What are pneumatic ?
Pneumatics is the technology that uses a gas (usually compressed air) as a way of transmitting the energy needed to move and operate mechanisms . The processes consist of increasing the air pressure and through the accumulated energy on the elements of the pneumatic circuit (for example the cylinders) perform useful work.
In general, the gas used is compressed air, but for special applications, nitrogen or other inert gases can be used.
The basic pneumatic circuits are formed by a series of elements that have the function of the creation of compressed air, its distribution and control to perform useful work by means of actuators called cylinders.
The air is an elastic material and, therefore, when a force is applied it is compressed, maintains this compression and returns the accumulated energy when it is allowed to expand, according to the law of ideal gases
Of course, the pneumatic as such, has its advantages but also has its disadvantages.
Advantages of pneumatics
Pneumatic equipment is increasingly facing competition in the form of mechanical, hydraulic or electrical devices. There are, however, undeniable advantages that will allow you to convince yourself of pneumatic tools and compressed air.
-Easy to transport:
The air is available everywhere and there is plenty of it. The exit air is released into the atmosphere so that there is no need to construct return lines as is the case with electrical and hydraulic systems. Compressed air can be transported over long distances by pipes. It is possible to install central compressed air generating stations and supply them to wear points with a constant working pressure. The energy contained in compressed air can be spread in this way for many applications.
Compressed air can be stored in appropriate tanks. If the tank is integrated in the pneumatic network, the compressor will only operate when the pressure in the tank drops below the critical level. And because there is always a certain pressure reserve, the duty cycle can be completed even when the power supply fails. Portable tanks (on compressors) work well where there is no pipe system required.
-Clean and dry:
Compressed air does not pollute the environment. – in particular oil-free compressors
Pneumatic devices are usually much lighter than comparable electrical devices.
-Safe to use:
The compressed air works perfectly even in environments with high temperature fluctuations or temperatures are extreme. It can be used at very high temperatures, eg for opening the doors of metallurgical furnaces. Devices and pneumatic lines where there is no leakage pose no threat to the system’s safety. Pneumatic devices and their components have a long service life and low failure rate. The pneumatic components are very safe when it comes to the risk of fire, explosion and hazards associated with electricity. Even in places where there is a high risk of such hazards or extreme weather conditions, pneumatic components can be used without the use of expensive safety equipment.
Pneumatic parts are relatively cheaper than hydraulic parts. There is no need to regularly replace components which reduces costs and extends the life of the device.
The principle of operation of pneumatic devices is very simple thanks to which the devices are strong and not susceptible to failures. Parts of pneumatic devices can be easily replaced and the devices can be easily connected and started. Fast media Fast flow rates allow you to quickly complete the work cycle. This ensures short downtime and quick conversion of energy into work. Compressed air can reach a flow rate of over 20 m / sec. Hydraulic applications reach only 5 m / sec. The pneumatic cylinders reach a linear piston speed of 15 m / sec. The maximum controlled speeds for signal processing are in the range of 30 to 70 m / sec in the pressure range of 8-10 bar. At a pressure of less than 1 bar it is possible to achieve a signal speed of 200-300 m / sec.
The flow speed and the force used are fully adjustable.
-Possible applications of compressed air
Compressed air is widely used in all sectors of industry, craft and everyday life.
– It is not explosive, therefore there is no risk of sparks.
– The elements of the pneumatic circuit can work at very high speeds and can regulate quite easily.
– The work with air does not damage the components of the circuit for example by water hammer.
– Changes in temperatures do not significantly affect the work.
-Security: there is no risk
-Speed: compressed air is a fast working medium
-Low viscosity that guarantees low flow resistance, which enables the design of drive systems with high linear speeds (up to 30 m / s)
-low sensitivity and resistance to variable loads (overloaded drive stops)
-high durability and simplicity of handling elements using compressed air in a wide range of operating temperatures with relatively low operating costs
-resistance to the influence of external electromagnetic fields,
Disadvantages of the pneumatics
– If the circuit is very long, considerable load losses occur.
– Special installations are required to recover the previously used air.
– The pressures that are usually worked do not allow large forces and loads to be obtained.
– Quite noisy when unloading the air used from the atmosphere.
-Conditioning: the compressed air has to be conditioned, since it can produce a wear of the pneumatic or mechanical elements.
-Strength: compressed air is economical only up to 20,000 and 30,000 Newtons according to the speed .
-Exhaust air: the exhaust air produces a lot of noise.
-Due to physical properties, the compressed air has the following unfavorable features:
the need to clean air from solid and liquid contaminants,It is necessary to eliminate impurities and humidity (in order to avoid premature wear of the components).
precipitation of water from the air when its pressure and temperature change,
compressibility of the working medium (about 2000 times greater than hydraulic oil)
problems with positioning and simultaneous movement of drive elements
-you are limited by working pressures (up to 10 bar) the range of useful forces and moments
-limited length of linear displacements (working jumps) due to the technical capabilities of the actuators
-high costs of compressed air production and the possibility of leaks in the circuits transmitting the operating medium.
-Exhaust: The exhaust air produces noise.However, this problem has largely been solved, thanks to the development of soundproofing materials.
-Costs: Compressed air is a relatively expensive source of energy; this high cost is mostly compensated by the elements of economic price and good performance (high rates).