Question $[2]$

$[$a$]$ Draw the hydraulic symbols for the following:

Pneumatic compressor$-$ Internal combustion engine$-$ Pressure relieve valve $-$ Pressure regulating valve single acting cylinder.

$[$b$]$ For the control valve shown in figure, Identify the valve work with the different positions.

Question $[3]$

$[$a$]$ The circuit shown in figure is used for drilling a hole in work piece. The sequence operation is a$)$ Clamping of work piece b$)$ Drilling c$)$ Decamping and drill taken out from hole.

$($a$)$ Identify the elements of the hydraulic circuit.

$($b$)$ Redraw the circuit after completing the missing parts. Take into consideration, it is needed to hold the workpiece under pressure after clamping.

$($c$)$ Explain each added element and its role in the hydraulic circuit.

$($d$)$ Modify the circuit to make the drilling attachment return before declamping.