Overview
The Humphrey 250A N/O 21 is a compact, air-piloted directional control valve from the proven 250A series. This air control valve operates on the classic Humphrey diaphragm poppet principle, delivering reliable 2-position switching with minimal maintenance. Ideal for OEM and replacement applications in pneumatic automation systems, the 250A N/O 21 offers dependable performance in production and test environments.
Key Features
- 3-way, 2-position directional control with normally-open (N/O) configuration
- Air-spring return design ensures positive shifting and bubble-tight sealing in both actuated and unactuated states
- Compact inline mount design permits close-proximity installation to work zones
- 1/4″ NPT port connections for standard pneumatic systems
- Fast cycling and quick exhaust for responsive system control
- Optional brass body construction available for alternate media compatibility
Technical Specifications
The Humphrey 250A N/O 21 is engineered for robust pneumatic applications with the following characteristics:
- Function: 3-way, 2-position directional control valve
- Configuration: Normally Open (N/O)
- Actuation: Air-piloted (pressure-operated)
- Return Type: Spring and air-spring return
- Port Size: 1/4″ NPT
- Mounting: Inline
- Core Technology: Diaphragm poppet principle
- Body Material: Standard or optional brass (for alternate fluids)
Typical Applications
The Humphrey 250A N/O 21 serves critical roles in pneumatic automation:
- Pneumatic actuator control (cylinders, air motors)
- Air pilot stage for larger directional valves
- Pneumatic machinery and production equipment
- Test and measurement system control
- OEM equipment and retrofit applications
- Fast-cycle automation where responsiveness is essential
Compatibility & Replacements
Compatible With
- Standard 1/4″ NPT pneumatic systems
- Air pilot-operated control circuits
- Pressure-regulated pneumatic supply networks (refer to Humphrey specifications for pressure ratings)
- Inline cavity and manifold mounting blocks designed for 250A series
- Pneumatic automation platforms using diaphragm-poppet valve technology
Replaces / Drop-In Replacement For
The Humphrey 250A N/O 21 is a direct replacement for equivalent 250A-series normally-open 3-way pneumatic valves in the same port and pilot configuration. Verify compatibility with your system integrator before ordering to ensure identical port orientation, pilot pressure requirements, and media compatibility.
Works With
- Humphrey Series 250A pneumatic components and manifolds
- Standard pneumatic system design software and schematic tools
- Air preparation equipment (filters, regulators, lubricators)
- Pneumatic actuation devices (double-acting/single-acting cylinders, rodless cylinders)
- Pressure gauges and monitoring systems rated for industrial pneumatics
