Electric Hydraulic Valve

Types of Electric Hydraulic Valves

Servo Valves

Servo valves are high-end valves used to maximize equipment’s performance. A servo valve has a spool overlap of at least 3% in the center position. This means in proportional valves, the spool slides directly within the cast iron valve housing and in servo valves the spool slides inside a hardened steel bushing.

Pressure and Flow Control and Axis Control Valves

Digital control valves (DCV) offer extended control functionality. They provide axis control (ACV) or pressure and flow control (pQ), and pQ valves have a spool position controller that allows them to adjust the pressure of one axis. Axis control valves are capable of performing position, speed, or force control for one axis, such as a cylinder, on their own.

Electrical and Mechanical Feedback Valves

All proportional and servo valves have closed loop spool position controls, hence spool position feedback is necessary. They employ two kinds of feedback: mechanical and electrical. A feedback spring in mechanical feedback (MFB) valves is compressed by the spool deflection and provides mechanical feedback to the torque motor. Onboard electronics are not required for these valves to function. Electronic position transducers are used by electrical feedback (EFB) valves to determine the spool position. All EFB valves require control electronics to function since this signal is electronically sent back. These valves have electronics built into the design of the valve, negating the need for additional controller cards.

Directly operated valves

In directly operated valves, the spool is mechanically and directly controlled by the actuator. The operating forces have limits to keep the size and expense of these actuators in check. Directly driven valves are restricted to smaller flows and consequently smaller valve sizes since the forces required to move a spool increase with flow and pressure drop. Direct drive valves are powered by a Linear Force Motor.

In pilot operated valves, the primary spool is driven by hydraulics to boost the spool actuation force. Pilot driven valves can achieve very high spool actuation forces by hydraulically amplifying the electrical command signal. Typically, the pilot valve is a smaller, directly actuated valve created specifically to build up large flows.

Nozzle Flapper Operated Valves

Nozzle flapper controlled valves are controlled by hydraulic amplifiers that are activated by a torque motor. Covering a nozzle's opening with a flat plate known as the flapper, the nozzle and flapper mechanism is a displacement-type detector that transforms mechanical movement into a pressure signal. As a result, the nozzle's fluid flow is restricted, and a pressure signal is produced.

It is a widely used mechanical method of building a fluid amplifier with high gain. They were crucial in developing pneumatic PID controllers for industrial control systems and are still frequently used in hydraulic and pneumatic control and instrumentation systems today.

Applications and Benefits

• In blow molding, electric hydraulic valves are used to adjust the wall thickness of the extruded plastic. An electric feedback with a position transducer replaces the role of the mechanical feedback. Integral electronics close the spool's position loop. these valves work well for electrohydraulic position, velocity, pressure, or force control systems with very high dynamic response requirements.
• Fuel flow into a FADEC-controlled turbofan engine is controlled by electric hydraulic valves. The control surfaces of fly-by-wire aircraft are frequently manipulated using electric valves coupled to hydraulic cylinders. A flight control computer that receives commands from the pilot and keeps track of the aircraft's flight controls the signals going to the servo valves.
• There are many different markets and applications where servo and proportional valves are used. From test and simulation tools to offshore and maritime applications, metal forming, wood processing, and plastics machinery.
• Both paper and sheet steel thickness are precisely controlled by valves in paper and steel plants. They regulate all significant and numerous auxiliary operations in plastic injection molding equipment. Additionally, they regulate the process of fuel injection in marine diesel engines as well as the stability of offshore oil drilling platforms in challenging and dangerous conditions.
• Each of these uses calls for precise control over a complicated structure that, in the majority of cases, is exposed to shifting loads that can impair performance.

Choosing the Correct Electric Hydraulic Valve Supplier

To ensure you have the most positive outcome when purchasing electric hydraulic valves from an electric hydraulic valve supplier, it is important to compare several companies using our directory of electric hydraulic valve suppliers. Each electric hydraulic valve supplier has a business profile page highlighting their areas of experience and capabilities, along with a contact form to directly communicate with the supplier for more information or request a quote. Review each electric hydraulic valve business website using our patented website previewer to quickly learn what each company specializes in. Then, use our simple RFQ form to contact multiple electric hydraulic valve companies with the same form.