Counterbalance valve

Counterbalance valves are used whenever overrunning or negative loads need to be lowered in a controlled manner.

How a counterbalance valve works

To illustrate this, we assume a valve with a total of three ports. The main task of a counterbalance valve is to reduce the movement of cylinders or motors that are supported at the first port. Another port is, for example, connected to a return line or a tank. The valve opens due to load pressure at the first port and pilot pressure at the third port.

The load pressure pushes the piston and inner sleeve against the main spring until the piston reaches the stop. In this position, the load pressure then acts on a small annular area, causing the inner sleeve to be pushed against the main spring. Here, the piston and sleeve separate, with the movement of the inner sleeve additionally supported by the pilot pressure. This pilot pressure then acts on a larger annular area; the ratio of these two annular areas is referred to as the pilot ratio.

Advantages of a counterbalance valve

As described above, counterbalance valves can be used to lower overrunning loads in a controlled manner. During operation, pressure is generated in the inlet and additionally load pressure. This load pressure causes the counterbalance valve to open, and the drive then moves at the required speed.

In summary, counterbalance valves are pressure relief valves that, depending on the pressure applied, ensure that the required speed of the load movement is achieved.

Power losses can be prevented by reducing the counterbalance valve setting via the pressure in the inlet.