Pneumatics or Hydraulics

Pneumatics or Hydraulics

Both pneumatics and hydraulics are applications of fluid power. Pneumatics uses an easily compressible gas such as air or a suitable pure gas—while hydraulics uses relatively incompressible liquid media such as oil. Most industrial pneumatic applications use pressures of about 80 to 100 psi. Hydraulics applications commonly use from 1,000 to 5,000 psi but specialized applications may exceed 10,000 psi

Advantages of pneumatics

• Simplicity of design and control—Machines are easily designed using standard cylinders and other components, and operate via simple on-off control.
• Reliability—Pneumatic systems generally have long operating lives and require little maintenance. Because gas is compressible, equipment is less subject to shock damage. Gas absorbs excessive force, whereas fluid in hydraulics directly transfers force. Compressed gas can be stored, so machines still run for a while if electrical power is lost.
• Safety—There is a very low chance of fire compared to hydraulic oil. Newer machines are usually overload safe.

Advantages of hydraulics

• Liquid does not absorb any of the supplied energy.
• Capable of moving much higher loads and providing much higher forces due to the incompressibility.
• The hydraulic working fluid is basically incompressible, leading to a minimum of spring action. When hydraulic fluid flow is stopped, the slightest motion of the load releases the pressure on the load; there is no need to “bleed off” pressurized air to release the pressure on the load.
• Highly responsive compared to pneumatics.
• Supply more power than pneumatics.
• Can also apply many purposes at one time: lubrication, cooling and power transmission.