SMC VHS40-N04B-Z Single Action Pressure Relief Valve

The SMC VHS40-N04B-Z is a compact, three-port, single-action pressure relief valve with locking holes for lockout/tagout safety and a 1/2 in NPT end style, designed to fit into tight pneumatic enclosures and rugged industrial environments. Part of SMC's VHS series, the valve features an aluminum body and three ports (IN, OUT, EXH) that vent system pressure from the supply line to exhaust when the operating pressure exceeds the device’s relief range, which spans 0.1 to 1 MPa (14.5 to 145 psi). The -Z designation identifies the lock-out variant, providing locking holes that accommodate a padlock for maintenance procedures and helping ensure that the valve cannot be reseated during service. This configuration supports reliable residual-pressure relief in compact pneumatic circuits, actuators, clamps, and machine panels where rapid venting to atmosphere is needed for safe machine reset and safe-state sequencing. The 1/2 in nominal NPT connections align with standard pneumatic fittings, simplifying integration with common tubing and manifolds while delivering repeatable relief performance within its rated range. Designed for industrial automation, it offers predictable, safety-conscious relief behavior as system pressures rise above the setpoint in connected circuitry.