Part#: 73126
Weight: 5.0 lbs

Greyline DFS 5.1 Doppler Flow Switch 100-240 VAC, 20'L Cable, DFS 5.1-A1A

  • Controls flow from outside a pipe
  • Protects pumps from running during no-flow conditions
  • Easy-to-read LED flow bar graph
Price: $945.00
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Need Help? Call 800-548-1234

The Greyline DFS 5.1 Doppler flow switch controls the flow of liquids containing bubbles or solids in closed pipes. Its noncontacting sensor allows it to excel where contacting sensors fail—great for wastewater, cooling water, slurries, sludge, chemicals, viscous liquids and abrasives. Flexible and adaptable, it's ideal for triggering high- or low-flow alarms, controlling pumps, and protecting pumps during no-flow conditions.

Installation, setup and operation are fast and easy—no manual or complicated programming instructions needed. Strap the sensor to a pipe in minutes without shutting down flow or cutting pipe. Set up relay outputs using basic pin jumpers for ON and OFF at any flow rate between 0.25 and 10 ft/sec (high or low flow). For separate ON/OFF setpoints with a deadband, insert two jumpers.

Relay actuation time delay is adjustable from 0 to 80 seconds using a knob, which is especially useful to eliminate relay chatter (short-cycling pumps). An LED bar graph indicates real-time flow velocity; a single red LED indicates when the relay is energized. All electronics feature integral surge protection.

Sensor cable is 20 feet long, but is field-extendable up to 500 feet (requires shielded cable and junction box; each sold separately).

Includes: Doppler sensor, sensor mounting bracket, strap with clamp (for pipe up to 16" OD) and acoustic coupling compound.

How it works: The ultrasonic sensor of the DFS 5.1 injects high-frequency sound through the pipe wall and into the flowing liquid. Gas bubbles or solids suspended in the liquid reflect this sound back to the sensor. When the transmitted sound reflects from moving bubbles or particles, it returns to the sensor at an altered frequency. This frequency shift is called the Doppler effect. The DFS 5.1 continuously measures the change between the frequency it transmits and the one it receives to accurately calculate flow.

Note: For best performance, consider several installation details. For both vertical and horizontal pipe runs, the pipe must be full and the liquid must contain a concentration of bubbles or solids of at least 100 microns and 775 ppm. Sensor mounting location is also critical. Choose a location away from inline flow disturbances whenever possible: six diameters upstream and 10 diameters downstream is optimal for most disturbances.

Tech Specs
  • Power: 100-240 VAC 50-60 Hz
  • Relay output: one 5A, DPDT (adjustable time delay up to 80 seconds)
  • Display: flow rate 16-LED bar graph, relay status LED
  • Pipe size: 1/2" to 180" ID
  • Velocity range: 0.25 to 10 ft/sec
  • Accuracy: ±2%
  • Operating temp (electronics): -10 to 140°F (-23 to 60°C)
  • Operating temp (sensor): -40 to 300°F (-40 to 150°C)
  • Enclosure: NEMA 4X (IP67); polycarbonate w/ clear, shatterproof cover
  • Enclosure dimensions: 4.72"H x 3.54"W x 2.42"D