Pneumatics fundamentals are covered in this online script that you can read. A Greek word is where the term “pneumatics” originates from. Originally, the word “pneuma” meant “wind” or “breath,” but it also meant “spirit.” Pneumatics is the term that is associated with the application and utilization of compressed air in the fields of science and technology. Compressed air is utilized in the field of pneumatics for the purpose of doing mechanical labor, controlling components, or transmitting signals.
Compressed air as a working medium
A wide range of technical applications that make use of compressed air as a working medium are included under the umbrella of pneumatics. On the other hand, the working medium in the discipline of hydraulics is described as a liquid. Air that has been compressed was formerly referred to as compressed air. The ambient air is initially drawn in, then compressed with a compressor, then cleaned, and finally utilized for a variety of reasons after going through the process of being processed.
It is also used as active air to move chemicals, such as in painting, or as process air directly in a technical process, such as drying, or as a medium for testing processes, also known as test air. These applications are in addition to the traditional pneumatic applications that are employed in plant engineering. In the field of pneumatics, one of the most essential elements is having a solid understanding of compressed air, including its production, distribution, and application.
The structure of a compressed air system
4 subsystems belong to a compressed air system.
Generating compressed air:
The ambient air is compressed in a compressor after it has been suctioned initially.
Preparation:
Because of the soiled and dust particles that are present in the air as well as the moisture that is there, the compressed air is filtered and dried.
Distribution:
The compressed air is transported to its final destination by means of specialized pipes and hose lines.
Usage:
With regard to its technological applications, compressed air can be utilized in a variety of ways, such as B. as a linear drive, for motors, or as active air for painting work.
Areas of application of pneumatics
Pneumatic systems are used
- In the form of linear drives (cylinders). At this location, components are clamped, expelled, and relocated.
- For switching valves, such as hydraulic valves, the utilization of a pilot valve that operates pneumatically
- Utilizing pressurized air motors for equipment that are used for grinding, drilling, and screwing
- In the nozzles that are responsible for drying or blowing out work
- For Surface coating, e.g. B. for painting by spraying.
Level of pressure in pneumatic systems
Conventional compressed air systems operate at a pressure that is about seven times higher than average atmospheric pressure. The pressure is 6 bars above the normal pressure level (relative pressure). High-pressure networks designed for pneumatic applications with high power requirements operate at pressure levels of up to 18 bar. Special components like hoses and connectors capable of withstanding high pressure are required. In specific systems, such those used for producing PET bottles, the pressure in the compressed air network can reach up to 40 bar.
Advantages of pneumatics
Because they are useful, pneumatic systems are used in machines and processes. Pneumatics often has to fight with hydraulics or an electrical-only solution. When choosing a system, it’s important to know what makes pneumatics better than hydraulics or electricity.
In the end, every technology has pros and cons, so you need to look at each situation individually and decide which option is best. Power, air pressure, and water pressure all work together in a mixed product that is used a lot.
- The speeds and forces of the cylinders are constantly changed or controlled
- Working at very high speeds (up to 1500 mm/s for a normal cylinder, up to 3000 mm/s for a high-performance cylinder, and for engines up to 100,000 rpm)
- In the event of an overload or even a stoppage, compressed air devices usually don’t do any damage.
- Compared to electricity devices, compressed air devices are more simply built. Because of this, they tend to be lighter, which makes work in production easier on the body.
- In pneumatic systems, waste heat doesn’t fall on the spread-out electrical drive units like it does in electrical systems. Instead, it falls on the compressor itself.
- The working medium for electricity systems, like hydraulic oil, costs money. But air, at least in its raw form, is always free to use as the working medium for pneumatic systems.
- pneumatic systems don’t need return lines because the waste air can go straight outside. This makes it possible for compressed air line systems to have simple layouts.
- The hydraulic system’s compressed air tanks are checked on a regular basis to make sure they are safe in case of an explosion.
- The fact that compressed air is not affected by atomic radiation or magnetic waves
- It is possible to store energy in the form of compressed air
Disadvantages of pneumatics
There are many reasons why using compressed air is better than other drive methods. As useful as pneumatics can be, they also have some problems. When choosing between pneumatics, hydraulics, and electricity, it’s important to know what the problems are with each.
- Loss of energy: When electricity is used directly for driving, the energy is much more efficiently used than when compressed air is used. This is because the air in the compressor needs to be compressed with a certain amount of energy. An important amount of the energy is turned into heat. Even though the heat is then recovered, exergy is lost during the process of compressing air.
- Cold: Compressed air motors and other compressor parts that fill up quickly with air cool down while they’re working. They can even get cold.
- Limited forces compared to hydraulic drives: There are limits to the engine forces. The reason is that the pressure at which it works is generally less than 12 bar. It is thought that a 200-mm-diameter piston will produce 21,000 N, which is about 2,100 kg, of force at 7 bar.
- Uniform piston speed requires special technology : One more problem with pneumatics is that you need special seals and throttling technology to make sure that the piston speeds are all the same (sinusoidal cylinder).
- Production of fixed stops required: Since air can be compressed, it is only possible to get very close to a specific place or positions with fixed stops.
- Noise: When compressed air flows out of pneumatic devices, it makes noise. As a defense, silencers need to be planned for.
- Costs: Another problem with pneumatics is that the steps needed to prepare compressed air are hard to understand and cost a lot of money. With the amount of energy used, there is still room for saves.
- The compressed air must be treated: At first, compressed air has dirt and moisture in it. It usually has to be made at a very high cost.
- Oil content of the breathing air: Aerosols can get into the air we breathe, which means there is more oil in the workplace. If newer pneumatic parts don’t use compressed air that has oil in it, this problem won’t happen. So they don’t need any oil at all because they are permanently lubricated. This makes sure that the parts will last a long time. If you can’t stay away from oily air because of current pneumatic systems, you can put oil separators in the exhaust air elements.
- Maintenance and costs: One big problem with gas systems is that they are expensive to keep up. After a certain size, it’s very important to do regular, thorough maintenance because when pneumatic accumulators burst, they release huge amounts of gas, which can be very dangerous, especially in small areas. There is a required checkup that comes with regular extra costs.
- Leaks are difficult to localize: Leaks in compressed air networks are harder or impossible to find than leaks in power lines. A leak can go unnoticed for a long time, which can make energy costs go up by a lot.
