Present situation of air tightness detection technology and its development direction automation technology
气密性检测It is an important process to ensure product quality and production safety. Its role in the production process has been widely recognized, and its application field is also more and more wide. From the previous automobile manufacturing industry, it has been expanded to the current general electronic components, household appliances, security products, medical devices, etc.
Air tightness detectorThe main function is to determine the product sealing, waterproof performance, and leakage.
The common methods of air tightness testing are bubble method, smear method,Air tightness test methodPressure drop method, flow method, ultrasonic method and so on. Traditional leak detection methods mostly use bubble method and smear method. Bubble method is to immerse the workpiece in water, fill it with compressed air, and then collect the leaked bubbles in a certain period of time to measure the leakage. Daub method is to daub soapy water on the surface of the workpiece which is filled with a certain air pressure, and observe the bubbles to detect the leakage. These two methods are easy to operate, and can directly observe the leakage position and leakage situation. However, it is difficult to collect all bubbles because of not knowing the leakage position and several leaks in advance, which affects the accuracy of measurement; Secondly, for large, bulky and complex parts, bubbles are attached to the bottom and folds of the parts and are not easy to observe; After the test, the workpiece needs to be cleaned and dried, which can not achieve automatic and quantitative leakage detection. Therefore, these two methods can not meet the needs of high-precision and high-efficiency production.
Current situation of air tightness testing technology at home and abroad
In order to improve the detection accuracy and efficiency, and realize the detection automation, the current popular method of air tightness detection is differential pressure method. If there is leakage in the tested container, it will inevitably lead to the loss of gas quality and the decrease of pressure in the container, which will reduce the original pressure in the container. By measuring the gas pressure drop in the container, the actual amount of gas leakage in the container can be deduced, In order to achieve the purpose of air tightness test.
气密性测试仪The relationship between leakage flow and differential pressure can be expressed as follows:
PT is the test pressure, P0 is the external pressure (atmospheric pressure), VW is the volume of the tested vessel, vs is the volume of the reference vessel, V is the change of the content product of the differential pressure sensor caused by the differential pressure; Delta; VL is the amount of leakage discharged into the atmosphere; Delta; P is the differential pressure, QL is the gas leakage flow, t is the test time corresponding to the differential pressure △ P. PT P0 is absolute pressure.
Based on the above basic principles, many manufacturers at home and abroad have developed theAir tightness detectorThe famous company in China is Harris Automation Technology Co., Ltd. Harris is a pioneer in manufacturing air tightness testing instruments in the world, involving automobile, household appliances, die casting, packaging, valves, electronics, aviation and other fields. Hiris also produces many types of air tightness tester, providing a variety of detection modes. At the same time, considering the leak detection performance, leakage, and the volume and leakage of different objects in practical application, hiris provides corresponding products.
Due to the increasing demand for waterproofing and the development of mechanical automation, the air tightness tester must develop in the direction of automation if it wants to get better development.
The automatic air tightness tester provides the guarantee of speed, releases the human resources, and provides the guarantee of speed and cost for the waterproof and air tightness detection of enterprises.
Now the air tightness detector of Harris has realized the automatic technology, which can be used for the automatic detection of the production line, and has won the recognition of the majority of customers. It has become the wind vane of air tightness detector
The parameters of Harris air tightness tester are as follows:
Air supply pressure: 0.4 ~ 1.2MPa
Power supply voltage: 220 V / 50 Hz or 110 V / 60 Hz
Pressure regulation range: - 40 ~ - 0.5kpa, 5 ~ 150kPa
Pressure regulation accuracy: 0.1kpa
Pressure test range: - 80 ~ 150kPa
The minimum resolution of pressure attenuation test is 1pA
Minimum resolution of leakage flow test: 0.01ml/min