Air tightness detection is of great importance to industrial products. Due to its light weight, low cost and high efficiency, plastic is widely used in industrial products, especially for complex box products, which has obvious economic benefits. In this paper, we introduce a plastic enclosure for products based on the differential method of detecting technology of air tightness test, using propane tanks to provide stable pressure gas measured gas box body, at the same time with high precision pressure sensor to real-time detection of casing pressure, pressure after a period of time to detect casing pressure attenuation, the product under test pressure attenuation value attenuation value compare to the sample, to determine whether the box sealing meet the requirements. The whole testing device selects AT89S52 single chip computer control module, high-precision pressure sensor, LCD LCD display, alarm and reminder device, etc. The device is debugged and simulated by PID control and PROTUES software simulation, and verified. The experimental results show that the air tightness detection device, which can be judged by its own results by using differential pressure method as the detection principle and selecting intelligent control components, meets the requirements of production, and is also a further exploration and innovation of the air tightness testing method of plastic box products, which has practical production significance.
Keywords: Air Tightness、Differential pressure method、The pressure attenuation、Mechanical design、PID control
