Float valve

A float valve responds to liquid-level movement by repositioning a closure or control element to regulate flow into or out of a vessel. The float may act directly on the valve or pilot a separate main valve, so operating behavior varies by design. Unlike an ordinary manual isolation valve, its command comes from the measured liquid level and it can maintain a level or switch between fill limits. Selection should consider inlet or outlet arrangement, required level range, modulating versus non-modulating action, and system hydraulic conditions.