and water generated by melting of frost to the outside of the cabinet, and a drain hose 21 that extends downward from the drain port 20. Further, a drain pan 13 for receiving drain discharged through the drain hose 21 is provided.

  The three-way valve 2 is provided in a pipe connecting the capillary 4 and the tray pipe 8. That is, one of the three sides is connected to the capillary 4, one of the three sides is connected to the tray pipe 8, and one of the three sides is connected to the bypass circuit 9.

The “capillary tube 4” corresponds to the “decompression unit” in the present invention.
The “three-way valve 2” corresponds to “switching means” in the present invention.
Here, the case where a capillary tube (capillary tube) is used as the decompression means will be described. However, the present invention is not limited to this, and an electric expansion valve capable of arbitrarily adjusting the amount of throttling, a variable expansion valve or the like is used. Also good.
In addition, although the case where what switches a three-way flow path, such as a three-way valve, is used as a switching means is described here, the present invention is not limited to this, and a switch that opens and closes a two-way flow path such as an on-off valve. What is necessary is just to be able to switch a flow path, such as combining two.

FIG. 2 is a rear view of the refrigerator-freezer according to Embodiment 1 of the present invention.
As shown in FIG. 2, a machine room 10 is provided on the lower side of the back surface of the refrigerator-freezer main body. In the machine room 10, there are a compressor 1, a machine room fan 11 for forcibly air cooling the shell of the compressor 1, a forced air cooling condenser 3 a such as a heat exchanger constituting the condenser 3, a drain pan 13, and a dryer 14. Is included. The piping of the main circuit 6 is connected to the forced air-cooled condenser 3a from the compressor 1, and after exiting the forced air-cooled condenser 3a, the inside of the steel plate 15 of the refrigerator which is a natural heat dissipation condenser constituting the condenser 3 Connect to the pipe installed in. The main circuit 6 passes from the natural heat radiation condenser through the capillary 14 disposed inside the heat insulating wall 16 through the dryer 14 and enters the refrigerator through the hole 18 at the cooling chamber inlet.

  On the other hand, the bypass circuit 9 branches from between the compressor 1 and the condenser 3, passes through the inside of the heat insulating wall 16 on the back of the refrigerator, and enters the refrigerator through the hole 18 at the inlet of the cooling chamber. The three-way valve 2 is installed in the heat insulating wall 16 or in the cooling chamber 17. The bypass circuit 9 divides the piping from between the compressor 1 and the condenser 3 to the hole 18 at the cooling chamber inlet, inside the heat insulating wall 16 on the back of the refrigerator, in the thickness direction, from the center to the outer half. If it passes through the range, heat insulation is good, wasteful heat dissipation can be prevented, and the heat of hot gas can be efficiently used for defrosting. However, when the pipe touches the steel plate 15 on the back surface, heat is easily released to the outside due to the fin effect, so that the steel plate 15 is not touched.

FIG. 3 is a front view of cooling chamber 17 of the refrigerator-freezer according to Embodiment 1 of the present invention.
4 is a front view and a side view showing a tray 19 of a refrigerator-freezer according to Embodiment 1 of the present invention.
As shown in FIG. 3, the evaporator 5 is disposed in the center of the cooling chamber 17. In addition, an evaporator fan 23 that blows the air cooled by the evaporator 5 into the cabinet is disposed above the evaporator 5. A tray 19 is disposed below the evaporator 5. The main circuit 6 entering from the hole 18 at the cooling chamber inlet of the cooling chamber 17 passes through the tray pipe 8 arranged on the tray 19 from the three-way valve 2 and is connected to the evaporator 5. Further, the bypass circuit 9 entered from the hole 18 at the cooling chamber inlet is connected to the three-way valve 2. As shown in FIG. 4, the tray 19 is provided with a drainage port 20 at substantially the center thereof, and the bottom surface of the tray 19 is inclined so as to gradually become lower from the edge toward the drainage port 20.

5 to 8 are top views of the tray piping 8 of the refrigerator-freezer according to Embodiment 1 of the present invention.
For example, the tray 19 has a width of about 400 mm and a depth of about 70 mm, and the drain 19 is open at the center of the tray 19. The tray pipe 8 is disposed so as to pass near the drain port 20 or above the drain port 20. For example, the tray pipe 8 is arranged around the drain outlet 20 as shown in FIG. Further, for example, as shown in FIG. 6, the tray pipe 8 is bent six times in a meandering manner and arranged so as to pass along the drain port 20 or to pass over the drain port 20. For example, as shown in FIG. 7, the tray pipe 8 may be wound around the circumference of the drain port 20.

  When the shape of the tray pipe 8 is meandered, the heat transfer area with the frost increases and the defrosting time can be shortened. A drain hose 21 is connected to the tip of the drain port 20, and the drain flows from the tray 19 through the drain hose 21 to the drain pan 13 of the machine room 10. The drain port 20 may be frozen and blocked during the cooling operation, and if the drain port 20 is blocked at the start of defrosting, the drain overflows from the tray 19 and leaks into the cabinet. By passing the tray pipe 8 over the circumference of the drain port 20 or the drain port 20, the drain port 20 is warmed simultaneously with the defrosting operation and the ice in the drain port 20 is melted, so that the drain can be prevented from overflowing. By forming the tray pipe 8 on the circumference of the drain port 20, the drain port 20 is further easily heated.

  When the tray pipe 8 is placed along the entire tray 19, the defrosting time is faster, but the size of the tray 19 is about 400mm wide and about 70mm deep, and the tray pipe 8 is made of copper with a diameter of 4mm and a wall thickness of 0.3mm. The minimum radius of bending is about 15 mm, and even if meandering, it will be 6 or 7 reciprocations at most. The inlet and outlet pipes of the evaporator 5 are unified on the side closer to the hole 18 at the inlet of the cooling chamber so that the handling is easy. The tray pipe 8 is also connected to the same side as the cooling chamber inlet hole 18 and the evaporator 5 inlet so that the pipe can be connected without waste.

  In FIG. 8, the tray pipe 8 is arranged in the width direction of the tray 19, and the number of bendings is reduced and the productivity is better than the meandering. In order to unify the entrance / exit of the tray piping 8 on the same side, the piping shape is as shown in FIG.

Next, the operation will be described.
[Cooling operation]
In a normal cooling operation, the capillary 4 and the tray pipe 8 are connected and the three-way valve 2 is switched so as to close the bypass circuit 9. The gas refrigerant compressed to high temperature and high pressure by the compressor 1 dissipates heat to the outside by the condenser 3 and is condensed into liquid refrigerant, becomes low temperature and low pressure by the capillary 4, and sucks heat from the air by the tray pipe 8 and the evaporator 5. The refrigerant evaporates. Air cooled by passing through the tray pipe 8 and the evaporator 5 circulates in the cabinet to cool the room. Moisture in the outside air that flows into the cabinet when the door is opened and closed and frost from the food form frost in the evaporator 5, so if the cooling operation is performed for about one day, the evaporator 5 is covered with frost and the ventilation resistance increases. As the air volume decreases, the thermal resistance between the refrigerant and the air increases and the refrigeration capacity decreases. Therefore, it is necessary to defrost the evaporator 5 about once a day in order to prevent a decrease in capacity.

Here, FIG. 9 shows a cross-sectional view of the cooling chamber 17 as seen from the side. Air flowing in from the refrigerator is represented by a thick arrow.
As shown in FIG. 9, the cooling chamber 17 is formed with an air passage for circulating the air in the cabinet. This air passage is formed so as to reach the evaporator 5 through the upper surface of the tray from the suction port communicating with the interior, and communicate with the interior again. During normal operation (cooling operation), the air in the cabinet is sucked from the suction port by the evaporator fan 23 disposed above the evaporator 5, and the air flowing into the lower portion of the evaporator 5 through this suction port is , Flows along the tray 19 and then flows into the evaporator 5 from the back side. As described above, since the low-temperature and low-pressure refrigerant is circulating in the tray pipe 8 during the cooling operation, it cools by absorbing heat from the internal air. At this time, moisture contained in the air is frosted on the tray pipe 8 by being cooled by the tray pipe 8.

  As described above, in the first embodiment, the tray pipe 8 is arranged on the tray 19. That is, a part of the frost of the evaporator 5 can be frosted on the tray pipe 8 by disposing the tray pipe 8 upstream of the evaporator 5 in the air passage through which the internal air flows. Thereby, the amount of frost formation in the evaporator 5 can be reduced. Moreover, since the wind speed of air is quick on the tray 19, the amount of frost formation can also be taken. In addition, since the space through which air flows is vacant in the tray pipe 8 as compared with the evaporator 5, clogging is less likely, cooling capacity reduction in the evaporator 5 can be suppressed, and the cooling operation time can be extended.

[Defrosting operation]
In the defrosting operation, the bypass circuit 9 and the tray pipe 8 are connected, and the three-way valve 2 is switched so as to close the main circuit 6. The high-temperature gas refrigerant discharged from the compressor 1 flows from the bypass circuit 9 through the tray pipe 8 to the evaporator 5, the tray pipe 8 and the evaporator 5 are heated, and the tray pipe 8 and the evaporator 5 are frosted. Melt the frost. At this time, the frost in the tray pipe 8 is gradually melted because it has accumulated on the pipe, but the frost in the evaporator 5 melts from the pipe and the fin surface, so that the frost slides down from the upper part of the evaporator 5 to the lower part. The frost falls to the tray 19 below the evaporator 5. The frost dropped from the evaporator 5 can be melted by the tray pipe 8. As a result, when the cooling operation is resumed while the frost remains on the tray 19, the frost grows greatly, and finally the air path is blocked and the cold air cannot reach the room and can be prevented from being cooled. In addition, since the frost of the evaporator 5 slides down from the upper part of the evaporator to the lower part, the frost tends to remain in the lower part of the evaporator 5. For this reason, as shown in FIG. 10, it is more preferable to use a path configuration in which a high-temperature refrigerant flows from the lower part of the evaporator 5 upward, because the frost on the lower part of the evaporator 5 is easily melted.

  In the defrosting operation, since the main circuit 6 is closed, the pressure of the condenser 3 is high. A part of the condenser 3 is a pipe (natural heat radiation condenser) installed inside the steel plate 15 of the refrigerator, and is cooled by low-temperature air in the refrigerator that is cooled during normal operation. For this reason, the refrigerant condenses in the piping (natural heat radiation condenser) constituting the condenser 3. When the state where the main circuit 6 is closed continues, the refrigerant is gradually liquefied and stored in the condenser 3 (sleeps), and the refrigerant necessary for the defrosting operation becomes insufficient. Therefore, the three-way valve 2 is intermittently switched between the main circuit 6 and the bypass circuit 9 so that the refrigerant that has fallen into the condenser 3 can be discharged, and sufficient defrosting capability can be obtained to melt the frost. Driving is possible.

  In addition, since the defrosting cannot be performed when the three-way valve 2 is switched to the main circuit 6 and the capillary 4 and the tray pipe 8 are connected, intermittent switching of the three-way valve 2 is bypassed from the switching time on the main circuit 6 side. The switching time on the circuit 9 side is lengthened.

[Control action]
Next, the control operation will be described with reference to FIG. 1, FIG. 11, FIG. 12, and FIG.
FIG. 11 is a block diagram showing the configuration of the control system in the first embodiment of the present invention.
As shown in FIG. 11, the control system includes a control unit 31, an evaporator temperature sensor 32 connected to the control unit 31, a tray temperature sensor 33, an evaporator fan 23 and a fan motor 231, the compressor 1 and The compressor motor 101, the three-way valve 2 and the three-way valve driving means 201, the throttle mechanism 7 and the throttle mechanism driving means 701 are provided.

FIG. 12 is a control flowchart of the refrigerator-freezer according to Embodiment 1 of the present invention.
FIG. 13 is a control time chart corresponding to the control flow of FIG.
Hereinafter, based on each step of FIG. 12, it demonstrates with reference to FIG.
The defrosting operation based on the control flow of FIG. 12 includes a tray / evaporator defrosting step (STEP 1) and an evaporator cooling step (STEP 2). Further, after the defrosting operation is completed, the operation is shifted to the normal operation (STEP 3).

[Tray / evaporator defrosting process]
When the defrosting operation is started, the control unit 31 controls the fan motor 231 to stop the operation of the evaporator fan 23 (step S11). The controller 31 controls the three-way valve driving means 201 to switch the three-way valve 2 so that the discharge gas of the compressor 1 flows to the bypass circuit 9 (step S12). The control unit 31 controls the compressor motor 101 to change the frequency of the compressor 1 to the frequency α during defrosting (step S13). In general, during normal operation, the compressor 1 is operated at a lower frequency, so the frequency α during defrosting is greater than the frequency during normal operation. The defrosting time can be shortened by setting the value as large as possible in consideration of the current value limitation and the liquid back reliability to the compressor 1.
The “frequency α” corresponds to the “first rotational speed” in the present invention.

  When the three-way valve 2 is switched to the bypass circuit 9, the high and low pressures approach a pressure equalization state, and the refrigerant suddenly flows into the bypass circuit 9 to generate refrigerant sound. Therefore, in order to solve this problem, it is preferable to reduce the frequency of the compressor 1 or stop the compressor 1 before switching the three-way valve 2 to the bypass circuit 9 in step S12. At this time, if the compressor 1 is stopped, it is necessary to ensure the time until restart for reliability, and it takes time for defrosting. Therefore, the frequency of the compressor 1 is reduced to the minimum rotational speed. Is more preferable. That is, when the three-way valve 2 is switched to the bypass circuit 9 for the first time after the defrosting operation is started, the frequency of the compressor 1 is reduced to the minimum rotational speed.

  Through steps S11 to S13, the discharge gas from the compressor 1 flows through the evaporator 5 and the tray pipe 8, and the temperatures of the evaporator 5 and the tray pipe 8 rise (see FIG. 13).

Next, the controller 31 checks the temperature of the evaporator 5 detected by the evaporator temperature sensor 32 and the temperature of the tray 19 detected by the tray temperature sensor 33. Then, it is determined whether or not the temperature of the evaporator 5 is equal to or higher than Te ° C. and the temperature of the tray 19 is equal to or higher than Tt ° C. (step S14). Here, Te and Tt are values equal to or higher than 0 ° C., and the temperatures set for the evaporator temperature sensor 32 and the tray temperature sensor 33 to detect that the frost of the tray 19 and the evaporator 5 has been reliably melted, respectively. It is.
“Tt” corresponds to “first predetermined temperature” in the present invention.
“Te” corresponds to “second predetermined temperature” in the present invention.

When the temperature of the evaporator 5 is lower than Te ° C. or the temperature of the tray 19 is lower than Tt ° C. (No in Step S14), the three-way valve 2 is intermittently switched between the bypass circuit 9 and the main circuit 6 (Step S15). . On the other hand, when the temperature of the evaporator 5 is equal to or higher than Te ° C. and the temperature of the tray 19 is equal to or higher than Tt ° C. (Yes in step S14), the process proceeds to the evaporator cooling step (STEP 2).
When the three-way valve 2 is intermittently switched between the main circuit 6 and the bypass circuit 9, the control unit 31 operates so that the switching time on the bypass circuit 9 side is longer than the switching time on the main circuit 6 side (FIG. 13).

[Evaporator cooling process]
The control unit 31 controls the three-way valve driving means 201 to switch the three-way valve 2 from the bypass circuit 9 to the main circuit 6 (step S21). The control unit 31 changes the frequency of the compressor 1 to β (step S22). Here, the frequency β of the compressor 1 is a frequency lower than the frequency α, and is a value set for cooling the evaporator 5 warmed in the defrosting operation before shifting to the normal operation, Although the evaporator 5 is cooled as soon as possible, since the evaporator fan 23 is stopped, it is preferable to set the frequency β of the compressor 1 so large that the low pressure does not decrease too much.
“Frequency β” corresponds to “second rotational speed” in the present invention.

  Through the steps S21 and S22, the refrigerant having a low temperature and low pressure in the capillary 4 flows through the evaporator 5 and the tray pipe 8, and the temperatures of the evaporator 5 and the tray pipe 8 are lowered (see FIG. 13).

Next, the control unit 31 determines whether or not the temperature of the evaporator 5 detected by the evaporator temperature sensor 32 is equal to or lower than Te2 ° C. Here, Te2 is a value equal to or lower than 0 ° C., and is a temperature set for detecting by the evaporator temperature sensor 32 that the evaporator 5 has been sufficiently cooled.
“Te” corresponds to “second predetermined temperature” in the present invention.

  When the temperature of the evaporator 5 becomes equal to or lower than Te2 ° C. (Yes in Step S23), the control unit 31 ends the defrosting operation (Step S24). After the defrosting operation is completed, the control unit 31 controls the fan motor 231 to operate the evaporator fan 23 and controls the compressor motor 101 to set the frequency of the compressor 1 to the normal operation state and perform the normal operation (cooling operation). (STEP 3).

  In the control example described above, the tray 19 and the evaporator 5 are simultaneously defrosted. However, when the frost of the evaporator 5 falls on the tray 19, the temperature rise of the tray 19 is delayed. In consideration of this, a more preferable control operation will be described with reference to FIGS. 14 and 15.

FIG. 14 is another control flowchart of the refrigerator-freezer according to Embodiment 1 of the present invention.
FIG. 15 is a control time chart corresponding to the control flow of FIG.
Hereinafter, based on each step of FIG. 14, it demonstrates with reference to FIG.
The defrosting operation based on the control flow of FIG. 14 includes a tray / evaporator defrosting step (STEP 1), a tray defrosting step (STEP 12), and an evaporator cooling step (STEP 2). Further, after the defrosting operation is completed, the operation is shifted to the normal operation (STEP 3).

[Tray / evaporator defrosting process]
The operations in steps S11 to S13 and S15 are the same as the control shown in FIG.
Instead of the operation in step S14, the control unit 31 determines whether or not the temperature of the evaporator 5 is equal to or higher than Te ° C. (step S16). Here, Te ° C. is a value equal to or higher than 0 ° C., and is a temperature set for the evaporator temperature sensor 32 to detect that the defrosting of the evaporator 5 has been completed with certainty. As described above, since the frost in the evaporator 5 may fall on the tray 19, the temperature rises when the frost in the evaporator 5 disappears. After the temperature of the evaporator 5 becomes 0 ° C. or higher, an operation for melting the frost that has fallen on the tray 19 is required.

  When the temperature of the evaporator 5 becomes equal to or higher than Te ° C. (Yes in Step S16), the process proceeds to the tray defrosting step (STEP 12).

[Tray defrosting process]
The control unit 31 changes the frequency of the compressor 1 to γ (step S121). Here, the frequency γ of the compressor 1 takes a value necessary for melting the frost of the evaporator 5 dropped on the tray 19, but the tray pipe 8 has a smaller area than the evaporator 5, and the frequency value is If it is larger, the evaporator 5 will be heated more than the tray pipe 8, so a value smaller than the frequency α is desirable.
The “frequency γ” corresponds to the “third rotational speed” in the present invention.

  Further, the control unit 31 determines whether or not the temperature of the tray 19 is equal to or higher than Tt ° C. (step S122). Here, Tt ° C. is a value equal to or higher than 0 ° C., and is a temperature set in order for the tray temperature sensor 33 to detect that the frost on the tray 19 has been reliably melted.

  When the temperature of the tray 19 is lower than Tt ° C. (No in Step S122), the three-way valve 2 is intermittently switched between the bypass circuit 9 and the main circuit 6 as in Step S15 (Step S123). On the other hand, when the temperature of the tray 19 is equal to or higher than Tt ° C. (Yes in step S122), the process proceeds to the evaporator cooling step (STEP 2).

[Evaporator cooling process]
The operations in steps S21 to S24 are the same as the control shown in FIG.
Note that the frequency β of the compressor 1 set in step S22 is a frequency lower than the frequency α, and is set to cool the evaporator 5 warmed in the defrosting operation before shifting to the normal operation. It is a value that is larger than the frequency γ of the compressor 1 in order to cool the evaporator 5 as soon as possible. At this time, since the evaporator fan 23 is stopped, the frequency β of the compressor 1 is preferably set to a large value so that the low pressure does not decrease too much.

  Note that the evaporator cooling step (STEP 2) in the control flow of FIG. 12 and FIG. 14 described above is provided for cooling the evaporator 5. For this reason, in the above-described evaporator cooling process, the control unit 31 replaces the determination (S23) when the temperature of the evaporator 5 becomes equal to or lower than Te2 when a predetermined time has elapsed from the start of the evaporator cooling process. The operation of the evaporator fan 23 may be resumed and the defrosting operation may be terminated. The evaporator 5 can also be cooled by such an operation.

As described above, in the present embodiment, the tray pipe 8 is installed upstream of the evaporator 5 in the air passage of the cooling chamber 17 and in the vicinity of the tray 19. For this reason, at the time of cooling operation of a refrigerator-freezer, a part of the water | moisture content of the air which flows into the evaporator 5 can be made to frost on the tray piping 8, and the amount of frost formation to the evaporator 5 can be reduced. Therefore, the time for the defrosting operation can be shortened, and the cooling operation time can be lengthened. Therefore, the power consumption amount at the time of defrosting operation can be reduced, and the rise in the internal temperature due to the defrosting operation can be suppressed.
Further, in the defrosting operation, the frost frosted on the tray 19 and the evaporator 5 is efficiently processed with the discharge gas (hot gas) from the compressor 1, so that the defrosting time is shortened and energy is saved. The rise of the internal temperature can be suppressed and the quality of the food can be kept good.

Further, the three-way valve 2 serving as switching means is provided in a pipe connecting the capillary 4 and the tray pipe 8. That is, the three-way valve 2 is arranged on the low pressure side. For this reason, even if it is a case where a valve aperture is small, a pressure loss can be reduced compared with the case where it arrange | positions to a high voltage | pressure side. Therefore, switching means having a small valve diameter can be used, and the device can be miniaturized.
Further, the three-way valve 2 is intermittently switched between the main circuit 6 and the bypass circuit 9 during the defrosting operation. For this reason, the state where the main circuit 6 is closed does not continue, and the liquefaction (stagnation) of the refrigerant in the condenser 3 can be reduced. Therefore, the amount of refrigerant necessary for the defrosting operation can be passed through the bypass circuit 9, and the defrosting operation capable of obtaining sufficient ability to melt the frost is possible.

The defrosting operation includes a tray / evaporator defrosting step and an evaporator cooling step. For this reason, the frost on the tray 19 and the evaporator 5 can be melted in the tray / evaporator defrosting process, and the evaporator 5 can be cooled in the evaporator cooling process. Therefore, it can prevent that the heat | fever of the evaporator 5 heated at the time of a defrost operation is thermally radiated in the store | warehouse | chamber. Therefore, the rise in the internal temperature can be suppressed and the quality of the food can be kept good.
The defrosting operation includes a tray / evaporator defrosting process, a tray defrosting process, and an evaporator cooling process. For this reason, in addition to the above effect, even if the frost of the evaporator 5 falls on the tray 19 and the temperature rise of the tray 19 becomes slow, the frost dropped on the tray 19 can be melted.

Embodiment 2. FIG.
In the first embodiment, the form in which the bypass circuit 9 is put into the refrigerator from the back surface of the cooling chamber 17 has been described. In the second embodiment, a mode in which the bypass circuit 9 is inserted into the cooling chamber 17 from the drain port 20 will be described.
The same parts as those in the first embodiment are denoted by the same reference numerals.
The operation of the defrosting operation is the same as that in the first embodiment.

FIG. 16 is a rear view of the refrigerator-freezer according to Embodiment 2 of the present invention.
FIG. 17 is a front view of cooling chamber 17 of the refrigerator-freezer according to Embodiment 2 of the present invention.
As shown in FIGS. 16 and 17, a machine room 10 is provided on the lower side of the back surface of the refrigerator-freezer main body. In the machine room 10, there are a compressor 1, a machine room fan 11 for forcibly air cooling the shell of the compressor 1, a forced air cooling condenser 3 a such as a heat exchanger constituting the condenser 3, a drain pan 13, and a dryer 14. Is included. The piping of the main circuit 6 is connected to the forced air-cooled condenser 3a from the compressor 1, and after exiting the forced air-cooled condenser 3a, the inside of the steel plate 15 of the refrigerator which is a natural heat dissipation condenser constituting the condenser 3 Connect to the pipe installed in. The three-way valve 2 is installed in the cooling chamber 17. An evaporator 5 is disposed in the center of the cooling chamber 17. In addition, an evaporator fan 23 that blows the air cooled by the evaporator 5 into the cabinet is disposed above the evaporator 5. A tray 19 is disposed below the evaporator 5. The main circuit 6 entering from the hole 18 at the cooling chamber inlet of the cooling chamber 17 passes through the tray pipe 8 arranged on the tray 19 from the three-way valve 2 and is connected to the evaporator 5.

  On the other hand, the bypass circuit 9 branches from between the compressor 1 and the forced air-cooled condenser 3 a and then passes through the drain hose 21 and enters the cooling chamber 17 from the drain port 20 of the tray 19. The bypass circuit 9 entered from the drain outlet 20 of the tray 19 passes through the tray 19 and is connected to the three-way valve 2. The tray pipe 8 is bent along the tray 19.

18 to 20 are top views of the tray piping 8 of the refrigerator-freezer according to Embodiment 2 of the present invention.
As shown in FIG. 18, the tray 19 has a drain outlet 20 at the center, and the bypass circuit 9 enters the cabinet from the drain outlet 20 and is connected to the main circuit 6, and then draws a character “NO”. Thus, the shape along the tray 19 is used. If the pipe is copper with an outer diameter of 4 mm and a wall thickness of about 0.3 mm, the minimum radius of bending of the pipe is about 15 mm and the depth of the tray 19 is as narrow as 60 to 80 mm. In the case of the character, it is possible to arrange the pipes on the tray 19 in general without overlapping the pipes, and the end point of the tray pipe 8 becomes the corner of the tray 19 and the connection to the inlet of the evaporator 5 becomes easy. Further, when a part of the character “no” is meandered as shown in FIG. 19, the heat transfer area increases and the defrosting time can be shortened.

  When the drain port 20 is open at the center of the tray 19, as shown in FIG. 4, the bottom surface of the tray 19 has a pointed downward shape so that drain is collected at the center. For this reason, if the tray pipe 8 has a butterfly shape or an 8-shaped shape along the corner of the tray 19 as shown in FIG. In addition, water droplets easily flow to the drain port 20.

  As described above, in the present embodiment, at least a part of the piping of the bypass circuit 9 enters the cooling chamber 17 through the drain hose 21 through the drain hose 21 and is connected to the three-way valve 2. For this reason, the piping path of the bypass circuit 9 can be shortened. Moreover, the drain port 20 and its vicinity can be heated by piping of the bypass circuit 9, and it can reduce that the drain port 20 is plugged up with frost. Therefore, it is possible to prevent the drain from overflowing from the tray 19 and leaking into the cabinet.

Embodiment 3 FIG.
In the first and second embodiments, the mode in which the bypass circuit 9 enters the evaporator 5 via the tray pipe 8 has been described. In the third embodiment, a mode in which a second bypass circuit for flowing hot gas directly to the evaporator 5 is also described.
The same parts as those in the first embodiment are denoted by the same reference numerals.

FIG. 21 is a circuit diagram of a refrigeration cycle in Embodiment 3 of the present invention.
As shown in FIG. 21, in addition to the configuration of the first embodiment (FIG. 1), the pipe branching from the pipe connecting the compressor 1 and the condenser 3 to the pipe connecting the tray pipe 8 and the evaporator 5 The second bypass circuit 9b, the throttle mechanism 7A for opening and closing the refrigerant flow path of the bypass circuit 9, and the throttle mechanism 7B for opening and closing the refrigerant flow path of the second bypass circuit 9b.
The “diaphragm mechanism 7A” and “diaphragm mechanism 7B” correspond to “opening / closing means” in the present invention.

FIG. 22 is a rear view of the refrigerator-freezer according to Embodiment 3 of the present invention.
As shown in FIG. 22, a machine room 10 is provided on the lower side of the back surface of the refrigerator-freezer main body. In the machine room 10, there are a compressor 1, a machine room fan 11 for forcibly air cooling the shell of the compressor 1, a forced air cooling condenser 3 a such as a heat exchanger constituting the condenser 3, a drain pan 13, and a dryer 14. Is included. The piping of the main circuit 6 is connected to the forced air-cooled condenser 3a from the compressor 1, and after exiting the forced air-cooled condenser 3a, the inside of the steel plate 15 of the refrigerator which is a natural heat dissipation condenser constituting the condenser 3 Connect to the pipe installed in. On the other hand, the bypass circuit 9 and the second bypass circuit 9b branch from between the compressor 1 and the forced air-cooled condenser 3a, respectively, then pass through the inside of the heat insulating wall 16 on the back of the refrigerator, and enter the refrigerator through the hole 18 at the cooling chamber inlet. Enter inside.

FIG. 23 is a front view of cooling chamber 17 of the refrigerator-freezer according to Embodiment 3 of the present invention.
As shown in FIG. 23, the evaporator 5 is disposed in the center of the cooling chamber 17. In addition, an evaporator fan 23 that blows the air cooled by the evaporator 5 into the cabinet is disposed above the evaporator 5. A tray 19 is disposed below the evaporator 5. The main circuit 6 entering from the hole 18 at the cooling chamber inlet of the cooling chamber 17 passes through the tray pipe 8 arranged on the tray 19 from the three-way valve 2 and is connected to the evaporator 5. On the other hand, the bypass circuit 9 entering from the hole 18 at the cooling chamber inlet is connected to the three-way valve 2. Further, the second bypass circuit 9b entered from the hole 18 at the cooling chamber inlet is directly connected to the inlet of the evaporator 5.

  Note that one or both of the bypass circuit 9 and the second bypass circuit 9b may be inserted into the cooling chamber 17 from the drain port 20 as in the second embodiment. An example is shown in FIGS.

FIG. 24 is a rear view of another refrigerator-freezer according to Embodiment 3 of the present invention.
FIG. 25 is a front view of the cooling chamber 17 of the refrigerator-freezer of FIG.
In the example shown in FIG. 24, the bypass circuit 9 passes through the drain hose 21 through the throttle mechanism 7A, enters the cooling chamber 17 from the drain port 20, and is connected to the three-way valve 2. The second bypass circuit 9b passes through the inside of the heat insulating wall 16 on the back of the refrigerator through the throttle mechanism 7B and enters the cooling chamber 17 from the hole 18 at the cooling chamber inlet. Then, the second bypass circuit 9b entered from the hole 18 at the cooling chamber inlet is directly connected to the inlet of the evaporator 5.

  Next, the control operation of the defrosting operation in the present embodiment will be described. The normal cooling operation is the same as that in the first embodiment.

[Control action]
FIG. 26 is a block diagram showing the configuration of the control system in the third embodiment of the present invention.
As shown in FIG. 26, the control system in the present embodiment replaces the diaphragm mechanism 7 and diaphragm mechanism driving means 701 in the first embodiment (FIG. 11), and includes a diaphragm mechanism 7A and a diaphragm mechanism driving means 7A1. An aperture mechanism 7B and an aperture mechanism driving means 7B1 are provided.
Other configurations are the same as those in FIG. 11, and the same portions are denoted by the same reference numerals.

  In the defrosting operation, when the frosting amount of the evaporator 5 is large, frost falls from the evaporator 5 to the tray 19, so that the throttle mechanism 7 </ b> A is opened and the throttle mechanism 7 </ b> B is closed, so that Embodiment 1 or The same control as that of the second embodiment is performed. On the other hand, when the amount of frost formation in the evaporator 5 is small, that is, when the frost is completely melted in the evaporator 5, the temperature rise of the tray 19 becomes large, and wasteful energy is consumed on the tray pipe 8 side. It is more efficient to flow hot gas only in the vessel 5. Hereinafter, the operation of the control unit 31 when hot gas is allowed to flow only to the evaporator 5 will be described.

  In addition, although it is about some judgment of the amount of frost formation of the said evaporator 5, this is the predetermined value (upper limit value) in which the temperature of the tray 19 detected by the tray temperature sensor 33 is 0 degreeC or more, for example in a defrost operation. ), The control unit 31 melts and the frost is hardly dropped because the amount of frost formation on the evaporator 5 is small, and the temperature of the tray 19 reaches the upper limit due to the hot gas flowing in the tray pipe. What is necessary is just to comprise so that it may judge. Alternatively, if the time from the start of the defrosting operation until the temperature of the tray 19 detected by the tray temperature sensor 33 reaches a predetermined value of 0 ° C. or higher is smaller than the predetermined value, the control unit 31 causes the evaporator 5 to form frost. Since the amount is small, there is almost no drop, and it may be determined that the temperature of the tray has reached the predetermined temperature or higher very quickly due to the hot gas flowing in the tray piping.

FIG. 27 is a control flowchart of the refrigerator-freezer according to Embodiment 3 of the present invention.
Hereinafter, a description will be given based on each step of FIG.
The defrosting operation based on the control flow of FIG. 27 includes a tray / evaporator defrosting step (STEP 1), an evaporator defrosting step (STEP 21), and an evaporator cooling step (STEP 2). Further, after the defrosting operation is completed, the operation is shifted to the normal operation (STEP 3).

[Tray / evaporator defrosting process]
When the defrosting operation is started, the control unit 31 controls the fan motor 231 to stop the operation of the evaporator fan 23 (step S11). The controller 31 controls the three-way valve driving means 201 to switch the three-way valve 2 so that the discharge gas of the compressor 1 flows to the bypass circuit 9 (step S12). The control unit 31 controls the diaphragm mechanism driving means 7A1 to open the diaphragm mechanism 7A, controls the diaphragm mechanism driving means 7B1 to close the diaphragm mechanism 7B, and closes the refrigerant flow path of the second bypass circuit 9b. The bypass circuit 9 is opened and the refrigerant is circulated (step S261). Next, the control part 31 controls the compressor motor 101, and changes the frequency of the compressor 1 to the frequency (alpha) at the time of defrosting (step S13). In general, during normal operation, the compressor 1 is operated at a lower frequency, so the frequency α during defrosting is greater than the frequency during normal operation. The defrosting time can be shortened by setting the value as large as possible in consideration of the current value limitation and the liquid back reliability to the compressor 1.
The “frequency α” corresponds to the “first rotational speed” in the present invention.

  When the three-way valve 2 is switched to the bypass circuit 9, the high and low pressures approach a pressure equalization state, and the refrigerant suddenly flows into the bypass circuit 9 to generate refrigerant sound. Therefore, in order to solve this problem, it is preferable to reduce the frequency of the compressor 1 or stop the compressor 1 before switching the three-way valve 2 to the bypass circuit 9 in step S12. At this time, if the compressor 1 is stopped, it is necessary to ensure the time until restart for reliability, and it takes time for defrosting. Therefore, the frequency of the compressor 1 is reduced to the minimum rotational speed. Is more preferable. That is, when the three-way valve 2 is switched to the bypass circuit 9 for the first time after the defrosting operation is started, the frequency of the compressor 1 is reduced to the minimum rotational speed.

  Through steps S11 to S13, the discharge gas from the compressor 1 flows through the evaporator 5 and the tray pipe 8, and the temperatures of the evaporator 5 and the tray pipe 8 rise.

Next, the controller 31 checks the temperature of the evaporator 5 detected by the evaporator temperature sensor 32 and the temperature of the tray 19 detected by the tray temperature sensor 33. Then, it is determined whether or not the temperature of the evaporator 5 is equal to or lower than Te ° C. and the temperature of the tray 19 is equal to or higher than Tt ° C. (step S262). Here, Te and Tt are values equal to or higher than 0 ° C., and the temperatures set for the evaporator temperature sensor 32 and the tray temperature sensor 33 to detect that the frost of the tray 19 and the evaporator 5 has been reliably melted, respectively. It is. In step S262, it may be determined only whether the temperature of the tray 19 is equal to or higher than Tt ° C.
“Tt” corresponds to “first predetermined temperature” in the present invention.
“Te” corresponds to “second predetermined temperature” in the present invention.

When the temperature of the evaporator 5 is higher than Te ° C. or when the temperature of the tray 19 is lower than Tt ° C. (No in Step S262), the three-way valve 2 is intermittently switched between the bypass circuit 9 and the main circuit 6 (Step S262). S15). On the other hand, when the temperature of the evaporator 5 is equal to or lower than Te ° C. and the temperature of the tray 19 is equal to or higher than Tt ° C. (Yes in step S262), the amount of frost formation on the evaporator 5 is small, so It is determined that the drop has almost disappeared and the temperature of the tray 19 has increased due to the hot gas flowing in the tray pipe 8, and the process proceeds to the evaporator defrosting step (STEP 21).
When the three-way valve 2 is intermittently switched between the main circuit 6 and the bypass circuit 9, the control unit 31 operates so that the switching time on the bypass circuit 9 side is longer than the switching time on the main circuit 6 side.

  Note that step S262 determines that the amount of frost formation in the evaporator 5 is small. For this reason, in the tray / evaporator defrosting process, the controller 31 performs the time from the start of the defrosting operation until the temperature of the tray 19 reaches Tt after the temperature of the tray 19 becomes Tt or higher after step S13. When it is smaller than the predetermined value, the process proceeds to the evaporator defrosting step (STEP 21), the time from the start of the defrosting operation until the temperature of the tray 19 reaches Tt is equal to or greater than the predetermined value, and the temperature of the evaporator 5 is equal to or higher than Te. When it becomes, you may make it transfer to an evaporator cooling process (STEP2).

[Evaporator defrosting process]
The control unit 31 controls the throttle mechanism driving means 7A1 to close the throttle mechanism 7A, controls the throttle mechanism driving means 7B1 to open the throttle mechanism 7B, closes the refrigerant flow path of the bypass circuit 9, and The bypass circuit 9b is opened to allow the refrigerant to flow (step S263). As a result, the hot gas stops flowing into the tray pipe 8 and flows only into the evaporator 5.

  Next, the controller 31 checks the temperature of the evaporator 5 detected by the evaporator temperature sensor 32 and the temperature of the tray 19 detected by the tray temperature sensor 33. Then, it is determined whether or not the temperature of the evaporator 5 is Te ° C. or higher and the temperature of the tray 19 is Tt ° C. or higher (Step S264). In step S264, it may be determined only whether the temperature of the evaporator 5 is equal to or higher than Te ° C.

  When the temperature of the evaporator 5 is lower than Te ° C. or the temperature of the tray 19 is lower than Tt ° C. (No in Step S264), the three-way valve 2 is intermittently switched between the bypass circuit 9 and the main circuit 6 (Step S265). . On the other hand, when the temperature of the evaporator 5 is equal to or higher than Te ° C. and the temperature of the tray 19 is equal to or higher than Tt ° C. (Yes in step S264), it is determined that the frost in the evaporator 5 has melted, and the evaporator cooling process ( Move to STEP 2). When the three-way valve 2 is intermittently switched between the main circuit 6 and the bypass circuit 9, the control unit 31 operates so that the switching time on the bypass circuit 9 side is longer than the switching time on the main circuit 6 side.

[Evaporator cooling process]
The control unit 31 controls the three-way valve driving means 201 to switch the three-way valve 2 from the bypass circuit 9 to the main circuit 6 (step S21). Further, the control unit 31 controls the aperture mechanism driving unit 7B1 to open the aperture mechanism 7A. Next, the control unit 31 changes the frequency of the compressor 1 to β (step S22). Here, the frequency β of the compressor 1 is a frequency lower than the frequency α, and is a value set for cooling the evaporator 5 warmed in the defrosting operation before shifting to the normal operation, Although the evaporator 5 is cooled as soon as possible, since the evaporator fan 23 is stopped, it is preferable to set the frequency β of the compressor 1 so large that the low pressure does not decrease too much.
“Frequency β” corresponds to “second rotational speed” in the present invention.

  Through the steps S21 and S22, the refrigerant having a low temperature and low pressure in the capillary 4 flows through the evaporator 5 and the tray pipe 8, and the temperatures of the evaporator 5 and the tray pipe 8 are lowered.

Next, the control unit 31 determines whether or not the temperature of the evaporator 5 detected by the evaporator temperature sensor 32 is equal to or lower than Te2 ° C. Here, Te2 is a value equal to or lower than 0 ° C., and is a temperature set for detecting by the evaporator temperature sensor 32 that the evaporator 5 has been sufficiently cooled.
“Te” corresponds to “second predetermined temperature” in the present invention.

  When the temperature of the evaporator 5 becomes equal to or lower than Te2 ° C. (Yes in Step S23), the control unit 31 ends the defrosting operation (Step S24). After completion of the defrosting operation, the control unit 31 controls the fan motor 231 to operate the evaporator fan 23 and controls the compressor motor 101 to set the frequency of the compressor 1 to the normal operation state and perform the normal operation (cooling operation). (STEP 3).

  Note that the evaporator cooling step (STEP 2) in the control flow of FIG. 27 described above is provided for cooling the evaporator 5. For this reason, in the above-described evaporator cooling process, the control unit 31 replaces the determination (S23) when the temperature of the evaporator 5 becomes equal to or lower than Te2 when a predetermined time has elapsed from the start of the evaporator cooling process. The operation of the evaporator fan 23 may be resumed and the defrosting operation may be terminated. The evaporator 5 can also be cooled by such an operation.

  As described above, in the present embodiment, since the second bypass circuit 9 b that flows hot gas directly to the evaporator 5 is provided, when the amount of frost formation on the evaporator 5 is small and frost does not fall on the tray 19. The hot gas can be supplied only to the evaporator 5. Thereby, the temperature rise of the tray 19 becomes large, and it can be reduced that wasted energy is consumed on the tray pipe 8 side. Therefore, the heat of hot gas can be efficiently used for defrosting.

Embodiment 4 FIG.
In the first to third embodiments, as illustrated in FIG. 4, the drain port 20 is provided at the center of the tray 19, and the tray 19 is recessed downward toward the center. In the fourth embodiment, a description will be given of a form in which the tray 19 is flat (flat).

FIG. 28 is a front view of cooling chamber 17 of the refrigerator-freezer according to Embodiment 4 of the present invention.
The tray 19 according to the fourth embodiment has a flat bottom surface, is provided with a drain port 20 at an end of the bottom surface, and is disposed so that the bottom surface of the tray 19 is inclined toward the drain port 20. For example, as shown in FIG. 28, the floor surface of the tray 19 is inclined obliquely so that the left rear surface is the lowest.

With such a configuration, when the tray pipe 8 is bent as shown in FIGS. 5 to 8 and FIGS. 18 to 20, for example, the floor surface of the tray 19 can be easily arranged.
In the example of FIG. 28, the bypass circuit 9 is put into the cabinet through the hole 18 at the cooling chamber inlet. However, the bypass circuit 9 may be put into the cabinet through the drain outlet 20 as in the second embodiment. Is applicable to both FIG. 1 and FIG. The inclination of the tray 19 is not limited to the left rear surface, and the tray 19 may be inclined so that one corner on the left and right sides is lowest.

Embodiment 5 FIG.
In the above-described first to fourth embodiments, the case where the tray pipe 8 is placed along the upper surface of the tray 19 has been described. In the fifth embodiment, an embodiment in which the tray pipe 8 is provided on the lower surface of the tray 19 will be described.

FIG. 29 is a front view of cooling chamber 17 of the refrigerator-freezer according to Embodiment 5 of the present invention.
For example, as shown in FIG. 29, the tray pipe 8 in the fifth embodiment is arranged on the lower surface of the tray 19.
Even with such a configuration, the same effects as those of the first to fourth embodiments can be obtained. Furthermore, the bottom surface of the tray 19 and the tray pipe 8 are brought into contact with each other, whereby the tray 19 can be uniformly warmed and the residual frost can be melted.

  In addition, by comprising tray 19 with an aluminum steel plate, the heat conductivity from tray piping 8 is high, and defrosting efficiency can be improved more.

  Note that the tray pipe 8 may be installed outside the drain port 20 and along the drain hose 21. The drain hose 21 may be bent from the positional relationship with the drain pan 13 or may have a structure in which a water reservoir is formed by meandering up and down in order to prevent air flow. It may be difficult to install the cooling chamber 17 in the cooling chamber 17. Even in such a case, by arranging the drain hose 21 along the outside, the shape of the drain hose 21 becomes free and the production efficiency can be improved.

Embodiment 6 FIG.
The discharge pipe of the compressor 1 is routed in the shell. The shell is forcibly cooled by a machine room fan 11 from the outside. For this reason, the heat of the hot gas discharged from the compressor 1 is dissipated from the shell. For this reason, the heat which can be utilized for defrosting is exhausted by the machine room 10.
For this reason, in the sixth embodiment, during the defrosting operation, the operation of the machine room fan 11 is stopped, or the rotation speed of the machine room fan 11 is lower than the rotation speed during the cooling operation (operation other than the defrosting operation). Let Thereby, the heat radiated from the shell of the compressor 1 can be reduced, and the heat used for defrosting can be increased. Therefore, the heat of hot gas can be efficiently used for defrosting.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Three-way valve, 3 Condenser, 3a Forced air cooling condenser, 4 Capillary tube, 5 Evaporator, 6 Main circuit, 7 Throttle mechanism, 7A Throttle mechanism, 7B Throttle mechanism, 701 Throttle mechanism drive means, 7A1 Throttle mechanism Drive means, 7B1 throttle mechanism drive means, 8 tray piping, 9 bypass circuit, 9b second bypass circuit, 10 machine room, 11 machine room fan, 13 drain pan, 14 dryer, 15 steel plate, 16 heat insulation wall, 17 cooling room, 18 Cooling chamber inlet hole, 19 Tray, 20 Drain port, 21 Drain hose, 22 Suction pipe, 23 Evaporator fan, 31 Control unit, 32 Evaporator temperature sensor, 33 Tray temperature sensor, 101 Compressor motor, 201 Three-way valve Driving means, 231 fan motor.

Claims (25)

A compressor, a condenser, a decompression means, a tray pipe, and an evaporator are connected in order by a pipe, and a main circuit for circulating the refrigerant;
A bypass circuit that branches from a pipe that connects the compressor and the condenser of the main circuit, and leads to a pipe that connects the pressure reducing means of the main circuit and the tray pipe;
Switching means for switching the refrigerant flow path to the main circuit or the bypass circuit;
A cooling chamber in which an air passage for accommodating the evaporator and the tray pipe and circulating the air in the cabinet is formed;
A tray provided below the evaporator and receiving water and frost falling from the evaporator;
The tray piping is
A refrigerator-freezer, wherein the refrigerator is installed in the vicinity of the tray, upstream of the evaporator in the air path. The switching means is
The refrigerator-freezer according to claim 1, wherein the refrigerator is configured by a three-way valve and is provided in a pipe connecting the decompression unit and the tray pipe. An evaporator fan that sends air to the evaporator;
An evaporator temperature sensor for detecting the temperature of the evaporator;
A tray temperature sensor for detecting the temperature of the tray;
A controller for controlling the operation of the compressor, the switching means, and the evaporator fan,
The controller is
A defrosting operation including a tray / evaporator defrosting step and an evaporator cooling step is executed,
In the tray / evaporator defrosting step, the operation of the evaporator fan is stopped, the switching means is switched to the bypass circuit, the temperature of the tray is equal to or higher than a first predetermined temperature, and the temperature of the evaporator When the temperature becomes equal to or higher than the second predetermined temperature, the process proceeds to the evaporator cooling step,
The evaporator cooling step includes switching the switching means to the main circuit, and restarting the operation of the evaporator fan when the temperature of the evaporator becomes equal to or lower than a third predetermined temperature. The refrigerator-freezer of 1 or 2. The controller is
The refrigerator / freezer according to claim 3, wherein, in the tray / evaporator defrosting step, the switching means is intermittently switched between the main circuit and the bypass circuit. The controller is
In the tray / evaporator defrosting step, the compressor is operated at a first rotational speed,
5. The refrigerator-freezer according to claim 3, wherein in the evaporator cooling step, the compressor is operated at a second rotational speed lower than the first rotational speed. An evaporator fan that sends air to the evaporator;
An evaporator temperature sensor for detecting the temperature of the evaporator;
A tray temperature sensor for detecting the temperature of the tray;
A controller for controlling the operation of the compressor, the switching means, and the evaporator fan,
The controller is
A defrosting operation including a tray / evaporator defrosting process, a tray defrosting process, and an evaporator cooling process;
In the tray / evaporator defrosting step, the operation of the evaporator fan is stopped, the switching means is switched to the bypass circuit, and the tray removal is performed when the temperature of the evaporator becomes a second predetermined temperature or more. Move to frost process,
In the tray defrosting step, when the temperature of the tray becomes a first predetermined temperature or more, the process proceeds to the evaporator cooling step,
The evaporator cooling step includes switching the switching means to the main circuit, and restarting the operation of the evaporator fan when the temperature of the evaporator becomes equal to or lower than a third predetermined temperature. The refrigerator-freezer of 1 or 2. The controller is
The refrigerator / freezer according to claim 6, wherein in the tray / evaporator defrosting step and the tray defrosting step, the switching means is intermittently switched between the main circuit and the bypass circuit. The controller is
In the tray / evaporator defrosting step, the compressor is operated at a first rotational speed,
In the tray defrosting step, the compressor is operated at a third rotational speed lower than the first rotational speed,
8. The refrigerator-freezer according to claim 6, wherein in the evaporator cooling step, the compressor is operated at a second rotational speed lower than the first rotational speed and higher than the third rotational speed. . A second bypass circuit branched from a pipe connecting the compressor and the condenser and reaching a pipe connecting the tray pipe and the evaporator;
Opening and closing means for opening and closing the refrigerant flow paths of the bypass circuit and the second bypass circuit, respectively;
An evaporator fan that sends air to the evaporator;
An evaporator temperature sensor for detecting the temperature of the evaporator;
A tray temperature sensor for detecting the temperature of the tray;
A controller that controls operations of the compressor, the switching unit, the evaporator fan, and the opening and closing unit;
The controller is
Performing a defrosting operation including a tray / evaporator defrosting process, an evaporator defrosting process, and an evaporator cooling process;
In the tray / evaporator defrosting step, the operation of the evaporator fan is stopped, the switching means is switched to the bypass circuit, the refrigerant flow path of the second bypass circuit is closed, and the bypass circuit is opened. When the temperature of the tray becomes equal to or higher than the first predetermined temperature, the process proceeds to the evaporator defrosting process,
In the evaporator defrosting step, when the refrigerant flow path of the bypass circuit is closed, the second bypass circuit is opened to circulate the refrigerant, and the temperature of the evaporator becomes equal to or higher than a second predetermined temperature. , Transition to the evaporator cooling step,
The evaporator cooling step includes switching the switching means to the main circuit, and restarting the operation of the evaporator fan when the temperature of the evaporator becomes equal to or lower than a third predetermined temperature. The refrigerator-freezer of 1 or 2. The controller is
In the tray / evaporator defrosting step, the operation of the evaporator fan is stopped, the switching means is switched to the bypass circuit, the refrigerant flow path of the second bypass circuit is closed, and the bypass circuit is opened. Circulating the refrigerant, the tray temperature is equal to or higher than a first predetermined temperature, and the time from the start of the defrosting operation until the tray temperature reaches the first predetermined temperature is smaller than a predetermined value, Move to the evaporator defrosting process,
When the time from the start of the defrosting operation until the temperature of the tray reaches the first predetermined temperature is not less than a predetermined value, and the temperature of the evaporator becomes not less than the second predetermined temperature, the cooling process of the evaporator is performed. The refrigerator-freezer according to claim 9, wherein the refrigerator is transferred. The controller is
The refrigerator-freezer according to claim 9 or 10, wherein in the tray / evaporator defrosting step and the evaporator defrosting step, the switching means is intermittently switched between the main circuit and the bypass circuit. The controller is
In the tray / evaporator defrosting step and the evaporator defrosting step, the compressor is operated at a first rotational speed,
The refrigerator-freezer according to any one of claims 9 to 11, wherein in the evaporator cooling step, the compressor is operated at a second rotational speed lower than the first rotational speed. The first predetermined temperature and the second predetermined temperature are temperatures of 0 ° C. or higher,
13. The refrigerator-freezer according to claim 3, wherein the third predetermined temperature is a temperature of 0 ° C. or lower. The controller is
The frequency of the compressor is reduced to the minimum number of revolutions when the switching means is switched to the bypass circuit for the first time after the defrosting operation is started. Freezer refrigerator. The controller is
In the evaporator cooling step, instead of determining when the temperature of the evaporator is equal to or lower than a third predetermined temperature, the evaporator fan is operated when a predetermined time has elapsed since the start of the evaporator cooling step. The refrigerator-freezer according to any one of claims 3 to 14, wherein the refrigerator is restarted. The controller is
The switching time on the bypass circuit side is longer than the switching time on the main circuit side when the switching means is intermittently switched between the main circuit and the bypass circuit. The refrigerator-freezer of any one. A machine room fan for cooling the compressor;
The controller is
The operation of the machine room fan is stopped during the defrosting operation, or the rotation speed of the machine room fan is made lower than the rotation speed during operation other than the defrosting operation. The refrigerator-freezer of Claim 1. The main circuit, and a refrigerator-freezer body that houses the bypass circuit,
The cooling chamber is provided on the inner back side of the refrigerator-freezer main body, and a hole through which a pipe connected to the evaporator enters the cooling chamber is formed on the inner wall.
At least a part of the piping of the bypass circuit passes through the inside of the heat insulating wall of the refrigerator-freezer body, and is connected to the switching means.
18. The refrigerator-freezer according to claim 1, wherein the switching unit is arranged inside a heat insulating wall of the refrigerator-freezer main body or in the cooling chamber. The tray includes a drain port for discharging water that has been dropped from the evaporator and water generated by melting of frost to the outside of the warehouse, and a drain hose extending downward from the drain port,
18. At least a part of piping of the bypass circuit enters the cooling chamber from the drain through the drain hose and is connected to the switching unit. The refrigerator-freezer of description. The tray includes a drain outlet that discharges water that has fallen from the evaporator and water generated by melting of frost to the outside of the warehouse,
20. The refrigerator-freezer according to claim 1, wherein the tray pipe is disposed so as to pass near the drain port or on the drain port. 21. The refrigeration according to claim 19 or 20, wherein the tray is provided with the drain outlet at substantially the center thereof, and the bottom surface of the tray is inclined so as to gradually become lower from the edge toward the drain outlet. refrigerator. The tray has a flat bottom surface, the drain port is provided at an end of the bottom surface, and the bottom surface of the tray is disposed so as to be inclined toward the drain port. Or the refrigerator-freezer of 20. The refrigerator tray according to any one of claims 1 to 22, wherein the tray pipe is disposed on an upper surface or a lower surface of the tray. The refrigerator tray according to any one of claims 1 to 23, wherein the tray pipe is formed to meander the upper surface or the lower surface of the tray. 25. The refrigerator-freezer according to claim 1, wherein the tray is made of an aluminum steel plate.

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