Pneumatic systems use compressed gas such as air or nitrogen to perform work processes whereas hydraulic systems use liquids such as oil and water to perform work processes. Pneumatic systems are open systems,
exhausting the compressed air to the atmosphere after use whereas hydraulic
systems are closed systems, recirculating the oil or water after use.
A fluid power system uses hydraulics or pneumatics to deliver extremely powerful pushing and pulling forces to machinery. Much of the factory equipment used to lift and move large components is powered by hydraulics. For example, forklift trucks, opencast mining equipment, and multi-purpose agricultural spraying equipment all use hydraulic systems to operate their lifting arms. Pneumatics, on the other hand, are used for a variety of purposes that include delivering power to tools like jack hammers, air guns, and complex industrial equipment for conveying, separating, and air handling goods.
The extensive use of hydraulics and pneumatics to transmit power is due to the fact that properly constructed fluid power systems possess a number of favorable characteristics. They eliminate the need for complicated systems of gears, cams, and levers. The fluids used are not subject to
breakage as are mechanical parts, and the mechanisms are not subjected to
great wear.
ADVANTAGES AND DISADVANTAGES OF
PNEUMATICS
Advantages
1.Pneumatic systems are clean because they use compressed air. If apneumatic system develops a leak, it will be air that escapes and not oil.
2.Pneumatic systems are cheaper to run than other systems.
3.Inherently modulating actuators and sensors.
4.Explosion proof components.
5.High efficiency, example, a relatively small compressor can fill a large storage tank to meet intermittent high demands for compressed air.
6.Ease of design and implementation.
High reliability, mainly because of fewer moving parts Compressed gas can be stored, allowing the use of machines when
electrical power is lost.
7.Easy installation and maintenance.
Disadvantages
1.Low accuracy and control limitation because of compressibility.
2.Noise pollution.
3.Leakage of air can be of concern.
Need for a compressor producing clean and dry air.
4.Cost of air piping.
5.Need for regular component calibration
ADVANTAGES AND DISADVANTAGES OF
HYDRAULICS
Advantages
1.Through the use of simple devices, an operator can readily start, stop,speed up, slow down, and control large forces with very close and precise tolerance.
2.High power output from a compact actuator.
3.Hydraulic power systems can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.
4.Force can be transmitted over distances and around corners with small losses of efficiency.
5.There is no need for complex systems of gears, cams, or levers to obtain
a large mechanical advantage.
6.Extreme flexibility of approach and control. Control of a wide range of speed and forces is easily possible.
7.Safety and reliability.
8.Hydraulic systems are smooth and quiet in operation. Vibration is kept to
a minimum.
Disadvantages
1.Hydraulic systems are expensive.
2.System components must be engineered to minimize or preclude fluid
leakage.
3.Protection against rust, corrosion, dirt, oil deterioration, and other
adverse environment is very important.
4.Maintenance of precision parts when they are exposed to bad climates
and dirty atmospheres.
5.Fire hazard if leak occurs.
6.Adequate oil filtration must be maintained.
APPLICATIONS OF PNEUMATICS
1.Operation of heavy or hot doors
2.Lifting and moving in slab moulding machines
3.Spray painting
4.Bottling and filling machines
5.Component and material conveyor transfer
Unloading of hoppers in building, mining, and chemical industry
6.Air separation and vacuum lifting of thin sheets
7.Dental drills
APPLICATIONS OF HYDRAULICS
1.Machine tool industry
2.Plastic processing machines
3.Hydraulic presses
4.Construction machinery
5.Lifting and transporting
6.Agricultural machinery