Proportional valves

Proportional valves are used when you want to regulate flow or pressure continuously in proportion to an electrical or hydraulic control signal. The valve’s displacement is proportional to the control signal, hence the name of the valve. They are used to control cylinders and motors and are available in normally closed (NC) and normally open (NO) positions. There are also valves with a 3/2 function, which are used to divert flow when the valve is in its neutral, unactuated position.

Simple and user-friendly amplifiers and I/O units

To control the proportional valve function electrically, user-friendly and efficient amplifiers and I/O units are available. This enables more advanced and automated solutions through electronic feedback of parameters such as flow, pressure or temperature, which in turn optimizes the control of hydraulic functions.

Difference between N/C and N/O

The choice between a normally closed (N/C) and a normally open (N/O) valve often depends on how the system is intended to behave in the event of an unexpected power failure. If the function should shut down for safety reasons when power is lost, a normally closed (N/C) valve is preferred. Conversely, if the function should remain active—for example, to prevent overheating in a fan control system—a normally open (N/O) valve is the better choice.

3/2 valves

A 3/2 valve functions as a selector valve and features three ports: one inlet and two outlets. A common configuration involves port 1 (inlet) switching between port 2 or port 3 (outlets). Depending on the valve position, this setup allows pressure and flow to be directed to two different functions—for example, two separate cylinders or actuators. This provides a simple and efficient method of switching between functions in a hydraulic system, without the need for multiple individual valves.

Wide range of applications

Proportional valves are well suited for a variety of applications, such as pressure regulation in hydraulic presses. They are also used in forestry machines, excavators and cranes, where smooth movement and precise positioning of booms and attachments are essential. Other common applications include speed control of hydraulic fans as well as control systems in test equipment and simulators.