If this option is ordered the hydraulic velocity fuse is installed in the return line of the lift table’s hydraulic circuit. As the lift table starts to lower the hydraulic oil flows out of the lift cylinder(s) and through the velocity fuse to the power unit reservoir. Depending on the model of lift table the velocity fuse is installed directly on the base of the lift cylinder or in a common manifold that monitors the returning oil flow rate from a bank of multiple lift cylinders. Velocity fuses are readily available commonly used and rated in GPM (gallons per minute) of hydraulic flow. For example a 5 GPM rated velocity fuse will allow up to 5 gallons per minute of hydraulic oil to flow freely through the valve without mechanical interruption. In the rare event of a hydraulic line rupture with a loaded lift table in the raised position the hydraulic oil flow rate leaving the lift cylinder(s) will increase both immediately and significantly. If this increased flow rate exceeds the velocity fuse rating an internal valve in the velocity fuse mechanically closes instantly trapping the oil in the cylinder(s) and successfully arresting the downfall of the lift table.
Dec 13, 2019
