Pumping Systems

Three types of pump systems: positive displacement, momentum transfer, and entrapment.

Positive Displacement Pumps

Positive displacement: Uses a mechanism to repeatedly expand a cavity, allow gases to flow in from the chamber, seal off the cavity, and exhaust it to the atmosphere.

Momentum transfer: Uses high speed jets of dense fluid or high speed rotating blades to knock gas molecules out of the chamber. Ex: Diffusion and turbo molecular

File:Cut through turbomolecular pump.jpg

capture gases in a solid or adsorbed state. Ex: Ion and sorption pumps