The vacuum knowledge

The vacuum knowledge

First, the basic concept of vacuum
Vacuum technology, the "vacuum" refers to a given space, the gas pressure is below atmospheric pressure gas state, that is to say, compared with the normal atmospheric pressure, a gas is relatively lean state.
　The degree of vacuum is an objective measure of the degree of lean gas. According to the theory of vacuum technology, the vacuum level is usually represented by gas pressure. In the International System of Units, the pressure is Pa (Pa) as a unit 1Pa = 1N / m2. Another common unit as well as child care (Torr), millimeters of mercury (mmHg), millibar (mbar), engineering atmospheric pressure (kg / cm 2).
　Divided vacuum region is no uniform requirement, it usually is divided country:
Rough vacuum: (760 to 10) Torr
Low vacuum: (10 to 10-3) Torr
High vacuum: (10-3 to 10-8) Torr
Ultrahigh vacuum: (10-8 ~ 10-12) care
XHV: 10-12 Torr
　Relations care and Pa: 1 Torr = 1 mm Hg (mmHg) = 133.322Pa, 1 Pa = 7.5 × 10-3 Torr.
　Features vacuum region of their different applications are different, such as vacuum cleaners work in rough area, thermos bottle, light bulbs and other work in the low vacuum region, while the vacuum switch and some other vacuum devices are working in a high vacuum region.All of the vacuum pressure need the vacuum pumps,or vacuum system to reach,such as rotary vane vacuum pump,liquid ring vacuum pump,rotary piston vacuum pump,dry scroll vacuum pump and so on.