JPH0814430B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a refrigerating apparatus applied to a condensing unit or the like used in a refrigerating / freezing syrup case.

[Conventional technology]

In a conventional refrigeration system that cools a built-in drive motor of a compressor by liquid injection, for example,
As shown in the diagram system diagram, the refrigerant discharged from the rotary compressor 20 enters the oil separator 21 to separate the oil, enters the condenser 22, and radiates heat to condense and liquefy, and part of the liquefied refrigerant is carried by the carrier. Although it divides into the parallel tube 25, most of it is decompressed in the throttle 23 and reaches the evaporator 24, which takes heat from the surroundings, evaporates and vaporizes, and passes through the accumulator 25 and the compressor.
Return to 20.

In the compressor 20, the gas refrigerant returned from the evaporator 24 is directly guided to the cylinder and compressed, and during the compression process, the refrigerant gas decompressed and introduced by the capillary tube 25 causes the refrigerant gas in the middle of compression. It is cooled, becomes a gas with less superheat, and is subsequently compressed.

As a result, the refrigerant discharged from the cylinder after completion of compression does not become so high in temperature that the temperature is sufficient to cool the compressor driving motor built in the case of the compressor 20. By cooling the
The high-temperature, high-pressure gas refrigerant is discharged from the compressor 20 to complete 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 by an appropriate amount by the throttle 26 to be used for lubrication in the compressor 20.

[Problems to be Solved by the Invention]

In the above conventional refrigeration system, the amount of oil returned (throttle amount) is
Since the maximum amount of oil circulation is determined as a standard, part of the refrigerant flows with the oil, bypassing the refrigerant circuit more than necessary from the oil separator, and the effective circulation amount of refrigerant in the evaporator decreases. Become.

In particular, in the case of the 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 in the low pressure region, the bypass refrigerant amount is relative to the refrigerant amount flowing in the refrigerant circuit. Increase. 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 refrigerant gas in the middle of compression is not sufficiently cooled even though liquid injection is performed.

The present invention is intended to solve the above problems of the conventional refrigeration system.

[Means for solving the problem]

The present invention, a compressor, an oil separator, a condenser, a throttle, a refrigerant circuit formed by connecting an evaporator with a refrigerant pipe and a throttle for adjusting the flow rate of a part of the refrigerant exiting the condenser. A refrigeration apparatus having a liquid injection circuit for returning to the compressor, wherein the refrigeration apparatus is provided with an oil return circuit branched from the oil separator and connected to a downstream side of the throttle of the liquid injection circuit via a radiator and a throttle. Is.

[Action]

Since the refrigerating apparatus of the present invention is configured as described above, the refrigerant separated by the oil separator and flowing into the oil return circuit passes through the suction side of the refrigerant circuit after being cooled together with the oil separated by the oil separator. Instead, it returns directly to the compressor.

For this reason, the amount of refrigerant bypassed via 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, and a predetermined amount of refrigerant flows in the refrigerant circuit, so that the capacity corresponding to the evaporation pressure can be obtained. Further, since the oil is separated by the oil separator and returns to the compressor via the oil return circuit and the liquid injection circuit, the oil circulation amount in the refrigerant circuit passing through the evaporator is reduced.

〔Example〕

FIG. 1 shows an embodiment of the present invention. The same members in the conventional refrigeration system are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the refrigerant discharged from the compressor 20 returns to the compressor 20 via the oil separator 21, the condenser 22, the throttle 23, the evaporator 24, and the accumulator 25.
It is similar to a conventional refrigeration system. Above oil separator 21
Is connected to an oil return circuit 1 provided with a radiator 2 and a throttle 3, and is provided with a throttle 5 branching from a refrigerant circuit in the middle of the condenser 22 and the throttle 23, and a liquid injection circuit reaching the compressor 20. The oil return circuit 1 is connected to the downstream side of the throttle 5 of 4.

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 a part of the heat by the radiator 2, and flows into the liquid injection circuit 4 by the throttle 3 in an appropriate amount, From the circuit, it joins the refrigerant through the diversion throttle 5, and is returned to the middle of the compression process of the compressor 20.

In the present embodiment, as described above, the oil return circuit 1 is connected to the liquid injection circuit 4, so that the amount of refrigerant bypassing the oil return circuit 1 to the suction side can be eliminated, and the suction pressure changes. However, since there is no influence from the oil return circuit that bypasses the refrigerant circuit, a required amount of refrigerant flows through the refrigerant circuit, whereby the capacity commensurate with the evaporation pressure is obtained.

Further, since the oil is separated by the oil separator 21 and returns to the compressor via the oil return circuit 1 and the liquid injection circuit 4, it is possible to reduce the amount of oil circulation in the refrigerant circuit including the evaporator. Further, the oil return circuit 1 includes a radiator 2
Is provided, the overheated refrigerant or oil will not flow into the liquid injection circuit 4, and the cooling action of the compressor 20 will not be inconvenient. Further, since the oil return circuit 1 is provided with the throttle 3, an excessive amount of refrigerant does not flow into the liquid injection circuit 4 through the oil return circuit 1 and a proper flow rate can be obtained. Necessary and sufficient cooling of the compressor can be performed.

〔The invention's effect〕

The present invention is a liquid injection circuit for returning a part of the refrigerant discharged from the condenser to the compressor, and by connecting an oil return circuit having a radiator and a throttle branched from the oil separator, through the oil return circuit. The amount of the refrigerant bypassed to the suction side can be eliminated, and even if the suction pressure changes, a required amount of the refrigerant flows in the refrigerant circuit, and the capacity corresponding to the evaporation pressure can be obtained.

Further, since the oil is separated by the oil separator and returns to the compressor via the oil return circuit and the liquid injection circuit, the oil circulation amount in the refrigerant circuit including the evaporator can be reduced. Moreover, the oil and the refrigerant separated by the oil separator are cooled by the radiator and then flow into the liquid injection circuit in an appropriate amount by being throttled by the throttle, so that the refrigerant of the same liquid injection circuit is inserted through another throttle. Of the compressor and the cooling effect of the compressor is not impaired.

[Brief description of drawings]

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. 1 ... Oil return circuit, 2 ... Radiator, 3 ... Aperture, 4 ...
Liquid injection circuit, 5 ... throttle, 20 ... compressor,
21 …… Oil separator, 22 …… Condenser, 23 …… Squeezer,
24 …… Evaporator, 25 …… Aki Yumulator.

Claims (1)

[Claims] 1. 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 throttle for adjusting a flow rate of a part of the refrigerant discharged from the condenser. In a refrigerating apparatus having a liquid injection circuit for returning to the compressor, an oil return circuit is provided which branches from the oil separator and is connected downstream of the throttle of the liquid injection circuit via a radiator and a throttle. Refrigeration equipment.