Ask The Experts...

Focus on Flowmeter Selection for Water & Wastewater Industries

How do you choose the best flowmeter for your particular water or wastewater application? With so much information out there and so many factors to consider, the task is a daunting one for flow system designers. In a series of articles over the next three months, we help you focus on the most important aspects of flowmeter selection.

The first step is to know the relative strengths and weaknesses of the two main categories of meters: those with measuring devices located in the process stream and those which do not impede the flow path. Common examples, considered the most appropriate for water and wastewater applications, are propeller meters and magnetic flow meters.

The propeller meter is one of the most durable mechanical meters on the market and is relatively low cost. Its only moving part is the propeller and it provides both rate-of-flow and total flow without the need for electrical power. The magmeter is non-obtrusive, using electromagnetic fields generated across the meter's flow tube to measure flow. If the flow contains a lot of debris or sludge, such as applications in wastewater treatment facilities and industrial effluent, the magmeter offers the best solution.

Once the type of flowmeter is chosen, the designer must now consider the level of accuracy required by the application. He/she has to determine the minimum acceptable system accuracy, to avoid paying a high price for unnecessarily precise meters. For example, in a production environment, an accuracy of +/-2% may be fine, but for water sales, a range of +/-1.5% may be mandatory. As a guide, the accuracy of a propeller meter is typically +/-2% of rate, whereas the accuracy of a magnetic meter is +/-0.5% of rate.

Next month, we will look at how factors such as flow rate and fluid characteristics affect flowmeter selection. If you have any questions in the meantime, please contact your nearest McCrometer flowmeter expert at 951-652-6811 or visit our web-site for a free flow evaluation www.mccrometer.com.

NEWS: McCrometer acquires flowmeter manufacturer, Water Specialties. Viewed as a positive step by both parties, the acquisition combines the talents, experience and product lines of the two companies, creating a major supplier of advanced flow measurement technology to the water and wastewater markets.

"We are very excited and optimistic about this acquisition," said McCrometer President Kerry McCall. "McCrometer's expertise lies in developing, manufacturing and distributing flow measurement solutions. By combining these strengths with Water Specialties' products and industry experience, we are creating a premier provider of flow measurement solutions to the water and wastewater markets."

*******************************************
Copyright 2000 McCrometer

*******************************************