DON - Positive-Displacement Flow Meters

Brand: KOBOLD Instruments, Inc

KOBOLD's DON Oval Gear Positive Displacement Flow Meters are the ideal solution for measuring clean high and low viscosity liquids such as lubricating/hydraulic oils, petroleum, ink, diesel fuels, grease, chemicals, solvents, resins, pastes, and molasses. 

Due to the mechanical nature of the operating principle, media with particulate matter is not recommended for use with the DON.

The heavy-duty industrial oval gear design design employs two precision-machined gears that are turned by the force of the flowing media and they allow a very specific known volume of liquid to pass through the meter with each rotation. 

These gears enable the DON to precisely measure liquid flow over a very wide viscosity range and provide a high accuracy volumetric flow rate measurement. 

Visit our article about Positive Displacement Flow Meters to learn all about the technology type and its advantages and limitations.

Because the measurement principle provides a true volumetric flow measurement, the DON is also ideal for flow rates that fluctuate widely and for flow that is intermittent. 

High accuracy measurement is assured even though these are process variables that would render other flow meter technology types non-compatible.
  • Aluminum or Stainless Steel Bodies
  • Can Measure Viscosities to 1,000,000 cPs (w/Special Cut Gears)
  • Operating Pressures to 1,450 PSIG (Model Dependent)
  • Electronic Output Options Include Analog and Frequency Outputs, LCD Totalizers and Batch Controllers
  • Mechanical Totalizer
  • Bi-directional Flow Sensing with Optional Quadrature Output
  • Certifications/Approvals: ATEX
  • Top Seller


Flow Ranges

  • 0.13-9.5 GPH to 40-660 GPM

Line Sizes

  • 1/8” to 4”


  • NPT or BSP Threaded
  • ANSI or DIN Flanged

Maximum Operating Temperature

  • 300° F

Media Categories

  • Liquid


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