Topic: Flowmeter Technology Library

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This nifty resource helps you find anything and everything you need to know about flowmeters without having to endlessly surf the web. It provides descriptions and general information for all flowmeter technologies used in process control and automation applications, and allows you to view online intelligence reports, white papers, articles, and technical book abstracts on all things related to flow and the flowmeter instruments that control and measure it.

Flowmeters measure, monitor, regulate and control the flow of industrial gases and fluids. Flowmeters also measure other parameters of liquids and gases commonly used in the process controls and instrumentation industries and are typically chosen based upon the nature of the fluid being calibrated. Considerations for flowmeter selection include viscosity of the liquid, operating pressure, temperature, and flow rate, all of which must be measured in advance.

A flowmeter is a device that meters movement of fluid in a conduit or an open space. This fluid could be water, chemicals, air, gas, steam or solids. Some of the most common types of flow meters include Coriolis, magnetic, ultrasonic, vortex, turbine and multiphase. Flowmeters are made of several basic technologies. Each type has a niche but can generally be used for other applications as well.

Types of Flowmeters

Coriolis Flowmeters are twisting meters that are used to measure mass flow as opposed to volumetric flow. These meters are known for their accurate readings however their size is limiting.

Magnetic Flowmeters are generally used for water applications. They are limited to conductive fluids and they operate on a voltage generator.

Mass Flowmeters are designed for use in gas flows where pressure and temperature are variable. They measure flow rate in terms of the mass of the fluid substance and have units such as lbs/min.

Mass Gas Flowmeters are less affected by density, pressure, and fluid viscosity. They use differential pressure transducers and temperature sensors.

Multiphase Flowmeters are advanced types of flowmeters which accurately measure the flow rates of oil, gas, and water. These flowmeters don’t have any moving parts and cause no separation or mixing.

Positive Displacement Flowmeters are used to measure the flow rate of fluids in areas where straight piping is not possible.

Turbine Flowmeters are mainly used for both liquids and gas. They operate best for applications that have steady, high-speed flows.

Ultrasonic Flowmeters are effective for measuring natural gasses. These meters are non-intrusive and they have no pressure drop. It is important that ultrasonic flowmeters work on clean fluids.

Ultrasonic Doppler Flowmeters are used in slurries and wastewater applications. They use the Doppler effect principle to measure the flow rate.

Variable Area Flowmeters, more commonly known as Rotameters, are used to measure the linear flow of gases and clean liquids.

Velocity Flowmeters and flow sensors measure flow rate in terms of how quickly the gas or liquid is moving. Velocity meters use units like ft/sec.

Volumetric Flowmeters measure flow rate in terms of the quantity of material that is flowing and use units like mL/min.

Vortex Flowmeters are mainly used as an alternative to differential pressure flowmeters. These meters work best with clean, low-viscosity, medium to high speed fluids.

Vortex Shedding Flowmeters are suitable for water flow and coolant flow. They are not mechanical meters like positive displacement or turbine meters and do not hang up.

Flowmeter Research Library

An Introduction to Flowmeters
An educational resource for students, industrial technicians and buyers that are either new to flowmeters or who have some general background knowledge about them but wish to have a broader understanding of flowmeters.

Search related terms for flowmeters
Search with these words combined with flow meter to find alternate paths of research.

Search flowmeter specifications by product category
GlobalSpec offers a variety of flowmeters for engineers. Use SpecSearch to search for the exact flowmeter specifications needed.

Search industry links related to flowmeters
This directory provides links to associations and organizations, consultants and specialists, glossaries and reference tools, regulatory agencies and standards committees, and other industry sources.

Submit Articles on Flowmeter Technologies
CONTROL welcomes contributions from process automation professionals and controls engineers on anything to do with flowmeters that will help educate others.

Featured White Paper Using a Coriolis flowmeter’s multivariable characteristics to validate calibration stability This document describes a procedure that uses the multivarialbe capabilities of a flowmeter to provide an in-situ validation of flow calibration stability.

 

White Papers: In Depth Research

Flowmeters: Discussion of Flowmeter Accuracy Specifications
Author: Siemens
Posted: 01/25/2010
Understanding the accuracy of a given flowmeter is an important field but it can also be misleading as different specifications are used to explain how accurate a flowmeter measurement actually measures. This paper discusses the different specifications and interprets the impact of them.

Why deal with accuracy?

The reasons for dealing with flowmeter accuracy specifications are many-folded. One important reason is from an economical point of view. The more accurate a flowmeter can measure, the more money you will save as the medium is measured with only very little inaccurately.

E.g. If the medium is expensive such as oil, it is important to know exactly how much is consumed. This ensures it is being consumed as efficiently as possible. Another reason is in terms of dosing, where a given amount of a medium is added. This must be done with a high level of precision and the accuracy is thus important in order to dose correctly. This is critical in certain industries such as in pharma or chemical.

Electromagnetic Flowmeters: Lining Material for Water Applications
Author: Siemens
Posted: 01/25/2010

This paper gives an overview of some basic criteria for choosing lining material for the water / wastewater industry and furthermore provides a short description of the properties, strengths and weaknesses of EPDM, NBR, PUR and Ebonite, i.e. the four types of lining material most commonly used in the water / wastewater industry.

Basic criteria for choosing lining material

Due to the functionality of the flowmeter, a non-conductive lining material is imperative, but other requirements vary according to the specific features of the intended application.

Measuring Tube Construction Affects the Long-Term Stability of Magnetic Flowmeters
Author: Dipl.-Ing. F. Hofmann and Dipl.-Ing. B. Schumacher, KROHNE Messtechnik GmbH Co KG Duisburg, Germany
Posted: 07/29/2009
Electromagnetic flowmeters, also known as mag meters, are popular and proven devices for flow measurement of electrically conductive process fluids and for volumetric filling machine applications. Of prime importance to a mag meter’s accuracy and long term performance is the condition of the metering section of the flow sensor.

Unlike in most processes, mag meters in filling machine applications are frequently subject to widely varying conditions during normal operation. As a result, they are viable candidates for evaluating their long term performance in an accelerated use environment. Therefore PTB, a German research and approvals agency, in association with KROHNE, undertook an extensive project to study the long term measurement stability of mag meters in filling machine applications.

Faraday's law is the basis of a mag meter’s measuring principle. The design generally features an electrical isolating liner on the inner wall of the mag meter measuring tube. Linings such as PTFE, PFA or polypropylene or for hygienic reasons, PFA (perfluoroalkoxy) are used. Pressure bearing ceramic pipes are also used. PFA is known to absorb moisture, it can flow under pressure and temperature which means that it changes structure and shape which, in turn, affects the interior diameter of the measuring tube. Changes in the inner diameter of the measuring tube lead to measurement errors. This can lead to problems, especially when extreme precision or repeatability are at stake. This only takes effect after the devices have been in use for longer periods of time and through the corresponding frequent cleaning processes using liquid or steam as are common in the food industry.

The effect is particularly significant when it comes to mag meters used on filling machines for filling PET bottles ("Filling mag meter"). In this case, an extremely high degree of repeatability is required and the quality of the filling process is directly visible in each individual bottle.

That is why, in a joint research cooperative with the Physikalisch-Technischen Bundesanstalt (National Metrology Institute) (PTB), KROHNE Messtechnik tested the measurement stability of filling mag meters. Filling mag meters with PFA liners and filling mag meters with ceramic measuring tubes were both tested. The PTB was interested in this test because for more than 20 years Magmeters with ceramic measuring tubes have been the norm in the normal PTB measuring systems as well as in many other calibration test stations. Thanks to this test, the PTB was able to gain additional knowledge about the behavior of these devices under difficult conditions.

Measuring Tube Construction Affects the Long–Term Stability of Magnetic Flow Meters
Author: Dipl.-Ing. F. Hofmann and Dipl.-Ing. B. Schumacher, Krohne Messtechnik GmbH Co KG Duisburg, Germany
Posted: 03/24/2009
Electromagnetic flowmeters, also known as mag meters, are popular and proven devices for flow measurement of electrically conductive process fluids and for volumetric filling machine applications. Of prime importance to a mag meter’s accuracy and long term performance is the condition of the metering section of the flow sensor.

Unlike in most processes, mag meters in filling machine applications are frequently subject to widely varying conditions during normal operation. As a result, they are viable candidates for evaluating their long term performance in an accelerated use environment. Therefore PTB, a German research and approvals agency, in association with KROHNE, undertook an extensive project to study the long term measurement stability of mag meters in filling machine applications.

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