Search results
Results from the WOW.Com Content Network
Interior view of a turbomolecular pump. A turbomolecular pump is a type of vacuum pump, superficially similar to a turbopump, used to obtain and maintain high vacuum. [1] [2] These pumps work on the principle that gas molecules can be given momentum in a desired direction by repeated collision with a moving solid surface.
The solvent is pumped as a liquid as it is then almost incompressible; if it were pumped as a supercritical fluid, much of the pump stroke would be "used up" in compressing the fluid, rather than pumping it. For small scale extractions (up to a few grams / minute), reciprocating CO 2 pumps or syringe pumps are often used.
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.
Vacuum systems usually consist of gauges, vapor jet and pumps, vapor traps and valves along with other extensional piping. A vessel that is operating under vacuum system may be any of these types such as processing tank, steam simulator, particle accelerator, or any other type of space that has an enclosed chamber to maintain the system in less than atmospheric gas pressure.
Advantages of air abrasion include that it preserves more healthy tooth tissue (which can increase the strength and longevity of restorations), and has less risk of fracturing or chipping a tooth when compared to a traditional pneumatic dental drill. Air abrasion generates minimal noise, vibration, pressure, and heat, all of which can increase ...
Vacuum pumps: A vacuum pump sucks air or air/steam mixtures from the chamber. Superatmospheric cycles: Achieved with a vacuum pump. It starts with a vacuum followed by a steam pulse followed by a vacuum followed by a steam pulse. The number of pulses depends on the particular autoclave and cycle chosen. Subatmospheric cycles:
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.
VSA differs from other PSA techniques because it operates at near-ambient temperatures and pressures. VSA typically draws the gas through the separation process with a vacuum. For oxygen and nitrogen VSA systems, the vacuum is typically generated by a blower. Hybrid vacuum pressure swing adsorption (VPSA) systems also exist.