RU2231721C2 - Quick-freezing tunnel apparatus - Google Patents

Abstract

FIELD: food industry equipment, particularly for product storage, into which product surfaces are exposed to low-temperature air for product freezing.

SUBSTANCE: apparatus comprises heat-insulated body with conveying unit for product freezing and with low-temperature air inlet and outlet channels. Removable shield is obliquely located above conveying unit for air flow distribution onto product. Shield includes several sections with orifices. Inlet channel for low-temperature air has expansion part.

EFFECT: simplified structure, simplified operation, decreased power consumption, provision of ecologically safe and quick product freezing.

2 cl, 5 dwg

Description

The invention relates to refrigeration processing equipment, namely, freezers for freezing food products in contact with low-temperature air.

Known quick-freezing tunnel apparatus, consisting of a thermally insulated body, the working volume of which is divided into three freezing zones, where axial fans are installed in the first zone, a liquid collector for spraying through the nozzles of liquid refrigerant in the second and the third zone - temperature equalization by the thickness of the product. A transporting body is placed along the entire length of the casing, and a ventilation device is mounted on the end side of the casing on the product inlet side for suction of exhaust vapors of the refrigerant [RU, patent, 2113665, cl. F 25 D 13/00, 1994].

The disadvantages of the device include the fact that fans are used to direct nitrogen vapors to the pre-cooling zone, which complicates the design of the device.

The freezing tunnel apparatus (ASTA) for freezing food products includes a thermally insulated body, a transporting body mounted on a frame with supports, a refrigerant supply and discharge system, and also axial circulation fans with multidirectional rotation [g. “Refrigeration Business”, 2000, No. 2, pp. 32-33; g. “Chemical and oil and gas engineering”, 2002, No. 10, p.20-22].

The ASTA apparatus uses liquid nitrogen (-196 ° С) for freezing, which is supplied from the tank to the nozzles of the second zone of the device, the vapors generated during atomization of the liquid cryogen are fed into the first and third zones for cooling and temperature equalization according to the thickness of the product, respectively.

Such an apparatus has a number of disadvantages:

- the need for fans (3-5) depending on the performance of the apparatus for sending nitrogen vapors to the first zone, which complicates the design of the equipment;

- significant consumption of expensive liquid nitrogen, which, taking into account losses in the main pipeline from the tank to the apparatus, is about 1.5 kg per 1 kg of the frozen product;

- liquid nitrogen is sprayed onto the product located on the transporting organ from above, which does not provide uniform (symmetrical) heat transfer from all sides of the freezing object;

- the difficulty in operating such equipment with a refrigerant temperature (-196 ° C), requiring serious skills.

Closest to the proposed and selected as a prototype is an apparatus of the same design, but with the ability to use alternately liquid nitrogen, gaseous nitrogen and cold air as a refrigerant through control systems [RU, patent 2168123, cl. F 25 D 13/00, 2000].

The invention has the above disadvantages.

The use of low-temperature air as a refrigerant (-60 ...- 120 ° С) allows to significantly simplify the design of a three-zone quick-freezing apparatus.

The proposed invention is aimed at solving a technical problem, which consists in simplifying the design and operation of the apparatus while providing conditions for quick freezing and maintaining the quality of food products, as well as in preserving its energy consumption.

The technical problem of the invention is achieved by the fact that in the proposed apparatus, which is a thermally insulated casing, forming a tunnel chamber with a transporting body for freezing products, connected to a turbo-refrigerating machine through low-temperature air inlet and outlet channels, as well as a device for distributing and directing the incoming low-temperature air flow, new is that removable plugs are used to direct the distribution of the incoming low-temperature air flow , Collapsible, grid screen mounted obliquely to the conveying organ, wherein the low-temperature air introduced into the chamber is equipped with an expansion channel.

In this case, it is advisable to carry out the first section of the screen in the area of product unloading, since here the temperature of the frozen product is aligned.

In addition, it is advisable to arrange the screen sections in the chamber along the guide rails mounted on the inside of the chamber.

Figure 1 schematically shows a quick-freezing tunnel apparatus, a longitudinal section; figure 2 is the same, a top view; figure 3 is the same, end view; figure 4 shows sections of the screen: a - without holes, b, c, d, d - with holes of various configurations and layouts; figure 5 shows the guide rails for securing the screen.

The proposed apparatus consists of a thermally insulated housing 1, the working volume of which forms a chamber for freezing products. Along the entire length of the housing 1 there is a transporting body 2 mounted on a supporting frame 3, a knife 4 is mounted at the end of the transporting body 2 for removing products from the transporting body. The apparatus has a drive part 5 for the transporting body 2 and a drive part 6 for lifting the heat-insulated body 1, the frame 3 is mounted on the supports 7, and a pipe 8 is mounted on the front side of the body 1 from the product inlet side for supplying low-temperature air from the turbo-refrigerating machine. The pipe 8 is equipped with an expansion channel 9 for uniform distribution of air in the chamber. Inside the chamber above the transporting body 2, a removable screen 10 is rigidly mounted with an inclination towards the discharge of the product. The screen 10 is made of detachable sections with openings for creating low-temperature air flows and controlling its parameters. On the product inlet side, a device 11 is mounted for exhaust air suction back into the turbo-refrigeration machine; the apparatus is equipped with loading windows 12 and unloading 13 products.

It is advisable to tilt the screen 10 to perform from a set of sections: the first section (in the area of product discharge) is made without holes, and the rest with holes, depending on the length of the tunnel. Section made of stainless steel sheet thickness δ = 2 mm with different number of apertures (n _holes) differing diameter (d) and the spray angle (β).

Below are examples of calculating the spray angle depending on the number of holes in the section and their diameter (figure 4):

Securing the screen sections is possible using the slide rails. For example, with the tunnel working width B = 500 mm, the guide rails are rigidly fixed along the inner wall of the insulated casing 1 at an angle of 2-3 degrees.

With a working width of the chamber B = 700 mm, it is necessary to use additional metal strip sections placed between the wall of the housing 1 and the guide rails on both sides of the tunnel.

Thus, the use of standard screen sections for various modifications of the apparatus is ensured, as well as the possibility of dividing low-temperature air in the chamber by replacing sections of the screen that provide the necessary characteristics of the working environment.

The device operates as follows. The product to be frozen through the window 12 is placed on the transporting body 2, with the help of the drive part 5 on the transporting body the product is moving. Through the pipe 8 and the expansion channel 9 into the chamber direct low-temperature air, which flows to the product. Air bunches, separated from the main stream, pass through the holes in the screen 10, while they gain some acceleration due to a peculiar throttling effect. After this, the bundles of the air flow, longitudinally flowing around the product, freeze it, and at the same time fulfilling their temperature, are sucked back through the device 11 back into the turbo-refrigerating machine. After the product exits through the discharge window 13 from the chamber of the apparatus, it is subjected to packaging and bookmarking for storage in a refrigerator.

The design of the proposed apparatus is simple to manufacture and less energy-consuming, and the apparatus operates using only low-temperature air in it. This environmentally friendly, simple in design device provides the intensification of the process due to blowing with low-temperature air, and the short processing time eliminates weight loss due to drying, improves presentation and maintains the quality of the product.

Claims (2)

1. A freezing tunnel apparatus containing a thermally insulated body forming a chamber with a transporting body for freezing products, connected to a turbo-refrigerating machine through low-temperature air inlet and outlet channels, as well as a low-temperature air inlet distribution system, characterized in that the low-temperature air inlet distribution system is a removable screen rigidly mounted inside the camera inclined to the transporting body, and the screen in Full of detachable sections with holes, wherein the low-temperature air introduced into the expansion chamber is equipped with a channel for distribution of incoming air. 2. The apparatus according to claim 1, characterized in that it is equipped with guide rails mounted on the inside of the housing for positioning sections of the screen on them.

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