air-valves-guide-1

Valve types

CAUTION - Always wear eye protection when working with Pneumatic or Hydraulic systems
Never force compressed air into your skin - this can be fatal!

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Rough Guide to Mechanical Valves

MOVE YOUR CURSOR OVER THE DRAWINGS TO SEE HOW THESE VALVES WORK

Push Button Mechanical Valve

This Micro-switch style mechanical valve is designed as a 3/2 way valve. Its normal mode of operation is:-

De-energised - Pressure port P closed and port A vented to R,which is inside the case and used as a vent only
Energised - Pressure from P is opened to A and R is closed

However if pressure is applied to A it vents to R until the bttton is pressed thus switching pressure to P.
This is shown in the figure to the right and is the mode used for the inflation valve for the simple airmuscle operation scheme we suggested - the deflation valve being as normal.

Proportional "Speed Control" Mechanical Valve

This type of valve is akin to the water control taps we all know well. It allows the flow of fluid to be regulated from zero to the maximum possible through the particular aperture size.
However it differs from a water tap in that it contains a one way bypass valve which allows uncontrolled back flow if the normal output side pressure rises above the supply side pressure.

This can be used to prevent the output side being damaged by over pressuring due to excessive or shock loads on the actuator

.Proportional control of a Shadow Air Muscle

The proportional control of an Air Muscle in inflation and deflation can be achived at low cost using an identical pair of the Speed Control valves and a non-return valve (shown below),

Operation
This requires the inflation valve to be opened to set the inflation speed and closed when the level of inflation desired is reached.

Then the deflation valve may be opened and closed as required thus controlling the speed of deflation and the point of stopping

The non-return valve prevents the air in the muscle from dumping if the supply is switched off.

Non-Return or Check Valve

This valve only allows flow in the direction of the arrow on its case - a fluid diode - since the arrow is the only indication of direction an extra check on the valves orientation before energising the system is strongly advised