FB valves are bypass flow regulators. The flow (and actuator speed) will be largely independent of the load and the pressure conditions. If used to regulate flow from a fixed supply, for example a standard gear or piston pump, the valve will pass the required flow and any surplus flow will be dumped to the tank line at working pressure. These valves find use in motor control with varying loads, cylinder speed control or even steering systems in certain cases (consult Sales department for applications).

A constant flow rate, regardless of system pressures, is established from 1 (Inlet) to 2 (Reg), while a minimum pressure differential exists between the two ports. Input flow supplied to 1 (Inlet) in excess of the regulated output at 2 (Reg) is by-passed to 3 (Tank). Output flow can be varied from closed to the nominal maximum rating for the valve. Reverse flow from 2 to 1 is limited by the selected opening of the restrictor and is not pressure compensated. Reverse flow from 3 (Tank) is not possible.

Line body construction allows direct connection into hydraulic systems. Leakproof adjust screw gives easy, accurate adjustment to required flow setting. Hardened and ground working parts give accurate flow control and long working life.