Our Velocity Fuse works by sensing flow across a control orifice. When the pressure differential exceeds the predetermined amount (approximately 50 psid), a spring biased poppet will close, shutting flow to the damaged hydraulic circuit.
NOTE: A velocity fuse requires a flow potential large enough to meet the differential pressure setting. Normally, the flow required to trip the fuse is 30% above the rated flow. This is typically done to allow small flow surges just above the fuse rating without tripping the fuse. Flow surges can be caused by sudden start/stops, valve actuations, motor reversals, etc. The fuse allows reverse free flow. Depending on the system requirements, hydraulic fuses may reset automatically when the pressure is removed or with reverse flow.
Refer to Schematic 1 below.