Pneumatic circuit

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A pneumatic circuit uses compressed air to do work. It usually needs a compressor or an air tank.

Key parts
- Cylinder: can be single-acting (one air port; air pushes to extend, a spring returns) or double-acting (two ports; air pushes to extend and retract).
- Direction control valve: steers the air where it should go. They can be normally open (NO) or normally closed (NC). Valves are named by ports and positions, such as 2/2, 3/2, 5/2, or 5/3.
- How valves are operated:
- Two-pressure valve: two buttons must be pressed at the same time to let air flow, keeping hands away from the machine.
- OR valve (shuttle valve): pressing either button allows air flow.
- Check valve: air can flow in only one direction.
- Quick exhaust valve: a type of OR valve with a fast exhaust to speed up the cylinder’s return.

Other important parts
- One-way flow control valve: a throttle valve combined with a check valve to slow movement in one direction and speed it up in the other.
- Time delay valve: combines a 3/2 valve, a reservoir, and a flow control valve to delay activating the cylinder after a button is pressed.
- Pressure relief valve: prevents the system from building up too much pressure by venting air if it gets too high.