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Differential pressure (DP) flowmeters are among the most traditional of flowmeters. Their large installed base means that they still exert a powerful force on the flowmeter market.
The DP flowmeter market appears to be holding its own, and possibly gaining ground, when other traditional technology flowmeters such as turbine meters are losing market share. There are several reasons for
this:
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DP flowmeters still have the largest installed base of any type of flowmeter.
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Pressure transmitter suppliers have been very active in incorporating technological improvements into their products.
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The development of
multivariable DP transmitters and flowmeters has enabled customers to save money and reduce installation costs.
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Like vortex flowmeters, DP flowmeters are very versatile, and can be used to measure liquid, gas, and steam flows.
Links
to DP transmitter suppliers
More info on DP
flow: www.FlowElement.com
and www.dpmeter.com
Measuring
DP flow -- not so straightforward
Determining the market size for a flowmeter can be fairly
straightforward when it is clear what is included in the flowmeter. Most flowmeters have a sensor and a transmitter, along with an amplifier, transducer, and display. Typically, the transmitter generates one or more output signals that represent flowrate, and can represent other values such as pressure or temperature.
DP flowmeters, however, are different because of the complexity of the measurement. DP flowmeters require some type of constriction in the flowstream, created by a primary element. They require a DP transmitter to provide a reading of the difference in line pressure upstream and downstream from the constriction. The primary element is essential to making the DP flow measurement. But often end-users order the primary element separately from the DP transmitter, and from a different supplier, so tracking primary element sales values can be a challenge.
Types of primary elements include orifice plates, Venturi tubes, averaging Pitot tubes, flow nozzles, laminar flow elements, and wedge elements. The costs associated with these products should be included in the total value of the DP flowmeter market. Simply considering the value of DP transmitters is not sufficient. And when the value of primary elements is included in the DP flowmeter market, it is among the largest of any flowmeter market in terms of revenues.
When to choose a DP meter
DP meters excel at measuring clean liquids, steams, and gases when:
- Pressure drop is not a major issue. DP flowmeters cause varying amounts of pressure drop, depending on the type of primary element used. Orifice plates cause substantial loss of line pressure, while averaging Pitot tubes cause less.
- An application requires low to medium accuracy. Although accuracy varies with the type of DP technology, DP flowmeters are considerably less accurate than new-technology flowmeters.
- Price is a consideration. DP flowmeters are considerably less expensive to buy than most Coriolis and ultrasonic meters.
Many end users of DP transmitters today are facing a dilemma. Should they upgrade to new-technology flowmeters or stick with tried-and true-DP meters? Of course, some
end users at large plants may choose to upgrade some of their DP meters, and stick with DP technology elsewhere in the plant. Instead of replacing all their DP meters, they may make this decision on a case-by-case basis.
Here
to stay
DP flowmeters are here to stay, and will continue to provide stiff competition to new-technology flowmeters. And the market might be even stronger if suppliers would look more seriously at primary elements. What the world needs now is some new and improved primary elements to go with those highly stable and accurate pressure transmitters. Only when suppliers work to improve primary elements as they have worked to improve pressure transmitters will we know the true potential of the DP flowmeter market.
Previous Studies:
The
World Market for Differential Pressure (DP) Flowmeters and Primary Elements
Released in
January 2007
The
World Market for DP Flow Transmitters
Released in
September 2007
The
World Market for Primary Elements
Released in
September 2007
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