JPH10267435A - Freezing cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a refrigerant equalizing pipe and concurrently prevent a refrigerant surface stored at bottom sections of housings 1a, 2a of each of compressors from being lowered than a minimum requisite refrigerant surface position in a freezing cycle in which one accumulator is installed at suction sides of a plurality of low pressure housing type compressors connected in parallel with a refrigerant circuit. SOLUTION: There are provided oil return holes 43, 44 opened into refrigerant 45 stored at a bottom part in a casing 47 of an accumulator 40. The other ends of a plurality of outlet pipes 41, 42 with their opposite ends being opened above refrigerant surface 46 of the refrigerant 45 are connected to housings 1a, 2a of each of the compressors 1, 2 through each of suction pipes 5, 6. Then, the other ends are opened at minimum requisite refrigerant surface positions 23, 24 of refrigerants 21, 22 stored in it and each of the suction pipes 5, 6 is mounted at a lower position than the minimum requisite refrigerant surface positions 23, 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigeration cycle for an air conditioner or the like.

[0002]

2. Description of the Related Art An example of a conventional refrigeration cycle is shown in FIG. In FIG. 3, reference numerals 1 and 2 denote low-pressure housing type compressors which are connected in parallel to a refrigerant circuit, and one accumulator 3 is installed on the suction side of each of the compressors 1 and 2.

During the cooling operation, the gas refrigerant discharged from the compressors 1 and 2 enters the merging pipe 9 through the discharge pipes 7 and 8 as shown by solid arrows, and merges there, and then passes through the four-way valve 36. The heat enters the outdoor heat exchanger 37, where it is condensed and liquefied by radiating heat to the outside air. This liquid refrigerant is adiabatically expanded by being throttled by the throttle mechanism 38, and then enters the indoor heat exchanger 39,
Here, the indoor air is cooled and evaporated.

[0004] The gas refrigerant flows into the casing 30 of the accumulator 3 through the four-way valve 36 from the suction pipe 31, where mist such as liquid refrigerant and lubricating oil contained in the gas refrigerant is separated. The gas refrigerant from which the mist has been separated flows into the U-shaped pipe 32 through its upper end opening, flows out through the U-shaped pipe 32, branches off, passes through the suction pipes 5, 6, and the housings of the compressors 1 and 2. Inhaled into 1a, 2a.

[0005] The mist of the liquid refrigerant, lubricating oil and the like separated in the casing 30 of the accumulator 3 falls to the casing.
It is temporarily stored at the bottom of 30. Then, the oil 33 at the bottom of the casing 30 enters the U-shaped pipe 32 through an oil return hole 34 opened below the oil level 35, and accompanying the gas refrigerant passing through the U-shaped pipe 32, the compressor 1 And 2 are stored in the housings 1a and 2a at the bottom thereof.

The housings 1a and 2a of the compressors 1 and 2 are connected to each other through an oil leveling pipe 25 which opens to the minimum required oil level positions 23 and 24, and the oil 21 stored at the bottom inside the housing 1a of the compressor 1 is provided. Further, the oil 22 stored in the inner bottom of the housing 2a of the compressor 2 moves mutually through the oil equalizing pipe 25, so that these oil levels 27 and 28 become equal.

During the heating operation, the four-way valve 36 is switched in the opposite manner as described above, and the refrigerant circulates in the direction opposite to that during the cooling operation, as indicated by the dashed arrow.

[0008]

In the above-mentioned conventional refrigeration cycle, the oil equalizing pipe 25 interconnecting the housings 1a and 2a of the compressors 1 and 2 has a certain thickness to keep the oil levels 27 and 28 equal. Therefore, the oil equalizing pipe 25 may be broken by the vibration of the compressors 1 and 2.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a first aspect of the present invention is a plurality of low-pressure housings connected in parallel to a refrigerant circuit. In a refrigeration cycle in which one accumulator is installed on the suction side of a type compressor, the accumulator has an oil return hole that opens into the oil stored at the bottom inside the casing of the accumulator, and has one end on the oil level of the oil. The other ends of the plurality of open outlet pipes are connected to the minimum required oil level position of the housing of each compressor via each suction pipe, and each of the suction pipes is installed at a position lower than the minimum required oil level position. The refrigeration cycle is characterized.

The gist of the second invention is to provide a refrigeration cycle in which one accumulator is installed on the suction side of a plurality of low-pressure housing type compressors connected in parallel to a refrigerant circuit. The oil level upper space of the oil stored at the bottom and the oil level upper space of the oil stored at the bottom inside the housing of each compressor are connected via independent suction pipes, and the lower part of the accumulator and The refrigeration cycle is characterized in that the minimum required oil level of the housing of the compressor is connected by independent oil return pipes, and these oil return pipes are set lower than the minimum required oil level.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. 40 is an accumulator and casing 47
And an inflow pipe 48 which is fixedly penetrating the top plate hermetically.
And the outflow pipes 41 and 42 fixedly penetrating the bottom plate of the casing 47 in a sealed manner.

The outflow pipes 41 and 42 rise substantially vertically, and the upper end thereof is the oil level of the oil 45 stored in the bottom of the casing 47.
46 is open above. The outlet pipes 41 and 42 are provided with oil return holes 43 and 44, respectively, which open below the oil surface 46.

The other end of the outflow pipe 41 is connected to the housing 1a of the compressor 1 via the suction pipe 5 and opens to the minimum required oil level 23 of the oil 21 stored in the inner bottom of the housing 1a. The other end of the outflow pipe 42 is connected to the compressor 2 via the suction pipe 6.
Of the oil 22 stored in the bottom of the housing 2a and open to the minimum required oil level position 24 of the oil 22.

The discharge pipes 5 and 6 are provided at lower positions than the minimum required oil level positions 23 and 24 of the compressors 1 and 2 over the entire length thereof. The other configuration is the same as that of the conventional one shown in FIG. 3, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

When the compressors 1 and 2 are operated, the gas refrigerant enters the casing 47 of the accumulator 40 from the inflow pipe 48, and the liquid refrigerant and the lubricating oil contained in the gas refrigerant in the space above the oil surface 46. Mist is separated. The gas refrigerant separated from the mist is sucked into the housing 1a of the compressor 1 through the outflow pipe 41 and the suction pipe 5, and the outflow pipe 42 and the suction pipe 6
And is sucked into the housing 2a of the compressor 2.

The mist separated from the gas refrigerant is temporarily stored in the bottom of the casing 47, gradually enters the outflow pipes 41 and 42 from the oil return holes 43 and 44, and is accompanied by the gas refrigerant passing through the outflow pipes 41 and 42. Then, they enter the housings 1a and 2a of the compressors 1 and 2 and are stored at the bottom thereof.

When one of the compressors 1 or 2, for example, 2 is operated and the other 1 is stopped, the pressure inside the housing 2a of the compressor 2 becomes low, so that the oil 45 in the accumulator 40 is filled with the oil return hole 44, After flowing into the housing 2a of the compressor 2 through the outflow pipe 42 and the suction pipe 6, the oil 22 in the housing 2a of the compressor 2
Although the oil level 28 of the oil 21 rises, the oil level 46 of the oil 45 in the accumulator 40 does not drop below the oil return hole 44, so that the oil level 27 of the oil 21 in the compressor 1 becomes the minimum required oil level. It does not drop below position 23.

When the compressors 1 and 2 are stopped, the compressor 1
The oil levels 27 and 28 of the oils 21 and 22 in the housings 1a and 2a of the first and second housings 2 and the oil level 46 of the oil 45 in the casing 47 of the accumulator 40 are equal.

A second embodiment of the present invention is shown in FIG. An inflow pipe 54 hermetically penetrating the top plate is fixed to a casing 53 of the accumulator 50, and the casing 53 is provided with a suction pipe 5 and a suction pipe 6 on a liquid level 52 of oil 51 stored at the bottom thereof. The oil levels 27, 22 of the oils 21, 22 stored in the bottoms of the housings 1a, 2a of the compressors 1, 2 via
Linked above 28.

The bottom of the casing 53 is connected to the housing 1a of the compressor 1 at the minimum required oil level position 23 via an oil return pipe 16 having a capillary tube 17, and has an oil return pipe having a capillary tube 19. It is connected via 18 to the housing 2a of the compressor 2 at its minimum required oil level position 24.

The oil return pipes 16 and 18 are provided at lower positions than the minimum required oil level positions 23 and 24 of the compressors 1 and 2 over the entire length thereof. The other configuration is the same as that of the conventional one shown in FIG. 3, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

Thus, when the compressors 1 and 2 are stopped, the oil 21 stored in the inner bottom of the housings 1a and 2a of the compressors 1 and 2
The oil 51 stored in the bottom of the casing 53 of the accumulator 50 and the oil 22 flows through the oil return pipes 16 and 18 so that the oil levels 27, 28 and 52 become equal.

During operation of the compressors 1 and 2, the accumulator
The gas refrigerant separated from the liquid refrigerant and the mist of the lubricating oil in the casing 53 is sucked into the housings 1a and 2a of the compressors 1 and 2 via the suction pipes 5 and 6.

The mist separated from the gas refrigerant is temporarily stored in the bottom of the casing 53 and gradually returns to the housing 1a of the compressor 1 through the oil return pipe 16 and the capillary tube 17, and at the same time, the oil return pipe 18 and the capillary tube 19 And gradually returns to the housing 2a of the compressor 2.

When one of the compressors 1 and 2, for example, 2 is operated and the other 1 is stopped, the pressure in the housing 2a of the compressor 2 becomes low, so that the oil in the accumulator 50 becomes low.
51 flows into the housing 2 a of the compressor 2 via the oil return pipe 18, and accordingly, the oil 21 in the compressor 1 flows into the accumulator 50 through the oil return pipe 16. Oil 21
Oil level 27 does not drop below the minimum required oil level position 23.

[0026]

According to the first aspect of the present invention,
It has an oil return hole that opens into the oil stored at the bottom of the accumulator casing, and the other end of each of a plurality of outflow pipes, one end of which opens on the oil surface of this oil, is connected to each compressor via each suction pipe. The oil separated from the refrigerant gas in the casing of the accumulator during operation of the multiple compressors is connected to the lowest required oil level position of the housing and each suction pipe is installed lower than the minimum required oil level position. Once, and gradually enters the outflow pipe through the oil return hole and returns to the inside of each compressor housing via the suction pipe with the gas refrigerant flowing therethrough.

When all the compressors are stopped, each oil return hole,
When the oil moves through the outflow pipe and the suction pipe, the oil level in the accumulator casing and the oil in the housing of each compressor become equal, and when some of the compressors are stopped, the oil inside the housing is reduced. Although the oil level of the oil drops, the oil level does not drop below the minimum required oil level position, so that poor lubrication and seizure of the compressor can be prevented. Further, since the conventional oil equalizing pipe connecting the inner bottom portions of the housings of the compressors to each other can be eliminated, troubles caused by breakage of the oil equalizing pipe can be avoided.

According to the second aspect of the present invention, the space above the oil level of the oil stored in the bottom of the casing of the accumulator and the space above the oil level of the oil stored in the bottom of the housing of each compressor. Independently connected via respective suction pipes, the lower part of the accumulator and the minimum required oil level of the housing of each compressor are connected by independent oil return pipes, and these oil return pipes are connected from the minimum required oil level. The oil separated from the gas refrigerant in the accumulator casing during operation of the multiple compressors is temporarily stored in the bottom of the casing during operation of the multiple compressors, and is gradually returned to the housing of each compressor through the oil return pipe. The refrigerant gas from which the oil has been separated is sucked into the upper space in the housing of each compressor through each suction pipe.

When all the compressors are stopped, the oil moves through the oil return pipe so that the oil level in the oil in the accumulator casing and the oil in the housing of each compressor becomes equal. When the compressor stops, the oil level of the oil in the housing drops, but does not drop below the minimum required oil level, so that poor lubrication and seizure of the compressor can be prevented. In addition, since the conventional oil equalizing pipe connecting the inner bottom portions of the housings of the compressors to each other can be eliminated, troubles caused by breakage of the oil equalizing pipe can be avoided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram of a conventional refrigeration cycle.

[Explanation of symbols]

 1, 2 Compressor 5, 6 Suction pipe 7 8 Discharge pipe 1a, 2a Housing 21, 22 Oil 23, 24 Minimum required oil level 27, 28 Oil level 40 Accumulator 47 Casing 45, Oil 41, 42 Outflow pipe 43, 44 Oil return hole

Claims (2)

[Claims] 1. A refrigerating cycle comprising a plurality of low-pressure housing-type compressors connected in parallel to a refrigerant circuit and having one accumulator installed on a suction side, wherein the accumulator has an opening in oil stored in a bottom of a casing of the accumulator. The other ends of a plurality of outlet pipes, one ends of which are opened on the oil level of the oil, are connected to the minimum required oil level positions of the housings of the compressors via the respective suction pipes. A refrigeration cycle, wherein each suction pipe is provided at a position lower than the minimum required oil level. 2. A refrigerating cycle in which one accumulator is installed on a suction side of a plurality of low-pressure housing type compressors connected in parallel to a refrigerant circuit, wherein an oil level of oil stored in a bottom portion of a casing of the accumulator is provided. The upper space and the upper surface of the oil level of the oil stored in the bottom of the housing of each of the compressors are connected via independent suction pipes, and the minimum oil level of the lower portion of the accumulator and the housing of each of the compressors is connected. And a refrigeration cycle, wherein the oil return pipes are connected to each other by independent oil return pipes, and these oil return pipes are installed at a position lower than the minimum required oil level.