Differential Pressure Air Tightness Tester: Principle and Applications

B. Differential pressure (also known as comparative) air tightness tester: The instrument has two interfaces at the back, one for connecting standard products (qualified products) and the other for connecting the test product.

1. The instrument simultaneously injects equal air pressure into the standard product and the test product. Then, the air source is cut off, and the difference between the air pressure in the standard product and the test product is observed. If the difference is zero, it means the test product is qualified; otherwise, the test product is unqualified.

2. If the product doesn't have an inflation hole, a volume differential pressure air tightness tester is used. Two sealing chambers of the same size as the product's shape and specifications need to be created. The instrument then injects air pressure into the space between the standard product and the test product and the mold. The air source is then cut off, and the difference between the air pressure in the standard product and the test product is observed. If the difference is zero, it means the test product is qualified; otherwise, the test product is unqualified.