Molecular pump is a kind of vacuum pump which uses the high-speed rotating rotor to transfer momentum to the gas molecules to obtain the directional speed, so that it is compressed, driven to the exhaust port and then pumped out for the front stage. Because the groove of the simple traction pump is opened on the outer surface of the rotor cylinder or the inner surface of the pump, the momentum transfer of the gas molecules can be made full use of the higher linear speed of the outer circle of the cylinder to improve the pumping effect of the pump.
Because the turbine stage has a large extraction area and a large extraction speed, while the traction stage has a small groove extraction area, at the joint of the two structures, the flow pattern of the gas molecules compressed by the turbine blades suddenly changes, which makes the movement of the gas molecules in the joint from orderly to disordered, to increase the return flow and reduce the extraction capacity.
Molecular pump applications:
Analysis (mass spectrometry, electron microscopy, etc.)
Semiconductors (electronic components, integrated circuits, flexible solar cells, etc.)
Optics / glass (thermal protection, antireflection, reflection, optical filter film)
Coating (surface protection, decorative coating, display, screen)
Vacuum metallurgy (vacuum furnace, vacuum brazing, vacuum sintering, vacuum alloy,)
Leak detection (vacuum system, vehicle tank, air bag
Research experiments (medical MRI, nuclear particle physics, nuclear fusion research, laser applications and many more)
Lamp production industry and related
Working conditions of molecular pump:
Since the rotor speed reaches 20000r / min, the starting time of the molecular pump is longer.
The gas is in the molecular flow state, so it needs to be equipped with a pre-stage pump. Generally, a rotary vane pump is used as the pre-stage pump.
Molecular pump features:
Oil lubricated molecular pump: the amount of lubricating oil is small, and in the front vacuum section, the pollution to the vacuum chamber is small.
Grease lubricating molecular pump: the amount of grease is very small, and the pre graded dry pump can obtain a clean vacuum without oil.
All magnetic suspension molecular pump: it does not need lubrication and can be used together with dry pump to obtain clean vacuum environment without oil.