Using Flowmeters

Beyond just manufacturing and process control, are flowmeters saving technology-based civilization as we know it? In the book, “Flushed: How the Plumber Saved Civilization,” W. Hodding Carter explains in detail the water supply system constructed to supply Rome. “The Empire could tap water 50 miles away, bring it to the city, and then just let it keep on flowing.

By Dick Johnson, CONTROL ENGINEERING June 1, 2007

Beyond just manufacturing and process control, are flowmeters saving technology-based civilization as we know it? In the book, “Flushed: How the Plumber Saved Civilization,” W. Hodding Carter explains in detail the water supply system constructed to supply Rome. “The Empire could tap water 50 miles away, bring it to the city, and then just let it keep on flowing. The Romans didn’t bother with reservoirs or any type of system that allowed water to be preserved. They simply let it flow—in some cases for thousands of years; a few such aqueducts are in service today.”

Workable back then, such systems are hardly practical in the modern world. The days of leaving the tap run are over. Technology has developed flowmeters to measure water use, ensuring an accurate accounting of the volume used. A water distribution and treatment infrastructure needs to be maintained and paid for, and a water meter alerts the user to any improper or wasteful use of this dwindling and costly resource.

Most survey respondents who specified and bought flowmeters did so for in-plant use(66%), with continuous processing accounting for the largest number (42%) of applications.

Flowmeters handle many substances in a variety of applications beyond water flow, as respondents confirmed in the latest on-line survey conducted by Control Engineering and Reed Research Group. Asked to respond to questions about flowmeter technology choices and feature preferences in their own words, subscribers indicated that application adaptability, accuracy, repeatability, and the lowest installed cost are essentially what they want.

Among survey respondents that buy or specify flowmeters, a majority (66%) did so for in-plant use. Of the remainder, 21% used them for OEM resale applications and 13% for both OEM and in-plant requirements. Continuous processing, at 42%, was the primary application. Batch processing accounted for 28% of the total and utility services for 23%. Applications not falling into any of these categories came in a 7%. Totals were similar to those in the last survey, covered in a June 2005 article.

Results in 2007 also showed most flowmeters (more than 90%) are used in full-flow pipe applications. Open channel or partial flow pipe and other flow applications accounted for the small portion remaining.

Technology battle

With a variety of technologies to chose from (18 categories were offered in the survey), respondents changed device preferences since 2005. Turbine (44%) and magnetic flowmeters moved to the top of the list. Orifice flowmeters, which tied with magnetic types for first place in 2005 and alone held the top spot in 2001, dropped to third, bowing to newer technologies. In another significant change, Coriolis flowmeters, in fifth place in 2001, dropped to seventh place this year.

Those who added comments to their survey indicated that Coriolis meters are still the right choice for many applications. Ken Rhodes, director for Cacique Inc., said that accuracy is key in his operation, and that only Coriolis meters give the required information (total weight, specific gravity, temperature, percentage by weight for specific components) for the feedstock his company purchases.

Types of flowmeters used changed in some ways from 2005 to 2007. Turbine (44%) and magnetic flowmeters moved to the top and orifice flowmeters dropped to third as newer technologies gain popularity.

Alice McWilliams, Chevron Phillips’ senior instrument electrical engineer, likes the Coriolis flowmeter’s adaptability and low maintenance and said they are excellent for handling the particle-laden fluids in the company’s applications. “I want to put in a flowmeter and never see it again,” says McWilliams.

Joe Ransaw, engineering specialist for Solutia Inc., counts on the accuracy of Coriolis meters in his process measurement of hydrogen gas flow. Perhaps David Weng, control system engineer at Dey L.P. sums it up best in his terse comment: “Coriolis—accuracy.”

Other factors

Communication protocols used with flowmeters experienced at least one significant change since the previous survey. The familiar 4-20 mA protocol remains most used, but the equally familiar 0-10 V protocol moved from third to second while the HART protocol dropped to third. Others on the list—including Ethernet, Profibus-PA, FOUNDATION fieldbus H1, Interbus, LonWorks, and WorldFIP—remained stable.

Significant flowmeter demand continues. More than a quarter (26%) of all respondents plan to increase flowmeter purchases in the next 12 months; 54% expect to keep spending at current levels. According to the survey, numerous factors can be expected to drive purchasing habits for the foreseeable future. These include (in descending order):

Better reliability;

Greater accuracy;

Ease of calibration;

Low lifecycle cost/low capital cost;

Relaxed installation requirements (fewer process penetrations);

Digital communications capability;

Noninvasive measurement;

Custody transfer accuracy and recording capability; and

Strap-on portability.

These factors were noted by respondents in the written responses when asked to provide an example of why they chose or considered one technology over another. Most said these factors influenced the specification process.

Flowmeter products

Control Engineering subscribers, using a list provided, identified the following as leading suppliers of flowmeters. To find other suppliers, search . To find system integrators with related expertise, go to .

Flowmeter vendors, not prompted in the survey, include:

Dwyer Instruments Inc. ;

Emco Flow ;

Hedland, a Div. of Racine Federated Inc. ;

McCrometer Inc.

Universal Flow Monitors Inc.

Read about their products with this article, June 2007, at .

Multivariable vortex flowmeter

Rosemount MultiVariable 8800 vortex flowmeter from Emerson Process Management incorporates multivariable technology to deliver the benefits of vortex technology and a temperature compensated mass flow output directly from the meter, reducing process variability. Meter features isolated, independent vortex and temperature sensors. Both may be verified or replaced independently without breaking the process seals, eliminating the need for process shutdown for verification of the temperature sensor. Product is said to lower total installed cost of temperature compensated measurement points by 25% over external compensation of a traditional vortex device. Emerson Process Management

Safety certified Coriolis meters

F-Series line of compact Coriolis meters from Micro Motion offere. All line sizes are available with the TÜV-certified Model 2700 transmitter for use in SIL-2 and SIL-3 applications. Compact and drainable, these Coriolis meters are said to fit into tight, existing piping configurations and are unaffected by short or adjacent pipe runs. Micro Motion

In-line ultrasonic flowmeter

FDT100 Series flowmeters from Omega Engineering use advanced transit-time ultrasonic technology in which two flow sensors alternately transmit and receive a signal and “time of flight” is used to measure flow rate. Designed for long, economical service in consumable or industrial water applications, these battery-powered meters have no moving parts. Pressure loss is minimal and filtration is unnecessary. Long-term stability and a wide measurement range facilitate monitoring of consumption and leakage. Two flange styles are available—150-lb ANSI and DIN—in various sizes with a choice of integral or remote electronics that display flow rate or total at the push of a button. Omega Engineering Inc.

Meters for conductive liquids

FSM4000 electromagnetic flowmeter provides the versatility to measure a wide range of flow applications in the pulp/paper and metals and mining industries. It is applicable for measuring conductive liquids and is said to provide quick response and noise free output. Featuring an improved ac magnetic field excitation and digital signal processing, it delivers ABB

Multivariable flowmeter, hygienic

Promass S flowmeter offers multivariable measurement capability said to reduce user metering point costs; enable metering of mass flow, density, and temperature; and perform calculation of volume and temperature compensated concentration. It is said to offer accredited calibration (ISO / IEC 17025), with accuracy of 0.1% overall range. The meter is reportedly easy to install and requires no inlet and outlet runs. Its welded design has no moving parts and internal seals for maintenance-free operation. Endress+Hauser Inc.

Rugged vortex flowmeter

High-performance vortex flowmeters from Foxboro/Invensys are intended for demanding liquid, gas, and steam process applications up to 800line sizes from ¾ to 12 in. for flow rates from 1.20 to 8,560 gpm. Model 84W wafer body is available in line sizes from ¾ to 8 in. for flow rates from 1.20 to 3,610 gpm. Model 84S meets sanitary requirements per specification 28-03 and is available in 2-in. and 3-in. line sizes for flow rates from 5.50 to 648 gpm. Foxboro/Invensys

Clamp-on, wetted flowmeters

Ultrasonic flowmeters from Siemens Energy & Automation include clamp-on and wetted models. Sitrans F US clamp-on ultrasonic flowmeters measure the flow of electrically conductive and non-conductive liquids as well as gas. They offer easy installation, no pressure drop or energy loss, a wide turn-down ratio, no need to cut the pipe or stop the flow, and minimal maintenance. They are intended for non-contact operation with liquid or gas, in flow survey or temporary installations, and for pipe diameters to 360-in. dia. Sitrans F US wetted ultrasonic flowmeters provide highly accurate measurement of electrically conductive and non-conductive liquids. Sizes are from 2- to 48-in. dia or to 160-in. dia with weld-in retrofit. www.sea.siemens Siemens Energy & Automation Inc.

Straight tube mass flowmeter

Optimass 1000 mass flowmeter from Krohne Inc. is said to be the only sensor in its class with secondary pressure containment as standard. Intended for the petrochemical, water/wastewater, chemical, pharmaceutical, food and beverage, and pulp and paper industries, the device features straight twin measuring tubes for easy draining and cleaning. It also has an optimized divider for minimum pressure loss, modular electronics that are easy to replace, and data redundancy with accurate plug-and-play replacement of electronics. It is suitable for standard applications to 265 Krohne Inc.

Low-flow measurement options

Options for the Brooks Instrument Quantim Coriolis family of low-flow measurement products include a Hastelloy C-22 Coriolis sensing tube for use with corrosive fluids. A high-pressure option can be specified for pipeline pressures to 4,500 psi. Both are available on QMBM (meter) and QMBS (sensor) products. The Hastelloy tube option is available. The high pressure option should be specified for applications with a maximum pressure of 1,500 and 4,500 psi. Brooks Instrument

Vortex flowmeter with built-in reducers

Latest digitalYewflo vortex flowmeter from Yokogawa eliminates the need for costly sections of reducing runs common when applying vortex flowmeters by providing up to two-meter-size stepdowns. For example, if a 1- or 11 to 12 in. Yokogawa Corp.

Metal magmeter: flow sensing, rugged

Signet 2552 metal magmeter from Signet/GF Piping Systems is a rugged insertion flow sensor that permits hot-tap access to the pipe stream. The design has no moving parts to foul and allows quick and easy installation and maintenance without system shutdown. Three output choices are incorporated into a durable metal housing to create a robust device capable of accurate flow sensing in harsh environments. Pipe sizes range from 2- to 48-in. dia. It has a wide dynamic flow range of 0.15 to 33 fps with repeatability of Signet/GF Piping Systems

Self-cleaning mass flowmeter

Model GF90 flowmeter from Fluid Components International has self-cleaning purge ports said to maintain optimum flow measurement performance and reduce maintenance costs in applications with dirt, grit, and grime. Insertion style GF90 mass flowmeter’s self-cleaning purge ports minimize maintenance. By connecting purge ports to compressed air, inert gas, or solvent purge lines, process contaminants can be removed regularly and without removing the flow sensor element from the pipe. It handles fluid temperatures from -100 to 850 Fluid Components International

IS clamp-on ultrasonic flowmeter: wetted

DigitalFlow ISX878 from GE Sensing is a wetted version of the company’s intrinsically safe, clamp-on ultrasonic flowmeter. High accuracy, two-wire flowmeter has power and output signal on the same wires. It is said to be cost-effective with high quality and performance. Its compact design minimizes installation space and retains the benefit of intrinsic safety in a two-wire device. DigitalFlow has no pressure drop, no moving parts, does not wear, and requires no routine maintenance. GE Sensing

Hybrid ultrasonic flowmeter, nonintrusive

Duosonics ultrasonic flowmeter automatically switches between “Pulse Doppler” and Transit Time technologies depending on the fluid conditions in the pipe, such as ultra-pure water, slurries, juice with pulp, or crude oil. It enables accuracy of 0.5% at reading and direct flow profile measurement. The highly accurate and non-intrusive design can handle industrial applications where other meters can fail, such as short straight pipe runs with undeveloped flow or different fluids running through the same pipe. Fuji Electric

Author Information

Dick Johnson is a consulting editor with Control Engineering. Contact him at .