The Design And Research Of Automatic Test Line For The Safety Of Liquefied Gas Valve

Liquefied gas valve as the most important accessory of cylinder, mainly serves as a connection between cylinders and cylinder sealing. Once its safety can not be guaranteed, it will cause gas leak, met the fire will generate an explosion, a direct threat to personal and property safety of users. So it has great practical significance for 100% detection of cylinder valve safety performance.This paper analyzes the impact of the cylinder valve safety performance factors, in contrast to the advantages and disadvantages of traditional detection method, we determined the method of leak detection based on gas sensors and the thread processing quality detection methods based on image processing technology. The gas of testing used 4% hydrogen and 96% nitrogen, we use the difference of density which detected by a sensor to calculate the amount of leakage of gas, and then determine the sealing performance of the workpiece; in the cylinder valve air inlet thread processing quality detection, using an image acquisition system to standard image of the external thread, the thread profile outer edges of the image obtained by image processing, and to develop a standard image template, while its parameters are stored in a standard database when detected, the test will be a good deal with externally threaded cylinder valves image input into the software, according to the relevant standard of the image and the template image thread test product is within the standard range, it is determined whether the detected thread for qualified products. According to "Gas Cylinder Safety Supervision provides that" 100% of the cylinder valve safety testing requirements, we design a liquefied gas cylinder valve safety performance automated test line. the structural design of the entire detection line based on modular design features of different combinations of products to meet the market needs of different design requirements. Control system uses the up or down bit machine combines control, the operating procedures of written by Lab VIEW, inspection station for 11 working process real-time monitoring and fault display, the next crew preclude the use of Siemens PLC S7-300 to control each motor and cylinder action, while using the proximity sensor to detect the moving part position signal, as a feedback signal of PLC, the servo motor is running to ensure the accuracy of the device.Experimental results show that the prototype template matching method is a very effective method for detecting an external thread, a single detection time within the range of 270~320ms, with a high detection efficiency; seal inspection station of the detection time from l min/piece down to the 20s/piece, detection efficiency increased by nearly three times faster than the existing method for detecting leakage has also been quantified measure; after each station can achieve detection invest 100% inspection of the product before put into use. While the modular design of the detection line detection beats less than 30 S, it meet the testing requirements of industrial automation, and greatly promoted the development of the valve industry.