Introduction to pressure test of seals

The principle of the sealing method is to fill the air to be tested with compressed air. After the air pressure reaches the working pressure, the air source is cut off and the rated time is kept. If the seal has a woman's point, the air pressure in the chamber will gradually decrease. During the rated check-side time, the pressure sensor continuously converts the pressure value into an analog quantity and sends it to the secondary meter to compare with the rated value for position control. .


The disadvantage of pressure method for detecting side seal reliability is low detection accuracy and long detection time. When the working pressure of the detection gas is set to 0.2 MPa, considering the relationship between the optimal working area of the meter and its fullness value, it is obvious that a pressure sensor with a full scale value of 0.25 MN and a secondary instrument should be selected.
 
If the accuracy of the sensor and the secondary meter is 0.5, the detection error is only when the amount of the leak is accumulated to a large extent. When the pressure loss is on the order of magnitude, it can be accurately pointed out. This means that a longer rated test time needs to be set. But for large-scale online piece-by-piece inspection is difficult to accept. In fact. When the rated detection time is short, the small leakage of the emblem will not be able to be sideways. If the production process does not allow for an effective extension of the inspection time, a false positive may occur. At present, manufacturers also use this test method. but. The pressure method will gradually be eliminated from the production process.