Question

1. When the directional control valve in the system below returns to its centre position, the cylinder rod moves in a given direction. Is this direction extension or retraction? During this movement determine the force and velocity. The piston and rod diameters are 3-in and 1-in respectively. The pump flow rate is 2-gpm and the system pressure is 1000psi. REIXA

Answer 1

This centre position is called as Regenerative centre.By using this we can extend and retract the cylinder rod with twice speed with halp of force. When Directional valve is at centre position at that time there is no retraction and extension. I stop at same position.

Velocity of system is 0 as there is no stroke happen during centre position.

Now If There is Extension at that time Force are as follows:

Piston Diameter D1 = 3" So Radius r1 = 1.5"

Rod diameter D2 = 1" so radius r2 = 0.5"

Pressure P=1000 Psi

so Force = P*A1

$F1= 1000* \prod r_{1}^{2}$

F1= 7068.58 Pounds