Momentum transfer pump is to rely on high-speed rotating blades or high-speed jet, the momentum transfer to gas or gas molecules, the gas from the pump inlet to the outlet continuously. Specific can be divided into the following types. â‘´ molecular vacuum pump: It is the use of high-speed rotating rotor to transfer energy to gas molecules, so that compression, exhaust a vacuum pump. It has the following types: â‘ traction molecular pump: gas molecules and high-speed rotor collision to obtain momentum, was sent to the exit, therefore, is a momentum transfer pump. Turbomolecular pump: Pump equipped with a grooved disc or rotor with a blade, it is rotating between the stator disc (or stator). The linear speed of the rotor circumference is high. Such pumps usually work in molecular flow conditions. â‘¢ composite molecular pump: It is a combination of turbocharged and towed molecular pump in series a composite molecular vacuum pump. (2) Jet vacuum pump: It is a kind of momentum transmission pump which delivers gas to the outlet by high-speed jet generated by pressure drop of Venturi effect and is suitable for working in viscous flow and transition flow state. This pump can be divided into the following detailed: â‘ liquid jet vacuum pump: liquid (usually water) as the working medium jet vacuum pump. â‘¡ gas jet vacuum pump: non-condensable gas as the working medium jet vacuum pump. â‘¢ steam jet vacuum pump: to steam (water, oil or mercury vapor) as the working medium jet vacuum pump. (3) diffusion pump: low-pressure high-speed steam flow (oil or mercury vapor) as the working medium jet vacuum pump. Gas molecules diffuse into the vapor jet and are sent to the outlet. The molecular gas density in the jet is always low, and this pump is suitable for operation in molecular flow conditions. Can be divided into: â‘ self-purification diffusion pump: pump volatile impurities by mechanical transport to the export without returning to the boiler in an oil diffusion pump. â‘¡ fractionation diffusion pump: This pump has a fractionation device, so that the vapor pressure of the lower working pressure vapor into the work of high vacuum nozzle, and high vapor pressure of the working liquid vapor into the low vacuum nozzle work, it is a more Grade oil diffusion pump. (4) diffusion jet pump: it is a proliferation of pump characteristics of single or multi-stage nozzle with a jet pump characteristics of single-stage or multi-stage nozzle in series consisting of a momentum transfer pump. Oil booster pump that belongs to this type. (5) ion transport pump: it is a gas that will be ionized gas in the electromagnetic field or the role of the electric field, delivered to the outlet of a momentum transfer pump.
