Question

An embossing press in which a single-acting cylinder is used for ejecting the processed parts, with the help of circuit diagrams, describe how the cylinder can be activated using 2/2 and 3/2 valves. Compare the two diagrams with regard to extension and retraction of the piston rod and draw your conclusions. Also, calculate the advancing pressure (p) for a piston rod whose diameter d = 60 mm and with a load weight F = 5 kN. Ignore the resistances for this calculation.

Answer 1

"Operating single acting cylinder using 2/2 DCV"

In figure we have shown the schematruc diagram of operating direction control valve. As shown in figure when the port open tbe fluid will flow in the cylinder and due to the fluid pressure the piston will go to the right and it will expand.

When the outlet port will open the fluid will go out and the piston will come to left side. Durung this process both port A and valve A will be in closed position.

"Operating of single acting cylinder using 3/3 DCV

In above figure we have shown the schematic diagram of operation of single acting cylinder with 3/3 direction control valve.

When the port will open the fluid will flow from tank port to cylinder by motor pressure due to this the piston will move to right and expand.

In 2nd position the inlet port will close and the tank port will open due to this the fluid will flow from cylinder to tank and the piston will move to right side.

The main advantage of 3/2 direction control valve over 2/2DCV is that in 3/2DCV we can control the contraction movement of the piston where as in 2/2 we can not control the rate of flow.

In 3/2DCV automation of working is easy than 2/2DCV.

Working of the 2/2 DCV is easy.