JPS6135459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling control method for a liquefaction refrigerator such as a helium liquefaction machine or a refrigerator.

In conventional liquefaction refrigerators, the flow rate and pressure of the expansion flow are manually adjusted to control the generation of refrigeration due to the expansion rate, so it is necessary to adjust them each time according to load fluctuations.

The present invention attempts to control the cooling of a liquefaction refrigerator by controlling the expansion flow so that the J-T stream hot end temperature of the heat exchanger on the lowest temperature side is always constant.

An example of implementing the present invention will be described below with reference to the drawings. The feed gas stream 18 and the low-pressure gas stream 17 are pressurized to a specified pressure in the circulation compressor 1 to become a high-pressure gas stream 14, which is cooled by exchanging heat with the low-pressure gas stream 17 in the first heat exchanger 8. At the outlet of the vessel 8, the flow is divided into a J-T stream 16 and an expanded stream 15. The expanded flow 15 passes through the control valve 2, expands to a predetermined pressure in the first expander 3 to generate cold, passes through the third heat exchanger 10, and further expands in the second expander 4 to generate cold. , joins the low-pressure gas stream 17 at the warm end of the fifth heat exchanger 12 . On the other hand, the J-T stream 16 is cooled by exchanging heat with the low pressure gas stream 17 in the second heat exchanger 9, the third heat exchanger 10, the fourth heat exchanger 11, and the fifth heat exchanger 12,
A portion of the liquid is liquefied at the J-T valve 6 due to the Joel-Thomson effect, and the liquid is accumulated in the intermediate tank 13.
The unliquefied gas returns to the circulation compressor 1 as a low pressure gas stream. The liquid in the intermediate tank 13 is drawn out through the liquid drain valve 7 as a product stream 19. Note that the pressure of the high-pressure gas flow 14 is controlled by a pressure regulating valve 2.
This is done by 0. Further, the regulating valve 2 is controlled by a temperature indicating controller 5 (hereinafter referred to as TIC).

The amount of the product stream 19 is determined by the temperature difference between the warm end temperatures T1 and T2 of the fifth heat exchanger 12 and the amount of the J-T stream 16. Therefore, the regulation of the cooling of the entire device is the fifth step.
What is necessary is just to adjust the temperature difference between the hot end temperatures T1 and T2 of the heat exchanger 12 and the J-T flow 16. That is, if the product flow 19 needs to be small, the J-T valve 6 can be squeezed, but if the J-T valve 6 is simply squeezed, the expanded flow 15 will remain the same as before, so the J-T valve 6 can be squeezed.
The ratio of the T flow 16 and the low pressure gas flow 17 increases, the hot end temperature T1 of the fifth heat exchanger 12 decreases, and T2 and T
1 becomes smaller, the liquefaction rate at the J-T valve 6 increases, and the J-T flow 16 decreases.
However, since the liquefaction rate increases, the product stream 19 remains largely unchanged and extra refrigeration occurs. In this case, by operating the TIC 5, the control valve 2 can be controlled to reduce the low pressure gas flow 17, that is, the expansion flow 15, by the amount that the J-T flow 16 has decreased, and the fifth heat exchanger The temperature difference between the hot end temperature T2 and T1 of the vessel 12 can be maintained at all times. J-T flow 16 of high pressure gas flow 14, expansion flow 1
The amount reduced by 5 is returned to the circulation compressor 1 through the pressure control valve 20. In addition, when increasing the product flow 19 contrary to the above, the J-T valve 6
By opening, the flow control valve 2 is also opened, and the high pressure gas flow 14 is appropriately divided into a J-T flow 16 and an expansion flow 15.

Since the present invention is as described above, the cooling balance in the liquefaction refrigerator is J-
It can be automatically adjusted simply by adjusting the T valve, and highly accurate control can be performed.

[Brief explanation of the drawing]

The drawing is a system diagram showing an example of an apparatus implementing the present invention. 1... Circulating compressor, 2... Flow control valve, 3, 4
...Expansion machine, 5...Temperature indicating controller, 6...J-
T valve, 7... Liquid drain valve, 8... First heat exchanger, 9
...Second heat exchanger, 10...Third heat exchanger, 11
...Fourth heat exchanger, 12...Fifth heat exchanger, 13
...Intermediate tank, 14...High pressure gas flow, 15...
Expansion flow, 16... J-T flow, 17... Low pressure gas flow, 18... Raw material gas flow, 19... Product flow, 20
...Pressure control valve. 〓〓〓〓

Claims (1)

[Claims] 1 The high-pressure gas flow boosted by the circulation compressor is transferred to the J-T
After cooling the J-T stream through a plurality of heat exchangers, the low-temperature low-pressure gas, which is expanded and liquefied in the J-T valve and separated into gas and liquid, is passed through the plurality of heat exchangers to reduce the temperature. After the recovery, the gas is returned to the circulating compressor, and the expanded flow is passed through the expander to generate refrigeration and then merged with the low-temperature, low-pressure gas. T
A cooling control method for a liquefaction refrigerator characterized by controlling the flow rate of an expansion flow by detecting the temperature of the flow.