Doppler Flow Switch DFS 5.1
- 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 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.
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.
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.
- Sewage
- Viscous liquids
- Acids Slurries
- Solvents
- Treated wastewater
- Sludge
- Pulp stock
- Food products
- Oils
- Paint
- Chemicals
- Aerated Water
- Cooling Water
DOPPLER FLOW SWITCH SPECIFICATIONS
SCOPE: This specification covers a non-intrusive, ultrasonic Doppler-type flow switch as manufactured by Greyline Instruments Inc., Massena, New York / Long Sault, Ontario. The instrument shall provide for flow control at adjustable flow velocities.
A. PERFORMANCE SPECIFICATIONS
- The flow switch shall operate with a clamp-on ultrasonic sensor mounted externally on any contiguous pipe material that conducts sound including: carbon steel, stainless steel, ductile iron, copper, FRP, PVC, ABS, or cement lined pipe from 1/2" to 180" (12.5 mm to 4.5 m) diameter.
- Shall operate on liquids with entrained particles or gases of 100 microns or larger and minimum concentrations of 75 ppm.
- The control ON and OFF set-points shall be independently adjustable for flow rates between 0.25 ft/sec (0.076 m/sec) and 10 ft/sec (3 m/sec).
B. TRANSDUCER (SENSING ELEMENT)
- The flow sensor shall be single-head, ultrasonic in a stainless steel housing. It shall be installed on the outside of a pipe without interrupting flow. The sensor shall be capable of continuous operation at temperatures from -40°F to 300°F (-40°C to 150°C), and to withstand accidental submersion pressures to 10 psi.
- Manufacturer's recommended coupling compound and stainless steel pipe clamp shall be included.
- Shall connect to separate electronics housing with 20 ft (6m) shielded coaxial cable pair with waterproof, potted bond to the Sensor head.
- Shall be capable of extending sensor cable up to 500 ft (152m) without adjustment and with no reduction in performance or signal strength.
C. ELECTRONICS/CONTROLLER
- Shall be housed in a wall-mount watertight, dust tight NEMA4X (IP 66) polycarbonate enclosure with a gasketed shatter proof window.
- Have a power input of 100–240VAC 50-60Hz (±10%), 2.0 W Max.
- Shall include one 5 ampere DPDT control relay.
- Shall operate in Hi or Lo alarm mode, or with separate ON/OFF set points individually adjustable between 0.25 and 10 ft/sec (0.076 to 3 m/sec).
- The controller shall include an indicator LED to display relay status and a LED bargraph to display flow rate.
- The controller shall include relay time delay adjustment from 0 to 80 seconds.
- The flow switch electronics/controller shall operate at temperatures from -10° to 140°F (-23° to 60°C).
- Shall be designed for maximum RFI rejection.
D. OPTIONAL FEATURES FOR INSERTION IN SPECIFICATION AS REQUIRED
- Have a power input of 12-24VDC (±10%), 3.0 W Max.
- Have 50 ft (15 m) continuous length shielded coaxial pair sensor cable.
- Have 100 ft (30 m) continuous length shielded coaxial pair sensor cable.
- Have a Cable Junction Box and up to 500 ft (152 m) total length cable that shall be shielded coaxial pair and installed in conduit for mechanical protection.
Doppler flow meters measure flow from outside a pipe with a clamp-on sensor. Greyline Doppler meters continuously transmit high frequency sound (640 kHz) that travels through the pipe wall and into the flowing liquid. Sound is reflected back to the sensor from solids or bubbles in the fluid. If the fluid is in motion, the echoes return at an altered frequency proportionate to flow velocity. Doppler flow meters continuously measure this frequency shift to calculate flow.
Measure Flow of dirty or aerated Liquids from Outside a Pipe
The Doppler effect was first documented in 1842 by Christian Doppler, an Austrian physicist. We hear everyday examples of Doppler: the sound of a train whistle changing pitch as it passes by, or the exhaust noise from a race car as it speeds past our location.
The Doppler technique only works on liquids which contain solids or gas bubbles to reflect its signal. These are "difficult" liquids that may damage regular flow meters: slurries, sludge, wastewater, abrasives, viscous and corrosive chemicals. Because the sensor mounts on the outside of the pipe, there is no pressure drop and no obstruction to flow.
For best performance Doppler sensors should be mounted away from turbulence creating devices like pipe elbows and tees, and away from velocity increasing devices like controlling valves and pumps. Typical accuracy is ±2% of full scale.
Doppler instruments include a clamp-on ultrasonic sensor, connecting cable and an electronics enclosure which can be mounted at a convenient location nearby (within 500 ft / 152 m). Sensors can be rated intrinsically safe for mounting in hazardous-rated locations.