JPH08233438A - Method and device for suitable temperature for connected open showcases during defrosting - Google Patents

Abstract

PURPOSE: To avoid a duplicate installation of evaporator equipment by a method wherein for a large number of showcases, the number of showcases to be defrosted is kept to a small number ratio or higher as a reference, the cooling surface area of an evaporator is made larger than a cooling surface area to hold a suitable temperature of the inside of the showcase by a specified multiple or so, and connected showcases are defrosted in order. CONSTITUTION: For a showcase 1 consisting of 3 units, a ratio for the number of unit to be defrosted is kept 1 unit or higher as a reference, and a codling surface area of an evaporator 20 is made larger than a cooling surface area which is required to hold a specified suitable temperature of the inside of the showcase 1 by the evaporator 20 by approx. 1.3 times. Then, between the showcase 1 of which the cooling is continued, and the showcase 1 under a defrosting, a cool air circulation air circuit of a cold air collecting air passage 2, showcase internal Cold air circulation air passage 5, and circulating air passage 17 for the time of defrosting is detected, and the showcase 1 under a defrosting is held at a specified case internal suitable temperature by the cold air, and all the connected showcases 1 are defrosted in order. By this method, a duplicate installation of the evaporator 20 equipment can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a plurality of freezing and refrigerating open showcases (hereinafter abbreviated as showcases) connected to each other, and when defrosting the evaporators of the showcases, cooling of a plurality of them is continued. Controlling and combining a showcase with one or a few showcases for defrosting,
The showcase during defrosting shares the cooling capacity required for maintaining a predetermined temperature inside the storage compartment with the evaporators of the many showcases that are still cooling, and outputs them on behalf of the shoulders. A cool air circulation air circuit is formed between the case and the showcase being defrosted, and cold air is blown into the showcase being defrosted and circulated so that the showcase being defrosted can be kept at a predetermined temperature suitable for holding. A holding method and device.

[0002]

2. Description of the Related Art Showcases in which a set suitable temperature is kept at about 2 ° C. or less by using one set of one-circuit type evaporator equipment in which one set of evaporators is provided in the showcase and one circuit of a refrigerant control system is used Is widely used.When defrosting this evaporator, the liquid refrigerant supply to the evaporator is stopped to interrupt the cooling process, and then the defrost heat is input to the evaporator from the outside to defrost it. It is carried out.

There is also a showcase in which two sets of evaporators are provided in the showcase and two sets of refrigerant control systems are used, and a two-set two-circuit type evaporator facility is used and the predetermined temperature inside the storage is about 2 ° C. or less. It is used. When defrosting this evaporator, let one set of evaporators continue cooling, interrupt the cooling process of the other set of evaporators, and use hot gas as the defrosting heat source to simultaneously perform defrosting and cooling. Defrosting is carried out by advancing it and replacing it. Further, when a plurality of showcases are connected and used, the showcases provided with the two sets and two circuit type evaporator equipment are connected and used, and when defrosting, the defrosting process similar to the above is performed one by one. It is done.

[0004]

[Problems to be Solved by the Invention] When the products displayed in the showcase are mainly fresh foods, the displayed products may be discolored or their freshness may be deteriorated unless the temperature inside the storage is kept at about 2 ° C or lower. The product value drops significantly. A rise in the internal temperature of about 1 ° C also has an effect. If frost is formed on the evaporator, the cooling capacity will decrease and the temperature inside will rise, so several times a day,
It must be defrosted using a defrosting time of a few minutes to a dozen minutes. When the temperature inside the showcase is kept at about 2 ℃ or lower, complete defrosting must be done by externally inputting an electric heater or hot gas into the evaporator to the defrosting heat source. I can't.

However, in the showcase provided with the above-mentioned set of one-circuit type evaporator equipment, the cooling process of the evaporator is interrupted and the heat for defrosting is inputted, so naturally, during defrosting, a predetermined storage space is provided. It is not possible to maintain the proper temperature for internal retention.

In order to solve this problem, two sets of two-circuit type evaporator facilities are used for improvement, but in a showcase for fresh foods which requires a predetermined optimum holding temperature of -2 ° C. , -2 ° C, two sets of evaporators output 840 kcal / h and 1680 kca, respectively.
Assuming that a showcase required for 1 / h is used, an electric heater is used as a defrost heat source, and 400 W (about 344 kc) is used.
(converted to al / h) is input to the evaporator to defrost,
Sum of 1680 kcal / h and 344 kcal / h 20
If the cooling capacity of 24 kcal / h is not supplied to the showcase during defrosting, it is not possible to maintain the predetermined temperature suitable for keeping inside the storage room at −2 ° C. However, the cooling capacity of the set of evaporators during cooling is 840 kcal / h.

When the defrosting heat is initially input to the evaporator, the input defrosting heat is used as the heat of fusion for frost formation on the evaporator and does not immediately diffuse into the showcase, but diffuses immediately after the completion of defrosting.

Since defrosting time can be shortened by using hot gas as compared with using an electric heater as a defrosting heat source, hot gas is used as a defrosting heat source to perform defrosting for a short time, and Minimize the rise in air temperature and let the two evaporators perform cooling operation just before the temperature of the exhibited product rises, suppressing the rise in the temperature inside the refrigerator and maintaining the predetermined temperature inside the refrigerator. I am trying to get them to do it.

However, even if the defrosting heat is input or the defrosting time is shortened, the showcase during defrosting has a cooling capacity of 1680 k which is necessary to maintain a predetermined temperature suitable for holding in the refrigerator.
Since the supply of the cooling capacity is 840 kcal / h, which is a half of the cal / h, it is difficult to maintain the predetermined suitable temperature for keeping inside the storage room at −2 ° C.

Further, if hot gas is used as a defrosting heat source in order to shorten the defrosting time, a large number of cooling machine parts and multi-branched refrigerant pipes are required, and when a plurality of showcases are connected together. However, since a showcase provided with two sets of two-circuit type evaporator equipment is connected and used, it becomes expensive equipment and requires complicated refrigerant pipes and a refrigerant control device. Therefore, there are many failures, and the effect of suppressing the rise in the internal temperature is great, but if you compare the high cost equipment cost and the difficulty of maintenance management, the effect may be offset, and it is widely used for general use. I haven't arrived.

Therefore, there is a demand for a showcase capable of reliably maintaining a predetermined storage temperature suitable for the showcase during defrosting, particularly for a showcase for fresh food, and the showcase is complicated. It is desired that it does not require a device or complicated control, has few failures, is inexpensive in equipment cost, and can maintain a predetermined temperature suitable for holding in a refrigerator. The present invention has been made in order to meet the above-mentioned demand, and when a plurality of showcases are connected and used, redundant use of the evaporator equipment can be achieved by effectively using the evaporators of the showcases during cooling. Therefore, it is an object of the present invention to provide a method and a device for holding the showcase during defrosting at a predetermined temperature suitable for holding in a refrigerator as a simple device because the equipment cost is low.

[0012]

[Means for Solving the Problems] Connected showcases 1
The cold air collecting air passage 2 shared by A, 1B, 1C and 1D is provided with heat insulation and airtightness, and the showcases 1A, 1B,
1C, 1D are attached at appropriate positions, and cold air suction with a cold air suction fan 6 is provided between the inside cold air circulation air passage 5 of the showcases 1A, 1B, 1C, 1D and the inside of the cold air collecting air passage 2. A wind pipe 7 is provided so as to be electrically connected, and further, a cold air circulating air passage 5 inside the cold air collecting air passage 2 and inside the showcases 1A, 1B, 1C and 1D, and a double wall board 30 on the back side of the display shelf 11. To both sides,
A cold air blowing air pipe 9 with a cold air blowing fan 8 provided with a cold air blowing outlet 10 is provided in a conductive manner, and the showcases 1A, 1
Showcases 1A, 1BB, 1 show a part of the inner cold air circulation air passage 5 on the suction side of the inner cold air circulation fan 12 provided on the lower inner side of the display section floor plate 16 of B, 1C, 1D.
C and 1D are connected so as to be electrically connected to each other to form a cold air circulating air passage 17 for defrosting, and showcases 1A, 1B,
The intake / exhaust partition plate 13 of 1C and 1D is provided with a circulating air vent 14 with a check valve, and the evaporator 2 of the showcases 1A, 1B, 1C and 1D is provided.
0 is increased about 1.3 times as much as the cooling surface area required for maintaining a predetermined temperature suitable for holding in the refrigerator, and the auxiliary expansion valve 26 is provided side by side with the evaporator 20.

[0013]

When a plurality of connected showcases are defrosted, the evaporators are controlled to be combined with a large number of showcases that continue cooling and one or a few showcases that are defrosted. , The combination ratio is set to 3: 1 or more, and is controlled by, for example, 3: 1 or 4: 1 or 5: 1 or 6: 1 to combine the cooling surface area of the evaporator with a showcase. Is about 1.3 times larger than the cooling surface area required for maintaining a predetermined temperature suitable for holding in the refrigerator. Therefore, if three showcases that continue cooling and one showcase that defrosts are controlled to perform defrosting in combination, three showcases that continue cooling will become one showcase that is defrosting. Maintaining a predetermined inside storage The cooling capacity required to maintain an appropriate temperature is divided by one third and supplied by the operation of the cold air suction fan and the cold air blowing fan. The proper temperature can be maintained reliably. As the combination ratio becomes 4: 1 or 5: 1, the cooling capacity shared by the evaporators per showcase that continues cooling can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With respect to claim 1, the cooling capacity of an evaporator is related to the product of heat transfer rate, cooling surface area and average temperature difference. When the evaporation temperature of the liquid refrigerant in the evaporator is the same, increasing the cooling surface area or improving the heat passage rate increases the cooling capacity.

Increasing the cooling surface area of the evaporator by about 1.3 times the cooling surface area required for the showcase to maintain a predetermined temperature suitable for holding inside the refrigerator during normal cooling operation is as follows.
It is considered to be an allowable range in consideration of securing space to increase and economical efficiency of increasing equipment cost. Therefore, assuming that the showcase being defrosted has a cooling capacity necessary to maintain a predetermined temperature in the storage compartment to be 100, the three showcases that continue cooling increase the cooling surface area by about 0.3 times. The cooling capacity is increased by about one third to output 100, and the showcase during defrosting is kept at a predetermined temperature suitable for holding in the refrigerator. Therefore, the combination of three showcases that continue cooling and one showcase that defrosts is the minimum number of combined showcases, and four or more connected showcases are the same as the ones during defrosting of the present invention. It is the number of connected units that can carry out the appropriate holding temperature method.

Increasing the flow rate of the circulating air passing through the evaporator improves the heat passing efficiency of the evaporator. Therefore, due to the increase in the cooling surface area of the evaporator and the functions of both the cool air suction fan and the cool air blowing fan, the showcase during defrosting to which the defrosting heat has been input has the same temperature as during normal cooling operation. The shared cooling capacity required to maintain the appropriate temperature for holding the inside of the refrigerator is shared, and the showcase during defrosting is reliably kept at the predetermined temperature for holding the inside of the refrigerator.

Referring to claim 2, FIG. 1 is a side elevational sectional view of a wall surface showcase constructed according to the present invention. FIG. 2 is a partially cutaway perspective view in which four wall surface showcases having the structure according to the present invention are connected. The types of showcases are roughly classified into those for wall surfaces and those for flat surfaces, and the structure of the present invention will be described using wall surface showcases with reference to FIGS. 1 and 2.

Furthermore, the minimum number of wall showcases 1 (three showcases for continuing cooling and one showcase for defrosting) (when connected, 1A and 1A, respectively)
B, 1C, and 1D) will be described using a case where four units are connected.

Four showcases 1 are connected to form 1A, 1
B, 1C, 1D, and the common cold air collecting air duct 2 is attached to the upper side of the top plate 3 as an appropriate position of the connected showcases 1A, 1B, 1C, 1D with heat insulation and airtightness. The bottom plate side is suitable as an appropriate position of the flat showcase, and the outside of the back wall of the wall showcase can also be used. The cold air collecting wind passage 2 is attached integrally by being integrally assembled at the showcase installation site or separately manufactured at the factory and connected at the site.

A part of the outside internal circulation air passage 4 of the showcases 1A, 1B, 1C, 1D is penetrated to form a part of the inside internal cold air circulation air passage 5 and the inside of the cool air collective air passage 2. A cold-air suction air duct 7 with a cold-air suction fan 6 is provided for electrical connection. Further, a cold air blowing air pipe 9 with a cold air blowing fan 8 is provided from inside the cold air collecting air passage 2, a cold air blowing outlet 10 is provided inside the internal air circulation air passage 5, and further to the back side of the display shelf 11 with a double wall board 30. Is provided, and the cold air outlet 10 is provided so that both are conducted.

For the convenience of maintenance and inspection, the cold air suction fan 6 and the cold air blowing fan 8 are installed at the respective cold air suction air pipes 7 and cold air blowing air pipes 9 in the cold air collecting air passage 2. Attach. An inspection port 28 is attached to the cold air collecting wind passage 2 at a proper position by attaching a door.

A circulation fan 14 with a check valve is provided on the intake / exhaust partition plate 13 to which the internal cold air circulation fan 12 is fixed. The air curtain suction port 15, the display floor plate 16, and the intake / exhaust partition plate 13 are provided so that a part of the internal cold air circulation air passage 5 is electrically connected between the showcases 1A, 1B, 1C, 1D. By connecting, the recirculation wind passage 17 for defrosting is formed.

FIG. 3 is a side elevational sectional view of the wall surface showcase having the structure according to the present invention, and is an explanatory view showing the circulating air flow in the refrigerator during a normal cooling operation. The single-headed arrow in the figure indicates the flow direction of the circulating air. There is an outside circulation air flow that circulates in the outside inside circulation air passage 4 while forming an outside air curtain between the outside air curtain outlet 19 and the air curtain suction port 15 by the outside inside circulation fan 18. The inside cold air circulation fan 12 passes through the evaporator 20 to form cool air, and circulates in the inside cold air circulation air passage 5 while forming an inside air curtain between the inside air curtain outlet 21 and the air curtain suction port 15. There is a cold air circulating air flow inside the inside of the refrigerator to maintain a predetermined appropriate temperature for holding inside the refrigerator. A part of the cold air is blown out from the inner wall surface of the display shelf 11.

FIG. 4 is an explanatory view showing the circulating air flow in the refrigerator when defrosting the evaporator shown in the side elevational sectional view of the wall surface showcase having the structure according to the present invention. FIG. 5 is a schematic connection front view when four wall surface showcases having the configuration according to the present invention are connected, and is an explanatory view showing a circulating air flow in the refrigerator when defrosting the evaporator 20 of the showcase 1A. Is. The single-headed arrow in the figure indicates the flow direction of the circulating air.

The defrosting of the evaporator 20 of the showcase 1A will be specifically described with reference to FIGS. 4 and 5. When the showcases 1A, 1B, 1C and 1D are wall showcases for fresh foods having a predetermined temperature inside the storage compartment of -2 ° C, 1680 kcal /
The compressor 22 has a refrigerating capacity of 1680 kc.
8736 obtained by multiplying four units of al / h by 130%
A device that outputs kcal / h is selected, an electric heater is used as a defrost heat source, and 800 W (about 688 kcal / h conversion) is output.

Showcases 1A, 1 during normal cooling operation
When 1A of B, 1C and 1D has reached the defrosting time to defrost the evaporator 20, the defrosting heat of the evaporator 20 is 688k.
cal / h is input. In order for the showcase to which the defrosting heat has been input to maintain the predetermined storage temperature within the storage −2 ° C,
The sum of 80kcal / h and 688kcal / h 2368
It is maintained if a cooling capacity of kcal / h is supplied. The cooling capacity that the showcases 1B, 1C, and 1D that continue to cool are equally distributed to supply each is 790 kcal / h, which is 1/3 of 2368 kcal / h. Each of the showcases 1B, 1C, and 1D may output the sum of 1680 kcal / h and 790 kcal / h, 2470 kcal / h, while maintaining the self-holding optimum temperature of −2 ° C. Evaporator 20
Has increased the external cooling surface area by about 1.3 times.
About 2 obtained by multiplying 680 kcal / h by about 130%
184 kcal / h is output. Further, by rotating the cool air suction fan 6 and the cool air blowing fan 8, the showcase 1B,
The amount of circulating air passing through the 1C and 1D evaporators 20 increases, the heat passage rate improves, and the cooling capacity increases. Therefore, both functions act to sufficiently share and supply the cooling capacity of 2470 kcal / h required by the showcase 1A during defrosting, thereby maintaining a predetermined temperature suitable for holding in the refrigerator.

In order to increase the cooling surface area of the evaporator 20, the set of evaporators 20 may be integrally enlarged to increase the size thereof, or the sub-evaporator 23 may be separately provided and increased. Select the one to be used by comparing whether the installation space of the evaporator can be sufficiently secured in the showcase and the economical efficiency.

When the sub-evaporator 23 is used, it can be connected to the evaporator 20 in series or in parallel. The evaporator 20 is used when connected in series as shown in FIG.
The mounting position of the temperature sensitive tube 29 of the main expansion valve 24 of the evaporator 20 is
Of the secondary expansion valve 26 of the secondary evaporator 23.
The mounting position of the temperature sensitive tube 29 is fixed to the final evaporator of the sub-evaporator 23, and the superheat degree when the evaporator 20 and the sub-evaporator 23 are connected in series and integrated is detected.

The orifice of the main expansion valve 24 is the evaporator 20.
A liquid refrigerant that matches the cooling capacity is used, and the orifice of the sub-expansion valve 26 allows the liquid refrigerant that matches the total cooling capacity output by both the evaporator 20 and the sub-evaporator 23 to pass. To use. Even when the evaporator 20 is integrally increased in size to increase the cooling surface area, it is divided into the evaporator 20 and the sub-evaporator 23, and the temperature sensing tube 29 is mounted at the same mounting position as described above, and the orifice is also selected. It will be similar.

When defrosting the evaporator 20 of the showcase 1A, the main solenoid valve 25 of the showcases 1A, 1B, 1C and 1D is closed and the sub solenoid valve 27 of the showcases 1B, 1C and 1D is opened. , Showcase 1A cold air blowing fan 8
And the cold air suction fan 6 of the showcases 1B, 1C, 1D is rotated to energize the electric heater as defrost heat to the evaporator 20 and the sub-evaporator 23 of the showcase 1A. When the sub-evaporator 23 is connected in series, the temperature sensing tube 29 of the main expansion valve 24
Detects the degree of superheat of the evaporator 20, and the inside of the sub-evaporator 23 is filled with the refrigerant vapor to cause less frost, but it is more reliable to input the defrosting heat.

Showcases 1B, 1C, 1 under cooling
There is already a cold air flow circulating in the inner cold air circulation fan 5 by the inner cold air circulation fan 12 of D, and the rotation of the cold air suction fan 6 and the cold air blowing fan 8 of the showcase 1A during defrosting. By rotating both of the above, the inside cold air circulation of the showcase 1A is performed via the cold air suction air duct 7 of the showcases 1B, 1C, 1D, the cold air collecting air duct 2 and the cold air blowing air duct 9 of the showcase 1A. The cold air outlet 10 provided on the double wall plate 30 on the back side of the air duct 5 and the display shelf 11 circulates in the showcase 1A or directly contacts the displayed product to cool it, and the defrosting circulation flow. The air flows through the air passage 17 from the circulating air vent 14 with check valve of the showcases 1B, 1C, 1D, passes through the evaporators 20 and the sub-evaporators 23 in contact with each other, and becomes cold air. Inflow and circulate via the same as above Cooling air flow is formed, the cooling capacity is shared and supplied from the showcases 1B, 1C, 1D that are continuing to cool, and the showcase 1A that is being defrosted is held at a predetermined storage temperature of -2 ° C until the defrosting end time. To do.

When the defrosting of the evaporator 20 and the sub-evaporator 23 of the showcase 1A is completed, the input of the defrosting heat is stopped, and the sub-solenoid valve 27 of the showcases 1B, 1C and 1D which is continuing cooling is closed, Showcase 1 after pump down time
The main solenoid valves 25 of A, 1B, 1C and 1D are opened, and the cold air blowing fan 8 of the showcase 1A and the showcases 1B,
When the cold air suction fan 6 of 1C, 1D is stopped, all the connected showcases 1A, 1B, 1C, 1D return to the normal cooling operation.

The diameters and numbers of the cold air suction air pipes 7 and the cold air blowing air pipes 9 and the air volumes of the cold air suction fan 6 and the cold air blowing fan 8 are selected depending on the number of connected showcases. It may be used so that the intake air volume and the blown air volume circulate in a balanced manner.

The air curtain wind speed of the showcase is said to be 0.8 to 1.2 rice per second at the inner and outer air curtain outlets 19 and 21, and the evaporator 20 is suitable.
And, the heat transfer rate of the sub-evaporator 23 is about 0.
Increasing the amount of about 5 rice can improve the heat transfer rate by about 10%. Therefore, the cold air circulation that can supply the cooling capacity necessary for the showcase during defrosting to maintain a predetermined temperature suitable for holding in the refrigerator without impairing the inside / outside air curtain effect of the showcase itself during cooling is continued. Select and use those that can be performed.

Subsequently or after a lapse of time, the undefrosted showcases 1B, 1C and 1D which are being continuously cooled are sequentially controlled to the same ratio as described above to perform defrosting in combination. The check valve-equipped recirculation air outlet 14 is closed by the wind pressure of the inner cold air circulating fan 12 during the normal cooling operation, and no back flow is performed in the inner cold air circulating air passage 5. Compressor 2 during defrosting operation
The refrigerating capacity of No. 2 is the showcase 1B, 1 which continues cooling.
Since C and 1D merely output the cooling capacity of the showcase 1A during defrosting, the cooling capacity is not insufficient.
Since the selection was made with a margin of refrigeration capacity of about 30%, there is ample margin.

FIG. 6 is a front view showing four wall surface showcases having the structure according to the present invention, which are connected to each other.
On the other hand, it is a refrigerant control explanatory view at the time of defrosting when the sub-evaporators 23 are connected in parallel.

The sub-evaporator 23 is connected in parallel to the evaporator 20 by piping. The mounting position of the temperature sensing cylinder 29 of the main expansion valve 24 of the evaporator 20 is fixed to the final evaporation pipe of the evaporator 20,
The mounting position of the temperature sensing cylinder 29 of the sub expansion valve 26 of the sub evaporator 23 is fixed to the final evaporation pipe of the sub evaporator 23 to detect the degree of superheat. As the orifices of the main expansion valve 24 and the sub expansion valve 26, those that allow the liquid refrigerant to pass through according to the refrigerating capacity of the evaporator 20 and the sub evaporator 23 are used.

When defrosting the evaporator 20 of the showcase 1A, the main solenoid valve 25 of the showcase 1A is closed, the sub solenoid valves 27 of the showcases 1B, 1C, 1D are opened, and the main solenoid valve 25 is Leave the valve open. Showcase 1B,
From the sub-evaporators 23 of 1C and 1D, the cooling capacity required for the showcase 1A during defrosting to maintain a predetermined temperature in the storage compartment of −2 ° C. is shared.

When the defrosting of the evaporator 20 of the showcase 1A is completed, the auxiliary solenoid valve 27 of the showcases 1B, 1C and 1D is used.
And the main solenoid valve 25 of the showcase 1A is opened, all the connected showcases 1A, 1B, 1C, 1
D returns to normal cooling operation.

In order to increase the cooling surface area of the evaporator 20 by about 1.3 times, the evaporator 20 may be integrally enlarged and used, the sub-evaporator 23 may be separately provided, or may be connected in series. It is free to use in parallel connection, and there is no difference in the output of the refrigerating capacity depending on the usage.

[0041]

With the above structure, when a plurality of showcases are connected and used, one set of showcases is provided with two sets of evaporators, and the refrigerant control system is provided with two circuits, so that complicated control can be performed at high equipment cost. Even if a plurality of showcases equipped with an evaporator facility that does not need to be connected are used together, by effectively using all the evaporators of the connected showcases, it is possible to use a plurality of circuit-controlled ones provided with a plurality of sets of evaporators. It can be considered that the showcase of the stand was obtained. Therefore, the number of cooler parts to be used is reduced, the control is simple, and the maintenance management is easy with inexpensive equipment. The showcase during defrosting can surely maintain a predetermined temperature suitable for holding in the refrigerator. Regardless of the length of the defrosting time, the inside of the showcase during defrosting can be maintained at a predetermined appropriate temperature inside the refrigerator, so that it is not necessary to use hot gas for the defrosting heat source. Because an electric heater is used as a defrosting heat source,
The number of cold parts is even smaller, there are few failures, and control is extremely simple.

As a side effect, if cold air is circulated to the showcase in which the cooling function has failed from the showcase in which cooling continues as in the above case, the showcase in failure is stored in a predetermined storage space. It is possible to maintain a suitable holding temperature and suppress deterioration of the quality of exhibited products.

[Brief description of drawings]

FIG. 1 is a side elevational cross-sectional view of a wall surface showcase having a structure according to the present invention.

FIG. 2 is a partially cutaway perspective view of a four-unit connected wall surface showcase configured according to the present invention.

FIG. 3 is an explanatory diagram showing a circulating air flow in the refrigerator during a normal cooling operation of the wall surface showcase having the structure according to the present invention.

FIG. 4 is an explanatory diagram showing a circulating air flow in the refrigerator during defrosting of the evaporator of the wall-mounted showcase having the structure according to the present invention.

FIG. 5 is an explanatory view showing the inside of a four-unit connected wall surface showcase configured according to the present invention, and showing the circulating air flow inside the refrigerator when defrosting the evaporator 20 of the showcase 1A.

FIG. 6 is an explanatory diagram showing the inside of a four-unit wall surface showcase having the configuration according to the present invention, and a refrigerant control diagram during defrosting when the sub-evaporator 23 is connected in parallel to the evaporator 20.

[Explanation of symbols]

 1 Open showcase 1A Open showcase 1B Open showcase 1C Open showcase 1D Open showcase 2 Cold wind collecting wind passage 3 Top plate 4 Outside inside circulation air passage 5 Inside inside circulation air passage 6 Cold air suction fan 7 Cold air suction air Tube 8 Cold air blowing fan 9 Cold air blowing air tube 10 Cold air outlet 11 Display shelf 12 Cooling air circulation fan inside the storage compartment 13 Suction / exhaust partition plate 14 Circulating air vent with check valve 15 Air curtain suction port 16 Display floor plate 17 Circulation flow for defrosting Air passage 18 Outer circulation fan 19 Outer air curtain outlet 20 Evaporator 21 Inner air curtain outlet 22 Compressor 23 Sub-evaporator 24 Main expansion valve 25 Main solenoid valve 26 Sub-expansion valve 27 Sub-solenoid valve 28 Check port 29 Temperature-sensitive tube 30 Double wall board

Claims (2)

[Claims] 1. When a plurality of freezing and refrigerating open showcases are connected and used to defrost the evaporator of the open showcases, a large number of cooling continues and one or a small number of defrosters. Based on the ratio of the number of units to be defrosted to the unit of three units to continue cooling, the combination ratio is controlled to be frosted and controlled, and the cooling surface area of the evaporator is set to be equal to the opening of the evaporator. The showcase is increased by about 1.3 times the cooling surface area required to maintain a predetermined temperature in the refrigerator, and an auxiliary expansion valve is attached to the evaporator.
When the defrosting is continued, the evaporator of the open showcase continues to be cooled by supplying the liquid refrigerant in proportion to the cooling capacity output by the increased cooling surface area to continue cooling and the open showcase during defrosting. Between the two, a cold air circulation air circuit is formed to circulate the cold air, and the open showcase that is being defrosted by the cold air is maintained at a predetermined temperature suitable for holding in the refrigerator,
A method for maintaining an appropriate temperature during defrosting of connected open showcases, characterized in that all of the connected open showcases are controlled and combined in the same manner as described above and defrosted sequentially. 2. A cold air collecting air duct 2 shared by the connected frozen and refrigerated open showcases 1A, 1B, 1C, 1D.
Is attached to the open showcases 1A, 1B, 1C and 1D by providing appropriate heat insulation and airtightness, and the cool air circulating inside the open showcases 1A, 1B, 1C and 1D is circulated. A cold air suction air pipe 7 with a cold air suction fan 6 is provided to connect between the air passage 5 and the inside of the cold air gathering air passage 2, and the inside of the cold air gathering air passage 2 and the open showcases 1A, 1B, 1C. , 1D inside cold air circulation air passage 5
And the cold air blowing air pipe 9 with the cold air blowing fan 8 having the cold air blowing outlets 10 provided on both sides of the double wall plate 30 on the back side of the display shelf 11 so as to be electrically connected, and the open showcases 1A, 1
Part of the inner cold air circulation fan 5 on the suction side of the inner cold air circulation fan 12 provided on the lower inner side of the display section floor plate 16 of B, 1C, 1D is opened to the open showcase 1A,
1B, 1C and 1D are connected so as to be electrically connected to each other to form a defrosting recirculation air passage 17, and the intake / exhaust partition plate 13 of the open showcases 1A, 1B, 1C and 1D is recirculated with a check valve. An open showcase 1A, 1 with a wind vent 14
The B, 1C, and 1D evaporators 20 are increased to about 1.3 times the cooling surface area required when maintaining a predetermined temperature in the storage compartment, and the evaporator 20 is provided with the auxiliary expansion valve 26. A suitable temperature maintaining device during defrosting of the connected open showcase, characterized by.