OPTISONIC 3400 Ultrasonic Flowmeter

Source: KROHNE, Inc.

The OPTISONIC 3400 is a 3-path ultrasonic inline flowmeter designed for a wide range of standard or more demanding process applications with homogeneous, non-viscous aqueous liquids as well as viscous fluids of up to over 1000 cSt. It is also the perfect choice for applications with cryogenic products (as low as -200°C / -328°F), media with extended temperature ranges (up to +250°C / +482°F) as well as low or extreme pressure ratings. The OPTISONIC 3400 offers a broad range of diameters – from DN25 / 1" for dosing purposes to DN3000 / 120" for water transportation pipelines.

Based on the transit time method, the 3 parallel acoustic paths of the flowmeter allow bi-directional measurement independent of flow profile for high accuracy even under less favourable flow profile conditions (e.g. short inlet and outlet runs). By means of the velocity of sound, the device is also able to identify process changes or liquid pollution. Its fully welded construction does not cause any pressure loss and is maintenance-free. The OPTISONIC 3400 is available with flange as well as welded connections. It features enhanced diagnostics and provides various digital communication options.

Product highlights

  • Bi-directional flow measurement over a wide dynamic range
  • Various dedicated versions for many industrial applications with conductive or non-conductive liquids
  • For extended process temperature ranges
  • Low or extreme pressure ratings available
  • No influence of scaling due to direct path configuration
  • Extensive sensor and process diagnostics (incl. NE 107)
  • Optional heating jacket
  • Full bore design: No moving parts, no wear, no pressure loss
  • Various digital communication options
  • Compact or field-mounted version (incl. cable length up to 30 m / 90 ft, optional IP68 rated)

Typical applications


  • Cryogenic- and high process temperature applications
  • Applications with high process pressures
  • Various conductive and non-conductive aqueous or viscous liquids

Oil and gas industry

  • High viscosity liquid hydrocarbons
  • Water/chemicals injection
  • Produced water
  • Allocation metering
  • Pipeline metering
  • Pipeline leak detection
  • Product identification
  • Liquefied Natural Gas (LNG)
  • Corrosive and abrasive liquids

Chemical and other process industries

  • Almost all chemicals (including viscous media)
  • Biofuels
  • De-ionized, demineralised or cooling water
  • Blending
  • Molten sulphur
  • Chemical injection product
  • Product identification
  • Leak detection
  • Batching
  • Truck and ship loading

Conventional and nuclear power industry

  • Cooling water
  • Heat measurement
  • Condensate and boiler feed water

Water and wastewater industry

  • Abstraction influent/effluent, hot water/district heating, desalination, leak detection
  • Water distribution monitoring
  • Influent and effluent
  • Desalination
  • Leak detection

Marine industry

  • Tanker loading and off-loading

Machinery and apparatus (OEM industry)

  • Machine building
  • Greenhouses