JP4239366B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-type air conditioner provided with a plurality of compressors in an outdoor unit and provided with a plurality of indoor units, and more specifically, according to the operation and stop status of the plurality of compressors. The present invention relates to an oil leveling system that can make the oil level uniform.
[0002]
[Prior art]
A conventional air conditioner forming a refrigerant circuit is, for example, as shown in FIG. In the figure, 21a, 21b are a plurality of compressors connected in parallel, 22 is a four-way valve that switches the flow of refrigerant discharged from the compressors 21a, 21b in accordance with the cooling operation, heating operation, etc., 23 is outdoor heat exchange , 24 is an expansion valve, 25a and 25b are indoor heat exchangers that can be operated simultaneously or arbitrarily, 26a and 26b are electromagnetic valves, and 27 is an accumulator, which are sequentially connected to form a refrigerant circuit. ing.
28 is an oil separation for separating the oil from the refrigerant discharged including the oil discharged from the compressors 21a and 21b.
[0003]
In the above configuration, the refrigerant flows in the direction of the solid arrow during the cooling operation, and flows in the direction of the broken arrow during the heating operation. The discharged refrigerant containing oil discharged from the compressors 21a and 21b is separated by the oil separator 28. When oil accumulates in the lower part of the oil separator 28, the solenoid valve 30 in the middle of the bypass passage 29 is opened, and the oil is returned to the accumulator 27 via the bypass passage 29, and is returned from the indoor heat exchangers 25a and 25b. Along with the returned gas, it is returned to the compressors 21a and 21b.
[0004]
However, in the above configuration, when the compressors are individually operated, the amount of oil returned from the accumulator 27 varies, and the equilibrium value between the compressors cannot be maintained, so that either of the compressors is short of oil. Had the problem of fear.
[0005]
[Problems to be solved by the invention]
In the present invention, in view of the above-described problems, an air conditioner that can secure an appropriate amount of oil necessary for each compressor when a plurality of compressors are operated simultaneously or individually is provided. With the goal.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention sequentially connects a plurality of compressors connected in parallel, a four-way valve, an outdoor heat exchanger, an expansion valve, a plurality of indoor heat exchangers, and an accumulator. In the air conditioner formed by
The plurality of compressors are composed of a first compressor, a second compressor, and a third compressor, between the discharge pipes of the first compressor and the second compressor and the four-way valve. A first oil separator, a first on-off valve, and a second oil separator connected in series, a discharge pipe of the third compressor, the first on-off valve, and a second oil separator A third oil separator and a second on-off valve are connected in series between the connection points of the compressors, the first compressor and the second compressor are connected by an oil equalizing pipe, and the oil equalizing pipe And the oil return pipe of the first oil separator are connected in series via a third on-off valve and a first throttle, the oil return pipe of the second oil separator is branched, and a fourth on-off valve And the second throttle, the fifth on-off valve and the third throttle, connected in series to the respective suction pipes of the first compressor and the third compressor, and the oil of the third oil separator Return tube, A series connection to the suction pipe of the third compressor through the on-off valve and the fourth throttle, and either the first compressor or the second compressor, and the third compressor An oil level sensor for detecting the oil level height of each compressor is provided for each, and the third on-off valve, the second level valve, and the like according to the oil level height of each compressor detected by the oil level sensor. The fourth on-off valve, the fifth on-off valve and the sixth on-off valve are controlled to open and close.
[0007]
Further, the oil level sensor is configured to detect an upper limit value and a lower limit value of the oil level of each compressor.
[0008]
Further, the third on-off valve, the fourth on-off valve, the fifth on-off valve, and the sixth on-off valve are closed when the oil level of each compressor is at the upper limit value and opened at the lower limit value. It is the structure to control.
[0009]
In addition, after the discharge pipes of the first compressor and the second compressor are merged, they are connected to the first oil separator.
[0010]
Moreover, each said compressor was comprised with the different capability compressor.
[0011]
In addition, a check valve is used for the first on-off valve and the second on-off valve.
[0012]
Moreover, it is the structure which used the solenoid valve for said 3rd on-off valve-6th on-off valve.
[0013]
Further, an expansion valve is used for the throttle.
[0014]
Further, the outlet pipe of the accumulator is connected to the suction pipe of each compressor via a distribution pipe.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on examples.
In FIG. 1, 1a, 1b, 1c are a plurality of compressors connected in parallel, 2 is a four-way valve that switches the flow of refrigerant discharged from the compressors 1a, 1b, 1c according to the cooling operation, heating operation, etc. 3 is an outdoor heat exchanger, 4 is an expansion valve, 5a and 5b are indoor heat exchangers that can be operated simultaneously or arbitrarily, 6a and 6b are electromagnetic valves, and 7 is an accumulator, which are connected in sequence to connect a refrigerant circuit It has a formed configuration.
In the present embodiment, the plurality of compressors are low-pressure, different-capacity compressors for constant speed, a large first compressor 1a and a second compressor 1b, and a small third compressor 1c. It consists of and.
[0016]
Between the connection point of the discharge pipes 1a1 and 1b1 of the first compressor 1a and the second compressor 1b and the four-way valve 2, a first oil separator 8a and a first on-off valve 9a are connected in series. A second oil separator 8b is connected, and a third oil separator 8b is connected between a discharge pipe 1c1 of the third compressor 1c and a connection point between the first on-off valve 9a and the second oil separator 8b. The separator 8c and the second on-off valve 9b are connected in series.
[0017]
The first compressor 1a and the second compressor 1b are connected by an oil equalizing pipe 1ab, and the oil equalizing pipe 1ab and the oil return pipe 8a1 of the first oil separator 8a are connected to a third on-off valve 9c and a second on-off valve 9c. Are connected in series via one throttle 10a, branching off the oil return pipe 8b1 of the second oil separator 8b, the fourth on-off valve 9d, the second throttle 10b, the fifth on-off valve 9e and the third Are connected in series to the respective suction pipes 1a2 and 1c2 of the first compressor 1a and the third compressor 1c through the throttle 10c, and the oil return pipe 8c1 of the third oil separator 8c is connected to the sixth The on-off valve 9f and the fourth throttle 10d are connected in series to the suction pipe 1c2 of the third compressor 1c.
[0018]
Either of the first compressor 1a or the second compressor 1b, and the third compressor 1c, the upper limit value and the lower limit value of the oil level of the compressors 1a, 1b, 1c, respectively. Oil level sensors a and b for detecting the height are provided, and the third on-off valve 9c according to the oil level height of the compressors 1a, 1b and 1c detected by the oil level sensors a and b, respectively. The controller 11 controls the opening / closing of the fourth opening / closing valve 9d, the fifth opening / closing valve 9e, and the sixth opening / closing valve 9f.
[0019]
In the above configuration, the refrigerant flows in the direction of the solid arrow during the cooling operation, and flows in the direction of the broken arrow during the heating operation. When the compressors 1a, 1b, 1c are operated, the discharged refrigerant containing oil discharged from the first compressor 1a and the second compressor 1b is the first separator 8a, The refrigerant discharged from the compressor 1c is separated by the third separator 8c, and the refrigerant that has not been separated is separated again by the second separator 8b.
The oil separated by the first separator 8a is returned to the first compressor 1a and the second compressor 1b from the oil return pipe 8a1 via the oil equalizing pipe 1ab, and the third separator The oil separated in 8c is returned to the suction pipe 1c2 of the third compressor 1c through the oil return pipe 8c1.
The oil re-separated by the second separator 8b is returned to the suction pipes 1a2, 1b2, 1c2 of the compressors 1a, 1b, 1c, respectively.
[0020]
The amount of oil returned to the first compressor 1a and the second compressor 1b by the configuration in which the oil sumps of the first compressor 1a and the second compressor 1b are connected by an oil equalizing pipe 1ab. If there is a variation in the oil level, the equilibrium value is maintained through the oil equalizing pipe 1ab.
[0021]
When the oil level height detected by the oil level sensors a and b is the upper limit value, the third on-off valve 9c, the fourth on-off valve 9d, the fifth on-off valve 9e, and the sixth on-off valve 9f are closed. In the case of the lower limit value, the third on-off valve 9c, the fourth on-off valve 9d, the fifth on-off valve 9e, and the sixth on-off valve 9f are opened, and the amount of oil in each compressor 1a, 1b, 1c is opened. Each on-off valve is controlled to be uniform.
[0022]
As described above, when the compressors 1a, 1b, 1c are operated, the discharged refrigerant containing the oil discharged from the compressors 1a, 1b, 1c is the first separator 8a and the second separator 8a. The oil is separated by the three separators 8c, and the corresponding on-off valves 9a and 9b consisting of solenoid valves or check valves are opened, and the refrigerant not separated is completely separated by the second oil separator 8b. The separated oil passes through the suction pipes 1a2, 1b2, and 1c2 via the fourth on-off valve 9d and the fifth on-off valve 9e, and corresponds to the oil level detected by the oil level sensors a and b. Are distributed to the compressors 1a, 1b, 1c.
Further, the oil separated by the first separator 8a and the third separator 8c is compressed in the same manner as described above according to the oil level height detected by the oil level sensors a and b. Sorted back to 1c.
As a result, the discharged refrigerant has a high separation efficiency, and the required amount of oil is ensured according to the operating conditions of the compressors 1a, 1b, 1c, and the air conditioner does not cause a problem of reliability due to lack of oil.
[0023]
【The invention's effect】
As described above, according to the present invention, when each compressor is operated, the discharged refrigerant containing the oil discharged from each compressor is separated by each oil separator, and the corresponding on-off valve is opened. The refrigerant not separated and separated is completely separated by the second oil separator, and the separated oil passes through the third on-off valve, the fourth on-off valve, the fifth on-off valve, and the sixth on-off valve. Then, the oil is sorted and returned through the suction pipes and the oil equalizing pipes according to the oil level of each compressor. For this reason, the discharged refrigerant has a high separation efficiency, and a required amount of oil is ensured according to the operation status of each compressor, so that the air conditioner does not cause a problem of reliability due to insufficient oil in each compressor.
[Brief description of the drawings]
FIG. 1 is a refrigerant circuit diagram of an air conditioner according to the present invention.
FIG. 2 is a refrigerant circuit diagram of an air conditioner according to a conventional example.
[Explanation of symbols]
1a First compressor
1b Second compressor
1c Third compressor
1a1,1b1,1c1 Discharge pipe
1a2,1b2,1c2 Suction pipe 2 Four-way valve 3 Outdoor heat exchanger 4 Expansion valve
5a, 5b Indoor heat exchanger 7 Accumulator
8a 1st oil separator
8b Second oil separator
8c Third oil separator
8a1,8b1,8c1 Oil return pipe
9a First on-off valve
9b Second on-off valve
9c Third on-off valve
9d 4th on-off valve
9e Fifth open / close valve
9f Sixth on-off valve
10a, 10b, 10c, 10d Aperture
a, b Oil level sensor
11 Control unit

Claims (9)

In an air conditioner in which a plurality of compressors connected in parallel, a four-way valve, an outdoor heat exchanger, an expansion valve, a plurality of indoor heat exchangers and an accumulator are sequentially connected to form a refrigerant circuit.
The plurality of compressors are composed of a first compressor, a second compressor, and a third compressor, between the discharge pipes of the first compressor and the second compressor and the four-way valve. A first oil separator, a first on-off valve, and a second oil separator connected in series, a discharge pipe of the third compressor, the first on-off valve, and a second oil separator A third oil separator and a second on-off valve are connected in series between the connection points of the compressors, the first compressor and the second compressor are connected by an oil equalizing pipe, and the oil equalizing pipe And the oil return pipe of the first oil separator are connected in series via a third on-off valve and a first throttle, the oil return pipe of the second oil separator is branched, and a fourth on-off valve And the second throttle, the fifth on-off valve and the third throttle, connected in series to the respective suction pipes of the first compressor and the third compressor, and the oil of the third oil separator Return tube, A series connection to the suction pipe of the third compressor through the on-off valve and the fourth throttle, and either the first compressor or the second compressor, and the third compressor An oil level sensor for detecting the oil level height of each compressor is provided for each, and the third on-off valve, the second level valve, and the like according to the oil level height of each compressor detected by the oil level sensor. An air conditioner characterized by controlling opening and closing of the fourth on-off valve, the fifth on-off valve and the sixth on-off valve. The air conditioner according to claim 1, wherein the oil level sensor detects an upper limit value and a lower limit value of an oil level of each compressor. Each of the third on-off valve, the fourth on-off valve, the fifth on-off valve and the sixth on-off valve is controlled to be closed when the oil level of each compressor is at the upper limit value and open at the lower limit value. The air conditioner according to claim 1 or 2, characterized by comprising: The air conditioner according to claim 1, wherein the discharge pipes of the first compressor and the second compressor are merged and then connected to the first oil separator. The air conditioner according to claim 1, wherein each of the compressors is constituted by a compressor having a different capacity. The air conditioner according to claim 1, wherein a check valve is used for the first on-off valve and the second on-off valve. The air conditioner according to any one of claims 1 to 4, wherein an electromagnetic valve is used as the third on-off valve to the sixth on-off valve. The air conditioner according to claim 1, wherein an expansion valve is used for the throttle. The air conditioner according to claim 1, wherein an outlet pipe of the accumulator is connected to a suction pipe of each compressor via a distribution pipe.

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