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How Air Compressors Work: The Basics

air compressors

Air compressors play a vital role in any auto shop. They’re multifaceted tools with a host of functions and learning how to use an air compressor properly can save you a lot of time and hassle.

What is an Air Compressor Used For?

Air compressors can be used for welding, plasma cutting, pneumatic robot operation, and tire inflation. They help drive machines that lift, move, position, and fasten vehicle parts. Air compressors are also useful for body painting, high-pressure cleaning, and washing.

How Do Air Compressors Work?

How does an air compressor work? An air compressor pushes air into a container, pressurizes it, and then pushes it through an opening where it builds up until it’s ready to be used. When air is released, the energy from the pressurized air changes into kinetic energy that can power a range of tools.

What Is Air Displacement?

Now that the question of “how does an air compressor work?” has been answered, it’s time to cover air displacement. This is the measure used to determine the volume of air a compressor can move in a single stroke. It’s measured in cubic feet per minute (CFM) or liters per second (l/s).

To find the air displacement level of your compressor, multiply your air compressor’s tank size by the maximum PSI on your tank’s gauge to find the tank’s size in cubic inches. Next, divide the product by 1,728. Your answer is your compressor’s CFM rating.

Types of Air Displacement and How They Work

Air compressors fall under two main categories. These are positive displacement air compressors and dynamic (also known as non-positive) displacement air compressors.

Positive Displacement

Positive displacement air compressors work by forcing air into a chamber. The chamber then gets smaller, which decreases air volume and compresses the air. Piston, scroll, and rotary vane air compressors are all positive displacement air compressors. Positive displacement air compressors are the ones typically used in auto shops.

Dynamic (non-positive) Displacement

Dynamic displacement air compressors have a rotating blade that generates airflow, which is then restricted to create pressurized air. Axial and centrifugal air compressors are both dynamic air compressors. Dynamic air compressors are typically found at manufacturing and chemical plants.

Single Stage vs Two Stage

There are two types of piston air compressors. These are single-stage and two-stage.

Single-stage air compressors compress air on one side of the piston. The air is only compressed once, after which it is delivered to the tank, where it’s held until it needs to be used. These air compressors are one of the more affordable options and are commonly used by most auto mechanic shops.

Two-stage air compressors compress air twice. The air is compressed once before it moves into the tank. In the tank, the air is cooled and compressed again. Two-stage air compressors tend to have higher air pressure levels than single-stage air compressors.

Components of an Air Compressor

All makes and models of air compressors have the same basic parts. One of the most important parts is the electric motor. The motor powers the device to enable it to compress air and then release the compressed air as needed. The pump pressurizes the air before sending it to the storage tank. The storage tank stores the compressed air until it’s ready to be used.

The pressure switch controls the motor and will shut the motor off automatically if the air pressure in the tank reaches its limit. The intake filter prevents dirt and debris from entering the compressor while the exit filter cleans the compressed air as it leaves the tank. Pressure gauges on the air compressor will help you see the pressure levels of the air inside the tank and the air coming out of the air hose.

Air compressor parts need regular maintenance so the device will work properly. If parts become worn, you should replace them right away to prevent damage to the entire machine. A broken tank is best replaced rather than repaired, and it’s important to choose a tank with care to ensure it’s the right size, air pressure rating, and horsepower rating for your device. You’ll also want to choose filters with care to ensure they’ll meet your exact needs. Take your shop environment, air compressor operating temperatures, pressure drop, and other factors into account to ensure the filters will be able to keep the air compressor and compressed air clean and particle-free at all times.

How Lubrication Works in Air Compressors

Lubricated air compressors need oil to keep all moving parts working properly. How the oil is distributed varies depending on the compressor type, but most lubricated air compressors store oil in a reservoir. This oil is then drawn via pumps to feed the various compressor components. Once the oil has lubricated the compressor, it drains back into the reservoir.

Oil-free air compressors, on the other hand, may use water in place of oil to keep the compressor running as it should. However, some models need no lubrication as they are designed to prevent metal parts from coming in contact with other metal parts.

Air Compressor Power Ratings

Experts use three main ratings to determine an air compressor’s power levels. CFM shows how much air a compressor can produce. PSI, which stands for pounds per square inch, indicates the amount of force the device can deliver. Horsepower (HP) measures the amount of work your compressor’s motor can perform.

SVI: The Leading Air Compressor Parts Provider

Keeping your air compressor running smoothly prevents delays and enables you to do your job faster and more easily than would otherwise be possible. That’s why it’s important to work with a reliable parts supplier that can provide the exact components you need to keep your air compressor in tip-top shape at all times. SVI International has over 40,000 products for sale and two ready-ship warehouses offering same-day shipping to ensure all orders are processed without undue delay. Contact us to find out more about our products and services, or to place an order for the air compressor parts of your choice.

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