JPS6245110Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is applicable to simultaneous parallel operation, regardless of the rotational direction of the first compressor among a plurality of refrigerant compressors pipe-connected in parallel to each other, or when one of the refrigerant compressors The present invention relates to a parallel compressor refrigeration system that maintains the oil level of the compressor at a normal level in either case during one-sided operation.

Conventionally, the device shown in FIG. 1 has been known as this type of device. In FIG. 1, 1 and 2 are semi-hermetic first and second refrigerant compressors;
01 is a crankcase that constitutes the first and second refrigerant compressors 1 and 2, and both crankcases 10
1, 201 is partitioned by partition walls 102, 202 into suction chambers 103, 203 that accommodate motor A, and oil reservoir chambers 104, 204 that accommodate compression element B.

A pressure equalizing hole 1 is located at a predetermined position in the partition wall 102, 202.
05, 205 are provided, and the partition wall 10
An oil level equalizing check valve 106, 206 is installed in an oil level equalizing hole provided at a predetermined position of 2, 202.
These oil equalizing check valves 106, 206 are connected to the suction chamber 103,
The lubricating oil is allowed to flow only from 203 to the oil reservoir chambers 104, 204.

107, 207 are oil splashers for lubricating sliding parts; 3 is a first gas suction pipe connected to the suction chamber 103 of the first refrigerant compressor 1;
It is connected to a suction pipe 5 that connects to an evaporator (not shown) of the refrigeration cycle.

A second gas suction pipe 4 is connected to a suction chamber 203 of the second refrigerant compressor 2 . This second gas suction pipe 4 branches from the upper part of the suction pipe 5.

The gas discharge pipe 6 of the first refrigerant compressor 1 and the gas discharge pipe 7 of the second refrigerant compressor 2 are connected in parallel to a high-pressure pipe 8 connected to a condenser (not shown) of the refrigeration cycle. .

In addition, the oil equalizing hole 108 of the oil reservoir chamber 104 of the first refrigerant compressor 1 and the oil reservoir chamber 204 of the second refrigerant compressor 2
and the oil equalizing hole 208 are connected to each other by an oil equalizing pipe 9. An oil equalizing check valve 10 is provided in the middle of this oil equalizing pipe 9 to allow flow only from the first compressor 1 to the second compressor 2.

Next, the operation will be described. When the first and second refrigerant compressors 1 and 2 are in operation,
Due to the difference in piping resistance between the suction pipes 3 and 4 of the second refrigerant compressors 1 and 2,
The relationship of the operating pressures of the refrigerant compressors 2 is (pressure in the suction chamber 103 of the first refrigerant compressor 1) - (pressure in the suction chamber 203 of the second refrigerant compressor 2) = about 100 to 400 mm
It is now Aq.

Normally, the oil containing about 0.5% of the refrigerant circulation amount returns to the first and second refrigerant compressors 1 and 2 together with the refrigerant gas that has evaporated inside the suction pipe 5 of the refrigeration cycle.

At this time, the refrigerant gas is separated into lubricating oil and gas by the separation means, and most of this oil flows into the first refrigerant gas suction pipe 3 of the first refrigerant compressor 1 under the influence of gravity. Suction chamber 10 of first refrigerant compressor 1
3. The oil passes through the oil equalizing check valve 106 and is supplied to the oil reservoir chamber 104.

The oil is supplied to the oil reservoir chambers 104, 204 of the first and second refrigerant compressors 1, 2 whose pressure is equalized by the pressure equalizing oil pipe 9, and to the suction chambers of the first and second refrigerant compressors 1, 2. As mentioned above, there is a pressure difference between 103 and 203, so the gas flows from the oil sump chamber 104 of the first refrigerant compressor 1 to the oil sump chamber 204 of the second refrigerant compressor 2. The oil is supplied to the oil reservoir chamber 204 of the second refrigerant compressor 2 through the pressure oil pipe 9 and the oil equalizing check valve 10, and can perform its lubrication function normally.

Next, when only the first refrigerant compressor 1 is operated, the refrigerant gas and oil flow into the suction chamber 103 from the suction pipe 5 through the suction pipe 3 of the first refrigerant compressor 1.
During this time, the pressure in the suction chamber 103 of the first refrigerant compressor 1 decreases by about 40 mmAq due to pressure loss in the piping.

On the other hand, since the oil equalizing pipe 9 is provided with an oil equalizing check valve 10 that operates at approximately 100 mmAq, gas flows from the second refrigerant compressor 2 to the oil reservoir chamber 104 of the first refrigerant compressor 1. The pressure in the oil reservoir chamber 104 is maintained at approximately the same level as that in the suction chamber 103 by the action of the pressure equalizing differential valve 105.

Therefore, the oil returned to the suction chamber 103 can be sent to the oil reservoir chamber 104, and even if the first refrigerant compressor 1 is operated continuously, the oil level can be kept relatively stable. Can be done.

Next, when only the second refrigerant compressor 2 is operated, the refrigerant gas is transferred from the suction pipe 5 to the second refrigerant compressor 2.
It flows into the suction chamber 203 through the suction pipe 4 . During this time, the pressure will drop by approximately 600mmAq due to pressure loss in the piping. In addition, the pressure in the oil reservoir chamber 204 is also
It decreases due to the action of 05.

On the other hand, oil is supplied from the suction pipe 5 to the first refrigerant compressor 1
The oil flows into the oil reservoir chamber 104 through the suction pipe 3, the suction chamber 103, and the oil equalization check valve 106, but since the first refrigerant compressor 1 is not operating, the pressure loss in the suction pipe 3 is extremely small. Therefore, the pressure P104 of the oil reservoir chamber 104 of the first refrigerant compressor 1 and the second refrigerant compressor 2
The pressure P204 in the oil reservoir chamber 204 is P104>P2
04, and the oil reservoir chamber 104 of the first refrigerant compressor 1
Due to the pressure difference, a part of the oil accumulated in the second refrigerant compressor 2 is supplied to the oil sump chamber 204 of the second refrigerant compressor 2, allowing normal operation.

However, the oil equalizing holes 108 and 208 are normally located in the first and second holes as shown in FIG. 2 when the compressor motor rotates in the normal direction and as shown in FIG.
In a refrigeration system in which the first refrigerant compressor 1 is lubricated by an oil splasher 107, which is located on the side when viewed from the crank bearing support portion of the refrigerant compressors 1 and 2,
If there is an oil equalizing hole 108 on the side of the first refrigeration compressor 1 on which the oil level rises due to the rotation of the oil splasher 107, the oil level rises due to the rotation of the oil splasher 107 of the first refrigerant compressor 1. , the oil returned to the oil reservoir chamber 104 of the first refrigerant compressor 1 flows through the oil equalizing hole 10.
8, through the oil equalizing pipe 9, the oil equalizing check valve 10, and the oil equalizing hole 208 of the second refrigerant compressor 2, and then passing through the oil equalizing hole 208 of the second refrigerant compressor 2.
A large amount of oil moves into the oil sump chamber 204 of the refrigerant compressor during operation, and the oil level of the refrigerant compressor tends to become unbalanced during operation, making it difficult to check the oil level position from the oil window during maintenance, making maintenance work difficult. It was hot.

In addition, as the oil level of the first refrigerant compressor 1 decreases, lubricant oil may not be supplied to the sliding parts of the refrigerant compressor, and the first refrigerant compressor 1 may seize or
The oil level in the second refrigerant compressor 2 rose abnormally, and there was a risk that the refrigerating capacity would be reduced due to an excessive amount of oil coming up in the refrigerant compressor during operation, and that the valve portion would be damaged due to oil compression.

This invention was made in order to eliminate the above-mentioned conventional drawbacks, and allows flow only from the first refrigerant compressor to the second refrigerant compressor while connecting the oil reservoir chambers of both refrigerant compressors. A connecting pipe in which the oil equalizing hole is located on the first refrigerant compressor side of the oil equalizing pipe provided with a check valve so that the oil equalizing hole is located below the rotation center of the crankshaft of the first refrigerant compressor. By installing the oil sprayer, regardless of the direction of rotation,
An object of the present invention is to provide a parallel compressor refrigeration system that can maintain a normal oil level in a refrigerant compressor.

An embodiment of the parallel compressor refrigeration system of this invention will be described below with reference to FIG. FIG. 4 is an enlarged sectional view of the vicinity of the pressure equalizing oil pipe 9. In FIG. 4, the oil equalizing hole 108' of the first refrigerant compressor 1 is provided below the center of rotation of the crankshaft, which is not affected by the rotational direction of the oil splasher 107 on the connecting pipe 9'.

In addition, this connecting pipe 9' is connected to the oil equalizing pipe 9 and the bolt 11.
They are connected by a flange 12 using a flange 12. This oil equalizing pipe 9 has an oil equalizing check valve 10 that allows flow only from the first refrigerant compressor 1 to the second refrigerant compressor 2, as in the conventional case.

The rest of the structure is the same as the conventional example. however,
When the oil equalizing hole 108' on the connecting pipe 9' is located at the tip of the connecting pipe 9', the oil splasher 10
Since it is strongly affected by the flow of oil caused by the rotation of the connecting pipe 9', the tip of the connecting pipe 9' must be sealed and an oil equalizing hole 108' must be made in the side of the connecting pipe 9' as shown in Fig. 4. No.

Next, the operation will be explained with reference to FIGS. 5 and 6. FIG. 5 shows the compressor motor in normal rotation, and FIG. 6 shows the compressor motor in reverse rotation. The oil equalizing hole 108' of the first refrigerant compressor 1 is provided below the rotation center of the crankshaft, and the oil level position of the oil equalizing hole 108' is always constant regardless of the rotational direction of the oil splash 107. Moreover, the oil level position is approximately the average of all oil levels, and the oil returned to the oil reservoir chamber 104 of the first refrigerant compressor 1 is more than necessary in the oil equalizing hole 10.
8. The oil passes through the connecting pipe 9', the oil equalizing pipe 9, the oil equalizing check valve 10, and the oil equalizing hole 208 of the second refrigerant compressor 2, without moving to the oil reservoir chamber 204 of the second refrigerant compressor 2. This improves the oil level balance of the refrigerant compressor during operation.

This allows the oil window to accurately determine the oil level position during maintenance, making maintenance work easier.

In addition, due to an abnormal drop in the oil level of the refrigerant compressor,
Failure to supply lubricating oil to the sliding parts of the compressor may cause the refrigerant compressor to seize, or the oil level in the refrigerant compressor may rise abnormally, resulting in a decrease in refrigeration capacity due to an excessive amount of oil coming up from the compressor during operation. Also, there is no risk of damage to the valve part due to oil compression.

As described above, according to the parallel compression type refrigeration system of this invention, the oil equalizing hole is set on the center line of the crankshaft at the end of the oil equalizing pipe connecting both refrigerant compressors on the side of the refrigerant compressor with a large capacity. Therefore, while actively returning oil from the refrigeration cycle to one compressor, the oil level in both compressors is maintained at an appropriate level under all conditions, including full operation of both refrigerant compressors and partial operation of either compressor. This makes it possible to prevent seizure of sliding parts, reduction in refrigeration capacity due to excessive oil flow, and damage to valve parts, unlike conventional methods, and it is possible to prevent damage to valve parts regardless of the rotation direction of the compression motor. It is possible to secure the amount of oil.

[Brief explanation of the drawing]

Figure 1 is an oil equalization piping diagram of a conventional parallel compression type refrigeration system, and Figures 2 and 3 are piping diagrams showing cases where the rotation direction of the compressor motor is forward and reverse, respectively, in a conventional parallel compression type refrigeration system. , FIG. 4 is an oil equalization piping diagram of an embodiment of the parallel compressor refrigeration system of this invention, and FIGS. It is a piping diagram showing the reverse case. 1...First refrigerant compressor, 2...Second refrigerant compressor, 103,203...Suction chamber, 104,20
4... Oil reservoir chamber, 107, 208... Oil splasher, 108, 108', 208... Oil equalizing hole,
9... Oil equalizing pipe, 9'... Connection pipe, 10... Oil equalizing check valve. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An oil equalizing check valve that allows oil to flow only from the suction chamber side to the oil sump chamber side is installed at a predetermined position on the partition wall that divides the inside of the crankcase into the suction chamber side and the oil sump chamber side. first and second refrigerant compressors that perform oil lubrication and are connected in parallel to each other by piping; a first refrigerant compressor that is connected to the suction chamber of the first refrigerant compressor and connected to the lower part of the suction pipe of the refrigeration cycle; a second refrigerant gas suction pipe connected to the suction chamber of the second refrigerant compressor and connected to the upper part of the suction pipe of the refrigerant cycle; a refrigerant gas suction pipe of the first and second refrigerant compressors; an oil equalizing pipe that connects the oil reservoir chambers and has an oil equalizing check valve in the middle that allows oil to flow only from the first refrigerant compressor to the second refrigerant compressor; the first refrigerant compressor 1; It has an oil equalizing hole under the center of rotation of the crank, and a connecting pipe connected to the oil equalizing pipe to suck oil in the oil reservoir chamber of the first refrigerant compressor and send it to the second refrigerant compressor. Parallel compression refrigeration equipment.