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Low Flow Indicating Paddlewheel Flow Meter

Micro-flow meter


Item# FTB321D

 This item is available for quick shipping
Volume discounts available
Volume Discount Schedule
Quantity Price each
1-4 $362.85
5-9 $344.71
10-24 $337.45
25-49 $322.94
50-99 $315.68
100+ $308.42

In stock

Lead Time ( If not in Stock): 3 weeks

Micro-flow meter FTB321D FTB321D
  • NEMA 4X (IP56) Enclosure
  • 6-Digit LCD
  • Displays both Rate and Total
  • Non-Volatile Programming and Total
  • For Clean Liquids

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Flow Range
Max Process Temperature
Max Operating Pressure
Wetted Materials
Output Signal
Supply Power
Process Connection Type
Process Connection Size

Product Specs

The FTB300 Series of digital paddle wheels are an economical choice for low flow rate applications. They use Infra-red light beam technology. Available connections include 1/8 FNPT, 1/4 FNPT and 3/8" OD tube fittings. Six available flow ranges as low as 30ml/min to 7000 ml/min. No display models have a 5 Vdc current sinking pulse output. Units with displays have a 6-digit LCD, with up to 4 decimal positions that display both flow rate and total. All units include an open collector alarm output.

User selectable scale factors include: flow units, gallons, liters, ounces, and milliliters. Time units include: minutes, hours, days. Users can also program custom units. Programming values and total are stored in the non-volitile memory. The total reset function can also be disabled. Standard units have a clear PVC viewing lens, PVDF chemical resistant lens are available as an option. The enclosure is a weather resistant Valox PBT and rated NEMA 4X (IP56).

Max Working Pressure:
    PVC Lens: 9 bar (130 psig) at 21°C (70°F)
    PVDF Lens ("-PVDF" Option): 150 psig (10 bar) @ 21°C (70°F)
Max Fluid Temperature:
    PVC Lens, FNPT Connectors: 54°C (130°F) at 0 PSI
    PVDF Lens ("-PVDF" Option), Tubing Connectors: 93°C (200°F) at 0 PSI
Full Scale Accuracy: ±6%
Input Power Requirement: 9 to 28 Vdc
Sensor Type: Infrared light beam
Alarm Output: Open collector 30 Vdc max
Enclosure: NEMA 4X (IP56)
Approximate Shipping Wt: 0.45 kg (1 lb) Materials of Construction
Body, Paddle, Axle Material: PVDF Connector Material
FNPT Connections: PVC
Tubing Connectors: PVDF Viewing Lens Material Option
    Clear See Through: PVC
    Opaque Chemical Resistant: PVDF (optional)
O-Ring Seals: FKM (EPDM optional)
Compression Seal to Pump: PVC Sensor Only
    Models: 5 Vdc digital square wave (2-wire)
    Output: 3-wire shielded cable, 1.8 m (6')

Model with Display Model without Display Range
1/8 FNPT 1/4 FNPT 3/8" OD Tube 1/8 FNPT 1/4 FNPT 3/8" OD Tube lpm gph
FTB311D FTB321D FTB331D FTB311 FTB321 FTB331 0.03 to 0.3 0.48 to 4.7
FTB312D FTB322D FTB332D FTB312 FTB322 FTB332 0.1 to 1 1.6 to 15.8
FTB313D FTB323D FTB333D FTB313 FTB323 FTB333 0.2 to 2 3.2 to 31.7
FTB314D FTB324D FTB334D FTB314 FTB324 FTB334 0.3 to 3 4.8 to 48
FTB315D FTB325D FTB335D FTB315 FTB325 FTB335 0.5 to 5 7.9 to 79
FTB316D FTB326D FTB336D FTB316 FTB326 FTB336 0.7 to 7 11.1 to 111

Rated 5 out of 5 by from Great little flow meter We purchased this flow meter for a test project and we really loved the ease of use and accuracy. Would definitely recommend this product to others.
Date published: 2015-11-24
Rated 5 out of 5 by from Right Tool for the Job. Bought this, received fast, fairly priced, and the perfect tool for my needs.
Date published: 2016-04-29
Rated 4 out of 5 by from Great product Good and precise flow meter, in addition, should have a hard reset switch, in case of the error
Date published: 2016-10-10
Rated 1 out of 5 by from Fittings don't fit The fittings that came with the flow meter did not actually fit. And they only sent one. We have been in contact with Omega for several weeks now trying to fix the issue and it has not been resolved.
Date published: 2021-03-11
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I have 3 questions. - Is it possible to measure the flow in reverse direction? - How long is the period at which data is recorded? - What is the resolution of model number FTB311D? Thank you!

Asked by: khan25
Thank you for your inquiry. Please email flow@omega.com and our Flow Engineers will be able to provide any additional information you need.
Answered by: AS Engineer
Date published: 2021-01-08

Does it display just the volume(gallon/litres) or can it display flow rate(gpm/lpm) as well?

Asked by: akasal
Thank you for your question? The FTB300 series Micro-Flow meters can display both volume and flow rate.
Answered by: application engineer je
Date published: 2020-07-22
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