Differential Pressure Air Tightness Tester: Principle and Operation

B. Differential pressure (also known as comparative) air tightness tester: There are two interfaces at the back of the instrument, one connected to the standard product (qualified product) and the other connected to the test product. 1) The instrument simultaneously pressurizes the standard product and the test product with equal air pressure. Then the air source is cut off, and the difference between the air pressure in the standard product and the air pressure in the test product is observed. If the difference is zero, it means that the test product is qualified just like the standard product; otherwise, the test product is considered unqualified. 2) If the product does not have an inflation hole, a volumetric differential pressure air tightness tester is used. Two sealing chambers of the same size as the shape and specifications of the product need to be created. Then the instrument pressurizes the space between the standard product, the test product, and the mold separately. After cutting off the air source, the difference between the air pressure in the standard product and the air pressure in the test product is observed. If the difference is zero, it means that the test product is qualified just like the standard product; otherwise, the test product is considered unqualified.