Gas capture pumps

Gas Transfer Gas Capture Pumping Range" Relative Speed... 

The pumping speed of a cryosurface under free-molecular conditions can be predicted from kinetic theory if the proper capture coefficient is known. The capture coefficient, as defined by the ratio of the actual pumping speed to the theoretical maximum pumping speed [ ], is a measure of the fraction of molecules that stick or condense on the first collision with the cryosurface. The capture coefficient is related to the energy of the gas molecules being pumped as well as to the cryosurface temperature. If this relationship were known for a particular gas, the pumping speed at other temperatures could be readily predicted. 

The alpha-particle instrument is shown in Fig. 1. The gas, supplied from a conventional gas handling system, is irradiated in the ionization chamber. The radiation is supplied from an enclosed polonium alpha source of a few hundred millicuries. The irradiated gas bleeds through a leak out of the ion source and into the evacuated electrode chamber. There, the ions effusing from the leak are captured by the electric fields while the gas is pumped away. The ions are focused, accelerated, and then subjected to mass analysis and electron multiplier detection in a 90° sector field analyzer tube. 

As the rotor turns, the vanes remain in contact with the pump housing forming a moving seal. Pockets of gas, captured at the pump inlet, are swept through the chamber and is compressed as it nears the exhaust outlet thus creating a positive preasure that ejects the gas through the outlet, past a check valve. 

Capacity, pump (vacuum technology) The amount of a specific gas that a capture pump, such as a cryopump, can contain and still pump effectively. When this value is exceeded the pump is ineffective and must be regenerated. See also Regeneration. 

Pump capacity (vacuum technology) The amount of a specific gas that a capture pump,... 

With the primary pumps on, the high pressure in the inlet plenum compresses the gas captured in the OEMs and raises the sodium level in the OEMs to a region above the active core. When pumping power is lost in the primary system and the pressure drops, the gas expands, which results in a displacement of the sodium in the OEMs to a level below the active core. 

The collection of particles larger than 1—2 p.m in Hquid ejector venturis has been discussed (285). High pressure water induces the flow of gas, but power costs for Hquid pumping can be high because motive efficiency of jet ejectors is usually less than 10%. Improvements (286) to Hquid injectors allow capture of submicrometer particles by using a superheated hot (200°C) water jet at pressures of 6,900—27,600 kPa (1000—4000 psi) which flashes as it issues from the nozzle. For 99% coUection, hot water rate varies from 0.4 kg/1000 m for 1-p.m particles to 0.6 kg/1000 m for 0.3-p.m particles. 

Ethylene dibromide Lab method with pumped Tenax absorbent tubes, solvent desorption and electron capture gas chromatography 45... 

FIGURE 10< 108 The procedure to measure the capture efficiency by the tracer gas method, aj The measurement of the reference concentration in the duct, when the tracer is released direcdy into the duct, fb) The measurement of the concentration in the duct, when the tracer is released from the source, / -= sampling point, 2 = pump, J = analyter, 4 - injection of tracer, 5 = tracer gas flow meter, 6 = tracer gas cylinder. 

To pump out larger vessels, several adsorption pumps are used in parallel or in series. First, the pressure is reduced from atmospheric pressure to a few millibars by the first stage in order to capture many noble gas molecules of helium and neon. After the pumps of this stage have been saturated, the valves to these pumps are closed and a previously closed valve to a further adsorption pump still containing clean adsorbent is opened so that this pump may pump down the vacuum chamber to the next lower pressure level. This procedure can be continued until the ultimate pressure cannot be further improved by adding further clean adsorption pumps. 

Refer to Exercise 35.) You have begun operation of a pump-and-treat system for the gas station. According to a computer model for conservative solute transport, 1.5 travel times have now elapsed and the capture well should be pumping contaminated water. However, the laboratory reports that your capture well is still pumping essentially clean water, although the pH has dropped from 8 to 7. 

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