Simple flow control offers four operating speeds

Feb. 16, 2011

The two, 2-port, 2-position valves in the meter-out circuit shown here provides two independently adjustable cylinder-extend speeds and two independently adjustable retract speeds. Therefore, the operator can select fast or slow extend modes and fast or ...

Richard Schneider

The two, 2-port, 2-position valves in the meter-out circuit shown here provide two independently adjustable cylinder-extend speeds and two independently adjustable retract speeds. Therefore, the operator can select fast or slow extend modes and fast or slow retract modes; each of the four can be set at a different speed.

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This circuit provides four different speeds — two for extension and two for retraction — which can all be set independently. Click on image for larger view.

To illustrate how the circuit works, the flow and signal lines for fast extend are shown in color in the drawing. First, solenoid a of 4-port valve A is energized. This produces slow extend. Then, 2-port solenoid valve B is energized, which results in fast extend.

Note that for fast extend, oil flows through both flow control valves C and D. Thus, the ratio of fast flow compared to slow flow can be quite large.

This circuit was submitted by Henry R. Killian, president of WHL Controls Co. Inc., Houston, and was originally published in the January 1984 issue of Hydraulics & Pneumatics.

About the Author

Richard Schneider | Contributing Editor

Contributing Editor, has been affiliated with Hydraulics & Pneumatics for more than 30 years and served as chief editor from 1987 through 2000. He received a BSME from Cornell University and also completed additional courses at the Milwaukee School of Engineering. His diverse background in industry includes ten years with a fluid power distributor and a variety of other professional positions. He has also been active with the National Fluid Power Association and Fluid Power Society.