The leakage inspection of high-purity sulfur hexafluoride can be divided into qualitative inspection and quantitative inspection. The qualitative inspection is to directly inspect the aluminum castings at each joint sealing point of the equipment, so as to find out the location of each leakage point of the equipment. Quantitative inspection is to calculate the leakage amount through wrapping detection, bottle hanging method or pressure conversion, so as to obtain the annual leakage rate.

Qualitative high purity sulfur hexafluoride leak detection includes vacuum leak detection and leak detector detection:

① The vacuum leak detection method is to vacuum the equipment to 40Pa, stop the pump for 0.5h, read the number A on the vacuum gauge, and then stop for 5h to read the number B. If B - A ≤ 133Pa, it is considered that the sealing is good;

② Leakage detection by leak detector is to move the probe of the leak detector along the surface of each connection port of the equipment and the surface of the aluminum casting, and judge the gas leakage according to the readings of the high-purity sulfur hexafluoride leak detector.

Attention shall be paid to: the probe shall move slowly to prevent the probe from moving too fast and missing the leak point; During the leak detection, the high purity sulfur hexafluoride leakage gas shall not be blown away by the wind and affect the leak detection when the wind speed is high; The leak detector with high sensitivity and low response speed shall be selected, and the * * * low detection amount of the leak detector is generally used

Quantitative leak detection usually adopts methods such as buckle cover method, bottle hanging method, local binding method and pressure drop method. The cover fastening method is applicable to high-voltage circuit breakers and small equipment, the bottle hanging method is applicable to those with double sealing grooves on the flange surface, the local binding method is generally used for assembling units and large products, and the pressure drop method is applicable to measuring the air leakage rate when the air leakage in the equipment compartment is large or during operation. Generally, in the handover acceptance test of Liming sulfur hexafluoride equipment, leakage detection is carried out by using local binding method and buckle cover method.

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