Piston vacuum pump in electron beam melting furnace of application
General electron beam melting furnace consists of electron gun chamber and melting chamber. The vacuum chamber can be vented by piston vacuum pump and diffusion pump to obtain the vacuum degree of 10-4~10-6 torr. The melting chamber can be composed of piston vacuum pump, booster pump and diffusion pump or adopt multi-stage roots pump exhaust to obtain the vacuum degree of 10-2~10-6 torr.
Electron beam melting furnace: electron beam melting furnace mainly USES the huge heat energy emitted by electron beam as the heat source of melting or alloy smelting. It plays the same role as vacuum induction furnace and vacuum electric arc furnace. Because of the high cost of smelting, it is only used for melting refractory metals, active metals or alloys.
Piston vacuum pump has its special performance, which is summarized as follows:
1, piston vacuum pump is dependent on the piston in the water cylinder to change the volume of the pump chamber and absorb and discharge the liquid, this effect is called “positive displacement”. Therefore, it has a dry absorption capacity, that is, before the start of the pump room without filling water can absorb water. This is the great advantage of all “positive displacement” pumps.
2. The discharge valve and suction valve on the piston vacuum pump are very important, but these valves on the one hand increase the hydraulic loss of the pump, on the other hand, it is very sensitive to the inclusion of liquid magazine. Therefore, the piston vacuum pump can not be used to discharge dirty liquid and high viscosity liquid, so as to avoid in the process of operation, valve failure, resulting in management difficulties.