A Complete Guide to Vacuum Pumps

Ever wondered how to use a vacuum pump? Our complete guide shares everything you need to know about vacuum pumps.

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This easy-to-follow guide will explain everything you need to know about vacuum pumps, including how they work, how they’re used, and the different vacuum pump types available.

What is a Vacuum Pump?

As the name suggests, vacuum pumps are used to create vacuums. These powerful devices pull the gas and air molecules from sealed containers to create a vacuum (technically a ‘partial vacuum’ as it will be imperfect in comparison to a theoretical ideal - or ‘perfect’ vacuum). Such vacuums may be required for an engineering or manufacturing process or they may be used to move liquids from one location to another, just like conventional pumps.

Vacuum pumps are also known as ‘suction pumps’. They are hardworking devices and it is important to ensure they are properly maintained and replaced when necessary.

How Do You Create a Vacuum?

Now we know what a vacuum pump does, it’s time to consider how it works. These ingenious tools induce different levels of pressure in two spaces: high and low. When the regions are linked, air molecules will be pulled from the high-pressure space into the low pressure one, leaving the first empty. In other words, creating a vacuum.

Vacuums can also be created using vacuum generators which work on a venture principle. This is where compressed air passes through a venture chamber designed to move gases or fluids out of a region of space. Venturi or fluid jet vacuum generators rely on the flow of compressed air, gas, or liquid as the ‘motive’ fluid to pull or create a vacuum at the desired port.

Vacuum Pump Applications and Uses

So, what are vacuum pumps used for? There is no single answer to this question as these devices have multiple uses across industry and engineering, including:

  • Semiconductor processing (semiconductors are materials with intermediate electrical conductivity, widely used in the production of electronic components)

  • Composite moulding (composites are materials made from a mix of two or more substances - examples include plywood, fibreglass and reinforced concrete)

  • Uranium enrichment (for nuclear power generation)

  • Oil refining

Vacuum pumps also play an important role in the function of some manufactured equipment, for example:

  • Electric lamps

  • Radiotherapy devices (for cancer treatment)

  • Electron microscopes, spectrometers (for chemical analysis) and similar analytical equipment

  • Air conditioning systems

  • Dairy equipment

  • Gyroscopes for flight instrumentation

  • Automotive engines (to boost braking and increase fuel efficiency)

Vacuum Pump Types

There are four different types of commercially available vacuum pump:

Vacuum Pump Type

Suitable Uses

Positive displacement vacuum pumps

Pumping operations which require a steady speed

Momentum transfer vacuum pumps

Creating powerful vacuums

Diaphragm vacuum pumps

Pumping operations which require a high degree of accuracy

Entrapment vacuum pumps

Storing gas for later release

Let’s take a look at each in more detail.

Positive Displacement Vacuum Pumps

These models combine an expanding cavity at the intake point with a decreasing cavity at the discharge point, allowing for a steady, moderate flow of suction power.

Positive Displacement Vacuum Pumps

Momentum Transfer Vacuum Pumps

Momentum transfer pumps, also known as kinetic pumps, feature a rotating component which propels air or gas from its inlet to its outlet, creating a low-pressure region. When this becomes a vacuum, it is sealed by a powerful valve. Some models also use high-speed jets of fluid to achieve the same result.

There are two types of momentum transfer pumps - centrifugal and regenerative. The former makes use of a centrifuge (rapidly rotating component) to propel fluids through the device. Meanwhile, regenerative pumps (also known as turbine or peripheral pumps) recirculate liquid in order to increase the pressure achieved.

Momentum Transfer Vacuum Pumps

Diaphragm Vacuum Pumps

As the name suggests, these rely on a pair of mechanical diaphragms, which move backwards and forwards to increase and decrease pressure. Liquid backflow is prevented by a valve. Diaphragm pumps are noted for their accuracy and are widely used in industrial environments.

Diaphragm Vacuum Pumps

Entrapment Vacuum Pumps

Entrapment pumps - also known as capture pumps or trapping pumps - are refrigerated devices that induce condensation of air molecules by cooling within a confined space. The resulting liquid is then removed. Some entrapment pumps - called ‘ion pumps’ - use electrical fields to induce condensation.

Entrapment Vacuum Pumps

Vacuum Pump Product Comparison

The following is a selection of leading vacuum pump brands and a snapshot comparison between several products:



Product Example


OVEM-20-H-B-QO-CE-N-1P vacuum generator


Process Diaphragm Pump 5 to 45 L/min

Air Engineering Controls Ltd

Air Engineering Controls Ltd Vacuum Pump


Norgren Vacuum Pump

Vacuum Pump Hazards

Vacuum pumps are powerful and potentially dangerous items. Potential risks include:

  • Contaminated pump oil spillage due to incorrect handling

  • Injury from accidental exposure to moving parts

  • Electrical shocks due to faulty wiring

  • Fire due to overheating or other malfunctions

  • Toxic fumes due to inadequate ventilation

However, the following safety measures will help to minimise risk:

  1. Do not operate pumps in areas of limited or no ventilation

  2. Use a pump or ventilation cabinet whenever possible

  3. Ensure belt guards are in place

  4. Use a spill tray to catch any leakage if faults occur

  5. Ensure tubing is fully compatible with the pump and fit for use - replace it if necessary

  6. Check the surrounding area for any combustible materials

  7. Check switches and cabling for potential faults


What Happens When a Vacuum Pump Fails?

Like all mechanical devices, vacuum pumps occasionally fail. It may be a sudden failure, for instance, the pump refuses to switch on one day, but you are more likely to encounter a gradual accumulation of symptoms as internal issues worsen over time.

Typical symptoms of impending vacuum pump failure include:

  • Oil leakage

  • Noisier operation

  • Smoke discharge

  • A fall in vacuum pressure

What is the Unit of Vacuum?

The pascal (Pa) is a standard international unit of pressure, named after French physicist Blaise Pascal. This is sometimes used to measure vacuums, but the more usual unit is the torr, a term derived from a different physicist - the Italian Evangelista Torricelli.

The torr is defined as equivalent to 1/760th of a standard atmospheric level of pressure. Until recently, a different definition was used: equivalence to a millimetre of mercury in a manometer (pressure measurement device).

What is the Difference Between a Vacuum Pump and a Compressor?

These two devices have distinct purposes. As we saw above, vacuum pumps are designed to create a vacuum through a combination of high and low-pressure zones. By contrast, compressors draw in air from the surrounding environment and compress this by subjecting it to high pressure, creating stored energy for eventual discharge to power pneumatic tools and devices.