Device for reducing background leakage rate of large vacuum chamber at high temperature

Abstract

The invention belongs to the technical field of vacuum application, and particularly relates to a device for reducing the background leakage rate of a large vacuum chamber at high temperature. According to the device, a dry pump, a reaction furnace and a liquid nitrogen heat exchanger are installed in a box body, the dry pump is fixedly installed at the bottom in the box body, and the dry pump, the reaction furnace and the liquid nitrogen heat exchanger are connected in parallel through a pipeline; one end of an air inlet extends out of the box body, and the other end of the air inlet is connected with a pipeline of the liquid nitrogen heat exchanger; an air outlet is simultaneously connected with a pipeline of the liquid nitrogen heat exchanger and a pipeline of the reaction furnace; the dry pump is used for exhausting the whole pipeline of a hydrogen removal system to achieve low vacuum; the reaction furnace is used as a gas reaction container, and a getter material is arranged in the reaction furnace; the liquid nitrogen heat exchanger exchanges heat with high-temperature gas from shielding block hot helium leak detection equipment, so that the temperature of the high-temperature gas is reduced. According to the invention, the background leak rate of the large vacuum chamber at high temperature can be effectively reduced, and the detection sensitivity of the whole set of hot helium leak detection test system can be improved, so that stricter leak detection requirements can be met.

Description

technical field [0001] The invention belongs to the technical field of vacuum application, and in particular relates to a device for reducing the background leakage rate of a large vacuum chamber under high temperature. Background technique [0002] Because leakage will cause serious consequences, spacecraft, pressure-bearing parts in fusion reactor vacuum chambers, storage containers / transportation pipelines for toxic, harmful, explosive and radioactive substances, etc., have extremely strict requirements on leakage, so helium leak testing is widely used in petrochemical, It is widely used in nuclear power, aerospace, automobile, packaging and transportation, air conditioning, space stack, power battery and other fields. Among them, the high-temperature shut-off valve of the space station and related pipeline welds, nuclear power fuel cladding tubes, and fusion reactor vacuum chamber components all need high-temperature helium leak detection, while rockets and other spacecr...

AI Technical Summary

Problems solved by technology

Among them, the high-temperature shut-off valve of the space station and related pipeline welds, nuclear power fuel cladding tubes, and fusion reactor vacuum chamber components all need high-temperature helium leak detection, while rockets and other spacecraft, missile bodies and warheads, etc. Faced with high temperatures, nuclear power evaporators (such as heat transfer tubes) and various heat exchanger pipes and valves not only work at high temperatures, but also have high-pressure fluids inside. The above-mentioned components have begun to use cold helium leak detection in recent years, but with The high-temperature or high-pressure environment in actual operation is inconsistent, and the leakage risk of equipment / components under service conditions cannot be evaluated, resulting in huge maintenance and overhaul costs. In the future, the thermal helium leak detection method close to actual working conditions may be used to test the leakage rate of components

[0003] According to research and experiments, the main reason why it is difficult to increase the background leak rate of the vacuum chamber at high temperature is that the surface area of ​​the vacuum chamber is large, resulting in the release of a large amount of surface-adsorbed gas at high temperature. These residual gases contain small molecular gases such as hydrogen and helium. , will form the basic background leak rate caused by non-leakage, which will seriously affect the background leak rate of the vacuum chamber, resulting in the inability to reduce the background leak rate of the helium leak detection equipment and the sensitivity of the detection system. The test results have a greater impact

[0004] Therefore, the main reason why the background leakage rate of the vacuum chamber reaches the bottleneck at high temperature is that the hydrogen released on the surface of the material is large and difficult to remove at high temperature, and the higher the detection temperature requirement, the greater the hydrogen released, and the background of the vacuum chamber The leak rate and system sensitivity will be poorer, making it impossible to meet the thermal helium leak detection needs of a wider range of products

[0005] The vacuum helium leak detection method is a commonly used leak detection method in vacuum applications. At present, the bottleneck restricting high-temperature helium leak detection is mainly that the background leak rate of the vacuum chamber is difficult to reduce at high temperatures, which will affect the sensitivity of the detection system.

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