JP2000088370A - Oil equalizing system for plural compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an oil amount of a compressor to a suitable amount even in the case of different capacities of two compressors of a low pressure shell type. SOLUTION: The oil equalizing system for plural compressors communicates at one end with the vicinity of a standard oil level of a shell of a low capacity side compressor 2 and at the other end with high capacity side suction control tube piping. The system comprises an oil equalizing bypass 5 having a two-way valve 6 on the way of both the ends. The system stops the compressor 2 for a predetermined period when an integrated time of the two compressors arrives at an upper limit integrated time, and opens the valve 6 to prevent an oil amount insufficiency of the compressors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-pressure shell type oil equalizing system for a plurality of compressors.

[0002]

2. Description of the Related Art A conventional oil level control system for an air conditioner equipped with two such low pressure shell type compressors is disclosed in Japanese Utility Model Laid-Open No. 4-11280.

Hereinafter, the oil equalizing system for a plurality of compressors will be described with reference to the drawings.

In FIG. 7, reference numeral 17 denotes a low-pressure shell type compressor, and reference numeral 18 denotes a suction control pipe connected to the compressor. An oil equalizing pipe connection pipe 19 is provided near the standard oil level of the shell of the compressor 17.
Has one end communicating with the oil equalizing pipe 20. When the compressors 17 are distinguished, subscripts a and b are added.

[0005] Next, a method of controlling the oil amount of each compressor in the oil equalizing system of a plurality of compressors having the above configuration will be described.
First, when the oil amount in the shell of the compressor 17 increases and the oil level increases, the pressure of the oil equalizing pipe connection pipe 19 of the compressor 17 increases. Further, when the oil amount in the shell of the compressor 17 decreases and the oil level decreases, the pressure of the oil equalizing pipe connection pipe 19 of the compressor 17 decreases.

Accordingly, for example, when the oil amount of the compressor 17a decreases due to oil forming at the time of starting,
The oil level of the compressor 17a decreases, and the pressure of the oil equalization pipe connection pipe 19a of the compressor 17a becomes lower than the pressure of the oil equalization pipe connection pipe 19b of the compressor 17b. Therefore, the compressor 17b
In the shell of the compressor 17a moves through the oil equalizing pipe 20 into the shell of the compressor 17a, and the shortage of oil in the compressor 17a can be prevented.

When the oil amount of the compressor 17a increases due to uneven return of oil, the height of the oil level of the compressor 17a increases, and the pressure of the oil equalizing pipe connection pipe 19a of the compressor 17a decreases. It becomes higher than the pressure of the oil equalizing pipe connection pipe 19b of the machine 17b. Therefore, the oil in the shell of the compressor 17 is
Through the compressor 17b into the shell of the compressor 17b.
It is possible to prevent an excessive amount of oil of a. Thus, the oil amount of each compressor can be controlled to an appropriate amount.

[0008]

However, in the above configuration, when the two compressors have different capacities,
Alternatively, when one of the compressors is a variable capacity compressor, the pressure in the shell of the high capacity side compressor is low because each compressor is of a low pressure shell type, and the pressure of the low capacity side compressor is low. The pressure in the shell increases.

Therefore, the oil level difference (for example, the differential pressure of 0.01 kg / cm
Until the oil level difference of 10 cm is obtained in step ² ), the oil in the shell of the low-capacity compressor moves through the oil equalizing pipe into the shell of the high-capacity compressor.

[0010] At this time, even if the oil level of the low-capacity compressor is lower than the position of the oil equalizing pipe connecting pipe, the oil stirred by the rotating parts, or Since the oil that has dropped from the compression chamber floats in the form of a mist, the mist-like oil moves to the high-capacity compressor together with the refrigerant.

For this reason, even if the oil level of the low capacity side compressor falls below the position of the oil equalizing pipe connection pipe, the oil amount continues to decrease, and eventually the oil amount becomes insufficient and the compressor is damaged.

As described above, when the two compressors have different capacities, or when one of the compressors is a variable capacity compressor, the low-capacity compressor may have an insufficient oil amount. was there.

As a solution to this problem, a method of stopping all compressors at predetermined time intervals and equalizing oil is conceivable. However, it is necessary to stop all compressors every few minutes. Is not stable. Therefore, there is a problem that the efficiency is lowered and the reliability of the system is lowered.

As another solution, a method of eliminating oil movement between the shells of the compressors without connecting the shells of the compressors with oil equalizing pipes is also conceivable.

However, when the two compressors have different capacities, or when one of the compressors is a variable capacity compressor, the compressor on the higher capacity side has a smaller compression chamber than the compressor on the lower capacity side. Since the amount of oil supplied to the compressor is large, the oil content of the discharged refrigerant is larger than that of the low capacity compressor.

On the other hand, since the oil content of the refrigerant distributed to each compressor via the suction control pipe is equal to each other,
In the high-capacity compressor, the returned oil amount is smaller than the discharged oil amount.

For this reason, if the operation is continued for a long time, the oil amount of the high-capacity compressor continues to decrease, and eventually the oil amount becomes insufficient.
There is a problem that the compressor is damaged.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems, and has as its object to provide an oil equalizing system with a simple configuration when two low pressure shell type compressors are used in parallel.

[0019]

SUMMARY OF THE INVENTION The present invention relates to an air conditioner equipped with two low-pressure shell-type compressors having different capacities, wherein one end is located near the standard oil level of the shell of the low-capacity compressor. The other end communicates with the high-capacity side suction control pipe connected to the high-capacity side compressor, and has an oil equalization bypass with a two-way valve in the middle of both ends. When the time reaches, the low capacity side compressor control means for stopping the low capacity side compressor for a predetermined period, and when the integrated time of the operation of the two compressors reaches the upper limit integrated time, the two-way valve is opened for a predetermined period. A two-way valve control means.

Another aspect of the present invention is an air conditioner equipped with two low-pressure shell type compressors, a variable capacity compressor and a fixed capacity compressor, wherein one end of the standard oil level of the shell of the fixed capacity compressor. An oil equalization bypass having a two-way valve in the middle of both ends communicating with the variable capacity side suction control pipe communicating with the vicinity of the height and the other end connected to the variable capacity compressor. When the time reaches the upper limit integration time, the constant capacity compressor control means for stopping the fixed capacity compressor for a predetermined period, and when the integration time of the operation of the two compressors reaches the upper limit integration time, the two-way valve is operated for a predetermined period. It has two-way valve control means that opens.

Another aspect of the present invention is an air conditioner equipped with two low-pressure shell type compressors, a variable capacity compressor and a fixed capacity compressor, wherein one end of the standard oil level of the shell of the fixed capacity compressor is provided. An oil equalization bypass having a two-way valve in the middle of both ends is provided, and the two compressors are in operation. When the integrated time of the operation in which the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time, the fixed capacity compressor control means for stopping the fixed capacity compressor for a predetermined period, and two compressors are operating. And a two-way valve control means for opening the two-way valve for a predetermined period when the integrated time of the operation in which the variable displacement compressor performs the high capacity operation reaches the upper limit integrated time.

According to the present invention, the amount of oil in the shell of each compressor can be reliably controlled to an appropriate amount in any use condition.

[0023]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is directed to an air conditioner equipped with two low-pressure shell type compressors having different capacities, and one end of which is a standard for a low-capacity compressor shell. Two compressors operating with oil equalization bypass communicating near the oil level, with the other end communicating with the high-capacity suction control pipe connected to the high-capacity compressor, and having a two-way valve at both ends A low-capacity-side compressor control means for stopping the low-capacity-side compressor for a predetermined period when the integrated time of the compressor reaches the upper-limit integrated time; It is provided with a two-way valve control means for opening the valve for a predetermined period.

Therefore, while the two-way valve is closed, the movement of oil from the low-capacity compressor to the high-capacity compressor through the oil equalizing bypass can be prevented. Insufficient quantity can be prevented.

When the integrated time of the operation of the two compressors reaches the upper limit integrated time, the low capacity side compressor is stopped for a predetermined period, the two-way valve is opened, and the oil is bypassed through the oil equalizing bypass. Moves oil from the low-capacity compressor to the high-capacity compressor, thereby preventing the high-capacity compressor from running out of oil because the high-capacity compressor discharges more oil than the low-capacity compressor. it can. At this time, since the fixed capacity compressor is stopped, no mist-like oil floats, and the oil level of the fixed capacity compressor drops below the connection position of the oil equalization bypass, and There is no shortage.

According to a second aspect of the present invention, there is provided an air conditioner equipped with two low-pressure shell-type compressors, a variable capacity compressor and a fixed capacity compressor, and one end of the shell of the fixed capacity compressor. The other end communicates with the vicinity of the standard oil level, and the other end communicates with the variable capacity side suction control pipe connected to the variable capacity compressor,
And equipped with an equalizing bypass with a two-way valve in the middle of both ends,
When the accumulated time of the operation of two compressors reaches the upper limit accumulated time,
A fixed capacity compressor control means for stopping the fixed capacity compressor for a predetermined period; and a two-way valve control means for opening the two-way valve for a predetermined period when the integrated time of the operation of the two compressors reaches the upper limit integrated time. It is provided.

Therefore, even when the variable capacity compressor is operating at a high capacity, the oil can be prevented from moving from the fixed capacity compressor to the variable capacity compressor via the oil equalizing bypass while the two-way valve is closed. In addition, it is possible to prevent a shortage of the oil amount of the fixed capacity compressor.

Further, even when the variable displacement compressor operates at a low capacity, the oil does not move from the variable displacement compressor to the fixed displacement compressor, so that the oil shortage of the variable displacement compressor can be prevented.

When the cumulative time of the operation of the two compressors reaches the upper limit cumulative time, the compressor of a fixed capacity is stopped for a predetermined period, the two-way valve is opened, and the oil is bypassed through the oil equalizing bypass. Since the oil is moved from the fixed capacity compressor to the variable capacity compressor, it is possible to prevent the variable capacity compressor from running out of oil due to the larger discharge oil quantity of the variable capacity compressor during high capacity operation than the fixed capacity compressor. . At this time, since the low-capacity compressor is stopped, no mist-like oil floats, and the oil level of the low-capacity compressor drops below the connection position of the oil equalization bypass. There is no shortage of oil.

According to a third aspect of the present invention, there is provided an air conditioner equipped with two low-pressure shell-type compressors, a variable capacity compressor and a fixed capacity compressor, wherein one end of the compressor has a fixed capacity compressor. The other end communicates with the vicinity of the standard oil level, and the other end communicates with the variable capacity side suction control pipe connected to the variable capacity compressor,
And equipped with an equalizing bypass with a two-way valve in the middle of both ends,
When the two compressors are operating and the integrated time of the operation in which the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time,
A constant capacity compressor control means for stopping the constant capacity compressor for a predetermined period, and an integrated time of an operation in which two compressors are operating and the variable capacity compressor performs a high capacity operation reaches an upper limit integrated time. And a two-way valve control means for opening the two-way valve for a predetermined period.

Therefore, even when the variable capacity compressor is operating at a high capacity, the movement of oil from the fixed capacity compressor to the variable capacity compressor via the oil equalizing bypass can be prevented while the two-way valve is closed. In addition, it is possible to prevent a shortage of the oil amount of the fixed capacity compressor.

Further, even when the variable capacity compressor is operating at a low capacity, oil does not move from the variable capacity compressor to the fixed capacity compressor, so that it is possible to prevent a shortage of oil in the variable capacity compressor.

Further, even when the variable displacement compressor is operating at a low capacity, the oil can be prevented from moving from the variable displacement compressor to the fixed displacement compressor via the oil equalizing bypass while the two-way valve is closed. Insufficient oil amount of the variable displacement compressor can be prevented.

When the integrated time of the operation in which the two compressors are operating and the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time, the fixed capacity compressor is stopped for a predetermined period, and Since the two-way valve is opened and the oil is moved from the fixed capacity compressor to the variable capacity compressor via the oil equalizing bypass, the discharge oil amount of the variable capacity compressor during high capacity operation is reduced to a fixed capacity compression. Insufficient oil quantity of the variable displacement compressor, which is larger than that of the compressor, can be prevented. And at this time, since the fixed capacity compressor is stopped, there is no floating of mist-like oil, and the oil level of the fixed capacity side compressor drops below the connection position of the oil equalizing bypass, There is no shortage of oil.

Further, the fixed capacity compressor is stopped only when the two compressors are operating and the integrated time of the operation in which the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time. The operation time of the machine can be prolonged, and the cooling and heating capacity can be improved.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS.

FIG. 1 is a structural diagram of an oil equalizing system for a plurality of compressors according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a low-pressure shell-type high-capacity compressor, and reference numeral 2 denotes a low-pressure shell-type low-capacity compressor. Reference numeral 3 denotes a high-capacity side suction control pipe connected to the high-capacity side compressor 1, and reference numeral 4 denotes a low-capacity side suction control pipe connected to the low-capacity side compressor 2. Reference numeral 5 has one end communicating with the vicinity of the standard oil level of the shell of the low-capacity compressor 2, the other end communicating with the high-capacity suction control pipe 3, and a two-way valve 6 at both ends. It is a leveling oil bypass.

FIG. 2 is a flowchart showing a control method of the two-way valve 6 of the oil equalizing system for a plurality of compressors according to the first embodiment of the present invention.

As shown in FIG. 2, first, in step 1, the compressor 2
The integrated time Tr of the vehicle operation is detected. In step 2, if the integration time Tr detected in step 1 is shorter than a predetermined upper limit integration time Tro (for example, 3 hours), the process returns to step 1;
Proceed to. In step 3, the two-way valve 6 is opened. In Step 4, the low capacity side compressor 2 is stopped. In step 5, the opening time Tv of the two-way valve 6 is detected.

In step 6, the two-way valve opening time Tv detected in step 5 is equal to a predetermined upper limit two-way valve opening time Tvo.
If it is less than (for example, 2 minutes), the process returns to step 5, and if it is longer than the predetermined upper limit two-way valve opening time Tvo, the process proceeds to step 7. In step 7, the two-way valve 6 is closed. In Step 8, the low capacity compressor 2 is started. In step 9, the integrated time Tr is returned to 0, and the process returns to step 1.

According to this embodiment, when the two-way valve 6 is closed, it is impossible for the oil to move from the low-capacity compressor 2 to the high-capacity compressor 1 via the oil equalizing bypass 5. Absent. Therefore, it is possible to prevent the low-capacity compressor 2 from running out of oil.

When the integrated time of the operation of the two compressors reaches the upper limit integrated time, the low-capacity side compressor 2 is stopped for a predetermined period and the two-way valve 6 is opened, so that the oil equalizing bypass 5 is opened. The oil moves from the low-capacity compressor 2 to the high-capacity compressor 1 via. Therefore, it is possible to prevent a shortage of the oil amount of the high-capacity side compressor 1 because the amount of oil discharged from the high-capacity side compressor 1 is larger than that of the low-capacity side compressor 2. At this time, since the low-capacity side compressor 2 is stopped, no mist-like oil floats, and the oil level of the low-capacity side compressor 2 becomes lower than the connection position of the oil equalizing bypass 5. It does not decrease and there is no shortage of oil.

In this way, it is possible to prevent shortage of the oil amount of each compressor and control the oil amount of each compressor to an appropriate amount.

Embodiment 2 Embodiment 2 of the present invention will be described with reference to FIGS.

FIG. 3 is a structural diagram of an oil equalizing system for a plurality of compressors according to Embodiment 2 of the present invention. In FIG. 3, reference numeral 9 denotes a low-pressure shell type variable displacement compressor, and reference numeral 10 denotes a low-pressure shell type fixed displacement compressor. Reference numeral 11 denotes a variable capacity side suction control pipe connected to the variable capacity compressor 9;
Reference numeral 2 denotes a constant-capacity side suction control pipe connected to the constant-capacity compressor 10. 5 has an end communicating with the vicinity of the standard oil level of the shell of the fixed capacity compressor 10, the other end communicating with the variable capacity side suction control pipe 11, and a two-way valve 6 at both ends. Oil bypass.

FIG. 4 is a flowchart showing a control method of the two-way valve 6 of the oil equalizing system for a plurality of compressors according to the second embodiment of the present invention.

Referring to FIG. 4, first, at step 11, the integrated time Tr of the operation of two compressors is detected. In step 12, if the integration time Tr detected in step 11 is shorter than the predetermined upper limit integration time Tro (for example, 3 hours), the process returns to step 11, and if it is longer than the predetermined upper limit integration time Tro, the process proceeds to step 13. In step 13, the two-way valve 6 is opened. In step 14, the fixed capacity compressor 10 is stopped. In step 15, the opening time Tv of the two-way valve 6 is detected.

In step 16, the two-way valve opening time Tv detected in step 15 is equal to a predetermined upper limit two-way valve opening time Tv.
If it is less than o (for example, 2 minutes), the process returns to step 15,
If it is equal to or longer than the predetermined upper limit two-way valve opening time Tvo, the process proceeds to step S17. In step 17, the two-way valve 6 is closed.
In step 18, the fixed capacity compressor 10 is started. In step 19, the integration time Tr is returned to 0, and in step 1
Return to 1.

According to this embodiment, even when the variable displacement compressor 9 is operating at a high capacity, when the two-way valve 6 is closed, the variable displacement compressor 10 is supplied from the fixed displacement compressor 10 via the oil equalizing bypass 5. No oil moves to the machine 9. Therefore, it is possible to prevent the constant-capacity compressor 10 from running out of oil.

Further, even when the variable displacement compressor 9 is operating at a low capacity, oil does not move from the variable displacement compressor 9 to the fixed displacement compressor 10. Therefore, it is possible to prevent the variable displacement compressor 9 from running out of oil.

When the cumulative time of the operation of the two compressors has reached the upper limit cumulative time, the fixed capacity compressor 10 is stopped for a predetermined period, and the two-way valve 6 is opened so that the oil equalizing bypass 5 is opened. The oil moves from the fixed capacity compressor 10 to the variable capacity compressor 9 via the compressor. Therefore, it is possible to prevent a shortage of the oil amount of the variable displacement compressor 9 because the discharge oil amount of the variable displacement compressor 9 during the high displacement operation is larger than that of the fixed displacement compressor 10.
At this time, since the fixed capacity compressor 10 is stopped, no mist-like oil floats, and the oil level of the fixed capacity compressor 10 drops below the connection position of the oil equalization bypass 5. There is no shortage of oil.

In this way, it is possible to prevent the amount of oil in each compressor from becoming insufficient, and to control the amount of oil in each compressor to an appropriate amount.

(Embodiment 3) Embodiment 3 of the present invention will be described with reference to FIGS.

FIG. 5 is a structural diagram of an oil equalizing system for a plurality of compressors according to Embodiment 3 of the present invention. In FIG. 5, reference numeral 9 denotes a low-pressure shell type variable displacement compressor, and reference numeral 10 denotes a low-pressure shell type fixed displacement compressor. Reference numeral 11 denotes a variable capacity side suction control pipe connected to the variable capacity compressor 9;
Reference numeral 2 denotes a constant-capacity side suction control pipe connected to the constant-capacity compressor 10. 5 has an end communicating with the vicinity of the standard oil level of the shell of the fixed capacity compressor 10, the other end communicating with the variable capacity side suction control pipe 11, and a two-way valve 6 at both ends. Oil bypass.

FIG. 6 is a flowchart showing a control method of the two-way valve 6 of the oil equalizing system for a plurality of compressors according to the third embodiment of the present invention.

As shown in FIG. 6, first, at step 21, the integrated time Th of the operation in which the two compressors are operating and the variable displacement compressor 9 performs the high capacity operation is detected. In step 22, if the integration time Th detected in step 21 is shorter than the predetermined upper limit integration time Tho (for example, 3 hours), the process returns to step 21, and if it is equal to or longer than the predetermined upper limit integration time Tho, the process proceeds to step S23. In step 23, the two-way valve 6 is opened. In step 24, the fixed capacity compressor 10 is stopped. In step 25, the opening time Tv of the two-way valve 6 is detected.

In step 26, the two-way valve opening time Tv detected in step 25 is set to a predetermined upper limit two-way valve opening time Tv.
If it is less than o (for example, 2 minutes), the process returns to step 25,
If it is equal to or longer than the predetermined upper limit two-way valve opening time Tvo, the process proceeds to step S27. In step 27, the two-way valve 6 is closed.
In step 28, the fixed capacity compressor 10 is started. In step 29, the integration time Tr is returned to 0, and in step 2
Return to 1.

According to this embodiment, even when the variable displacement compressor 9 is operating at a high capacity, when the two-way valve 6 is closed, the variable displacement compressor 10 is supplied from the fixed displacement compressor 10 via the oil equalizing bypass 5. No oil moves to the machine 9. Therefore, it is possible to prevent the constant-capacity compressor 10 from running out of oil.

Further, even when the variable displacement compressor 9 is operating at a low capacity, the oil does not move from the variable displacement compressor 9 to the fixed displacement compressor 10. Therefore, it is possible to prevent the variable displacement compressor 9 from running out of oil.

When the two compressors are operating and the integrated time of the operation in which the variable capacity compressor 9 performs the high capacity operation reaches the upper limit integrated time, the fixed capacity compressor 10 is stopped for a predetermined period, Then, by opening the two-way valve 6, the oil moves from the fixed displacement compressor 10 to the variable displacement compressor 9 via the oil equalizing bypass 5. Therefore, it is possible to prevent a shortage of the oil amount of the variable displacement compressor 9 because the discharge oil amount of the variable displacement compressor 9 during the high displacement operation is larger than that of the fixed displacement compressor 10.
At this time, since the fixed capacity compressor 10 is stopped, no mist-like oil floats, and the oil level of the fixed capacity compressor 10 drops below the connection position of the oil equalization bypass 5. There is no shortage of oil.

The fixed capacity compressor 10 is stopped only when the two compressors are operating and the integrated time of the operation in which the variable capacity compressor 9 performs the high capacity operation reaches the upper limit integrated time. The operation time of the capacity compressor 10 can be lengthened, and the cooling and heating capacity can be improved.

In this way, it is possible to prevent the amount of oil in each compressor from becoming insufficient, and to control the amount of oil in each compressor to an appropriate amount.

[0064]

As described above, the invention according to claim 1 is
In an air conditioner equipped with two low-pressure shell-type compressors of different capacities, one end communicates with the low-capacity compressor near the standard oil level of the shell, and the other end connects to the high-capacity compressor. An oil-equalizing bypass communicating with the high-capacity side suction control pipe and having a two-way valve at both ends is provided. The compressor includes a low-capacity side compressor control unit that stops for a period, and a two-way valve control unit that opens the two-way valve for a predetermined period when the integrated time of the operation of the two compressors reaches the upper limit integrated time.

Therefore, while the two-way valve is closed, movement of oil from the low-capacity compressor to the high-capacity compressor via the oil equalizing bypass can be prevented. For this reason, it is possible to prevent a shortage of oil in the low-capacity compressor due to the oil pressure in the low-capacity compressor moving to the high-capacity compressor due to the pressure difference between the shells of each compressor.

When the integrated time of the operation of the two compressors reaches the upper limit integrated time, the low capacity side compressor is stopped for a predetermined period, the two-way valve is opened, and the oil is bypassed through the oil equalizing bypass. Move the oil from the low capacity compressor to the high capacity compressor. For this reason, the high-capacity compressor has a larger oil supply amount to the compression chamber than the low-capacity compressor, and the oil content of the discharged refrigerant is larger than that of the low-capacity compressor. Insufficient quantity can be prevented.

At this time, since the low-capacity side compressor is stopped, there is no floating of mist-like oil that has been agitated by the rotating parts or dropped from the compression chamber. For this reason, the oil level of the low-capacity side compressor does not drop below the connection position of the oil equalizing bypass, and the oil amount does not become insufficient.

In this manner, the shortage of the oil amount of each compressor can be prevented, and the oil amount of each compressor can be controlled to an appropriate amount.

The invention according to claim 2 is an air conditioner equipped with two low-pressure shell-type compressors, a variable capacity compressor and a fixed capacity compressor, and one end of the shell of the fixed capacity compressor. Equipped with two equalizer bypasses, communicating near the standard oil level, with the other end communicating with a variable capacity side suction control pipe connected to the variable capacity compressor, and having a two-way valve in the middle of both ends. When the integration time of the compressor reaches the upper limit integration time, the fixed capacity compressor control means for stopping the fixed capacity compressor for a predetermined period, and when the integration time of the operation of two compressors reaches the upper limit integration time, the two-way valve is activated. It is provided with a two-way valve control means that opens for a predetermined period.

Therefore, even when the variable capacity compressor is operating at a high capacity, the oil can be prevented from moving from the fixed capacity compressor to the variable capacity compressor via the oil equalizing bypass while the two-way valve is closed. For this reason, it is possible to prevent a shortage of the oil amount of the fixed capacity compressor due to the oil pressure of the fixed capacity compressor moving to the variable capacity compressor during the high capacity operation due to the pressure difference between the shells of the compressors.

Also, even when the variable capacity compressor is operating at a low capacity, oil does not move from the variable capacity compressor to the fixed capacity compressor. Therefore, due to the pressure difference between the shells of each compressor,
Insufficient oil amount of the variable displacement compressor due to the movement of the oil of the variable displacement compressor during the low displacement operation to the fixed displacement compressor can be prevented.

When the cumulative time of the operation of the two compressors reaches the upper limit cumulative time, the compressor of a fixed capacity is stopped for a predetermined period, the two-way valve is opened, and the oil is bypassed through the oil equalizing bypass. Move oil from constant capacity compressor to variable capacity compressor. For this reason, the variable displacement compressor during high capacity operation has a larger oil supply amount to the compression chamber than the fixed displacement compressor, and the oil content of the discharged refrigerant is larger than the fixed displacement compressor. Insufficient quantity can be prevented.

At this time, since the fixed-capacity compressor is stopped, no mist-like oil that has been agitated by the rotating parts or that has fallen from the compression chamber floats. For this reason, the oil level height of the fixed capacity compressor does not decrease to the lower side due to the connection position of the oil equalization bypass, and the oil amount does not become insufficient.
In this way, it is possible to prevent shortage of the oil amount of each compressor and control the oil amount of each compressor to an appropriate amount.

Further, the invention according to claim 3 is an air conditioner equipped with two low-pressure shell type compressors, a variable capacity compressor and a fixed capacity compressor, and one end of the shell of the fixed capacity compressor. An oil equalization bypass having a two-way valve in the middle of both ends is provided. The two compressors are connected to the vicinity of the standard oil level, the other end is connected to a variable capacity side suction control pipe connected to the variable capacity compressor, and two compressors are provided. A constant capacity compressor control means for stopping the fixed capacity compressor for a predetermined period when the integrated time of the operation in which the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time, and two compressors Is provided with two-way valve means for opening the two-way valve for a predetermined period when the integrated time of the operation in which the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time.

Therefore, even when the variable displacement compressor is operating at a high capacity, the movement of oil from the fixed displacement compressor to the variable displacement compressor via the oil equalizing bypass can be prevented while the two-way valve is closed. For this reason, it is possible to prevent a shortage of the oil amount of the fixed capacity compressor due to the oil pressure of the fixed capacity compressor moving to the variable capacity compressor during the high capacity operation due to the pressure difference between the shells of the compressors.

Also, even when the variable capacity compressor is operating at a low capacity, oil does not move from the variable capacity compressor to the fixed capacity compressor. Therefore, due to the pressure difference between the shells of each compressor,
Insufficient oil amount of the variable displacement compressor due to the movement of the oil of the variable displacement compressor during the low displacement operation to the fixed displacement compressor can be prevented.

When the integrated time of the operation in which the two compressors are operating and the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time, the fixed capacity compressor is stopped for a predetermined period, and Opening the two-way valve and moving the oil from the fixed displacement compressor to the variable displacement compressor via the oil equalizing bypass. For this reason, the variable displacement compressor during high capacity operation has a larger oil supply amount to the compression chamber than the fixed displacement compressor, and the oil content of the discharged refrigerant is larger than the fixed displacement compressor. Insufficient quantity can be prevented.

At this time, since the low-capacity side compressor is stopped, there is no floating of mist-like oil stirred by the rotating parts or dropped from the compression chamber. For this reason, the oil level height of the fixed capacity compressor does not drop below the connection position of the oil equalizing bypass, and the oil amount does not become insufficient.

Further, the fixed capacity compressor is stopped only when the two compressors are operating and the integrated time of the operation in which the variable capacity compressor performs the high capacity operation reaches the upper limit integrated time. The operation time of the machine can be prolonged, and the cooling and heating capacity can be improved.

In this way, it is possible to prevent the amount of oil in each compressor from being insufficient, and to control the amount of oil in each compressor to an appropriate amount.

[Brief description of the drawings]

FIG. 1 is a structural diagram of an oil equalizing system for a plurality of compressors according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a control method of a two-way valve of the oil equalizing system for a plurality of compressors according to the first embodiment of the present invention.

FIG. 3 is a structural diagram of an oil equalizing system for a plurality of compressors according to a second embodiment of the present invention.

FIG. 4 is a flowchart illustrating a control method of a two-way valve of the oil equalizing system for a plurality of compressors according to the second embodiment of the present invention.

FIG. 5 is a structural diagram of an oil equalizing system for a plurality of compressors according to a third embodiment of the present invention.

FIG. 6 is a flowchart illustrating a control method of a two-way valve of the oil equalizing system for a plurality of compressors according to the third embodiment of the present invention.

FIG. 7 is a structural diagram of a conventional oil equalizing system for a plurality of compressors.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-capacity side compressor 2 Low-capacity side compressor 3 High-capacity side suction control pipe 4 Low-capacity side suction control pipe 5 Equalization oil bypass 6 Two-way valve 7 Low-capacity side compressor control means 8, 14, 16 Two-way valve Control means 9 Variable capacity compressor 10 Constant capacity compressor 11 Variable capacity side suction control pipe 12 Constant capacity side suction control pipe 13, 15 Constant capacity compressor control means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Mitsuo Ogawa 4-5-2-5 Takaida Hondori, Higashi-Osaka City, Osaka Prefecture Matsushita Refrigerating Machinery Co., Ltd. (72) Hiroaki Eguchi 4-chome Takaida Hondori, Higashi Osaka City, Osaka Prefecture No. 2 Matsushita Refrigerator Co., Ltd. (72) Inventor Shunji Moriwaki 4-2-5 Takaida Hondori, Higashi Osaka City, Osaka Prefecture Matsushita Refrigerator Co., Ltd.

Claims (3)

[Claims] 1. An air conditioner equipped with two low-pressure shell type compressors having different capacities, one end of which communicates with the low-capacity compressor near the standard oil level of the shell, and the other end of which has a high capacity. An oil equalizing bypass communicating with the high-capacity side suction control pipe connected to the side compressor and having a two-way valve in the middle of both ends is provided. A low-capacity-side compressor control means for stopping the compressor for a predetermined period; and a two-way valve control means for opening the two-way valve for a predetermined period when the integrated time of the operation of the two compressors reaches the upper limit integrated time. Oil equalization system for multiple compressors. 2. An air conditioner equipped with two low-pressure shell-type compressors, a variable capacity compressor and a fixed capacity compressor, has one end communicating with the shell near the standard oil level of the fixed capacity compressor. , The other end communicates with the variable capacity side suction control pipe connected to the variable capacity compressor, and has an oil equalization bypass with a two-way valve in the middle of both ends, and the integrated time of the operation of two compressors reaches the upper limit integrated time Then, a fixed capacity compressor control means for stopping the fixed capacity compressor for a predetermined period, and a two-way valve control for opening the two-way valve for a predetermined period when the integrated time of the operation of the two compressors reaches the upper limit integrated time. Multi-compressor oil leveling system with means. 3. An air conditioner equipped with two low-pressure shell type compressors, a variable capacity compressor and a fixed capacity compressor, has one end communicating with the shell near the standard oil level of the fixed capacity compressor. An oil equalizing bypass having a two-way valve in the middle of both ends communicating with a variable capacity side suction control pipe connected to the other end of the variable capacity compressor. When the integrated time of the operation for performing the high capacity operation reaches the upper limit integrated time, the fixed capacity compressor control means for stopping the fixed capacity compressor for a predetermined period, the two compressors are operating and the variable capacity compression is performed. An oil equalizing system for a plurality of compressors, comprising: a two-way valve control unit that opens the two-way valve for a predetermined period when an integrated time of an operation in which the machine performs a high-capacity operation reaches an upper limit integrated time.