Model 27N R-DDV pneumatic servovalves from HR Textron, Santa Clarita, Calif., control load position, velocity, acceleration, and force in closed-loop feedback motion-control systems. The servovalves can be used in applications such as testing automotive vehicle components, semiconductor manufacturing, industrial automation, biomedical testing, and lumber processing. They have an 80-Hz frequency response with 10 flow rates from 0.025 to 1.25 Cv.
The servovalves are also suitable for pneumatic applications requiring precise control of force applied to a load. Pressure repeatability is <0.01 psi on 100-psi systems. The valves' rotary direct-drive design controls flow in a single stage, independent of supply pressure. There are no springs, nozzles, filters, or pilot valves. A limited-angle dc torque motor drives the valve spool directly through an eccentric on the motor shaft. An integrated-circuit electronic controller in the valve housing continuously compares input commands with spool position, which is determined by a Hall-effect magnetic sensor.