A safety valve on a hydraulic elevator that automatically closes if the flow rate exceeds a set value, preventing uncontrolled car descent due to pipe or hose failure.
Full Definition
The hydraulic rupture valve — also called a pipe rupture valve or safety check valve — is fitted in the hydraulic line between the pump unit and the cylinder. It continuously monitors oil flow rate. If the rate exceeds a threshold (indicating a burst pipe, hose, or fitting) the valve closes, trapping oil in the cylinder and halting car descent. This prevents the car from falling to the pit in the event of a hydraulic circuit failure. EN 81-2 (now EN 81-20/50 for hydraulic lifts) and ISO 4413 require rupture valves on hydraulic lifts where the car is supported directly or indirectly by a jack.
