Float Valves

A float valve controls liquid level automatically using the buoyancy of a float. As the level in a tank or reservoir rises, the float rises with it and closes the valve; as the level falls, the float drops and the valve reopens to admit more liquid. No external power or signal is needed: the valve responds directly to the level it controls, which makes it a simple and reliable way to maintain a set level in filling and make-up duties.

Two arrangements are common. The direct-acting float valve links a lever-mounted float straight to the closure member and suits smaller bores and tanks. The pilot-operated (modulating) float valve uses the float to drive a pilot that modulates a hydraulically operated main valve, giving smooth, non-slam closure on larger bores and avoiding the pressure surge that abrupt shut-off would cause. Modulating types also throttle near the setpoint rather than snapping shut, which reduces wear and hammer.

Applications include service reservoirs and water towers, break tanks, cooling tower basins, livestock and irrigation supplies and industrial process tanks. The valve maintains the level within a band set by the float travel and by any adjustable pilot.

Bodies are made in cast and ductile iron, bronze, brass and stainless steel, with floats in copper, stainless steel or plastic, in flanged and threaded connections to EN 1092 or ASME B16.5. When specifying, provide the bore and connection, the working pressure and flow, the tank geometry and level band and whether direct-acting or modulating control is preferred, and we can propose a suitable valve.