BMI Surplus Blog

Understanding the Vacuum Pump

In its simplest form, a vacuum pump moves air into or out of something else, much like a sump pump moves water from one area and then dumps it to another. Depending on the design, a vacuum pump can also remove gas and leave behind a partial vacuum. Vacuum pumps also have industrial applications, often used to power equipment or process semiconductors.

How old is the vacuum pump?

Modern versions of the equipment may give an impression that it was an 18th-century invention or later, but its history goes way back. The suction pump, which is the vacuum pump’s predecessor, has been around since the Romans, with the dual-action kind found in the city of Pompeii. By the 17th century, the design of water pumps had greatly improved; along with it is the ability to pull water in increased volumes.

The first vacuum pump was invented in 1654 by Otto von Guericke. His design was later improved by Robert Boyle. The vacuum tube was developed later.

What are the types of vacuum pumps?

Vacuum pumps come in three broad categories, with each one having different subcategories.


Positive Displacement Pump

This type of pump uses a mechanism that continuously expands a cavity, allows gas to flow in from a chamber, seals it off and then exhausts the gas to the atmosphere. It is effectively used for low vacuums.


Liquid Ring Vacuum Pump

Also known as water ring vacuum pump, this equipment is designed to handle air, gas, liquid, water, etc. It is widely used in different industries, including sugar mills, power plants and pulp and paper mills.


Rotary Vane Pump

Invented by Charles C. Barnes of Sackville, this type of positive-displacement pump is made of vanes mounted to a rotor that rotates inside a cavity. It is commonly used as a pressure hydraulic pump, for automatic transmission and power steering.


Piston Pump

As the name suggests, the piston pump uses pistons, which are driven by a crankshaft, to deliver gases at high pressure. Gas enters at the suction manifold, flows into the compression cylinder where it is compressed by a piston that is driven by a crankshaft in a reciprocating motion, and then discharged.

Other examples of a positive displacement pump include a diaphragm pump, scroll pump, screw pump, Wankel pump and lobe pump.


Momentum Transfer Pump

The Molecular pump, as it is sometimes called, uses high-speed rotating blades or high speed jets of dense fluid to kick molecules out of the chamber. It can achieve high vacuums when configured in conjunction with a positive displacement pump, one or two of it in particular.


Diffusion Pump

The diffusion pump was invented by Wolfgang Gaede in 1915, which was later improved by Irving Langmuir and W. Crawford. It is made of a high speed jet of vapor that directs gas molecules in the pump to the bottom of it and out of the exhaust.


Turbomolecular Pump

This equipment works on the premise that gas molecules will gain momentum when continuously knocked against a moving solid surface. This explains why a turbomolecular pump has turbine rotors that spin rapidly.


Entrapment pumps

These capture gas in either its solid or adsorbed state. Although these can be added to a vacuum system to reach ultrahigh vacuums, its operational time is relatively short-lived, even in low or high vacuums. This is because periodic regeneration of the surfaces that trap air molecules or ions is required.


Cryo Pump

If you relate this pump to cryogenic, then your guess is not entirely off. What it does is trap gases and vapors by packing them on a cold surface. Unlike other vacuum pumps, it only works in certain gases. It is cooled by compressed helium and, in some cases, liquid nitrogen and dry ice.


Ion Pump

Also known as sputter ion pump, this vacuum pump can create ions through its negative and positive charges. Under ideal conditions, it can reach pressures as low as 10-11. The Penning trap is a basic element of an ion pump, which is a device where charged particles are stored.


How are vacuum pumps used?

A vacuum pump plays a vital role in many industrial and scientific processes, such as aiding in the molding process of composite plastic and materials.


Production Process

Machines may take the forefront in the manufacturing industry, but some of them rely greatly on a vacuum pump to work. Certain products are also made through such equipment, especially those that require evacuating or refilling with a particular type of gas. Some examples are CRTs, vacuum tubes and electric lamps.

Vacuum pumps also aid in various semiconductor processing, most especially ion implantation. Even the process of moving parts from one end of the conveyor to another requires a pump for better handling. Through to photolithography, a vacuum pump plays a lead role.



In a car’s engine, a vacuum pump can add horsepower, increase its life and keep the oil clean for a longer period. This is why it is a vital part of any high-performance engine. The vacuum pump works by sucking air from the engine, reducing buildup of air pressure that is caused by combustion gases moving past the piston rings in the valley pan. The exhaust is then sent to a breather tank.

A rotary vane pump is also used in automatic transmission and power steering.



Most medical applications that requires suction uses a vacuum pump. The equipment is also employed in radiopharmacy, radiosurgery and radiotherapy


Sewage collection and disposal

Collection of sewage is mostly conveyed by a vacuum system, including low-pressure pumps, grinder pump or through a vacuum sewer, which is composed of an intricate network of pumps. It uses differential pressure between atmospheric pressure and a partial vacuum to allow wastewater to be collected by a central vacuum station.


Vacuum Engineering

What better way to improve the functions of a vacuum pump than through vacuum engineering? But the focus is on innovating equipment and technological processes that use vacuum, especially in vacuum drying, coating and impregnation, glass coloring and antireflecting gas.


These are just some of the applications of this essential equipment, which clearly has many important uses in various areas of daily life.