KROHNE OPTISONIC 3400 Ultrasonic Flowmeter

Overview: Multi-Purpose Ultrasonic Measurement Without Moving Parts

The KROHNE OPTISONIC 3400 is a 3-path inline ultrasonic flowmeter designed for homogeneous, non-viscous aqueous liquids as well as viscous fluids of up to over 1,000 cSt, covering standard process applications through to demanding cryogenic (as low as -200°C) and high-temperature (up to +250°C) service. As a main KROHNE product for ultrasonic in-line process flowmeters, the OPTISONIC 3400 combines a large installed base with a proven record of robustness and measurement accuracy across chemicals, petrochemicals, oil and gas, energy, and water utility applications.

As an authorized supplier of KROHNE flow instrumentation, Seven Star LLC sources and supplies the OPTISONIC 3400 ultrasonic flowmeter to refineries, water utilities, and petrochemical facilities across Oman and the wider GCC. Because ultrasonic metering with no moving parts eliminates the wear-related maintenance associated with mechanical flowmeters, Seven Star LLC helps engineering teams specify the correct diameter, pressure class, and process connection for their measurement point.

Measurement Principle

The OPTISONIC 3400 measures flow using three parallel ultrasonic acoustic paths across the pipe bore, transmitting and receiving ultrasonic pulses between transducer pairs positioned at an angle to the flow direction. Because the fluid’s motion speeds up sound travel in the direction of flow and slows it in the opposite direction, the flowmeter calculates flow velocity from the difference in transit time between upstream and downstream pulses, and this velocity is converted into volumetric or mass flow using the pipe’s known cross-sectional area.

The three-beam design measures continuously and starts measurement at nearly zero flow, supporting a high turn-down ratio suited to pipeline transportation measurement as well as demanding fiscal applications. A distinctive OPTISONIC 3400 feature is its free-of-charge measurement of velocity of sound per acoustic path, which can reveal information about liquid contamination or changing process conditions without requiring any additional instrumentation. Diagnostic functions conforming to NAMUR NE107 provide extensive self-checking of internal circuits along with health status of the measuring sensor and process conditions.

Engineering Design of the OPTISONIC 3400

The OPTISONIC 3400 is built with completely welded construction that is wear- and maintenance-free, and its full-bore, unobstructed sensor tube introduces no pressure loss and contains no moving parts to wear or foul. The flowmeter covers a broad diameter range from DN25 (1 inch) for dosing applications up to DN3000 (120 inch) for large water transportation pipelines, with pressure classes from ANSI 150 through 900 and process temperatures spanning -328°F to +482°F (-200°C to +250°C).

An advanced signal converter provides a full range of I/O options and communication protocols, with an improved user interface using optical and push buttons for field configuration without opening the enclosure under hazardous-area conditions. Bi-directional flow measurement is supported over a wide dynamic range, and dedicated versions are available for both conductive and non-conductive liquids, giving specifiers flexibility across a broad range of process media. Approvals include ATEX, IECEx, cCSAus, and NEPSI for use in classified hazardous areas.

Key Features

The KROHNE OPTISONIC 3400 delivers accurate, low-maintenance flow measurement across a wide range of liquid applications. Key characteristics include:

• 3-path ultrasonic measurement with accuracy of ±0.3% plus 2 mm/s.
• Diameter range from DN25 (1 inch) to DN3000 (120 inch).
• Process temperature range from -200°C to +250°C (cryogenic to high-temperature service).
• Completely welded, wear-free construction with full-bore, unobstructed sensor tube.
• Bi-directional flow measurement with high turn-down ratio, measuring continuously from near-zero flow.
• Free velocity-of-sound measurement per acoustic path for process condition diagnostics.
• NAMUR NE107-compliant diagnostics with extensive internal self-checking.
• ATEX, IECEx, cCSAus, and NEPSI approvals for hazardous-area installations.

Industrial Applications

The OPTISONIC 3400 is deployed across chemical and petrochemical plants, oil and gas midstream pipelines, energy sector applications, and water utilities including boiler feedwater, demineralized water, and make-up water systems. Its wide turn-down ratio and broad temperature and pressure range make it well suited to transportation pipeline measurement, allocation measurement in on/off-loading, and both standard and high-performance flow measurement applications on the same platform.

Seven Star LLC supports refinery instrumentation teams, water authorities, and petrochemical maintenance departments across Oman, Muscat, Sohar, and the broader GCC region with sourcing of KROHNE OPTISONIC 3400 ultrasonic flowmeters, helping projects achieve reliable, low-maintenance flow measurement across demanding process conditions.

Technical Specifications

The table below summarizes the core specifications of the KROHNE OPTISONIC 3400 Ultrasonic Flowmeter as supplied by Seven Star LLC.

Call To Action

Seven Star LLC supplies the KROHNE OPTISONIC 3400 ultrasonic flowmeter with full manufacturer documentation and regional technical support. Contact our instrumentation division for a formal B2B quotation, to confirm the correct diameter and pressure class for your pipeline, or to obtain the complete technical datasheet. Seven Star LLC ensures every unit shipped across Oman and the GCC is genuine KROHNE hardware, correctly specified, and backed by local support.