Operation of a Hydraulic Cylinder Using a 4/2-DC Tandem-centre position Valve

The hydraulic circuit demonstrates the operation of a hydraulic cylinder using a 4/2- tandem-center position directional control valve. The power supply unit includes a fixed-displacement pump that delivers pressurized fluid to the circuit with constant displacement. A pressure relief valve (PRV) can be used to set the maximum/operating pressure [say 200 bar 2900 psi)] in the system.

When the 4/3-DC tandem-center position valve is actuated towards the right, the flow is directed to the piston side port of the cylinder, and the cylinder extends.

When the 4/3-DC valve is brought to its mid-position, the pump flow is bypassed to the reservoir, necessarily at atmospheric pressure, and the cylinder is hydraulically locked.

When the 4/3-DC valve is actuated towards the left, the flow is directed to the piston-rod side port of the cylinder, and the cylinder retracts to its home position.

It may be noted that the cylinder tends to creep with the valve centered. Further, tandem-center valves are not suitable for use in a multiple-actuator system with just one pump, as the pump flow cannot be used for other parts of the circuit independently. However, these valves can be used for the control of a series-operated multiple-cylinder system if the cylinders are required to operate one after another.

For more details on hydraulic circuits, please visit https://jojibooks.com

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By

Joji Parambath

Resource person /Author

Note: This blog series featuring circuit simulation is for those seeking firsthand information on hydraulic circuits.

References:

1. Industrial Hydraulic Systems and Circuits -Basic Level (In the SI Units)

2. Industrial Hydraulics -Basic Level (In the English Units)

About the Author

Joji Parambath is an accomplished expert in Pneumatics, Hydraulics, and PLC with an extensive 25-year background in the field. Over the course of his career, he has trained many professionals from diverse industries, faculty members, and engineering students.

Joji is the primary faculty member at Fluidsys Training Centre in Bangalore, India, offering comprehensive training in Pneumatics and Hydraulics. He has authored an impressive 39 books on the subject matter, all designed to convey knowledge on Pneumatics and Hydraulics in a simplistic and easy-to-understand manner.