Helium mass spectrometry leak detection technology in the high-voltage electrical industry: ensuring product safety and reliability

In the high-voltage electrical appliance industry, among the necessary conditions for the production of GCB (Gas Circuit Breaker) and GIS (Gas Insulated Switchgear) with a voltage of 63kv and above, requirements for products to meet technical conditions and safety are put forward. High-voltage switchgear uses SF6 gas as the medium for insulation and arc extinguishing. Therefore, the product requires that the leakage amount of SF6 gas inside the switch should be small, that is, it should have good sealing performance.

In order to ensure the safety and reliability of products, it is necessary to detect leaks in components during the production process and for the finished products before leaving the factory. The traditional leak detection method using a halogen leak detector has low sensitivity, and is prone to leakage and false detection, resulting in the product's airtightness not meeting the requirements. Using a helium mass spectrometer leak detector can make up for these deficiencies, and at the same time, it can detect the leakage point and the leakage rate.

Helium Mass Spectrometry Leak Detection of Epoxy Insulating Parts in the Power Industry

The leak detection method of the helium mass spectrometer leak detector depends on the situation of the workpiece to be tested. For components with a small volume, such as bellows, various inflatable joints, and trachea weldments, the helium hood method is used. The workpiece to be tested is evacuated, and the leak detector is adjusted to a leak rate of (10^-11 Pa.m³/s). Then, helium is charged into the helium hood, and the leak rate display is observed at the same time. Once the leak rate increases, it indicates that the workpiece is unqualified.

The helium mass spectrometry leak detection method for high-voltage electrical appliances depends on the situation of the workpiece to be tested

Back Pressure Method

For workpieces with a large volume, the back pressure method is adopted, and leak detection tanks of different sizes are selected according to the size of the workpiece. Usually, the workpiece to be tested is charged with pure helium at 0.6MPa or a helium (30% content) - nitrogen mixed gas, and then placed in the leak detection tank.

Back Pressure Method

First, use the auxiliary evacuation system to pump the pressure below 5Pa, close the exhaust valve, open the leak detection valve, and conduct leak detection. If the leak rate exceeds the specified value, it is unqualified.

Suction Method

For sub-assembly or final assembly, the suction method is adopted. The workpiece to be tested is charged with a helium-nitrogen mixed gas, and a suction gun is used to find leaks at the assembly surface of the workpiece to be tested or at the suspected leak points. If the value displayed by the leak detector exceeds the specified value, it indicates that there is a leak.

Suction Method

Anhui Nuoyi Technology Co., Ltd. is a professional high-tech enterprise engaged in the research, development, production, and sales of helium mass spectrometer leak detectors, helium leak detection vacuum chambers, and recovery systems.

The company strictly implements international product standards and industry standards, applies modern business concepts and management methods, has strong technical support, and advanced production and testing equipment, and carefully manufactures high-precision instruments of the NOY brand with good stability, high efficiency, and complete functions.