Air Compressor Pump

The air compressor, important equipment in our workshop, helps us finish our tasks efficiently. Now a query may arise is your mind that what makes an air compressor so useful? How does it draw air in so easily and compresses it? Well, there is definitely a working principle behind all this. The air compressor pump is what compresses the air and fills up the tank. Pumps are very useful devices, employed in many fields for their utility.

Let us have a look at the air compressor pump, its working and related terms.


A pump is a device that does mechanical work by moving the fluids- liquids and gases- around on the expense of energy- electrical, manual, wind etc.

Pumps vary in sizes and types; some are single-stage while others may be dual stage. They serve a number of tasks, such as drawing water from well, aeration, fuel injection, pond-filtering etc.

Even an air compressor comes equipped with a pump. This pump serves the task of compressing the air and sending it to the storage tank for its utilization.

A 5hp air compressor pump comes in a variety of make by various manufacturers. It is dual cylinder with either a single or a double stage. The manual lists down the pressure specifications as 175psi, 145psi, etc. The frame is of cast iron and so is the cylinder. Maintenance is made easy by oil sight glass. Pump cooling method is splash lubrication that keeps the pump cool in running condition, too.

The image shows this pump. Run on gasoline engine, it comes with head unloaders allowing the pump to unload while it is in operation. 5hp determines the motor power of pump in horsepower. Such pumps are suitable for replacement air compressor pump.

air compressor pump

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A pump needs a number of accessories to function smoothly. It is good to ensure the proper working of every part to avoid any unwanted situation. If a part needs replacement due to wear and tear or any other damage, visit the nearby hardware store and make the purchase. Some of the air compressor pump parts that you

can replace, in case the need arises, are:

  • Air valve seals
  • Flange
  • Airline connection kit
  • O-ring
  • Air pump muffler
  • Mechanical switch
  • Unloader and relief valves
  • Pump pedestals and mounting bases
  • Pump hose kits
  • Pulsation dampener
  • Shaft seals

The worn out pump parts may continue to work for some time but they create a hindrance in efficient working, consume more energy and generate heat that leads to damaging of air compressor. Hence, it is better to buy high-quality air compressor pump parts once rather than replacing worn-out, low-quality parts several times.


Before I introduce you to a two-stage air compressor pump, you need to know about the single stage pump as well. Now, if a two-stage exists, it is clear there must be a single stage, too.

A brief comparison between the two will make you further clear on the working of both.

The term ‘stage’ determines the number of times the air gets compressed in an air compressor pump. In a single stage pump, air compression happens once, while in a two-stage air compressor pump, it happens twice between the inlet valve and nozzle.


A two-stage pump is slightly different from a single-stage pump in operation.

In a single stage pump, air goes into the cylinder where it undergoes compression in a single stroke; then the compressed air moves towards the storage tank. This air further serves a number of tools that an air compressor can accommodate.

A two-stage pump is commonly known as dual stage compressor pump. The compressed air doesn’t go into the storage tank; instead, a smaller piston compresses it through a second stroke of 175 psi. After cooling it down, the pump sends the air to a storage tank.


A single-stage air compressor is useful for woodworking whereas a 2-stage air compressor pump comes in handy for

  • Metalwork
    • Grinding
    • Ratcheting
    • Shearing
    • Riveting
  • Auto Assembly and Maintenance
    • Greasing
    • Lifting
    • Painting
    • Screwing

A 2 stage air compressor pump powers heavy-duty equipment.


An important point to note is that the number of stages doesn’t mean the number of cylinders. Both, single and dual stage, have two cylinders. However, in the former, both cylinders are of same size, whereas in the latter, sizes of cylinder vary with the second cylinder shorter than the first one. The cooling process in dual stage happens through a cooling tube, connecting the two cylinders. Thus, the air cools down before it undergoes second round of compression.


During the warranted lifetime of the air compressor pump, you may encounter some mechanical fault in your machine and need to replace it. The market offers a number of replacement air compressor pumps to help ease your worry.

However, while purchasing, you must keep in mind certain features like

  • Pressure
  • Capacity
  • Horsepower
  • Motor type
  • Lubrication
  • Duty cycle
  • Cooling
Features air compressor pump

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I have written this article to shed some light on the air compressor pump. I have tried my best to cover whatever there is to the compressor pump. A pump moves around the fluid and in an air compressor, it, specifically, compresses the air. The selection of single/double stage depends on your application; while, woodworking requires a single stage pump, metalwork and more heavy duty work needs double-stage compressor pumps. It is highly advisable that you seek professional help before setting out to replace or fix an air compressor pump yourself. I hope you liked what you read and found it informational. Spread the word forward to your friends. Do comment with your queries and suggestions.



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