Accuracy is boosted with new flowmeter design

Flow Measurement & Control

October 2002 Flow Measurement & Control

The MAG 5100 W series of low-cost flowmeters meets the requirement for improved accuracy at decreasing flow rates with a number of innovative design features. Foremost among these is the patented composite elastomer liner with a cross-linked structure that provides the meters with a high resistance to chemicals and hydrocarbons found in potable and waste water.

The new range of MAGFLO electromagnetic flowmeters, MAG 5100 W, provides improved accuracy at decreasing flow rates and is suitable for both potable and waste water

Soft elastomer is used to line the coned sections and the flange gasket face, providing high abrasion resistance at the inlet and outlet of the flowmeter. This also lowers the risk of damaging the flowmeter when installing it and eliminates the need for additional gaskets.

The design utilises hard elastomer to line the measuring part of the flowmeter, providing dimensional stability against the effects of pressure and water absorption. This distinguishes this patented elastomer from the widely used soft elastomers, which show a slow drift by absorbing water. This is particularly noticeable in smaller sizes, which can absorb water to an extent that the internal diameter is altered, causing a reduction in accuracy. In contrast, the liner of the MAG 5100 W maintains its performance throughout the service life of a sensor regardless of the pressure or temperature.

The cone-shaped design of the sensor increases the velocity of the water passing through the measuring section, while simultaneously straightening the velocity of the profile. This optimises the flowmeter for decreasing flow rates and low-flow situations. "Previous pitfalls of coning, such as increased pressure drop, cavitation and swirl have been successfully eliminated by optimising the shape and angle of the MAG 5100 W cone," says Mick Baugh, Danfoss business unit manager, Motion Control and Flow.

By maintaining the face-to-face length of meters according to ISO 13359, the MAG 5100 W series is interchangeable with existing flowmeters. This allows for cost savings, while negating the need to downsize the line when flow velocities have fallen to a level where accuracy is impaired. "The accuracy of the new series can be further extended by combining it with the MAG 6000 signal converter. This marks Danfoss's first water industry dedicated 0,25% accurate flowmeter, making it ideal for water leak detection," says Baugh.

The new design has also allowed the use of a powder coating finish to the meter, that is superior to the traditional wet paint in both appearance and corrosion protection. The absence of outer coil housing covers has also resulted in a slimmer design, enabling easier installation.

The MAG 5100 W flowmeter range is available in sizes ranging from DN 25 to DN 1200. However, since nearly 80% of all flowmeters sold are within DN 50-300, Danfoss has primarily focused its innovative efforts within this range, thereby meeting the predominant demands of the industry.

The range of flowmeters is also compatible with the Danfoss Verificator, thereby fulfilling the objectives of the DCA (Danfoss Continuous Accuracy) programme for MAGFLO electromagnetic flowmeters. "The MAGFLO Verificator detected all set-up faults in the complete flowmeter, is straightforward to use, and is sturdy and suitable for field use," assures the WRC (Water Research Centre), an independent research, technology and consultancy company in the UK, after conducting a test on the product.

For more information contact Mick Baugh, Danfoss, 011 803 8390, [email protected]

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Flow Measurement & Control

Accuracy is boosted with new flowmeter design

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