# The common terms of vacuum industry

1, What is vacuum? Vacuum system refers to the below atmospheric pressure thin gas state, the region is not an absolute vacuum.

2, What is vacuum?Under vacuum gas rare book degree, usually with “high vacuum degree” and “low vacuum”.High Vacuum degree means vacuum degree”good”, said low vacuum vacuum the meaning of “poor”.

3, Vacuum unit is what? In recent years, international access (Pa) as a unit.Is typically used before (Torr) as the unit.1 holder = 1/760 = 1 mm hg in the pressure of the atmosphere.Joe and his transformation: 1 = 133.322 mpa, or 1 mpa = 7.5 x 10-3

4, Stress or pressure.Gas molecules on the container wall force per unit area, with a “P” said.

5, What is 1 standard atmospheric pressure?, air pressure, the pressure per square centimeter of 101325 dyne symbol: (Atm).

6, what is the ultimate vacuum?Vacuum container after full extraction, stable in a certain degree of vacuum, the vacuum degree is called ultimate vacuum.Usually vacuum container gas must be approved by 12 hours, then after 12 hours of pumping air into vacuum state, the last one hour every 10 minutes to measure time, take the average of 10 times for the ultimate vacuum value.

7, extraction rate.Under certain pressure and temperature, the unit time by the vacuum pump inlet draining gas called extraction rate, pumping speed for short.The Sp = Q/(P – P0)

8, what is the mean free path?As a random thermal motion of the gas particles, successive collision over twice the average distance, with the symbol “lambda” said.

9, what is a vacuum pump flow?Vacuum pump water flow is not, but the amount of gas per unit time through the arbitrary cross section, the symbol with a “Q”, said the unit for t. L/SEC (Pa L/s), or L/SEC (Torr L/s).

10, what is the flow guide?By the ability of the gas flow guide said vacuum pipes.Unit to L/s (L/s), in a stable state, the pipeline flow guide is equal to the pipeline flow divided by the pipe pressure difference on both ends.Symbol for “U”.U = Q/(P2, P1)

11, what is the cold trap (water-cooling panel)?Cold trap is placed between the pump and the vacuum container, used for the adsorption of gas or oil vapor capture device.

12, what role does the gas ballast valve?Mechanical oil seal vacuum pump on the compression chamber to open a small hole, and put on the regulator, and adjust the volume when open the valve, the rotor to a particular location, passed this hole with compressed air chamber to reduce compression ratio, so as to make the most of the steam is condensed from the locked out of the pump with mixed gas in the role of the valve is called the gas ballast valve.

13, what is the vacuum freeze drying?Vacuum freeze drying, also known as sublimation drying.Its principle is to freeze, material to make the containing water turns into ice, and then make the ice in the vacuum sublimation drying and to achieve.

14, what is the vacuum evaporation?In the vacuum environment, heat the material and plating to the substrate is called vacuum evaporation, or vacuum coating.

15, what is the vacuum drying?Advantage of the characteristics of low boiling point under vacuum to the method of dry goods.

Vacuum pump include liquid ring vacuum pump , rotary vane vacuum pump , rotary piston vacuum pump , oil diffusion vacuum pump and so on.

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