What is a Vacuum Pump?

What is a Vacuum Pump?

A vacuum pump is a device that draws gas molecules from a sealed container in order to leave behind a partial vacuum. The job of a vacuum pump is to generate a relative vacuum within a capacity.

Depending on the working principles, vacuum pumps can basically be divided into two types, namely gas trapping pumps and gas transfer pumps.

As the applications of the vacuum pump extended, the vacuum pump develops into many types. The pumping speed ranges from a few liters per second to hundreds of thousands or millions of liters per second. To facilitate various vacuum processes, several vacuum pumps can be combined as a vacuum pump unit.

Commonly used vacuum pumps include dry screw vacuum pumps, water ring pumps, Roots pumps and vacuum pump units that combine several pumps, etc. These pumps are the main types essential for vacuum processes in various industries in China. In recent years, vacuum pump-related downstream application industries grow rapidly, leading to the fast growth of the vacuum pump industry in China.

1. Liquid ring vacuum pump

The liquid-ring pump compresses gas by rotating a vaned impeller located eccentrically within a cylindrical casing. Liquid (usually water) is fed into the pump and, by centrifugal acceleration, forms a moving cylindrical ring against the inside of the casing. This liquid ring creates a series of seals in the space between the impeller vanes, which form compression chambers. The eccentricity between the impeller's axis of rotation and the casing geometric axis results in a cyclic variation of the volume enclosed by the vanes and the ring.

2. Dry screw vacuum pump

it is a variable volume vacuum pump require no water or oil for sealing or lubrication in the vacuum stages. Thanks to the oil-free, non-contacting screw design, dry vacuum pumps can be safely and reliably used in industries requiring an oil-free, vacuum and clean production environment such as the semiconductor industry, chemical industry, pharmaceutical industry, food industry and so on.

3. Roots vacuum pump

it is a rotary plunger-type pump where two symmetrically shaped impellors rotate in opposite directions inside the pump housing.

General working principle of vacuum pumps

A vacuum pump’s main function is to change the pressure in a contained space to create a full or partial vacuum either mechanically or chemically. Pressure will always try to equalize across connected regions as gas molecules flow from high to low to fill the entire area of that volume. Therefore, if a new low-pressure space is introduced, gas will naturally flow from the high-pressure area to the new area of low-pressure until they are of equal pressure. Vacuum pumps essentially move gas molecules from one region to the next to create a vacuum by changing high and low-pressure states.