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Many users are concerned about the vacuum degree of vacuum pump. How to measure and calculate the vacuum degree? The following small series for you to introduce in detail.

"Vacuum degree" is taken out of context as the degree of vacuum. It is a main parameter of vacuum pump, micro vacuum pump, micro air pump, micro air pump, micro air pump and so on.

The so-called "vacuum" refers to the situation that the pressure is lower than 101325 Pascal (i.e. a standard atmospheric pressure is about 101kpa) in a given space.

In vacuum, the degree of indifference of gas is generally indicated by the pressure value of gas. Obviously, the smaller the pressure value is, the more indifferent the gas is.

There are generally two ways to mark the vacuum degree

One is to use "certain pressure" and "certain vacuum degree" (i.e. how much pressure is higher than "theoretical vacuum");

In practice, the pressure of vacuum pump is between 0 and 101.325kpa. At 20 ℃ and altitude = 0, the initial value of the surface used to measure the vacuum degree is 101.325kpa. (i.e. one standard atmospheric pressure)

The other is to use "relative pressure" and "relative vacuum degree" (that is, how much pressure is lower than "atmospheric pressure").

"Relative vacuum" refers to the difference between the measured pressure and the atmospheric pressure at the measured address. Measure with general vacuum gauge. In the absence of vacuum (i.e. atmospheric pressure), the initial value of the table is 0. When vacuum is measured, its value ranges from 0 to - 101.325kpa (generally indicated by negative number).

For example, if a miniature vacuum pump ph2506b measures - 75kpa, it indicates that the pump can pump a vacuum 75kpa lower than the atmospheric pressure of the measurement address.

The "vacuum degree" commonly used in international vacuum work is also the most scientific one, which means "limit vacuum, certain vacuum degree and certain pressure", but "relative vacuum" (relative pressure, gauge pressure and negative pressure of vacuum gauge) is also widely used due to its concise measurement method, wide range of measuring instruments, simple purchase and low price. In theory, they can be converted into each other. The conversion method is as follows:

Relative vacuum = certain vacuum (constant pressure) - pressure of the measuring address

For example, if a certain pressure of a micro vacuum pump vm8001 is 80kPa, its relative vacuum degree is about 80-100 = - 20KPa, (the air pressure of the measurement address is assumed to be 100KPA), which will appear to be -0.02mpa on the general vacuum meter.

The commonly used vacuum units are PA, kPa, MPa, atmospheric pressure, kg (kgf / cm2), mmHg, mbar, bar, psi, etc. The approximate conversion links are as follows:

1MPa=1000KPa

1KPa=1000Pa

1 atm = 100KPA = 0.1MPa

1 atm = 1 kg (kgf / cm2) = 760mmhg

1 atm = 14.5psi swing away

1KPa=10mbar

1bar=1000mbar