JPH06337171A - Refrigerating device - Google Patents

Abstract

PURPOSE:To eliminate refrigerant, returning to the suction side of a compressor from an oil separater after bypassing while keeping a high temperature, so that a motor for the compressor is cooled sufficiently and the circulating amount of oil of a refrigerant circuit is reduced, in a refrigerating device. CONSTITUTION:In a refrigerating device, having a refrigerant circuit, connecting a compressor 1, an oil separater 2, a condenser 3, a choke valve 4 and an evaporator 5, a radiator 3a is provided in an oil returning circuit 10, branched from the oil separater 2 and connected to the suction side of the compressor 1, to cool oil in the oil returning circuit 10, then, the oil is introduced into a heat exchanger 7 through a choke valve 6 to effect heat exchange between refrigerant, running between the condenser 3 of the refrigerant circuit and the choke valve 4, to cool it, then, the oil is returned to the suction side of the compressor 1. On the other hand, a heat exchanger is provided in a liquid injection circuit, which conducts refrigerant for cooling from the outlet side of a condenser to the compressor, to cool the refrigerant for cooling the compressor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus used in a condensing unit or the like used in a refrigerating / freezing showcase.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a refrigerating apparatus having a conventional oil separator. The refrigerant leaving the compressor 1 such as a scroll compressor having a low-pressure housing enters the oil separator 2 to separate the oil, enters the condenser 3, radiates heat to condense liquid, and is decompressed in the throttle 4. In addition, it reaches the evaporator 5, where it takes heat from the surroundings to evaporate and vaporize, and then returns to the compressor 1.
The oil separated by the oil separator 2 enters the oil return circuit, is returned to the suction side of the refrigerant circuit by the throttle 6a in an appropriate amount, and is used for lubrication in the compressor 1.

FIG. 4 shows another example of a conventional refrigeration system having an oil separator. The refrigerant leaving the compressor 1 such as a scroll compressor having a low-pressure housing enters the oil separator 2 to separate the oil, enters the condenser 3, radiates heat to condense liquid, and is decompressed in the throttle 4. It reaches the upper evaporator 5, where heat is taken from the surroundings to evaporate and vaporize, and the compressor 1
Return to. A part of the refrigerant discharged from the condenser 3 passes through the liquid injection circuit 11 branched from the refrigerant circuit between the condenser 3 and the throttle 4, and an appropriate amount returns to the compressor 1 by the throttle 8 to be used for cooling the compressor. To be done. The oil separated by the oil separator 2 enters the oil return circuit, is returned to the suction side of the refrigerant circuit by an appropriate amount by the throttle 6a, and is used for lubrication in the compressor 1.

[0004]

In the conventional refrigeration system described above, the return amount (throttle amount) of oil is determined on the basis of the maximum amount of oil circulation, so that part of the refrigerant together with the oil is part of the oil separator. Bypassing the refrigerant circuit more than necessary, the amount of refrigerant circulation that can be effectively used in the evaporator is reduced.

Particularly, in the case of a condensing unit,
Since the evaporation pressure range to be used is wide, when used in a region where the refrigerant circulation amount is small, such as a low pressure region, the bypass refrigerant amount becomes relatively larger than the refrigerant amount flowing in the refrigerant circuit. Therefore, the loss of ability cannot be ignored.

Further, as a result of increasing the temperature of the gas sucked into the compressor by the bypass refrigerant, the cooling of the compression motor provided in the low-pressure housing of the compressor becomes insufficient, and the temperature of the gas discharged from the compressor becomes high. Then, there is a disadvantage that the high temperature operation is continued.

Further, in a refrigerating apparatus using a compressor having a high-pressure housing and a liquid injection circuit, the above problem can be solved by a refrigerant circuit disclosed in, for example, Japanese Patent Laid-Open No. 2-85649, but a low-pressure housing. In the compressor having, the oil holding portion becomes the low pressure portion, and therefore even if the injection circuit is provided, the oil only circulates on the high pressure side, and therefore this cannot be used.

The present invention is intended to provide a refrigerating apparatus which can solve the above problems.

[0009]

The refrigerating apparatus of the present invention takes the following means.

(1) In a refrigerating apparatus having a refrigerant circuit in which a compressor, an oil separator, a condenser, a throttle, and an evaporator are connected by a refrigerant pipe, branching from the oil separator and passing through a radiator and a throttle. And an oil return circuit connected to the suction side of the compressor via a heat exchanger for exchanging heat with the refrigerant between the condenser and the throttle of the refrigerant circuit.

(2) A refrigerant circuit in which a compressor, an oil separator, a condenser, a throttle and an evaporator are connected by a refrigerant pipe, and a liquid injection for returning a part of the refrigerant discharged from the condenser to the compressor. In a refrigeration apparatus having a circuit, oil that branches from the oil separator and is connected to the suction side of the compressor via a heat exchanger that exchanges heat with the refrigerant that has exited the condenser of the refrigerant circuit via a radiator and a throttle. A feature is that a return circuit is provided.

(3) In the refrigerating apparatus of (2), the heat exchanger is provided in the liquid injection circuit.

[0013]

Since the refrigerating apparatus of the present invention is constructed as described above, the refrigerant flowing into the oil return circuit enters the radiator together with the oil separated by the oil separator, and radiates heat there to condense and liquefy. To do. This refrigerant containing a large amount of oil is decompressed by the throttle and reaches the heat exchanger, where it exchanges heat with the refrigerant exiting the condenser of the refrigerant circuit and cools it, thereby evaporating and vaporizing itself. Return to the suction side of the compressor.

For this reason, there is no refrigerant that bypasses the oil return circuit and remains at a high temperature after passing through the oil separator, so that the compressor motor can be cooled sufficiently, and the discharge gas temperature of the compressor can be controlled. It will not be significantly raised. Further, the refrigerant bypassing through the oil return circuit exchanges heat with the refrigerant that has discharged from the condenser after heat dissipation or has exited the condenser and has entered the injection circuit, so there is no loss of capacity. Further, since the oil is separated by the oil separator and returned to the compressor via the oil return circuit, the amount of oil circulation in the refrigerant circuit passing through the evaporator is reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. This embodiment is an improvement of the conventional refrigeration system shown in FIG. 3. In FIG. 1, the same members as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the refrigerant discharged from the compressor 1 having the low pressure housing returns to the compressor 1 through the oil separator 2, the condenser 3, the throttle 4, and the evaporator 5 provided in the refrigerant circuit. This is the same as the conventional refrigeration system shown in FIG. The oil separator 2 includes a radiator 3a, a throttle 6, and a heat exchanger 7 for exchanging heat with the refrigerant in the refrigerant circuit between the condenser 3 and the throttle 4.
Is connected, and the oil return circuit 10 is connected to the suction side of the compressor.

In this embodiment, the oil-containing refrigerant separated by the oil separator 2 enters the oil return circuit 10 and radiates heat in the radiator 3a to be condensed and liquefied, and the heat exchanger 7 is divided into appropriate amounts by the throttle 6.
To remove the heat from the liquid refrigerant in the refrigerant circuit that has flowed out of the condenser 3 to evaporate and vaporize itself and return to the suction side of the compressor 1.

In the present embodiment, as described above, the oil return circuit 1
Since the radiator 3a and the heat exchanger 7 are provided at 0, the refrigerant will not bypass the oil return circuit 10 at a high temperature. Further, the refrigerant containing oil in the oil return circuit 10 exchanges heat with the refrigerant in the refrigerant circuit that reaches the evaporator 5 via the throttle 4 in the heat exchanger 7, and therefore, when it joins on the suction side of the compressor 1, the refrigerant circuit The temperature level can be matched with that of the refrigerant, and thermal loss can be eliminated. Further, this makes it possible to increase the amount of the refrigerant flowing through the oil return circuit 10, and reduce the amount of the refrigerant flowing through the refrigerant circuit without lowering the capacity, reducing the pipe size of the refrigerant circuit and reducing the pipe pressure loss. Is possible.

Furthermore, the oil is separated in the oil separator 2,
Since the suction side of the compressor 1 returns to the compressor via the oil return circuit 10, the amount of oil circulation in the refrigerant circuit including the evaporator 5 can be reduced.

A second embodiment of the present invention will be described with reference to FIG. This embodiment is an improvement of the refrigerating apparatus shown in FIG. 4. In FIG. 2, the same members as those in FIG. 4 are designated by the same numerals, and the description thereof will be omitted.

In this embodiment, the refrigerant discharged from the compressor 1 having the low pressure housing returns to the compressor 1 through the oil separator 2, the condenser 3, the throttle 4, and the evaporator 5 provided in the refrigerant circuit. This is the same as the conventional refrigeration system shown in FIG. Further, a part of the refrigerant discharged from the condenser 3 passes through the liquid injection circuit 11, returns to the compressor 1 in an appropriate amount by the throttle 8, and is used for cooling the compressor. It is the same as the refrigerator.

The oil separator 2 includes a radiator 3a and a throttle 6
And an oil return circuit 10 provided with a heat exchanger 7 for exchanging heat with the refrigerant between the condenser 3 and the throttle 8 in the liquid injection circuit 11, and the oil return circuit 10 is compressed. It is connected to the suction side of the machine.

In this embodiment, the oil-containing refrigerant separated in the oil separator 2 enters the oil return circuit 10 and radiates heat in the radiator 3a to be condensed and liquefied.
To the liquid injection circuit 11
By taking heat from the liquid refrigerant that has entered, it evaporates and vaporizes itself and returns to the suction side of the compressor 1.

In the present embodiment, as described above, the oil return circuit 1
Since the radiator 3a and the heat exchanger 7 are provided at 0, the refrigerant will not bypass the oil return circuit 10 at a high temperature. Further, the oil-containing refrigerant of the oil return circuit 10 returns to the compressor 1 via the throttle 8 of the liquid injection circuit 11 in the heat exchanger 7 and exchanges heat with the refrigerant used for cooling the compressor 1. When merging on the suction side, the temperature level can be matched with that of the refrigerant in the refrigerant circuit, and thermal loss can be eliminated.

Further, in the heat exchanger 7, since the refrigerant flowing through the liquid injection circuit 11 is cooled, it becomes possible to reduce the amount of refrigerant required for cooling the compressor 1 and to have sufficient cooling performance. The refrigerant discharged from the compressor 1 can be reduced as it is, and the required power of the compressor 1 can be reduced.

Further, the oil is separated by the oil separator 2,
Since the suction side of the compressor 1 returns to the compressor via the oil return circuit 10, the amount of oil circulation in the refrigerant circuit including the evaporator 5 can be reduced.

[0027]

According to the present invention as set forth in claim 1, the refrigerant in the refrigerant circuit that has flowed out of the condenser and the heat in the oil return circuit that is branched from the oil separator and has a large amount of oil that has passed through the radiator and the throttle and heat. By performing the replacement, the refrigerant is prevented from bypassing the high temperature through the oil return circuit and returning to the compressor. As a result, it is possible to sufficiently cool the compression motor, and it is possible to eliminate the inconvenience that the discharge gas temperature of the compressor becomes high and the high temperature operation is continued.

Further, the refrigerant flowing through the oil return circuit is decompressed by the throttle after heat dissipation in the radiator and exchanges heat with the refrigerant in the refrigerant circuit. You can adjust the level and you will not lose the ability. Furthermore, this makes it possible to increase the amount of refrigerant flowing in the oil return circuit, and it is possible to reduce the amount of refrigerant flowing in the refrigerant circuit without lowering the capacity, and it is possible to reduce the piping size of the refrigerant circuit and the piping pressure loss. Will also be.

Furthermore, since the oil is separated by the oil separator and returned to the compressor through the oil return circuit, the amount of oil circulation in the refrigerant circuit including the evaporator can be reduced.

In the present invention as set forth in claims 2 and 3, the refrigerant in the refrigerant circuit that has flowed out of the condenser and the heat in the oil return circuit that is branched from the oil separator and passes through the radiator and throttle and contains a large amount of oil By performing the replacement, the refrigerant is prevented from bypassing the high temperature through the oil return circuit and returning to the compressor. As a result, it is possible to sufficiently cool the compression motor, and it is possible to eliminate the inconvenience that the discharge gas temperature of the compressor becomes high and the high temperature operation is continued.

Further, the refrigerant flowing through the oil return circuit is reduced in pressure after being radiated by the radiator and then is decompressed and exchanges heat with the refrigerant exiting the condenser or the refrigerant in the liquid injection circuit. At the time of merging, the temperature level of the refrigerant in the refrigerant circuit can be matched, and there is no loss of capacity. Further, by this, the refrigerant flowing through the liquid injection circuit is cooled, so that the amount of refrigerant necessary for cooling the compressor can be reduced, and the refrigerant discharged from the compressor with sufficient cooling performance can be reduced. Therefore, the power required for the compressor can be reduced.

Furthermore, since the oil is separated by the oil separator and returned to the compressor through the oil return circuit, the oil circulation amount in the refrigerant circuit including the evaporator can be reduced.

[Brief description of drawings]

FIG. 1 is a system diagram of a refrigerating apparatus according to a first embodiment of the present invention.

FIG. 2 is a system diagram of a refrigerating apparatus according to a second embodiment of the present invention.

FIG. 3 is a system diagram of an example of a conventional refrigeration system.

FIG. 4 is a system diagram of another example of a conventional refrigeration system.

[Explanation of symbols]

 1 Compressor 2 Oil Separator 3 Condenser 3a Radiator 4 Throttle 5 Evaporator 6 Throttle 7 Heat Exchanger 8 Throttle 10 Oil Return Circuit 11 Liquid Injection Circuit

Claims (3)

[Claims] 1. A refrigerating apparatus having a refrigerant circuit in which a compressor, an oil separator, a condenser, a throttle, and an evaporator are connected by a refrigerant pipe, and branches from the oil separator, and a radiator and a throttle are provided. A refrigeration system comprising an oil return circuit connected to the suction side of the compressor via a heat exchanger that exchanges heat with the refrigerant between the condenser and the throttle of the refrigerant circuit. 2. A refrigerant circuit in which a compressor, an oil separator, a condenser, a throttle and an evaporator are connected by a refrigerant pipe, and a liquid injection circuit for returning a part of the refrigerant discharged from the condenser to the compressor. In the refrigerating apparatus having the above, the oil return that is connected to the suction side of the compressor via the heat exchanger that branches from the oil separator and exchanges heat with the refrigerant that has exited the condenser of the refrigerant circuit via the radiator and the throttle. A refrigerating apparatus having a circuit. 3. The refrigerating apparatus according to claim 2, wherein the heat exchanger is provided in a liquid injection circuit.