Which valve type is best described as a 4/3-way valve that can regulate flow by adjusting the opening cross-sections proportionally to an input signal?

• A. 4/3-way regulating valve
• B. 4/3-way proportional valve
• C. 4/2-way directional valve
• D. 4/3-way directional valve

Answer: (B)

Proportional flow control in a valve relies on a signal-driven, continuously variable opening rather than fixed on/off positions. A 4/3-way valve has four ports (pressure, tank, and two work ports) and three spool positions, which supports directing flow to a load and returning excess fluid, often with a center or neutral position. When this valve is designed as a proportional valve, the spool position and thus the effective orifice between ports respond proportionally to the input signal, producing a smooth, variable flow that matches the control signal. This lets you precisely set the actuator speed or force by adjusting how open the path is. In contrast, a purely directional valve mainly switches flow paths in discrete steps, and a 4/2 valve (four ports, two positions) typically provides discrete directional control without inherent proportional modulation. So the described valve is a 4/3-way proportional valve.