JPS6060465A - Helium liquefying and refrigerating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a helium liquefaction and refrigeration system, and more particularly to fluctuations in refrigeration load due to cooling stoppage of one or more of multiple installed refrigeration load sections and subsequent recooling. The present invention relates to a helium liquefaction/refrigeration system that can maintain a stable operating state without causing excess or deficiency in refrigeration output even if the above conditions occur.

Helium (hereinafter referred to as "He") liquefaction/refrigeration equipment generates cold by isentropically expanding a portion of high-pressure He gas compressed to approximately 15 to 20 atmospheres using one expander. The remainder of the He sludge is precooled step by step to a predetermined low temperature (so-called reversal temperature) by heat exchange, and then passed through a Joule I-Mousson (hereinafter referred to as JT) valve, where it is cooled using the JT effect. By H
The e-waste is liquefied to obtain a liquid He temperature, that is, an extremely low temperature. In this way, if the slicked static He is taken out as a product, it will become a liquefaction device, but on the other hand, the liquid He will be circulated in a closed circuit without being taken out, and the latent heat of the liquid He will be converted into a cryogenic environment. A refrigeration system can be obtained by absorbing the heat load of the object to be cooled in the refrigeration load section and maintaining the temperature of the environment by M1 at -)P.

In other words, the difference between the refrigeration equipment and the liquefaction equipment δ is that in the liquefaction equipment, the gas flow rate on the low pressure side He (return side He) is smaller than the gas flow on the high pressure side He (inlet side He) by the amount of liquefaction. On the other hand, in a refrigeration system, liquefied He also emits A and returns to the low-pressure side, so there is a point where the He gas meteors on the high-pressure side and the low-pressure side become equal. For this reason, the liquefaction equipment and the refrigeration equipment differ in the temperature component je+ of the heat exchanger and expander in the main body of the δ unit, and their thermal designs are different. There isn't. Therefore, the He refrigerating device will be described below as a representative example.

As such a He refrigeration system, one having a configuration as schematically shown in FIG. 1 is known, for example. That is, in FIG. 1, the refrigeration system 1 includes heat exchangers 5a to 5e, expanders 7a and 7b.
, a device main body 2 having a built-in JT valve 6, etc., a compressor 3 and a purifier 4 connected to the population side of the main body 2. It consists of a cryogenic environment section 10 connected to the outlet side of the main body 2 of the device. Then, after the He waste is pressurized by compressor 3 in J,
It descends through the fifth heat exchangers 5a to 5e (hereinafter referred to as the "high-pressure side route") and is cooled while undergoing heat exchange, and is further adiabatically expanded to near atmospheric pressure at the JT valve 6. Partially liquefied He into a gas-liquid mixed state, that is, He mist (
After becoming simply [sometimes referred to as liquid HeJ],
He mist supply! 6 and 8 into the cryogenic environment section 10, and cools the atmosphere of the environment section 10 to a cryogenic temperature. A typical example of a specific use of the cryogenic environment section 10 is a cryogenic fatigue test device for examining the mechanical properties of metal materials at cryogenic temperatures. In this case, if the liquid He in the test device evaporates, it is
It is also possible to provide a condenser for condensing f.

Now, the He gas vaporized by taking away the heat of the object to be cooled existing in the cryogenic environment section 10 is transferred again to the heat exchanger 5a of the apparatus main body 2.
~5e in the opposite direction (hereinafter, the ascending path is referred to as the "low pressure side path"), and after cooling the He flowing in the high pressure side path of the counterflow, it becomes He scum at approximately room temperature and normal pressure. and return to compressor 3. By circulating He through this path, the cryogenic environment 7fl110 is continuously maintained at a cryogenic temperature. In such conventional He refrigerators, the amount of processed products in the expander is manually adjusted and the amount of cold generated by the I-expander is controlled, so if there is a change in load or when starting up, etc. It was necessary to adjust the flow rate each time. In particular, multiple cryogenic environment sections (
In a refrigeration system (hereinafter referred to as Malthusa system) in which multiple users (hereinafter sometimes referred to as "users") are connected in parallel, there are large load fluctuations, and it is necessary to adjust the expander processing oak appropriately.
If this is not done, excessive refrigeration may result in wasted energy. In addition, if a user during cooling operation wants to turn on the cooling of 1), L (or 2 or more units) or start cooling again, it is necessary to perform these operations.
Therefore, the operating conditions of the He refrigeration system fluctuate, and conventional manual operation requires a high level of skill in order to maintain the user's temperature conditions constant during the cooling operation.

The present invention has been made with attention to these circumstances, and it is possible to maintain the user's environmental temperature constant while suppressing the generation of excessive cold in one expander, and furthermore, in a multi-user system, it is possible to keep the user's environment constant. He is such that it is possible to properly stop cooling and recool the user of the original L) without adversely affecting the operating conditions of other users.
The aim is to provide liquefaction/refrigeration equipment.

Thus, the He liquefaction/refrigeration system of the present invention, which has achieved the above objectives, pre-cools He scum at room temperature and high pressure in stages by a heat exchange action that utilizes the cold obtained by isenthalpic expansion of He scum, and then Liquefaction H by passing through the valve
In a He liquefaction/refrigeration system designed to generate The gist lies in that the throughput of the expander is controlled in accordance with the above.

The configuration and effects of the present invention will be explained below with reference to the drawings. The drawings are representative examples and do not limit the present invention. Changes in the basic configuration and arrangement of the container, expansion @, etc., or the structure of the cryogenic environment section, etc., as necessary, are all included within the technical scope of the present invention.

FIG. 2 is a schematic overall view showing an embodiment of the He refrigeration system of the present invention, in which 13 shows a temperature control controller, 14 shows a pressure control controller, 15 shows a temperature measurement point, and 16 shows a pressure detection point.

A part of the high-pressure He gas in the system L2 on the He waste discharge side of the compressor 3 is cooled by the expanders 7a and 7b, and the remaining He gas cooled by this cold passes through the JT (F6 and undergoes the JT effect). generates He mist and cools the cryogenic environment.
The O atmosphere is cooled to an extremely low temperature. Here, the He gas G1 υ1 discharged from the expander 7b on the low temperature side and the cryogenic environment section 1
Temperature measurement point 1 is located downstream from the confluence with the return waste G2 from 0.
5 is provided, and the measured temperature value at the temperature measuring point 15 is input to the temperature control controller 13, and the throughput of the low temperature side expander 7b is adjusted according to the level of the measured temperature value. In other words, the temperature value is set to 1+
If it is higher than fi, it means that the amount of cold generated by the expander 7b is insufficient, so the temperature control controller 1
3 sends a command to increase the output to the expander 7b, and the expander 7b
The process increases cold generation (-), thereby lowering the temperature at temperature measurement point 15. On the other hand, if the fllll temperature value is lower than the set value, the amount of cold generation due to expansion @7b is excessive. This means that the temperature control controller 13 sends a command to reduce the output to the expander 7b.
The amount of cold generation is reduced by reducing the processing use of b, thereby increasing the temperature at the temperature measuring point 15. In this way, temperature measurement point 15
temperature is maintained constant. As a result, in the heat exchanger 5d, the high-pressure side He scum, which is cold, is subjected to a stable cooling effect by the low-pressure side He gas, which is a coolant with a constant set temperature, so that the temperature after heat exchange remains at a predetermined temperature. Can maintain temperature. As a result, the cryogenic environment section 10 can be easily maintained at a constant temperature regardless of fluctuations in operating conditions. The temperature measurement point 15 shall be installed between the confluence point and the heat exchanger section 11 (including the inlet) immediately after the confluence point, and
Between temperature point 11 and temperature point 15, there is I of the utilized gas Gl and the return gas G2.
It is also possible to provide a mixer to improve the Xy combination.

However, when the discharge amount of compressor 3 is constant, 1 expander 7
Even if the throughput of b is changed according to the refrigeration load, the required power of the He refrigeration system does not change, and especially when the refrigeration load decreases, the energy consumption rate decreases. In order to prevent this decrease, in the He refrigeration system of the present invention, the discharge pressure of the compressor 3 is detected at the pressure detection point 16, and the discharge amount of the compressor 3 is adjusted by the pressure control controller 14 so as to keep this pressure constant. It is designed to adjust. When the refrigeration load decreases as a result, if only the JT Got is throttled down, the processing ♀ of the expander 7b will also decrease in accordance with the refrigeration load, and the pressure control controller 14 will work to keep the discharge pressure of the compressor 3 constant. By reducing the discharge air volume, it is possible to prevent a decrease in the energy consumption rate and to perform energy-saving operation.

FIG. 3 is a schematic overall diagram showing an example of a recondensing multi-user system according to the present invention, in which users 10e and 1 have recondensers 11e and llf installed in one refrigeration device 2.
Two 0fs are connected. Although the multi-user system according to the present invention includes a system in which many users are connected in parallel, the example in FIG. 3 illustrates a system with two users for ease of understanding.

The room temperature high pressure He supply system L2 on the He discharge side of the compressor 3 is connected to the system L4 leading to the i3% expansion machine and the user 10elTIJT valve 6.
e and user 10fj [JT valve 6f, respectively, are branched into systems Le and Lf, and a stop valve 17e is installed in the room temperature section of each latter system along the flow direction of He.
, 17f and flow-o adjustment cylinder needles +2e, +2f are provided, respectively. The opening of the JT valve is adjusted using the flow controller 12.
e, 12f. and user IO
e, a temperature measurement point 1 downstream from the point where the return gas G1 from 10f and the gas G2 taken out from the low temperature side expander 7b join;
5b, and in this example, a temperature measuring point 15a is also provided downstream from the confluence point of the combined gas G3 and the gas G4 discharged from the high temperature side expander 7a,
Temperature control controller 13b corresponding to 5b and 15a
, 13a is installed. Of course, temperature measurement point +5a
can also be omitted. Also, as in example i'iif, a pressure detection point 16 is provided on the discharge side of the compressor 3, and a pressure control controller 14 corresponding to the pressure detection point 16 is provided.

] - In the multi-user system of 41ft d,
2, (user 1) J, For example, when only user lGf is operated, if +17e is closed, high-pressure He, which is a refrigerant, will no longer be supplied to user foe. Therefore, expansion a7b.

If 7a is processed early or as specified, the amount of cold generated will be excessive,
+! 111 temperature point 15b, +5a or a predetermined temperature (+
Since the sludge ratio decreases, the temperature controllers 13b and 13a operate to bring the temperature down to a predetermined temperature, thereby reducing the throughput of the expanders 7b and 7a. As the predetermined ji of the high-pressure He gas in the He refrigerator decreases due to the above operation, the pressure control controller 14 operates to keep the pressure at the pressure detection point 16 constant, and the multi-user system If some users want to use the system, just close the stomp valve (17e in the example above) for that system, and the cold generation amount and compressor discharge amount will be automatically adjusted, making it easy to always Energy savings can be achieved by operating under optimal conditions.

In addition, when cooling the user 10e to a cryogenic temperature during the cooling operation of the user lof, after pre-cooling the user IOe with liquid nitrogen, the stop valve 17e is gradually opened and chilled He is supplied. Point 15b, +5a
Since the temperature rises, this temperature rise is detected and the temperature control controllers 13b and +3a are operated to control the expansion a.
The throughput of 7b and 7a is increased to increase the cooling of the generating group, and the temperature of temperature measuring points 15b and +5a is maintained at a predetermined value.

Due to the above operation, the predetermined amount of high-pressure He scum in the He refrigerator increases, so the pressure controller 14 operates to adjust the discharge air volume of the compressor 3 so as to keep the pressure at the pressure detection point 16 constant.

]- In a multi-user system, the body 11
- When re-cooling a user inside, simply open the stomp gor (+7e in the above example) of that system gradually, and the amount of cold generated can be reduced without disturbing the normal operation of the other user 10f who is driving. The discharge amount of the compressor is automatically adjusted and recooling can be easily performed.

The present invention is constructed as described above, and the effects summarized below can be obtained.

(1) The amount of cold generated by the expander is increased or decreased to keep it optimal in response to operating conditions such as fluctuations in refrigeration load, so the best operating conditions can be maintained and the temperature of the cryogenic environment section can be maintained at a predetermined value. It is possible to operate with the lowest energy consumption rate while maintaining safety.

(2) In a multi-user system, if one (or two or more) of the multiple users operating the
You can easily restart the system without disturbing the 2V state of other users.

[Brief explanation of drawings]

1 (4 is a schematic overall diagram showing the conventional He freezing device, FIG. 2 is a schematic overall diagram showing the He freezing device according to the unreleased 1),
FIG. 3 is a schematic overall IΔ showing the He refrigerating device of the multi-user system according to the present invention. 2... Refrigeration equipment main body 3... Compressors 5a to 5e...
・Heat exchanger 6...JT valve 7a...High temperature side expander
7b...Low temperature side expander 10...Cryogenic environment section (user) 13, 13a, 13b...Temperature control controller I/roller 14...Pressure control controller +5, +5a, +5b...Temperature measurement Point 16...
・Pressure detection point applicant 41 Science and Technology Agency Director General Accounting Division Figure 1 Luconi Figure 2 Figure 1

Claims (1)

[Claims] (1) After pre-cooling the helium gas at room temperature and high pressure in a stepwise manner by a heat exchange action that utilizes the cold obtained by the isentropy of heliud gas, the helium gas is passed through a Joule-Thomson valve to generate liquefied helium.
In this helium liquefaction/cooling d) equipment, the lowest temperature is determined by the temperature measurement result from the temperature measuring device installed below the confluence of the extruded gas from the expander and the return gas from the cryogenic environment section. 4. The expander is configured to control the throughput in the expander. +j Helium liquefaction/refrigeration system; A1 (2. In the device according to claim 1, the pressure on the discharge side of the compressor for producing helium scum at room temperature and high pressure is detected, and the detected value is constant. A helium liquefaction/refrigeration system configured to control a compressor so that