JPS62288376A - Refrigerating cycle device - Google Patents

Abstract

PURPOSE:To improve a lubricating property by connecting spaces in the shells of plural compressors to each other with an oil equalizing pipe having an orifice and providing a detector which detects that the lowest oil level is reached and stops the compressor having the higher inside shell pressure, in said compressor. CONSTITUTION:The spaces inside the shells of compressors 1, 2 are connected to each other with an oil equalizing pipe 9 having an orifice 12 in order to balance the quantity of inside oil. On the other hand, an oil level detector 13 is provided on the lowest oil level position H of the compressor 1 having the higher inside shell pressure. As the oil level of the compressor 1 having the higher inside shell pressure is lowered with the operation of the compressor, the operation of the compressor is stopped when the oil level reached the lowest oil level position H. Thereby, oil in the shells of both the compressors 1, 2 is gradually equalized via the oil equalizing pipe 9, eliminating the factors of rise in lubricating oil temp. or insufficient lubrication and enabling operation with a good lubricating property.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a refrigeration cycle device equipped with two compressors for one set of condenser and evaporator. be.

[Conventional technology]

FIG. 2 is a system diagram showing the configuration of this type of conventional refrigeration cycle device. In FIG. 2, a suction pipe 7 of the compressor 1 is connected to a suction pipe 8 of the compressor 2 in a branched manner. The discharge sides of these compressors 1.2 are each connected to a check valve 1.
It is connected to the inlet side of the condenser 30 for liquefying the refrigerant through 0.1 it.

The outlet side of this condenser 3 is via a thermostatic expansion valve 4.

It is connected to the inlet side of an evaporator 50 that vaporizes the refrigerant.

Note that the temperature-sensitive cylinder of the thermostatic expansion valve 4 is provided at the outlet pipe of the evaporator 5.

The outlet pipe of the evaporator 5 is connected to the inlet side of a 7-accumulator 60 for removing liquid particles 11 from the refrigerant gas, and the inlet pipe 7 of the compressor 1 is connected to the outlet side of the accumulator 6.
is connected.

On the other hand, the shell of the compressor 1 and the shell of the compressor 2 are connected to each other by an oil equalizing pipe 9 for equalizing the internal oil amount.

The conventional refrigeration cycle apparatus is constructed as described above, and the high-temperature, high-pressure refrigerant discharged from the compressors 1 and 2 passes through the check valves 10 and 11, respectively. It is fed to the condenser 3 where it is liquefied.

Next, the liquefied refrigerant is depressurized by the thermostatic expansion valve 4, and then vaporized again by the evaporator 5.

Sarani, pass through the accumulator 6t and return to the compressor 1゜2.
is inhaled. In this way, a refrigeration cycle with multiple compressors is formed.

By the way, the suction pipe 8 of this refrigeration cycle is connected so that its tip protrudes into the inside of the suction f7, so that refrigerant and oil are sucked into the compressor 1, but only refrigerant is sucked into the compressor 2. only inhaled.

The pipe diameters of some of the suction pipes 7 and 8 are selected so that the shell internal pressure P of the compressor 2 is lower than the shell internal pressure P of the compressor 1 .

A part of the oil sucked into the compressor 11C is sent to the compressor 2 through the oil equalizing pipe 9t, but between the shell internal pressure P1 of the compressor 1 and the shell internal pressure P of the compressor 2. p,>p,
Because of this relationship, the oil level of the compressor 1 is approximately equal to the position of the oil equalizing pipe 7, and the oil level of the compressor 2 is operated in a state that is considerably higher than the position of the oil equalizing pipe 7.

This is not limited to when two compressors are operated simultaneously; for example, if one is operated and the other is stopped, the pressure inside the shell of the stopped compressor will be the same as that of the operating compressor. The oil level of the compressor when it is stopped is approximately equal to the position of the oil equalizing pipe 7, and the oil level of the operating compressor is considerably higher than the position of the oil equalizing pipe 7.

[Problem that the invention seeks to solve]

In conventional refrigeration cycle equipment as described above, there is a large difference in the oil amount between the compressors, and if the absolute amount is excessive, the oil temperature will rise excessively due to increased oil rise and heating by the discharge muffler. On the other hand, when the amount of oil is too low, there are problems such as poor lubrication.

This invention was made to solve this problem, and it is possible to suppress the difference in oil amount between compressors to a significantly low level, thereby preventing an excessive rise in oil temperature, poor lubrication, and an increase in oil level. The purpose of this invention is to obtain a highly reliable refrigeration cycle device that can prevent this.

[The tth way to solve the problem]

The refrigerating tickle device according to the present invention is provided with an oil level detector at the lowest oil level portion of the compressor having a higher shell pressure.

[Effect]

In this invention, the amount of oil in the high-pressure compressor is transferred to the low-pressure compressor during long-term operation.

The oil level detector detects when the lowest oil level of the compressor with higher shell pressure has reached the lowest oil level.

Stop both compressors and balance them using the oil equalizing pipe to equalize the oil amount.

〔Example〕

Embodiments of the refrigeration cycle apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of one embodiment. In this Figure 1, parts that are the same as those in Figure 2 are given the same reference numerals and their explanations are omitted in order to avoid redundant explanation, and we will mainly describe the parts that are different from Figure 2. .

1 differs from FIG. 2 in that an orifice 12t is provided in the oil equalizing pipe 9, and an oil level detector 13t is provided at the lowest oil level position H on the compressor 1 side where the pressure PI is high. This oil level detector 13 is fixed to the lower part of the oil equalizing pipe 9.

Next, the operation of the present invention configured as described above will be explained. If compressors 1 and 2 are operated simultaneously,
As mentioned above, all of the oil returned from the accumulator 7 is sucked into the compressor 1, and a portion of the oil returns from the compressor 1 due to the pressure inside the shell of the compressor 1.
In case 1, the pressure inside the shell of compressor 2 is also high.

Therefore, the oil sucked into the compressor 1 is supplied to the compressor 21C through the oil equalizing pipe 9, and the supply of oil can be controlled by the orifice 12 provided in the oil equalizing pipe 9. In comparison, the amount of oil in compressor 1 increases and the amount of oil in compressor 2 decreases, which significantly reduces the difference in oil amount.

Next, operate either part of compressor 1 or compressor 2,
When the other one is stopped, the pressure inside the shell of the stopped compressor becomes higher than the same pressure in the shell of the compressor in operation,
As a result, oil is supplied from the stopped compressor to the operating compressor, but the amount of oil supplied is controlled by the orifice 12 installed in the oil equalizing pipe 9, and as a result, compared to conventional equipment, oil is supplied to the operating compressor. The amount of oil in the compressor increases, and the amount of oil in the compressor during operation decreases.

As operation continues, the oil level in the high-pressure compressor 1 moves and drops to the lowest oil level H.

The oil level detector 13 is activated, and compressor 1 and compressor 2 are stopped.

As a result, the oil equalizing pipe 9 and orifice 12 are completely passed through,
The oil amounts in compressor 1 and compressor 2 can be quickly equalized.

Normally, it takes several minutes or more from stopping the compressors 1 and 2 to starting them, so the orifice 12 is selected so that the time required to equalize the compressors is 1 to 3 minutes.

In the above embodiment, a refrigeration cycle apparatus equipped with two compressors has been described, but the present invention can also be applied to a refrigeration cycle in which the internal oil amount of a plurality of compressors is equalized.

〔Effect of the invention〕

As explained above, this invention is equipped with an oil level detector at the lowest oil level position in the equalized oil pipe provided at the orifice and in the lower part of the compressor where the pressure inside the shell is higher. The difference in oil amount between compressors can be kept extremely low.

Accordingly, it is possible to prevent an excessive rise in oil temperature, poor a-sliding, and an increase in oil drainage, which in turn has the effect of significantly improving reliability.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the configuration of an embodiment of the refrigeration cycle device of the present invention, and FIG. 2 is a system diagram showing the configuration of a conventional refrigeration cycle device. 1.2... Compressor, 3... Condenser, 4... Temperature type expansion valve, 5... Evaporator, 6... Accumulator, 7
, 8... Suction pipe, 9... Oil equalizing pipe, 12... Orifice, 13... Oil level detector. Note that the same reference numerals in the figures indicate corresponding parts.

Claims (1)

[Claims] A plurality of compressors forming a refrigeration cycle together with a set of condensers and evaporators, oil equalizing pipes interconnecting the compressors to equalize the amount of oil in the shells of these compressors; The orifice is installed in the oil equalizing pipe and controls the amount of oil supplied from the compressor with higher shell internal pressure to the compressor with lower shell internal pressure. A refrigeration cycle device comprising: an oil level detector that stops the plurality of compressors for a predetermined period of time when a surface portion is detected.