Lee shut-off valves function as normally-open check valves used to shut off flow under specified conditions. We offer two types of shut-off valves – bypass valves and flow fuses. Bypass valves are hydraulically piloted to shut off the flow, while flow fuses shut off flow when the flow rate through the valve reaches a defined limit.
Flow fuses are found throughout critical hydraulic systems. In the event of a system breach, the fuse will sense an increase in flow rate and shut off, preserving hydraulic power and functions upstream of the fuse. A flow fuse can also function as a vent valve to purge trapped air or vapor out of a fluidic system, such as a fuel system during engine start-up.
Lee shut-off valves are known for their miniature size (which helps save weight and space in critical applications), easy installation, and precise, reliable performance. Read our Tech Talk for Engine Shut-Off Valves to learn more.
Known for their durability, longevity, and small size, Lee bypass valves are designed to shunt flow across an actuator piston when the system pressure is either shut off or lost. They are normally open, with a hydraulically actuated pilot-to-close feature. These stainless steel valves are available in a 0.375 inch diameter insert for system pressures up to 4000 psi, have a maximum restriction of 70 Lohms when fully open, and weigh only 16 grams each. Similar to Lee shuttle valves, Lee bypass valves include a polyimide compression seal to ensure there is no external leakage across the three-port design when properly installed.
Lee flow fuses are individually designed to meet custom requirements. The valve design functions as a normally open check valve. As the flow rate increases beyond a specified value across the valve, a poppet shuts against the valve seat and stops the flow. Valve materials are typically stainless steel but can be tailored to specific requirements. Lastly, our flow fuses are suitable for system pressures up to 15,000 psi.
Insert-style flow fuses are available in 0.187, 0.281, and 0.375 inch diameters with the fused flow direction available in forward and reverse. Cartridge-style flow fuses are available in 0.295, 0.483, 0.798, and 0.989 inch diameters. A zero leak version using an elastomeric seal is also available.
Partner with The Lee Company and get much more than just a supplier of top-quality fluid control products. Our reliable technical support team is available every step of the way to help you find solutions, maximize productivity, and drive efficiency across your operations. Check out these aerospace and defense-specific resources to learn more.