JPH0311285A - Low temperature warehouse - Google Patents

Abstract

PURPOSE:To smoothly defrost by arranging a refrigerant tube for supplying refrigerant to an evaporator along the downstream side direction of a ventilation passage, and arranging a heater in the tube at the side of introducing of the refrigerant of the evaporator disposed at the downstream side of the air. CONSTITUTION:Since a ventilation passage 10 is reduced in thickness at a branch plate 17 in a low temperature warehouse, refrigerant tubes 30, 31 are affected from each other through the plate 17. When an upper evaporator 18 is being cooled and a lower evaporator 19 is being defrosted, the influence of the tubes 30, 31 arranged at the evaporator 18 affects the tubes 30, 32 of the evaporator 19 to cool it. As a result, the defrost of the tubes 30, 31 of the evaporator 19 is not completely finished. Then, a heater 33 is formed at the branch 31 of the evaporator 19, the heater 33 is energized only at the time of defrosting the evaporator 19, and controlled in synchronization with the energization control of a heater 29 at the downstream side of an electric circuit. Thus, the defrost is smoothly conducted, thereby preventing cooling malfunction from occurring due to an increase in a period of defrosting time.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a cold storage equipped with a plurality of evaporators.

(b) Prior art As a technique Hj preceding the present invention, Japanese Patent Publication No. 60-12542
There is a refrigerated showcase described in the publication.

A refrigerated showcase consists of an insulated box that forms a storage chamber for storing food at low temperatures, a ventilation path formed on the back wall of the insulated box, a blower installed in the ventilation path, and a The refrigerant pipes are provided along the ventilation path to supply refrigerant to the evaporators. As a result, when the l-side evaporator is in cooling operation and the lower evaporator is in defrosting operation, the refrigerant pipe to the upper evaporator is located near the refrigerant pipe that flows into and out of the lower evaporator (the upper evaporator The temperature-affected distance from the refrigerant pipe to the refrigerant pipe*).

Therefore, the temperature of the refrigerant pipe portions flowing into, outflowing from, and protruding from the lower evaporator does not rise, and the defrosting of the lower evaporator ends without being completely defrosted. If defrosting is not performed completely, ice will grow on the portions of the refrigerant pipes that flow into, out of, and protrude from the lower evaporator each time the defrost is performed.

As a result, ventilation resistance due to the evaporator increases, and cooling efficiency and defrosting efficiency deteriorate.

(c) Problems to be Solved by the Invention The technical object of the present invention is to provide a low-temperature refrigerator in which the evaporator can be completely defrosted.

(d) Means for Solving the Problems The present invention provides an insulating box forming a storage chamber for storing stored items at low temperatures, a ventilation passage formed on the inner wall of the insulation box, and a ventilation passage provided in the ventilation passage. It includes an air blower and a plurality of evaporators arranged before and after the air blowing direction in the ventilation passage, and a refrigerant pipe that supplies refrigerant to the evaporators is arranged along the lee direction of the ventilation passage, and a plurality of evaporators are arranged on the leeward side of the ventilation passage. This problem is solved by providing a heater in the refrigerant inflow side refrigerant pipe of the evaporator located in the evaporator.

The present invention also provides a heat insulating box forming a storage chamber for storing stored items at a low temperature, a ventilation passage formed on an inner wall of the heat insulation box, a blower device disposed in the ventilation passage, and a heat insulating box forming a storage chamber in which stored items are stored at low temperature. A refrigerant that is equipped with a plurality of evaporators located at the front and back of the air blowing direction, the ventilation path is branched by a flow divider plate, an evaporator is installed in each of the branched ventilation paths, and refrigerant is supplied to the evaporator. This problem is solved by arranging the pipes along the leeward direction of the ventilation path and arranging the heater in the refrigerant pipe on the refrigerant inflow side of the evaporator located on the leeward side.

The present invention can be implemented by appropriately changing the structure of the grooves within the well-known technical scope of the structure of the above-mentioned means.

In addition, the present invention also applies to the low-temperature storage to which it is implemented.
In addition to oven showcases that are open on the entire surface used in supermarkets, reach-in showcases with doors, prefabricated refrigerators formed by connecting heating plates, etc. can be implemented, and even in temperature bodies, Can be used in various temperature ranges such as refrigerated and frozen.

(B) Effect The present invention is characterized in that the refrigerant pipes that supply refrigerant to the evaporator are arranged along the leeward direction of the ventilation passage, and the heater is arranged in the refrigerant pipe on the refrigerant inflow side of the evaporator located on the leeward side. This makes it possible to heat the refrigerant inflow side refrigerant pipe and block the influence of the refrigerant pipe connected to the upwind evaporator.

In addition, the ventilation path is branched with a flow divider plate, an evaporator is installed in each of the branched ventilation paths, and a refrigerant pipe that supplies refrigerant to the evaporator is placed along the leeward direction of the ventilation path. By installing a heater in the refrigerant pipe on the refrigerant inlet side of the evaporator,
The heat from the heater can block the influence of the refrigerant pipes installed in the narrowed ventilation path.

(f) Example The structure of the present invention will be specifically explained based on an open showcase 1 as a low-temperature refrigerator.

FIG. 2 is a longitudinal left side view of the oven showcase 1. The open showcase 1 has a heat insulating box body 5 consisting of an outer box 2, an inner box 3, and a heat insulator 4 filled with foam between the outer box 2 and the inner box 3. It is equipped with The entire surface of the heat insulating box 5 is open, and the inside of the heat insulating box 5 serves as a storage chamber 6 for storing foodstuffs.

Inside the heat insulating box 5, a first partition plate 7 and a second partition plate 8 are arranged with a gap between them to form a first ventilation path 9 and a second ventilation path 10. The first and second air outlets 11.12 of the first ventilation passage 9 and the second ventilation passage 10 are formed at the opening upper part of the heat insulating box 5, and the first and second suction ports 13.14 are
The first and second air outlets 1 are formed at the lower part of the opening of the heat insulating box 5.
1.12 and the first and second suction ports 13.14 are formed to face each other. A first blower 15 and a second blower 16 are disposed at the lower portions of the first ventilation path 9 and the second ventilation path 10. The air sucked in from the first and second suction ports 13.14 when the first blower 15 and the second blower 16 are operated is as follows:
It flows through the first ventilation passage 9 and the second ventilation passage 10 and is then passed from the first and second air outlets 11 and 12 to the second and second suction ports 13 and 14.
It is blown out towards. - and second outlet 11.12
An air curtain is formed in the entire opening of the heat insulating box 5 by blowing from the air, and the storage chamber 6 is partitioned from the outside of the storage chamber 6.

A flow dividing plate 17 is formed at the back of the second ventilation path 10 to partition the second ventilation path 10 into front and rear sections. An upper evaporator 18 is attached to the upper rear portion of the second ventilation path 10 divided by the flow divider plate 17, and a lower evaporator 19 is attached to the lower portion of the front portion. Refrigerant compressor 20 and condenser 21 forming a refrigeration cycle
The liquid receiver 22, the gas-liquid separator 23, and the like are installed under the outside of the insulation box 5. The refrigeration cycle is formed as shown in FIG. 3, and electromagnetic valves 24, 25 and expansion valves 26, 27 are formed on the refrigerant inflow sides of the upper evaporator 18 and the lower evaporator 19.

The refrigerant supply to each evaporator 618.19 is controlled by opening and closing the solenoid valves 24.25, and the cooling by each evaporator 318.19 is controlled. When operating with the solenoid valves 24 and 25 open, the air from the second blower 16 is cooled by the upper and lower evaporators 18 and 19, and cold air is blown out from the second outlet 12. Even if one of the upper and lower evaporators a1g and x9 is in defrosting operation, the second blower 16 continues to operate mwt.
The temperature of the cold air blown out from the second outlet 12 does not change significantly. Therefore, temperature changes in the storage chamber 6 are also reduced. For defrosting operation, close the solenoid valves 24 and 25 and close the evaporators 18 and 19.
This is done by stopping the supply of refrigerant to the However, the solenoid valves 24 and 25 are not closed at the same time. One solenoid valve (
For example, when 25) is closed, the other 11 is closed.
4) is open, so -L side evaporator 518 is in cooling operation! l! Subsequently, the lower evaporator 519 enters defrosting operation. At this time, the residual liquid refrigerant in the lower evaporator I9 during defrosting can be gradually recovered, and the refrigerant shortage in the refrigeration cycle can be resolved. When the defrosting operation starts, the defrosting electric upper and lower heaters 28 and 29 disposed on the air inflow side of the evaporator that has entered the defrosting operation are energized to supply warm air to the evaporator to defrost. Facilitate. Cooling and defrosting are performed as shown in the operation chart shown in FIG.

The cooling operation of the upper and lower evaporators 18 and 19 is performed for a certain period of time (for example, 2 hours), and then the defrosting operation begins.

The defrosting operation of the upper and lower evaporators 18.19 is delayed alternately, and the defrosting operation is performed when the detected value by the temperature sensor disposed on the air outlet side of the evaporator 18.19 reaches a set value (for example, 5 The process ends when it detects the temperature). 1 is applied to the upper and lower heaters 28 and 29 only during defrosting. When defrosting is completed, water is drained for a certain period of time (for example, 5 minutes), and then cooling operation begins.

Refrigerant pipes that supply refrigerant to each evaporator Ly1g, 19 are arranged downward along the second ventilation path 10. High-pressure liquid refrigerant flows through the refrigerant pipe connected from the condenser 21 to the expansion valve 26.27 via the electromagnetic valve 24.25, and after passing through the expansion valve 26.27, the low-pressure liquid refrigerant flows into the refrigerant pipe 30. Each evaporator 1
Low pressure liquid refrigerant flows into 8.19. The temperature of the low-pressure liquid refrigerant is about -15 degrees. The refrigerant pipes 30 each evaporate 6xs, x9
is forked before entering. Therefore, in the branch part 31, secondary expansion occurs due to the branching of the low-pressure liquid refrigerant, and the temperature of the branch part 31 decreases. As a result, more frost forms on this branch part 31 than on the other parts. For example, refrigerant pipe 30
A four-branch pipe is used, and a five-branch pipe is used for each branched refrigerant pipe. The refrigerant that has passed through each evaporator 18]9 becomes a low-pressure gas refrigerant.

The low-pressure gas refrigerant flows out from each evaporator 18 , 19 through two refrigerant pipes, joins together, and is piped to the gas-liquid separator 23 through a refrigerant pipe 32 . The temperature of the low pressure gas refrigerant flowing through the refrigerant pipe 32 is -
It is 10 to -5 degrees.

Evaporators 18 and 19 are installed at intervals, and refrigerant pipes 30
．． 32 can be piped with such a spacing that they do not exchange heat with each other, the problems described in the prior art will not occur. However, in the oven showcase (low-temperature storage) targeted by the present invention, the refrigerant pipes 30 and 32 have the second ventilation path 10 narrowed at the flow divider plate 17.
They influence each other through the flow divider plates 17. In that case, the upper evaporator 18 is cooling and the lower evaporator 1
9 is being defrosted, the influence of the refrigerant pipes 30.
No. 32 piping section will be affected and cooled. As a result, defrosting of the refrigerant pipes 30, 32 of the lower evaporator 19 is not completely completed. Especially the lower evaporator 19
Defrosting of the branch portion 31 in the refrigerant pipe 30 will not be completed completely.

Therefore, in the present invention, a heater 33 is formed in the branch portion 31 of the lower evaporator 19. The heater 33 is energized only when the lower evaporator 19 is defrosted, and the electric lower heater 29
It is controlled in synchronization with the energization control. Therefore, the heater 33
This prevents the influence of the refrigerant pipes 30 and 32 connected to the upper evaporator 18, thereby allowing complete defrosting.

Note that the present invention is not limited to the above-mentioned structure, and can be implemented by appropriately changing the structure within the well-known technical scope as long as it has the structure specified in the claims as well as the effects. It is something. For example, to defrost an evaporator, instead of using an electric heater, you can simply stop the refrigerant supply to the evaporator and blow air, or you can switch the refrigerant pipes in the refrigeration cycle and use high-temperature, high-pressure gas refrigerant. Hot gas defrosting using an evaporator to defrost the air may also be used.

It can also be used in various ways as a heater 33 disposed in a refrigerant pipe.

(G) Effects of the Invention The present invention eliminates the influence of the refrigerant inflow side refrigerant pipe of the evaporator located on the windward side by disposing a heater in the refrigerant inflow side refrigerant pipe of the evaporator located on the leeward side. Therefore, defrosting can be performed smoothly, defrosting can be completed in about the same time as conventional methods, and there is no cooling failure due to prolonged defrosting time.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show the present invention; FIG. 1 is a cutaway perspective view of essential parts, FIG. 2 is a vertical left side view of an oven showcase as a low-temperature vehicle,
FIG. 3 is a circuit diagram showing a refrigeration cycle, FIG. 4 is an operation chart, FIG. 5 is a perspective view of a branch section without a heater, and FIG. 6 is a perspective view of a branch section equipped with a heater. 1... Oven showcase, 5... Insulated box, 6
... Storage room, 10... Ventilation path, 18°19... Evaporator, 30.32... Refrigerant pipe, 33... Heater.

Claims (1)

[Scope of Claims] 1. A heat insulating box forming a storage chamber for storing stored items at low temperature, a ventilation passage formed on the inner wall of the heat insulation box, a blower device disposed in the ventilation passage, and a ventilation passage. refrigerant pipes are arranged along the leeward direction of the ventilation passage to supply refrigerant to the evaporators. A low-temperature refrigerator with a heater installed in the refrigerant pipe on the refrigerant inflow side. 2. An insulated box forming a storage chamber for storing stored items at low temperatures, a ventilation passage formed on the inner wall of the insulated box, an air blower installed in the ventilation passage, and an air blowing device in the front and back directions of the ventilation inside the ventilation passage. The ventilation passage is equipped with a plurality of evaporators arranged in positions, the ventilation passage is branched by a flow divider plate, an evaporator is arranged in each of the branched ventilation passages, and a refrigerant pipe supplies refrigerant to the evaporator. A low-temperature refrigerator is arranged along the leeward direction of the refrigerator, and a heater is arranged in the refrigerant pipe on the refrigerant inflow side of the evaporator located on the leeward side.