Dynasonics DUFX1 Doppler

Electronics Specifications

Flow Range:  0.30 to 30 FPS (0.10 to 9 MPS)
Display:  Single line, four-digit LCD readout of velocity  0.9”  (18 mm) high digits, signal strength, measuring units and low battery indication  •  Accuracy:  ±2% f.s.
Temperature:  -28 to 140°F (-20 to 60°C)
Enclosure Rating:  NEMA 12X ABS plastic
Dimensions:  7.76 H x 4 W x 1.5”  •  Weight:  1.5 pounds
Agency Approval:  FM and CE mark (pending)
Supply Voltage:  Battery powered, non-rechargeable alkaline, four ‘AA’ batteries provide over 30 hours of continuous operation

Transducer Specifications

Transducer Material:  Plated body, ULTEM 1000 sensor material
Cable:  6.6 feet (2 meters) cable and connector
Temperature:  -40 to 180°F (-40 to 87°C)
Mounting Method:  Clamp-on style with DOW 111 coupling compound
Humidity:  0 to 95% non-condensing

Successful application of Doppler ultrasonic flow meters relies on three physical constraints:

1. The liquid flowing within the pipe must contain 100 ppm of useful sonic suspended reflectors – dissolved solids do not generate reflections and are not relevant.
   •  The speed of sound of the reflector must vary by greater than 10% from that of the liquid carrier.
   •  Particles must be large enough to cause longitudinal reflection. Particles greater than 35 micron size meet this criteria.
   •  In typical applications, there is often a distribution of particle sizes. If the volume of particles greater than 100 microns is 25% of the overall particle volume, then the reflectors are adequate for a Doppler ultrasonic flow meter.
   •  The reflecting material must travel at the same velocity as the fluid for good accuracy. Upward flowing pipes running at low velocities may not carry heavier reflectors at the same velocity as the carrying liquid – leading to inaccurate flow measurements.
2. A significant portion of the ultrasound energy generated by the transducer must reach the sonic reflectors.  In the case of a clamp-on transducer, the ultrasonic transducer must be acoustically coupled to the outside of a pipe (using grease or RTV couplant) and the pipe must permit ultrasound to pass without significant attenuation.  Most pipes constructed of solid, homogenous materials meet this qualification.  Pipes that cause application difficulty include concrete pressure pipes, wooden stave pipes, Teflon-lined pipes and fiberglass reinforced pipes.  Pipes that do not readily pass ultrasound are candidates for the DP7 insertion probe transducer.
3. The pipe must be completely filled with liquid when measurements are made.  The DFX microprocessor assumes that the pipe is completely full when it calculates flow rate.  Use on partially-filled pipes may result in inaccurate readings.