KROHNE OPTIMASS 6400 Coriolis Mass Flow Meter

Overview

The KROHNE OPTIMASS 6400 is the manufacturer’s standard high-performance Coriolis mass flow meter for the process industry, built around a twin bent tube sensor design that delivers exceptional accuracy across an unusually broad range of process conditions. From routine process control in petrochemical plants to concentration measurement in food and beverage production, and from custody transfer filling stations to marine fuel bunkering, the KROHNE OPTIMASS 6400 is engineered to handle demanding, high-value flow measurement duties where every fraction of a percent of accuracy translates directly into commercial value. Its high-end configuration options extend its reach to cryogenic media such as liquefied natural gas at temperatures down to −200°C, as well as high-temperature process lines up to +400°C and high-pressure service up to 200 bar / 2900 psig.

As an authorized partner for KROHNE instrumentation in Oman, Seven Star LLC supplies the KROHNE OPTIMASS 6400 to process plants, refineries, marine terminals, and utility operators across Muscat, Sohar, Salalah, and the wider GCC region. Facilities in Oman’s petrochemical and LNG export corridors rely on Coriolis technology precisely because it measures mass flow directly, independent of pressure, temperature, density, or viscosity changes — a critical advantage for custody transfer accounting and fiscal metering where local authorities and international trading partners demand certified precision. We provide genuine KROHNE hardware backed by application engineering support, ensuring every KROHNE OPTIMASS 6400 installation is correctly specified for the process media, line size, and hazardous area classification at hand.

Measurement and Operating Principle

The KROHNE OPTIMASS 6400 measures mass flow using the Coriolis effect: process fluid is directed through twin curved measuring tubes that are driven into oscillation at their natural resonant frequency by an electromagnetic actuator. As fluid moves through the vibrating tubes, the Coriolis force induces a measurable phase shift (time delay) between the inlet and outlet legs of the tube, and this phase shift is directly proportional to the mass flow rate passing through the sensor. Because the measurement is a direct physical consequence of mass and velocity rather than an inferred calculation, the KROHNE OPTIMASS 6400 requires no separate pressure or temperature compensation to deliver mass flow, and it simultaneously derives fluid density and, using the integrated temperature sensor, volumetric flow at reference conditions from the same vibrating-tube signal.

A defining capability of the KROHNE OPTIMASS 6400 is Entrained Gas Management (EGM™), which allows the meter to maintain stable, usable measurement even when the process medium contains up to 100% intermittent gas entrainment — a condition that causes conventional Coriolis meters to lose signal lock entirely. Combined with an optimised flow splitter that minimizes pressure loss and a twin bent tube geometry that is self-draining when mounted vertically, the sensor resists installation effects and crosstalk, meaning it delivers consistent readings regardless of upstream piping disturbances. Fully digital signal processing supports HART 7, Modbus, FOUNDATION Fieldbus, PROFIBUS PA/DP, PROFINET (including Ethernet-APL for hazardous areas), EtherNet/IP, and secure Bluetooth® connectivity for commissioning and diagnostics without opening the enclosure.

Engineering Design of KROHNE OPTIMASS 6400

Mechanically, the KROHNE OPTIMASS 6400 sensor is available in line sizes from DN10 to DN300 (½” to 12″) and in three wetted materials — 316L stainless steel, Hastelloy C-22, and Duplex UNS31803 — allowing the meter to be matched to corrosive, cryogenic, or high-purity process media. Pressure ratings extend to PN160 / ASME Class 1500, and the sensor is offered in compact (integral transmitter) and remote field-mount configurations to suit installations where ambient temperature, vibration, or access constraints make a separated transmitter preferable. Optional heat tracing jackets and purge ports extend suitability to viscous or temperature-sensitive products, while hygienic clamp-connection variants support food, beverage, and pharmaceutical duty.

On the safety and certification side, the KROHNE OPTIMASS 6400 is SIL 2/3 certified up to DN200 with partial proof test coverage of up to 82%, making it suitable for direct integration into safety instrumented systems without a separate certified transmitter. For fiscal and custody transfer service, it holds OIML R117, R137, MI-005, and MI-002 approvals along with API and AGA compliance, achieving the highest OIML accuracy class of 0.3 — the level of precision required for revenue metering of oil, gas, and LNG. On-site verification is supported by KROHNE’s OPTICHECK diagnostic tool, letting maintenance teams confirm calibration integrity in the field without removing the meter from the line, which materially reduces downtime for plants running continuous operations.

Key Features

• Twin bent tube Coriolis sensor with ±0.05% mass flow accuracy for liquids and gases
• Entrained Gas Management (EGM™) maintains measurement with up to 100% intermittent gas entrainment
• Operating range from −200°C to +400°C, supporting cryogenic LNG through high-temperature process duty
• Pressure rating up to 200 bar / 2900 psig, line sizes DN10–DN300
• SIL 2/3 safety certification with up to 82% partial proof test coverage
• OIML R117 custody transfer accuracy class 0.3, plus API and AGA compliance
• Available in 316L stainless steel, Hastelloy C-22, and Duplex UNS31803 wetted materials
• HART 7, Modbus, FOUNDATION Fieldbus, PROFIBUS, PROFINET/Ethernet-APL, EtherNet/IP, and Bluetooth® connectivity

Industrial Applications

The KROHNE OPTIMASS 6400 is deployed across the full spectrum of custody-critical and process-critical flow measurement duties: fiscal metering skids at oil and gas export terminals, LNG loading and marine bunkering operations, batch and blending control in petrochemical plants, and concentration measurement in food, beverage, and pharmaceutical production. Its resistance to entrained gas makes it especially valuable in applications where two-phase flow is unavoidable, such as pipeline pigging operations, tank truck loading, and chemical dosing lines where cavitation or aeration would otherwise compromise measurement integrity.

In Oman, Seven Star LLC supplies the KROHNE OPTIMASS 6400 to refineries, LNG facilities, and marine terminals in Sohar and Salalah, as well as to water treatment and chemical processing plants throughout the Muscat industrial corridor and the wider GCC. As an authorized KROHNE partner, we support project engineers and plant operators with correct sizing, hazardous area certification matching, and integration guidance for HART, fieldbus, and Ethernet-APL networks, ensuring the meter performs to its certified accuracy from commissioning through years of continuous custody transfer or process control service.

Technical Specifications

Ready to specify the KROHNE OPTIMASS 6400 Coriolis mass flow meter for your project in Oman or the GCC? Contact Seven Star LLC for genuine KROHNE hardware, technical sizing support, and fast regional delivery.