COIN Wedge Flow Meters

The Preso COIN Flowmeter accommodates most flows, even the most abrasive.  Accuracy and reliability are achieved by its rugged construction, practical design, and simple principle of operation.  It stands alone in its ability to maintain the necessary square root relationship between flow rate and differential pressure for almost any type of flow:

  • Clean Liquids
  • High Viscosity Fluids
  • Steam
  • Slurries
  • Corrosive Processes
  • Gas/Air
  • Custom designs available

Even viscosity up to 3,000 centipoise does not affect the accuracy of the COIN flowmeter. The flow coefficient stays highly predictable down to the remarkably low Reynolds number of 300. This makes the series COIN flowmeter ideal for such traditionally difficult-to-meter applications as fuel oil, waste water, coal tar, iron ores, black liquor, and others.

Preso COIN Principle of Operation The basic flow equation for the COIN series is derived from BERNOULLI’s THEOREM (energy balance and the continuity equations). An engineered restriction creates a differential pressure that equates to a mass or volumetric rate of flow. Different height (H) over diameter (D) ratios are specified to handle different flow ranges.

A COIN flowmeter can solve your most difficult flow measurement applications. You get accurate, reliable results from the COIN flowmeter.


  • Pipe size: 1/2…48 in. and larger upon request (13…1219 mm)
  • Custom designs available
  • Suitable for abrasive slurries, viscous or dirty fluids   such as bitumen or coal tar
  • Accuracy: ± 0.5% of readings (calibrated) ± 3% of readings (uncalibrated) calibrated at CEESI, Alden, NRCC, NIST traceable laboratories
  • Mass flow output with multivariable transmitter (accuracy ± 0.5% calibrated)
  • Repeatability: ± 0.2% of readings
  • Turndown Ratio: 10/1
  • Very low Reynolds number measurements (down to RE # 300)
  • Low Pressure Losses
  • Reduced Pumping Costs
  • Very high viscosity measurements (500, 1000, 3000 centipoise and higher)
  • Resists wear, maintenance free (no moving parts)
  • Short form, lighter weight than classical Venturi Meters
  • Bi-Directional flow measurement
  • Easily installed in any position with minimal straight pipe requirements (5 pipe diameters upstream and 2 pipe diameters downstream)
  • Manufactured to standards such as: ASME, ANSI B31.1, NACE MR-0175and CSA-Z299.3 or equivalent
  • ISO-9001 certified design and fabrication