Small Volume Unidirectional Captive Displacement Prover


Flow Management Devices’ FMD 003 Unidirectional Captive Displacement Prover provides exceptional accuracy and rangeability. With standard 2” ANSI B16.5 flanges on both the inlet and outlet and a flow range capability of up to 300 GPM* (428 BPH, 68 M3/HR), and a 1200:1 turndown, this prover is an exceptional choice for your application.

Download PDF Data Sheet Request Quote


Max flow rate GPM BPH M3H
300 428 68
Displaced Volume Gallons Liters
Primary Secondary Primary Secondary
2 1 7 4
Turndown Std Flange Size Standard Materials of Construction
1200:1 2” ANSI – 150#, 300#, 600# or 900# 304, 316 and Duplex Stainless


  • Accuracy: < 0.02% - Exceeds API Standard
  • Performance: Exceeds 0.02% ISO17025 Calibration Lab
  • Pressure Drop: 5 psi at max flow rate of each prover (calculated with water)


  • Conforms to API 4.2 and API 4.6
  • Galvanized frame per ASTM A123/123M-02
  • Shock mounted isolation pads for independent drive and support
  • 3-point installation for secure mounting on uneven surfaces
  • 3/4” connection flanges for rapid draining
  • 3/4” vents with check thermowell and pressure verification ports
  • All wetted parts stainless/PTFE
  • Prover Interface Module (PIM) with advanced features
  • Smooth Belt Drive with clutch
  • Shock mounted Isolation Pads

Flow Management Devices’ goal is 100% Customer Satisfaction: therefore, we provide the following at no charge.

  • Four-year warranty for parts (seals and seal changes are not included)
  • Final Acceptance Testing (Includes: Water Draw, Hydrostatic & Dielectric Testing)
  • Training in our facility during Final Acceptance Testing
  • Free crating per ISPM-15 (Stationary only)
  • One day onsite startup and training


  • ISO 9001/2008
  • ISO 17025
  • CSA/US Class 1 Div. 1
  • CRN
  • ATEX
  • GOST (Russia)
  • Kazakhstan Metrology

*When sizing a flow meter for this prover, the maximum flow rate should be less than or equal to the maximum rate of the prover. All the FMD Small Volume Provers can operate at the maximum flow rates as specified. Nominal flow rates should not exceed 80% of maximum, all application information should be verified with FMD and will vary due to the meter technology used in each application.

** Displace Liter Volume values are not a direct conversion from gallon values. Prover requires non-standard switch bar for liters.