Vapor pump

Pumps where the pumping effect is based mainly on the diffusion of gases into a gas-free high speed vapor jet (vapor pumps)... 

Water vapor pumps Oil vapor jet pumps Mercury vapor jet pumps... 

Fig. 2.48 Pumping speed of various vapor pumps as a function of intake pressure retated to a nominat pumping speed of 1000 i/s.

Included in the class of fluid-entrainment pumps are not only pumps that use a fast-streaming vapor as the pump fluid, but also liquid jet pumps. The simplest and cheapest vacuum pumps are water jet pumps. As in a vapor pump (see Fig. 2.46 or 2.51), the liquid stream is first released from a nozzle and then, because of turbulence, mixes with the pumped gas in the mixing chamber. Finally, the movement of the water - gas mixture is slowed down in a Venturi tube. The ultimate total pressure in a container that is pumped by a water jet pump is determined by the vapor pressure of the water and, for example, at a water temperature of 15 °C amounts te about 17 mbar. 

Backstreaming vapor pump fluids, vapors of oils, rotary pump lubricants, and their cracking products can significantly disturb various working processes In vacuum. Therefore, It Is recommended that certain applications use pumps and devices that reliably exclude the presence of hydrocarbon vapors. 

With strongly degassing rolls of paper, it may be necessary to install a cold surface in the winding chamber to act as a water vapor pump. The rolls of the plastic web or paper typically have diameters between 400 and 1000 mm and a width of 400 to 3000 mm. A precise, electronically controlled... 

Two widely used vacuum pumps are the mechanical rotary oil-seeded pump and the vapor pump. The former provides a medium vacuum and works relative to the atmosphere. The vapor pump, on the other hand, provides a high or very high vacuum and operates relative to a medium vacuum provided by a rotary pump, referred to as a backing pump in this connection. Thus, the most widely used high-vacuum system able to establish an ultimate pressure of about 10-< torr or below consists of a vapor pump backed by a rotary pump. 

Resonant 3-photon ionization with pulsed laser (Cu-vapor pump laser) ion detection after photo-ionization rare earth in preparation (P78)... 

Cryogenic and turbo pumps are known for their cleanliness and effectiveness. However, these pumping systems are very expensive and require significant training for proper operation. The most common auxiliary pump used in the laboratory is the diffusion (or vapor) pump. 

A diffusion pump (also called a vapor pump) has no moving parts, yet is considered a fast pump. By itself, the diffusion pump cannot move gases from one place to another. However, under specific conditions, it can compress gases to a specific region within itself. Used in tandem with an auxiliary pump (such as a mechanical pump), these compressed gases can be expelled out of the system. 

The tube is a large X-ray tube with an electron-emitting filament heated by an insulated transformer. A potential of 150,000 to 300,000 volts D. C. is applied and the electrons are drawn over to the positively charged electrode which is in the form of a nickel window. The window, only 0.0012 cm. in thickness, is supported on a grid attached to a thin copper tube which is sealed into the glass tube. A high vacuum must be maintained by continuous evacuation with a mercury vapor pump. The electrons issue in a beam which is soon scattered by the air molecules but the electrons will penetrate up to forty or fifty centimeters in air or other gas. 

Cavitation] [fluid vaporizes] /pump rpm too fast/suction resistance too high/ clogged suction line/suction pressure too low/liquid flowrate higher than de-sign/entrained gas. 

The reboilers are suppressed-vaporization pump-through types with pumps (286) and (288), respectively, which also pump out the bottom products from the associated fractionation column. Finished product from second fractionation column (274) is pumped via pump (290) to product tankage, not shown. ... 

Figure 4.1 Fluorescence spectrum (fluorescence intensity as a function of fluorescence wavelength) for Naa vapor pumped by a 5682-A4 krypton ion laser. This wavelength excites Na2 molecules from v" = 3, J" = 51 in the electronic ground state to v = 34, J = 50 in the excited electronic state. The shown fluorescence lines result from transitions from the laser-excited level down to v" = 4 through 56 in the electronic ground state. Reproduced by permission from K. K. Verma, A. R. Rajaei-Rizi, W. C. Stwalley, and W. T. Zemke, J. Chem. Phys. 78. 3601 (1983).

W.T. Silfvast, J.J. Macklin, O.R. Wood II High-gain inner-shell photoionization laser in Cd vapor pumped by soft X-ray radiation from a laser produced plasma source. Opt. Lett. 8, 551 (1983)... 

Cryopanel (vacuum technology) A vapor pump that operates by cryocondensation of vapors on a large-geometrical-area cold surface at a temperature < - 150°C where the vapor pressure of water is very low. Also called a Meissner trap. See also Cryopump. 

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