Many changes are occurring in the worldwide flowmeter market. While growth of new-technology flowmeter applications continues to outpace those of more traditional meters, long-term favorites such as turbine and positive displacement are holding their own in many applications.
For now at least, change is evolutionary rather than revolutionary. This article looks at significant developments occurring in each of 10 flow technologies.
These types of meters, introduced since 1950, include Coriolis, magnetic, ultrasonic, vortex, and multivariable differential pressure (DP). They are the main focus of product development by the major suppliers, and typically have accuracy levels of 1% or better. Sales of all of these types are growing at a compound annual growth rate (CAGR) faster than the flowmeter market as a whole (greater than 2.1%).
* The Mystery Meter: The first Coriolis meters featured bent tubes. However, since straight-tube meters were introduced in the mid-1990s, much of the product development has been focused on them. Straight-tube Coriolis meters are especially suited for sanitary applications, since they are easier to clean than bent-tube meters. Particles are less likely to get lodged in straight-tube than in bent-tube meters.
Line size continues to be an issue for Coriolis meters. More than 90% of Coriolis meters sold are 2 in. or less in size. Coriolis meters become expensive and unwieldy in larger line sizes, especially 4 in. and above. No one has as of yet been able to invent a Coriolis meter for the larger line sizes that is modest in both price and size.
One of the most interesting new Coriolis products is Foxboro's digital Coriolis meter, the CFT50. This meter is designed to deal with measurement applications involving two-phase flow, such as liquid and gas, or entrained air. The meter was developed as the result of a customer needs analysis in conjunction with the engineering department at the University of Oxford. It can handle difficult-to-measure applications including slurries and non-homogeneous fluids, as well as pharmaceutical batch applications, railcar and tank truck unloading, pulp & paper coating applications, and dairy processes in cheese manufacturing.
End users have a unique loyalty to Coriolis meters. This may stem from admiration for their high accuracy together with the inability to see the inner workings of the meter. This gives Coriolis meters a sense of mystery that no other meter has. Despite this, in interviews end users have requested a sight glass to visually check flow on Coriolis flowmeters.
* A Magnetic Attraction: Magnetic flowmeters (Figure 1) are the workhorses of the flowmeter market. They are wildly popular in Europe, where there is great need to measure water flow, and the leading suppliers are based in Europe. In fact, magnetic flowmeters were first introduced in Holland in 1952.
Figure 1: Tall to Small
Photographed at Krohne's calibration facility in Dordrecht, Holland, the author shows magnetic flowmeters are commonly used in an extensive range of sizes.
Because magnetic flowmeters are so widely used for sanitary applications, much of the new product development either centers around linings or around meters designed for particular applications. Application-specific meters typically meet certain industry standards and are designed with materials suited for a particular industry. An example is Emerson Rosemount's Model 8721 sanitary magnetic flowmeter.
More money is spent on magnetic flowmeters annually than on any other type. This is projected to remain true through 2007. In terms of units, there are far more magnetic flowmeters sold than any other type of new-technology meter. More than twice as many magnetic flowmeters are sold in Europe than in the U.S. It appears, then, there is a certain magnetic attraction between end users and these flowmeters.
* The Ultra-Fast-Growing Meter: Ultrasonic flowmeters are the fastest growing meter category. However, most of this growth comes from explosive growth in the market for custody transfer of natural gas. This growth began in Europe in 1995 with the publication of Technical Monograph 8 by Groupe Europeen de Recherches GaziSres (GERG). This monograph laid out criteria for using ultrasonic flowmeters for custody transfer of natural gas. In June 1998, the American Gas Assn. (AGA) followed suit with a similar document, AGA-9, which resulted in explosive growth of ultrasonic meters for that application in North America.
While natural gas measurement has captured many of the headlines, some important developments have been occurring on the liquid side. The American Petroleum Institute (API) has published a draft standard about using transit-time ultrasonic flowmeters to measure liquid hydrocarbons. Krohne recently introduced the UFM 3030, a three-beam transit-time ultrasonic flowmeter designed to measure liquids, including hydrocarbons. That unit is a follow-up to the company's AltoSonic V, the first multiple-beam ultrasonic flowmeter for custody transfer of liquids.
* A Plethora of Vortices: Vortex flowmeters have so far failed to capture the imagination of the end user community. While they have many attractive features, they do not have one overriding strength that makes them a must-have for a particular application. They are highly accurate, but not as accurate as Coriolis meters. And while they are minimally intrusive, they are more intrusive than magnetic and ultrasonic meters.
Vortex meters are at their best in steam applications because they can handle the high pressures and temperatures associated with measuring steam flow. However, steam only accounts for about 10% of total flow applications. Perhaps this is why vortex meters are currently the slowest growing new-technology segment.