An OR logic control in pneumatic systems is possible with the help of

Question

Question

This question was previously asked in

ESE Mechanical 2018 Official Paper

Answer 1

OR Function

The single-acting cylinder in Fig can be operated by two different circuits.
Examples include manual operation and relying on automatic circuit signals, that is, when either control valve or control valve is operated, the cylinder will work.
Therefore, the circuit in Fig. possesses the OR function. However, if the output of two 3/2 directional control valves is connected through the port of a triode, the air current from the control valve will be released through the exhaust of the control valve, and so the cylinder will not work.
This problem can be solved by connecting a shuttle valve to the port of the triode. Shuttle valve allows fluid flow from one of two sources just like OR logic. The basic structure of a shuttle valve is like a tube with three openings.