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A molecular drag pump is a type of vacuum pump that utilizes the drag of air molecules against a rotating surface. [1] The most common sub-type is the Holweck pump, which contains a rotating cylinder with spiral grooves which direct the gas from the high vacuum side of the pump to the low vacuum side of the pump. [2]
A vacuum ejector, or simply ejector, or aspirator, is a type of vacuum pump, which produces vacuum by means of the Venturi effect.. In an ejector, a working fluid (liquid or gaseous) flows through a jet nozzle into a tube that first narrows and then expands in cross-sectional area.
The sorption pump is a vacuum pump that creates a vacuum by adsorbing molecules on a very porous material like molecular sieve which is cooled by a cryogen, typically liquid nitrogen. The ultimate pressure is about 10 −2 mbar. With special techniques this can be lowered till 10 −7 mbar.
A partial vacuum may be generated by increasing the volume of a container. To continue evacuating a chamber indefinitely without requiring infinite growth, a compartment of the vacuum can be repeatedly closed off, exhausted, and expanded again. This is the principle behind a positive displacement pump, for example the manual water pump. Inside ...
Vacuum technology is based on differential air pressure. Rotary vane vacuum pumps generate an operation pressure of -0.4 to -0.6 bar at the vacuum station, which is also the only element of the vacuum sewerage system that must be supplied with electricity. Interface valves are installed inside the children collection chambers. They work ...
An oil diffusion pump is used to achieve higher vacuum (lower pressure) than is possible by use of positive displacement pumps alone. Although its use has been mainly associated within the high-vacuum range, down to 1 × 10 −9 mbar (1 × 10 −7 Pa), diffusion pumps today can produce pressures approaching 1 × 10 −10 mbar (1 × 10 −8 Pa) when properly used with modern fluids and accessories.
A gas lift or bubble pump is a type of pump that can raise fluid between elevations by introducing gas bubbles into a vertical outlet tube; as the bubbles rise within the tube they cause a drop in the hydrostatic pressure behind them, causing the fluid to be pulled up.
The NEG acts as a getter or getter pump that is able to reduce the pressure to less than 10 −12 mbar. Non-evaporable getters , which work at high temperature, generally consist of a film of a special alloy, often primarily zirconium ; the requirement is that the alloy materials must form a passivation layer at room temperature which ...