Pressure compensator for pressure control directly at the actuator

The pressure compensator is a hydraulic valve that regulates pressure at the actuator. With varying or fluctuating operating pressure, it can keep the pressure at the actuator constant. With constant operating pressure, it can automatically readjust the pressure at the actuator as required.

Pressure compensators are often combined ex works with a measuring orifice. This combination is then referred to as a pressure control valve.

Design of a pressure compensator

A pressure compensator consists of a hydraulic block with at least three outlets. The volumetric flow is routed past a movable piston. The piston is supported by a spring. As pressure increases, the opposing force of the spring also increases. Excess pressure is routed back to the tank via a return line. The pressure routed back to the tank is no longer technically usable, as it would cause undesirable back pressure in the pressure compensator. The pressure downstream of the piston therefore remains constant within a certain range.

In most pressure compensators, the spring force is adjustable. This is done via a manual handwheel or a connection to an electro-hydraulic control system. This can be implemented by an electromagnetic linear actuator as a spool or as a stepper motor.

Applications of pressure compensators

The pressure compensator regulates the output of a specific actuator when pressure in the hydraulic line fluctuates. For example, it keeps the speed of a radial motor constant even when other actuators are connected to the hydraulic system. Pressure compensators are also used for pressure monitoring or for advanced pressure control. For this purpose, the relevant products have one or more ports for connecting manual pressure gauges or pressure sensors for a central hydraulic control system.

Advanced pressure control using the pressure compensator is used in load-sensing systems. They are equally suitable for the open-center system with constant-displacement pumps and for the closed-center system with variable-displacement pumps.

Use of the pressure compensator in hydraulic systems

In complex hydraulic systems with multiple actuators, the pressure compensator is a standard component. Its design is simple but highly efficient. Factors that influence its service life include the spring force of its return spring and the installed seals. Pressure compensators therefore rely heavily on clean, particle-free hydraulic oil. The use of high-performance filters for the hydraulic oil is therefore expressly recommended when using pressure compensators.

Variants of the pressure compensator

Pressure compensators are available for every hydraulic pressure range. They are available in different performance classes. Each pressure compensator has its defined range for which it is optimally designed.

Before use or selection, the line pressure at each installation point of a pressure compensator must therefore be known. This makes a precise and thorough calculation of the entire hydraulic system necessary. Incorrectly used pressure compensators can reduce system performance and wear out very quickly.