Differential Pressure Leak Tester: Principle and Application

B. Differential Pressure (also known as Comparative) Leak Tester: The instrument has two interfaces at the back, one connected to the standard product (qualified product) and the other connected to the test product.

1. The instrument simultaneously pressurizes the standard and test products with equal pressure. Then the air source is shut off, and the difference between the pressure in the standard product and the pressure in the test product is observed. If the difference is zero, it indicates that the test product is qualified, just like the standard product. Otherwise, the test product is deemed unqualified.

2. If the product does not have an inflation hole, a volumetric differential pressure leak tester is used. Two sealing chambers of the same size as the product's shape and specifications need to be created. Then the instrument pressurizes the space between the standard product and the test product with the mold separately. After that, the air source is shut off, and the difference between the pressure in the standard product and the pressure in the test product is observed. If the difference is zero, it indicates that the test product is qualified, just like the standard product. Otherwise, the test product is deemed unqualified.