JPH07120116A - Cooling system - Google Patents

Abstract

PURPOSE:To prevent generation of abnormal sound from a 1 solenoid valve without applying counter pressure to the valve in an injection circuit even in a defrosting operation of low atmospheric conditions and to prevent damage of the valve. CONSTITUTION:The cooler comprises a main circuit having a compressor 1, a condenser 2, a check valve 16, a first throttle unit 15 and an evaporator 8, a defrosting circuit having a second throttle unit 18 and a hot gas coil 12, an injection circuit having a solenoid valve 20 and a third throttle unit 21 for preventing overheating of the compressor 1 during cooling, and a three-way valve 17 for switching a cooling operation and the defrosting operation. An outlet 19a of the injection circuit 19 is provided between the valve 16 of the main circuit and an inlet of the unit 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device having a compressor cooling injection circuit and a defrosting circuit.

[0002]

9 and 10 show a conventional cooling device of this type. In the figure, 1 is a compressor, 2 is a condenser, and 3 is a blower for a condenser, and these are arranged on a unit base 5 fixed on a top panel 4 of a refrigerator. Further, a through hole 6 is provided on one side of the unit base 5, and the periphery of the through hole 6 is surrounded by a heat insulating box 7. In the heat insulating box 7, an evaporator 8, an evaporator blower 9, and a drain pan 1 are provided.
0 is arranged and fixed to the connecting member 11. The connecting member 11 is connected to the unit base 5.
FIG. 11 shows a refrigerant circuit of the system shown in Japanese Patent Application No. 503240, in which 15 is a first expansion device, 16 is a check valve, and 17 is a high temperature gas discharged from the compressor 1 as a condenser. From the side to the defrosting circuit, 18 is a second expansion device for increasing the compressor input, 19 is an injection circuit for circulating the supercooled liquid to the compressor 1, 20, 2
Reference numeral 1 denotes a solenoid valve and a third throttle device, which are connected to the injection circuit 19 in the middle thereof. Also, the drain pan 10
A hot gas coil 12 that circulates the discharge gas of the compressor 1 is fastened to the lower part of the with a screw 14 via a pressing plate 13.

In such a structure, when performing a cooling operation, when the temperature of the compressor 1 rises and becomes equal to or higher than a specified temperature, a discharge gas detection thermostat (not shown) operates and the solenoid valve 20 opens. The supercooled liquid condensed in the condenser 2 passes through the electromagnetic valve 20, is decompressed and lowered in temperature by the third expansion device 21, and is circulated to the compressor 1 to suppress the temperature rise of the compressor 1. Also,
When the cooling operation is continued for a certain period of time, frost is formed on the evaporator 8. Therefore, when the defrost timer (not shown) operates, the three-way valve 17 is switched, and the high-temperature gas discharged from the compressor 1 passes through the second expansion device 18, the hot gas coil 12, and the evaporator 8 and the compressor 1 Is inhaled and melts the frost. Further, at this time, since the three-way valve 17 blocks the flow of the refrigerant into the condenser 2, the supercooled liquid is not supplied to the injection circuit 19.

[0004]

Since the conventional cooling device is configured as described above, when the defrosting operation is performed under the condition that the outside air temperature is lowered such as in winter, the condenser outlet pressure becomes Since the saturation pressure is equivalent to the outside air temperature, the injection circuit inlet (electromagnetic valve inlet) pressure taken out from the condenser outlet pipe is also reduced. On the other hand, the injection circuit outlet (compressor injection port) pressure was slightly lower than the compressor discharge pressure, which could not occur during the cooling operation, and the injection inlet and outlet pressure reversals occurred, and the injection circuit was connected to the injection circuit. Reverse pressure is applied to the solenoid valve. At this time, because there is pressure pulsation at the injection circuit outlet (compressor injection port), the solenoid valve causes chattering and an abnormal noise is generated. The part will be worn and the solenoid valve will be damaged. Further, if the cooling operation is continued while the electromagnetic valve is damaged, liquid backing and liquid compression operation of the compressor may occur depending on the case, and finally a problem of the compressor occurs.

The present invention has been made in order to solve the above-mentioned problems, and prevents back pressure from being applied to the solenoid valve in the injection circuit during the defrosting operation regardless of the outside air temperature. An object of the present invention is to provide a cooling device that prevents the occurrence of electromagnetic valve defects and compressor defects due to back pressure during defrosting.

[0006]

[Means for Solving the Problems] Claim 1 according to the present invention
According to this cooling device, the discharge hot gas provided between the main circuit in which the compressor, the condenser, the check valve, the first expansion device, and the evaporator are sequentially connected, and the compressor and the condenser are provided. A second throttle device between the switching valve for switching and the inlet portion of the evaporator;
Cooling provided with a defrosting circuit connected via a hot gas coil, and an injection circuit including an on-off valve and a third expansion device for circulating the liquid refrigerant taken out from the condenser outlet during the cooling operation to the compressor The device is provided with a control circuit for opening the on-off valve in the injection circuit during defrosting.

According to the cooling device of the second aspect, the main circuit in which the compressor, the condenser, the check valve, the first expansion device, and the evaporator are sequentially connected, the compressor, and the condenser. Between the switching valve for switching the discharged high temperature gas provided between the evaporator and the inlet portion of the evaporator, the defrosting circuit connected via the second expansion device and the hot gas coil, and during the cooling operation, In a cooling device formed of an injection circuit for circulating the liquid refrigerant flowing out of the condenser to the compressor via an opening / closing valve and a third expansion device, the liquid refrigerant outlet of the injection circuit is provided with the check valve. And the first diaphragm device.

According to the cooling device of the third aspect, in the liquid refrigerant outlet of the injection circuit provided between the check valve and the first expansion device, during the defrosting operation,
A control circuit for opening the on-off valve of the injection circuit is provided.

According to the cooling device of the fourth aspect, the main circuit in which the compressor, the condenser, the check valve, the first expansion device, and the evaporator are sequentially connected, the compressor, and the condenser. A defrosting circuit connected between a switching valve for switching the discharged high temperature gas and the evaporator inlet portion via a second expansion device and a hot gas coil, and a defrosting circuit during the cooling operation. In a cooling device formed of an injection circuit for circulating the liquid refrigerant taken out from the condenser outlet through the on-off valve and a third expansion device to the compressor, an on-off valve and a third valve in the injection circuit are provided. A check valve is provided between the throttle devices.

According to the cooling device of the fifth aspect, the main circuit in which the compressor, the condenser, the check valve, the first expansion device, and the evaporator are sequentially connected, the compressor, and the condenser. A defrosting circuit connected via a second expansion device and a hot gas coil between the switching valve for switching the discharged high temperature gas and the evaporator inlet, and the condensing during cooling operation. A cooling device formed of an injection circuit for circulating the liquid refrigerant taken out from the outlet of the reactor to the compressor via an opening / closing valve and a third expansion device, wherein a third expansion device and an opening / closing valve in the injection circuit are provided. A bypass circuit for bypassing is provided.

[0011]

In the cooling device of claim 1, between the compressor, the condenser, and the main circuit in which the compressor, the condenser, the check valve, the first expansion device, and the evaporator are sequentially connected. A defrosting circuit connected via a second expansion device and a hot gas coil between the switching valve for switching the discharged hot gas and the evaporator inlet, and the liquid taken out from the condenser outlet during the cooling operation. In a cooling device formed of an injection circuit for circulating a refrigerant to the compressor through an on-off valve and a third expansion device, a control for forcibly opening the on-off valve in the injection circuit during defrosting operation. Therefore, the back pressure accompanied by pulsation is not applied to the outlet side of the on-off valve, chattering of the on-off valve can be prevented, abnormal noise can be generated, and damage to the valve seat portion can be prevented.

In the cooling device of the second aspect, the liquid refrigerant outlet of the injection circuit is provided between the check valve and the first expansion device, so that the pressure at that portion is controlled by the defrosting circuit. Since it will be almost equal to the outlet pressure of, it will not be affected by the outside air temperature and will not fall to the saturation pressure equivalent to the outside air temperature, and the possibility that it will fall below the pressure at the injection outlet (compressor injection port) is small. Become.

Further, in the cooling device of the third aspect, the opening / closing valve in the injection circuit is forcibly opened during defrosting, so that even if a reverse pressure is applied to the opening / closing valve under certain conditions. , The valve seat of the on-off valve does not cause chattering. Therefore, the on-off valve is not damaged.

In the cooling device of the fourth aspect, by providing a check valve between the third expansion device and the opening / closing valve in the injection circuit, the outside air temperature is lowered and the injection circuit inlet (condensation) Even if the partial pressure at the device outlet is low and the partial pressure at the injection circuit outlet (compressor injection port) is high, the flow is stopped at the check valve outlet side, so a reverse pressure is applied to the on-off valve in the injection circuit. Can be prevented. Therefore, the on-off valve can be prevented from being damaged.

In the cooling device of the fifth aspect, by providing the third throttle device of the injection circuit and the bypass circuit for bypassing the on-off valve, the inlet of the on-off valve in the injection circuit during defrosting, Since the pressures at the outlets become substantially equal, no back pressure is generated from the outlet side of the on-off valve toward the inlet side. Therefore, the on-off valve can be prevented from being damaged.

[0016]

【Example】

Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an injection port 1a.
Attached compressor, 2 a condenser, 2a and 2b condenser inlet and outlet respectively, 8 an evaporator, 15 a first throttling device, 16
Is a check valve, 17 is a three-way valve as a switching valve, and 22 is a defrosting circuit composed of the second expansion device 18 and the hot gas coil 12. In addition, the injection circuit 19
Is formed by an electromagnetic valve 20 as an opening / closing valve and a third expansion device 21. 2 shows a refrigerant circuit including the internal structure of the compressor 1 (rotary compressor). In FIG. 2, 1a is an injection port, 1b
Is a discharge port, and 1c is a suction part. Others are shown in Figure 1.
Is the same as.

FIG. 3 shows a main part of a control circuit of the cooling device according to the first embodiment. Reference numeral 23 is a normally open contact (a contact) of the defrosting relay controlled by the defrosting timer. In this embodiment, 24 detects the refrigerant temperature at the outlet of the evaporator during the defrosting operation, and is ON when the detected temperature is equal to or higher than a predetermined temperature and O when
Defrosting thermostat FF, 25 is a relay (X ₂ ) connected in series with the defrosting thermostat 24,
Reference numeral 17a is an electromagnetic coil for the three-way valve 17. 26 is a compressor ON / OFF relay, 27 is a discharge gas detection thermostat, 28 is a relay connected in series with the discharge gas detection thermostat 27, 28a is a normally closed contact (b contact), and 9a is a blower for an evaporator. The motor, 20a, is an injection solenoid valve coil. In the configuration as described above, the refrigerant temperature at the outlet of the evaporator 8 drops below a predetermined temperature and the defrosting thermostat 24 is turned off.
When the contact 23 of the defrosting relay is turned on, the three-way valve electromagnetic coil 17a is excited to switch the three-way valve 17, and the high temperature gas refrigerant discharged from the compressor 1 is discharged from the defrosting circuit 22 to the evaporator. 8 are supplied. In the defrosting circuit 22 and the evaporator 8, defrosting is performed by the supplied high temperature refrigerant.

On the other hand, when the discharge gas temperature rises excessively during the cooling operation and becomes higher than a predetermined temperature, the discharge gas detection thermostat 27 opens, so that the injection solenoid valve 20 opens via the relay (X6) 28. Then, the supercooled liquid at the outlet of the condenser flows into the injection circuit 19. The liquid refrigerant flowing into the injection circuit 19 is the third
It is decompressed by the expansion device 21 and is mixed with the high temperature gas refrigerant during compression through the compressor injection port portion 1a to lower the temperature of the gas refrigerant discharged from the discharge port portion 1b. By the way, in the present invention, as shown in FIG. 3, during the defrosting operation, the relay (X1) 29 is excited regardless of the discharge gas temperature, so that the contact (X1) 29
1) The injection solenoid valve coil 20a is constantly excited via 29a, and the solenoid valve 20 is open.

As described above, during the cooling operation (the flow of the refrigerant is shown by the solid line in FIGS. 1 and 2), when the temperature of the discharge port portion 1b of the compressor 1 rises above the specified value, the discharge gas detection thermostat 27. Is operated, the solenoid valve 20 in the injection circuit 19 is opened, and as shown in FIG. 4, supercooling is performed from the condenser outlet portion 2b having a high pressure to the compressor injection port portion 1a having a lower pressure than the condenser outlet portion 2b. Liquid flows in. (P2b> P1a) As a result, the temperatures of the discharge port portion 1b of the compressor 1 and the compressor 1 as a whole can be suppressed below a specified value. At this time, since the solenoid valve 20 allows only one direction, the condenser outlet side is connected to the inlet side of the solenoid valve 20 in the mounting direction. On the other hand, during defrosting operation (in FIG. 1 and FIG. 2, the flow of the refrigerant is shown by a broken line) Three-way valve 1
Since the flow path is switched by 7, the refrigerant does not flow into the condenser 2 and the check valve 16 is provided at the condenser outlet, so that the injection inlet taken out between the condenser 2 and the check valve 16 is provided. The pressure of the part becomes the outside air temperature saturation pressure, and particularly when the outside air is low (for example, 0 ° C.), the pressure becomes lower than the pressure of the injection port portion 1b. Therefore, when the solenoid valve 20 is closed as in the conventional example, the solenoid valve 20 is closed. Reverse pressure is applied intermittently from the outlet side to the inlet side of the valve, causing chattering in the valve part, which leads to damage to the valve and valve seat part, and abnormal noise generation. The solenoid valve 20 is controlled to open.

Example 2. Embodiment 2 of the present invention is shown in FIG. The injection port 19a of the injection circuit 19 is provided between the check valve 16 and the first expansion device 15. Others are the same as the embodiment of FIG. As a result, even during defrosting, the pressure at the injection inlet 19a changes from the pressure at the discharge port 1b to the pressure loss amount of the second expansion device 18 and the hot gas coil 12 in the defrosting circuit as shown in FIG. The decrease in pressure is less than that, and is not affected by the decrease in outside air temperature, and the reverse pressure applied to the solenoid valve 20 due to the decrease in outside air temperature is eliminated.

Example 3. Further, in the cooling device shown in the second embodiment, the solenoid valve 20 is always opened during the defrosting operation by the control circuit shown in FIG. 3, so that the second expansion device 18 and the hot gas in the defrosting circuit are It is possible to prevent the back pressure from being applied to the solenoid valve 20 regardless of the pressure loss of the coil 12.

Example 4. Example 4 of the present invention is shown in FIG. Solenoid valve 2 forming the injection circuit 19
A check valve 30 is connected between 0 and the third expansion device 21. Others are the same as the embodiment of FIG. by this,
During defrosting, especially under low outside air conditions, the compressor injection port unit 1 moves from the injection circuit inlet unit 19a.
Although the pressure on the side of a is higher, the check valve 30 connected to the outlet side of the solenoid valve 20 has a function of preventing the inflow of the refrigerant from the injection port 1a side, so that the check valve 30 is connected to the solenoid valve 20. There is no pressure.

Example 5. Example 5 of the present invention is shown in FIG. In the figure, reference numeral 31 is a bypass circuit for bypassing the solenoid valve 20 and the third expansion device 21 in the injection circuit 19. In this bypass circuit, a check valve 32 is attached from the injection port 1a side toward the injection circuit inlet 19a side. by this,
Even when the pressure at the injection port portion 1a of the compressor 1 becomes higher than that at the injection circuit inlet 19a during defrosting, especially under low outside air conditions, the refrigerant is bypassed through the bypass circuit 31, so the solenoid valve 20 The pressure at the inlet and outlet of is equalized. Therefore, the reverse pressure applied to the solenoid valve 20 due to the low outside air temperature is eliminated. Further, during the cooling operation, if the discharge gas temperature rises excessively, the flow stops at the inlet of the check valve 32, so that the refrigerant does not flow into the bypass circuit 31 and passes through the regular injection circuit 19 to the compressor 1. The cooling liquid flows in and functions to prevent overheating.

[0024]

According to the first aspect of the invention, since the on-off valve in the injection circuit is forcibly opened during defrosting of low outside air, a back pressure with pulsation is generated in the outlet of the on-off valve. The chattering of the on-off valve can be prevented,
It is possible to prevent generation of abnormal noise and damage to the on-off valve. Also,
Since the defective parts of the on-off valve are reduced, it is possible to obtain the effect of leading to the protection of the compressor.

According to the second aspect of the present invention, by providing the outlet of the injection circuit between the check valve of the main circuit and the first expansion device, the on-off valve in the injection circuit under the influence of the outside air. Since back pressure is eliminated, chattering of the on-off valve can be prevented, and abnormal noise can be prevented from occurring and damage to the on-off valve can be prevented. Further, since the defective parts of the on-off valve are reduced, it is possible to obtain the effect of protecting the compressor.

According to the invention of claim 3, the injection port of the injection circuit is provided between the check valve of the main circuit and the first expansion device, and the opening / closing valve is opened during the defrosting operation. By doing so, it is possible to more reliably suppress the occurrence of back pressure applied to the on-off valve, and it is possible to prevent the occurrence of chattering.

According to the fourth aspect of the present invention, by providing the check valve downstream of the on-off valve in the injection circuit, the flow of the refrigerant to the outlet side of the on-off valve is shut off and the back-pressure is applied to the on-off valve. Can be prevented. Therefore, chattering of the on-off valve can be prevented, and abnormal noise can be prevented and damage to the on-off valve can be prevented. In addition, since the defective parts of the on-off valve are reduced, it is possible to obtain the effect of protecting the compressor.

According to the invention of claim 5, the reverse flow of the injection circuit is bypassed from the outlet side to the inlet side of the on-off valve during defrosting, so that back pressure can be prevented from being applied to the on-off valve and abnormal noise from the on-off valve can be prevented. Can be prevented and damage to the on-off valve can be prevented. In addition, since the defective parts of the on-off valve are reduced, it is possible to obtain the effect of protecting the compressor.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram showing a first embodiment of the present invention.

2 is a compressor internal structure and a refrigerant circuit diagram of Embodiment 1. FIG.

FIG. 3 is a control circuit diagram showing Embodiments 1 and 3 of the present invention.

FIG. 4 is a Mollier diagram when the injection circuit is operating during cooling operation.

FIG. 5 is a refrigerant circuit diagram showing a second embodiment of the present invention.

FIG. 6 is a Mollier diagram showing a pressure state of each part during defrosting operation according to the second embodiment of the present invention.

FIG. 7 is a refrigerant circuit diagram showing Embodiment 4 of the present invention.

FIG. 8 is a refrigerant circuit diagram showing Embodiment 5 of the present invention.

FIG. 9 is a cross-sectional view showing a conventional cooling device.

FIG. 10 is an explanatory diagram of a hot gas coil attachment.

FIG. 11 is a refrigerant circuit diagram showing a conventional cooling device.

[Explanation of symbols]

 1 Compressor 2 Condenser 8 Evaporator 15 1st expansion device 16 Check valve 17 Switching valve 18 2nd expansion device 19 Injection circuit 20 On-off valve 21 3rd expansion device 22 Defrost circuit 30 Check valve 31 Bypass circuit

Claims (5)

[Claims] 1. A main circuit in which a compressor, a condenser, a check valve, a first expansion device, and an evaporator are sequentially connected, the compressor,
From the switching valve for switching the discharge high temperature gas provided between the condensers, via the second expansion device and the hot gas coil,
A defrosting circuit connected to the evaporator inlet and an injection circuit including an on-off valve and a third expansion device for circulating the liquid refrigerant taken out from the condenser outlet to the compressor during a cooling operation. In the cooling device, a control circuit for opening an opening / closing valve in the injection circuit during a defrosting operation is provided. 2. A main circuit in which a compressor, a condenser, a check valve, a first expansion device, and an evaporator are sequentially connected, the compressor,
A defrosting circuit connected between a switching valve for switching the discharge high temperature gas provided between the condensers and the evaporator inlet through a second expansion device and a hot gas coil, and cooling. In operation, in a cooling device formed of an injection circuit that causes the liquid refrigerant that has flowed out of the condenser to flow through the on-off valve and a third expansion device to the compressor, the liquid refrigerant outlet of the injection circuit is reversely A cooling device provided between a stop valve and the first expansion device. 3. The cooling device according to claim 2, further comprising a control circuit for opening an opening / closing valve provided in the injection circuit during defrosting. 4. A main circuit in which a compressor, a condenser, a check valve, a first expansion device, and an evaporator are sequentially connected, the compressor,
A defrosting circuit connected between a switching valve for switching the discharge high temperature gas provided between the condensers and the evaporator inlet through a second expansion device and a hot gas coil, and cooling. During operation, in a cooling device formed by an injection circuit including an opening / closing valve for circulating the liquid refrigerant taken out from the condenser outlet to the compressor, and a third expansion device, an opening / closing valve in the injection circuit and A cooling device, in which a check valve is provided between the throttle devices of 3. 5. A main circuit in which a compressor, a condenser, a check valve, a first expansion device, and an evaporator are sequentially connected, the compressor,
A switching valve for switching the discharge high temperature gas provided between the condensers, a second expansion device between the evaporator inlet portion and a hot gas coil, and a defrosting circuit, and a cooling operation. At times, in a cooling device formed of an injection circuit for circulating the liquid refrigerant taken out from the condenser outlet to the compressor through an opening / closing valve and a third expansion device,
A cooling device comprising a bypass circuit for bypassing a third expansion device and an on-off valve in the injection circuit.