The vacuum refers to the static gas state with pressure lower than 101325pa in a given space. In the static state of vacuum, the rarefaction of gas state is usually expressed by the pressure value of gas state. Obviously, the smaller the pressure value is, the thinner the gas state is.

There are various types of vacuum pumps in the industry. In view of the fact that the functions of various pumps are inspected by specified test methods, the important coefficients are as follows:

1. Limit vacuum (usually called vacuum): connect the vacuum pump with the test container, put the gas to be measured, and carry out continuous pumping for a long time. When the gas pressure in the container is no longer reduced and maintains a certain value, this pressure is called the limit vacuum of the pump. The smaller the value, the closer to the theoretical vacuum.

2. Pumping rate: at the suction port of the vacuum pump, the volume of gas flowing through in unit time per day.

The volume of traditional industrial vacuum pump is generally very large, and the pump needs special vacuum pump oil and lubricating gasoline, and the medium gas state will contain a lot of oil mist.

With the development of instrument industry and people's requirements for environmental protection, small oil-free vacuum pumps have emerged as the times require

The unit price of the pump is closely related to the vacuum index. Vacuum degree index is an important index pursued by manufacturers all over the world. It reflects the group strength of corresponding machine polishing, sealing skills, material science and other aspects. It is also the key habitual skill for manufacturers to obtain output value. In order to adjust the vacuum index, it is necessary to have a higher sealing premise. Therefore, it is necessary to use more accurate proportion and better material and function components, so that the production cost will be greatly adjusted. And the increase of unit price is far greater than that of vacuum index. Sure enough, the adjustment of pumping rate will also lead to a rise in unit price, but the increase is not large. Therefore, when selecting a small vacuum pump, it is necessary to carefully determine the vacuum index, followed by the pumping rate, so that the best consideration can be given to the use of function and cost.

High vacuum small pump because of the use of very precise sealing parts, so it has higher requirements for the cleaning premise of the working environment, air temperature coefficient, medium composition, etc.

Sensationalism and noise. The higher the pumping rate and vacuum degree of the pump, the greater the sensation and noise.