FDT-25W-Flow-Meter

Supported Applications

The Omega FDT-25W is a wall-mounted, clamp-on ultrasonic flow meter designed for long-term flow measurement in closed conduits. Operating on the transit-time principle, it measures fluid velocity by calculating the difference in sound travel time between upstream and downstream paths using two transducers that function as both transmitters and receivers.

Documented applications include:

• HVAC systems
• Water conservation projects
• Metalurgy processes
• The chemical industry
• Running water monitoring

Operating Conditions & Performance

The FDT-25W is engineered for non-contacting operation, allowing installation on the outside of closed pipes without process interruption. The device supports a wide range of pipe materials including metallic, plastic, and rubber tubes.

• Accuracy: ±1% of reading at rates >0.2 mps
• Repeatability: 0.20%
• Ambient Temperature Range: -30°C (-22°F) to 80°C (176°F)
• Process Temperature Range: -30°C to 160°C
• Humidity Rating: Up to 85% RH
• Response Time: 0~999 seconds, user configurable

The meter accommodates various liquids capable of transmitting ultrasonic signals uniformly, including water (hot, chilled, city, sea), sewage with small particle content, industrial effluent, acids and alkali liquids, alcohol, beer, ultra-pure liquids, solvents, and all kinds of oils.

Configuration Options

The FDT-25W series supports multiple mounting configurations depending on pipe size and liquid characteristics: V-method (sound traverses the pipe twice), W-method (sound traverses four times), or Z-method (transducers mounted on opposite sides, sound crosses once).

Transducer Options

The system is supplied with a standard STD-WS transducer. Additional clamp-on transducers are available to cover specific pipe sizes and temperature ranges:

• Standard Temperature (0 to 90°C):
• STD-WS: DN15 to DN100 (3/4" to 4")
• STD-WM: DN50 to DN700 (2" to 28")
• STD-WL: DN300 to DN6000 (12" to 240")
• High Temperature (0 to 160°C):
• HT-WS: DN15 to DN100 (3/4" to 4")
• HT-WM: DN50 to DN700 (2" to 28")
• HT-WL: DN300 to DN6000 (12" to 240")

Outputs and Connectivity

The meter provides multiple output signal options including:

• RS485 Output
• 4 to 20 mA current loop output
• Totalizer Pulse Output (Frequency)
• OCT output
• RS232/RS485 communication

The device features a powerful recording function capable of storing totalizer data for extended periods up to 5 years. Electrical connections utilize twisted pair lines, and the unit operates on AC/DC power.

Accessories

Supporting accessories include acoustic gels (STDGEL for standard transducers, HTGEL for high temperature), pipe clamps sized up to DN1000/40" (CLAMP1, CLAMP2, CLAMP3), and a 5-meter transducer cable pair (TCH).

Key Product Differences

The primary variation within the FDT-25W series is defined by the selected clamp-on transducer type. Standard temperature transducers are rated for process temperatures up to 90°C, while High Temperature variants extend this capability to 160°C.

• Standard Transducers (STD): Designed for pipe sizes ranging from DN15 to DN6000 across small, medium, and large configurations with a maximum process temperature of 90°C.
• High Temperature Transducers (HT): Match the same pipe size ranges as standard models but are rated for processes up to 160°C.

The FDT-25W unit itself is a wall-mount enclosure with overall dimensions of 210mm width, 251mm height, and 96mm depth. The series does not include wetted materials as the transducers are non-contacting clamp-on types.