P.I. Process Instrumentation
  • Subscribe
  • Magazine
  • Webinars
  • White Papers
  • Videos
  • 3D Models
  • Events
  • News & Reports
  • Innovation Awards
  • Flowmeters
  • Instrumentation
  • Measurement
  • Monitoring
  • Process Control
  • Topics
    FlowmetersInstrumentationMeasurementMonitoringProcess Control
    Resources
    MagazineWebinarsWhite PapersVideosEventsNews & ReportsInnovation Awards
    User Tools
    SubscribeAdvertiseAbout UsContact UsPrivacy PolicyTerms & Conditions
    https://www.facebook.com/PIprocessinstrumentation/
    https://www.linkedin.com/showcase/11107902
    https://twitter.com/pi_processinst
    1. Instrumentation & Measurement
    2. Flow Measurement

    Variable Area Flowmeter Accuracy Statements

    July 27, 2012

    David W. Spitzer Variable area flowmeters tend to have their accuracy statements expressed as a percentage of:? A. Actual flow B. Full-scale flow C. Meter

    David W. Spitzer
    Spitzer Headshot
    Spitzer Headshot
    David W. Spitzer

    Variable area flowmeters tend to have their accuracy statements expressed as a percentage of:?

    A. Actual flow
    B. Full-scale flow
    C. Meter capacity
    D. Calibrated span

    Commentary
    Flowmeters that have an accuracy statement expressed as a percentage of actual flow usually have a well-defined output at zero flow. For example, with no flow, vortex shedders do not shed vortices, positive-displacement flowmeters do not rotate, and differential-pressure flowmeters exhibit zero pressure differential. All of these are well-defined conditions. This is not the case with variable area flowmeters where the float may fall, but it will not necessarily be at a well-defined position.

    In addition, the float can stick during operation (and especially at low flow), causing measurement errors that would exceed a reasonable percentage of actual flow. Answer A is not correct.

    The accuracy of variable area flowmeters is typically specified as a percentage of full-scale flow, so Answer B is correct. For variable area flowmeters, meter capacity is the same as the full-scale flow, so Answer C is also correct. Answer D could be correct if the variable area flowmeter is calibrated at full-scale flow.

    Additional Complicating Factors
    The percentage of full-scale statement could also be expressed as an absolute flow error (such as +/-1 liter per minute) by multiplying the full-scale accuracy statement by the full-scale flow.

    David W. Spitzer is a regular contributor to Flow Control magazine and a principal in Spitzer and Boyes, LLC offering engineering, seminars, strategic, marketing consulting, distribution consulting and expert witness services for manufacturing and automation companies. He has more than 35 years of experience and has written over 10 books and 250 articles about flow measurement, instrumentation and process control.

    Mr. Spitzer can be reached at 845 623-1830 or www.spitzerandboyes.com. Click on the “Products” tab in the navigation menu to find his “Consumer Guides” to various flow and level measurement technologies.

    Continue Reading

    HAWK launches new fiber optic sensing website

    Quiz Corner: The most common variable speed drive configuration is…

    Sponsored Recommendations

    Pharmaceutical Process Manufacturing and Utilities Solutions for Life Sciences

    4 Key Challenges Facing Life Sciences Manufacturers

    Overcome Measurement Challenges in Life Sciences

    Biotech Facility Case Study

    Latest in Flow Measurement

    Shutterstock 222781177 (1)
    Sponsored Content
    White Papers

    ASK THE EXPERT: Guided Wave Radar Technology Gives Precise, Cost-Saving Measurements for Industrial-Level Measurement Applications

    Sept. 29, 2023
    Maxresdefault 633367404c280
    Sponsored Content
    Instrumentation & Measurement

    Learn More About Our Engineering Tools: Increase Efficiency through MyEmerson’s Digital Tools

    Sept. 28, 2022

    Most Read

    New Flow Research study finds thermal flowmeters capitalize on growth in gas flow measurement

    Measuring flow without a flowmeter

    The key role of variable area flowmeters in offshore drilling

    Sponsored

    Wireless Tailings Dam Monitoring Systems

    MANAGING RISK. REDUCING UNCERTAINTY.

    Clean-in-Place Solutions for Life Sciences

    P.I. Process Instrumentation
    https://www.facebook.com/PIprocessinstrumentation/
    https://www.linkedin.com/showcase/11107902
    https://twitter.com/pi_processinst
    • About Us
    • Contact Us
    • Advertise
    • Do Not Sell or Share
    • Privacy Policy
    • Terms & Conditions
    © 2023 Endeavor Business Media, LLC. All rights reserved.
    Endeavor Business Media Logo