From refrigeration and air conditioning technology to automobile manufacturing, from semiconductor manufacturing to solar energy technology, the more precise high-tech products require high airtightness, and leak detection technology has become an indispensable part of product manufacturing and use. High quality leak detectors can not only effectively improve product quality and production safety, but also effectively reduce the time and capital required for product maintenance and troubleshooting. But how to conduct product leak detection more efficiently? What should be noted during the leak detection process? 001.png

1、 Before filling the leak detection gas, the specimen must be evacuated

It is completely necessary to pre evacuate the specimen before filling it with leak detection gas for proper leak testing, especially for specimens with long and narrow geometric shapes. If the air in the specimen is not evacuated before filling, it will be compressed to the end of the geometric space, and the leak detection gas cannot enter this area, so potential leaks will only release air, and the leak detector cannot detect these leaks.

If low-pressure leak detection gas is used to fill the specimen, evacuation is also particularly important because residual air in the specimen will dilute the filled leak detection gas. For example, if there is residual atmospheric pressure air in the specimen, after adding one atmosphere of leak detection gas, the concentration of leak detection gas in the specimen will decrease to 50%. However, if two atmospheres of leak detection gas are added, the concentration of leak detection gas will be 66%.

2、 Do not use a sink to test for leaks before gas leak testing

The leakage holes in leak gas testing are usually very small or narrow capillary tubes. If the leakage holes are placed in a water tank before leak gas testing, they will be blocked or filled with water. Due to surface tension, the water trapped in the leakage holes will be very difficult to expel from the small holes, greatly affecting the leak detection results. The only solution to this problem is to eliminate these moisture through a lengthy drying process.

3、 Do not empty or overflow leak detection gas into the leak testing area

The minimum detectable leak rate in leak testing is closely related to the background concentration of the leak detection gas. Although leak detectors only detect changes in the concentration of the leak detection gas, high background concentrations tend to exhibit high absolute fluctuations. If the leak detection gas is discharged into the leak detection area after the leak test, the background concentration will continue to increase throughout the entire working day. In addition, it is necessary to ensure that there is no gas overflow during filling or discharging, and to regularly check for leaks in the connectors.

4、 Check for major leaks before filling leak detection gas

Before filling the leak detection gas, it is necessary to quickly test for the presence of major leaks. Otherwise, the leak detection gas overflowing from the large leak hole will contaminate the leak detection area. The simple testing method for large leaks is to evacuate the specimen and observe whether the evacuation pressure is maintained in a short period of time. If the specimen can maintain the evacuation pressure, it indicates that there are no large leaks and can be filled with leak detection gas.

5、 Provide sufficient ventilation conditions for the leak testing area

If the leak detection gas helium/hydrogen leaks, it will fly like a balloon to the top of the leak detection area and gradually float throughout the entire leak detection area. Although all connecting components are completely sealed, a small amount of leak detection gas may inevitably be released during the connection or disassembly process. Therefore, it is very important to provide sufficient ventilation conditions for the leak testing area. Due to the upward movement of both leak detection gases, it is recommended to introduce fresh air from the bottom and discharge gas from the top to the outside.

6、 Ensure that the direction of leakage testing is the same as the direction of pressure experienced during use

Many seals have a preferred installation direction and can only provide a sealing effect in this direction. For example, radial shaft seals only have a sealing effect in one direction, and leakage will occur in the opposite direction. Similarly, there are many seals that have similar situations. If the direction of the leak test is the same as the direction of the pressure applied during use, it will be easy to find the actual leak without being disturbed by false alarms.

7、 The leakage test pressure is the same as the pressure experienced during operation

Many seals leak at a certain pressure threshold. If leakage is not tested under the * * pressure during operation, some leaks should not be detected. Therefore, using a higher testing pressure during the leak detection process can effectively detect leaks that did not occur during actual operation.

8、 Avoid the influence of cross ventilation on the suction gun in the leak testing area

Usually in production environments, air flow occurs between different areas due to temperature differences, fans, or other air flow factors. Any air flow has a certain negative effect on leak detection ability, because the gas being detected will be blown away from the opening of the suction gun probe by the through air. In order to achieve good test results, the leak testing area should be shielded from the adverse effects of these winds.