Going with the future of flow
Why should there be a concern about measurement accuracy? The answer to this question lies in the answer to, why measure flow? Flow measurement requires reasonable accuracy to monitor and improve process efficiency, quality, and safety. Investments are made in flowmeters with the expectations of receiving a return that exceeds costs associated with installation.
Why should there be a concern about measurement accuracy? The answer to this question lies in the answer to, why measure flow?
Flow measurement requires reasonable accuracy to monitor and improve process efficiency, quality, and safety. Investments are made in flowmeters with the expectations of receiving a return that exceeds costs associated with installation. Flowmeters that 'work' but do not 'work accurately' may not achieve their potential return, according to D.W. Spitzer, in Practical Guides for Measurement and Control , 1991, Instrument Society of America.
'Many industries are turning to new and different materials and processes to produce a new generation of high-quality flow measurement products,' says Timothy W. Scott, vp business development at Brooks Instruments (Hatfield, Pa.).
'To assure success, there's a real need to employ more stringent low flow measurement and control methods,' adds Mr. Scott.
Marc Cartier, applications engineer for GF+Signet, agrees that the industry is changing. 'Manufacturers who can offer their products in various material types, provide the ability to meet changing application requirements.
'The practical realty is that most processes still remain unmonitored and misunderstood; the race is on to provide the ability to cost-effectively measure and capture real-time flow information,' says Mr. Cartier.
Control Engineering surveyed 1,500 readers, in part, to determine the types of flowmeters in use; examine the communication protocol; and identify characteristics most important to the end-user. Three hundred twenty-eight completed the survey for a 22% overall response rate.
Eighty-one percent of the 328 respondents recommend, specify, and/or buy flowmeters for in-plant requirements. While 11% do so for OEM requirements
How are these meters applied?
Ninety-five percent of respondents' flowmeter applications were for full flow pipe, while 31% were for open channel or partial flow pipe.
According to CE 's 1999 'Product Focus' on flowmeters, orifice meters-owing to their simple construction, relatively low cost, and lack of moving parts -were the most widely used. Mass flowmeters' performance was favored because of their accuracy despite changing fluid parameters, such as density, viscosity, pressure and/or temperature. Turbine and magmeter were also popular choices. ( CE , March 1999, p. 139).
What a difference a year makes. Forty-eight percent of respondents preferred magnetic flowmeters, 45% mass, 44% orifice, and 40% turbine. There was a slight increase in using Coriolis flowmeters at 36%. (See graph).
Five to seven years of changes have influenced product preferences, suggests Brian Hayes, manager, flow business unit at ABB Automation (Wickliff, O.).
'Customers want to install the product and have that be the last time maintenance is needed. They stay away from anything requiring moving parts. More sophisticated units are requested, such as having all diagnostics built-in,' says Mr. Hayes.
Glen Fishman, director of sales and marketing for FCI (San Marcos, Calif.) agrees on customers' needs. 'People want low maintenance and high repeatability in flowmeters. They want something to count on day in and day out, which also has ease of use.'
Future of flow
Companies agree that many factors will go into standardizing future flowmeters, from changing communication protocol, controlling flowmeters, to cost.
While improved reliability, accuracy, and ease of calibration were the three most important characteristics to respondents, nearly two-thirds (64%) felt improved reliability also was very important.
Similar to last year's product focus, standard input remains 4-20 mA at 83% currently in use. The next closest competitor is the 0-10 V signal at 25%, and HART with 22%. (See graph).
'In Europe, a much greater demand exists for communicating and controlling flowmeters. It's a lot like the appliance industry. Years ago, when smart appliances were coming out, Europeans quickly adapted to them. Americans didn't. Maybe we want everything to be intuitive,' says Rick Papai, senior project engineer for Dwyer Instruments (Michigan City, Ind.).
'There's hardly a flowmeter we make that can't be configured and supplied in a version with communication capability. But for a $70 flowmeter, will customers pay another $50 to have it communicate? Usually they will not. In the U.S. people don't say how can I do this better, they say how can I do this better for less,' says Mr. Papai.
GF+Signet's Mr. Cartier says, 'Simple, accurate, and maintenance-free are demands which top the list of flowmeter requirements. Today, engineers need to quickly understand, specify, purchase, and implement the best technology choice to survive in this age of heightened expectations.'
According to Dwyer Instruments' Mr. Papai, cost continues to be a decisive factor.
'For instance, most Coriolis and ultrasonic flowmeters start in the $2,000 range, and that's fine for lab environments,' says Papai. 'But most of our customers, even in the semiconductor industry, are looking at the bottom line. To meet cost and price concerns, flowmeters need to satisfy the requirements of multiple applications in more than one industry,' he adds.
Gary Anderson, product manager, Yokogawa Corp. of America (Newnan, Ga.) says, 'Any manufacturer worries about the potential for 'hydraulic noise' in pipes and struggles to come up with a means and electronics to rectify the problem. Users are also looking for more diagnostics in the process, more than just self-checking, they want to know what's happening in the pipes- 'Do I have bubbles in the liquid or cavitation?' Users want signaling in two to three processes,' says Mr. Anderson.
So why the concern about measurement? The competitive environment demands accurate, cost-effective flow measurement.
For more information on flowmeters, visit www.controleng.com/freeinfo . For a broader listing of flowmeter manufacturers, go to the Control Engineering Buyer's Guide at www.controleng.com/ buyersguide .
Easy set up, less pipeline vibes
Newnan, Ga .- DigitalYewFlo flowmeter incorporates a new amplifier featuring Yokogawa's proprietary spectral signal processing technique to analyze the vortex waveform into its spectral components to filter noise from a signal for stable measurement. DigitalYewFlo will provide vibration immunity for accurate measurements at low flows without need for start-up tuning. It also offers accuracy to www.yca.com
Yokogawa Corp. of America
Hatfield, Pa .-Quantim, a Coriolis-based flow controller, provides multivariable output for measuring temperature, flow, and density. The device offers precision, immunity to process conditions, and application flexibility. Quantim measures direct or actual mass, rather than inferred, so no calibrations are necessary. It delivers fluid accuracy of more than 0.5% and the flow path eliminates measurement error caused by clogging, thereby reducing unnecessary downtime and maintenance. www.quantim.com
Two-wire economy, four-wire performance
Greenwood, Ind .-Proline generation of Promags from Endress+Hauser includes the Promag 23 that offers four-wire performance with two-wire economy. The 4-20 mA, loop-powered magmeter is said to generate cost savings through reduced installation, simplified hazardous area protection, and lower energy costs. In addition to a high level of signal output flexibility, new configuration and service software offers individual support, from facility planning to operation and maintenance. Promag 23's two-wire transmitter uses a continuous intelligent-power management system to distribute power. Microprocessor-controlled energy management function allows continuous measurement independent of the flow velocity. www.endress.com
Easy-to-clean, ultra-pure applications
Michigan City, Ind .-The Series UV Polysulfone flowmeter, a highly corrosion-resistant instrument, monitors numerous ultra-pure applications, such as food processing, medical equipment, and reverse osmosis water systems or many corrosive applications. Its high accuracy of 2% is achieved by a float design that allows a 6-in. scale to be incorporated in a 12-in. body for greater resolution. The design is said to be the first to offer an ultra-pure range from 0.5 to 20 gpm. The first three models in the dual-scaled series cover flow ranges of 0.5-5 gpm, 1.0 to 10.0 gpm, and 2-20 gpm. www.dwyer-inst.com
Dwyer Instruments Inc.
Flowmeters communicate digitally
Foxboro, Mass .-I/A Series Model 83 Intelligent Vortex, a family of high-performance flowmeters, include flanged and wafer-body versions and FOUNDATION fieldbus digital communications. Flowmeters have low flow-rate characteristics, wide rangeability, online diagnostics, and can be reconfigured remotely by the host software or with local pushbuttons. A range of materials, communication protocols and options are available to meet the needs of all installations. www.foxboro.com
Vortex flow sensors family
El Monte, Calif .-GF+Signet expands its line of vortex flow sensors to include 3-in. and 4-in. PVDF and HP PVDG Material. Using ultrasonic pick-up technology means these sensors are immune to piping vibrations and have a turndown ratio of 20:1. Sensors are made with PVC, PP, or PVDF material to accommodate applications ranging from chemical delivery to deionized water distribution. Other features include: minimum flow rates down to 0.66 ft/sec are now possible for low flow application; sensors have no moving parts, which eliminate wear and particle shedding; and the sensor works with liquids that are opaque, turbid, nonconductive, or high in conductivity. www.gfsignet.com .
Flowmeters for pneumatic systems
Racine, Wis .-Hedland's direct-reading flowmeters in brass or aluminum construction have a pressure rating of 1,000 psi; in stainless steel, 1,500 psi. All flowmeters used for pneumatic operations have a 10:1 safety factor. Compressed air/gas flowmeters are used to verify air and/or gas compressors are delivering the proper ratings for applications such as pneumatically driven hand tools, actuated cylinders, driven high-speed production or packaging machinery, ejected components from plastic injection molding machines, air driven palletizers, and snow making equipment. Flowmeters have accuracy of www.hedland.com
Hot-tapped insertion magnetic flowmeter
Kenosha, Wis .-YD20-A magnetic flowmeter uses advanced magnetic-flow measurement technology and features venturi-notched tip design. The tip design provides increased accuracy and stability, eliminating errors due to cross- and rotational-flows, common in large pipes. Designed for permanent installation in full-pipe liquid systems, the hot-tapped probe can be installed and retracted from service without interrupting the process stream. Other features include: bidirectional flow measurement; optically isolated input-output buses, field replaceable duplex communication I/O modules; and four-line backlit alphanumeric display. www.flocat.com
Microwave-based flow detector
Minneapolis, Minn .-DTR 131, a noncontact, noninvasive, microwave-based flow detector, optimizes use of machinery and energy by switching process equipment on or off as required. It is a method of monitoring solids flow/no flow in pipelines, ducts, and air slides, as well as at transfer points of vibrating chutes, conveyor belts, and bucket elevators. DTR 131 sensor has no moving mechanical parts, which eliminates wear of the sensor and makes the instrument maintenance trouble-free. It also offers a 5-ft sensing range. www.ramseytsr.com