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How Does a Vacuum Pump Work

How Does a Vacuum Pump Work

Before we consider the basic working principle of vacuum pumps, it might help to consider what they actually are. So, a vacuum is basically a space that is devoid of substance and matter, which has a gaseous pressure that is lower than atmospheric pressure. Vacuum pumps are an efficient piece of equipment that removes and draws out gas molecules or air particles from a sealed volume. The aim of this process is to leave behind a partial vacuum due to the difference in pressure that is created. Vacuum pumps are designed and manufactured using a variety of technologies, including but not limited to rotary, lobe, screw and liquid ring. This makes them suitable for a large range of different industries and applications.

So, how do they work?

There are different types of vacuum pumps available, but the general working principle is really quite simple and can be broken down into the following steps:

1. Removal of air and gas molecules from the vacuum chamber

This is often done by altering the pressure in the containerised chamber. Scientifically, pressure will try to equalise across connected regions, with gas molecules moving from high to low to fill the entire chamber. Therefore, if you introduce a new low-pressure space connected to the vacuum chamber, the gas molecules will flow and move from the existing high-pressure area (the vacuum chamber) into the low (this area depends on the specific type of vacuum pump) in order to balance the pressure of the two areas. Some vacuum pumps use a more mechanical approach, with vanes and rotors used to push the air out from the vacuum chamber.

2. Compressed air or gas exits into the atmosphere or to the next pump

Depending on the type of vacuum pump or whether it is a two-stage design, the compressed air or gas will leave the system.

3. Creation of a partial vacuum

Once the transfer of air and gas molecules is complete, it will leave behind a vacuum due to the change in pressure achieved. 

When applying this working principle, it’s important to consider the different types of vacuum pumps, whether they are wet or dry, positive displacement pumps which work by mechanically trapping gas and moving it, or kinetic transfer pumps, which work using momentum transfer. As mentioned, some pumps rely on pressure changes, while others utilise mechanical features such as vanes and rotors to push the gas and air molecules out of the chamber. A lot of it is down to your chosen technology! Our team of Air Experts are available to discuss the specifics of your vacuum pump in more detail if you want to better understand your chosen system! 

You can rely on MidTech Air Products Ltd for a variety of high-quality vacuum and blower solutions that offer unmatched performance, efficiency and reliability. For more information about any of the vacuum pumps we stock and distribute, please fill out the contact form below. Alternatively, you can contact us at or feel free to call the Air Experts on 0121 275 2787.

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