Composite molecular pump is a series combination of molecular pump and traction molecular pump, set the advantages of the two pumps in one. Pump in a wide range of pressure ((10-6 ~ 1Pa) has a larger pumping speed and higher compression ratio, greatly improving the pump outlet pressure.Australian company Alcatle produced a static pressure bearing and Dynamic seal of the composite molecular pump, can be completely oil-free, and without the first stage pump directly to the atmosphere exhaust.Complex molecular pump in many forms, according to the structure points, there are two main: one is the turbine blades and disk Type traction pump in series combination; the other is the turbine blade and the cylinder traction pump series combination of the turbine stage is mainly used to improve pump pumping speed, generally used to help increase the pumping speed of the blade shape, the level of l0 Traction grade is mainly used to increase the compression ratio of the pump to increase the outlet pressure of the pump.Disc Traction level is to open several profile grooves according to a certain rule in the plane of the flat disk and then connect the several disks in series Composition, there are Archimedes spiral type line, logarithmic spiral, arc line, etc. When pumping gas by high-speed rotation of the disc to "drag" to make it along the trench from the inside and outside and Reciprocating from the outside to the inside of the directional flow, And to achieve the purpose of pumping. Cartridge traction level in the cylindrical rotor or stator cylindrical surface to open a certain cross-sectional shape of the groove, such as rectangular, circular arc, triangular and other shapes of spiral groove. Traction pump line groove open in the outer surface of the rotor cylinder or the pump body surface, so you can take full advantage of the cylindrical outer cylinder line speed higher gas molecules momentum transfer, improve pump pumping effect.In the design and manufacture, By changing the angle between helical groove channel and suction direction (helix angle), the ideal suction effect is achieved.In the design of compound molecular pump, the response between turbine stage and traction stage must be handled And the convergence relationship.As the turbine stage has a larger pumping area, pumping speed is large, while the traction groove groove pumping area smaller, at the junction of the two structures, by the turbine blades compressed gas molecules flow A sudden change, so that the movement of gas molecules in the joints from the disorder into disorder, to make reflux increased, decreased suction capacity.Therefore, the design should be added at the turbine level and traction conversion With the continuous improvement of the composite molecular pump, its application fields are more and more widely. In some pumping systems, the diffusion pump can be replaced to shorten the pumping time of the system, and A clean, vacuum-free environment is available.