DFS 5.1 Doppler Flow Switch

Greyline, DFS 5.1, Doppler Flow Switch, ultrasonic flow switch, Doppler flow control, outside a pipe, pump controls, pump protection, flow alarms, non-contacting, non-invasive, non-intrusive, ultrasonics, strap-on sensors, clamp-on, acoustics, entrained air, slurries, sludge, abrasives, no obstruction, no pressure drop, municipal, industrial, sewage, wastewater, DFS-11

  • Flow Control from the Outside of Metal or Plastic Pipes
  • 5 amp DPDT Control Relay
  • Adjustable ON/OFF Set-Points
  • Hi or Lo Flow Alarm Mode
  • Adjustable Time Delay
  • Relay Status LED
  • Flow Rate LED bargraph


Flow Switch With Non-Contacting Sensor

Control Flow from outside a pipe. Recommended for "difficult liquids" including wastewater, cooling water, slurries, sludge, chemicals, viscous liquids and abrasives. The Greyline DFS 5.1 is ideal for pump protection or to activate flow/no-flow alarms.

Easy to Calibrate

The DFS 5.1 control relay can be set to turn ON and OFF at any flow rate between 0.25 and 10 ft/sec (0.075 to 3 m/sec). Insert two links for separate ON/OFF set points or just one link for a Hi or Lo flow alarm. Set the relay actuation time delay from 0 to 80 seconds. DFS 5.1 Easy Calibration

A bright LED indicator shows the relay state and a LED bargraph shows the flow rate. Electronics are housed in a watertight polycarbonate wall-mount enclosure.

Clamp-on Ultrasonic Sensor for DFS 5.1 Doppler Flow Switch

The clamp-on ultrasonic sensor mounts on the outside of metal or platic pipes without cutting the pipe or shutting down flow. It works on any pipe diameter 1/2" (12.5 mm) or larger and installs in minutes. There are no moving parts and no maintenance is required. The shielded sensor cable length is 20 ft. (6 m) and can be extended up to 500 ft. (152 m) with an optional Junction Box.

DFS 5.1 Brochure
DFS 5.1 User's Guide
Dow Corning Coupling Compound MSDS

DFS 5.1 Engineering Specifications

How Doppler Works


Doppler Flowmeter for Display and Control...

Combine flow control with a complete flow metering solution through the Greyline DFM 5.1 Doppler Flow Meter. It displays flow rate, totalizes and includes 2 fully programmable control relays.


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