Standard Grade Technological Studies

Pneumatic components:Cylinders

Pneumatic cylinders

• Cylinders are the muscles of pneumatic systems.

• Cylinders convert the energy stored in compressed air to linear motion.

Pneumatic cylinders

• There are two types of cylinder that we use.

• Single-acting cylinders.

• Double-acting cylinders.

Single-acting cylinders

• A single-acting cylinder requires only one air supply.

• Air pushes against the piston.• This causes it to outstroke.• A fully outstroked piston is said to be

positive. positive

Air in

Single-acting cylinders

• What happens if we stop the air supply to the single acting cylinder?

• The internal spring pushes against the piston.• This causes it to instroke.• A fully instroked piston is said to be

negative. negative

Air out

Double-acting cylinders

• Double acting cylinders have no spring.

• It requires two air supplies…

• They can supply greater forces than a single-acting cylinder.

Double-acting cylinders

• One of the air supplies pushes against the piston.

• Air from the other side is forced out.• The cylinder will outstroke.• Again this is said to be positive...

positive

Air in Air out

Double-acting cylinders

• The second air supply pushes against the other side of the piston.

• Air from the first side is forced out.• The cylinder will instroke.• As with the single acting cylinder, this is said

to be negative... negative

Air inAir out

Actuators

• There are a number of different ways to activate pneumatic valves.

• The most common types are shown below.PLUNGER

PUSHBUTTON

LEVER

ROLLER

ROLLERTRIP

SOLENOID

PILOT AIR

DIAPHRAGM

SPRING

FOOTPEDAL