- Model PDFM 5.1 - Portable Doppler Flow Meter



It's ideal for flow troubleshooting, balancing and checking performance of permanent flow meters. The new PDFM 5.1 is fast and easy to operate – you can mount the sensor on the outside of a pipe in less than a minute. Use the built-in keypad and calibration menu to set up the flowmeter for your application. The PDFM 5 works on any liquid containing bubbles or solids and is recommended for 'difficult liquids' like wastewater, slurries, sludge, chemicals, viscous liquids and abrasives. Measures flow through most metal and plastic pipes including PVC, ductile iron, carbon steel and stainless steel.


The Greyline PDFM 5.0 is AC/DC powered with built-in NiMH batteries and external charger. With its 4-20mA output you can use the PDFM 5.0 as a spare transmitter in critical applications. For flow studies and troubleshooting use the built-in 300,000 point Data Logger. Retrieve data logs with 'Greyline Logger' software – included free with each PDFM 5.0. Connect the USB output directly to your PC or Laptop to download data logger files.

The PDFM 5.0 includes a non-intrusive Doppler ultrasonic sensor for pipes from 1/2' to 180' (12.5 mm to 4.5 m) diameter, a stainless steel sensor mounting bracket and clamps, coupling compound and AC charger with a rugged IP67 carry case. It operates up to 18 hours from internal batteries and recharges overnight.

Start-up of a PDFM 5.0 Portable Doppler Flow Meter
It's easy to mount the clamp-on ultrasonic sensor and start-up the PDFM 5.0 to measure flow in pipes 1/2' diameter or larger.

  • Clamp-on Ultrasonic Transducer
  • Handheld Meter with large backlit LCD Display and Totalizer
  • Internal Battery and/or AC Powered
  • Built-in 5-Key Calibrator
  • 300,000 point Data Logger
  • USB Output and Windows software
  • 4-20mA Output
  • Rugged, watertight Carry Case

  • Troubleshoot and Balance Flow
  • Check Performance of Pumps or other Flow Meters

Quick, Easy Flow Measurements from Outside a Pipe
Each Greyline PDFM 5.0 comes complete with rugged watertight strap-on sensor and stainless steel mounting kit. Use the simple 5-key menu system to select units of measurement and to calibrate to any pipe diameter ½” (12.5 mm) or larger.

Simple start-up and Calibration
Sensor mounting and a full calibration can be done in just a few minutes. It is fast and easy! Put coupling compound gel (included) on the sensor face and mount the sensor on the outside of a pipe with the stainless steel mounting bracket (supplied). Use the five-key calibration system to enter pipe diameter and to select your choice of engineering units (gallons, litres etc.) The PDFM 5.0 will immediately begin to display, transmit and totalize.


Select your choice of display units: the PDFM 5.0 will display and totalize flow volume in gallons, liters, cubic feet or cubic meters. If you change from one measurement system to another, the PDFM 5.0 will automatically and instantly calculate and convert the flow display and totalizer. Calibrate to the pipe size using the keypad to enter inside diameter.

Built-in 300,000 point Datalogger and PC Software
Set up the PDFM 5.0's data logger to store time and datestamped flow values from 10 second to 5 minute intervals. Or use the convenient 'Flow Report' format where total, minimum, maximum and average flow rates are stored in your choice of hourly or daily summaries. Transfer flow logs to your PC or laptop through the PDFM 5.0's USB output. Greyline Logger software (included) displays data in both graph and table formats and exports to graphic or text file formats for use in other programs.


Sleep mode extends battery life for long-term data logging at locations where AC power input is not available. Between logging intervals the flowmeter drops into a stand-by mode until a flow reading is requested by the data logger. Flow rates are sampled continuously for 10 seconds and then the PDFM 5.0 returns to sleep until the next logger point is required. With 5 minute sample intervals the PDFM can data log for about 18 days on battery power.

New Signal Processing for reliable Accuracy
The PDFM 5.0 Doppler flow algorithm filters out background noise and interference. The digital signal processor discriminates against weak and distorted signals. When the processor cannot measure accurately the meter will display zero flow and indicate low signal confidence.

Battery Powered for a Full Day’s Work
With its built-in NiMH rechargeable battery, you can operate the PDFM 5.0 up to 18 hours continuously. Display brightness is adjustable to conserve power. Plug into an AC outlet (100-240VAC 50/60Hz) to activate the 4-20mA output and to recharge fully in 6 to 8 hours. You can continue to use the PDFM 5.0 while charging.

General Specifications: Greyline PDFM 5.1 Portable Doppler Flow Meter

  • Flow Rate Range: ± 0.1 to 40 ft/sec (± 0.03 to 12.2 m/sec) in most applications
  • Pipe Size: Ultrasonic Sensor mounts on any pipe from ½' to 180' ID (12.5 mm to 4.5 m)
  • Display: White, backlit matrix - displays flow rate, totalizer, operating mode and calibration menu
  • Power Input: Built-in NiMH battery for up to 18 hours continuous operationm, External charger with 100-240VAC 50/60Hz input
  • Outputs: 4-20mA (500 ohm) when AC powered, USB for Data Log transfer by direct PC connection
  • Data Logger: Programmable 300,000 data point capacity, time and date stamped or formatted flow reports including total, average, minimum, maximum and times of occurrence
  • PC Software: ‘Greyline Logger’ for Windows Vista or higher. Retrieves, displays and saves data log files
  • Electronics Operating Temperature: -10° to 140°F (-23° to 60°C)
  • Electronics Enclosure: Portable, ABS enclosure
  • Carry Case: Rated IP67 with protective molded foam insert
  • Accuracy: ±2% of reading or 0.1 ft/sec (0.03 m/sec). Requires solids or bubbles minimum size of 100 microns, minimum concentration 75 ppm. Repeatability: ±0.1%, Linearity ±0.5%
  • Calibration: Built-in 5-key programming with user-friendly calibration menu. Password protected.
  • Language Selection: English, French, Spanish
  • Sensitivity: Adjustable cut-off, Damping: adjustable
  • Approvals: Charger is CE and UL approved. The PDFM 5.1 is not certified for use in hazardous rated locations

Sensor Specifications

  • Standard Model PSE4: Clamp-on, single-head ultrasonic for pipes from ½' to 180' ID (12.5 mm to 4.5 m) with 12 ft (3.4 m) shielded dual-coaxial cable
  • Sensor Mounting Kit: Stainless steel pipe clamp and 5.3 oz. (150 g) silicone coupling compound
  • Operating Temperature: -40° to 300°F (-40° to 150°C)


  • Sensor Cable: 50 ft (15 m) sensor cable extension, shielded, with connectors
  • Sensor Mounting: Extra silicone coupling compound. Additional stainless steel pipe clamps

  • Sewage Flow Monitoring
  • Treated wastewater Flow Monitoring
  • Aerated water Flow Monitoring
  • Sludge Flow Monitoring
  • Slurries Flow Monitoring
  • Chemicals and solvents Flow Monitoring
  • Viscous liquids Flow Monitoring
  • Abrasives Flow Monitoring
  • Food products Flow Monitoring
  • Pulp stock Flow Monitoring
  • Acids and caustics


The PDFM 5.0 works best with difficult liquids in applications that would damage regular flow meters. Because the sensor is mounted on the outside of the pipe, there is no contact with the moving fluid.

The ultrasonic sensor straps onto the outside of pipes ½' (12.5 mm) ID or larger and measures flow in common pipe materials: PVC, carbon steel, stainless steel, cast iron, fiberglass, and lined pipes...any pipe that conducts ultrasound. Doppler signals cannot be transmitted through pipe walls which contain air pockets (materials like concrete and wood), or loose insertion liners (with an air gap between the liner and pipe wall). Because the sensor is so easy to install you can test any application and pipe material in a few minutes.


The PDFM 5.0 ultrasonic sensor injects high frequency sound through the pipe wall and into the flowing liquid. Gas bubbles or solids suspended in the liquid reflect the ultrasonic signal back to the sensor. When this sound is reflected from moving bubbles or particles it is returned to the sensor at an altered frequency. This frequency shift is called the Doppler effect. The PDFM 5.0 continuously measures the change from it's transmitted frequency to the received frequency to accurately calculate flow.

Scope: This specification covers a portable, ultrasonic Doppler-type flow meter as manufactured by Greyline Instruments, Massena, New York / Long Sault, Ontario. This instrument shall provide for non-intrusive flow measurement, indication, totalizing, transmitting and data logging of the flow rate in a full pipe.

Each portable Doppler flow meter shall have the following design features and engineering specifications:

Performance Specifications

  1. Measure forward and reverse flow ± 0.1 to 40 ft/sec (± 0.03 to 12.2 m/sec).
  2. Have an accuracy of ±2% of full scale on most wastewater applications. Have linearity of ±0.5% and repeatability of ±0.25%.
  3. Operate on liquids with entrained particles or gases of 100 microns or larger and minimum concentrations of 75 ppm.
  4. Operate from the outside of common pipe materials including: carbon steel, stainless steel, ductile iron, copper, PVC, FRP, ABS and other selected engineering materials.
  5. Operate on AC/DC power.


  1. Have a single-head, clamp-on transducer with twin piezo-electric ceramic transmit and receive crystals encapsulated in epoxy resin and a stainless steel housing.
  2. The transducer shall be solid state and transformer isolated, and operate at 640KHz.
  3. The transducer shall be waterproof and operate at temperatures from -40°F to 300°F (-40°C to 150°C), and withstand accidental submersion to 10 psi.
  4. The transducer shall be designed to install on pipes with inside diameter ranging from 1/2' to 180' (12.5 mm to 4.5 m).
  5. Have a 12 ft (3.6 m) long flexible, shielded coaxial pair cable extending from the transducer to the electronics.
  6. Shall include Manufacturer's recommended sensor coupling compound and adjustable stainless steel sensor mounting clamp.


  1. Have a portable ABS electronics enclosure with a padded, watertight IP67 carrying case. Total weight shall be less than 14 lbs (6.5 kg).
  2. Electronics shall be designed for continuous operation at temperatures from -10° to 140°F (-23° to 60°C).
  3. Have a built-in 5-key calibration keypad with operator selection of parameters through visual prompts from a menu calibration system. Systems requiring calibration by Parameter codes or external calibrators shall not be accepted.
  4. Have user-selectable menu languages including English, French and Spanish.
  5. Have a white, backlit matrix display indicating flow in user-selected engineering units, totalized flow, units of calibration, and signal strength.
  6. Have display backlight brightness adjustment for reduced power consumption.
  7. Have flow proportional 4-20mA output rated to maximum resistive load of 500 ohms.
  8. Have a built-in 300,000 point data logger, USB output and connecting cables. Data logger shall support time and date-stamped logging and generate formatted flow reports including total, average, minimum, maximum and times of occurrence.
  9. Include Windows software for data log retrieval, graphing and export.
  10. Have automatic signal strength and signal confidence monitoring.
  11. Have keypad adjustable signal cutoff to reduce interference.
  12. Shall include an external charger with 100-240VAC 50/60Hz input.
  13. Shall include an internal NiMH rechargeable battery with minimum capacity for 18 hours continuous battery operation.
  14. Have a battery status indicator with automatic low battery shut off and battery overcharge protection.
  15. Have user-selectable 'sleep mode' synchronized to data logger sample rate for reduced battery power consumption.

Optional Features For Insertion In Specification As Required:

  1. Include additional 150 g. manufacturer's recommended ultrasonic sensor coupling compound.
  2. Include 50 ft (15 m) length Sensor Cable extension complete with connecting plugs.

The instrument shall be a Model PDFM 5.0 Portable Doppler Flow Meter as manufactured by Greyline Instruments Inc., and warranted against defects in materials and workmanship for one year.

Customer reviews

No reviews were found for Greyline - Model PDFM 5.1 - Portable Doppler Flow Meter. Be the first to review!