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What is an Air Compressor?

While you probably have heard the name air compressor before, and you may have seen it being used in your car repair shop, you might not know it is such a versatile machine. There are many situations where an air compressor is the best machine for the job. Pressurized air contains a lot of energy that can be used to power all kinds of air tools.

What is an air compressor?

An air compressor is a device that stores pressurizes air in a tank. This pressurized air can then be used to power all kinds of devices like a nail gun, a spray gun for painting, a power wrench, and many more power tools. Other uses are to blow water from pipes if you have to winterize them, cleaning something with the pressurized air. One of the advantages of using power tools that are using pressurized air is that they will have high torque and can be used in locations where electric tools or gas tools can pose a danger.

From a technical perspective, an air compressor is a mechanical device that stores energy in pressurized air. This is done by reducing the volume of the air inside a strong tank. When the air is released, the energy stored in this way can be used to power many different machines.

What can you do with an Air Compressors

Air compressors can be used for many different types of jobs:

  • Air Tools: To power air tools
  • Pneumatic tools: Gives a large amount of moderate-pressure air to power pneumatic tools, such as jackhammers
  • Painting: For air sprayers
  • Tires: To fill all kind of tires
  • Winterizing: To drain water from an irrigation system, or pipes so they can not freeze in the winter.
  • Fill gas cylinders: Supply high-pressure clean air for filling gas cylinders
  • Diving: Supplying air to submerged divers
  • HPA: To fill high-pressure air tanks (HPA)
  • Industry: There are all kinds of industrial processes where high-pressure air is used.

Here you can find air compressors.

Benefits of an Air Compressor

Some of the benefits of using an air compressor and air tools are:

  • Reliable: Air compressors  are more reliable
  • Economical: They are economical
  • Productive: They ensure the growth of productivity
  • Safe: The tool connected to an air compressor does not use electricity, and can be safer in dangerous environments.
  • High torque: They have a higher torque rating

Here you can find air compressors.

Classification of Air Compressor

Air compressors can be grouped according to the pressures they deliver. These include:

  • High-pressure air compressors: These have a delivery pressure above 1000 pounds per square inch (69 bar).
  • Medium-pressure air compressors: They have a delivery pressure of 151 to 1000 pounds per square inch (10.4 to 68.9 bar).
  • Low-pressure air compressors: They have a delivery pressure of 150 pounds per square inch (10 bar) or less.

Methods of Air Compression

There are two major types of air compression. They are the Positive-displacement compressor and the Dynamic compressor.

● Positive-Displacement Compressor

The positive-displacement compressor takes in air and mechanically decreases the space occupied by the air to increase the pressure. Once the highest amount of pressure is reached, a port or valve opens, and the air is delivered into the outlet system from the compression chambers. The positive-displacement compressor is divided into three types which include:

– Piston-type

The piston-type air compressors use the motion of the pistons to pump air into an air chamber. One-way valves are used to guide air in and out of a chamber whose base is made up of a moving piston. During the downstroke of the piston, it pushes air into its chambers.

– Rotary Screw Compressors

They work by matching two helical screws that, when turned, allows air into a chamber, whose volume is reduced as the screws turn.

– Vane Compressors

These make use of a slotted rotor with varied blade placement to allow air into a chamber and flatten the volume. The vane compressor gives a set volume of air at high pressures.

● Dynamic Compressor

Dynamic compressors apply the process of rotating impellers to move pressure to the air. An example of a dynamic compressor is a centrifugal compressor. Compared to other types of compressors, centrifugal compressors spin at higher speeds. They are designed for higher capacity as the flow through the compressor is continuous.

What can you find inside an air compressor

An air compressor is made up of many parts that allow it to function correctly:

  • Motor/Engine: The engine powers the compressor. There are air compressors with an electric engine, and machines that use a gas engine.
  • Tank: The tank contains the high-pressure air. They are normally from metal and in a donut or round shape. These shapes can withstand pressure much better than a box-like shape.
  • Roll cage: The roll cage protects vital parts of the compressor from getting spoilt. A good roll cage should have a low center of gravity so it can’t mistakenly get knocked over.
  • Pressure Switch: When the pressure inside the tank gets to a particular value, the pressure switch shuts the motor down. It also turns it back on when that value goes below a specific point.
  • Air filter: An air filter traps all contaminant particles present in the air. These particles are tiny, but an increase in their concentration can cause spoilage of the compressor, especially if they are filled with moisture.
  • Thermal Overload Protection: For precautionary purposes, some air compressors have a thermal overload protection system. This system involves cutting power to the motor in case the compressor starts to overheat.
  • After Cooler: Airflow is used to cool down the compressor discharge air temperature. This function helps to drop out moisture that is stored in the compressed air.
  • Starter: This is a magnetic device that prompts electricity into the motor windings to strengthen them for work. The starter receives a hint from the pressure switch.

Types of Air Compressor Pumps

There are two main types of air-compressor pumps, namely oil-injected and oil-less pumps. The oil-less system is cheaper, louder, and has a shorter life span than oil-lubed pumps. The oil-less system produces better quality air, and require less maintenance.

● Oil-free vs. Oiled Air Compressor

A dilemma faced by some people is trying to decide on the right kind of air compressor to get. One has to decide between an oil-less or oiled air compressor. Some tips to note when choosing either an oiled or oil-less Air Compressors include:

  • Lubrication: Oiled compressors require frequent oiling while oil-less air compressors do not need any lubrication.
  • Maintenance: Oil air compressors require more maintenance than oil-less ones. This is due to the needed oil change from time to time (although this also depends on the design of the air compressor and the number of times used).
  • Long-lasting: Even though the oil-less air compressors are less expensive, lighter, they do not last as long as well maintained oiled air compressors.

Maintaining an Air Compressor

Like any other mechanical device, it is essential to perform routine maintenance:

● Pump oil level

If your compressor is oil-free, this part of the maintenance is not needed. But you must check the air compressor pump oil level for all other air compressors. When the level is low, it can destroy the pump.

  • Step 1: Turn the machine off. Remove the mains cable if applicable.
  • Step 2: Put the machine on a flat surface, and leave it there for 5 minutes.
  • Step 3: Remove the oil fill cap
  • Step 4: Check the oil level, and see how the oil looks. If it seems dirty, you should change the pump oil.
  • Step 5: If needed, fill with oil. Make sure you do not overfill.

You can find Air Compressor Pump Oil here.

● Change the pump oil

If the oil in your pump is looking nasty or dirty, it needs to be replaced.

  • Step 1: Turn the machine off. Remove the mains cable if applicable.
  • Step 2: Make sure the oil is cooled. If you just used your machine, you have to give the oil some time to cool down.
  • Step 3: Put the machine on a flat surface.
  • Step 4: Remove the oil fill cap.
  • Step 5: Put an oil container underneath the drain cap. You can also use an old bucket.
  • Step 6: Remove the drain plug and let the oil fully drain.
  • Step 7: Put the drain plug back. Make sure it is tightened sufficiently.
  • Step 8: Fill with new oil. Wait a few minutes and recheck the level. If needed, add a little bit again.

You can find Air Compressor Pump Oil here.

● Clean or change the air filter

The air filter cleans the air that the engine uses. Over time it can get dirty or even clog.

  • Step 1: Turn the machine off. Remove the mains cable if applicable.
  • Step 2: Make sure the air compressor is cooled down.
  • Step 3: Remove the filter cover. Normally there are a few screws that need to be unscrewed.
  • Step 4: Get the air filter out.
  • Step 5: Clean the air filter. You can use a vacuum if needed.
  • Step 6: If the air filter looks bad, you should replace it.
  • Step 7: Put the air filter back and reattach the cover.

You can find Air Compressor Air filter here.

● Other maintenance

To further prolong the air compressor’s lifespan, you should also check:

  • Fuel tank: Ensure the compressor fuel tank is clean
  • Shutoff system: Check the correct working of the air compressor shutoff system
  • Nuts: Check the different nuts and bolts and make sure that they are all tight. The shaking of the air compressor may loosen some of them.
  • Vibration: Check for more than usual vibrations or strange noises.
  • Leaks: Check for oil and air leaks
  • Safety release value: Check that the safety release valve is working correctly.
  • Belts: Check the belts for wear and tear
  • Pressure: Check the differential pressure in the compressed air filter
  • Hose: Inspect the hose for damage and wear and tear.
  • Temperature: Check and ensure that the operating temperature does not exceed a safe level
  • Condensation: Drain the condensation from the air compressor tank

● How often should you check and maintain your Air Compressor

How often you should do maintenance on your air compressor differs significantly from your usage. If you use it daily, you have to check things more often than if you only use your machine sparsly.

– Before using your Air compressor:

  • Drain the water from the air compressor tank
  • Check for oil and air leaks
  • Check for more than usual vibrations or strange noises
  • Check the level of the Pump oil

– Monthly

  • Check for loose bolts and nuts
  • Check the safety release valve
  • Check the air filter
  • Belt check
  • Check for air and oil leaks

– Yearly

  • Change the oil in the pump
  • If you have a gas air compressor, give the engine its yearly maintenance

Frequently asked Questions

● How much air do I need?

The most crucial aspect you have to look at when purchasing an air compressor is the amount of air it can deliver. This amount is measured in Cubic Feet Per Minute (CFM). In general, most air compressors can provide between 30 to 140 CFM. If a compressor delivers less than 30 CFM, it is more suited for tire inflation.

To determine the CFM requirement for your air compressor, you can use a simple rule of thumb. Take the CFM requirement for the air tool and multiply it with 1.5. If you do this for all the tools you have or want to use, you know the CFM level your air compressor needs.

Air Tool
Avg. CFM @ 90 PSI
Avg. Operating PSI
Air hammer
90 – 100
Angle grinder
5 – 8
90 – 100
2 – 4
70 – 90
70 – 90
Impact Driver
4 – 12
90 – 100
Spray gun
4 – 8
90 – 100
Inflating tires
125 – 150

● How much pressure is needed?

The air compressor’s pressure is determined by the highest minimum pressure requirement. This can typically be found on the equipment itself or in the owner’s manual. Most air compressors you can buy online or in a shop will pressure between 125 and 175 psi ( 8.5 – 12 bar). The pressure you need will differ from tool to tool but is often in the 80 psi to 130 psi range.

● What size of Air compressor do I need?

The size of the tank depends on what you want to do with it. Filling a bike tire will use less air than a power tool that you will operate continuously. This can be determined by establishing how it will be used. You will find compressors with tanks from 1 gallon to over 50 gallons. The bigger the tank, the longer you can use it before it needs to be filled again.

Here you can find Air Compressors.

● Can air be stored at a higher air pressure safely?

Definitely! The tanks from an Air compressor are designed to store air at high pressure. This is the reason why they are so heavy. When there is a leak, in most cases, it will slowly lose its air, like a car tire.

● How often should the oil be changed?

Depending on the kind of air compressor, it is advisable to check with the equipment technician or manufacturer to find the recommended schedule for the air compressor.

Here you can find Air Compressor pump Oil.

● What is the life span of an air compressor?

Generally, air compressors are very durable goods. With regular and proper maintenance, the air compressor could have a life span of 10 to 15 years.

● Which is better- Oil or oil-less air compressors?

Even though the oil-less air compressors are less expensive, light, and durable, they do not last as long as the oiled air compressors. But they need less maintenance. The one that better suits your need depends on many factors like your budget and your technical skill level. Most cheaper air compressors for home use are oil-less and will be fine for most users.

Final Remarks

This guide provides a basic understanding of what an air compressor is. An air compressor is a mechanical device that changes power into potential energy stored in pressurized air. They are convenient tools that help carry out a variety of jobs. The air compressor can be grouped into Low-pressure, medium-pressure, and high-pressure air compressors. An air compressor is made up of many parts that allow it to function correctly. We have the roll cage, thermal overload protection, air filter, starter, and pressure switch. For the efficient running of the air compressor, daily inspection is required. Things like checking if the oil needs to be changed, ensuring the operating temperature is at a safe level, drain condensation from receiver tanks, etc.

The air compressor can be beneficial in so many ways. They ensure the growth of productivity and are a better option for electric tools. The air compressors are being used by different industries as well as everyday consumers.