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 - Discontinued Portable ultrasonic Flow meter


Portable ultrasonic Flow meter | FDT-21

Portable ultrasonic Flow meter

  • Portable ultrasonic Flow meter with a 1% accuracy
  • Repeatability 0.2%
  • Positive, Negative and Net Totalizer
  • 4-Line LCD Display
  • Clamp On Transducers
  • RS232 Output
Doppler/Transit-Time Ultrasonic Flowmeters - View related products


Find how a Ultrasonic flow meter works on this link.

The FDT-21 series has been discontinued. We only have limited stock of some of the accessories.

Please see the FDT-25 series as a possible alternative or contact our Technical Sales department.

FDT-21 portable ultrasonic flow meter is designed to measure the fluid velocity of liquid in a full/closed pipe. It is a handheld measurement system which is both easy to install and use. The FDT-21 operates according to the difference in the transit time of flight measured, and determines the flow velocity by measuring the travel time of a pulse from one transducer to the next.

Flow in the same direction takes less time to travel to the second transducer than does flow in the opposite direction. Electroacoustic transducers receive and emit brief ultrasonic pulses through the liquid of the pipe. Transducers are vertically placed at both sides of the measured pipe. Sensors are placed on the pipe and fastened by means of a clamp. The display will quickly show the flow velocity. The FDT-21 can be used for metallic, plastic and rubber tubes.

±1% of reading >(0.2m/s) 0.6 ft/s
Repeatability: 0.2%
Linearity: 0.5%
Response Time: 0 to 999 seconds (user configured)
Velocity: (±0.01 to 30 m/s) ±0.03 to 105 ft/s bi-directional
Temperature Range:
    Standard: 0 to 70°C (32 to 158°F)
    With High Temp Transducers: 0 to 160°C (32 to 320°F)
Pipe Size: DN 19 to 100 mm (0.75 to 4") standard [up to DN 6000 mm (236") with optional transducers]
Transducer Frequency: 1 MHz
Rate Units (User Configured): Meter, feet, cubic meter, cubic feet, USA gallon, liter, oil barrel, USA liquid barrel, imperial liquid barrel, million USA gallons
Totalizer: 7-digit totals for positive, negative and net flow
Liquid Types: Most liquids including clean water, sea water, waste water, chemical liquids, oil, crude oil, alcohol, beer, and more
Suspension Concentration: .20,000 ppm (may contain very small amounts of air bubbles)
Pipe Material: All metals, most plastics and fiberglass
Security: Programmable lock-out code
Display: 4 x 16 english letters
Communications: RS232C (baud rate from 75 to 115,200 bps)
Transducer Cable Length: 5 m
Power: 3 "AAA" Ni-H built-in batteries (included) with 90 to 230 Vac charger, fully charged lasts over 12 hrs.
Data Logger: Built-in, stores over 2000 lines of data
Totalizer/Calibration: 7-digit press-to-go for calibration
Housing: ABS plastic with aluminium alloy protective carrying case
Case: NEMA-4 (IP65)
Dimensions: 100 H x 66 W x 20 mm D
Weight: 514
Place Order(Specify Model Number)
Part Number/ Desc.
Quick Ship
Availability: 1 week
Large (300 mm to 6 m dia) pipe high temp transducer.
Quick Ship
Availability: In Stock
Medium (50 to 700 mm dia) pipe high temp transducer.
Quick Ship
Availability: 1 week
Replacement small (20 to 100 mm dia) pipe high temp transducer
Quick Ship
Availability: In Stock
Acoustic gel for standard transducers
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Availability: In Stock
Replacement Universal AC Adaptor
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Availability: 1 week
(Replacement) Transducer pipe clamp set for up to DN100 (4")
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Availability: 1 week
Transducer pipe clamp set for up to DN200 (8")
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Availability: 1 week
Transducer pipe clamp set for up to DN300 (12")
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Availability: 7 weeks
Transducer pipe clamp set for up to DN400 (16")
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Availability: 1 week
Transducer pipe clamp set for up to DN500 (20")
Quick Ship
Availability: 1 week
Transducer pipe clamp set for up to DN600 (24")
All amounts shown in EUR, GBP, or USD
Note: Comes complete with 3 "AAA" batteries, small pipe standard/high temperature (S2H)transducer, acoustic gel, tape measure, universal AC power adapter, RS-232 cable, transducer cable, rugged carrying case and operator’s manual.

Product Manuals:

Download FDT-21 - Ultrasonic Flow Meter
Download Medidor Ultrasonics de Fiujo
Download Manuel d’utilisateur - Compteur de débit ultrasonique