The Meaning And Characteristics Of Vacuum

The meaning and characteristics of vacuum

In vacuum science, the term vacuum refers to a state of gas that is below one atmospheric pressure in a given space. This thin gaseous state is often referred to as the vacuum condition. Compared with the atmosphere in which human beings live, this particular vacuum has the following basic characteristics:

(1) The gas pressure under the vacuum condition is lower than in one atmosphere. Therefore, all kinds of vacuum containers on the surface of the earth are bound to be affected by atmospheric pressure, and the pressure difference is determined by the pressure difference between the inside and outside of the container. Since the atmospheric pressure acting on the surface of the earth is about 10135N/m2, when the pressure inside the container is very small, the atmospheric pressure under the container can reach one atmosphere.

(2) The number of gas molecules per unit volume, that is, the density of gas molecules is less than that of atmospheric pressure, due to the thin gas in a vacuum state. Therefore, the number of collisions between molecules, between molecules and other particles (such as electrons, ions, etc.), and between molecules and various surfaces (such as walls) is relatively reduced, which increases the molecular free path of the gas. Table 2 shows the relationship between the mean free path of atmospheric molecules and atmospheric pressure at room temperature.

(3) Due to the decrease of molecular density in the vacuum state, the content of oxygen, hydrogen, and other gases (including the content of water) as components of the atmosphere will also be relatively reduced

IKS PVD company, decorative coating machine, tools coating machine, DLC coating machine, optical coating machine, PVD vacuum coating line, the turn-key project is available. Contact us now, E-mail: iks.pvd@foxmail.com