What counterbalance valves are used for
Counterbalance are sometimes known as load control or over centre valves.
A common use is supporting crane or excavator bucket loads so that they do not drop when the power is turned off. They also control the load lowering to make sure it is safe and stable.
When machine loads change direction or go over centre then counterbalance valves help control the load while allowing the system to work with a more consistent speed.
A simple way to think of a load control valve is as a pilot operated relief valves mounted on the cylinder port. With no pilot pressure, the cylinder will only move when the pressure exceeds the relief valve setting. When pilot pressure is applied, the pressure at which the relief valve opens is lowered to one that allows safe control.
In reality, counterbalance valves form complex control systems. You can find additional information via the further links section below.
We will be adding a pilot ratio calculator soon.
There are several tips for selecting counterbalance valves in other sections of this site but it can be a case of discussing your application with the valve manufacturer's engineers and perhaps trying different valves in the actual equipment to see which one works best.
Load holding applications are covered by the LOLER regulations whereby every new build or repair needs to be checked that the load does not fall more than a set amount of a given period.