JPH05778Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a show case having two systems of evaporators that can be operated separately for cooling or defrosting.

(Prior Art) The structure of a conventional show case of this type is shown in FIG. In the figure, reference numeral 1 denotes a case body, and heat insulating panels 10 are arranged on the top, back, bottom, and side surfaces of the main body, forming a top wall 10a, a back wall 10b, a bottom wall 10c, and a side wall 10d, respectively. ing. An inner box 12 is provided inside the refrigerator to form a wind passage 11 along the top wall 10a, back wall 10b, and bottom wall 10c. Furthermore, the upper wall portion 10
The air passages 11 in the bottom wall portion 10c and the bottom wall portion 10c are divided into two layers, upper and lower. Although not shown, the air passage 1
1 is divided into three parts in the direction of the side wall part 10d at the back wall part 10b. Further, an evaporator and a damper, which will be described later, are arranged in the center of the air passage divided into three (for example, Utility Model Publication No. 55-10853).

The front opening of the case body 1 has an air outlet 1.
4. An inlet 15 is provided, and as shown by the dashed line, uncooled air 16a is sent from the outlet 14 to the inlet 1 by a blower (not shown).
5. Air passage 11 below the bottom wall 10c, back wall 1
Air passages provided on both sides of 0b (not shown)
The air is circulated through the air passage 11 on the upper side of the upper wall portion 10a. Inside this uncooled air 16a, air 16b cooled by heat exchange between the evaporators 22 and 23 is transferred to the air outlet 14, the suction port 15, and the bottom of the air by the blower 17, as shown by the solid line. Wall part 10
It circulates through the air passage 11 on the upper side of c, the air passage 13 provided in the center of the back wall part 10b, and the air passage 11 on the lower side of the upper wall part 10a. Thus, the air curtain 16 is formed by these two types of wind. In addition, there is a shelf board inside the refrigerator as shown in the diagram.
8. A screen board 19 is provided to display products.

The air passage 13 provided at the center of the back wall portion 10b described above is divided into two sections in the front-rear direction of the case body 1 by providing the partition plate 20 in parallel between the back wall portion 10b and the inner box 12. It is divided into layers to form a first air passage 20a and a second air passage 20b. This partition plate 20 is bent at the center, and below the center there is a first air passage 20a.
is narrowed, and a second air passage 20 is formed above the center.
A step is formed to narrow b.

Above the first air passage 20a, there is a partition plate 20 and a mounting plate 2 provided on the inner box 12 as shown in the figure.
1, the first evaporator 22 is connected to the refrigerant inlet side 22a.
is placed facing upward and its exit side 22b facing downward,
Fixed. Further, below the second air passage 20b, a second
The evaporator 23 is arranged and fixed with its refrigerant inlet side 23a facing upward and its outlet side 23b facing downward.

Furthermore, a first air passage 20 is provided at the upper end of the partition plate 20.
A damper unit 24 housing a damper 24c for controlling the opening and closing of the first and second air passages 20b and 20b is installed, and above this damper unit 24,
A blower 17 is provided for circulating air as shown by solid arrows in the figure.

Next, a conventional refrigerant circuit will be explained with reference to FIG. An outlet side 25a of the compressor 25 is connected to a condenser 26, and the outlet side of the condenser 26 has three terminals, and each terminal is provided with a solenoid valve 27a, 27b,
27c is connected. Further, the solenoid valve 27a on the left side of the figure is connected to the inlet side 22a of the first evaporator 22, and the solenoid valve 27c on the right side is connected to the inlet side 23a of the second evaporator 23. Solenoid valve 27a, 2
7b and between the solenoid valves 27b and 27c, check valves 28a and 28b facing leftward and rightward, respectively, are provided, and between the solenoid valve 27a and the check valve 28a,
Expansion valves 29a and 29b are provided between the electromagnetic valve 27c and the check valve 28b, respectively. Outlet sides 22b, 23 of the first and second evaporators 22, 23
Solenoid valves 27d and 27e are connected to the inlet side 25b of the compressor 25, respectively. Also, the first and second
The outlet sides 22b, 23b of the evaporators 22, 23 are connected through a pair of mutually opposing check valves 28c, 28d, and a solenoid valve 27b is connected between the check valves 28c, 28d.

Next, the operation mode of this refrigerant circuit will be explained.

First, when the solenoid valves 27b, 27c, and 27d are turned off and the solenoid valves 27a and 27e are turned on, the refrigerant exiting the compressor 25 passes through the condenser 26 and the solenoid valve 27a, and defrosts the evaporator 22. and the evaporator 2 through the check valves 28c, 28b and the expansion valve 29b.
3, and returns to the compressor 25 through the electromagnetic valve 27e. Therefore, the evaporator 22 is defrosted, and the evaporator 23 is in a cooling operation (first mode).

Next, when the solenoid valves 27a, 27b, and 27e are turned off and the solenoid valves 27c and 27d are turned on, the refrigerant leaving the compressor 25 passes through the condenser 26 and the solenoid valve 27c, and reaches the evaporator 23. Then, the evaporator 23 is defrosted, and the check valves 28d and 28a and the expansion valve 29 are
It is cooled by the evaporator 22 through the solenoid valve 27d and returned to the compressor 25. Therefore, the evaporator 22 performs a cooling operation, and the evaporator 23 is defrosted (second mode).

Furthermore, the solenoid valves 27a and 27c are turned off,
If the solenoid valves 27b, 27d, and 27e are turned on,
The refrigerant that has exited the compressor 25 is sent to a condenser 26 and a solenoid valve 27.
b, it is divided into two parts, one is a check valve 28a,
It passes through the expansion valve 29a, undergoes heat exchange (cooling) in the evaporator 22, and returns to the compressor 25 via the electromagnetic valve 27d. The other one passes through the check valve 28b and the expansion valve 29b, undergoes heat exchange (cooling) in the evaporator 23, and returns to the compressor 25 via the electromagnetic valve 27e. Therefore, both evaporators 22 and 23 perform a cooling operation (third mode).

The mode is 1st → 3rd → 2nd → 3rd → 1st →
The process is repeated in the order of 3rd →..., but when moving from the 1st to the 3rd, or from the 2nd to the 3rd, the evaporator 22 or 23 is already full of liquid refrigerant. Just use the solenoid valve 27d or 27
If e is opened, liquid refrigerant may flow into the inlet side 25b of the compressor 25 and breakage may occur. Therefore, when moving from the first mode to the third mode, the solenoid valve 27
a is turned off and only the solenoid valve 27e is left on to vaporize the liquid refrigerant in the evaporator 22 (fourth mode). 27c is turned off and only the solenoid valve 27d is left on, and after the liquid refrigerant in the evaporator 23 is vaporized (fifth mode), the mode is shifted to the third mode.

Next, the damper unit will be explained with reference to FIGS. 3 and 5. The damper unit 24 has a damper shaft 24 in a housing 24a that is open vertically.
b, and the damper 2 is attached to this damper shaft 24b.
4c is installed. and damper 24c
By rotating the damper shaft 24b, the damper can be stopped and fixed at the positions indicated by A, B, and C in FIG. Therefore, when the evaporator 22 is performing a defrosting operation and the evaporator 23 is performing a cooling operation, the damper 24c
That is, the first mode (including the fourth mode)
In the case where the evaporator 22 is held at position A, only the air passage 20b is opened, and the evaporator 22 performs a cooling operation and the evaporator 23 performs a defrosting operation, that is, the second mode (including the fifth mode). ) at position B
When the evaporators 22 and 23 perform a cooling operation, that is, in the third mode, the evaporators 22 and 23 are held at position C and controlled to open both the air passages 20a and 20b. be done. This case is therefore continuously cooled.

(Problem that the invention attempts to solve) By the way, in the case mentioned above, the evaporator 2
The flow of refrigerant in the evaporators 2 and 23 occurs from above the evaporator and flows out from below, resulting in the following problems.

() During defrosting, the temperature of the upper part of the evaporator immediately rises due to the liquid refrigerant flowing in, and the frost is melted, but the lower part is difficult to thaw the frost because the refrigerant that has lost heat in the upper part flows into the evaporator. It takes a lot of time.

() During defrosting, when the frost melts, the temperature of the evaporator rises to the same level as the temperature of the liquid refrigerant, warming the air around the evaporator. However, what actually heats up is the air at the top of the evaporator, where the frost melts quickly, so this warm air does not touch the frost at the bottom of the evaporator, but instead becomes an upward airflow that connects the evaporator and damper unit. The heat of the refrigerant cannot be used effectively.

() Especially when the airtightness or insulation of the damper is poor, the warm air accumulated in the space between the evaporator and the damper unit mentioned above passes through the damper.
This increases the temperature of the air cooled by the other evaporator.

On the other hand, in the case, if the refrigerant is made to flow from the lower part of the evaporators 22 and 23 and flow out from the upper part, the above-mentioned problems (), (),
() is solved, but in this case, unless one evaporator is filled with liquid refrigerant, liquid refrigerant will not be supplied to the other evaporator (cooling side), so a very large amount of refrigerant is required. If the amount is too low, the refrigerant will become defective. In addition, even if the amount of refrigerant is sufficient, it takes time for the evaporator to be filled with liquid refrigerant during defrosting, and during that time, the amount of refrigerant supplied to the evaporator on the cooling side is drastically reduced, resulting in low pressure in the refrigerator. There was a risk that the cut would operate and cause cooling failure.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a show case that shortens the defrosting time, reduces the rise in internal temperature caused by the evaporator during defrosting, and improves cooling efficiency.

(Means for solving the problem) In order to solve the above problem, the present invention includes two systems of evaporators arranged in the air passage inside the case body, and the refrigerant from the condenser is directly transferred to the first evaporator. The refrigerant is sent to the second tank and operated for defrosting, and the refrigerant is passed through the expansion valve to the
In the first mode, the refrigerant from the condenser is sent directly to the second evaporator for cooling operation, and in the second mode, the refrigerant is sent to the first evaporator through the expansion valve for cooling operation. and a third mode in which refrigerant from the condenser is sent to the first and second evaporators for cooling operation through an expansion valve. As the second evaporator, an evaporator is used, which consists of two layers, upper and lower, each having an independent refrigerant inlet and outlet at the upper and lower parts, and in which the volume of the lower layer is smaller than that of the upper layer, and the refrigerant from the condenser is was first fed into the lower layer of the evaporator from the upper inlet to the lower outlet, and then into the upper layer from the upper inlet to the lower outlet.

(Function) According to the above configuration, when defrosting, the lower part of the evaporator is first warmed and defrosted by the liquid refrigerant.
After defrosting, the air warmed by the lower part of the evaporator rises toward the upper part of the evaporator, which promotes defrosting of the upper part of the evaporator and reduces the heat of the liquid refrigerant during defrosting. Effective utilization can be achieved, defrosting time can be shortened, and the air warmed by the lower part of the evaporator loses its heat when heating the upper part of the evaporator, resulting in a lower temperature. Therefore, the temperature of the air above the evaporator during defrosting will not be increased more than necessary, and the temperature of the air cooled by the other evaporator will not be increased, which will affect the internal temperature. Furthermore, since the refrigerant flows from the upper inlet to the lower outlet in the upper and lower layers of each evaporator, that is, from the upper part to the lower part, the refrigerant is removed. Once the lower layer of the evaporator on the frost side is full of refrigerant, it will also be supplied to the evaporator on the cooling side.
In addition, since the volume of the lower layer of each evaporator is smaller than that of the upper layer, the time required for the lower layer to fill with refrigerant is shortened, so there is no possibility of cooling failure. There is no need to particularly increase the amount compared to the conventional method.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, and in the figures, the same components as those of the conventional example are denoted by the same reference numerals. That is, 1 is the show case body, 1
1 and 13 are air passages; 20a and 20b are first and second cold air air passages; 24 is a damper unit;
5 is a compressor, 26 is a condenser, 27a to 27e are electromagnetic valves, 28a to 28d are check valves, 29a, 29b
is an expansion valve, and 30 and 40 are first and second evaporators.

The evaporator 30 consists of an upper layer 31 and a lower layer 32 each having independent refrigerant pipes, ie, refrigerant inlets and outlets. Upper layer 31 is lower layer 3
Compared to No. 2, the volume is larger, and the length of the refrigerant pipe is therefore longer. The upper inlet 32a of the lower layer 32 is connected to the solenoid valve 27a, the lower outlet 32b is connected to the upper inlet 31a of the upper layer 31, and the lower outlet 31b is connected to the solenoid valve 27d. The evaporator 40 also includes an upper layer 41 and a lower layer 42 each having independent refrigerant pipes, that is, an inlet and an outlet for the refrigerant.
The upper layer 41 has a larger volume than the lower layer 42, and therefore the length of the refrigerant pipe is also longer. The upper inlet 42a of the lower layer 42 is connected to the solenoid valve 27c, the lower outlet 42b is connected to the upper inlet 41a of the upper layer 41, and the lower outlet 41b is connected to the solenoid valve 27e.

The evaporator 30 has an upper layer 3 above the air passage 20a.
1 is placed and fixed, and the evaporator 40
is arranged and fixed below the air passage 20b with the upper layer 41 facing upward.

Next, to explain the operation, in the first operation mode, the liquid refrigerant that has passed through the solenoid valve 27a enters the lower layer 32 of the evaporator 30 from the inlet 32a, first warms and defrosts the lower layer 32, and then exits 32b It enters the upper layer 31 through the inlet 31a, warms it and defrosts it, and connects the check valves 28c, 28 through the outlet 31b.
b, the lower layer 4 of the evaporator 40 via the expansion valve 29b
2. It is further sent to the upper layer 41 and cooled.

In addition, in the second operation mode, the solenoid valve 27
The liquid refrigerant that has passed through c enters the lower layer 42 of the evaporator 40 from the inlet 42a, first warms and defrosts the lower layer 42, and then enters the upper layer 41 from the outlet 42b through the inlet 41a, warms and defrosts it. , exit 41
b is sent to the lower layer 32 and further to the upper layer 31 of the evaporator 30 via the check valves 28d and 28a and the expansion valve 29a, where it is cooled.

In the third operation mode, the refrigerant that has passed through the electromagnetic valve 27b is sent to the lower layer 32 through the check valve 28a and the expansion valve 29a, and on the other hand, is sent to the lower layer 42 through the check valve 28b and the expansion valve 29b, and then to the upper layer. 3
1 and 41, and the evaporators 30 and 40 are cooled.

According to the embodiment, the liquid refrigerant is first transferred to the lower layer 32, 42 of the evaporator, e.g. 30 or 40, during defrosting.
The frost at the bottom of the evaporator, which was previously difficult to melt, can be removed in a short time. In addition, the lower layers 32, 4 of the evaporator which were previously defrosted
The air around 2 is heated faster, but the air warmed by the lower layers 32 and 42 rises to the top of the evaporator, that is, around the upper layers 31 and 41.
defrosting of the upper layers 31, 41 can be promoted;
That is, the heat of the refrigerant can be used effectively. Also, the air warmed in the lower layers 32, 42 rises, and the heat of the air is taken away when the upper layers 31, 41 are defrosted, resulting in a lower temperature.
0 The temperature of the air above becomes lower, and the other evaporator 4
It is possible to reduce the influence of 0.0, 30 on the cold air and the temperature inside the refrigerator, and improve the cooling efficiency. Also,
Since the refrigerant flows from the top to the bottom in the upper layers 31, 41 and the lower layers 32, 42, as in the conventional case,
When the lower layers 32, 42 of the evaporators 30, 40 on the defrosting side are filled with refrigerant, the refrigerant is also supplied to the evaporators 40, 30 on the cooling side, and
0, the volume of the lower layers 32, 42 is smaller than that of the upper layers 31, 41, so the time required for the lower layers 32, 42 to become full of refrigerant is short, and therefore there is no possibility of cooling failure. Further, there is no need to particularly increase the amount of refrigerant to be sealed compared to the conventional case.

(Effect of the invention) As explained above, the invention includes two systems of evaporators arranged in the air passage inside the case body, and the refrigerant from the condenser is directly sent to the first evaporator for defrosting. The refrigerant is passed through the expansion valve to the second
In the first mode, the refrigerant from the condenser is sent directly to the second evaporator for cooling operation, and in the second mode, the refrigerant is sent to the first evaporator through the expansion valve for cooling operation. and a third mode in which refrigerant from the condenser is sent to the first and second evaporators for cooling operation through an expansion valve. As the second evaporator, an evaporator is used, which consists of two upper and lower layers each having an independent refrigerant inlet and outlet at the upper and lower parts, and in which the volume of the lower layer is smaller than that of the upper layer, and the refrigerant of the condenser etc. is first sent to the lower layer of the evaporator from the upper inlet to the lower outlet, and then to the upper layer from the upper inlet to the lower outlet. Therefore, when defrosting, the evaporator is The air is warmed and defrosted by the liquid refrigerant from the lower part of the evaporator, and the air warmed by the lower part of the evaporator after defrosting rises to the upper part of the evaporator. Frost is promoted, the heat of the liquid refrigerant can be effectively used during defrosting, the defrosting time can be shortened, and the air warmed by the lower part of the evaporator is heated by the evaporator. When heating the upper part, the heat is taken away and the temperature becomes lower, so there is no need to raise the temperature of the evaporator during defrosting more than necessary.
In addition, the temperature of the air cooled by the other evaporator does not increase, so the influence on the internal temperature can be reduced, and the cooling efficiency can be increased. In the upper and lower layers, the refrigerant flows from the upper inlet to the lower outlet, that is, from the top to the bottom, so when the lower layer of the evaporator on the defrosting side is full of refrigerant, it is also supplied to the evaporator on the cooling side. In addition, since the volume of the lower layer of each evaporator is smaller than that of the upper layer, it takes less time for the lower layer to fill up with refrigerant, thus preventing cooling failure. Further, there are advantages such as there is no need to particularly increase the amount of refrigerant to be sealed compared to the conventional method.

[Brief explanation of the drawing]

The drawings are for explaining the present invention, and FIGS. 1 and 2 show an embodiment of the show case of the present invention, FIG. 1 is a side sectional view, and FIG. 2 is a schematic configuration diagram of a refrigerant circuit. 3 to 5 show an example of a conventional show case, with FIG. 3 being a sectional side view, FIG. 4 being a schematic configuration diagram of a refrigerant circuit, and FIG. 5 being an enlarged sectional view of a damper unit. 1...Sho case body, 11, 13...Air passage, 20a, 20b...Cold air air passage, 24...
Damper unit, 24c... Damper, 25...
...Compressor, 26...Condenser, 27a-27e...
Solenoid valve, 28a...28d...Check valve, 29a,
29b...Expansion valve, 30,40...Evaporator, 3
1,41...upper layer, 32,42...lower layer, 31
a, 32a, 41a, 42a...entrance, 31b,
32b, 41b, 42b...Exit.

Claims (1)

[Claim for Utility Model Registration] It includes two systems of evaporators arranged in the air passage inside the case body, and the refrigerant from the condenser is directly sent to the first evaporator for defrosting operation, and the refrigerant is transferred to the expansion valve. In the first mode, the refrigerant from the condenser is directly sent to the second evaporator for defrosting operation, and the refrigerant is passed through the expansion valve to the second evaporator for cooling operation.
A refrigerant circuit having at least three operating modes: a second mode in which the refrigerant is sent to the first and second evaporators for cooling operation; and a third mode in which the refrigerant from the condenser is sent to the first and second evaporators through the expansion valve for cooling operation. In a show case equipped with a first and second evaporator, the first and second evaporators are made up of two layers, upper and lower, each having an independent refrigerant inlet and outlet at the upper and lower parts, and the volume of the lower layer is smaller than that of the upper layer. Using an evaporator, the refrigerant from the condenser is first sent to the lower layer of the evaporator from its upper inlet to its lower outlet, and then to the upper layer from its upper inlet to its lower outlet. A show case featuring what has been done.