V-Cone Flowmeter Suits Challenging Applications

The McCrometer V-Cone flowmeter is said to be suitable for a range of installations, from challenging offshore oil-and-gas applications to refining and chemical plants. According to the company, the flowmeter provides superior flow measurement, reliability, low-cost installation, virtually no maintenance and a long life. The instrument is suitable for oil-and-gas process engineers requiring a low-installed and low-lifecycle-cost solution for measuring liquids, gas or steam.

The process of selecting and sizing a V-Cone is claimed to be as simple as reviewing a configuration sheet and utilising the advanced McCrometer V-Cone Sizing Software. The entire selection process takes only minutes for most standard oil-and-gas applications. With its flexible design, various custom V-Cone configurations are also available. The flowmeter operates over a wide flow range of 10:1 with low head loss and supports line sizes from 0.5in (1.3cm) to more than 120in.

The accuracy of the flowmeter is 0.5 per cent, while its repeatability is 0.1 per cent. A suite of testing is available to meet individual user requirements, including pressure, non-destructive testing and calibration. The testing of the V-Cone conforms to the American Petroleum Institute API 22.2 Testing Protocol for differential-pressure flow-measurement devices.

The self-conditioning V-Cone flowmeter is suitable for situations where installation conditions are crowded, such as offshore platforms. It requires a pipe straight-run that is up to 70 per cent less than other meters, resulting in real-estate and installation cost savings that can exceed the price of the instrument itself. The no-moving-parts design provides built-in flow conditioning, which almost eliminates the upstream/downstream straight-pipe runs required by nearly all flowmeter technologies.

Typical flowmeter installations may require 10 to more than 40 straight-pipe diameters upstream from the meter and five or more straight-pipe diameters downstream to eliminate the effects of swirl and other pipeline disturbances caused by valves or elbows that negatively affect accuracy. In comparison to traditional differential-pressure instruments such as orifice plates and Venturi tubes, the V-Cone flowmeter design is inherently more accurate because the flow-conditioning function is built into the basic instrument, according to McCrometer. The V-Cone conditions fluid flow to provide a stable flow profile that increases accuracy.

It features a centrally located cone inside a tube; the cone interacts with the fluid flow and reshapes the velocity profile to create a lower-pressure region immediately downstream. The pressure difference, which is exhibited between the static line pressure and the low pressure created downstream of the cone, is measured via two pressure-sensing taps. One tap is placed slightly upstream of the cone and the other is located in the downstream face of the cone itself. The pressure difference is then incorporated into a derivation of the Bernoulli equation to determine the volumetric fluid flow rate.