What is a proportional valve?

Basically defines a valve with a spool in a proportional body design. And it is a continuously variable, electrically modulated, directional control valve with more than 3% center overlap. The function of a proportional valve is to produce a smooth and continuous variation in flow or pressure proportional to the electrical input signal. Connecting the electronics to these valves must be done accurately. These valves allow infinite spool positions and result in infinitely adjustable flow volumes. Infinite spool positioning can be achieved using stroke-controlled actuators that use pneumatic cylinders with proportional valves and solenoids to control the direction and speed of motion. In the hydraulic industry, the term proportional valve refers to a specific type of valve that is very specific to a servo valve. Variable positioning of the valve allows spool design with metering notches for flow control, speed control as well as directional control in one valve. Instead of having separate valves for direction and speed control, another big advantage is when the circuit calls for more than one speed or maximum speed. These different speeds are done by varying the electrical signal level to deliver the current or speed as required. This valve does not require any auxiliary components. These proportional directional valves are controlled or supervised by a DC power supply. Proportional controls used with analog electronic controls will enhance desirable acceleration and deceleration characteristics. It provides a variety of machine cycles that can be safely operated at high speeds, with controlled start and stop features. Regulated acceleration and deceleration results in enhanced machine cycles and production rates. Generally, proportional valves find most of their applications in open-loop conditions. Where pressure and flow are required to change continuously, multiple constant flow and pressure valves can be replaced by a single valve where acceleration and deceleration control is required.