JPS6018909B2 - Extremely low temperature automatic adjustment system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an extremely low temperature automatic adjustment system that effectively performs freezing, liquefaction, etc. using low-temperature liquefied gas (hereinafter referred to as cryogen) such as liquid helium, hydrogen, nitrogen, and LNG. be.

In conventional refrigeration machines, such as helium refrigeration and liquefaction machines, the cooling fluid inlet pressure of the high-pressure (10 to 2 atmospheres) Jehl-Thompson valve is adjusted. Temperatures were difficult to obtain, and automated equipment was expensive, bulky, and heavy.

In addition, the temperature distribution of the hollyhock agent in the low-temperature container of the cooling device is not uniform; in general, the liquid phase part has a lower and more uniform temperature than the gas phase part, but the temperature in the gas phase part is higher. It is unstable. This phenomenon becomes more pronounced as the cryogenic container becomes larger.
This was also a factor that made temperature detection equipment expensive and large. In order to solve the above-mentioned drawbacks, the present invention utilizes the phenomenon in which gas condenses and liquefies as the temperature decreases in principle to obtain operating force, and uses this force to cool the flow path area of the cooling fluid. The present invention provides an automatic extremely low temperature adjustment system that automatically detects and controls the average temperature of a required refrigeration temperature space by changing the low pressure side of the fluid.

One embodiment and other modified embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the configuration of one embodiment of the present invention will be explained based on FIGS. 1 and 2. A Joel-Thomson valve 1 is connected to a high-pressure circuit from a refrigerator (not shown), and is connected to a low-temperature container with an insulated structure. The condenser 2 is connected to the condenser 2 provided inside the condenser 10. An automatic temperature adjustment valve 3 is installed at the tip of the condenser 2, and a return circuit 31 branches from a tank 35 constituting the automatic temperature adjustment valve 3, passes through a heat exchanger 6 for preventing heat radiation, and stores low-temperature contents. Vessel 1
It passes through the outside of 1, connects to the low pressure circuit L, and returns to the refrigerator (not shown). In this case, if unnecessary, the heat exchanger 6 for preventing thermal fin radiation may be omitted and connected directly to the low pressure circuit L. The low-temperature inner container 11 is supported inside the low-temperature container 10 by a heat insulating support material (not shown), etc., and a cryogen such as liquid helium is stored inside. It is separated into a gas phase, and a superconducting magnet 7 is provided in the liquid phase. A required freezing temperature space 11a is provided inside the low-temperature inner container 11, and within the freezing temperature space 11a, a perforated plate 9a connected to the condenser 2 by welding or the like forms a lattice in the gas-liquid phase. A gas-liquid heat exchanger 9 is formed in order to make the temperature distribution of the gas-liquid phase uniform. A constriction part 22 is formed near the end of the condenser 2, and a tank 3 is further formed at the end of the constriction part 22.
5 are connected. One end of the tank 35 is formed into a tapered shape, so that an opening/closing control means (for example, a plug) 32, which is also formed in a tapered shape, comes into close contact with the tank 35. plug 3
One end of the bellows 2 is welded to one end of a movable bellows (or a diaphragm, etc.) 33, while the other end of the bellows 33 is welded to a spherical portion of the tank 35, and the inside of the bellows 33 is a fluid passage. 21 and is completely sealed and separated. Furthermore, a compression spring 34 is provided inside the bellows 33, one end of which is in contact with the seat surface of the plug 32, and the other end is in contact with the spherical seat surface of the tank 35. This acts to apply a preload to bring the tapered portion of the tank 35 and the tapered portion of the plug 32 into close contact. A perforated plate 9a forming a gas-liquid heat exchanger 9 is joined to the cylindrical portion of the tank 35 by welding or the like, and the temperature of the tank 36 is maintained at the average gas phase temperature. A branch pipe 31 is provided from the cylindrical part of the tank 35 to circulate the refrigerant to the return low-pressure circuit L or the radiation heat prevention exchanger 6, and a pongee pipe 4 is further branched from the tip of the spherical part of the tank 35 to supply the air at room temperature. It is connected to a thermometer 5 installed in the section. The tank 35 filled with gas has a diameter of 1, for example.
On the 0 side, a fin 37 with a length of 60 mm and a number of small holes 36 with a thickness of 0.5 mm and a diameter of 3 mm on its outer periphery 35a is 5 mm.
It is attached between the ribs. The temperature of this finned tank 35 becomes the same as that of the surroundings, and the gas enclosed therein also reaches that temperature. The pressure to be sealed in the circuit composed of the bellows 33, the pongee tube 4, and the thermometer 5 is determined after determining the pressure at the required freezing temperature. Next, another modified embodiment of the present invention will be described based on FIG.

The difference from the embodiment of the present invention is that instead of the tapered plug 32 shown in FIG. 2, a rectangular screw-shaped opening/closing control means (for example, a plug) 32' is provided. Except for the mechanism for changing the flow path area, the other configurations are as described in the above-described embodiment of the present invention. A high-pressure low-temperature fluid that has been pre-cooled from a high-pressure circuit connected to a refrigerator (not shown) is
After reaching the Thomson valve 1, it undergoes isenthalpic expansion and liquefies.

At this time, the high-pressure low-temperature fluid becomes low pressure, and the temperature further decreases.
While passing through the condenser 2, it exchanges heat with the refrigerant whose temperature has risen due to the effect of the gas-liquid heat exchanger 9 connected to the condenser 2,
The refrigerant is cooled, and the low-temperature fluid in the condenser 2 rises and reaches the constriction section 22. In the constriction section 22, the low temperature fluid in the gas phase is cooled again, and evaporation of the cryogen or pressure increase due to heat intrusion can be prevented. The low-temperature fluid thus reduced in pressure to approximately one atmosphere while exchanging heat with the cryogen reaches the tank 35. The temperature of the tank 35 is maintained at the average vapor phase temperature of the hollyhock agent by the effect of the fins 37 attached around it, and the inside of the bellows 33 becomes a reduced pressure state according to the temperature, resisting the force of the compression spring 34. and move the plug 32 to the left.
The gap between the tapered portions of the tank 35 and the plug 32 is increased to increase the flow of low temperature fluid from the fluid passage 21 to the branch pipe 31. The internal pressure of the bellows 33, which corresponds to the average gas phase temperature, has been adjusted in advance for pressure and temperature, and is connected to the room temperature section with a pongee tube 4, so that the temperature can be directly read by operating the pointer of the thermometer. ing. When the temperature is high, bellow 3
3, the pressure in plug 32 is high, and in cooperation with compression spring 34, plug 32
Push to the right and act to stop the flow of cryogenic fluid. That is, the automatic temperature adjustment valve 3 having this configuration can automatically control the flow path of the low-temperature fluid according to the temperature and adjust the flow rate. In another embodiment of the invention, shown in FIG. 3, the mechanism for actuating plug 32' is the same, but the mechanism adjusts the flow rate by varying the cryogenic fluid flow path length.

The pressure of the gas sealed inside the bellows 33 is reduced as the temperature decreases, and the rectangular screw-shaped plug 32' is moved to the left against the force of the compression spring 34. After the movement, the distance from the entrance of the groove of the square threaded part to the entrance of the branch pipe 31 becomes shorter, and the low temperature fluid becomes easier to flow by that much, and the flow rate increases. That is, the flow rate of the low temperature fluid can be adjusted depending on the temperature. As described above, according to the present invention, by first performing control on the high pressure side on the low pressure side, flow rate control can be performed without increasing control accuracy.
To control the flow rate on the high-pressure side, it is necessary to adjust the valve opening to a specific amount, but since the volume is increasing, flow control on the low-pressure side does not require the same amount of adjustment as the high-pressure side.

Next, since it has a structure that can always maintain the average temperature of the refrigerated temperature space by the effect of the fins provided around the tank, temperature detection can be performed reliably regardless of the size of the cryogenic container. Furthermore, the required refrigerating temperature can be maintained by changing the flow path area or the flow path length since no adjustment of the collected flow rate is required. As shown in the embodiment, this has the advantage that it can be constructed from several parts, and at the same time has the effect that the flow rate can be adjusted automatically.

[Brief explanation of the drawing]

FIG. 1 is a basic diagram of a cryogenic container according to an embodiment of the present invention, FIG. 2 is a sectional view of an automatic extremely low temperature adjustment system showing an enlarged main part of FIG. 1, and FIG. FIG. 7 is a sectional view of an automatic cryogenic temperature adjustment system showing another embodiment of the present invention. 11a... Refrigeration temperature space, 32, 32'...
... Opening/closing control means, 33... Flexible body (bellows, diaphragm, etc.), 35... Tank. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A low-temperature container in which a freezing temperature space is defined; a condenser disposed within the freezing temperature space and connected to a refrigerator at one end via a high-pressure circuit equipped with a Joel-Thomson valve;
a finned tank disposed in the refrigeration temperature space, one part and the other part connected to the other part of the condenser and a branch pipe of the return circuit, respectively; It has an opening/closing control means that changes the flow path area of the cooling liquid flowing from the condenser into the tank in conjunction with a flexible body containing relatively high-pressure gas and a spring,
A cryogenic automatic adjustment system configured to maintain the freezing temperature space at a required freezing temperature.