CN1318145A - Refrigerating device - Google Patents

Abstract

A refrigerating device, wherein an oil return mechanism (Z) returning a refrigerating machine oil separated from suction gas refrigerant preferentially to a compressor (1A) of a minimum capacity among compressors (1A, 1B) having the capacities different from each other is provided in a suction line (X) of the compressors (1A, 1B), and an oil return passage (117) returning the refrigerating machine oil separated in an oil separator (116) installed in a delivery pipe (115) of the compressors (1A, 1B) to the compressor (1A) of the minimum capacity among the compressors (1A, 1B, ---) is provided, whereby the refrigerating machine oil separated in the oil separator (116) and the refrigerating machine oil in the suction gas refrigerant are returned sequentially to the compressor (1B) having a low dome internal pressure after they return preferentially to the compressor (1A) of the minimum capacity.

Description

refrigeration unit

technical field

The invention relates to an oil return structure facing a compressor in a refrigeration device.

Background technique

In a refrigerating apparatus in which a plurality of (for example, two) compressors are connected in parallel, the capacities of the respective compressors are often different. In such a refrigeration device, when all the compressors are in operation, the internal pressures of the dome chambers (dome) of the respective compressors are different. In addition, the refrigerating machine oil at the bottom of the dome cavity in the compressor moves from a compressor with a high internal pressure to a compressor with a low internal pressure through a pressure equalizing pipe.

As long as the operation in this state continues, the refrigerating machine oil of the compressor whose pressure is high in the dome chamber continues to move to the compressor whose pressure is low in the dome chamber. If this state continues, the refrigerating machine oil of the compressor with high pressure in the dome cavity will be exhausted and the compressor will be damaged.

In order to solve the above-mentioned undesirable phenomenon, there is a method of oil equalization operation control. This oil equalization operation control is to alternately operate the compressors at regular intervals to ensure the amount of refrigerating machine oil in each compressor.

However, when the above-mentioned oil equalization operation control is performed, all the compressors can only be operated simultaneously for a certain period of time. As a result, there is a problem that the required capacity of the refrigeration unit cannot be obtained.

In view of the above-mentioned problems, an object of the present invention is to provide a refrigerator equipped with a plurality of compressors having different capacities, which can reliably perform return flow of refrigerator oil to the respective compressors.

disclosure of invention

In order to solve the above-mentioned problems, the present invention takes the following measures.

The 1st invention is aimed at the refrigeration apparatus provided with the refrigerant circuit A which has several compressors 1A, 1B... which are mutually connected in parallel and which differ in capacity. And in order to distribute the refrigerating machine oil in the refrigerant circulating in the refrigerant circuit A to the compressors 1A, 1B... according to the different capacities of the compressors 1A, 1B..., a device is provided to return the refrigerating machine oil to the compressors. Dispensing mechanism R for 1A, 1B...

In the first invention, when the compressors 1A, 1B... are operating, the refrigerating machine oil is distributed for each compressor 1A, 1B.... Therefore, it is possible to ensure refrigeration machine oil for the plurality of compressors 1A, 1B... even without performing the oil equalization operation control for alternately operating the compressors as in the past.

The 2nd invention is aimed at the refrigerating apparatus provided with the refrigerant circuit A which has the some compressor 1A, 1B... which is connected in parallel and which differs in capacity. In addition, in order to distribute the refrigerating machine oil in the refrigerant circulating in the refrigerant circuit A from the compressor 1A with the smallest capacity to the other compressors 1B..., distribution of the refrigerating machine oil returning to the compressors 1A, 1B... Institution R.

In the second invention, when the compressors 1A, 1B... are operating, the refrigerating machine oil is distributed from the compressor 1A with the smallest capacity to the other compressors 1B.... Therefore, it is possible to ensure refrigeration machine oil for the plurality of compressors 1A, 1B... even without performing the oil equalization operation control for alternately operating the compressors as in the past.

The 3rd invention is aimed at the refrigerating apparatus provided with the refrigerant circuit A which has the some compressor 1A, 1B... which is connected in parallel and which differs in capacity. In addition, in order to distribute the refrigerating machine oil in the refrigerant circulating in the refrigerant circuit A from the compressor 1A with the largest capacity to the other compressors 1B..., distribution of the refrigerating machine oil returning to the compressors 1A, 1B... Institution R.

In the third invention, when the compressors 1A, 1B... are operating, the refrigerating machine oil is distributed from the compressor 1A having the largest capacity to the other compressors 1B.... Therefore, it is possible to ensure refrigeration machine oil for the plurality of compressors 1A, 1B... even without performing the oil equalization operation control for alternately operating the compressors as in the past.

In the fourth invention, in the above-mentioned second invention, the compressors 1A, 1B... are low pressure dome cavity compressors. In addition, the distribution mechanism R has an oil equalizing pipe 109 communicated with the compressors 1A, 1B... and an oil separator 116 for separating and discharging the refrigerating machine oil on the discharge side of the compressors 1A, 1B.... The refrigerating machine oil separated by the oil separator 116 and the refrigerating machine oil contained in the suction refrigerant of the compressors 1A, 1B, . . . are preferentially returned to the compressor 1A having the smallest capacity.

In the fourth invention, the refrigerating machine oil discharged from the compressors 1A, 1B, . . . is collected by the oil separator 116 . The refrigerating machine oil in the oil separator 116 and the refrigerating machine oil returning to the suction side of the compressors 1A, 1B, . . . are preferentially returned to the compressor 1A with the smallest capacity. Then, due to the pressure difference in the dome cavity, the compressor 1A with the smallest capacity flows back to the compressors 1B, 1C, .

In the fifth invention, in the above-mentioned third invention, the compressors 1A, 1B... are high-pressure dome cavity compressors. In addition, the distribution mechanism R has an oil equalizing pipe 48 communicating with the compressors 1A, 1B... and an oil separator 36 for separating and discharging the refrigerant from the refrigerant on the discharge side of the compressors 1A, 1B.... The refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil contained in the suction refrigerant of the compressors 1A, 1B, .

In the fifth invention, the refrigerating machine oil discharged from the compressors 1A, 1B, . . . is recovered by the oil separator 36 . The refrigerating machine oil in the oil separator 36 and the refrigerating machine oil flowing back to the suction side of the compressors 1A, 1B, . . . are preferentially returned to the compressor 1A with the largest capacity. Then, due to the pressure difference in the dome cavity, the compressor 1A with the largest capacity flows back to the compressor 1B with the lower pressure in the dome cavity through the oil equalizing pipe 48 . . .

The sixth invention has a plurality of low-pressure dome-type compressors 1A, 1B, ... of different capacities connected in parallel to each other in parallel through refrigerant piping, a heat source side exchanger 2, a decompression mechanism 3, and a use side heat exchanger 4 The refrigerant circuit A to be connected is intended for a refrigeration device in which the compressors 1A, 1B, .

In addition, an oil separator 16 for separating refrigerating machine oil in the discharged gas refrigerant is provided on the discharge piping 15 of the compressors 1A, 1B..., and in the suction line X of the compressors 1A, 1B... , the oil return mechanism Z for the compressor 1A that preferentially returns the refrigerating machine oil contained in the suction gas refrigerant to the minimum capacity of the compressors 1A, 1B... is provided. In addition, an oil return passage 37 for the compressor 1A having the smallest capacity among the compressors 1A, 1B, .

In the sixth invention, when the compressors 1A, 1B, . Then, the refrigerating machine oil returns from the smallest capacity compressor 1A to the dome chamber in order due to the internal pressure difference of the dome chamber (internal pressure of compressor 1A > internal pressure of compressor 1B > internal pressure of compressor 1C > . . . ). Compressors 1B, 1C... with low pressure in the top chamber. Therefore, it is possible to ensure refrigeration machine oil for the plurality of compressors 1A, 1B... even without performing the oil equalization operation control for alternately operating the compressors as in the past.

The seventh invention is the above-mentioned sixth invention, wherein the oil return mechanism Z includes: a substantially horizontal structure that forms a part of the suction line X and is connected to the compressor 1A with the smallest capacity among the compressors 1A, 1B, . . . The suction pipe 25 of a certain length and the second suction pipe 25 branched from the upper part of the first suction pipe 25 and respectively connected to the compressors 1B, 1C other than the compressor 1A with the smallest capacity among the compressors 1A, 1B... Piping 26, 26 . . .

In the first suction pipe 25 of the seventh invention, the refrigerating machine oil is separated due to the difference in specific gravity between the refrigerating machine oil and the gas refrigerant, and flows to the bottom of the pipe. The separated refrigerating machine oil is returned from the first suction pipe 25 to the compressor 1A with the smallest capacity. Therefore, since it is easy to change the piping structure, the refrigerator oil in the compressors 1A, 1B, . . . can be ensured at low cost and efficiently.

The eighth invention is the above-mentioned sixth invention, wherein the oil return mechanism Z includes: a vertical pipe 27 that forms a part of the suction line X and is downwardly opened at the lower end; The pipe body 28 whose area is larger than the vertical pipe 27; the first suction pipe 25 connected to the lower end of the pipe body 28 and connected to the compressor 1A with the smallest capacity among the compressors 1A, 1B...; The side walls of 28 are connected to the second suction pipes 26 , 26 . . . that are connected to compressors 1B, 1C .

In the eighth invention, since the suction gas refrigerant flowing into the pipe body 28 from the vertical pipe 27 rapidly expands in the pipe body 28, the refrigerating machine oil and the suction gas refrigerant are separated. The separated refrigerating machine oil returns from the first suction pipe 25 to the compressor 1A with the smallest capacity due to gravity and inertia. Therefore, since it is easy to change the piping structure, it is possible to secure the refrigerating machine oil in the compressors 1A, 1B, . . . at low cost.

The ninth invention is that in the sixth invention above, the oil return mechanism Z includes: a horizontal large-diameter pipe 29 that constitutes a part of the suction line X and has a vertical cross-sectional area larger than the suction line X; 29 the first suction pipe 25 connected to the pipe wall and connected to the compressor 1A with the smallest capacity among the compressors 1A, 1B...; The second suction pipes 26, 26... to which the compressors 1B, 1C... other than the compressor 1A with the smallest capacity among the above-mentioned compressors 1A, 1B... are connected.

In the ninth invention, since the flow velocity of the suction gas refrigerant flowing through the horizontal large-diameter tube 29 can be eased, an annular flow of the refrigerating machine oil is generated on the tube wall side where the flow velocity is slow, and the suction gas refrigerant and the refrigerating machine oil are separated. The separated refrigerating machine oil is returned from the first suction pipe 25 to the compressor 1A with the smallest capacity. Therefore, since it is easy to change the piping structure, the refrigerator oil in the compressors 1A, 1B, . . . can be ensured at low cost and efficiently.

A tenth invention is any one of the seventh to ninth inventions, wherein the oil return passage 17 is connected to the first suction pipe 25 .

In the tenth invention, the refrigerating machine oil separated by the oil separator 36 joins the refrigerating machine oil separated from the suction gas refrigerant in the first suction pipe 25, and returns to the compressor 1A with the smallest capacity. As a result, there is no need to change the structure of the compressor 1A (such as the casing structure, etc.).

The eleventh invention comprises a pair of high-pressure dome-chamber compressors 1A and 1B with different capacities, which are sequentially connected in parallel through refrigerant piping, a four-way switching valve 2, a heat source side heat exchanger 3, and a decompression mechanism. 4 and the refrigerant circuit A connected to the use-side heat exchanger 5, and a refrigeration device in which the compressors 1A and 1B communicate with each other through the oil equalizing pipe 48.

In addition, an oil separator 36 for separating refrigerating machine oil in the discharged gas refrigerant is provided on the discharge piping 47 of the compressors 1A and 1B, and the refrigerating machine oil separated by the oil separator 36 is returned to the discharge pipe 47. The oil return passage 37 on the suction side of the compressors 1A, 1B. In addition, in the oil return passage 37, an on-off valve 39 that is closed when the compressors 1A and 1B are both stopped is provided.

In the eleventh invention, when the compressors 1A and 1B are operated together, the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil in the sucked gas refrigerant pass through the oil return passage 37 and return to the compressors 1A and 1B, respectively. At this time, most of the refrigerating machine oil is returned to the compressor 1A having a large capacity. The internal pressure of the compressor 1A having a large capacity is higher than the internal pressure of the compressor 1B having a small capacity. As a result, the refrigerating machine oil moves from the large-capacity compressor 1A to the small-capacity compressor 1B through the oil equalizing pipe, and reliably flows back to both compressors 1A and 1B.

Therefore, it is possible to secure the refrigerating machine oil for the compressors 1A and 1B without performing the oil equalization operation control for the alternate operation of the compressors as conventionally done. Furthermore, when the compressors 1A and 1B are both stopped, the on-off valve 39 is closed, and the oil return passage 37 is in a non-communicating state. Therefore, the refrigerant does not flow from the oil separator 36 to the suction side of the compressor 1A during the shutdown period.

The twelfth invention comprises a pair of high-pressure dome-type compressors 1A and 1B with different capacities, a four-way switching valve 2, a heat source side heat exchanger 3, and a decompression mechanism 4, which are sequentially connected in parallel through refrigerant piping. , the refrigerant circuit A connected to the use-side heat exchanger 5 , and a refrigeration device in which the compressors 1A and 1B communicate with each other through the oil equalizing pipe 48 .

In addition, the discharge pipes 47 of the compressors 1A and 1B are provided with an oil separator 36 for separating the refrigerating machine oil in the discharged gas refrigerant, and the refrigerating machine oil separated in the oil separator 36 is respectively returned to Oil return passages 37A, 37B to the suction side of said compressors 1A, 1B. In addition, in the oil return passages 37A, 38B, on-off valves 39A, 39B that are closed when the compressors 1A, 1B stop operating together are provided, respectively.

In the twelfth invention, when the compressors 1A and 1B are operated together, the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil in the suction gas refrigerant are returned to the compressors 1A and 1B through the oil return passages 37A and 37B, respectively. . At this time, most of the refrigerating machine oil returns to the compressor 1A with a large capacity. The internal pressure of the compressor 1A having a large capacity is higher than the internal pressure of the compressor 1B having a small capacity. As a result, the refrigerating machine oil moves from the large-capacity compressor 1A to the small-capacity compressor 1B through the oil equalizing pipe 48, and reliably flows back to both compressors 1A and 1B.

Therefore, it is possible to secure the refrigerating machine oil for the compressors 1A and 1B without performing the oil equalization operation control for the alternate operation of the compressors as conventionally done. Furthermore, while the compressors 1A, 1B are both stopped, the on-off valves 39A, 39B are closed, and the oil return passages 37A, 37B are in a non-communicating state. Therefore, when the operation of the refrigerant is stopped, the refrigerant does not flow from the oil separator 36 to the suction side of the compressors 1A, 1B.

According to a thirteenth invention, in any one of the above-mentioned eleventh and twelfth inventions, the oil equalizing pipe 48 is provided with an on-off valve 49 which is closed when one of the compressors 1A and 1B is stopped.

In the thirteenth invention, when one of the compressors 1A and 1B is stopped, the on-off valve 49 is closed to prohibit movement of the refrigerating machine oil through the oil equalizing pipe 48 . As a result, the migration of the refrigerating machine oil from the operating compressor to the stopped compressor can be prevented, and the refrigerating machine oil shortage will not occur in the operating compressor.

The fourteenth invention comprises a pair of high-pressure dome-type compressors 1A and 1B with different capacities, a four-way switching valve 2, a heat source side heat exchanger 3, and a decompression mechanism 4, which are sequentially connected in parallel through refrigerant piping. The refrigerant circuit A connected to the use-side heat exchanger 5 and the refrigeration device in which the compressors 1A and 1B communicate with each other through the oil equalizing pipe 48 are targeted.

In addition, an oil separator 36 for separating the refrigerating machine oil in the discharged gas refrigerant is provided on the discharge piping 47 of the compressors 1A and 1B, and an oil separator 36 is provided to return the separated refrigerating machine oil to the discharge pipe 47. Oil return passage 37 to the suction side of said compressors 1A, 1B. In addition, the oil equalizing pipe 48 is provided with an on-off valve 49 that is closed when one of the compressors 1A and 1B stops operating.

In the fourteenth invention, when the compressors 1A and 1B operate together, the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil in the suction gas refrigerant pass through the oil return passage 37 and return to the compressors 1A and 1B, respectively. At this time, most of the refrigerating machine oil returns to the compressor 1A with a large capacity. The internal pressure of the compressor 1A having a large capacity is higher than the internal pressure of the compressor 1B having a small capacity. As a result, the refrigerating machine oil moves from the compressor 1A with a large capacity to the compressor 1B with a small capacity through the oil equalizing pipe 48, and flows back to both compressors 1A and 1B reliably.

Therefore, it is possible to secure the refrigerating machine oil for the compressors 1A and 1B without performing the oil equalization operation control for the alternate operation of the compressors as conventionally done.

Furthermore, when one of the compressors 1A, 1B is stopped, the on-off valve 49 is closed, and the movement of the refrigerating machine oil through the oil equalizing pipe 48 is prohibited. As a result, the migration of the refrigerating machine oil from the operating compressor to the stopped compressor can be prevented, and the refrigerating machine oil shortage will not occur in the operating compressor.

According to a fifteenth invention, in any one of the eleventh, twelfth and fourteenth inventions, the suction pipe 38 of the compressor 1A, 1B is located below the suction port 50A, 50B of the compressor 1A, 1B.

In the fifteenth invention, when the compressor with a large capacity is stopped and the compressor with a small capacity is in operation, the refrigerating machine oil can be prevented from flowing into the compressor with a large capacity through the suction pipe 38 .

According to the present invention, since the refrigerating machine oil is returned to the respective compressors 1A, 1B by utilizing the difference in capacity of the compressors 1A, 1B..., it is not necessary to perform the oil equalization operation control of alternate operation of the compressors as in the past. As a result, refrigeration machine oil for the plurality of compressors 1A, 1B, .

According to the sixth invention, when the compressors 1A and 1B are in operation, the refrigerating machine oil separated by the oil separator 116 and the refrigerating machine oil in the sucked gas refrigerant return preferentially to the compressor 1A with the smallest capacity, and the inside of the dome cavity The pressure difference (internal pressure of compressor 1A > internal pressure of compressor 1B > internal pressure of compressor 1C > . . . ) returns in order from this compressor 1A to compressors 1B, 1C where the pressure in the dome chamber is low. As a result, refrigeration machine oil for the plurality of compressors 1A, 1B, .

According to the seventh invention, since the refrigerating machine oil is separated in the first suction pipe 125 due to the difference in specific gravity between the refrigerating machine oil and the gas refrigerant, and flows into the bottom of the pipe, the separated refrigerating machine oil flows back to the compressor through the first suction pipe 125 Compressor 1A with the smallest capacity among 1A and 1B. Since it is easy to change the piping structure, the refrigerator oil in the compressors 1A, 1B, . . . can be secured at low cost and efficiently.

According to the eighth invention, since the suction gas refrigerant flowing into the pipe body 128 from the vertical pipe 127 expands rapidly in the pipe body 128, the refrigerating machine oil is separated from the suction gas refrigerant, and the separated refrigerating machine oil passes through gravity and inertia. The first suction pipe 125 returns to the compressor 1A with the smallest capacity among the compressors 1A, 1B, . . . . As a result, since changing the piping structure is simple, the refrigerator oil in the compressors 1A, 1B, . . . can be efficiently secured at low cost.

According to the ninth invention, since the flow velocity of the suction gas refrigerant flowing through the horizontal large-diameter tube 129 can be eased, an annular flow of refrigerating machine oil is generated on the side of the tube wall where the flow velocity is slow, and the refrigerating machine oil and the suction gas refrigerant are separated. , the separated refrigerating machine oil returns to the compressor 1A with the smallest capacity among the compressors 1A, 1B... through the first suction pipe. As a result, since changing the piping structure is simple, the refrigerator oil in the compressors 1A, 1B, . . . can be efficiently secured at low cost.

According to the tenth invention, the refrigerating machine oil separated by the oil separator 116 joins the refrigerating machine oil separated from the suction gas refrigerant in the first suction pipe 125 and returns to the compressor 1A with the smallest capacity. As a result, there is no need to change the configuration of the compressor 1A (such as the housing structure, etc.).

According to the eleventh invention, when the compressors 1A and 1B are operated together, the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil sucked into the refrigerant return to the compressors 1A and 1B through the oil return passage 37, respectively. Moreover, most of the refrigerating machine oil flows back to the compressor 1A with a large capacity, but since the internal pressure of the compressor 1A with a large capacity is greater than the internal pressure of the compressor 1B with a small capacity, the refrigerating machine oil passes through the oil equalizing pipe 48 and is compressed to the compressor with a small capacity. Machine 1B moves. As a result, the flow back to both compressors 1A, 1B is assured. Refrigerating machine oil for the compressors 1A and 1B can be ensured even if the oil equalization operation control for the compressor alternate operation is not performed as conventionally.

In addition, when the compressors 1A and 1B are both stopped, the on-off valve 39 is closed to make the oil return passage 37 non-communicating, so that the refrigerant does not flow from the oil separator 36 to the suction side during the stop.

In the twelfth invention, when the compressors 1A, 1B are operated together, the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil in the suction gas refrigerant are returned to the compressors 1A, 1B through the oil return passages 37A, 37B, respectively. . In addition, most of the refrigerating machine oil is returned to the compressor 1A with a large capacity, but since the internal pressure of the compressor 1A with a large capacity is greater than the internal pressure of the compressor 1B with a small capacity, the refrigerating machine oil passes through the oil equalizing pipe 48 and is compressed to the compressor with a small capacity. Machine 1B moves. As a result, the refrigerating machine oil of the compressors 1A and 1B can be ensured without performing the equalization operation control of the oil in which the compressors are alternately operated as in the past, since the oil is reliably returned to the compressors 1A and 1B.

In addition, when the compressors 1A and 1B stop operating together, the on-off valves 39A and 38B are closed so that the oil return passages 37A and 37B are in a non-communicative state. Therefore, the refrigerant will not flow from the oil separator 36 when the operation is stopped. flow to the suction side.

According to the thirteenth invention, when one of the compressors 1A, 1B stops operating, the on-off valve 49 performs a closing operation, and the movement of the refrigerating machine oil through the oil equalizing pipe 48 is prohibited. As a result, the migration of the refrigerating machine oil from the operating compressor to the stopped compressor can be prevented, and the refrigerating machine oil shortage will not occur in the operating compressor.

According to the fourteenth invention, when the compressors 1A and 1B are operated together, the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil in the suction gas refrigerant pass through the oil return passage 37 and return to the compressors 1A and 1B, respectively. Moreover, most of the refrigerating machine oil flows back to the compressor 1A with a large capacity, but since the internal pressure of the compressor 1A with a large capacity is greater than the internal pressure of the compressor 1B with a small capacity, the refrigerating machine oil passes through the oil equalizing pipe 48 and is compressed to the compressor with a small capacity. Machine 1B moves. As a result, the refrigerating machine oil of the compressors 1A and 1B can be ensured without performing the equalization operation control of the oil in which the compressors are alternately operated as in the past, since the oil is reliably returned to the compressors 1A and 1B.

Furthermore, when one of the compressors 1A and 1B is stopped, the on-off valve 48 is closed so that the refrigerating machine oil passing through the oil equalizing pipe 48 cannot move. As a result, the movement of the refrigerating machine oil from the compressor in operation to the compressor in the stopped state is inhibited, so that the compressor in operation will not be short of refrigerating machine oil.

According to the fifteenth invention, when the compressor with a large capacity is stopped and the compressor with a small capacity is in operation, refrigerating machine oil can be prevented from flowing into the compressor with a large capacity through the suction pipe 38 .

A brief description of the drawings

Fig. 1 is a diagram of a refrigerant piping system of a refrigeration device according to a first embodiment of the present invention.

Fig. 2 is a piping system diagram showing the partial structure of the suction line in the refrigerating apparatus according to the first embodiment of the present invention.

Fig. 3 is a piping system diagram showing a partial structure of a suction line in a refrigerating apparatus according to a second embodiment of the present invention.

Fig. 4 is a piping system diagram showing a partial structure of a suction line in a refrigerating apparatus according to a third embodiment of the present invention.

Fig. 5 is a piping system diagram showing a partial structure of a suction line in a refrigerating apparatus according to a fourth embodiment of the present invention.

Fig. 6 is a refrigerant circuit diagram of a refrigeration system according to a fifth embodiment of the present invention.

Fig. 7 is a piping system diagram showing a partial structure of a suction pipe in a refrigerating apparatus according to a fifth embodiment of the present invention.

Fig. 8 is an explanatory table showing the operating states of the compressor and its electromagnetic on-off valve in the refrigeration system according to the sixth embodiment of the present invention.

Fig. 9 is a piping system diagram showing a partial structure of a suction pipe in a refrigerating apparatus according to a sixth embodiment of the present invention.

The best form for carrying out the invention

Next, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a refrigerant piping system of a refrigeration device according to a first embodiment of the present invention.

As shown in Fig. 1, this refrigeration device has two compressors 1A and 1B with different capacities connected in parallel, an air-cooled condenser 102 serving as a heat source side heat exchanger, and an expansion valve 103 serving as a decompression mechanism. And a refrigerant circuit A configured by sequentially connecting a pair of evaporators 104 and 104 connected in parallel and functioning as use-side heat exchangers through refrigerant piping.

Wherein, the capacity of the first compressor 1A is 4HP, and the capacity of the second compressor 1B is 5HP. The oil storage part of the first compressor 1A is connected to the oil storage part of the second compressor 1B through an oil equalizing pipe 109 .

Between the condenser 102 and the expansion valve 103, there is a storage tank 105 connected to the outlet side of the condenser 102, and a second unit for supercooling the liquid refrigerant from the liquid phase part of the storage tank 105 by using outdoor air. A subcooling heat exchanger 106 and a second subcooling heat exchanger 107 for further subcooling the subcooled liquid refrigerant from the first subcooling heat exchanger 106 by latent heat of evaporation of the gas-liquid mixed refrigerant. One outdoor fan 108 is provided between the condenser 102 and the first subcooling heat exchanger 106 .

A part of the liquid refrigerant from the liquid phase portion of the accumulator tank 105 is decompressed through the thermosensing expansion valve 110 and supplied to the second subcooling heat exchanger 107 . The thermosensitive cylinder of the thermosensitive expansion valve 110 is provided on the gas piping 112 connecting the second subcooling heat exchanger 107 to the suction pipe 111 constituting a part of the suction line X of the compressors 1A and 1B. 110a. That is, the opening degree of the thermosensitive expansion valve 110 is controlled according to the temperature of the gas refrigerant flowing through the gas pipe 112 .

In the refrigerant circuit A, a hot gas bypass circuit 113 that connects the discharge side and the suction side of the compressors 1A, 1B is provided. In the hot gas bypass circuit 113, an electromagnetic on-off valve 114 is installed. When the low pressure is too low, the electromagnetic on-off valve 114 will open to prevent vacuum operation.

An oil separator 116 for separating refrigerating machine oil contained in the gas refrigerant is provided on the discharge pipe 115 of the compressors 1A, 1B. The refrigerating machine oil separated by the oil separator 116 returns to the compressor 1A of the smallest capacity through the oil return passage 117 as will be described later. In the oil return channel 117, an electromagnetic on-off valve 118 and a capillary tube 119 that are opened during oil return are provided.

An indoor fan 120 is provided on the evaporators 104 , 104 . On the discharge side of the compressors 1A, 1B in the refrigerant circuit A, a check valve 121 is provided. In addition, in the refrigerant circuit A, an electromagnetic on-off valve 122 for controlling the supply of refrigerant to the evaporators 104 and 104 and an electromagnetic on-off valve for controlling the supply of refrigerant to the second subcooling heat exchanger 107 are also provided. valve 123 and lock valve 124 .

As shown in FIG. 2 , the suction lines X of the compressors 1A and 1B are provided with an oil return mechanism Z that preferentially returns the refrigerating machine oil separated from the suction gas refrigerant to the compressor 1A with the smallest capacity. This oil return mechanism Z consists of a substantially horizontal first suction pipe 125 of a fixed length that forms a part of the suction line X and is connected to the compressor 1A with the smallest capacity, and branches from the upper part of the first suction pipe 125 to connect with the capacity. The second suction piping 126 connected to the large compressor 1B is constituted.

In addition, the oil return passage 117 from the oil separator 116 is connected to the first suction pipe 125 .

That is, the refrigerant circuit A has a distribution mechanism R that returns the refrigerating machine oil to the compressors 1A and 1B. The distribution mechanism R distributes the refrigerating machine oil in the refrigerant circulating in the refrigerant circuit A to the respective compressors 1A, 1B according to the different capacities of the respective compressors 1A, 1B. The distributing mechanism R of this embodiment returns the refrigerating machine oil in the refrigerant circulating in the refrigerant circuit A to the compressor 1A in accordance with the principle of distributing from the first compressor 1A with the smallest capacity to the other second compressors 1B. , 1B.

Specifically, the distribution mechanism R has the oil equalizing pipe 109 , an oil separator 116 , an oil return channel 117 and an oil return mechanism Z. Furthermore, the distribution mechanism R may return the refrigerating machine oil separated in the oil separator 116 and the refrigerating machine oil contained in the suction gas refrigerant of the compressors 1A and 1B to the compressor 1A having the smallest capacity preferentially.

With this configuration, when the compressors 1A, 1B are operating, the refrigerating machine oil separated by the oil separator 116 and the refrigerating machine oil in the suction gas refrigerant are returned to the compressor 1A having the smallest capacity. Then, the refrigerating machine oil flows back from the first compressor 1A to the second compressor 1B whose dome chamber internal pressure is lower due to the internal pressure difference of the dome chamber (internal pressure of compressor 1A>internal pressure of compressor 1B). . Therefore, it is possible to secure the refrigerating machine oil for the compressors 1A and 1B without performing the oil equalization operation control for the alternate operation of the compressors as conventionally done.

In addition, in the first suction pipe 125, due to the difference in specific gravity between the refrigerator oil and the gas refrigerant, the refrigerator oil F is separated and flows into the bottom of the pipe. Machine 1A. Therefore, since it is easy to change the piping structure, the refrigerator oil in the compressors 1A, 1B can be secured efficiently at low cost.

Since the oil return passage 117 is connected to the first suction pipe 125, the refrigerating machine oil separated by the oil separator 116 merges with the refrigerating machine oil separated from the suction gas refrigerant in the first suction pipe 125, and returns to the first suction pipe 125. 1 compressor 1A, there is no need to change the structure of the compressor 1A (such as the casing structure, etc.). In addition, the oil return passage 117 may be directly connected to the first compressor 1A.

Second Embodiment

Fig. 3 shows a portion of a suction line in a refrigerating apparatus according to a second embodiment of the present invention.

Among them, the refrigeration device has three compressors 1A, 1B, and 1C each having a different capacity. The upper part of the first suction pipe 125 connected to the first compressor 1A is connected to the second compressor 2B and the second compressor 1C through the second suction pipes 126 , 126 , respectively. The other structures and their functions and effects are the same as those of the first embodiment, so descriptions thereof are omitted.

3rd embodiment

Fig. 4 shows a portion of a suction line in a refrigerating apparatus according to a third embodiment of the present invention.

Wherein, the oil return mechanism X includes: a vertical pipe 127 that forms a part of the suction line X and has an open lower end downward; a pipe body 128 facing the lower part of the vertical pipe 127 and having a horizontal cross-sectional area larger than the vertical pipe 127; A first suction pipe 125 connected to the lower end of the pipe body 128 and connected to the first compressor 1A with the smallest capacity; and a second suction pipe 126 connected to the side wall of the pipe body 128 and connected to the second compressor 1B .

In this way, the suction gas refrigerant flowing into the pipe body 128 from the vertical pipe 127 rapidly expands in the pipe body 128, so that the refrigerator oil is separated from the suction gas refrigerant, and the separated refrigerator oil passes through the first stage by gravity and inertia. The suction pipe 125 returns to the compressor 1A. As a result, since changing the piping structure is simple, the refrigerating machine oil in the compressors 1A, 1B can be secured efficiently at low cost.

In addition, the suction gas refrigerant is sucked in accordance with the suction pressure of the compressors 1A, 1B. In this case, three or more compressors can also be installed. The other structures and their functions and effects are the same as those of the first embodiment, so descriptions thereof are omitted.

Fourth Embodiment

Fig. 5 shows a portion of a suction line in a refrigerating apparatus according to a fourth embodiment of the present invention.

At this time, the oil return mechanism X includes: a horizontal large-diameter pipe 129 that constitutes a part of the suction line X and has a vertical cross-sectional area larger than X in the suction line; it is connected to the pipe wall of the horizontal large-diameter pipe 129 and connected to the first pipe with the smallest capacity. A first suction pipe 125 connected to the compressor 1A; and a second suction pipe 126 concentrically facing the center of the horizontal large-diameter pipe 129 and connected to the second compressor 1B.

In this way, as shown in the flow velocity distribution Y, since the flow velocity of the suction gas refrigerant flowing in the horizontal large-diameter tube 129 can be eased, an annular flow of the refrigerating machine oil is generated on the side of the tube wall where the flow velocity is slow, and the refrigerating machine oil and the suction gas are separated. The refrigerant is separated, and the separated refrigerating machine oil passes through the first suction pipe 125 and returns to the first compressor 1A with the smallest capacity. As a result, since changing the piping structure is simple, the refrigerating machine oil in the compressors 1A, 1B can be secured efficiently at low cost.

In addition, the suction gas refrigerant is sucked in accordance with the suction pressure of the compressors 1A, 1B. In this case, three or more compressors may be installed. The other structures and their functions and effects are the same as those of the first embodiment, so descriptions thereof are omitted.

Fifth Embodiment

6 and 7 show a refrigerant piping system of a refrigeration device according to a fifth embodiment of the present invention.

As shown in FIG. 6 , this refrigeration device has a circuit A for heat pump air conditioning and a refrigerant circuit B for refrigeration. The structure of the refrigerant circuit A for the heat pump air conditioner is that a pair of compressors 1A and 1B with different capacities, a four-way switching valve 2, a heat source side with an outdoor fan 11, and a pair of parallel-connected compressors 1A and 1B, each having a different capacity, are sequentially connected through refrigerant piping. The heat exchanger 3, the expansion valve 4 which acts as a decompression mechanism, and the use-side heat exchanger 5 are connected; The downstream side of 4 is branched and connected to the suction side of the compressors 1A and 1B through the refrigerating evaporator 6 . This refrigeration refrigerant circuit B may also be called a heat recovery circuit.

Among them, the difference from the above-mentioned Embodiment 1 is that the capacity of the first compressor 1A is 5HP, and the capacity of the second compressor 1B is 4HP. In addition, the oil storage part of the first compressor 1A is connected to the oil storage part of the second compressor 1B through an oil equalizing pipe 48 .

Between the heat source side heat exchanger 3 and the expansion valve 4, a storage tank 7 connected to the outlet side part of the heat source side heat exchanger 3 during cooling operation is arranged, and the storage tank 7 is connected with the external heat medium (such as outdoor air). An air-cooled first subcooling heat exchanger 8 for subcooling the liquid refrigerant from the liquid phase part of the storage tank 7 and using the thermal expansion of the subcooling liquid refrigerant from the first subcooling heat exchanger 8 The valve 10 depressurizes the vapor-liquid mixed refrigerant obtained by subcooling the liquid refrigerant portion to further subcool the second subcooling heat exchanger 9 of the triple tube type by latent heat of vaporization. In the second subcooling heat exchanger 9 , the vaporized gas refrigerant is supplied to the suction side of the compressors 1A and 1B through the low-pressure gas piping 12 . The thermosensitive cylinder 10 a of the thermosensitive expansion valve 10 is attached to the low-pressure gas pipe 12 .

The air-conditioning refrigerant circuit A is provided with an electromagnetic on-off valve 13 that does not open only when liquid refrigerant is supplied to the second subcooling heat exchanger 9 . In this embodiment, the heat source side heat exchanger 3 and the first subcooling heat exchanger 8 share the aforementioned outdoor fan 11 .

On the inlet side of said storage tank 7, a bridge circuit 14 with 4 non-return valves 14a-14d is arranged. The bridge circuit 14 functions as a flow path switching mechanism that introduces the liquid refrigerant from the heat source side heat exchanger 3 into the accumulator tank 7 during the cooling operation, and simultaneously passes the liquid refrigerant from the accumulator tank 7 through the expansion valve. 4 and then introduced into the use-side heat exchanger 5; during heating operation, the liquid refrigerant from the use-side heat exchanger 5 is introduced into the gas storage pipe 7, and at the same time, the liquid refrigerant from the storage tank 7 is introduced into the heat source through the expansion valve 4 side heat exchanger 3.

In the air-conditioning refrigerant circuit A, there is provided a check valve 15 that allows liquid refrigerant to flow from the heat source side heat exchanger 3 to the storage tank 7 only during cooling operation, and an electromagnetic on-off valve is also provided. 16. The electromagnetic on-off valve 16 is opened during the heating operation to allow the refrigerant to flow from the expansion valve 4 to the use-side heat exchanger 3, and is closed during the heat recovery operation of the heating to allow the refrigerant to flow from the expansion valve 4 to the use-side heat exchanger 3. The expansion valve 4 communicates with the refrigerating evaporator 6 .

In the upstream side liquid pipe 17 of the refrigerating evaporator 6 of the refrigerating refrigerant circuit B, there is installed a refrigerant in the refrigerating refrigerant circuit C described later that exchanges heat with the exhaust gas refrigerant of the refrigerating compressor 18 . The plate heat exchanger 19.

The refrigerating refrigerant circuit C is formed by sequentially connecting the refrigerating compressor 18 , the plate heat exchanger 19 , the thermosensing expansion valve 20 , the refrigerating evaporator 21 , and the accumulator 22 through refrigerant piping.

Between the use-side heat exchanger 5 and the bridging circuit 14, a series circuit 23a consisting of an electromagnetic on-off valve 24 and a one-way valve 25 that allows refrigerant to flow only in cooling operation and an electromagnetic on-off valve are installed. The reversible flow mechanism 23 is composed of the closed valve 26 and the series circuit 23b of the one-way valve 27 which allows the refrigerant to flow only in the heating operation. In addition, the reversible flow mechanism 23 is provided with a capillary tube 28 for liquid discharge that bypasses the electromagnetic on-off valve 26 .

The refrigerant circuit 13 for refrigeration is provided with a bypass circuit 29 that bypasses the evaporator 6 for refrigeration. In this bypass circuit 29, an electromagnetic on-off valve 30 that opens only when the refrigerating evaporator 6 is stopped is installed.

Furthermore, in the refrigerant circuit B for refrigeration, there is provided an electromagnetic on-off valve 31 that is closed only when the evaporator 6 for refrigeration is stopped. In the cooling refrigerant circuit C, there is provided an electromagnetic on-off valve 32 that is closed only when the cooling evaporator 21 is stopped.

Furthermore, an indoor fan 33 is provided on the use-side heat exchanger 5 , a cooling fan 34 is provided on the cooling evaporator 6 , and a cooling fan 35 is provided on the cooling evaporator 21 .

An oil separator 36 for separating lubricating oil contained in the gas refrigerant is provided on the discharge pipe 47 of the compressor 1A, 1B. The lubricating oil separated by the oil separator 36 flows back to the suction pipe 38 of the compressor 1A, 1B through the oil return passage 37 . In this oil return passage 37, there is provided an electromagnetic on-off valve 39 which opens when oil is returned.

Also, on the discharge side of the compressors 1A, 1B, there is provided a pressure sensor 40 functioning as a high-pressure pressure detection device for detecting the discharge pressure of the compressors 1A, 1B, that is, the high pressure. The refrigerating device has a room temperature sensor 41 for detecting the indoor air temperature, and a discharge temperature sensor 42 for detecting the temperature of the refrigerant in the discharge gas is provided on the discharge side of the compressors 1A and 1B. On the suction side, a pressure sensor 43 for detecting the pressure of the suction gas refrigerant is provided. The cooling device has an outside air temperature sensor 44 for detecting the outside air temperature. The air-conditioning refrigerant circuit A and the cooling refrigerant circuit C are provided with shutoff valves 45 and 46 .

In the refrigerating apparatus configured as described above, the following effects can be obtained.

(I) Cooling operation

At this time, the four-way switching valve 2 is switched as shown by the solid line in Figure 6, the electromagnetic on-off valve 13 performs an opening action, the electromagnetic on-off valve 16 performs a closing action, the electromagnetic on-off valve 24 performs an opening action, and the electromagnetic on-off valve 24 performs an opening action. The valve 26 performs a closing action, the electromagnetic on-off valve 30 performs a closing action, the electromagnetic on-off valves 31 and 32 perform an opening action, and the electromagnetic on-off valve 39 performs an opening action.

In the air-conditioning refrigerant circuit A, the gas refrigerant discharged from the compressors 1A and 1B is condensed and liquefied in the heat source side heat exchanger 3 functioning as a condenser, and then sent into the air conditioner through the check valve 15 and the bridge circuit 14 piggy bank7. The liquid refrigerant from the liquid phase portion of the accumulator tank 7 is supercooled after exchanging heat with outdoor air in the first subcooling heat exchanger 8 . If further subcooling is required, that is, when the electromagnetic on-off valve 13 is opened, the subcooled liquid refrigerant from the first subcooling heat exchanger 8 is in the subcooled liquid state in the second subcooling heat exchanger 9. A part of the refrigerant is further subcooled by the latent heat of vaporization of the gas-liquid mixed refrigerant depressurized by the thermosensing expansion valve 10 . The liquid refrigerant is depressurized by the expansion valve 4 and supplied to the use-side heat exchanger 5 for evaporation, and the obtained latent heat of evaporation can be used as a cold and heat source for refrigeration. Then, the refrigerant is returned to the compressors 1A, 1B.

In addition, in the refrigerant circuit B for refrigeration, the refrigerant decompressed by the expansion valve 4 is branched from the refrigerant circuit A for air conditioning, and then supplied to the evaporator 6 for refrigeration through the plate heat exchanger 19 for further processing. Evaporation, the latent heat of evaporation obtained can be used as a cold and heat source for refrigeration. Then, the refrigerant is returned to the compressors 1A, 1B.

In addition, in the refrigerant circuit C for refrigeration, the gas refrigerant discharged from the compressor 18 for refrigeration flows through the liquid pipe 17 in the refrigerant circuit B for refrigeration in the plate heat exchanger 19 that functions as a condenser. The liquid refrigerant is condensed and liquefied after heat exchange. Then, the condensed liquid refrigerant is depressurized by the expansion valve 20 and supplied to the refrigerating evaporator 21 for evaporation, and the obtained latent heat of evaporation can be used as a cold and heat source for freezing. The refrigerant then flows back to the compressor 18 through the accumulator 22 .

But when temperature is higher in the storehouse of refrigeration, refrigeration, for preventing the ventilation of refrigeration, freezing, preferably allow indoor fan 33 low-speed operation.

(Ⅱ) Heating operation

At this time, the four-way switching valve 2 is switched as shown by the dotted line in Figure 6, the electromagnetic on-off valve 13 performs an opening action, the electromagnetic on-off valve 16 performs a closing action, the electromagnetic on-off valve 24 performs a closing action, and the electromagnetic on-off valve 26 makes an opening action, the electromagnetic on-off valve 30 makes a closing action, the electromagnetic on-off valves 31, 32 make an opening action, and the electromagnetic on-off valve 39 makes an opening action.

In the air-conditioning refrigerant circuit A, the gas refrigerant discharged from the compressors 1A and 1B is condensed and liquefied in the use-side heat exchanger 5 functioning as a condenser, and the obtained latent heat of condensation can be used as a heating heat source. Then, the liquid refrigerant is sent into the storage tank 7 through the one-way valve 15 and the bridge circuit 14, and the liquid refrigerant from the liquid phase part of the storage tank 7 is heated with the outdoor air in the first subcooling heat exchanger 8. Exchanged and supercooled. If further subcooling is required, that is, when the electromagnetic on-off valve 13 is opened, the subcooled liquid refrigerant from the first subcooling heat exchanger 8 is in the subcooled liquid state in the second subcooling heat exchanger 9. One part of the refrigerant is further subcooled by utilizing the latent heat of vaporization of the gas-liquid mixed refrigerant depressurized by the thermosensing expansion valve 10 . Then, the liquid refrigerant is decompressed by the expansion valve 4 and supplied to the evaporator 6 for evaporation through the plate heat exchanger 19 in the refrigerant circuit B for refrigeration, and the obtained latent heat of evaporation can be used as a cold and heat source for refrigeration. Then, the refrigerant is returned to the compressors 1A, 1B.

In addition, in the refrigerant circuit C for refrigeration, the gas refrigerant discharged from the compressor 18 for refrigeration passes through the liquid pipe 17 in the refrigerant circuit B for refrigeration in the plate heat exchanger 19 that functions as a condenser. The liquid refrigerant is condensed and liquefied after heat exchange. Then, the liquid refrigerant is depressurized by the expansion valve 20 and supplied to the refrigerating evaporator 21 for evaporation, and the obtained latent heat of evaporation can be used as a cold and heat source for freezing. The refrigerant then flows back to the compressor 18 through the accumulator 22 .

As described above, in the present embodiment, waste heat used as a cold heat source for refrigeration in the evaporator 6 of the refrigerant circuit B for refrigeration during heating operation can be recovered as a heating heat source in the use-side heat exchanger 5 . At this time, one of the compressors 1A and 1B is stopped. In other words, the capacity of the compressor is reduced.

However, when the heating load is small, that is, when the difference between the set temperature and the room temperature is small, the heat source for refrigeration in the evaporator 6 is somewhat insufficient. To this end, it is only necessary to switch the four-way switch valve 2 to the cooling operation side to perform the refrigeration cycle, and at the same time make the electromagnetic on-off valve 16 open, so that the heat source side heat exchanger 3 can function as a condenser. In addition, in the operation of the refrigeration cycle, once the heating load increases, that is, when the difference between the set temperature and the room temperature increases, as long as the four-way switching valve 2 is switched to the heating operation side to perform the heating cycle, at the same time the electromagnetic The on-off valve 16 makes a closing action, so that the use-side heat exchanger 5 acts as a condenser, and it is sufficient to return to the heating heat recovery operation.

In addition, in the heating operation, when the refrigerating load and the refrigerating load become smaller, in other words, when the suction pressure of the compressors 1A and 1B, that is, the low pressure, decreases, if the air volume of the indoor fan 33 is automatically reduced, the heat on the use side can be reduced. Capacity balance between exchanger 5 and evaporator 6 .

In addition, in the heating operation, when the refrigerating/freezing load becomes small, in other words, when the suction pressure of the compressors 1A and 1B, that is, the low pressure, decreases, the heating heat source in the use-side heat exchanger 5 becomes insufficient. Therefore, It only needs to open the electromagnetic on-off valve 16 to let the heat source side heat exchanger 3 function as an evaporator.

In addition, when the indoor fan 33 stops driving, that is, when the use-side heat exchanger 5 stops running, if the room temperature is lower than a predetermined temperature, the four-way switching valve 2 can also be switched to the heating operation side, and the electromagnetic switch can be turned on and off. The valve 16 is closed, and the heating heat recovery operation is automatically performed.

In this embodiment, as shown in FIG. 7 , the suction pipe 38 is located below the suction ports 50A, 50B of the compressors 1A, 1B. The oil return channel 37 is connected to the suction pipe 38 near the suction port 50A of the first compressor 1A (that is, the compressor with a large capacity), and is arranged on the oil equalizing pipe 48 as the compressor An electromagnetic on-off valve 49 that closes when one of 1A and 1B stops operating. In addition, a filter 51 is provided in the oil return passage 37 .

As shown in FIG. 3 , the compressors 1A, 1B and the electromagnetic on-off valves 39 , 40 are opened and closed (ON/OFF). In the figure, O is open and X is closed.

That is, the air-conditioning refrigerant circuit A has a distribution mechanism R for returning the refrigerating machine oil to the compressors 1A and 1B. The distribution mechanism R distributes the refrigerating machine oil in the refrigerant circulating in the air-conditioning refrigerant circuit A to the respective compressors 1A, 1B according to the different capacities of the respective compressors 1A, 1B. The distributing mechanism R of this embodiment returns the refrigerating machine oil to the compressors 1A and 1B in accordance with the principle of distributing the refrigerating machine oil in the refrigerant circulating in the refrigerant circuit A from the compressor 1A with the largest capacity to the other compressors 1B. .

Specifically, the distribution mechanism R has the oil equalizing pipe 48 , the oil separator 36 and the oil return channel 37 . The distribution mechanism R is configured to return the refrigerating machine oil separated by the oil separator 36 and the refrigerating machine oil contained in the suction gas refrigerant of the compressors 1A and 1B preferentially to the first compressor 1A having the largest capacity.

With the above structure, when the compressors 1A, 1B are operated together, the electromagnetic on-off valves 39, 49 are opened together. The refrigerating machine oil F separated by the oil separator 36 returns to the suction pipe 38 through the oil return passage 37, and returns to the compressors 1A and 1B together with the refrigerating machine oil F in the suction gas refrigerant according to the suction pressure.

At this time, most of the refrigerating machine oil F is returned to the first compressor 1A having a large capacity. Moreover, since the internal pressure of the first compressor 1A with a large capacity is greater than that of the second compressor 1B, the refrigerating machine oil F moves to the second compressor 1B with a small capacity through the oil equalizing pipe 48, and can reliably flow back to both compressors 1A. , 1B. Therefore, the refrigerating machine oil F in the compressors 1A and 1B can be ensured without performing the oil equalization operation control for the compressor alternate operation as in the conventional art.

Furthermore, when the compressors 1A and 1B stop operating together, the on-off valve 39 closes and the oil return passage 37 becomes non-communicating, so the refrigerant does not flow from the oil separator 36 to the suction side when the operation stops.

In addition, when one of the compressors 1A and 1B is stopped, the on-off valve 49 is closed, and the refrigerating machine oil F passing through the oil equalizing pipe 48 does not move. As a result, the movement of the refrigerating machine oil F from the compressor in operation to the compressor in the stopped state is inhibited, so that the refrigerating machine oil F shortage does not occur in the compressor in operation.

In addition, since the suction pipe 38 connecting the compressors 1A, 1B is located below the suction ports 50A, 50B of the compressors 1A, 1B, when the compressor 1A with a large capacity stops operating and the compressor 1B with a small capacity operates, Refrigerator oil F is prevented from flowing into the compressor 1A having a large capacity through the suction pipe 38 .

Embodiment 6

Fig. 9 shows a portion of a suction pipe in a refrigeration device according to a sixth embodiment of the present invention.

In this embodiment, two oil return passages 37A, 37B are connected near the suction ports 50A, 50B, so that the refrigerating machine oil F separated by the oil separator 36 can be reliably returned to the first compressor 1A and the second compressor 1B. The suction port 50A, 50B. In addition, in the oil return passages 37A, 37B, on-off valves 39A, 39B that are closed when the compressors 1A, 1B stop operating are provided, respectively.

In this way, when the compressors 1A and 1B operate together, the refrigerating machine oil separated by the oil separator 36 passes through the oil return passages 37A and 37B, and returns to the compressors 1A and 1B together with the refrigerating machine oil in the sucked gas refrigerant. The result is more reliable oil return. The other configurations and their functions and effects are the same as those of the fifth embodiment, so descriptions thereof are omitted.

Other implementation forms

In the above-mentioned first, third and fourth embodiments, a refrigerator having two compressors with different capacities has been described. However, the invention is also possible with more than 3 compressors of different capacities. For example, the present invention can also be applied to a refrigerating apparatus having three compressors with capacities of 3HP, 4HP, and 4HP or a refrigerating apparatus having three compressors with capacities of 3HP, 4HP, and 5HP.

Possibility of industrial use

To sum up, the refrigerating device of the present invention is suitable for an air-conditioning device with multiple compressors, especially suitable for multiple compressors with different capacities.

Claims (15)

1. a refrigerating plant has mutually connection and different a plurality of compressors (1A, the 1B of capacity side by side ...) refrigerant loop (A), it is characterized in that,

For the refrigerating machine oil in the cold-producing medium that makes described refrigerant loop (A) circulation according to each compressor (1A, 1B ...) different capabilities to each compressor (1A, 1B ...) distribute, be provided with and make this refrigerating machine oil turn back to compressor (1A, 1B ...) distributor gear (R).

2. a refrigerating plant has mutually connection and different a plurality of compressors (1A, the 1B of capacity side by side ...) refrigerant loop (A), it is characterized in that,

For the refrigerating machine oil in the cold-producing medium that makes described refrigerant loop (A) circulation from the compressor (1A) of minimum capacity to other compressor (1B ...) distribute, be provided with and make this refrigerating machine oil turn back to compressor (1A, 1B ...) distributor gear (R) that refluxes.

3. a refrigerating plant has mutually connection and different a plurality of compressors (1A, the 1B of capacity side by side ...) refrigerant loop (A), it is characterized in that,

For the refrigerating machine oil in the cold-producing medium that makes described refrigerant loop (A) circulation from the compressor (1A) of heap(ed) capacity to other compressor (1B ...) distribute, be provided with and make this refrigerating machine oil turn back to compressor (1A, 1B ...) distributor gear (R).

4. refrigerating plant as claimed in claim 2 is characterized in that, described compressor (1A, 1B ...) be low pressure dome chamber type compressor,

Described distributor gear (R) has and compressor (1A, 1B ...) oil equalizing pipe (109) that is communicated with and be located at described compressor (1A, 1B ...) discharge side, separate the oil eliminator (116) that the refrigerating machine oil in the discharging refrigerant is used, the refrigerating machine oil and described compressor (1A, the 1B that separate in the described oil eliminator (116) ...) the suction cold-producing medium in the refrigerating machine oil that comprises preferentially turned back to the compressor (1A) of minimum capacity.

5. refrigerating plant as claimed in claim 3 is characterized in that, described compressor (1A, 1B ...) be high pressure dome chamber type compressor,

Described distributor gear (R) has and compressor (1A, 1B ...) oil equalizing pipe (48) that is communicated with and be located at described compressor (1A, 1B ...) discharge side, separate the oil eliminator (36) that the refrigerating machine oil in the discharging refrigerant is used, the refrigerating machine oil and described compressor (1A, the 1B that separate in the described oil eliminator (36) ...) the suction cold-producing medium in the refrigerating machine oil that comprises preferentially turned back to the compressor (1A) of heap(ed) capacity.

6. refrigerating plant, have by refrigerant piping in order with a plurality of low pressure domes chamber type compressor (1A, the 1B of the different capabilities separately of connection parallel with one another ...), heat source side heat exchanger (2), the mechanism of decompressor (3), the refrigerant loop (A) that uses side heat exchanger (4) to be connected

By oil equalizing pipe (9,9 ...) make described compressor (1A 1B) is interconnected, it is characterized in that,

At described compressor (1A, 1B ...) discharge pipe arrangement (15) on, be provided with and separate discharge the oil eliminator (16) that the refrigerating machine oil in the gas refrigerant is used,

At described compressor (1A, 1B ...) suction circuit (X) in, be provided with and will suck the refrigerating machine oil that comprises in the gas refrigerant and preferentially be back to described compressor (1A, 1B ...) in the oil return mechanism (Z) of compressor (1A) of minimum capacity,

And be provided with the refrigerating machine oil after separating in the described oil eliminator (36) is back to described compressor (1A, 1B ...) in the drainback passage (37) of compressor (1A) of minimum capacity.

7. refrigerating plant as claimed in claim 6, it is characterized in that described oil return mechanism (Z) comprising: constitute described suction circuit (X) a part and with described compressor (1A, 1B ...) in the suction pipe arrangement (25) of the slightly horizontal certain-length that connects of the compressor (1A) of minimum capacity; From the 1st suck the top branch of pipe arrangement (25) and respectively with described compressor (1A, 1B) compressor (1A) compressor (1B, the 1C in addition of minimum capacity ...) connect the 2nd suck pipe arrangement (26,26 ...).

8. refrigerating plant as claimed in claim 6 is characterized in that, described oil return mechanism (Z) comprising: constitute the part of described suction circuit (X) and form the open vertical tube (27) in lower end downwards; In the face of the bottom of this vertical tube (27) and horizontal profile sectional area body (28) greater than this vertical tube (27); Be connected with this body (28) lower end and with described compressor (1A, 1B ...) in the compressor (1A) of minimum capacity connect the 1st suck pipe arrangement (25); And be connected with the sidewall of described body (28) and respectively with described compressor (1A, 1B ...) in compressor (1A) compressor (1B, the 1C in addition of minimum capacity ...) the 2nd pipe arrangement (26,26 that connects ...).

9. refrigerating plant as claimed in claim 6 is characterized in that, described oil return mechanism (Z) comprising: the part and the vertical section sectional area that constitute described suction circuit (X) suck the horizontal large diameter pipe (29) of circuit (X) greater than this; Be connected with this horizontal large diameter pipe (29) tube wall and with described compressor (1A, 1B ...) in the compressor (1A) of minimum capacity connect the 1st suck pipe arrangement (25); And with one heart shape ground in the face of the central part of described horizontal large diameter pipe (29) also respectively with described compressor (1A, 1B ...) in compressor (1A) compressor (1B, the 1C in addition of minimum capacity ...) connect the 2nd suck pipe arrangement (26,26 ...).

10. as each described refrigerating plant in the claim 7,8 and 9, it is characterized in that described drainback passage (37) and the described the 1st sucks pipe arrangement (25) and is connected.

11. refrigerating plant, has the refrigerant loop (A) that is connected by in order that each self-capacity of connection parallel with one another is the different a pair of high pressure dome chamber type compressor (1A, 1B) of refrigerant piping, four-port conversion value (2), heat source side heat exchanger (3), the mechanism of decompressor (4) and use side heat exchanger (5)

By oil equalizing pipe (48) described compressor (1A, 1B) is interconnected, it is characterized in that,

On the discharge pipe arrangement (47) of described compressor (1A, 1B), be provided with to separate and discharge the oil eliminator (36) that the refrigerating machine oil in the gas refrigerant is used,

And be provided with the drainback passage (37A) that the refrigerating machine oil after separating in this oil eliminator (36) is back to described compressor (1A, 1B) suction side,

In this drainback passage (37), be provided with the open and close valve (39) of closing when shutting down with described compressor (1A, 1B).

12. refrigerating plant, have by in order that each self-capacity of connection parallel with one another is the different a pair of high pressure dome chamber type compressor (1A, 1B) of refrigerant piping, four-port conversion value (2), heat source side heat exchanger (3), the mechanism of decompressor (4) and use side heat exchanger (5) and connect the refrigerant loop (A) that is connect

By oil equalizing pipe (48) described compressor (1A, 1B) is interconnected, it is characterized in that,

On the discharge pipe arrangement (47) of described compressor (1A, 1B), be provided with to separate and discharge the oil eliminator (36) that the refrigerating machine oil in the gas refrigerant is used,

And be provided with the drainback passage (37A, 37B) that the refrigerating machine oil after separating in this oil eliminator (36) is back to the suction side separately of described compressor (1A, 1B),

In this drainback passage (37A, 37B), be respectively equipped with the open and close valve (39A, 38B) of closing when shutting down together at described compressor (1A, 1B).

13. as each described refrigerating plant in claim 12 and 13, it is characterized in that, on described oil equalizing pipe (48), be provided with certain 1 open and close valve of closing when shutting down (49) in described compressor (1A, 1B).

14. refrigerating plant, has the refrigerant loop (A) that is connected by in order that each self-capacity of connection parallel with one another is the different a pair of high pressure dome chamber type compressor (1A, 1B) of refrigerant piping, four-port conversion value (2), heat source side heat exchanger (3), the mechanism of decompressor (4) and use side heat exchanger (5)

By oil equalizing pipe (48) described compressor (1A, 1B) is interconnected, it is characterized in that,

On the discharge pipe arrangement (47) of described compressor (1A, 1B), be provided with to separate and discharge the oil eliminator (36) that the refrigerating machine oil in the gas refrigerant is used,

And be provided with the drainback passage (37) that the refrigerating machine oil that will separate in this oil eliminator (36) is back to described compressor (1A, 1B) suction side,

On described oil equalizing pipe (48), be provided with certain 1 open and close valve of closing when shutting down (49) in described compressor (1A, 1B).

15., it is characterized in that the suction line (38) of described compressor (1A, 1B) is positioned at the below of the suction inlet (50A, 50B) of compressor (1A, 1B) as each described refrigerating plant in the claim 11,12 and 14.

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