Counterbalance and Load-Holding Valve Fundamentals
A counterbalance valve holds a hanging or overrunning load safely and lowers it under control. Without it a cylinder drops if a hose bursts or on valve switching, and the motion turns jerky. This guide explains pre-load pressure, pilot ratio and selection step by step.
View hydraulic valvesHow does a counterbalance valve work?
The counterbalance valve, also called a load-holding or over-centre valve, sits directly on the load-side port of the cylinder. It blocks the return flow until a pilot pressure from the supply line opens it. This creates a back pressure that brakes the load and stops it from running ahead on overrunning or hanging loads. If supply pressure is lost, the valve closes at once and holds the load.
How do I set pre-load and pilot ratio?
Two values decide safe and jerk-free lowering: the pre-load pressure and the pilot ratio. The pre-load should be roughly 1.3 times the maximum load-induced pressure so the load stays held and is not released too early. The pilot ratio sets how much pilot pressure is needed to open the valve.
- Calculate the maximum load-side pressure from area and load.
- Set the pre-load about 30 percent above that value as a reserve.
- For strongly varying loads choose a lower pilot ratio (3:1).
- Bleed the system and verify the setting under real load, not at no load.
What matters for selection and mounting?
Select the valve by rated flow, maximum working pressure and port style. A single-acting stroke needs one counterbalance valve; a double-acting cylinder with loads in both directions needs two valves or a dual counterbalance valve. Mount it as close to the cylinder as possible so a line rupture cannot release the load.
Frequently asked questions
Why does my cylinder judder when lowering?
Usually the pilot ratio is too high or the pre-load is set wrong. The valve then opens abruptly instead of proportionally. Choose a lower pilot ratio such as 3:1 and reset the pre-load under real load.
What is the difference between a counterbalance and a check valve?
A pilot-operated check valve holds the load only statically and opens or closes abruptly. A counterbalance valve opens proportionally to the pilot pressure and actively brakes the load, giving jerk-free and safe lowering.
How high should the pre-load pressure be?
As a guide about 1.3 times the maximum load-induced pressure. That keeps the load safely held without the pre-load wasting energy or making the motion sluggish. Always verify under real load.
Size the right counterbalance valve
Our hydraulics specialists help with pre-load, pilot ratio and rated flow for your cylinder.
Safe load holding
No dropping on hose burst or loss of pressure.
Correct pre-load
Setting values by load and area clearly explained.
Right pilot ratio
Jerk-free lowering through the correct valve choice.
Expert advice
Hydraulics specialists support your sizing.