CG-17 glass three high vacuum oil diffusion pump GG-17 glass, low expansion coefficient, better able to withstand high temperature differential change, so the pump than the same type of pump can withstand high temperature and longer service life. The pump is suitable for the electronics industry, such as tubes. kinescope. X-ray tube, and semiconductor monocrystalline silicon smelting purification, high-boiling oil distillation purification separation, fluorescent lamps, vacuum flask high vacuum exhaust equipment.