JP3229109B2 - Refrigeration air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration and air-conditioning system in which a plurality of hermetic compressors are connected in parallel to one refrigerant system.

[0002]

2. Description of the Related Art FIG. 3 is a system diagram of a conventional air conditioner. This air conditioner includes an outdoor unit 1 and an indoor unit 2, and is connected via a connecting gas pipe 16 and a connecting liquid pipe 17. A plurality of outdoor units 1 (2 in the figure)
) Compressors 3 and 4, four-way switching valve 5, outdoor heat exchanger 6,
The accumulator 9 and the like are connected by a refrigerant pipe. The throttle 7 and the check valve 8 are connected in parallel to the liquid pipe 15, and a liquid return pipe 18 is connected from the bottom of the accumulator 9 to the upstream of the branch point A of the suction pipe 12. Further, the compressors 3 and 4 are connected to each other by an oil equalizing pipe 14 in a closed container forming an outer shell. 13 is a gas pipe connected to the accumulator. The indoor unit 2 is an indoor heat exchanger 1
0, an aperture 11 and the like. Note that a plurality of units (2 in the figure)
) Are connected in parallel to one refrigerant system.

[0003] In the present apparatus, during the cooling operation, the gas refrigerant discharged from the compressors 3 and 4 merges as shown by solid arrows, and then enters the outdoor heat exchanger 6 via the four-way switching valve 5. It is condensed and liquefied by releasing heat. The liquid refrigerant enters the indoor unit 2 via the check valve 8, the liquid pipe 15, and the connecting liquid pipe 17. Then, after being adiabatically expanded by being squeezed by the squeezer 11, it enters the indoor heat exchanger 10, where it cools the indoor air and evaporates. This gas refrigerant returns to the outdoor unit 1 via the connecting gas pipe 16,
The air is diverted through the four-way switching valve 5, the gas pipe 13, the accumulator 9, and the suction pipe 12, and is sucked into the compressors 3, 4. During the heating operation, the four-way switching valve 5 is switched in the opposite manner to the above, and the gas refrigerant discharged from the compressors 3 and 4 merges as shown by the dashed arrow, and then the four-way switching valve 5, the connecting gas pipe 16, and the indoor Indoor heat exchanger 10, throttle 11, connection liquid pipe 1 in unit 2
7, liquid tube 15 in outdoor unit 1, restrictor 7, outdoor heat exchanger 6, four-way switching valve 5, gas tube 13, accumulator 9,
The suction pipe 12 is split in this order and returns to the compressors 3 and 4.

Next, the flow of lubricating oil (hereinafter abbreviated as oil) during operation of the present apparatus will be described. Each compressor 3,
An oil used for lubricating sliding parts in the compressor is stored at the bottom of the closed container of No. 4. The oil is mixed in the gas refrigerant discharged from each of the compressors 3 and 4. Also,
The accumulator 9 may cause a case where the refrigerant does not completely evaporate and gasify in the evaporator (the indoor heat exchanger 10 during cooling and the outdoor heat exchanger 6 during heating) due to a sudden load change or the like. In order to prevent the remaining liquid refrigerant from being directly sucked into the compressors 3 and 4, the refrigerant that has entered the accumulator 9 from the gas pipe 13 is a liquid refrigerant part that has not evaporated and oil mixed therein. Separated. The liquid mixture of the separated liquid refrigerant and oil passes through the liquid return pipe 18 connected to the bottom of the accumulator 9, joins the suction pipe 12, and is sucked into each of the compressors 3 and 4. Thus, the oil discharged from the compressors 3 and 4 circulates through the refrigerant circuit and returns to the compressors 3 and 4.

[0005]

In the above-mentioned conventional air conditioner, even when the compressor 3 is driven and the compressor 4 is stopped, the refrigerant is supplied to the suction pipe 12 by the suction force of the compressor 3. A suction pipe of the compressor 4 branched at a branch point A of
It is sucked into the compressor 3 through the closed container of the compressor 4 and the oil equalizing pipe 14. Due to this flow, the mixed liquid of the oil and the liquid refrigerant in the accumulator 9 flows into the compressor 4, and the oil in the closed container of the compressor 4 is diluted.

[0006] When the compressor 4 is restarted in a state where the oil in the closed container is diluted with the liquid refrigerant, the liquid refrigerant mixed in the oil boils. Do not deteriorate the oil suction of the oil pump. As a result, the lubrication of the sliding part is deteriorated, and there is a possibility that abnormal wear, heat generation, seizure and other failures due to poor lubrication may occur.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and prevent a liquid refrigerant from flowing into a stopped compressor to prevent a failure such as poor lubrication when the compressor is restarted.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems , and comprises connecting a plurality of hermetic compressors to one refrigerant system in parallel and connecting the hermetic compressors to the plurality of hermetic compressors.
Suction gas piping with an accumulator, the luck from the bottom of the accumulator <br/> Correlator, where the mixed liquid of the separated savings reservoir oils and liquid refrigerant within said plurality of hermetic compressor
The present invention relates to a refrigeration / air-conditioning apparatus provided with a liquid return pipe for returning using a suction pressure during rotation, and having the following features. (1) a liquid return pipe from the previous SL accumulator, said plurality
The closed containers of the two closed compressors are connected to a connecting pipe connecting them , and separated by the accumulator via the liquid return pipe.
A plurality of hermetic compressors using the mixed liquid of the oil and liquid refrigerant
Using the suction pressure to return to the operating compressor
As to the thing. (2) above (1) in refrigeration and air conditioning apparatus according to claim, before
The connecting pipe is an oil equalizing pipe. (3) above (1) in refrigeration and air conditioning apparatus according to claim, before
The connecting pipe must be a pressure equalizing pipe.

[0009]

According to the present invention, since a part of the plurality of compressors is stopped, the oil and the liquid refrigerant flowing from the accumulator to the connecting pipe via the liquid return pipe are provided when the compressor is stopped. Since the connecting liquid, for example, an oil equalizing pipe or a pressure equalizing pipe, is connected to a plurality of compressors, the mixed liquid is not sucked into a stopped compressor having no suction force, and the entire amount of the mixed liquid is compressed during driving. Sucked into the machine. Therefore, the mixed liquid from the accumulator does not flow into the stopped compressor, and the oil in the closed container is not diluted by the liquid refrigerant.

[0010]

FIG. 1 is a system diagram of a refrigeration / air-conditioning apparatus according to a first embodiment of the present invention. A plurality of (two in the figure) compressors 3,
4 are mounted in parallel in one refrigerant system, and the sealed containers forming these outer shells are connected to each other through an oil equalizing pipe 14. Also, a liquid return pipe 18 ′ is provided from the bottom of the accumulator 9.
Are connected to the oil equalizing pipe 14. When the compressors 3 and 4 are operated together, the liquid refrigerant and oil mixture collected at the bottom of the accumulator 9 passes through the liquid return pipe 18 ′ and passes to the compressors 3 and 4 via the oil equalizing pipe 14. Inflow. Compressor 3,
The oil discharged from 4 circulates through the refrigerant circuit and returns to the compressors 3 and 4.

In the present embodiment, as described in the subject, when one compressor (for example, the compressor 4) is stopped,
Since the suction force of the compressor 4 disappears, all the mixed liquid flowing into the oil equalizing pipe 14 is sucked into the compressor 3 and does not flow into the compressor 4, but the oil in the closed container is diluted with the liquid refrigerant. Never. Therefore, when the compressor 4 is restarted, the oil level in the sealed container does not boil, and the oil suction of the oil pump (not shown) mounted in the compressor 4 does not deteriorate. Further, the possibility of causing a failure due to poor lubrication is also eliminated. Other configurations and operations are the same as those of the conventional one shown in FIG. 3, and corresponding members are denoted by the same reference numerals.

FIG. 2 is a system diagram of a refrigeration / air-conditioning apparatus according to a second embodiment of the present invention. A plurality of (two in the figure) compressors 3 and 4 are mounted in parallel in one refrigerant system, and the hermetic containers forming the outer shell are connected via an equalizing pipe 19. A liquid return pipe 18 ″ is connected to the pressure equalizing pipe 19 from the bottom of the accumulator 9. In addition, 20, 21
Is an oil retainer for storing the required amount of oil in the closed containers of the compressors 3 and 4, and the oil return pipes 22 and 23, the oil supply pipes 24 and
25.

As described above, in the second embodiment, the connection of the liquid return pipe 18 from the bottom of the accumulator 9 is changed from the oil equalizing pipe 14 of the first embodiment to the pressure equalizing pipe 19. Functions and effects exactly the same as the examples can be exerted. Other configurations and operations are the same as those of the conventional one shown in FIG. 3, and corresponding members are denoted by the same reference numerals.

In each of the embodiments described in detail above, since the liquid return pipe from the accumulator is connected to the connecting pipe connecting the sealed containers of the compressors to each other, one of the plurality of compressors is used. When the parts are stopped, the mixed liquid of oil and liquid refrigerant that has flowed from the accumulator through the liquid return pipe into the connecting pipe is not sucked into the stopped compressor that has lost suction power, and the entire amount thereof is not Is sucked into the driven compressor. Therefore, the mixed liquid from the accumulator does not flow into the stopped compressor, and the oil in the closed container is not diluted by the liquid refrigerant. Therefore, when the compressor is stopped, the oil level in the closed vessel does not boil, the oil suction performance of the oil pump does not deteriorate, and sufficient oil is supplied to the sliding portion in the compressor. Is done.
Therefore, it is possible to eliminate the risk of causing troubles such as abnormal wear, heat generation, and seizure due to poor lubrication.

[0015]

In the refrigerating and air-conditioning apparatus of the present invention, the liquid return pipe from the accumulator is connected to the connecting pipes connecting the closed containers of the compressors to each other, or the connecting pipe is an oil equalizing pipe, Alternatively, since the connecting pipe is a pressure equalizing pipe, when a part of the plurality of compressors is stopped, the mixed liquid of the oil and the liquid refrigerant does not flow into the stopped compressor. Therefore, it is possible to prevent troubles such as boiling of the liquid refrigerant and associated lubrication failure when the stopped compressor is restarted.

[Brief description of the drawings]

FIG. 1 is a system diagram of a refrigeration / air-conditioning apparatus according to a first embodiment of the present invention.

FIG. 2 is a system diagram of a refrigeration / air-conditioning apparatus according to a second embodiment of the present invention.

FIG. 3 is a system diagram of a conventional refrigeration / air-conditioning apparatus.

[Explanation of symbols]

 Reference Signs List 3 Compressor 4 Compressor 9 Accumulator 14 Oil equalizing pipe 18 Liquid return pipe 18 'Liquid return pipe 18' 'Liquid return pipe 19 Pressure equalizing pipe

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Ogawa 60-1 Kutsubo, Iwazuka-cho, Naka-ku, Nagoya-shi Inside Nakanishi Engineering Co., Ltd. (56) References Japanese Utility Model Showa 64-49679 (JP, U) 57-157778 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 39/02 F04B 41/02 F04B 41/06

Claims (3)

(57) [Claims] 1. A plurality of hermetic compressors are connected in parallel to one refrigerant system, and a plurality of hermetic compressors are connected to each other.
Comprising an accumulator to inlet gas pipe, the accumulator from the bottom of <br/> data, where the separated thereof during operation a mixture of the savings reservoir oils and liquid refrigerant within said plurality of hermetic compressors
In the refrigerating and air-conditioning apparatus provided with a liquid return pipe for returning utilizing suction pressure of the liquid return pipe from the previous SL accumulator, connected to the connecting pipe which connects the sealed container of the plurality of hermetic compressors with each other The accumulator through the liquid return pipe
The mixed liquid of oil and liquid refrigerant separated by the
The suction pressure is applied to the operating compressor among the hermetic compressors.
A refrigeration and air-conditioning system characterized by utilizing and returning . 2. A previous SL connecting tube, refrigeration and air conditioning apparatus according to claim 1, characterized in that the oil-equalizing pipe. 3. A pre-Symbol connecting tube, refrigeration and air conditioning apparatus according to claim 1, characterized in that the pressure equalizing pipe.