Question

In a hydraulic circuit, four double acting cylinders are connected together in the circuit. When a 4/3-way directional control valve (DCV) is actuated manually by using lever, the first and the third cylinder will extend first and followed by the second and fourth cylinder after cylinder 1 and 3 completely extended. When the DCV is shifted to the right envelope mode using lever, the fourth cylinder will retract first, followed by the third cylinder, second cylinder and lastly the first cylinder will retract after the second cylinder fully retract. Sketch the circuit and explain the circuit briefly.

Answer 1

SOLUTION -

S1,S2,S3,S4,S5,S6 - Sequencing Valves

Circuit Operation -

1+ 3+ 2+ 4+ 4- 3- 2- 1-

+ Extension

- Retraction

- Shown position of DCV is neutral position

During Extension -

First cylinder 1 feels , during this oil cannot flows to next cylinder as check valve position.

Then after feeling or full extension of the Cylinder 1 , Pressure in Sequencing valve 1 ( S1 ) is developed and pilot pressure is applied on the pool.

Firstly the sequencing valve is normally closed , now gets opened beacause of pilot pressure.

And thus fluid goes into the cylinder 3 and cylinder 3 now gets extended.

Same happens with the cylinder 2 and 4.

During retraction -

When DCV position is shifted

NOw fluid first directly go to rod end side of the cylinder 4.

then same thing happens again with S4 and its output is directly connected to the cylinder 3 so that after retraction of the cylinder 4 , cylinder 3 gets retracted.

then cylinder 2 and 1 gets retracted.