The counterbalance valve, also called a holding valve, is used to prevent a weight from falling uncontrollably. As an example, consider a press with a…
The sequence valve and pressure-reducing valve have some similar features. It is instructive to compare their symbols side by side (Fig. 3.20). Both valves are…
The counterbalance valve and brake valve have similar symbols (Fig. 3.26). The single difference is that the brake valve has a remote pilot line in…
A pressure-reducing valve does not allow pressure downstream of the valve to exceed the set point. Suppose the workpiece must be clamped with two clamps.…
The sequence valve is used to ensure that a certain pressure level is achieved in one branch of the circuit before a second branch is…
There is a type of unloading valve identified as a differential unloading valve. This valve is designed to allow the accumulator to partially discharge before…
In the circuit in Fig. 3.15, the pump builds pressure in the accumulator until the setting of the unloading valve is reached. At this point,…
The symbol for an unloading valve is similar to the symbol for a relief valve except that the pilot line is not connected to sense…
A pilot-operated relief valve can be used to unload the pump at low pressure during periods between work cycles. The schematic in Fig. 3.10 shows…
A pilot-operated relief valve has the same function as a direct-acting relief valve; however, it has a different pressure vs. flow curve. The performance curves…