It is the use of variable pump speed rotation of the rotor to transfer momentum to the gas molecules, and thus obtain the orientation speed, so as to be compressed, is driven towards the exhaust port of the preceding stage is drawn away after a vacuum pump. Such a pump can be specifically divided into: 1) molecular pump rotor traction gas molecules collide with the high-speed movement of momentum is obtained, to be driven to the outlet of the pump. 2) turbo molecular pump by high-speed rotation of the rotor blades and the stationary blade with each other to achieve a given pumping. Such pumps are typically operate at the molecular flow state. 3) It is a series of composite molecular pump and towed by two turbo molecular pumps combine a complex molecular pump pressure limiting type variable vane pump can be adjusted automatically according to load size refinement variable flow pumps and reasonable power utilization variable pump can reduce heating oil, so often used to perform elements require fast or slow or packing requirements of the occasion. Fast load is small, low pressure, flow, pump in characteristic curve segment. Slow feed, load, high pressure, variable flow pumps and small maintenance, the pump automatically switches to characteristic curve segment. When packing, at near point work, provide a small leakage flow to compensate for this limited-pressure system variable vane pump rated pressure 6.3pa? Specializing variable pump *, Jing Chong hydraulic (certified), variable pump hit by Jinan crystal Hydraulic Machinery Limited. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) Shandong Jinan, mining machinery leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum meet customer needs. In the crystal to create a hydraulic leadership with the staff warmly welcome all inquiries negotiations to create the crystal to create a better future for the hydraulic.