In the past, leakage inspection of general workpieces was mostly carried out using water immersion or soap water spraying methods, and the presence of leaks in the workpiece was determined based on the visual inspection of the tester. The size of the leakage depends on the subjective judgment of the tester, so it is difficult to eliminate the influence of human factors on the test results, and it also determines that it cannot quantitatively measure the leakage rate of the workpiece. In addition, after testing with this method, additional work such as cleaning, drying, and rust prevention treatment must be carried out on the workpiece, which brings unnecessary trouble to production.
The improvement of modern technology has greatly increased the standards for airtightness testing of products, giving rise to new leak detection methods. An airtight leak detector needs to be equipped with a high-precision pressure sensor to improve detection accuracy. Generally, an air pressure leak detector can detect small leaks in workpieces in a short period of time. According to the processes of different manufacturers, there are significant differences in product design. It can be set according to standards, national standards, or according to the needs of the process and domestic units. The airtight leak detector will automatically perform operations such as inflation, balance, detection, judgment, exhaust, display, alarm, and information transmission based on the set testing parameters and standards. Thus eliminating the influence of human factors in detection, achieving standardization, efficiency, and automation of leak detection work.
As a general leak detection method, leak detection machines sometimes use pressure gauges or pressure sensors to directly measure the pressure changes inside the tested workpiece, and then calculate the leakage amount of the workpiece. However, when the testing environment is complex, requires high accuracy, or has high testing pressure and small leakage, this method will have high requirements for pressure gauges or sensors, which makes the detection cost quite expensive, sometimes even impossible. The airtightness detector adopts high-precision electronic pressure sensors, which are provided with a stable detection gas source by the gas source according to the detection requirements. Then, the device pressurizes the measured workpiece. When the internal pressure of the workpiece reaches the detection pressure, the gas enters the detection stage after a period of stabilization.
When there is no leakage in the tested workpiece, the detection pressure remains basically unchanged. When there is a leakage in the tested workpiece, the gas pressure inside the workpiece gradually decreases as the gas leaks from the tested workpiece. The pressure sensor outputs the corresponding pressure change in real time, and then according to the pre-set parameters, the system automatically determines whether there is a leakage. The detection process is automated by the system, eliminating the influence of human factors.