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Case Study





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Ultrasonic Doppler flow meters operate by transmitting and receiving ultrasonic sound signals in liquids. An instrument, such as the DMDF1, incorporates dual transducers that are clamped on opposite sides of a liquid filled pipe. Each transducer contains a piezoelectric crystal.

Referring to the above illustration, the ?1 transducer transmits an ultrasonic signal through the pipe wall into the liquid. A portion of this signal is reflected by suspended solids, entrained gases or flow turbulence moving with the fluid, back toward the second transducer, ?2, Electronic circuitry compares the transmitted frequency with the received frequency.

The difference, or frequency shift, is proportional to fluid velocity, in accordance with principles developed by Christian Johann Doppler. If the liquid is not moving (a zero flow condition) the transmitted and received frequencies are identical.

The DMDF3 features advanced signal processing and an exclusive auto-adapting digital filter to produce accurate and stable indications of flow rate and totalized flows. A full function keypad allows field configuration of pipe size, engineering units, the 4-20mA output and all operating parameters.


  • The system can be field configured to pipe sizes ranging from 1 to 120 inches [25 to 3050 mm].
  • Non-fouling transducer is immune to build-up of grease, paraffin and other coating materials.
  • Solid-state measurement never requires re-calibration and is virtually maintenance-free.
  • Operates with relatively clean liquids as well as liquids with concentrations of suspended solids or aeration.
  • Does not require long straight runs of pipe.
  • Rugged NEMA 4X design permits extended outdoor and rough service use.
  • Industry standard outputs allow direct interface to loggers and controls systems.



Flow Rate Range : 0.25 to 40 ft/sec (0.08 to 12.2m/sec) in most applications
Pipe Size : Any pipe ID from ½" to 180º(12.7mm to 4.5m)
Accuracy : ±2% of full scale. Requires solids or bubbles minimum size of 100microns, minimum concentration 75ppm.
Repeatability : ±1% linearity, ±0.5% of full scale
Displays : flow rate - large 4 digit LCD in programmable engineering units. Totalizer/Menu/status/Signal Strength -16-digit LCD, alphanumeric.
Calibration : built-in 3-key calibrator.
No-drift transmitter : Quartz crystal frequency reference
Power Input : 100-130VAC 50-60Hz(See Options), 5 watts maximum / built-in Battery with Internal Charger
Output : isolated 4-20mA(1000 ohm load max)
Control Relays : Qty 3 rated 5 amp SPDT Programmable flow alarm and/or proportional pulse
Back Flow Rejection : Forces display and outputs to zero with contact closure from remote relay
Enclosure : water tight, dust tight NEMA4X(ip 66) fibreglass with a Clear shatter-proof face
Electronics Operating Temperature : -10º to 140º F(-23º to 60º C)
Sensitivity : adjustable
Damping : adjustable
Electrical Surge Protection : Sensor, 4 - 20mA output and AC power input
Shipping Weight :

12 lbs(5kg)


Model SE3 single-head ultrasonic with 20 ft(6m) sheilded cable and stainless steel mounting kit for pipes ½* (12.7 mm) ID or larger. Designed to withstand accidental submersion to 10 psi(non-functional while submerged).

Sensor Operating Temperature : -40° to 200°F(-40° to 93°C)


Sensor A: Intrinsic safety barriers for sensor mounting in hazardous Locations. SE3H high temperature model rated upto 302ºF(150ºC)
Sensor B: Use the Insertion Sensor and Doppler Flow Meter when the pipe material prevents transmission of Ultrasonic Signal throught the pipe wall. 

Pipe Diameter: 2" to 48"
Sensor C: PDSE-5 Dual Head Doppler Sensor
Sensor Cable : 50 ft(15m) continuous shielded coaxial pair, or splice upto 500 ft (152m) with junction box. Self tunes to extended cable
Enclosure Heater : for outdoor installation, 16 watt thermostatically controlled to -40º F(-40ºC)
Data Logger : Built-in 50,000 point logger with RS232 output and Windows Software
Power Input : 200-260VAC 50-60Hz, 24VDC or 12VDC (Battery Power)


  • Wastewater sludges
  • Ground water
  • Flow surveying
  • Remote field site flow tests
  • Used as a flow prover to other flow technologies
  • Mining recirculate
  • Pump output verifications
  • Sewage lifting station
  • monitoring



The PORTAFLOW is a Transit Time Ultrasonic flow meter. It measures flow by injecting sound from a transmitting sensor, through the pipe wall into the following liquid and then to a receiving sensor. The elapsed time between transmitted and received signals is very precisely calculated by the flow meter.

Then the sensors trade functions. The original receiving sensor function now becomes the transmitting sensor and the ultrasonic signal is transmitted in the opposite direction. Again the elapsed time between transmitted and received signals is calculated.

The transit time in the direction of flow is faster than the transit time against the flow. By comparing these time differences the PORTSFLOW is able to accurately calculate the flow rate. Because the ultrasonic signal is forcedto cross the pipe, an average of the flow profile is calculated. So compensation for laminar or turbulent flow is automatic. 

The Portaflow Transit Time flow meter is designed for clean, non-aerated liquids(<2% of Volume). High concentrations of solids or gas bubbles will attenuate the ultrasonic signal or sound will not be able to cross the pipe. A Greyline Doppler-type flow meter is recommended for applications with solids or bubbles (eg. Waste water or slurries).


  • Cost effective and versatile
  • High accuracy, better than 1.0% read
  • Noninvasive, no moving parts, no pressure drop, no maintenance
  • Easy and economical installation, no pipe cutting
  • Wide measurement range, 0.03~40ft/s (0.01~12m/s)
  • Wide pipe size range, 3/ 4~180 inches (DN 20~4570mm)
  • Suitable for all commonly used pipe materials
  • Signal quality tracking and self-adjusting capabilities
  • automatically match transducer to pipe materials
  • Velocity, volumetric and totalized flow display
  • Bi-directional. Totalizer for net, positive and negative flow display
  • Easy to use and set up. Self-explanatory menu-driving programming
  • Rich input and output functionalities
  • Ideal for both clean and opaque liquid flow measurements.
  • In fact, most any liquid containing less than 5% total suspended solids (TSS) or aeration.


Fluid/Application: Recommended for clean liquids with less than 2% solids or gas bubbles
Flow Rate Range: 0.65 to 40 ft/sec (0.2 to 12 m/sec)
Pipe Size: Ultrasonic sensors mount on any pipe from 2" to 40" ID (50 mm to 1000 mm)
Pipe Materials: Any sonic conducting material including carbon steel, stainless steel, PVC,
PVDF, fiberglass, galvanized steel, mild steel, glass, copper, brass and pipes
with bonded liners including epoxy, rubber and Teflon
Display: Backlit LCD matrix. Displays flow rates in m , liters, or gallons (per minute or
hour), and flow velocity in feet per second or meters per second. Displays
positive and negative flow and data log files in graphic or text modes.
Totalizer: 12 digits - displays separate forward and reverse flow totals
Power Inputs: Built-in rechargeable NiMH battery powers the Portaflow for 6-10 hours
continuously. The external charger operates from 100-240 VAC power input
Outputs: 4-20mA (750 ohm), Serial RS232-C with adjustable baud rates for data transfer
to a PC
Data Logger: programmable, 50,000 data point capacity, time and date stamped values
Electronics Operating Temperature: 32° to 122°F (0° to 50°C). Storage Temperature: 14° to 140°F (-10° to 60°C)
Electronics Enclosure: Portable, ABS enclosure with lockable carrying case
Accuracy: ±2% of reading, Repeatability: ±0.5%
Calibration: Built-in 16-key programming with user-friendly calibration menu. Stores
calibration parameters for up to 20 different sites.
Approvals: CE (conforms to EN50081-1 emission and EN50082-1 immunity standards).
Charger is CE, CSA and UL approved. The Portaflow SE is certified for use
in hazardous rated locations.


Transducer Model PTSE1: Clamp-on 1 MHz ultrasonic for pipes from 2" to 40" ID (50 mm to 1000 mm).
Transducer Mounting Kit: Includes stainless steel guide rail, mounting chains and coupling compound
Operating Temperature: -4° to 257°F (-20° to 125°C)


  • Portable water
  • River water
  • Cooling water
  • Demineralized water
  • Water/glycol solutions
  • Hydraulic oil
  • Diesel and fuel oils
  • Chemical

The PORTAFLOW SE is ideal to measure flow rate of clean, non-aerated fluids in full pipes. Works best on fluids that have less than 2% particulate or gas bubbles.


The DMTFB flow meters are ideal for process-control or flow measurement at fixed locations. Their non-invasive nature makes them indispensable in applications such as chemical liquid processing, hygienic process monitoring, high-pressure flow measurement, etc. Benefited from our advanced digital signal processing technology, the flow meter works reliably in both clean and opaque liquid flow. Examples of applicable liquids are:

  • Water, including hot water, chilled water, city water, sea water, etc.
  • Secondary sewage, waste treatment, etc.
  • Oil, including lubricating oil, diesel oil, fuel oil, etc.
  • Chemicals, including alcohol, acids, etc.
  • Solvents
  • Beverage, food and pharmaceutical processors where non-contact is a must.
  • HVAC, energy measurement system, etc.