JPH043854A - Freezer - Google Patents

Abstract

PURPOSE:To eliminate a lack of oil and improve a reliability in operation by a method wherein a freezer device is provided with a check valve and an oil separator connected in series between a discharging part and a condensor, a differential pressure valve connected between the oil separator and a suction side, and a differential pressure capillary tube. CONSTITUTION:A discharging part 1a of a low pressure type rotary compressor 1 is connected to a condensor 2 through a check valve 5 and an oil separator 6. Oil accumulated at a bottom part of the oil separator 6 is supplied to a differential pressure valve 7 through a pipe 6c. One end of a capirary tube 8 is connected to a differential pressure feeding part 7a of the differential pressure valve 7, and the other end is connected between the compressor 1 and the check valve 5. In the event that a value of reference differential pressure is A, a relation of DELTAP<=A is defined as a normal state and the differential pressure valve 7 is closed and in turn when a relation of DELTAP>=A is attained, the differential pressure valve 7 is opened for a specified period of time, thereby oil accumulated at the oil separator 6 is returned back to a suction pipe acting as a suction side 1b of the compressor 1 and then the oil once reduced in its volume is supplemented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to an improvement in a refrigeration system using a low-pressure rotary compressor.

(Prior Art) A refrigeration system using a conventional low-pressure rotary compressor is as shown in FIG.
Condenser (condenser) 2, capillary tube 3. Evaporators 4 were connected in sequence.

In the refrigeration cycle caused by the operation of the compressor 1, the oil in the oil seal inside the compressor 1 is discharged together with the discharged refrigerant, resulting in a decrease in the oil in the case, which reduces the cooling function and causes wear on the sliding parts. was there.

(Issue 8 to be solved by the invention) In a conventional refrigeration system using a low-pressure rotary compressor, oil is discharged together with the refrigerant when the compressor is operated, and the amount of oil in the case decreases, resulting in a decrease in the cooling function. Measures were requested to prevent this from occurring.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a refrigeration system configured to eliminate the above-mentioned conventional drawbacks and return discharged oil to the compressor with a simple configuration.

[Structure of the invention] (Means for solving problems) This invention is a low pressure rotary compressor.

In a refrigeration system in which a condenser, a capillary tube, and an evaporator are connected in sequence, a check valve and an oil separator are connected in series between the discharge part of the low-pressure rotary compressor and the condenser, and the oil separator. A differential pressure valve is connected between the oil separator and the suction side in order to return the oil separated and stored in the separator to the suction side of the low-pressure rotary compressor, and one end is connected to the differential pressure inlet of the differential pressure valve. and a differential pressure capillary tube whose other end is connected between the discharge part of the low-pressure rotary compressor and the check valve.

(Function) A refrigeration system using a low-pressure rotary compressor according to the present invention includes an oil separator between a check valve and a condenser,
The oil discharged from the compressor along with the refrigerant is separated and stored in this oil separator.

Additionally, since a check valve is provided between the discharge part of the compressor and the oil separator, the differential pressure between the check valve and the compressor that occurs after the compressor is stopped is used to control the opening and closing of the differential pressure valve. The oil accumulated in the oil separator is returned to the suction side of the compressor via the differential pressure valve to replenish the oil shortage.

(Embodiment) Hereinafter, an embodiment of the refrigeration system according to the present invention will be described in detail with reference to FIGS. 1 to 3.

Note that the same components as in FIG. 4 are given the same reference numerals, and detailed explanations are omitted.

That is, FIG. 1 is a block diagram showing one embodiment of the apparatus of the present invention, in which a discharge section 1a of a low-pressure rotary compressor 1 is connected to a condenser 2 via a check valve 5 and an oil separator 6.

The outlet of the condenser 2 is connected to the suction side 1b of the rotary compressor 1 via a capillary tube 3 and an evaporator 4.

The oil separator 6 is in the form of a closed container as shown in FIG. 2, and the high-temperature, high-pressure refrigerant introduced from the upper piping 6a from the check valve 5 side is separated from the oil in the refrigerant while flowing in the direction of arrow Y. and is supplied to the condenser 2 from another pipe 6b also installed at the top. The oil accumulated at the bottom of the oil separator 6 is removed from the pipe 6.
It is supplied to the differential pressure valve 7 via c. It is assumed that the opening directions of the pipes 6a, 6b, and 6c of the oil separator 6 are all provided in the vertical direction as shown in the figure.

The other side of the differential pressure valve 7 connected to the piping 6c of the oil separator 6 is connected to the suction side 1b of the compressor 1, and as the differential pressure valve 7 opens and closes, the oil accumulated in the oil separator B is transferred from the suction side 1b to the compressor 1. It is configured to be collected within 1 hour.

One end of a differential pressure capillary tube 8 is connected to the differential pressure introducing portion 7a of the differential pressure valve 7, and the other end is connected between the compressor 1 and the check valve 5.

The operation of the refrigeration system shown in FIGS. 1 and 2 will be explained with reference to the operating characteristic diagram in FIG. 3.

That is, while the compressor 1 is in operation (ON), the pressure P2 between the compressor 1 and the check valve 5 and the pressure P of the oil separator 6 are lower than the pressure P1 on the suction side 1b of the compressor 1.
3 is as shown in FIG. 2, and the pressures P2 and P3 are approximately at the same level.

However, when the compressor 1 is once stopped (OFF), the high-temperature, high-pressure refrigerant of the compressor 1 flows from the high-pressure part of the cylinder through the oil seal part into the case, which is the low-pressure part, but between the compressor 1 and the check valve 5. The high-temperature, high-pressure refrigerant also flows into the case, and the pressure P2 gradually decreases.

Further, the high-pressure refrigerant on the condenser 2 side from the oil separator 6 also flows through the capillary tube 3 to the low-pressure side evaporator 4, and the pressure P3 similarly decreases.

Note that a check valve 5 is provided between the oil separator 6 and the compressor 1.
is connected, the high-temperature, high-pressure refrigerant on the oil separator 6 side is prevented from flowing to the compressor I side.

Therefore, by reducing the volume between the check valve 5 and the compressor 1, the rate of decrease in the pressure P2 therebetween can be made faster than the rate of decrease in the pressure P3 in the oil separator 6.

Therefore, the inventive device utilizes the difference in pressure drop between P3 and P2, that is, the pressure difference ΔP (=P3 - P2), and uses this pressure difference ΔP as a control signal to open and close (turn on and off) the differential pressure valve 7. ).

For example, if the value of a certain reference differential pressure is A, the differential pressure valve 7 is closed with ΔP≦A in the normal state, and when ΔP≧A is reached, the differential pressure valve 7 is opened for a certain period of time, so that the oil separator The ura accumulated in 6 is transferred to the suction side 1 of compressor 1.
The oil is returned to the suction pipe (b) and operates to replenish the oil that has been reduced.

Therefore, in the refrigeration system of the present invention using a low-pressure rotary compressor, the oil discharged together with the refrigerant can be returned to the low-pressure rotary compressor 1 using the differential pressure. This maintains the transmission function and at the same time prevents wear on the sliding parts to ensure good operation.

[Effects of the Invention] The refrigeration system according to the present invention can eliminate oil shortage with a simple configuration and maintain a reliable and good refrigeration cycle function, and is highly effective in practical use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the refrigeration system according to the present invention, FIG. 2 is a sectional view showing the structure of the oil separator of the system shown in FIG. 1, and FIG. Pressure operating characteristic diagram,
FIG. 4 is a block diagram showing a conventional refrigeration system. 1... Rotary compressor, 2... Condenser, 3...
... Capillary tube, 4... Evaporator, 5...
Check valve, 6... Oil separator, 7... Differential pressure valve, 8...
Differential pressure capillary tube.

Claims (1)

[Claims] In a refrigeration system in which a low-pressure rotary compressor, a condenser, a capillary tube, and an evaporator are connected in sequence, a check valve and an oil separator are sequentially connected in series between a discharge part of the low-pressure rotary compressor and the condenser. and a differential pressure valve connected between the oil separator and the suction side for returning the oil separated and stored in the oil separator to the suction side of the low-pressure rotary compressor, and a differential pressure introduction part of the differential pressure valve. 1. A refrigeration system comprising: a differential pressure capillary tube having one end connected to and the other end connected between the discharge part of the low pressure rotary compressor and the check valve.