Low loss, high turndown, HP gas flow meter.


The application required a flow meter to measure the flow of high pressure gas.

A large flow rate turndown was required (in excess of 20:1) and low permanent pressure loss was considered to be a major advantage

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The meter was designed to measure Hydrocarbon Gas flow produced by the Norne oil field in the Norwegian Sea.

With an operating pressure of 165 bar G and a flow rate turndown in excess of 20:1 the application posed a significant challenge.


The requirement was met using a bespoke design AptiFlow Averaging Pitot Tube which incorporated dual impulse connections, allowing two DP transmitters to be connected directly via integral five valve manifolds.

Dual Transmitter AptiFlow

Technical Considerations

The ranges of the two transmitters overlapped so that each transmitter corresponded to a flow turndown of approximately 5:1, thereby covering the 20:1 required turndown.


Performance Verification

The complexity of the design and the application’s challenge threw open a few questions regarding the product’s performance. Specifically, if the theory would be backed up in practice!

Fortunately, the National Engineering Laboratory (NEL) at East Kilbride, Scotland, were able to perform calibration tests and confirm the flow meters performance under known flow rates with high pressure gas.