Hedland H681-504 is a precision flow alert flow meter engineered for applications requiring both visual indication and electrical signal output. The 1/2″ NPTH connection provides standard industrial thread compatibility across various fluid systems.
Overview
The Hedland H681-504 combines the accuracy and durability of Hedland’s variable area flow meter technology with an electrical switching function. This flow alert model is ideal for systems that require real-time flow monitoring with discrete electrical signal transmission to controllers, PLCs, or alarm systems. The meter operates reliably in any installation position, making it suitable for fixed piping applications across petrochemical, water treatment, and general industrial facilities.
Key Features
- Electrical Signal Output: Integrated switch provides electrical notification when flow reaches setpoint, enabling automated control and alarming.
- Variable Area Design: Precision-machined piston and metering cone ensure accurate flow measurement independent of viscosity and fluid type.
- Position-Independent Operation: Spring-loaded internal design allows installation in any orientation without measurement degradation.
- 1/2″ NPTH Port: Standard national pipe thread connection simplifies integration into existing piping networks.
- Durable Construction: Built for high-temperature and corrosive environments with corrosion-resistant materials.
- Wide Fluid Compatibility: Suitable for use with oils, water, water-based liquids, and compressed gases.
Technical Specifications
- Port Size: 1/2″ NPTH (National Pipe Thread)
- Flow Meter Type: Variable Area (Rotameter)
- Connection Type: Threaded
- Output: Electrical Signal with Flow Alert Switch
- Operating Pressure: Verify with system requirements
- Temperature Range: Compatible with standard industrial fluid ranges
- Fluid Compatibility: Oils, water, phosphate esters, compressed gases
- Mounting: Inline, any position
Typical Applications
- Pump discharge monitoring in hydraulic and pneumatic systems
- Flow verification in cooling water circuits
- Lubrication system flow monitoring
- Process flow alarms and control feedback
- Fuel and oil delivery system supervision
- Compressed air and gas flow monitoring
Compatibility & Replacements
Compatible With
- Industrial PLC systems requiring discrete input signals
- Standard 1/2″ NPT piping systems
- Hydraulic and pneumatic circuits
- Water treatment and process control systems
- Automotive and heavy equipment hydraulic networks
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. The H681-504 is designed as a flow alert variant within Hedland’s product line and may replace other 1/2″ NPTH Hedland flow switch models with similar electrical output specifications. Consult technical documentation for direct model interchangeability.
Works With
- Industrial control systems and programmable logic controllers (PLCs)
- Standalone relay circuits and timer modules
- SCADA and process automation software
- Standard electrical switch wiring (24 VDC, 120 VAC, 240 VAC compatible)
- Pressure relief and flow control valve networks
