Development Of Polyethylene Gas Vale Automatic Welding Equipment

Currently, the welding devices, which are used for the welding of polyethylene gas valves, have many problems such as low degree of automation, poor welded quality, inconvenient to use and so on. To solve these problems, one basic knowledge of plastic welding and one mechanism of influenced element related to welded quality were introduced briefly, and then some theories of plastic welding were probed with the microscopic point of view, and then some welding parameters of polyethylene gas were determined by making some tests. According to the relevant requirements, a relative high degree of welding device was developed. At last, the quality of end welding product was assessed with a set of rigorous testing process.Firstly, the basic knowledge of plastic welding is introduced briefly to get a preliminary acquaintance of mechanism of plastic welding. On the basic of it mentioned above, three plastic welding theories were introduced to explore the nature of plastic welding. Especially, the effect of thermal motion of molecule on the welding process was studied. In order to obtain the welding parameter of gas valves, a proven flow chat of plastic welding and the influence of welding quality are introduced in this paper. The heating process of polyethylene pipe is analyzed to obtain the relationship between melt layer and time. Then, a series of orthogonal tests are performed to obtain the welding parameter of polyethylene gas valve device, which are also used for welding parameters when checking the device latter for acceptance.Secondly, in connection with the drawbacks of the current welding of polyethylene gas valves, a scheme, which is designed to solve these drawbacks mentioned above, is presented. Based on the experiment requirement and the scheme, the mechanical part of the welding set is designed. In addition, some analyses of some parts from the device such as strength analysis, thermal analysis, are performed. Then, the device’s control system, which based on the set’s movement and the proposals raised by workers, is developed, and it was integrated organically into the entire at the last.Finally, some quality tests of welding product are performed, especially the hydrostatic strength test which is the most important one. The finding of all tests shows that the quality of welding polyethylene gas valves is conforming to the National Standards, which in turn means the welding device have been devised successfully.