SL25GB3-4X/V/12

The SL25GB3-4X/V/12 is a check valve produced by Bosch Rexroth for the Hy-Check Valves series. It is intended to block reverse flow in hydraulic automation circuits while permitting unrestricted passage from port A to port B. A nominal size of 25 defines the internal flow path and assists in matching line dimensions. The threaded connection mounting uses a UNF/UN thread, allowing direct installation into manifolds or pipework. Maximum operating pressure is 315 bar, so the unit handles high-pressure systems without deformation. The cracking action starts when inlet pressure reaches 8.0 bar because code 3 designates this opening pressure. Reverse flow is enabled only after pilot actuation; A→B is free, whereas B→A is pilot-open, supporting load holding. The component uses an FKM seal material to maintain elasticity with common hydraulic fluids, and its layout omits pre-opening features to keep the closing response firm. Control area A1 covers 5.72 cm², establishing the force required to shift the poppet under pilot influence.

Further characteristics relate to pilot control and service logistics. Control area A3 equals 16.61 cm², increasing the available surface for pilot pressure when a stronger opening force is needed. The valve needs 19.27 cm³ of oil to pressurize port X and 17.5 cm³ for port Y, volumes that help size pilot lines and timing circuits. The ratio between the two control areas, combined with the specified oil volumes, provides a predictable differential that supports synchronized unlocking across multiple lines. Pilot oil is returned externally, so designers must route a dedicated drain to tank. Cleanliness must stay at ISO 4406 class 20/18/15 to avoid wear on sealing edges and internal elastomer components. These numerical requirements allow the component to manage stored energy in accumulators or control cylinder motion with a predictable pilot signal that reliably overrides the check function.