Hydraulic proportional valves - A solution for every problem

A hydraulic proportional valve is a valve that uses a proportional solenoid (or servo) to enable both direct switching positions and a stepless transition between them.

They are particularly suitable for applications with changing volume flows and pressures. As proportional valves allow the flow rate to be changed dynamically, they are used when the exact amount of fluid required is not known in advance. The same applies to changing pressure conditions.

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Hydraulik Proportionalventile verschiedener Bauarten

What is the difference between proportional and servo valves in hydraulics?

Proportional valves hydraulics are more robust than servo valves with reduced accuracy requirements. Proportional valves are also considerably cheaper. Furthermore, proportional valves have the same connection diagram as classic directional control valves (CETOP). In addition, hydraulic proportional valves are also available as screw-in valves for intermediate plates, end plates and pipe housings. A hydraulic control block can be used to implement a wide variety of applications individually and effectively.

Function of the proportional valve – stroke-controlled solenoid

For proportional valves, stroke-controlled solenoids are mainly used in hydraulics. The position of the armature is regulated by a closed control loop and maintained independently of the counterforce. The prerequisite is that the counterforce is within the permissible operating range of the solenoid.

Stroke-controlled solenoids can be used to directly actuate the pistons of directional control and throttle valves and move them to any desired position. With pressure valves, the spring can be preloaded and thus the pressure can be adjusted electrically.

Hydraulic proportional valve – simple control

Hydraulic proportional valves are controlled by an electronic control unit. Our control modules from WEST-Elektronik are designed so that simple parameterization can be carried out without programming knowledge.

Our control modules can be used to control hydraulic proportional directional control valves, flow control valves and pressure control valves.

Beispielregelkreis proportionale Ansteuerung Hydraulikzylinder

Beispielregelkreis zur proportionalen Ansteuerung von Hydraulikventilen.

Types of proportional valves in hydraulics

Pressure proportional valves | Hydraulics

Pressure proportional valves allow any number of pressures to be set by electrical preselection. With pressure valves, the electrical input signal causes a proportional deflection of the solenoid armature and pretensions the compression spring. This changes the pressure setting.

The pressure is normally recorded by a pressure sensor/pressure transmitter and fed back to the control electronics. This ensures that the magnet moves to the preselected position and maintains it.

There are both proportional pressure control valves and proportional pressure relief valves.

Directional proportional valves | Hydraulics

Directional proportional valves allow the direction and speed of hydraulic cylinders and hydraulic motors to be changed. The spool stroke is proportional to the electrical input signal. Basically, hydraulic directional proportional valves are a further development of a conventional 4/3-way, 4/2-way switching valve (black/white valve). The valve is controlled by stroke-controlled proportional solenoids. The armature plunger acts directly on the spring-centered valve spool.

The valve spool is continuously positioned in an electrical control circuit. The solenoid armature is connected to the valve piston. The position of the slider is detected by an inductive position sensor and fed back to the control electronics; alternatively, this can also be done by a pressure sensor or volume flow sensor. The valve spool is held in the predetermined position by the electrical input signal.

Proportional directional control valves are available in many versions, e.g.: 4/2 and 4/3 directional control valves, 2/2 and 3/2 directional control valves and many more.

Proportional flow control valves | Hydraulics

In a 2-way or 3-way flow control valve, the proportional solenoid is used to adjust a throttle by means of an electrical signal. With proportional flow control valves, the stroke-controlled solenoid acts directly on the throttle element. Thanks to an integrated pressure compensator, the set value is kept virtually constant even under changing load conditions. Various control ranges enable precise adaptation to the application.

Typical applications are the speed adjustment of hydraulic motors and the infinitely variable adjustment of cylinder travel speeds. Further applications can be realized individually.

Proportional throttle valves | Hydraulics

A proportional throttle valve changes the opening cross-section in the valve by adjusting the current of the proportional solenoid. This is similar to a mechanical throttle valve by adjusting the throttle screw.

Different opening cross-sections are usually available, allowing both large volume flows and small volume flows to be precisely controlled. What is important with this type of proportional throttle valve is the resolution requirement, which determines how “fine” the volume flow can be set.

Examples of proportional valves in hydraulics

Proportional 4/3-way valve

Proportional Druckregelventil PPD-11A, Zwischenplatte (WINNER HYDRAULICS), Leistungsverstärker PAM-190-P-I, Druckregelmodul MDR-133-U (WEST Elektronik).

Proportional pressure regulator in intermediate plate with power amplifier (PAM-190-P) and pressure regulator module (MDR-133)

Proportional flow control valve in pipe power housing

Proportional pressure relief valve (screw-in valve)

Proportional throttle (screw-in valve)

Are you looking for hydraulic proportional valves and solutions for controlling the valves? We will be happy to advise you!

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