Helium mass spectrometry leak detection of the hot

2022-09-21
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Helium mass spectrometry leak detection of steel drums

the good or bad air tightness of steel drums directly affects their performance and safety, especially for steel drums that contain special substances (such as polluting substances or toxic substances), which are the skills that must be mastered in the senior engineer examination of cable testing work

bubble leak detection method is an ancient and simple leak detection method, but the tested parts must be launched, which brings trouble to the drying of products, and the volume of steel barrels is generally large, which is not convenient for launching; In addition, bubble leak detection can only rely on visual observation, and the leak detection sensitivity can generally reach pa.m3/s, but the difference is very large, which can no longer meet the precision requirements of products in actual production occasions

at present, many manufacturers have begun to use helium leak detection method. Helium mass spectrometry leak detection is a leak detection method that uses helium as the exploration gas for the leak and uses mass spectrometer to detect the helium overflowing from the leak. It has the advantages of fast reaction speed, high detection accuracy, large detection range, non-toxic, pollution-free, high efficiency, starting the oil pump, no radioactivity and so on

helium leak detection method is generally divided into evacuation method and helium filling method. According to the working condition of the steel barrel, it is generally positive pressure, so helium filling method is adopted for leak detection. Helium filling methods mainly include suction gun method and vacuum box method, that is, after filling the workpiece with helium at the specified pressure, use the suction gun of the leak detector to close to the suspected leak point of the workpiece for suction leak detection, or put the workpiece filled with helium into a vacuum box slightly larger than the workpiece, vacuum the vacuum box through the pump group, and then connect with the leak detector to measure the overall leak rate of the workpiece. The device of suction gun method is relatively simple, but the workpiece is large and easy to be missed, and the accuracy, speed and automation of leak detection are not as good as that of vacuum box method

use the vacuum box method to detect the leakage of the steel barrel. The main process is as follows:

helium filling: fill the steel barrel with helium at the specified pressure. Since the steel barrel can not bear high vacuum and high pressure, a certain amount of helium is directly injected into the barrel quickly. The helium concentration is about the volume of helium injected/the volume in the steel barrel (before helium filling, a certain amount of clean air can be introduced into the steel barrel to eliminate the dirty air in the steel barrel). Seal the steel barrel immediately after filling with helium. Put the steel barrel filled with helium into the vacuum box. After the vacuum box is vacuumized to the specified vacuum degree by the evacuation pump, the leak detector is connected to the vacuum box. If there is a leak in the steel barrel, helium will enter the vacuum box through the leak hole. In addition to measuring the helium signal in the vacuum box by himself, the leak detector is unqualified if the leak rate exceeds the set value. When using the vacuum box method for leak detection, the steel barrel can automatically enter the vacuum through the workpiece conveyor. Vigorously develop small, ultra-high precision, ultra-high speed and intelligent control processing equipment box, and then manually press the start button, the vacuum box door can automatically close, vacuum pumping, leak detection, etc. will be carried out automatically. If it is qualified, the system will prompt, and if it is unqualified, it will automatically alarm. The degree of automation is very high, and the beat is very fast, up to 2 ~ 3 workpiece/min

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