KROHNE ALTOSONIC V12 Custody Transfer Ultrasonic Gas Flowmeter

Overview of the KROHNE ALTOSONIC V12

The KROHNE ALTOSONIC V12 is an ultrasonic transit-time gas flowmeter for fiscal and custody transfer measurement of natural gas. KROHNE introduced it as the world’s first 12-chord meter, and it was the first ultrasonic flowmeter to achieve OIML R137 class 0.5 approval. Its path configuration, dedicated diagnostic chords and remote expert system are designed for long-term accurate, stable measurement with a small footprint and low ownership cost, in sizes from DN100 to DN600 and pressure classes up to ASME 2500.

Seven Star LLC supplies the KROHNE ALTOSONIC V12 to gas producers, pipeline operators, power producers and metering skid fabricators across the Sultanate of Oman and the GCC. As a trusted supplier with engineering support in Muscat, we coordinate the application data for KROHNE’s sizing evaluation and support the integration of the meter with flow computers and metering system documentation.

Measuring Principle

The meter measures the transit time of ultrasonic pulses that cross the pipe between pairs of transducers. A pulse travelling with the flow arrives slightly earlier than one travelling against it, and the gas velocity is derived from this difference in transit time. The straight crossing of the pipe from one side to the other is called a chord, and by using reflections an acoustic path can be made of two or more chords. The name of the KROHNE ALTOSONIC V12 refers to its design, in which 12 chords form six acoustic paths arranged in five measurement planes.

Multiple planes and crossed paths give excellent immunity to swirl and asymmetric flow profiles, so only a 5D straight inlet is needed without a flow conditioner to comply with AGA 9, ISO 17089, OIML and MID. One chord is dedicated to diagnostics: the vertical chord detects very thin layers of condensate, water or solids at the bottom of the meter, contamination that conventional meters would only notice once it became a major blockage. Primary measured value is transit time; actual volume flow and totalised volume are calculated.

Engineering Design of the KROHNE ALTOSONIC V12

The meter body and flanges are made of low-temperature carbon steel A350 LF2 as standard, with stainless steel and duplex as options, and the outside receives a PSX 700 coating. Standard transducers are rated from −40 to +100 °C, while titanium transducers extend the process range to +175 °C. Meters of 6 inch and larger in classes up to ASME 900 are equipped as standard with transducers that can be retracted under pressure, which allows service without depressurising the line.

The signal converter of the KROHNE ALTOSONIC V12 sits in a stainless steel 316 housing on top of the meter body, rated IP66/67 and NEMA 4X, with a 256 × 128 pixel display and four optical keys. It provides four digital outputs, two isolated Modbus RS-485 ports, Ethernet and a 4–20 mA output, and can emulate a turbine meter pulse output. The optional KROHNE Care board adds further outputs, a HART input and the web-based expert system. Power is 24 V DC with a consumption of up to 12 W.

Key Features

The KROHNE ALTOSONIC V12 provides the following capabilities documented in the technical datasheet:

• 12 chords in five planes, with OIML R137 class 0.5 and class 1.0 approval and MID type examination.
• Accuracy of ≤±0.1 % of measured flow after high-pressure calibration with linearisation, and repeatability better than ±0.05 %.
• No flow conditioner and only 5D straight inlet required for AGA 9, ISO 17089, OIML and MID compliance.
• Dedicated vertical chord for bottom-fouling detection and predictive maintenance.
• KROHNE Care web-based expert system running 24/7 inside the electronics, accessible from a standard browser.
• Nominal sizes DN100 to DN600 and pressure range 1 to 450 bar (ASME 150 to 2500).
• Variants including V12 Direct for high CO2 gas, V12 Check with integrated check measurement and V12 Twin with two independent custody transfer meters.
• ATEX Zone 1, Class I Division 1 and 2, NEPSI and EAC hazardous-area approvals.

Industrial Applications

KROHNE designed the instrument for natural gas transmission, metering and regulation stations, liquefaction and regasification, border stations, underground storage and on- and offshore exploration, with nitrogen, hydrogen and CO2 also listed. In Oman, the KROHNE ALTOSONIC V12 matches fiscal and allocation metering on the national gas transmission network, gas sales points to power and desalination plants, LNG feed gas in Sur, and custody transfer between upstream operators and industrial consumers in Sohar and Duqm. The Twin variant gives two independent measurements in one spool for duty and check metering.

Metering skids built in the GCC typically combine the meter with pressure and temperature transmitters, gas chromatographs and flow computers. Seven Star LLC supplies the KROHNE ALTOSONIC V12 alongside the KROHNE SUMMIT 8800 flow computer, and for non-fiscal gas duties the KROHNE OPTISONIC 7300 ultrasonic gas flowmeter, while liquid lines can use the KROHNE OPTISONIC 3400 ultrasonic flowmeter.

Technical Specifications of the KROHNE ALTOSONIC V12

The data below for the KROHNE ALTOSONIC V12 are taken from the KROHNE technical datasheet TD ALTOSONIC V12 R05 (05/2025); flow ranges are given in the metrological certificates.

How to Order

To obtain a quotation for the KROHNE ALTOSONIC V12, send Seven Star LLC your RFQ with the gas composition, CO2 content, operating pressure and temperature range, minimum and maximum flow, line size and flange rating, required approvals and calibration requirements. Our instrumentation division in Muscat will arrange the KROHNE sizing evaluation, confirm the variant and check delivery options and lead time. The technical datasheet can be downloaded from this page, and our engineers support metering projects across Oman and the GCC.