JP2757689B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention suppresses a rise in temperature of discharge gas and compressor lubricating oil by injecting a refrigerant liquid into an intermediate pressure section of a compressor and a refrigerant gas suction line during a refrigeration operation. It relates to a refrigeration system.

[0002]

2. Description of the Related Art A typical prior art of a refrigerating apparatus provided with an injection circuit for injecting a refrigerant liquid for the purpose of lowering a discharge gas temperature and a lubricating oil temperature of a compressor is disclosed in, for example, JP-A-59-217458. It is publicly known from Japanese Patent Publication No. FIG. 2 shows an outline of a refrigeration apparatus including an injection circuit. The refrigerating apparatus includes a compressor 1, a four-way switching valve 2, a condenser 3, an expansion mechanism 4 including a temperature-sensitive expansion valve, an evaporator 5, and an accumulator 8, and further includes a defrost capillary 7, and a refrigerating cycle. A refrigeration circuit is formed in which the refrigeration operation and the defrost operation by the reverse refrigeration cycle are switched. The oil separator 6 has an oil outlet connected to the outlet of the accumulator 8 by a pipeline having a capillary 33. The defrost capillary 7 is connected to the inlet of the temperature-sensitive expansion valve 4 via a dryer 11 and a filter 12 in series. For this defrost capillary 7, a check valve 9 and a receiver 10
Are connected in series. A check valve 13 is connected in parallel to the expansion valve 4. The coil end of the evaporator 5 on the outlet side during cooling is connected to the second switching port of the four-way switching valve 2 via the check valve 14. To the check valve 14, a heater pipe having a drain pan heater 17, in-compartment heaters 16, 16 and a check valve 15 in series is connected in parallel. Inside fan 24, 2
The indoor air flowing with the rotation of 4 is cooled to low temperature by the latent heat of evaporation of the evaporator 5, while the high-pressure refrigerant gas in the condenser 3 flows between the indoor air and the outdoor air flowing with the rotation of the outdoor fan 23. The latent heat of condensation is exchanged with heat to condense and liquefy.

In FIG. 2, a first injection circuit 19 and a second injection circuit 20 are branched from a refrigerant liquid line. The first injection circuit 19 has a first solenoid valve 26 interposed in the thin tube 25, and guides a small amount of the refrigerant liquid flowing through the refrigerant liquid line by opening the first solenoid valve 26, and a compressor including a scroll compressor. The refrigerant liquid is injected into an intermediate portion (becoming an intermediate pressure portion) of the first scroll to operate to cool the compressed gas in the scroll.

On the other hand, the second injection circuit 20
The second electromagnetic valve 28 and the capillary 27 are formed in a refrigerant line connected in series, and a small amount of the refrigerant liquid in the refrigerant liquid line is guided by opening the second electromagnetic valve 28, and the pressure is reduced by the capillary 27. The operation of cooling the lubricating oil stored in the accumulator 8 is performed by injecting the refrigerant liquid into the refrigerant gas suction line connected to the refrigerant inflow side.

[0005]

When the compressor 1 is stopped, the two injection circuits 19 and 20 are connected to the two solenoid valves 2.
6 and 28 are closed to make them inactive. However, if there is even a small leak in the solenoid valves 26 and 28, especially in the case of the first injection circuit 19, the inlet and outlet of the solenoid valve 26
Due to the pressure difference of the outlet pipe, the refrigerant liquid passes through the solenoid valve 26,
When the compressor 1 flows and stays in the scroll of the compressor 1 and is started immediately thereafter, there is a problem that the compressor 1 causes liquid compression and damage to the scroll.

An object of the present invention is to prevent the refrigerant liquid from staying in the compressor even if a refrigerant leaks in a liquid injection circuit connected to the compressor when the compressor is stopped, thereby preventing the liquid from being compressed at the time of start-up and ensuring safety. An object of the present invention is to provide a refrigerating device having high operability.

[0007]

The present invention relates to a refrigeration system comprising a compressor 1, a condenser 3, an expansion mechanism 4, and an evaporator 5 to constitute a refrigeration cycle. The first injection circuit 19 guides the refrigerant liquid in the high-pressure refrigerant liquid line 36 connected to the compressor 1, reduces the pressure in the first capillary 21, and injects the refrigerant into the intermediate pressure section of the compressor 1.
A second injection circuit 20 for guiding the refrigerant liquid in the high-pressure refrigerant liquid line 36, reducing the pressure in the second capillary 22, and injecting the refrigerant into the refrigerant gas suction line 31 connected to the refrigerant outflow side of the evaporator 5; An electromagnetic valve 18 shared by the first and second injection circuits 19 and 20 and provided in series with the first capillary 21 and the second capillary 22 on the upstream side, and closed when the compressor 1 is stopped. A refrigeration apparatus characterized in that:

The present invention is also a refrigerating apparatus in which the solenoid valve 18 is opened to constantly inject the first and second injection circuits 19 and 20 during a refrigerating operation.

[0009]

According to the present invention, during the refrigerating operation, both the injection circuits 19 and 20 are operated simultaneously, and the abnormal increase in the temperature of the discharged refrigerant gas is suppressed by the refrigerant liquid injection operation of the first injection circuit 19. Further, the refrigerant liquid injection action of the second injection circuit 20 suppresses a rise in the temperature of lubricating oil present in the refrigerant liquid storage portion such as an accumulator in the low-pressure suction line.

When the solenoid valve 18 is closed when the compressor 1 is stopped and both injection circuits 19 and 20 are inactive, even if a slight leak may occur in the solenoid valve 18, Since the intermediate pressure on the compressor 1 connection side of the one injection circuit 19 is higher than the low pressure pressure on the suction line connection side of the second injection circuit 20, the refrigerant liquid accumulated in the compressor 1 From the first injection circuit 19 to the second injection circuit 20
And the refrigerant gas flows in the same manner. Therefore, the refrigerant liquid does not accumulate in the compressor 1 and liquid compression does not occur at the time of startup, and safe operation is possible.

According to the present invention, the solenoid valve 18 during the refrigeration operation
Are always open, the first and second capillary 2
Since the resistance of the refrigerants 1 and 22 to the refrigerant gas is large, the amount of the refrigerant flowing by bypass is negligibly small,
Therefore, there is almost no decrease in the refrigerating capacity, and control for suppressing a rise in temperature of the discharged gas or the like is stably performed.

[0012]

1 is a refrigeration circuit diagram of a refrigeration apparatus according to an embodiment of the present invention. 1 includes a compressor 1, a four-way switching valve 2, a condenser 3, an expansion mechanism 4 including a temperature-sensitive expansion valve, an evaporator 5, and an accumulator 8, and further includes a defrost capillary 7, and A refrigeration circuit is formed in which the refrigeration operation by the refrigeration cycle and the defrost operation by the reverse refrigeration cycle are switched.

A scroll compressor is used as the compressor 1. The compressor 1 has a discharge port connected to an inflow port of the four-way switching valve 2 by a pipe 29 having an oil separator 6 and an intake port. The line 30 connects to the outlet of the accumulator 8. The inlet of the accumulator 8 is connected to the outlet port of the four-way switching valve 2 by a conduit 31. on the other hand,
The oil separator 6 has an oil outlet connected to the outlet side of the accumulator 8 by a pipeline 32 having a capillary 33.

The condenser 3 has a coil end connected to the first switching port of the four-way switching valve 2 connected to the inlet side at the time of cooling by a pipe 34, and has a coil end connected to the pipe at the cooling outlet side by a pipe 35. It is connected to one end of the defrost capillary 7.
The other end of the defrost capillary 7 is connected to the inlet of the temperature-sensitive expansion valve 4 by a refrigerant liquid line realized by a pipeline 36 having a dryer 11 and a filter 12 in series. A pipeline having a check valve 9 and a receiver 10 connected in series is connected to the defrost capillary 7 in parallel.

The temperature-sensitive expansion valve 4 has an outlet connected to an end of the coil, which is located on the inlet side of the evaporator 5 at the time of cooling, through a conduit 37. A check valve 13 is connected to the expansion valve 4 in parallel. The evaporator 5 is connected to the second switching port of the four-way switching valve 2 by a pipe 38 having a coil end on the outlet side during cooling via the check valve 14. With respect to the check valve 14, a drain pan heater 17, an internal fan heater 16,
16, heater pipes having check valves 15 in series are connected in parallel. In the refrigerant liquid line 36, a pipe 39 is branched from a location near the defrost capillary 7 in the middle, and an inlet of the solenoid valve 18 is connected to an end of the pipe 39. The solenoid valve 18 has an outlet connected to an inflow side end of the first injection circuit 19 and an inflow side end of the second injection circuit 20.

The first injection circuit 19 has a first capillary 21, and an outlet end of the first capillary 21 is connected to an intermediate pressure portion of the scroll in the scroll compressor 1. The second injection circuit 20 includes a second capillary 22, and an outlet end of the second capillary 22 is branched and connected to, for example, a pipe 31 in the refrigerant gas suction line.

In the refrigerating apparatus of the above embodiment, the compressor 1, the oil separator 6, the four-way switching valve 2, the condenser 3, the four-way switching valve 2 are operated by the solid line valve operation shown in FIG. A refrigeration cycle of the check valve 9, the receiver 10, the dryer 11, the filter 13, the temperature-sensitive expansion valve 4, the evaporator 5, the check valve 14, the four-way switching valve 2, the accumulator 8, and the compressor 1 is formed.
The indoor air flowing with the rotation of the internal fans 24, 24 is cooled to a low temperature by the latent heat of evaporation of the evaporator 5, while
In the condenser 3, the high-pressure refrigerant gas exchanges latent heat of heat with outdoor air flowing with the rotation of the outdoor fan 23 to condense and liquefy.

On the other hand, when the evaporator 5 is to be defrosted, the compressor 1, the oil separator 6, the four-way switching valve 2, and the check valve 1 are switched by switching the four-way switching valve 2 to a valve operation indicated by a broken line.
5, internal fan heater 16, drain pan heater 17,
Evaporator 5, check valve 13, filter 12, dryer 11,
A defrost cycle of the defrost capillary 7, the condenser 3, the four-way switching valve 2, the accumulator 6, and the compressor 1 is formed, and the evaporator 5 performs defrost by sensible / latent heat of hot gas.

During the refrigerating operation, while the compressor 1 is operating, the solenoid valve 18 is opened and the first and second injection circuits 19, 20 are operated. The first injection circuit 19 guides a part of the refrigerant liquid flowing through the high-pressure refrigerant liquid line 36, reduces the pressure to an intermediate pressure by the first capillary 21, and reduces the reduced pressure of the refrigerant liquid to a scroll intermediate pressure portion of the scroll compressor 1. To be injected. Due to this liquid injection, abnormal rise in the temperature of the refrigerant discharged from the compressor 1 is suppressed.

On the other hand, the second injection circuit 20
A part of the refrigerant liquid flowing through the high-pressure refrigerant liquid line 36 is guided, reduced to a low pressure by the second capillary 22, and the decompressed refrigerant liquid is injected into the accumulator 8 through the refrigerant gas suction line 31. The temperature of the lubricating oil fed into the accumulator 8 via the pipe line 32 decreases due to the cooling action by the liquid injection. The lubricating oil whose temperature has decreased is led to the low-pressure refrigerant gas flowing through the pipe 30 and sent to the compressor 1.

When the compressor 1 is stopped, the solenoid valve 18 is closed. By closing the solenoid valve 18, the injection operations of the two injection circuits 19 and 20 are not performed. In this case, as described above, the refrigerant on the compressor 1 side moves to the accumulator 8 due to the pressure difference between the two injection circuits 19 and 20.

As described above, the solenoid valve 18 is preferably opened while the compressor 1 is operating, but is preferably closed when the temperature of the discharged gas is abnormal as the temperature of the discharged gas decreases.

Note that the second injection circuit 20
It may be connected to an arbitrary point in the refrigerant gas suction line 31 that connects the outlet of the evaporator 5 and the suction side of the compressor 1, but it is preferable to connect to the inflow side of the accumulator 8 that temporarily stores the liquid refrigerant. It is preferable for enhancing the cooling effect of the oil.

In the embodiment shown in FIG. 1, when defrosting by the reverse cycle is performed, immediately after switching from the cooling operation to the defrosting operation when the outside air temperature is high, the high-pressure refrigerant on the condenser 3 side receives the four-way switching valve 2, The air may be sucked into the compressor 1 through the accumulator 8, so that the discharge pressure of the compressor 1 further rises, and a protection device such as a high-pressure switch is activated to stop the operation.

Therefore, when a defrost start signal is issued, the four-way switching valve 2 is switched to the defrost cycle side, and at the same time, the compressor 1 is controlled to be stopped for a predetermined time, for example, 15 seconds, and then started. Thus, the compressor 1
Is stopped, the refrigerant accumulated in the condenser 3 during that time is diffused to the low pressure side and the pressure is reduced, so that it is possible to prevent an abnormal increase in the high pressure when the defrost is started.

[0026]

As described above, according to the present invention, the compressor 1
During operation, both the first injection circuit 19 and the second injection circuit 20 perform the injection operation, so that an abnormal rise in the discharge gas temperature in the compressor 1 is suppressed and the temperature of the lubricating oil returned to the compressor 1 is reduced. It is possible. Also, when the compressor 1 is stopped, even if the solenoid valve 18 is closed, the first and second injection circuits 19 and 20 are connected in series. 2
Thus, the liquid can flow to the suction line side through 0, preventing the liquid compression at the time of starting the compressor 1 thereafter, and achieving a safe operation.

[Brief description of the drawings]

FIG. 1 is a refrigeration circuit diagram in a refrigeration apparatus according to an embodiment of the present invention.

FIG. 2 is a refrigeration circuit diagram in a conventional refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Condenser 4 Expansion mechanism 5 Evaporator 18 Solenoid valve 19 1st injection circuit 20 2nd injection circuit 21 1st capillary 22 2nd capillary 31 Refrigerant gas suction line 36 High pressure refrigerant liquid line

Claims (2)

(57) [Claims] 1. A refrigeration apparatus comprising a compressor 1, a condenser 3, an expansion mechanism 4, and an evaporator 5 to constitute a refrigeration cycle, wherein a high-pressure refrigerant liquid line connected to a refrigerant inflow side of the expansion mechanism 4. 36 refrigerant liquid is introduced, and the pressure is reduced by the first capillary 21,
A first injection circuit 19 for injecting the refrigerant into the intermediate pressure section of the compressor 1, a refrigerant liquid in the high-pressure refrigerant liquid line 36, a pressure reduction in the second capillary 22, and a refrigerant connected to the refrigerant outflow side of the evaporator 5. A second injection circuit 20 for injecting the gas into the gas suction line 31, shared by the first and second injection circuits 19, 20, provided in series with the first capillary 21 and the second capillary 22 on the upstream side, A refrigerating apparatus, comprising: a solenoid valve 18 that is closed when the compressor 1 is stopped. 2. The refrigerating apparatus according to claim 1, wherein said solenoid valve is opened to constantly inject said first and second injection circuits during a refrigerating operation.