General requirements for vacuum leak detection

    There are many methods of leak detection, but each has its own characteristics and scope of application. Which method is more appropriate depends on the specific situation. For example, the required sensitivity of leak detection, system structure, materials, pressure resistance, existing conditions (personnel, equipment, leak gas), cost, etc. In short, it is necessary to meet the requirements while being as simple and convenient as possible. As an ideal leak detection method, it should meet the following requirements.

1) The method is sensitive: very small leaks can be detected.

2) Short reaction time: The time needed to find a leak should be short in order to speed up the leak detection speed. A device needs a lot of parts for leak detection, the workload is very large, and the short response time not only saves time, but also can accurately locate the leak.

3) Able to locate and quantify: that is, not only to be able to find the location of the leak, but also to determine the size of the leak rate in order to determine whether it meets the quality requirements. For repairing welds or replacing sealing rings, it can be targeted, which is also very important for analyzing technological reasons.

4) Non-destructive leak detection: it does not need to destroy the original structure of the device during leak detection, and it does not cause the device to be contaminated. For example, the back pressure leak detection method has been widely used in the inspection of the sealing performance of electronic components, electrical vacuum device sealing hollow spheres, etc.

5) Good stability: Sensitivity is required to be stable and reliable for a long enough time in order to carry out cumulative test and quantitative measurement, and to ensure the reliability of the test.

6) The content of all leaking substances in the air should be low, not corrosive to parts, and as non-toxic or less toxic as possible, so as not to block leaks, etc.

7) Wide range of leak detection: from large leaks to small leaks can be detected to reduce the quantity and cost of equipment.

8) Leak detection equipment should be simple in structure, convenient in operation and maintenance, and economical and applicable.

9) Oil-free leak detection: Some special devices and oil-free systems, especially oil-free systems in operation, require leak detection to be oil-free. After adopting an oil-free or semi-oil-free system with a limited pumping speed for nitrogen, or taking appropriate oil-retaining measures, the purpose of oil-free or oil-less leak detection can also be achieved.

    However, the above requirements are often contradictory, and it is impossible to require a method to meet the above requirements at the same time. For example, the structure of general sensitive leak detectors is more complicated, and it is more difficult to use and maintain, and the price is more expensive. Therefore, only suitable methods can be selected for different leak detection objects, and the principle of solving the main contradictions is the principle.

(huiputech)