What is an servo valve?

Servo valves are a close relative of the proportional valve and are based on an electrical torque motor which produces a small deflection proportional to the electrical current through its coil. Andrew Parr MSc, CEng, MIEE, MInstMC, in Hydraulics and Pneumatics (Third Edition), 2011

What are the common problems of servo valves?

Deformation of parts and clearance between them are changed: excessive clearance increases valve internal leakage; too little clearance and the spool and valve sleeve can easily become stuck. Electrohydraulic servo valves are of small size, and components of servo valve are smaller in size, and many of them have special shapes.

Who invented the two stage servo valve with feedback?

Raytheon and Bell Aerospace Corporation from the USA invented the two stage electrohydraulic servo valve with feedback. MIT used a torque motor instead of a solenoid, reducing the power consumed to drive the electrohydraulic servo valve. W. C. Moog invented the two stage single nozzle servo valve in 1950.

What is the magnetic material used in servo valves?

Before the 1980s, the magnetic material of the torque motor in electrohydraulic servo valve was most commonly a nickel-aluminium alloy, which made the output force limited. Nowadays, a rare earth alloy is used as a magnetic material, and this has greatly improved output force.

Why choose an industrial hydraulic servo valve from Parker?

Parker’s range of industrial hydraulic servo valves include directional and flow control valves in manifold-mounted and slip-in cartridge design. Offering a wide choice of functionality, our classic servo valves and DFplus® valves with Voice Coil Drive (VCD®) meet the highest industry demands when it comes to performance and precision.

What is a flapper servo valve?

The servo valve in Figure 4.42 is called a flapper servo and is really the inverse of the jet pipe servo. Here, pilot pressure is applied to both ends of the main spool and linked by orifices to small jets playing to a flapper which can be moved by the electrical control signal.