Pulse-Width Modulated Proportional Flow Control

Responding to the need for affordable microprocessor-controlled digital valves manufactured and readily available in the United States, one manufacturer has designed a pulse-width modulated, two-stage proportional flow control valve for reliable man-in-the-loop control applications such as aerial lifts. The new PWM valve features simple on/off solenoids, no spool drift due to voltage or coil resistance changes, no spool silting or static friction, low leakage of pilot stage at neutral, continuous self flushing, and ease of interface with the microprocessor.