SU1735683A1 - Method of receiving frozen cargoes for prolonged storage in refrigerator with landing stage - Google Patents

Abstract

The invention relates to refrigeration and can be used for loading and unloading operations with frozen goods. The purpose of the invention is to increase the safety of cargo. The method involves moving the cargo from the refrigerator to the chambers of the refrigerator through a cooled corridor installed on the landing stage, the temperature in which is maintained equal to the temperature of the incoming cargo, and the flow of cooled air in the corridor is determined in accordance with the temperature sensor indicators, and all technological operations are carried out corridor temperature of the incoming goods. The method eliminates the dehydration of goods, prevents condensation or sublimation of moisture 2 or to

Description

The invention relates to refrigeration engineering and relates to methods of refrigerating processing of frozen goods, for example, meat, fish, poultry, etc., during loading and unloading operations in distribution, commercial and basic refrigerators.

A closed landing stage installed above the platform and railway tracks is known, in which products are transported during loading and unloading operations without refrigerating them,

The disadvantages of this landing stage are the possibility of heating the products and moisture condensation on their surface during the summer period.

There is a method of acceptance of products for storage in the refrigerator, involving the movement of products from refrigerators through a closed refrigerated

a platform inside which the temperature is maintained throughout the year from 0 to + 2 ° C.

The disadvantages of this method are the possibility of heating frozen food, which maintenance of the specified interval does not eliminate, significant energy consumption for maintaining it throughout the year.

The closest in technical essence. The proposed method is a method for transporting frozen food through a corridor connecting a refrigerator and a refrigerator compartment.

The disadvantages of this method include the violation of the main requirement of the refrigerated technology of frozen products - the preservation of a continuous cold chain from the production site of the XI

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to the point of their implementation, i.e. the movement of products under conditions of a stable temperature level, as a result of which frozen products are heated during loading and unloading operations, and during subsequent cooling treatment in the chambers of the refrigerator, losses from shrinkage increase and it is difficult to preserve the quality of products reliably.

This goal is achieved by the fact that in the method of accepting frozen goods for long-term storage in a refrigerator with a landing stage that involves moving them from the refrigerator to the refrigerator’s chambers through the cooled corridor installed in the bar, the air temperature in the corridor is maintained equal to the temperature of the incoming cargo by feeding into the corridor of cooled air from the chambers of the cooler, the flow rate of which is determined by the temperature sensor in the corridor, and all (technological and cargo operations It is dissolved in the latter at this temperature.

When accepting frozen goods, the last significant time has been on the platform of the refrigerator due to technological and cargo operations. During this period, moisture condenses on the surface of frozen goods, as a result of which favorable conditions are created for the development of microflora. At the same time, the loads are heated further, when they are frozen to storage temperature, the losses from shrinkage increase. In addition, a cyclical change in the temperature of the goods, especially such as meat (frozen, warming, freezing), has a negative effect on its quality. As a result of repeated freezing of the heated product, the number of large crystals increases, which degrades the structure of the muscle tissue. The crystals destroy the cells, which leads to the subsequent loss of the meat juice during thawing. At the same time, during storage, the intensity of oxidative processes increases, leading to deterioration of product quality.

When the temperature in the cooled corridor is maintained at a temperature that corresponds to the temperature of the incoming cargo, the listed drawbacks are eliminated; in addition, the warm outside air is not able to penetrate inside the building of the refrigerator, which also prevents the formation of condensate on the surface of walls and ceilings. or not, moreover, there is no need

special facilities for inspection, sorting and other operations with incoming frozen goods.

Supplying the cooled air from the chambers of the refrigerator to the corridor to maintain an appropriate temperature in the corridor makes it possible to use the refrigeration unit operating on the refrigerator, while the thermal load on the cooling devices corresponds to the load that would have occurred during the blast of the chambers. In addition, this cold-storage of the refrigerated corridor reduces operating costs and capital costs by using existing refrigeration equipment.

Regulation of the supply of cooled air by a signal from a temperature sensor in the corridor allows you to reliably and effectively maintain the desired temperature. At the same time, such a control system can be coupled with the automation system of the operation of the existing refrigeration unit.

FIG. 1 is a schematic diagram explaining the implementation of a method for accepting frozen goods for long-term storage in a refrigerator with a demarcher; figure 2 - section a - a in fig, 1.

The method is carried out as follows.

After filing the refrigerator 1 for unloading in the landing stage 2 set the cooled corridor 3 (figure 1). The temperature of the incoming load 4 (Fig. 2) is measured and on the thermal switch 5, the sensor 6 of which is placed in the corridor 3, set the setpoint to the appropriate value. Then the air cooler 7 is put into operation and the cooled air is supplied to the corridor 3 through the air duct 8 and the air intake through the duct 9. When the cooled corridor 3 reaches a temperature corresponding to the temperature of the incoming frozen cargo 4, the latter is transported through the cooled corridor 3 to the chambers of the refrigerator 10. a and its consumption in the air cooler 7 is adjusted via the temperature sensor 6 and the switch 5, the control signal from which is supplied to the damper rotation mechanism 11 and the drive of the fan 12.

PRI me R 1. The implementation of the method is carried out on a basic refrigerator with a capacity of 10 thousand tons, which has a landing stage 2. After supplying an autonomous refrigerator car 1 for unloading, a refrigerated corridor 3, made of thermally insulated pallets, is installed in unloading device 2. The temperature of the incoming cargo (frozen beef) is -6 ° C. On thermostat 5 set the dial 6 to the value of -6 ° C. The air ducts 8 and 9 are connected to supply and take air into the corridor 3 and the air cooler installed in the chamber of the refrigerator 10. The air cooler 7 is activated and the cooled air is supplied to the corridor 3. When the temperature reaches 6 ° C in the last one from the refrigerated wagon 1 to the chambers of the refrigerator 10. Merchandising operations of incoming goods are carried out in a cooled corridor 3.

As the temperature in the cooled corridor rises (lowers) above (below) -6 ° C, temperature control 5 sends a control signal to the flap mechanism 11 to open (close) it and to electrically actuate the valve 12 to open (close) it.

In the storage chambers (for freezing), the cargo arrives with a temperature of -6 ° C at an air temperature in the chambers of -25 ° C.

EXAMPLE 2 The method is carried out analogously to example 1, wherein the temperature of frozen beef is taken as -10 ° C, whereby the temperature is kept at -10 ° C in the cooled corridor, which allows product also with a temperature of -10 ° C.

EXAMPLE 3. The method is carried out analogously to example 1, the temperature of the incoming beef meat (steak) being -12 ° C. The same temperature is maintained in the cooled corridor. The product enters the storage chambers with a temperature of -12 ° C.

Considering the processes of heat exchange between meat and ambient air simultaneously with the processes of internal heat and mass transfer, the product notes the following differences in the flow of these presses in the proposed method and in the known methods.

According to the proposed method, the mass transfer process from the surface of the ms to the ambient air is minimal and depends

only from the difference in partial pressures of air and water vapor above the surface, which is 0.05 Pa when equalizing temperatures, and by known methods

the process of mass transfer is more complex, the processes of condensation and sublimation proceed, and the temperature of the product rises the more intense the higher the temperature of the surrounding air.

During subsequent freezing and storage according to the proposed method, the best results are achieved in examples 1 to 3, since in this case the surface layer of meat dehydrates slightly and the size

coarse crystals (more than 50 µm) do not exceed 30%; this determines higher organoleptic quality parameters of meat.

According to known methods, due to intensive mass exchange of the surface layer of m with ambient air during warming and subsequent freezing, it is significantly dehydrated and the number of large crystals increases to 70%, which degrades quality indicators due to intensive oxidation processes in dehydrated pores filled with air, and cell destruction by large ice crystals followed by

Claims (1)

loss of juice and reduction of water binding capacity by 15–20%. The invention of the method of acceptance of frozen goods for long-term storage in the refrigerator with a landing stage, providing for their movement from the refrigerator to the chambers of the refrigerator through a cooled corridor installed in the landing stage, characterized in that, in order to increase the safety of the cargo, the air temperature in the corridor is maintained equal to the temperature of the cargo received by supplying the cooled air from the chambers of the refrigerator, the flow rate of which is determined in accordance with the indicators of the temperature sensor in the corridor, and all technological and cargo operations are carried out at the latter at this temperature. 2;