JPH0285649A - Refrigerator - Google Patents

Abstract

PURPOSE:To make it possible to obtain a capacity equivalent to a vaporization pressure even when a suction pressure may be subject to change by installing an oil return circuit which is branched from an oil separator and is communicated with a solution injection circuit by way of a radiator and a throttle. CONSTITUTION:The oil separated at an oil separator 21 enters an oil return circuit 1 with a part of refrigerant, discharges partially heat at a radiator 2, enters a liquid injection circuit 4 by a throttle 3 in an appropriate amount, gets divided from a refrigeration circuit, joins with the refrigerant which has passed through a throttle 5, and get returned on the way to a compression process of a compressor 20. Therefore, this construction reduces the quantity of refrigerant which bypasses by way of the oil return circuit 1 and allows a specified quantity of refrigerant to flow through the refrigerant circuit since said refrigerant circuit is not affected by the oil return circuit which bypasses the refrigerant even if the suction pressure is subject to changes so that a specified quantity of refrigerant may flow in said refrigerant circuit, thereby providing a proper capacity equivalent to the vaporization pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a refrigeration system applied to a condensing unit or the like used in a refrigerated/frozen showcase.

[Conventional technology]

In a conventional refrigeration system that uses liquid injection to cool the built-in drive motor of a compressor, for example, as shown in the system diagram in Figure 2, the refrigerant that exits the rotary compressor 20 enters the oil separator 21. Separated and condenser 2
2, where it radiates heat and condenses and liquefies. A part of the liquefied refrigerant is diverted to the capillary tube 25, but most of it is depressurized at the throttle 23 and reaches the evaporator 24, where it removes heat from the surroundings. Take away, evaporate, vaporize and accumulator 25
and then returns to the compressor 20.

In the compressor 20, the gas refrigerant returned from the evaporator 24 is directly introduced into the cylinder and compressed. During the compression process, the refrigerant gas is decompressed and introduced through the capillary tube 25, and the refrigerant gas is cooled during compression. The gas becomes less superheated and continues to be compressed.

As a result, the refrigerant that has finished compression and is discharged from the cylinder does not reach a very high temperature, but is at a temperature sufficient to cool the compressor drive motor built into the compressor 200 case. By cooling it, it heats itself,
It becomes a high-temperature, high-pressure gas refrigerant and is discharged from the compressor 20, completing the refrigeration cycle.

On the other hand, the oil separated by the oil separator 21 enters the oil return circuit and is returned to the suction side of the refrigerant circuit in appropriate amounts by the throttle 26 to provide lubrication within the compressor 20.

[Problem to be solved by the invention]

In the above-mentioned conventional refrigeration system, the oil return t (restriction amount) is determined based on the maximum amount of oil circulation, and a portion of the refrigerant along with the oil is bypassed through the refrigerant circuit by the oil separator. This results in a reduction in the amount of refrigerant circulation that can be effectively utilized in the evaporator.

In particular, in the case of condensing units, the evaporation pressure range used is wide, so when used in areas where the amount of refrigerant circulation is small, such as a low pressure area, the amount of bypass refrigerant is relative to the amount of refrigerant flowing into the refrigerant circuit. It becomes more common. Therefore, the loss of ability cannot be ignored.

Furthermore, as a result of increasing the temperature of the gas sucked into the compressor by the bypass refrigerant, the refrigerant gas during compression is not sufficiently cooled despite liquid injection.

The present invention aims to solve the above-mentioned problems of conventional refrigeration equipment.

[Means to solve the problem]

The present invention includes a compressor, an oil separator, a condenser, a diaphragm,
In a refrigeration system having a refrigerant circuit in which an evaporator is connected to a refrigerant pipe, and a liquid injection circuit that returns a part of the refrigerant exiting the condenser to the Okagi compressor, the refrigeration system has a radiator and a diaphragm branched from the oil separator. An oil return circuit was provided which was connected to the liquid injection circuit via the oil injection circuit.

[Effect]

Since the refrigeration system of the present invention is configured as described above, the refrigerant separated by the oil separator and flowing into the oil return circuit is
Together with the oil separated by the oil separator, the oil returns directly to the compressor without passing through the suction side of the refrigerant circuit.

For this reason, the amount of refrigerant bypassed through the oil return circuit is reduced. On the other hand, even if the suction pressure changes, the refrigerant circuit is not affected by the oil return circuit, a predetermined amount of refrigerant flows through the refrigerant circuit, and a capacity commensurate with the evaporation pressure is obtained. Furthermore, since the oil is separated by the oil separator and returned to the compressor via the oil return circuit and the liquid injection circuit, the amount of oil circulating in the refrigerant circuit passing through the evaporator is reduced.

〔Example〕

FIG. 1 shows an embodiment of the present invention. Identical members in the conventional refrigeration system are numbered the same, and their explanations will be omitted.

In this embodiment, the refrigerant leaving the compressor 20 returns to the compressor 20 through an oil separator 21, a condenser 22, a throttle 23, an evaporator 24, and an aginemulator 25, which is different from the conventional refrigeration system. The same is true. , an oil return circuit 1 provided with a radiator 2 and a throttle 3 is connected to the oil separator 21, and a condenser 22 and a throttle 2 are connected to the oil return circuit 1.
The liquid injection circuit 4 is branched from the refrigerant circuit in the middle of 3 and is provided with a throttle 5, and also extends to the compressor 20.
The oil return circuit 1 is connected to the downstream side of the oil return circuit 1 .

In this embodiment, the oil separated by the oil separator 21 enters the oil return circuit 1 together with a part of the refrigerant, radiates part of the heat by the radiator 2, and flows into the liquid injection circuit 4 in appropriate amounts by the throttle 3, where the refrigerant It joins with the refrigerant that has passed through the shunting throttle 5 from the circuit and is returned to the compressor 20 during its compression process.

In this embodiment, since the oil return circuit 1 is connected to the liquid injection circuit 4 as described above, the amount of refrigerant bypassed through the oil return circuit 1 can be reduced, and the suction pressure can be changed. However, since the refrigerant circuit is not affected by the bypass oil return circuit, the refrigerant of the required element flows through the refrigerant circuit, thereby providing a capacity commensurate with the evaporation pressure.

Further, since the oil is separated by the oil separator 21 and returned to the compressor via the oil return filter 1 and the liquid injection circuit 4, it is possible to reduce the amount of oil circulated in the refrigerant circuit including the evaporator.

〔Effect of the invention〕

In the present invention, an oil return circuit branched from an oil separator and having a radiator and a throttle is connected to a liquid injection circuit that returns part of the refrigerant that has exited the condenser to the compressor, thereby bypassing the refrigerant through the oil return circuit. Not only can the amount of refrigerant be reduced, but also the required amount of refrigerant can flow through the refrigerant circuit even if the suction pressure changes, and a capacity commensurate with the evaporation pressure can be obtained.

Furthermore, since the oil is separated by the oil separator and returned to the compressor via the oil return circuit and the liquid injection circuit, it is possible to reduce the amount of oil circulating in the refrigerant circuit including the evaporator.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention, and FIG. 2 is a system diagram of a conventional refrigeration system. l... Oil return circuit, 2... Heat sink, 3... Throttle, 4... Liquid injection circuit, 5... Throttle, 20... Compressor, 21... Oil separator, 22 ...Condenser, 23...Aperture, 24...
・Evaporator, 25...Accumulator.

Claims (1)

[Claims] In the refrigeration system having a refrigerant circuit in which a compressor, an oil separator, a condenser, a throttle, and an evaporator are connected by refrigerant piping, and a liquid injection circuit for returning a part of the refrigerant that has exited the condenser to the compressor, A refrigeration system comprising an oil return circuit branching from an oil separator and connected to the liquid injection circuit via a radiator and a throttle.