JPH01239357A - Refrigerator - Google Patents

Abstract

PURPOSE:To shorten the time of defrosting by providing a control valve which closes temporarily when starting defrosting operation between an evaporator and compressor. CONSTITUTION:When frost attaches an evaporator 22 on one side, the rotation of its fan 24 is stopped, and at the same time firstly an opening and closing valve 26 on one side is switched from closing to opening and a control valve on the other side is switched from opening to closing by the signal from a controller 51. By those switchings the liquid coolant in a liquid receiving vessel 4 flows into an evaporator 22 on one side through the opening and closing valve 26 on one side, but the liquid coolant which flew into the evaporator 22 on one side is stored as it is in the evaporator 22 on one side and a large heat quantity which the liquid coolant has starts melting the frost that attaches the one side evaporator 22.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to defrosting of refrigeration equipment.

(b) Conventional technology Japanese Patent Publication No. Sho 62-55592 is known as a refrigeration system incorporated into a showcase or a prefabricated refrigerator.

The refrigeration system disclosed in this publication connects a plurality of coolers (evaporators) in parallel, and cools the inside of the refrigerator by flowing a refrigerant through these coolers. If frost builds up on these coolers, it is necessary to perform defrosting operation. In this case, refrigerant is alternately flowed through these coolers to melt the frost that has adhered to them. ing.

(c) Problems to be Solved by the Invention According to this defrosting method, if the refrigerant flowing into one of the coolers is liquid at the start of defrosting operation, the amount of heat that the liquid refrigerant has is sufficient. There was a risk that the liquid refrigerant would flow to the other cooler without being transmitted to the frost (before the heat exchange effect was sufficiently performed). Therefore, there was a problem that the defrosting time became long.

The present invention aims to solve the above problems.

(2) Means for Solving the Problems In order to achieve this object, the present invention disposes a control valve that is temporarily closed at the start of defrosting operation between the evaporator and the compressor. be.

Further, the refrigerant pipe on the outlet side of the condenser is branched, a pressure reducer and an evaporator are connected in series to each of these branch pipes, and the outlet ends of the defrosting pipes are connected to each of these branch pipes. The above-mentioned control valve is arranged in the pipe.

(E) Function By temporarily storing the liquid refrigerant that has flowed into the evaporator at the start of defrosting operation, the heat of this liquid refrigerant will first begin to melt the frost, and then the refrigerant from the condenser will be evaporated. Defrost by letting it flow into the container.

Moreover, by connecting such evaporators in parallel and defrosting these evaporators individually, even when one evaporator is in defrosting operation, the other evaporator can continue cooling operation.

(f) Example In Fig. 1, 1 is a compressor, 2 is a condenser, 3 is a heat exchange fan for this condenser, 4 is a liquid receiver, and 5 is a pipe on the outlet side of this liquid receiver for cooling. Connected to unit 6. This cooling unit 6 is housed in a prefabricated refrigerator (not shown) and cools the inside of the refrigerator. A suction pipe 7 extends from the cooling unit 6 and is connected to the compressor 1 via a flow control valve 8 and an accumulator 9. 10 is a controller for this flow control valve 8, and a sensor 1 installed inside the refrigerator.
The opening degree of the flow control valve 8 is controlled according to the humidity detected in step 1.

In the cooling unit 6, 12 is a first electromagnetic valve disposed on the outlet side pipe 5 of the liquid receiver 4, 20° and 30 are branch pipes of this outlet side pipe 5, and the respective branch chambers 20. A pressure reducing device 21.31, an evaporator 22.32, and a control valve 23.33 are connected in series to 30. Fans 24.34 are individually arranged in these evaporators 22.32. One pressure reducing device 21 includes one expansion valve (pressure reducer) 2
5 and one on-off valve 26, and this on-off valve 26 is arranged in a first conduit 50 that bypasses one expansion valve 25. The temperature sensing portion 27 of one of the expansion valves 25 is attached to the outlet pipe of one of the evaporators 22. The other pressure reducing device 31 is composed of the other expansion valve (pressure reducer) 35 and the other on-off valve 36, and the other on-off valve 36 is connected to the first pipe line 5 that bypasses the other expansion valve 35.
It is located at 0. The temperature sensing portion 37 of the other expansion valve 35 is attached to the outlet pipe of the other evaporator 32. 40 is a defrosting pipe, and one end 41 is connected between the condenser 2 and the liquid receiver 4. This pipe line is branched, and one defrosting pipe line 28 is connected between one evaporator 22 and one control valve 23 via one defrosting on-off valve 29, and the other defrosting line 28 is connected between one evaporator 22 and one control valve 23. The utility pipe line 38 is connected between the other evaporator 32 and the other control valve 33 via the other defrosting on-off valve 39 .

A refrigeration system is made up of such refrigeration equipment, and during cooling operation, defrosting operation, and pump-down operation, the various solenoid valves, control valves, and opening/closing valves mentioned above are controlled by the controller 51 as shown in FIG. Opening/closing controlled.

First, during cooling operation, the first solenoid valve 12 and one control valve 23
and the other control valve 33, and close the one on-off valve 26, the other on-off valve 36, the one defrosting on-off valve 29, and the other defrosting on-off valve 39 (see Fig. 2). 1), the refrigerant discharged from the compressor 1 is caused to flow as shown by the solid line arrow in FIG. That is, the inside of the refrigerator is cooled by flowing refrigerant in parallel to the two evaporators 22 and 32.

For example, if frost forms on one of the evaporators 22,
The rotation of the fan 24 of this one evaporator 22 is stopped, and one on-off valve 26 is first switched from closed to open, and one control valve 23 is switched from open to closed (second sum part of the figure). Due to this switching, the liquid refrigerant in the liquid receiver 4 flows into one evaporator 22 via one of the on-off valves 26, but due to the closing of one of the control valves 23 and the - side defrosting on-off valve 29, one The liquid refrigerant that has flowed into the evaporator 22 is stored as it is in this one evaporator 22, and the large amount of heat of this liquid refrigerant begins to melt the frost that has adhered to this one cooler 22 (see one point in Figure 1). (dashed arrow). A few seconds later, the first electromagnetic valve 12 is changed from open to closed, and one of the defrosting on-off valves 29 is changed from closed to open (part 2 in FIG. 2). Then, the refrigerant from the condenser 2 is passed through one defrosting pipe 28 to one evaporator 22 -> one on-off valve 26 - the other expansion valve 35 - the other evaporator 32 - the other electromagnetic valve 33 -> flow rate. Control valve 8 and flow (dashed line arrow in Figure 1)
.

In this way, during defrosting operation, first, by opening one of the on-off valves 26, the first pipe line 50 acts as a defrosting pipe line, and the night refrigerant in the liquid receiver 4 is transferred to the outlet side pipe 5 and one side. Branch pipe 20
At the same time, the refrigerant flowing into one evaporator 22 is temporarily stored in this evaporator 22 by closing one control valve 23 and one defrosting on-off valve 29. After that, the first solenoid valve 12 is closed and -
By opening the one defrosting on-off valve 29, the refrigerant from the condenser 4 flows into one evaporator 22 via the defrosting pipe 40.28, and the refrigerant flowing out from this evaporator 22 is caused to flow into the first evaporator 22. Pipe line 50 → One branch pipe 20 - Other branch v30 →
The other expansion valve 35 is made to flow with the other evaporator 32. The cooling operation is continued by the cooling action of the other evaporator 32.

After removing the frost from one of the evaporators 22 by the above-mentioned defrosting operation, it is necessary to pump down the refrigerant in this one evaporator 22, and in this case, one of the defrosting on-off valves must be pumped down. 29 (the part @ in Fig. 2), the refrigerant in one evaporator 22 is transferred to one on-off valve 26 and the other expansion valve 3.
5 to the other evaporator 32 or accumulator 9. After the pump down is completed, one control valve 2
3 is opened (the part marked ■ in Fig. 2), and the cooling operation returns to the same as described above (the part marked ■ in Fig. 2). At this time, the operation of the fan 24 of one of the evaporators 22 starts somewhat later than the restart of the cooling operation.

Even when frost adheres to the other evaporator 32, the other on-off valve 36 is activated by a signal from the controller 51, similar to the defrosting operation described above.
can be opened to allow the first pipe line 50 to function as a defrosting pipe line. In addition, by closing the other control valve 36 (the part marked ■ in FIG. 2), the refrigerant flows as indicated by the dashed-dotted line arrow in FIG. to be stored in Thereafter, by closing the first solenoid valve 12 and opening the other defrosting on-off valve 39 (part ■ in FIG. 2),
The refrigerant from the condenser 2 is made to flow into the other evaporator 32.\\ (3rd fyJ broken line arrow). Also, when the pump is down, the other defrosting on-off valve 39 is closed (section ■ in Figure 2) to remove the refrigerant in the other evaporator 32, and then the other solenoid valve 33 is opened. (Part marked ■ in Figure 2)
, return to cooling operation (solid line arrow in Figure 3). At this time as well, the operation of the fan 34 of the other evaporator 32 starts somewhat later than the restart of this cooling operation. In addition, in FIG. 3, solid line arrows indicate the flow of refrigerant during cooling operation.

According to this embodiment, the first pipe line 50 corresponds to the defrosting pipe line at the time of starting the defrosting operation. Also, when starting the defrosting operation, with one and the other on-off valves 26 and 36 closed,
When one and the other control valves 29.39 are opened, high-temperature refrigerant is guided to the evaporator 22.32 via the defrosting pipes 40, 28.38 from the start of the defrosting operation. In this way, at the start of defrosting operation, high-temperature refrigerant is focused on the evaporator 22, 32 and the expansion valves (fi pressure devices) 25, 35
Alternatively, the evaporators 22 and 3 can be viewed from either direction from the compressor 1.
It is also possible to flow it into 2.

Next, a refrigeration system having one evaporator will be explained using FIG. 4. Here, parts that are the same as those in the embodiment shown in FIG. 1 are given the same reference numerals, and their explanations will be omitted. 60 is a defrosting pipe bypassing the pressure reducer 61, and the inlet end 6 of this pipe
2 is connected between the condenser 2 and the pressure reducer 61, and the outlet end 63 is connected between the pressure reducer 61 and the evaporator 64. A first control valve 65 is disposed in this conduit 60. A second control valve 66 is arranged between the evaporator 64 and the compressor 1.

During the cooling operation, the first control valve 65 is closed, the second control valve 66 is opened, and the refrigerant flows as indicated by the solid line arrow. Next, during defrosting operation, the first control valve 65 is first opened, the second control valve 66 is closed, and the liquid refrigerant in the condenser 2 is transferred to the defrosting pipe 6.
0 through the evaporator 64 (bypassing the fi pressure device 61)
send it inside. Here, by closing the second control valve 66, the saliva refrigerant is sent into the evaporator 64.
The large amount of liquid refrigerant (compared to gas refrigerant) stored in
The heat begins to melt the frost. Thereafter, by opening the second control valve 66, the refrigerant is circulated as indicated by the broken line arrow. Note that the inlet end of the defrosting pipe may be connected between the compressor and the condenser as shown by a chain line.

Further, as shown in FIG. 5, another defrosting pipe 67 is provided, and its inlet end 68 is connected to the outlet side pipe 69 of the condenser 2, and its outlet end 70 is connected to the outlet side pipe 71 of the evaporator 64. A third control valve 72 may be arranged in this defrosting pipe line 67 and controlled as follows. First, during cooling operation, the first.
The second and third control valves 65, 66, and 72 are closed to allow the refrigerant to flow in the direction of the solid arrow. During defrosting operation, first
With the first and second control valves 65 and 66 closed, only the third control valve 72 is opened, and the liquid refrigerant in the condenser 2 is passed through the defrosting pipe 67 to the outlet side pipe of the evaporator 64. 71 into this evaporator 64 (dashed line arrow).

The refrigerant sent here is passed through the first and second control valves 65.
．． 66 is closed, the frost accumulates in the evaporator 64 and begins to melt the frost. After that, the third control valve 72 is closed and the first control valve 72 is closed.
At the same time, the second control valves 65 and 66 are opened to circulate the refrigerant (-dotted chain arrow).

<g) Effects of the invention As described above, the present invention temporarily stores the liquid refrigerant that has flowed into the evaporator at the start of defrosting operation of the evaporator, so that the large amount of heat ( (Compared to gas refrigerant), the defrosting time can be shortened because the frost starts to melt.

Moreover, if a plurality of such evaporators are connected in parallel, even when one evaporator is in defrosting operation, the other evaporator can continue to perform cooling operation.

[Brief explanation of the drawing]

Figures 1 to 3 show a first embodiment of the refrigeration system of the present invention, Figures 1 and 3 are refrigerant circuit diagrams showing different operating states, and Figure 2 shows the operation control operation of this equipment. An explanatory diagram showing,
Fig. 4 is a refrigerant circuit diagram showing the second embodiment, and Fig. 5 is a refrigerant circuit diagram showing the third embodiment.
It is a refrigerant circuit diagram showing an example of. 1... Compressor, 2... Condenser, 20.30.
...Branch pipe, 22,32.64...Evaporator, 2
3,33.66.72...control valve, 25,35.
61... pressure reducer, 28.38, 40, 50.60
... Defrost pipe.

Claims (1)

[Claims] 1. A refrigeration cycle is formed by sequentially connecting a compressor, a condenser, a pressure reducer, and an evaporator with refrigerant pipes, and the high-temperature refrigerant of this refrigeration cycle is evaporated during defrosting operation of the evaporator. A refrigeration system provided with a defrosting conduit for flowing water to a container, characterized in that a control valve that temporarily closes at the start of the defrosting operation is disposed between the evaporator and the compressor. . 2. Branch the refrigerant pipe on the outlet side of the condenser, connect a pressure reducer and an evaporator in series to each of these branch pipes, and connect the outlet ends of the defrosting pipes to each of these branch pipes. The refrigeration system according to claim 1, further comprising a control valve disposed in the pipe. 3. The refrigeration system according to claim 1, further comprising a control valve for flowing the refrigerant flowing out from one evaporator to the other evaporator during defrosting operation.