JPH0686962B2 - refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention has at least two compressors for a low pressure stage and a high pressure stage, and has an oil tank for storing lubricating oil for each compressor. The gas-phase space of the oil tank relates to a refrigerator in which a pressure equalizing pipe communicates with the suction side of the low-pressure stage compressor.

[Conventional example]

FIG. 3 is a diagram showing the configuration of a conventional refrigerator of this type.
As shown, the refrigerator has a low-pressure stage compressor 1 and a high-pressure stage compressor 2, and the low-pressure stage compressor 1 and the high-pressure stage compressor 2 each have an oil tank 11a and an oil tank 11b. The gas-phase spaces 11a and 11b communicate with the suction side of the low-pressure stage compressor 1 through pressure equalizing tubes 12a and 12b. The evaporator 3 is communicated with the suction side of the low-pressure stage compressor 1 through the communication passage 6, and the discharge side of the low-pressure stage compressor 1 and the suction side of the high-pressure stage compressor 2 are communicated with each other through the communication passage 7 to achieve high-pressure stage compression. The discharge side of the machine 2 is connected to the suction side of the condenser 4 by the communication passage 8, and
The discharge side is communicated with the suction side of the evaporator 3 by the communication passage 9a, the throttling mechanism 5, and the communication passage 9b. In the figure, 13 is an evaporator heat transfer tube, and 14 is a condenser heat transfer tube. Further, 15a is an impeller of the low pressure stage compressor 1, and 15b is an impeller of the high pressure stage compressor 2.

In the refrigerator having the above-described configuration, as a means for recovering the lubricating oil that has flowed from the lubricating oil system to the refrigerant system, oil easily accumulates in the low-pressure portion of the compressor, so that the low-pressure stage compressor 1 and the high-pressure stage compressor 2 are Lubricating oil is collected in the oil tanks 11a, 11b of the respective compressors from the downstream of the respective suction vanes 18a, 18b by the ejectors 17a, 17b driven by the discharge gas of the respective compressors.

[Problems to be Solved by the Invention]

However, in the above-described conventional lubricating oil recovery method, since the lubricating oil easily collects on the low pressure stage side, the amount of oil recovery on the low pressure stage side becomes larger than the oil recovery amount on the high pressure stage side, and the low pressure stage compressor is operated by operating for a long time. While the oil level of the oil tank 11a of No. 1 rises, the oil level of the oil tank 11b of the high-pressure compressor 2 decreases, and in an extreme case, the high-pressure compressor 2 runs out of oil,
It had the drawback of not being able to drive.

The present invention has been made in view of the above points, and eliminates the above-mentioned drawbacks, so that the required lubricating oil can be secured even on the high pressure side without the lubricating oil being biased to the low pressure stage oil tank, and stable operation can be performed for a long time. To provide a refrigerator.

[Means for Solving the Problems]

In order to solve the above problems, the present invention has a refrigerator configured as follows. That is, having at least two compressors for the low pressure stage and the high pressure stage,
Each compressor has an oil tank that stores lubricating oil,
In the refrigerator in which the gas phase space of the oil tank communicates with the suction side of the low pressure stage compressor by a pressure equalizing pipe, a high pressure is used as a mechanism for supplying oil from the oil tank of the low pressure stage compressor to the oil tank of the high pressure stage compressor. A bypass path for sending a part of the discharge oil of the ejector or the oil pump of the low-pressure stage compressor to the oil tank chamber of the high-pressure stage compressor, which is operated by using the discharge gas of the stage-stage compression as a driving fluid, and An overflow pipe overflowing above a predetermined liquid level was provided in the oil tank, and the overflowed oil was returned to the oil tank of the low-pressure compressor.

[Action]

By configuring the refrigerator as described above, a mechanism for supplying oil from the oil tank of the low pressure stage compressor to the oil tank of the high pressure stage compressor is provided, and at a predetermined liquid level or higher in the oil tank of the high pressure stage compressor. Since an overflow pipe is provided to return the overflowed oil to the oil tank of the low-pressure stage compressor, the lubricating oil can be secured on the high-pressure stage side without the lubricating oil deviating to the low-pressure stage side oil tank. It enables stable operation for a long time.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a refrigerator that constitutes an embodiment of the present invention. In the same figure, the parts given the same reference numerals as in FIG. 3 indicate the same or corresponding parts (the same applies to other drawings below).

In FIG. 1, the discharge gas is extracted from the communication passage 8 which is the discharge pipe of the high-pressure stage compressor 2 through the passage 21, and the ejector 20
The passage 22 for sucking oil from the oil tank 11a of the low-pressure compressor 1 is connected to the ejector 20, and the sucked oil is transferred to the oil tank 11b of the high-pressure compressor 2 via the passage 23. To configure. Further, the oil tank 11b of the high-pressure stage compressor 2 has another end of an overflow pipe 19 through which oil overflows above a predetermined liquid level.
It is connected to 11a.

With the above configuration, the oil is constantly transferred from the oil tank 11a of the low pressure stage compressor 1 to the oil tank 11b of the high pressure stage compressor 2 by the action of the ejector 20, and the lubrication required for the high pressure stage compressor 2 is required. The amount of oil is secured. Further, when the oil level of the oil tank 11b of the high-pressure compressor 2 rises and reaches the attachment portion of the overflow pipe 19, the oil supplied from the low-pressure compressor 1 thereafter overflows into the overflow pipe 19. The oil that overflows from each oil tank 11a, 11b
Since they are communicated with each other by 2a and 12b, the oil tank 11 of the low pressure stage compressor 1 passes through the overflow pipe 19 due to the difference in liquid level.
Since the oil is returned to a, the oil required for operating the compressor can be secured in both the low-pressure compressor 1 and the high-pressure compressor 2 without the oil all concentrating in the high-pressure compressor 2.

FIG. 2 is a diagram showing the structure of a refrigerator constituting another embodiment of the present invention. In the figure, part of the oil discharged from the oil pump 25 of the low-pressure compressor 1 is sent to the oil tank 11b of the high-pressure compressor 2 through the passage 26. Further, the oil tank 11b of the high-pressure stage compressor 2 is provided with an overflow pipe 19 through which oil overflows above a predetermined liquid level, and the other end of the overflow pipe 19 is connected to the oil tank 11a of the low-pressure stage compressor 1. ing.

With the above configuration, oil is constantly transferred from the oil tank 11a of the low-pressure stage compressor 1 to the oil tank 11b of the high-pressure stage compressor 2 by the oil pump 25, and the lubricating oil required for the high-pressure stage compressor 2 is obtained. The quantity is secured. Further, when the oil level of the oil tank 11b rises and reaches the mounting portion of the overflow pipe 19, the oil supplied from the low pressure stage compressor 1 thereafter overflows into the overflow pipe 19. The overflowed oil is returned to the oil tank 11a of the low-pressure stage compressor 1 through the overflow pipe 19 due to the liquid level difference because the oil tanks 11a and 11b are communicated with each other through the pressure equalizing pipes 12a and 12b. It is possible to secure the amount of oil necessary for operating the compressor in both the low-pressure stage compressor 1 and the high-pressure stage compressor 2 without all the oil being concentrated in the high-pressure stage compressor 2.

〔The invention's effect〕

As described above, according to the present invention, a mechanism for supplying oil from the oil tank of the low-pressure stage compressor to the oil tank of the high-pressure stage compressor is provided, and the oil tank of the high-pressure stage compressor has a predetermined liquid level or higher. An overflow pipe that overflows is installed,
Since the oil that overflowed is returned to the oil tank of the low-pressure stage compressor, the low-pressure stage compressor and the high-pressure stage compressor can secure the lubricating oil necessary for operating the compressor. The excellent effect of increasing the reliability and durability of the machine can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a refrigerator constituting one embodiment of the present invention, FIG. 2 is a diagram showing a configuration of a refrigerator constituting another embodiment of the present invention, and FIG. 3 is a conventional refrigerator of this kind. It is a figure which shows the structure of a refrigerator. In the figure, 1 ... Low pressure stage compressor, 2 ... High pressure stage compressor, 3 ...
… Evaporator, 4 …… Condenser, 5 …… Throttle mechanism, 6,7,8,9a, 9
b, 10a, 10b …… communication passage, 11a, 11b …… oil tank, 12
a, 12b …… pressure equalizing tube, 13 …… evaporator heat transfer tube, 14 …… condenser heat transfer tube, 15a, 15b …… impeller, 17a, 17b …… ejector, 18
a, 18b …… Suction vane, 19 …… Overflow pipe, 20 …… Ejector, 21,22,23 …… Communication passage, 25 …… Oil pump, 26 …… Communication passage.

Claims (3)

[Claims] 1. At least two compressors for a low pressure stage and a high pressure stage are provided, and an oil tank for storing lubricating oil is provided for each compressor, and a vapor phase space of the oil tank is formed by a pressure equalizing pipe. In the refrigerator communicating with the suction side of the low-pressure compressor, a mechanism for supplying oil from the oil tank of the low-pressure compressor to the oil tank of the high-pressure compressor is provided, and the oil tank of the high-pressure compressor is connected to the oil tank. A refrigerator characterized in that an overflow pipe overflowing at a predetermined liquid level or more is provided and the overflowed oil is returned to the oil tank of the low-pressure compressor. 2. An ejector that operates using the discharge gas of the high-pressure compressor as a driving fluid is provided as a mechanism for supplying oil from the oil tank of the low-pressure compressor to the oil tank of the high-pressure compressor. The refrigerator according to claim 1. 3. A mechanism for supplying oil from the oil tank of the low-pressure stage compressor to the oil tank of the high-pressure stage compressor, wherein a part of oil discharged from an oil pump of the low-pressure stage compressor is supplied to the high-pressure stage compressor. The refrigerator according to claim 1, further comprising a bypass route for sending the oil tank chamber.