Both air tightness detectors and seal testers are instruments for checking product leakage. Air tightness detectors are mainly used to test workpieces such as pressure vessels, valves and pipe fittings, while seal testers are designed to inspect the sealing performance of packaging bags, boxes, bottles, cans and other containers. In addition, air tightness testing adopts gas as the testing medium, whereas seal testing can use either gas or liquid.

Based on different testing principles, air tightness and seal testing equipment can be divided into two types: 1. Positive pressure air tightness test, which works by charging the workpiece with compressed air; 2. Negative pressure air tightness test, which adopts vacuum evacuation principle.