The Operating Principles of a Magnetic Flowmeter

Below is a video, courtesy of Badger Meter, illustrating the operating principles of magnetic flowmeters (also known as magmeters).

A magnetic field is applied to the flow tube, resulting in an EMF proportional to the flow velocity passing perpendicular to the magnetic flux lines. The physical principle at work is Faraday's law of electromagnetic induction.

Magnetic flow meter requires a conductive fluid, and electrically insulated internal pipe surfaces to operate.

Advantages:

• Low maintenance cost
• No moving parts
• Good for slurry
• Good for corrosive fluids
• Very linear
• Minimal flow restriction

Disadvantages:

• Requires electrically conductive fluids

For more information on magmeters, visit TECO at http://www.teco-inc.com of call 800-528-8997.

Variable Area Flowmeters (Rotameters)

ABB Rotameter

Variable area flowmeters (rotameters) are the most cost effective solution for almost all applications involving the measurement of industrial process liquids, gases or steam.

They meet the application requirements by featuring a wide range of design varieties and sizes. Technology proven, they offer a long life and high reproducibility. Variable area flowmeters are excellent mechanical back-up meters because no external power supply is needed.

TECO was the first firm to represent and sell the Fischer & Porter Rotameter Line, dating back to March, 1947.  With over 70 years of ABB Rotameter history, TECO is your best source to help with your rotameter applications.   http://www.teco-inc.com | 800-528-8997.

Understanding Coriolis Flow Measurement

Coriolis flowmeters directly measure the mass flow of a subject fluid, which is inclusive of regular and supercritical liquids and liquefied gases. Operating on the Coriolis effect principle, Coriolis flowmeters create a controlled condition in which the mass flow of the fluid can be directly measured. They rely on motion mechanics: one or two tubes are aligned inside a Coriolis flowmeter, then made to oscillate with an exciter. Fluid flows through the oscillating tubes, twisting them slightly in proportion to the mass flow of the fluid and its inertia. There are highly reactive sensors attached to the tubes; when the measured substance flows through the vibrating tubes, the numeric difference between sensor readings provide the basis of the resulting fluid is mass flow measurement. This process also delivers a second measurement: the density of the substance. The sensors measure the frequency of oscillations. Coriolis flowmeters rely on direct computation instead of an algorithm, and therefore are regarded as highly accurate instruments in industry, coming in at 0.1 percent accuracy in some cases.

Rotation without mass flow
(image courtesy of Wikipedia).

Rotation with mass flow
(image courtesy of Wikipedia).

Coriolis flowmeters are advantageous choices for many industrial applications. They are used to measure drinking water, oils and gases, chemicals, etc. However, these mass flow measurement products particularly stand out in the chemical industry. As a prerequisite for most fluid processing operations, measurements and quantities often rely upon mass instead of upon volume. Coriolis flowmeters, with their direct measurement of mass flow, can be the optimal choice for applications requiring mass flow measurement.

As beneficial as Coriolis flowmeters are, they are not immune to some engineering and practical limitations. The most recognized limitation is the size of the pipes the meters are able to accommodate. A Coriolis meter is comparatively large, when other measurement instrument technologies are considered, making it difficult to place in some installations. In addition to being recognized as one of the most accurate flow measuring technologies, the Coriolis flowmeter requires little maintenance.

The vibration pattern with mass flow
(image courtesy of Wikipedia).

The vibration pattern during no-flow
(image courtesy of Wikipedia).

Selecting and configuring the instrument properly and assuring that installation is performed in accordance with manufacturer instructions are necessary tasks to achieving best instrument performance. Reach out to an instrumentation specialist with your flow measurement challenges, combining your process knowledge with their product application expertise to develop effective solutions.

For additional information on any industrial flow measuring technologies visit Thompson Equipment (TECO) at  http://www.teco-inc.com or call 800-528-8997.

An Introduction to Ultrasonic Flow Technology

How Ultrasonic energy
is used to measure flow.

Ultrasonic energy flow meters measure, via sound waves, the velocity of liquid flowing through a pipe––however, this pipe includes not just the traditional “pipe” but also mass flow chutes or something with open channels, free surfaces.

There are three different types of ultrasonic energy measuring tools, called flow meters: the first is the Open Channel flow meter which receives its calculations by computing geometrical distance; the second is the Doppler shift flow meter which reflects ultrasonic beams off sonically reflective materials, e.g. air bubbles; the third is the contrapropogating transit-time flow meter or, more recognizably, the transmission flow meter. The transmission flow meter has two versions: the in-line and the clamp-on. The former is “intrusive” whereas the latter is not, an outward device. These 72+ inch tools, using ultrasound technology, have the ability to measure fluids in bulk, all with distinct properties and principles., The use of this technology is most used in the respective oil and nuclear industries, wastewater technologies, pharmaceutical applications, and the food and beverage industry.

For intrusive flow meters, sensors are fitted opposite one another and alternate bouncing ultrasonic signals back and forth in the pipe, in an almost tennis-like format. In an elementary explanation, by increasing the number of sensors, engineers are able to decipher flow proportions through calculations of velocity between sensory transmissions; thereby, the flow volume can be computed.

For unintrusive flow meters, a literal clamp-on flow meter is placed atop the pipe so as not to interrupt flow. One of the most special properties uninstrusive flow meters offer is the ability to bounce ultrasonic sensors through piping up to four meters in diameter; this makes seemingly impossible feats possible, especially in otherwise difficult fields, e.g. hydroelectric.

Although the technology is pervasive, there are disadvantages still as there are advantages. However, the majority of the equipment’s disadvantages are unavoidable, such as costs and apparatus sensitivities. Nonetheless, there is also the threat of low ultrasonic accuracy, or attenuation, dependent on what systems are used and under what circumstances and command. Alternatively, one of the most publicized advantages is that ultrasonic energy flow technology is used for custody transfer of natural gases and petroleum liquids. Custody transfer usually entails following industry, national, and government standards and regulations. Ultrasonic energy flowmeters and analyzers are also relatively low maintenance, e.g. self-diagnosing. The technology has the capability to control and manage high pressures as well as high temperatures, and, being a popular application among engineers, manufacturers and the like, is reliable in its performance and consistency.

For more information on any industrial flow application, contact TECO at 800-528-8997 or visit www.teco-inc.com.