Several people, including you, have used or are using an air compressor for performing a myriad of tasks, ranging right from filling tires to using paint sprayers.
However, do you know how do air compressors work? Probably no, even though you may have seen how they were utilized over the decades. It is sensible to understand how these compressors work and what are the mechanics behind the working of their parts. The latter is undoubtedly more than you may think.
Air compressors work on the basis of compressed air. Due to different mechanisms of compressing air, there are different types of compressors available in the market.
Knowing these details helps you determine the most suitable type of compressor for your tasks. It also helps to understand how effectively you can maintain your compressor. So, read on to dig these details…
The Concept Underlying the Mechanism of Air Compressors
These devices or machines rely on compressed air to operate. This concept of compressed air is basic and easy to comprehend. Here, when air is kept under pressure, it generates energy that a tank can accommodate inside and release it if needed.
This is similar to a balloon releasing the air when being pressurized. This is when the potential energy is transformed into serviceable motion or kinetic energy. By channeling this transfer of energy with the help of air tools (pneumatic tools), you can perform several tasks that were otherwise impossible.
The Main Components
Air compressors are quite simple devices that typically have three primary components. These are:
- Drive as an electric motor or a gas engine to supply power for driving the pump.
- Pump that utilizes the energy from the motor or engine to pull and compress the atmospheric air to high pressure.
- Discharge tube through which the compressed air passes to reach the storage tank.
- Storage tank with a one-way check valve that retains compressed air without putting back pressure on the pump.
This tank performs like an airflow buffer due to which there is no need to operate the compressor incessantly. This results in less motor wear as well as minimal motor damage due to overheating.
Inside the tank, the air is maintained at a pressure higher than that of the air in the room. When you open the regulator, this air is released. This compressed air is then utilized to drive power tools and pneumatic devices.
The air pulled into the tank has water molecules, which do not remain dangling in the air when the pressure is increased at room temperature. Thus, these molecules tend to condense in the tank.
For handling this moisture, there is a drain valve at the tank’s bottom. This is how you drain seized moisture, keep tank corrosion away, and retain tank volume.
Further, air compressors come with a pressure switch that turns the machine ON automatically when the tank’s air pressure is less than the rated ‘on’ pressure. It halts the device when the pressure reaches the ‘off’ pressure. The tank pressure gauge measures the air pressure inside the tank.
When the compressor stops, an unloader valve passes the pressurized air in the tube. As a result, the pump starts without any resistance from the seized air. If the pressure switch, for some reason, fails to stop the compressor, an integrated safety valve then releases the surplus pressure.
Typically, the pressure switch and safety valve are factory set. This ensures safe working. Thus, it is wise not to reset them.
Air Displacement: At the Core of How Air Compressors Work
There are two methods of air displacement, which are at the core of how do air compressors work. For compressing air, the inner parts of a compressor need to move for forcing the air through the chamber to get compressed. The two methods to move the parts are as follows:
- Positive Displacement: This is the commonly used method. In this method, the air is drawn into a chamber where the inner components minimize its volume and compress the air. The chamber opens and closes for the same. When the cycle is over, the air goes into a storage tank. Rotary-screw, piston, and scroll-type air compressors use this method of compressing and storing pressurized air.
- Dynamic Displacement: This is often seen in compressors being used in industrial or commercial applications. This method requires rotating blades on an impeller so that the air is hauled to the chamber, where the moving blades produce energy to build pressure. This mechanism is often utilized together with turbo compressors. You can expect an efficient generation of huge volumes of compressed air. This technology is usually employed in cars using turbochargers.
The Working of Compressor Drives
Drives in air compressors are usually either belt-driven direct-drive structures. In a belt-driven structure, the belt turns with the motor for activating the pump. Unlike the other structure, this one is relatively more affordable and is commonly used across all types of compressors, as the belt is adjustable to changing air demands.
On the other hand, in a direct-drive setup, the motor is affixed to the crankshaft due to which the overall device size is compact. It is also the reason for less maintenance than expected.
While this system is not much adjustable, it is more efficient than the former system due to less loss of power while transferring it to the crankshaft. One more benefit of this system is that it supplies compressed air without first filling the tank.
The Significance of Lubrication
Just like cars and bikes, even air compressors require oil or lubrication for operating smoothly over time. They utilize oil to minimize wear and friction on moving components. These are known as lubrication compressors.
There are also non-lubricated air compressors, which are commonly known as oil-free compressors. Their components are coated using Teflon or other unique materials rather than oil for minimizing friction. Thus, they contain permanently lubricated parts.
However, these compressors heat up faster. Thus, they are not ideal for heavy-duty tasks. Most of these air compressors are seen in industries where manufacturing requires clean air, such as in the food and electronics industries.
You can alose check this video. It perfectly shows how it works. I know that the video quality is only 240p, but still worth watching to understand the basics of how do air compressors work.