JPS6363833B2 - - Google Patents

Description

[Detailed description of the invention] A liquefied solvent with a low boiling point is injected into the low-pressure evaporation tube of the evaporator through an expansion valve and evaporated, and at this time, a large amount of evaporation heat is taken from the circulating cold air to cool it. In air curtain type refrigerated cases, etc., which use a cooling device that uses a compressor to compress the air to high pressure, cool it in a condenser, liquefy it again, and circulate it, a small amount of outside air is always allowed to flow into the air curtain. The moisture in the air gradually forms frost on the evaporator during use, reducing its cooling capacity.
This frost must be removed by some means.

In such refrigerated cases, etc., conventionally,
Normally, an electric heater is installed upwind of the evaporator's air path, and the circulation of the refrigerant is periodically interrupted, and the heater warms the circulating cold air to melt and remove frost.

Therefore, during the defrosting period, the heat from the heater and
Due to the interruption of cooling, the temperature inside the case rises rapidly, which deteriorates the quality of stored food.Also, electricity is required for defrosting, and after defrosting is completed,
The disadvantage is that in order to lower the temperature of the food and the inside of the case, which has once risen, to a predetermined temperature, a larger amount of electric power is required than during normal cold storage operation.

In the present invention, two evaporators are provided in the case, and these are used alternately for cooling, and the frosted evaporator is defrosted by the latent heat of vaporization of the high-temperature refrigerant gas discharged from the compressor. The refrigerant gas is liquefied, and after defrosting, the refrigerant gas is passed through the condenser as in a normal cooling cycle, and the evaporator used for cooling is always supplied with completely liquefied refrigerant. By not interrupting the cooling inside the case even during defrosting, the above-mentioned drawbacks are eliminated, and the heat of the refrigerant allows water eluted from the evaporator during defrosting to reach the low temperature of the cooling device. This article relates to a cooling method and device that prevents the water from freezing when passing through the case and allows the water to be smoothly discharged out of the case.The following is a detailed explanation based on the attached drawings. do.

FIG. 1 shows an air curtain type frozen food display case using the device of the present invention, in which 1 is an outer box with an insulating structure and an opening on the top, 2 is a display box with an opening on the top provided inside the outer box, 3a and 3b are partition plates provided at the front and rear parts between the outer box 1 and the display box 2, respectively; 4a and 4b are partition plates provided between the display box 2 and the front partition plate 3a, and between the rear partition plate 3b, respectively. Circulating cold air passages 5a and 5b formed in the above are bypass air passages 6a and 6 formed between the outer box 1 and the front partition plate 3a and between the rear partition plate 3b, respectively.
7a and 7b are air-flow switching shutters provided at the upper ends of the partition plates 4a and 4b, respectively; 7a and 7b are suction ports facing each other at the upper ends of the cold air air paths 4a and 4b, respectively; 8 is an air curtain; and 9 is a cold air switch. A blower capable of forward and reverse rotation for circulation; 10 is a compressor installed at the rear of the bottom of the outer box 1; 11 is a condenser installed at the rear of the outer box 1; 12a and 12b are cold air channels 4a, respectively. , 4b, 13a and 13b are drainage devices for both evaporators 12a and 12b, and 14a and 14b are drainage devices, respectively. Device 1
The meandering refrigerant pipes 15a and 15b for supplying heat to the drain device 1
A heat insulating material 3a and 13b prevents overcooling, and 16 is a drain pipe.

The front evaporator 12a, as shown in FIG.
It is formed by connecting an evaporator tube 17a bent in a meandering manner and a defrost tube 18a bent parallel to the evaporator tube 18a with a large number of fins 19a. and defrost pipe 18b
and a large number of fins (not shown), and temperature sensors 20a and 20b are installed at key points of both evaporators 12a and 12b, respectively.

FIG. 3 and FIG. 4 are piping diagrams showing the configuration of the apparatus of the present invention, and the thick lines in the figures indicate the path through which the refrigerant passes.

High pressure gas pipe 2 connected to the discharge port of the compressor 10
1 is connected to the inlet of the condenser 11 via the solenoid valve 22a, and is connected to the outlet of the condenser 11 by the bypass pipe 23 via the solenoid valve 22a,
The outlet of the condenser 11 has branch pipes 24a and 24b, and passes through refrigerant pipes 14a and 14b of the front and rear drainage devices 13a and 13b, respectively, to the front and rear evaporators 12.
It is connected to defrosting pipes 18a and 18b of a and 12b.

The outlet of the front defrost pipe 18a is connected to the inlet of the evaporator pipe 17b of the rear evaporator 12b by a communication pipe 25a via a solenoid valve 26a and an expansion valve 27a, and the outlet of the rear defrost pipe 18b is , connecting pipe 25b
Through the solenoid valve 26b and the expansion valve 27b,
It is connected to the inlet of the evaporation pipe 17a of the front evaporator 12b.

The outlets of both evaporation pipes 17a, 17b are connected to the suction port of the compressor 10 through a low pressure gas pipe 28.

1 and 3 show a state in which the front evaporator 12a is defrosting and the rear evaporator 12b is cooling, the solenoid valves 22b and 26a are open, and the solenoid valve 2
2a and 26b are closed, and cold air circulates as shown by the arrows.

At this time, the refrigerant is transferred to the compressor 10→
Front refrigerant pipe 14a → front defrost pipe 18a → solenoid valve 2
6a→expansion valve 27a→rear evaporation pipe 17b→compressor 10, and the refrigerant gas that has been compressed in the compressor 10 and becomes high temperature and high pressure is directly passed through the refrigerant pipe 1.
4a to warm the drainage device 13a and prevent the water eluted from the front evaporator 12a from freezing. Thereafter, while passing through the front defrosting pipe 18a, this refrigerant gas dissolves and removes the frost on the front evaporator 12a, and is itself cooled and liquefied.

Then, it passes through the solenoid valve 26a and expands into the expansion valve 27a.
The circulating air is injected into the evaporator pipe 17b of the evaporator 12b located further back and vaporized, and after taking away a large amount of vaporization heat from the surroundings and cooling the circulating air passing through the evaporator 12b, it is returned to the compressor 10, and as described above. circulates.

This cold air flows from the rear suction port 7b to the front suction port 7a through the cold air path 4b, forming an air curtain 8, and the circulating air whose temperature has increased due to mixing with outside air is transferred to the bypass air. It circulates through the passage 5a and returns to the evaporator 12b to cool the inside of the case.

When the defrosting of the front evaporator 12a progresses and the temperature rises to, for example, +5°C, the temperature sensor 20a detects this and as shown in FIG.
The solenoid valve 22a automatically opens and the solenoid valve 22
b is closed, and the high-temperature, transformed refrigerant gas passes through the condenser 11, liquefies heat with heat dissipation as in a normal cooling device, passes through the front defrosting pipe 18a, completes defrosting, and returns to the compressor 10 as described above. Return to

After defrosting is completed, the blower 9 is reversed and both shutters 6a, 6b are rotated 90 degrees to switch the wind direction and air path, and the solenoid valves 22b, 26b are opened and the solenoid valves 22a, 26a are closed. As described above, the rear evaporator 12b that has been frosted during the above operation is defrosted, and the front evaporator 12a, which has been completely defrosted, cools the circulating air.

In addition, switching the rotation direction of the blower 9, rotating both shutters 6a, 6b by 90 degrees, and solenoid valves 26a,
The opening and closing of the shutters 26b can be easily and automatically synchronized using a timer or the like, and a sliding type can be used instead of the rotary shutters 6a and 6b.

As mentioned above, in the present invention, while one evaporator is defrosting, the other evaporator performs the cooling action, and unlike in a general refrigeration case, there is no interruption of the cooling action during defrosting. The inside of the case can be kept at a low temperature, and the quality of the food inside the case is maintained extremely well.

In addition, for defrosting and preventing freezing of wastewater, we do not use electric heaters, etc., and instead use the refrigerant's alternative heat and sensible heat to lower the liquefied refrigerant to a lower temperature, which improves the cooling effect. , power consumption is lower than conventional devices.

In addition, according to this device, since the defrosting can be carried out frequently, the amount of frost formation is small. Therefore, even if the pitch of the fins 19a is narrowed, the circulation of cold air is not obstructed by frost formation, and therefore evaporation is prevented. The evaporators 12a and 12b can be made smaller, and even if there are two evaporators in the case, the dedicated volume of the evaporators does not increase compared to conventional devices.

[Brief explanation of drawings]

FIG. 1 is a central longitudinal sectional right view of a frozen food display case equipped with the device of the present invention, FIG. 2 is a front view showing an example of an evaporator, and FIGS. 3 and 4 are cooling of the device of the present invention. In the piping diagram of the apparatus, FIG. 3 shows the state of the left evaporator at the initial stage of defrosting, and FIG. 4 similarly shows the state at the end of defrosting. 1...Outer box, 2...Display box, 3...Partition plate, 4...Cold air air path, 5...Bypass air path, 6...Shutter, 7...Suction opening, 8...Air curtain, 9...Blower, 10...
Compressor, 11...Condenser, 12...Evaporator, 13...Drainage device, 14...Refrigerant pipe, 15...Insulating material, 16...Drainage pipe, 17...Evaporation pipe, 18...Defrosting pipe, 19...Fin, 20... Temperature sensor, 21...High pressure gas pipe, 2
2... Solenoid valve, 23... Bypass pipe, 24... Branch pipe,
25...Communication pipe, 26...Solenoid valve, 27...Expansion valve, 2
8...Low pressure gas pipe.

Claims (1)

[Claims] 1. A liquefied refrigerant with a low boiling point is injected from an expansion valve into a low-pressure evaporation pipe of an evaporator and evaporated, and at this time, the heat of evaporation is taken from the circulating cold air passing through the evaporator to cool it. In an air curtain type refrigerating case, etc., in which the vaporized refrigerant is compressed to high pressure using a compressor, then cooled and liquefied in a condenser and circulated, there are two evaporators, and one evaporator While cooling the inside of the case with
Both evaporators are switched and used alternately so that most of the defrost is carried out using the high-temperature refrigerant gas compressed by the compressor, and then the liquefied refrigerant passes through the condenser and is completely defrosted. A cooling method for an air curtain type refrigerated case, etc., characterized by the following. 2. A liquefied refrigerant with a low boiling point is injected into the low-pressure evaporation pipe of the evaporator through an expansion valve and evaporated. At that time, the heat of evaporation is taken from the circulating cold air passing through the evaporator to cool it, and the evaporated refrigerant is In air curtain type refrigerated cases, etc., in which the air is compressed to high pressure using a compressor, then cooled and liquefied in a condenser and circulated, two evaporators are used, and one evaporator is used to internally cool the inside of the case. During cooling, the other frosted evaporator
Both evaporators are switched and used alternately so that most of the defrost is carried out using the high-temperature refrigerant gas compressed by the compressor, and then the liquefied refrigerant that passes through the condenser is completely defrosted. , and a method for cooling an air curtain type refrigerated case, etc., characterized in that a drainage device of the case is heated by the heat of the liquefied refrigerant. 3 A liquefied refrigerant with a low boiling point is injected into the low-pressure evaporation tube of the evaporator through the expansion valve and evaporated. At this time, the heat of evaporation is taken from the circulating cold air passing through the evaporator to cool it, and the refrigerant is vaporized. In air curtain type refrigerated cases, etc., in which the liquid is compressed to high pressure using a compressor, then cooled and liquefied in a condenser and circulated, a partition is installed between the outer case of the case and the display box inside. A plate is used to divide the cold air path and a bypass air path, and a blower that can rotate forward and backward is installed between the partition plates to divide both air paths into two parts, the front cold air path and the rear bypass air path. A cold air circulation system equipped with an air passage switching device that simultaneously blocks the front bypass air passage and the rear cold air air passage, and a bypass pipe that can switch refrigerant passages using a solenoid valve are installed side by side. Defrost pipes are installed in parallel to the condenser and both evaporation pipes arranged in the front and rear cold air channels through fins, and the inlet of each defrost pipe is connected to the outlet of the condenser, and the same The outlet is connected to the inlet of the other evaporation pipe via a solenoid valve and an expansion valve, and the outlet of both evaporation pipes is connected to the suction port of the compressor, and by switching the opening and closing of both the solenoid valves,
The refrigerant passes through both evaporation pipes alternately, and there is a pair of evaporators equipped with temperature sensors at key points.In the early stages of defrosting, the refrigerant passes through the bypass pipe and is sent to the evaporator during defrosting. It consists of an automatic switching device that switches the refrigerant to pass through the condenser when the temperature detected by the installed temperature sensor rises above a predetermined temperature. A cooling device for an air curtain type refrigerated case, etc., characterized by switching the air path and switching the solenoid valves of both evaporators. 4 A liquefied refrigerant with a low boiling point is injected into the low-pressure evaporation tube of the evaporator through the expansion valve and evaporated. At this time, the heat of evaporation is taken from the circulating cold air passing through the evaporator to cool it, and the refrigerant is vaporized. In air curtain type refrigerated cases, etc., in which the liquid is compressed to high pressure using a compressor, then cooled and liquefied in a condenser and circulated, a partition is installed between the outer case of the case and the display box inside. A plate is used to divide the cold air path and a bypass air path, and a blower that can rotate forward and backward is installed between the partition plates to divide both air paths into two parts, the front cold air path and the rear bypass air path. A cold air circulation system equipped with an air passage switching device that simultaneously blocks the front bypass air passage and the rear cold air air passage, and a bypass pipe that can switch refrigerant passages using a solenoid valve are installed side by side. Defrost pipes are installed in parallel with the condenser and both evaporation pipes arranged in the front and rear cold air channels through fins, and the inlet of each defrost pipe is connected to the outlet of the condenser, and the same The outlet is connected to the inlet of the other evaporation pipe via a solenoid valve and an expansion valve, and the outlet of both evaporation pipes is connected to the suction port of the compressor, and by switching the opening and closing of both the solenoid valves,
The front part of the bottom plate of the display box is equipped with a pair of evaporators with temperature sensors installed at key points so that the refrigerant passes through both evaporation pipes alternately, and a refrigerant pipe whose inlet is connected to the outlet of the condenser. A pair of drainage devices installed at the rear and both evaporation pipes installed in the front and rear cold air channels are connected to defrost pipes through fins, and the inlet of each defrost pipe is connected to the drainage device. In addition to connecting to each refrigerant pipe, the outlet is also connected to the inlet of the other evaporator pipe via a solenoid valve and an expansion valve, and the outlet of both evaporator pipes is connected to the suction port of the compressor, and both solenoid valves are connected. By opening and closing the switch, the refrigerant passes through both evaporation pipes alternately.A pair of evaporators are equipped with temperature sensors at key points.At the beginning of defrosting, the refrigerant passes through the bypass pipe, It consists of an automatic switching device that switches the refrigerant to pass through the condenser when the temperature detected by the temperature sensor attached to the evaporator inside rises above a predetermined temperature.After defrosting is completed, the blower is reversed. A cooling device for an air curtain type refrigerator case, etc., characterized in that the air path of the cold air circulation device is switched, and the solenoid valves of both evaporators are also switched.