The vacuum range of the high vacuum equipment is 10-2 times the 10-5 power Pa. High vacuum acquisition equipment is generally composed of a number of vacuum units operating in different pressure ranges in series, plus pipelines, vacuum measuring instruments and valves. It is widely used in the fields of electronics, automobile, biotechnology, metallurgy, aerospace and other industries because of its low extraction rate, low pressure and low emission. Commonly used high vacuum equipment is a diffusion pump-based vacuum unit (such as diffusion pump-mechanical pump unit, diffusion pump-Roots pump-mechanical pump unit), a molecular pump-based vacuum unit (such as turbomolecular pump-Roots pump-mechanical pump).
The oil diffusion pump vacuum unit is the earliest vacuum pump unit used in the field of high vacuum. Oil diffusion pump uses low-pressure, high-speed directional movement of oil vapor injection to be pumped into the gas, driving the gas downward movement, will be pumped gas to the exhaust port, so as to reach the exhaust port.
The pumping speed range of the oil diffusion pump is very large, from tens to tens of thousands of litres per second. The limit vacuum is 10-4 to 10-8 power Pa, and the pumping rate is stable in the vacuum range of 10-2 to 10-4 power Pa. Oil diffusion pump is an important pumping device for high vacuum acquisition, which is widely used in vacuum coating, metallurgy and other industries.
KT Series Oil Diffusion Pump
Oil diffusion pump is widely used because of its simple structure, low price, no selectivity to the gas being pumped, high limit vacuum, no mechanical transmission and friction, easy maintenance. The disadvantage is easy to occur oil vapor reflux, resulting in oil pollution in vacuum chamber; long start-up time; high power, relatively power consumption. The return pump of the diffusion pump makes it limited in the use of the vacuum system which requires a high degree of vacuum cleanliness. In order to solve this problem, Yazhreide Machine and Electric usually install cold traps and baffles in the pipes between the vacuum chamber and the main pump inlet of the Hokkaide Vacuum Unit, which can effectively remove the condensate vapor from the vacuum chamber and the reflux oil vapor from the steam flow pump.
The vacuum unit with molecular pump as the main pump is also known as an oil-free vacuum unit. Although molecular pumps are mechanical pumps, they are also different from mechanical pumps. The mechanical pump is a volumetric pump by changing the volume of the pump chamber, and the molecular pump is a rigid body in high-speed rotation, its momentum to the gas molecule, so that the gas molecule has a directional speed, and then compressed, and finally through the exhaust port.
FB Hybrid Molecular Pump Turbo Molecular Pump
Turbo molecular pump is pumped through fixed blades and high-speed rotating blades. In the past two decades, molecular pumps have been widely used in various industries, especially in thin film industry, semiconductor microelectronics industry and high-tech industries, because of their advantages of clean and high vacuum. Moreover, the molecular pumps produced abroad can be directly pumped from the atmosphere to high vacuum, without the need for a combination of pre-pump.
The molecular pump has a fast start speed and can effectively improve work efficiency. But because the molecular pump is pumped by mechanical movement, the wear between the rotating blades is aggravated after a long period of use, which greatly reduces the service life of the molecular pump. Moreover, the molecular pump has limited gas extraction and is not suitable for pumping heavy steam and other heavy gases.