What’s the Difference Between an Air Compressor and a Vacuum Pump?

What’s the Difference Between an Air Compressor and a Vacuum Pump?

By on October 12th, 2018 in General

There are many uses for an air compressor and a vacuum pump in many industries. This is why their market continues to grow as well.

However, not many know the difference between the two. This can hinder them from getting the exact machine for their needs.

The truth is that there’s not much difference. Some household machines can even work as both with a few tweaks. Still, it’s important to know their uses and how they operate to find out which one it is you need.

If you’re ready to find out how they differ, dive right in. Learn what’s a pump, a compressor, and what their differences are.

Vacuum Pump VS Compressor

Although vacuum pumps and air compressors may seem similar in principle, there are a few key details that differentiate them from one another. Aside from the main structure, here are the areas where they’re different:

Operation of a Compressor

A compressor usually only transports gas because of the way it works. As the name indicates, it compresses the material, and gas is pretty compressible.

It intakes air from an open environment. It then pressurizes it in a chamber for mechanical or chemical operations. What governs this machine is the compression ratio, the ratio of output to the input pressure.

Can it work with liquids? In most cases, it can’t because a liquid is hard to compress.

An exception may be coffee machines and pressure washers. These compress the water to increase pressure and speed.

Operation of a Pump

A pump uses an engine to transfer mechanical energy to the fluid it’s transporting. It can also move gas like a compressor, but it can also work on liquids as well. Those who want to transport incompressible liquids use a pump instead.

This liquid can contain some solid materials, too. The pump can accommodate liquids of varying temperature, density, chemical content, and more. However, it can be dangerous to transport liquid at its boiling point.

As for air, a pump takes it in from a closed environment. It does so by creating a low-pressure zone in the suction line. As it moves through the pump, there’s no change in volume that occurs.

It can intake from a source higher or lower in height than the pump. It can then transport the fluid to any destination point. The components that govern this process are the suction head and delivery head.

Applications

Vacuum pumps and compressors have several applications, from household to industrial.

In your own home, you’ll find a pump in your washing machine where it drains the water out and into the pipes. Cars have pumps, too, as well as airplanes and ships.

In an industrial setting, companies and factories use pumps for mining, irrigation, air conditioning, flood control, and such. It has also some medical applications such as in Radiotherapy.

As you would expect, pumps have different sizes and volume to accommodate these uses.

As for compressors, some household examples are in your air conditioner and refrigerator. The machine you use to pump air into your tires is also an air compressor. The car itself has a compressor system under the hood, too.

A compressor is also a vital machine in the industrial and medical industries, too. Many use it for oxidation, purge systems, and pneumatic tools.

You’ll also find air compressors in large vehicles like trains, where they may serve as the brakes, and machines like jackhammers, where the pressurized air pushes the drill back and forth.

Other Differences

Some other differences of an air compressor and a vacuum pump are in their power requirements, price, and storage capacity.

In general, a pump uses less power than an air compressor, and it’s much cheaper to purchase. However, it doesn’t have a storage capacity, whereas a compressor can store pressurized gas. A pump only transfers fluids and not store them.

Types of Compressor

Let’s learn more about compressors and pumps, starting with the different compressor types. There are 3 basic types, which you can see below.

Centrifugal

Centrifugal compressors operate using dynamic compression. A rotating impeller produces a high-pressure discharge of air in a process known as dynamic displacement. In order to do this, the machine rotates at higher speeds.

This type of compressor also has a higher capacity because the design allows a continuous flow. Moreover, it’s also an oil-free compressor; the oil-lubricated parts are away from the air flow.

Reciprocating

This type uses a piston within a cylinder, which then pumps air into a chamber until it elevates the pressure. The pressurized air inside stays there until it’s ready for use.

A reciprocating compressor can be single-acting or double-acting. It’s the former when it uses only one side of the piston, and it’s the latter when it uses both sides.

Rotary Screw

This one uses helical straws instead to guide the air into a chamber. It has the highest efficiency among the 3 types, and it’s quieter to operate, as well.

Types of Pumps

Now, let’s move on to vacuum pumps. We can sort them into 2 broad categories:

Positive Displacement

A positive displacement pump moves a fixed amount of fluid and then guiding it into a discharge pipe. This allows the pumps to produce a continuous flow at a set speed regardless of the discharge pressure.

Centrifugal

A centrifugal pump, like a centrifugal compressor, uses an impeller. It accelerates the liquid, which converts the input power into kinetic energy.

A common type is the volute pump, where the fluid enters the eye of the impeller while rotating at a high speed. The fluid accelerates outward, which creates a vacuum at the impeller’s eye. This then creates more suction to draw in more fluids.

Which One do you Need?

Now that you know the difference between a compressor and a pump, you should now also know which one you need. If so, check out our wide selection of machines now.

If you need more help, feel free to visit our blog to learn more. Contact us if you have any questions!