How to express the degree of vacuum, what does the degree of vacuum mean?

There are usually two ways to identify the vacuum level:

One is to use "absolute pressure" and "absolute vacuum" (that is, how much higher pressure than the "theoretical vacuum");

In practice, the absolute pressure value of the vacuum pump is between 0. The absolute pressure value needs to be measured with an absolute pressure gauge, and at 20 and 0 above sea level, the initial value of the instrument used to measure the vacuum degree (absolute vacuum gauge) is. (i.e. one standard atmosphere).

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

Relative vacuum"It is the difference between the pressure of the measured object and the atmospheric pressure at the measurement site. Measured with a normal vacuum gauge. In the absence of vacuum (i.e., at normal pressure), the initial value of the table is 0. When measuring a vacuum, its value ranges from 0 to negative).

The "vacuum degree" commonly used in the international vacuum industry is also the most scientific to use absolute pressure to identify; It refers to "ultimate vacuum, absolute vacuum, absolute pressure", but "relative vacuum" (relative pressure, vacuum gauge pressure, negative pressure) is also widely used because of the simple measurement method, the measuring instrument is very common, easy to buy and cheap.

In fact, it is the difference between the relative atmospheric pressure, that is, the gauge pressure.

Absolute atmospheric pressure is relative negative pressure.

1. Vacuum: According to the viewpoint of modern physics, vacuum is not empty, and it contains extremely rich physical content. One way to put it is:

When the pressure in the container is lower than the atmospheric pressure, the part below the atmospheric pressure is called the vacuum, and the pressure inside the container is called the absolute pressure. Another way of saying it is that any space in a container with a pressure lower than the atmospheric pressure is called a vacuum.

There is a difference in the degree of vacuum: when there is no pressure in the container, that is, the absolute pressure is equal to zero, it is called a complete vacuum, and the rest is called an incomplete vacuum. 2. Vacuum:

Vacuum, as the name suggests, is the degree of vacuum. In a given space, the pressure is lower than that of 101325 Pascal, which is a standard atmospheric pressure of about 101 kPa.

Commonly used vacuum units are PA, KPA, MPA, atmospheric pressure, kilogram (kgf cm2), mmhg, mbar, bar, psi, etc. The approximate conversion relationship is as follows:

1mpa=1000kpa

1kpa=1000pa

1 atmosphere = 100kPa =

1 atm = 1 kg (kgf cm2) = 760 mmHg1 atm =

1kpa=10mbar

1bar=1000mbar

Vacuum refers to the degree of thinness of a gas in a vacuum.

If the pressure in the measured device is lower than the atmospheric pressure, a vacuum gauge is required for pressure measurement. The value read from the vacuum gauge is called the vacuum degree. The vacuum value is a value that indicates that the actual pressure of the system is lower than the atmospheric pressure, i.e.:

Vacuum = atmospheric pressure - absolute pressure, absolute pressure = atmospheric pressure + gauge pressure (- vacuum).

Definitions. The degree of gas thinness is usually used"High vacuum"with"Low vacuum"to represent. A high degree of vacuum indicates a degree of vacuum"Okay"Meaning, low vacuum means vacuum"Poor"meaning.

Explain it comprehensively. Vacuum"As the name suggests, it is the degree of vacuum. It is a main parameter of vacuum pumping equipment such as vacuum pump, micro vacuum pump, micro air pump, micro air pump, micro air pump, micro air pump, etc.

So-called"Vacuum", which is a state of gas with a pressure lower than 101325 Pascal (i.e., a standard atmospheric pressure of about 101 kPa) in a given space.

In a vacuum, the thinner of the gas is usually expressed in terms of the pressure value of the gas, and obviously, the lower the pressure value, the thinner the gas.

The correct relationship between the degree of vacuum and the atmospheric pressure and the absolute pressure is: vacuum degree = atmospheric pressure - absolute pressure.

The true pressure of the working fluid is called the "absolute pressure", which is denoted by p. The local atmospheric pressure is expressed in pb, and the absolute pressure is greater than when. When the atmospheric pressure is reached, the pressure value indicated by the pressure gauge is called the gauge pressure, which is expressed by PE: P=PB+PE.

When the absolute pressure is lower than the local atmospheric pressure, the value measured by the vacuum gauge, that is, the value of the absolute pressure lower than the local atmospheric pressure, is called "vacuum degree", which is expressed by PV: P=PB-PV.

Practical Applications:

In engineering, the spring tube pressure gauge is often used to measure the pressure, and the U-tube pressure gauge can also be used to measure when the pressure is not high. At present, more and more electronically used load measuring equipment has entered the engineering field.

Regardless of the manometer, because the load cell itself is under the action of the local atmospheric pressure, the measured pressure value is the difference between the real pressure of the working fluid and the local atmospheric pressure. The value of the local atmospheric pressure can be measured with a barometer, and its value varies with the latitude, altitude and climate conditions of the location.