Preload valves

The preload valve is a valve with a spring-loaded port. It holds the hydraulic pressure in a system up to a defined level. If the system pressure exceeds this adjustable level the valve will open allow free flow of fluid. The preload valve is used as safety valve to prevent that cylinders extend unintentionally when backpressure is present. It is installed e.g. ahead the ring surface area of the pusher cylinder thus preventing that the cylinder will extend when backpressure is applied to the piston surface area of the cylinder.

Furthermore, the valve can be used as safety feature to prevent cylinder movements caused by the dead weight of the cylinder or due to loss of fluid.