Classification of vacuum pumps

According to the principles of operation can be classified into two main categories as follows:
- Gas-binding vacuum pumps
- Gas transfer vacuum pumps

1. Gas-binding vacuum pumps : The Adsorption pumps { include : Getter pumps , Cryo pump, condenser }
2. Gas transfer vacuum pump : There are two main types { gas-displacement and kinetic vacuum pumps }
In which :
+ Gas-displacement {

• Oscillation displacement pumps : diaphragm pump, piston pump, scroll pump 
• Double roto displacement pumps : roots pump, screw pump, claw type piston pump
• Single displacement pumps :liquid ring pump, rotary vane pump, multi-cell pump, rotary piston pump, external vane pump } 

+ Kinetic vacuum {

• Mechanical kinetic pumps : gas ring pump, turbopumps, axial pump, radial pump, molecular pump, turbomolecular pump
• Propellant pumps : propellant jet pump, liquid jet pump, steam jet pump, diffusion pump, diffusion ejector pump
•  Ion transfer pump }

Summary : 

Gas-binding vacuum pumps either bind the gas to a especially active substrate through gettering or condense the gas at a suitable temperature.

Gas-displacement pumps, which are also referred to as gas transfer pumps, are classified either as positive displacement pumps or kinetic vacuum pumps. 

Positive displacement pumps displace gas from sealed areas to the atmosphere or to a downstream pump stage. 

Kinetic pumps displace gas by accelerating it in the pumping direction, either via a mechanical drive system or through an aligned vapor stream that is condensed at the end of the pumping section.