V-Cone vs Venturi: A comparisonJanuary 29, 2021
The “V” in V-Cone® is often mistaken to mean “Venturi-Cone,” however, this is not the case. The “V” represents the shape of the cone in the meter itself, designed to measure flow via the Bernoulli principle. Both the V-Cone and the Venturi are differential pressure flow measurement devices, but beyond that, there are more differences than similarities.
Engineers will often find themselves comparing these two measurement devices when considering a meter for a new or existing flow project.
So how do these meters stand out?
By evaluating an application’s specifications and concerns, and how the meters addresses them, users can make the best-informed decision for a flow project.
Cost concerns and flexibility
The V-Cone requires minimal-to-no straight-run pipe to maintain up to ±0.5% accuracy, making it an ideal choice for users wanting to avoid re-piping an existing setup, or those with limited space. The Venturi requires a straight-run of 5 to 20 diameters upstream, on average, which may inflate a budget with additional piping to spec into the project.
Depending upon the project, exotic materials for construction might be imperative, adding cost. Flange to flange, a Venturi meter is dimensionally much longer than a V-Cone, so naturally a Venturi manufactured from exotic materials is more expensive than a V-Cone.
Both a Venturi meter and a V-Cone can be customized roughly the same amount in terms of end connections, pressure taps and the variety of materials. Cladding, the process of laying a more corrosive-resistant, generally more expensive metal on top of a cheaper material, may also be a viable solution for cost-savings.
Size can affect cost as well. Once a meter is manufactured over a 16 inch diameter, the V-Cone typically becomes more cost-effective, as the amount of raw material involved to manufacture the Venturi is greater than the V-Cone. The pitfalls of a large line-size Venturi, like excessive weight and size, can cause installation hassles and production costs to skyrocket.
The flexibility of the technology may also be what sways the decision to choose a V-Cone over a Venturi, or vice-versa. For customers anticipating or experiencing a wide range of flows, the V-Cone’s turndown ratio makes it an attractive solution. A V-Cone’s standard turndown ratio is 10:1 or higher, whereas a Venturi is typically 4:1, so if a wide range of flow rates is expected in the application, the V-Cone is a better fit for the project.
Meeting flow meter standards
Oftentimes, certain regulations and standards will determine which flow measurement solutions are available for implementation. Many companies require their flow meters to be manufactured and operated to ISO 5167, and both the V-Cone and Venturi can comply with this standard upon request. This standard ensures that the manufacturing of the meters meets certain specifications for straight-run requirements, site installation and more through calibration of the meter or dimensional check.
McCrometer meets the ISO 5167-5 standard for cone meters by dimensional check of the meter or by full calibration of the V-Cone over the entire Reynolds’ range. This allows the V-Cone to achieve its up to ±0.5% accuracy; McCrometer calibrates all meters it manufactures, so customers have confidence in their V-Cone’s performance.
The Venturi meter offers ±0.7% to ±1% accuracy when calibrated and is built to the ISO 5167-4 standard. However, if the meter is built to the standard but not calibrated, any irregularities in the pipe won’t be caught before the manufacturer ships it to the customer site, as there would not be testing of the meter prior to installation.
By choosing a V-Cone, customers are choosing peace of mind, as every V-Cone is wet-calibrated and arrives complete with a calibration report and list of inspection points. In addition to the ISO standards, V-Cone also meets other standards including the pressure equipment directive (PED) and other material standards. For additional information about the standards and regulations that McCrometer and their products meet, take a look at McCrometer’s blog covering the topic.
Industries and verticals
V-Cones as well as Venturi meters are popular in the oil and gas and energy sectors, as they are robust options for what are typically harsh environments. Depending on the individual application, however, choosing one meter over the other will become obvious.
The V-Cone is a popular choice for floating production storage and offloading (FPSO) units, as the meter’s straight-run requirements meet space and weight regulations of the floating vessel. Popular oil and gas applications that have high pressure lines need thicker-walled pipe, so every inch of pipeline adds significant weight to a vessel limited in real estate and structural load.
In smaller pipeline industrial applications, the lower-cost Venturi meter might be preferential to an engineer with plenty of space to run straight pipe, especially when the meter needed is less than a 16 inch diameter.
Custom meters for unique flow applications
As is typical for other meters, whether a V-Cone or a Venturi is selected, it is wholly dependent upon the needs of a flow project and what criteria must be met. What works for an offshore platform or a small retrofit project may not work for an industrial application requiring a large quantity of small line-size meters.
The good news: McCrometer’s team of expert engineers is available to discuss flow project requirements and determine if a custom V-Cone solution will work for its customers. For more information, check out the V-Cone product page or contact the factory for a quote.