CN113551078A

CN113551078A - Low-temperature valve driven by temperature control gas

Info

Publication number: CN113551078A
Application number: CN202110937303.6A
Authority: CN
Inventors: 李海波; 李艳锋; 蔡旭东; 代永光
Original assignee: Csic Pride Nanjing Cryogenic Technology Co ltd
Current assignee: Csic Pride Nanjing Cryogenic Technology Co ltd
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2021-10-26

Abstract

The invention discloses a low-temperature valve driven by temperature control gas, which comprises a valve seat (11), a valve rod (10) and a valve needle (12), wherein the tail end of the valve rod (10) is fixed at the front end of a heat insulation block (8), the tail end of the heat insulation block (8) is in contact connection with a metal film or a metal corrugated pipe (6) at the front end of a sealed gas cavity (16), working gas is filled in the cavity of the sealed gas cavity (16), and a heater (18) for heating the working gas and a temperature sensor (17) for monitoring the temperature of the working gas in real time are arranged in the sealed gas cavity (16). The low-temperature valve generates displacement on a metal film or a metal corrugated pipe based on a quantitative gas temperature-pressure relation, and is used for driving a valve rod of the low-temperature valve to realize the opening adjustment of the low-temperature valve; compared with the traditional adjusting device, the gas temperature adjusting device has higher adjusting precision because stepless continuous change can be realized by controlling the gas temperature and adjusting the pressure; and has the advantages of small volume and low cost.

Description

Low-temperature valve driven by temperature control gas

Technical Field

The invention belongs to the technical field of throttling refrigeration and automatic control in a cryostat, and particularly relates to a control technology for realizing high-precision adjustment of the opening of a low-temperature valve by controlling the temperature of gas in a sealed cavity to drive a flexible metal film or a metal corrugated pipe, in particular to a low-temperature valve driven by temperature control gas.

Background

The low-temperature valve is widely applied to a low-temperature thermostat, and the opening degree adjusting precision of the low-temperature valve directly influences the temperature control precision of the thermostat. At present, the opening degree of the low-temperature valve is usually adjusted by driving a valve rod externally, such as manually, pneumatically, electrically and the like. However, the above-mentioned method often requires a large-sized actuator, and it is difficult to achieve high-resolution adjustment for some occasions requiring fine adjustment. The adoption of the traditional adjusting mode is not beneficial to the high-integration compact design of the low-temperature thermostat, and simultaneously does not meet the requirement of high-precision control of the opening of the low-temperature valve.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a low-temperature valve driven by temperature control gas, which can realize fine adjustment of the opening of the valve through gas temperature control and has high adjustment precision.

The invention aims to solve the problems by the following technical scheme:

the tail end of the valve rod is fixed at the front end of a heat insulation block, the tail end of the heat insulation block is in contact connection with a metal film or a metal corrugated pipe at the front end of a sealed gas cavity, working gas is filled in the cavity of the sealed gas cavity, and a heater for heating the working gas and a temperature sensor for monitoring the temperature of the working gas in real time are arranged in the sealed gas cavity.

The closed gas cavity is composed of a heat-conducting metal pipe and a metal film or a metal corrugated pipe for closing an opening at the front end of the heat-conducting metal pipe.

The flexible cold-conducting chain is connected with an external cold source and arranged on the heat-conducting metal pipe forming the closed gas cavity, and the flexible cold-conducting chain auxiliary heater realizes temperature control of working gas in the closed gas cavity.

The sealed gas cavity is internally provided with a heat conducting rod and heat conducting fins, and the heat conducting rod and the heat conducting fins can improve the temperature uniformity of working gas in the sealed gas cavity.

The heater and the temperature sensor are fixed on the heat conducting rod.

The closed gas cavity is positioned in a heat insulation cavity body formed by the heat insulation base, the heat insulation shell and the fixing ring, and the tail end of the valve seat is fixedly arranged in the through hole of the fixing ring.

The tail end of the heat conducting metal pipe forming the closed gas cavity is fixed on the heat insulation base to isolate heat transfer with the outside.

And an insulating guide ring is arranged between the insulating block and the insulating shell and is used for limiting the insulating block to only move along the axial direction of the valve rod.

The front end of the heat conducting metal pipe forming the closed gas cavity, the metal film or the metal corrugated pipe on the front end of the heat conducting metal pipe and the heat insulating block are all positioned in the annular hole of the heat insulating guide ring.

The front end of the heat insulation block is provided with a sealing corrugated pipe surrounding the tail section of the valve rod, and the rear end and the front end of the sealing corrugated pipe are respectively connected with the front end of the heat insulation block and the tail end of the valve seat in a sealing mode.

Compared with the prior art, the invention has the following advantages:

the low-temperature valve generates displacement on a metal film or a metal corrugated pipe based on a quantitative gas temperature-pressure relation, and is used for driving a valve rod of the low-temperature valve to realize the opening adjustment of the low-temperature valve; compared with the traditional adjusting device, the gas temperature adjusting device has higher adjusting precision because stepless continuous change can be realized by controlling the gas temperature adjusting pressure.

The low-temperature valve disclosed by the invention has the advantages that the number of required parts is less, the sensor, the controller and the actuating mechanism are highly integrated at the position of the valve rod, and compared with the traditional manual, electric and pneumatic adjusting devices, the low-temperature valve has smaller volume and lower cost.

Drawings

FIG. 1 is a schematic diagram of a cryogenic valve of the present invention driven by a temperature controlled gas.

Wherein: 1-a thermally insulating base; 2-flexible cold conducting chain; 3, a heat conducting cylinder; 4-a heat conducting rod; 5-heat conducting fins; 6-metal film or metal bellows; 7-adiabatic guide ring; 8-heat-insulating blocks; 9-sealing the bellows; 10-a valve stem; 11-valve seat; 12-a valve needle; 13-a thermally insulating enclosure; 14-a liquid inlet; 15-a liquid outlet; 16-a closed gas chamber; 17-a temperature sensor; 18-a heater; 19-a fixed ring.

Detailed Description

The invention is described in detail below with reference to the drawings and specific examples. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1: a low-temperature valve driven by temperature control gas comprises a closed gas cavity 16 consisting of a heat-conducting metal pipe 3 and a flexible metal film or metal corrugated pipe 6, wherein the cavity of the closed gas cavity 16 is filled with working gas; a heat conducting rod 4 and a heat conducting fin 5 are arranged in the closed gas cavity 16, so that good temperature uniformity of working gas in the cavity is realized, and the adjusting precision is enhanced; the top of heat conduction pole 4 is equipped with temperature sensor 17 and heater 18, and heat conduction tubular metal resonator 3 side is equipped with the flexibility and leads cold chain 2 and connect outside cold source, and heater 18, flexibility lead cold chain 2 and temperature sensor 17 and are used for airtight gas cavity 16's the interior working gas's of cavity temperature control. The temperature change of the working gas in the cavity of the closed gas cavity 16 causes the pressure change to push the flexible metal film or the metal corrugated pipe 6 to generate displacement, and finally the displacement of the valve needle 12 is realized, and the adjusting effect is realized.

In the low-temperature valve, a heat insulation shell 13 and a heat conduction metal pipe 3 are coaxially arranged on a heat insulation base 1 and are connected with a valve seat 11 through a fixing ring 19, so that heat transfer between the valve seat 11 and the heat conduction metal pipe 3 is isolated; the front end of the flexible metal film or the metal corrugated pipe 6 is connected with the tail end of the valve rod 10 with the valve needle 12 by adopting a heat insulation block 8 to insulate heat transfer; an insulating guide ring 7 is arranged between the insulating block 8 and the insulating shell 13 to limit the insulating block 8, the valve needle 12 and the valve rod 10 to move only along the axial direction, so that heat transfer is isolated.

In the low-temperature valve, a valve seat 11 is fixed on a heat insulation shell 13 through a fixing ring 19, a liquid inlet 14 and a liquid outlet 15 are arranged on the valve seat 11, a sealing corrugated pipe 9 is connected with a valve rod 10 and the valve seat 11 in a sealing mode to avoid leakage of low-temperature fluid, a valve needle 12 is positioned at the top of the valve rod 10, and the valve needle 12 achieves an opening degree adjusting function at the liquid inlet 14 through the relative position of the valve needle and the valve seat 11; the stroke of the valve needle 12 is determined by the working gas pressure in the closed gas chamber 16 and the cryogenic fluid pressure at the outlet orifice 15 of the valve seat 11.

The cryovalve of the present invention is placed inside a cryostat in use, in this embodiment helium is used as the working gas in the closed gas chamber 16. And the master control system adjusts the opening of the low-temperature valve according to the liquid inlet temperature and pressure of the low-temperature fluid and the liquid outlet temperature and pressure of the low-temperature fluid. When the opening degree of the low-temperature valve is reduced, the heater 18 heats the heat conducting rod 4, the heat conducting rod 4 transfers heat to helium in the sealed air cavity 16 through the heat conducting fins 5, when the heating power is greater than the cooling power of the flexible cold conducting chain 2, the temperature of the helium rises, the volume expands, the internal pressure of the sealed air cavity 16 rises, the flexible metal film or the metal corrugated pipe 6 is pushed to generate outward displacement, the heat insulating block 8 is further pushed to displace downwards, the valve needle 12 is matched with the valve seat 11 more tightly along with the downward movement, and the valve opening degree is reduced accordingly. The same can be said for the process of increasing the opening of the low temperature valve. When the valve opening is maintained, the heating power of the heater 18 is adjusted to be equal to the cooling power of the flexible cold conducting chain 2, and the helium temperature is maintained to be unchanged.

The heat insulation parts (heat insulation base 1, heat insulation guide ring 7, heat insulation outer shell 13 and heat insulation block 8) in the low-temperature valve of the invention are made of high-strength low-heat conductivity materials such as G10, thin-wall stainless steel and the like. The heat conducting components (the flexible cold conducting chain 2, the heat conducting rod 4 and the heat conducting fins 5) are made of low-temperature high-heat-conductivity materials, such as high-purity oxygen-free copper. The flexible metal film or metal bellows 6 may be made of 0.1mm copper sheet.

The low-temperature valve can be applied to liquid helium throttling and cooling, and can realize the low temperature of 1.5K in a throttling manner when the flow of 4.2K liquid helium is 0-2.2 mg/s.

The low-temperature valve of the invention generates displacement on a metal film or a metal corrugated pipe 6 based on the quantitative gas temperature-pressure relation, and is used for driving a valve rod 10 of the low-temperature valve to realize the opening adjustment of the low-temperature valve; compared with the traditional adjusting device, the gas temperature adjusting device has higher adjusting precision because stepless continuous change can be realized by controlling the gas temperature adjusting pressure.

The above embodiments are only for illustrating the technical ideas of the present invention, and the protection scope of the present invention should not be limited thereby, and all modifications made on the basis of the technical schemes according to the technical ideas proposed by the present invention fall within the protection scope of the present invention, which should be respected and protected; the technology not related to the invention can be realized by the prior art.

Claims

1. A cryogenic valve employing temperature controlled gas actuation, comprising a valve seat (11), a valve stem (10) and a valve needle (12), characterized in that: the tail end of the valve rod (10) is fixed at the front end of the heat insulation block (8), the tail end of the heat insulation block (8) is in contact connection with a metal film or a metal corrugated pipe (6) at the front end of the sealed gas cavity (16), working gas is filled in the cavity of the sealed gas cavity (16), and a heater (18) for heating the working gas and a temperature sensor (17) for monitoring the temperature of the working gas in real time are arranged in the sealed gas cavity (16).

2. The cryogenic valve driven by a temperature controlled gas according to claim 1, wherein: the closed gas cavity (16) is composed of a heat-conducting metal pipe (3) and a metal film or a metal corrugated pipe (6) for closing the front end opening of the heat-conducting metal pipe (3).

3. The cryogenic valve driven by temperature controlled gas according to claim 1 or 2, wherein: a flexible cold conducting chain (2) connected with an external cold source is arranged on a heat conducting metal pipe (3) forming the closed gas cavity (16), and the flexible cold conducting chain (2) is used for assisting a heater (18) to realize the temperature control of the working gas in the closed gas cavity (16).

4. The cryogenic valve driven by temperature controlled gas according to claim 1 or 2, wherein: the sealed gas cavity (16) is internally provided with a heat conducting rod (4), heat conducting fins (5) are arranged on the heat conducting rod (4), and the heat conducting rod (4) and the heat conducting fins (5) can improve the temperature uniformity of working gas in the sealed gas cavity (16).

5. The cryogenic valve driven by temperature controlled gas according to claim 4, wherein: the heater (18) and the temperature sensor (17) are fixed on the heat conducting rod (4).

6. The cryogenic valve driven by a temperature controlled gas according to claim 1, wherein: the closed gas cavity (16) is positioned in a heat insulation cavity formed by the heat insulation base (1), the heat insulation shell (13) and the fixing ring (19), and the tail end of the valve seat (11) is fixedly arranged in a through hole of the fixing ring (19).

7. The cryogenic valve driven by temperature controlled gas according to claim 6, wherein: the tail end of the heat conducting metal pipe (3) forming the closed gas cavity (16) is fixed on the heat insulation base (1).

8. The cryogenic valve driven by temperature controlled gas according to claim 6, wherein: and a heat insulation guide ring (7) is arranged between the heat insulation block (8) and the heat insulation shell (13), and the heat insulation guide ring (7) is used for limiting the heat insulation block (8) to only move along the axial direction of the valve rod (10).

9. The cryogenic valve driven by a temperature controlled gas according to claim 8, wherein: the front end of the heat conducting metal pipe (3) forming the closed gas cavity (16), the metal film or the metal corrugated pipe (6) on the front end of the heat conducting metal pipe (3) and the heat insulation block (8) are all positioned in the annular hole of the heat insulation guide ring (7).

10. The cryogenic valve driven by a temperature controlled gas according to claim 1, wherein: the front end of the heat insulation block (8) is provided with a sealing corrugated pipe (9) surrounding the tail section of the valve rod (10), and the rear end and the front end of the sealing corrugated pipe (9) are respectively connected with the front end of the heat insulation block (8) and the tail end of the valve seat (11) in a sealing mode.