JPS6157549B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a helium liquefaction device, and particularly to a liquefaction device that can operate stably over a long period of time.

[Technical background of the invention and its problems]

As is well known, in order to operate a superconducting device stably, it is necessary to stably supply liquid helium, which is a refrigerant.

A means for stably obtaining liquid helium, that is, a helium liquefaction device, usually has a structure in which a compressor for compressing helium gas, a heat exchanger type helium liquefaction machine, and a liquid helium container are connected in a closed loop. It is becoming. And recently,
In order to cope with the desire for continuous operation for several years, in particular the moving element of the compressor is subdivided, i.e. the desired number of small compressors are connected in parallel, thereby making it possible to completely shut down the compressor and at any time. This allows us to avoid such situations from occurring.

By the way, since a compressor has movable parts, lubricating oil is usually supplied to these movable parts. If the helium gas is contaminated with such lubricating oil, the performance of the helium liquefaction machine will be extremely reduced and the device will no longer function properly. For this reason, an oil removal filter is generally provided within each compressor.

However, there is no guarantee that the built-in filter will not break down if it is operated continuously for a long period of time, such as several years. If it breaks down, the performance of the helium liquefier will deteriorate due to oil adhesion, and it will take a long time and cost a lot of money to restore the helium liquefier. Therefore, in order to deal with this problem, we have provided a means to detect whether or not oil is mixed in the gas discharge port of each compressor, and with this means we can monitor oil leaks and identify compressors with oil leaks. It is conceivable to separate only one part and repair or replace it.

However, in order to detect oil leaks, it is necessary to continuously release a small amount of helium gas discharged from the compressor into the atmosphere or into a separate container, and to insert a detection filter into this release path. , the more compressors there are, the more helium gas is lost.
Economic disadvantages cannot be avoided.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to minimize the loss of helium gas during operation and without causing oil contamination of the helium liquefaction machine. To provide a helium liquefaction device capable of specifying which compressor among a plurality of compressors is causing an oil leak and replacing or repairing the specified compressor while continuing operation.

[Summary of the invention]

The helium liquefaction device according to the present invention includes a plurality of compressors for helium gas connected in parallel, a helium liquefaction machine, a liquid helium container, and a gas discharge port of the plurality of compressors connected in parallel. Piping that connects to the gas inlets of the plurality of compressors via the helium liquefier and the liquid helium container to form a closed loop, and the gas discharge ports of the plurality of compressors connected in parallel and the helium A plurality of impurity removal filters are inserted in the piping between the liquefier and connected in parallel, and each impurity removal filter is inserted in the gas inflow path and the gas outflow path of these impurity removal filters. A filter connection valve for selectively inserting into the closed loop and selectively separating the filter, and a filter connecting valve for selectively inserting the filter into the closed loop and selectively separating the compressor from the closed loop; a compressor connection valve for insertion and selective separation; a compressor connection valve provided on the discharge path side of the plurality of parallel-connected compressors; monitoring to constantly release a portion of the helium gas through an oil filter that is connected to the piping and is visible from the outside and is located between the impurity removal filter and the filter connection valve provided on the gas inflow path side; and an oil detector for identifying an oil leaking compressor that selectively releases helium gas through an oil filter that is connected to the gas discharge port of each compressor and is visible from the outside. ing.

〔Effect of the invention〕

In the liquefaction equipment described above, impurity removal filters are interposed between the multiple compressors and the helium liquefaction machine, so even if one compressor leaks oil, this leaked oil will be removed. does not migrate to the helium liquefaction machine. Therefore, it is possible to prevent the helium liquefier from being contaminated by the lubricating oil of the compressor. In addition, we constantly monitor whether oil is mixed in the helium gas flowing into the impurity removal filter, and when an oil leak is detected, we sequentially detect oil in the helium gas discharged from each compressor. Since it is possible to check which compressor is causing an oil leak, the amount of helium gas consumed to detect oil contamination can be significantly reduced even if there are a large number of compressors. . Therefore, according to the device of the present invention, oil leakage from the compressor can be detected economically without contaminating the helium liquefaction machine, and as a result,
This can contribute to realizing stable operation of the helium liquefaction device over a long period of time.

[Embodiments of the invention]

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

In the figure, 1a, 1b, 1c and 1d are
A compressor is shown. The gas inlets of these compressors 1a...1d are commonly connected to a pipe 3 via valves 2a...2d, respectively. Further, gas discharge ports of the compressors 1a...1d are commonly connected to a pipe 5 via valves 4a...4d.

The piping 5 is equipped with an impurity removal filter 7a that removes oil, moisture, oxygen, etc. via valves 6a and 6b.
The outlet of impurity removal filters 7a, 7b is connected to the high pressure helium gas inlet of helium liquefier 9 via valves 8a, 8b. The liquid helium discharge port of the helium liquefier 9 is connected to the liquid helium container 1 via piping 10.
It is connected to the inlet of 1. Further, the helium gas outlet of the liquid helium container 11 is connected to the helium gas inlet for heat exchange of the helium liquefier 9 via the pipe 12, and the helium gas outlet for heat exchange of the helium liquefier 9 is connected to It is connected to the pipe 3 via a pipe 13.

Therefore, the piping 5 and the valves 6a, 6b
An oil detector 15 is connected through a valve 14 between the two. This oil detector 15 is composed of a small-diameter discharge pipe that discharges helium gas into the atmosphere or into another container, and an oil filter inserted into this discharge pipe.The oil filter is made visible from the outside. It is composed of On the other hand, each compressor 1
A valve 16 is installed at each gas discharge port of a...1d.
Oil detectors 17a...17d configured similarly to the oil detector described above are connected via a...16d.

According to the present invention, the helium liquefaction apparatus configured as described above is operated as follows. First, valves 1a, 1b...1d, valve 4
a, 4b...4d, valves 6a, 8a and valve 14 are controlled to be open, and valves 16a, 16
b...16d, the valves 6b and 8b are controlled to be closed.

In this state, the compressors 1a, 1b, . . . , 1d are started to operate. These compressors 1a, 1b...1d
The high-pressure helium gas formed by compression is
It is introduced into the helium liquefier 9 through the pipe 5 and the impurity removal filter 7a. The introduced helium gas is liquefied in the helium liquefier 9 and then introduced into the liquid helium container 11 via the pipe 10. Then, the helium gas formed by evaporation in the liquid helium container 11 is transferred to the pipe 1
After passing through the helium liquefier 9 through the helium liquefier 2 and being used for cooling, it is returned to the piping 3 through the piping 13. Therefore, the function of a completely closed-loop helium liquefier is demonstrated here.

Therefore, when the operating state is entered as described above, since the valve 14 is set to be open, a portion of the high pressure helium gas is always passed through the oil detector 15 into the atmosphere or into a special container (not shown). released into the container. Therefore, if oil is leaking from any of the compressors, the oil detector 15 will definitely detect it. Note that even if oil leaks, this oil will be trapped in the impurity removal filter 7a and will not migrate to the helium liquefier 9. As mentioned above, when the oil detector 15 detects the presence of oil, the valve 14 is closed, and the valves 16a, 16b, . . . , 16d are sequentially opened. If such control is performed, an oil leakage reaction will always appear in the oil detector connected to the compressor that is leaking oil. Therefore, you can immediately know which compressor is leaking oil.
This means that while the entire system continues to operate, the compressor that is leaking oil can be isolated and repaired or replaced.

In this way, the oil detector 15 installed at the inlet of the impurity removal filters 7a, 7b detects whether or not oil leaks. The oil detectors 17a, 17b, . . . , 17d provided in the compressors are sequentially operated to make it possible to check which compressor is causing an oil leak. Therefore, the amount of helium gas consumed to detect oil leaks is limited to the amount required to flow through one oil detector. Therefore, the status of each compressor 1a, 1b...1d can be monitored while the amount of helium gas consumed is small and no oil is transferred to the helium liquefier 9, and the above-mentioned effects can be obtained. become. Further, by providing two impurity removal filters in parallel, it is possible to replace or repair one of them while continuing operation.

[Brief explanation of the drawing]

The figure is a block diagram of a helium liquefier according to an embodiment of the present invention. 1a, 1b...1d...compressor, 7a, 7b...
Impurity removal filter, 9... Helium liquefaction machine, 1
1...Liquid helium container, 15, 17a, 17b
...17d...Oil detector.

Claims (1)

[Claims] 1 A plurality of compressors for helium gas connected in parallel, a helium liquefier, a liquid helium container, and a gas discharge port of the plurality of compressors connected in parallel to the helium liquefier and the liquid helium container. piping that connects to the gas inlets of the plurality of compressors to form a closed loop, and the piping between the gas discharge ports of the plurality of compressors connected in parallel and the helium liquefier. A plurality of impurity removal filters are inserted into the closed loop and each impurity removal filter is connected in parallel, and each impurity removal filter is inserted into the gas inflow path and the gas outflow path of these impurity removal filters and selectively inserted into the closed loop. a filter connection valve for selectively separating the compressors from the closed loop; A compressor connection valve for separating the compressors, the compressor connection valve provided on the gas discharge path side of the plurality of parallel-connected compressors, and the plurality of parallel-connected impurity removal filters. At all times, through an oil filter that is connected to the piping and is visible from the outside and is located between the filter connection valve provided on the gas inflow path side,
An oil leakage compressor that selectively releases helium gas through a monitoring oil detector that releases a portion of helium gas and an oil filter that is connected to the gas discharge port of each compressor and is visible from the outside. A helium liquefaction device characterized by comprising a specific oil detector.