The Pulsar Measurement DFS 5.1 is a non‑contact Doppler ultrasonic flow switch designed for pump protection and flow/no‑flow alarming of difficult liquids. It is recommended for wastewater, cooling water, slurries, sludge, chemicals, viscous liquids and abrasives that would normally damage contacting flow switches. The ultrasonic sensor mounts on the outside of any metal or plastic pipe from 12.5 mm (0.5″) to 4.6 m (15′) ID, without cutting the pipe or interrupting the process.

Easy Installation and Operation

Installation takes only minutes and the switch is maintenance‑free. The control relay (5 A DPDT) can be set to turn ON/OFF at any velocity between 0.075 m/s and 3 m/s (0.25–10 ft/s). The user can insert two links for separate ON/OFF setpoints or one link for a high or low flow alarm. Adjustable time delay prevents nuisance alarms and relay chatter in turbulent flow.

Technical Specifications

• Sensor: Single‑head ultrasonic transducer, 316SS housing, 6 m (20 ft) shielded cable
• Electronics Enclosure: NEMA4X (IP66) polycarbonate with clear, shatterproof cover
• Power Supply: 100-240 VAC 50-60 Hz, 10 VA max; optional 12-24 VDC
• Operating Temperature (Electronics): -23°C to 60°C (-10°F to 140°F)
• Operating Temperature (Sensor): -40°C to 150°C (-40°F to 300°F)
• Repeatability: ±0.1% of full scale (3 mm/s)
• Pipe Size Compatibility: Any pipe ID from 12.5 mm to 4.6 m (0.5″ to 15′)

Applications

The DFS 5.1 is widely used in wastewater treatment, mining, chemical processing, food & beverage, pulp & paper and other industries where abrasive or viscous liquids make traditional in‑line flow switches impractical.