Question

Pneumatics and Hydraulics questions, need an explanation on the answers please.

Answer 1

The answer is option (b).

Explanation for the solution:

a). On becoming fully extended, the piston rod reach position a1 and actuates the roller lever valve, immidiately changing its position. But further the valve is connected to a time delay valve which gives a delay of let's say t₂ ​time intervel before operating next 3/2 valve. Hence the piston can't retract immidiately.

b). When the piston reaches a1, the trip cam actuates the roller lever valve, it further pressurize the time delay valve and hence its reservoir is filled via a restrictor. After a set delay of t₂​, the 3/2 way valve of the time delay valve is switched and it immidiately actuates the main 5/2 way valve, which further actuates the piston to retract.

c). If the button on the directional contol valve is pushed and remain at the same position, then the piston rod carries out a to and fro motion continuously. Only when the valve is returned to its initial position, is the motion sequence concluded at the end.

d). This can't happen immidiately because of the delay caused by time delay valve after the roller lever valve actuates.