Potato Grower

December 2019

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WWW.POTATOGROWER.COM 15 offer a five-year battery life, and battery replacement cost is a small fraction of the cost associated with a typical mechanical meter repair. ELECTROMAGNETIC OR MECHANICAL? • Electromagnetic flow meters—also called magnetic meters, or "magmeters" for short— operate by Faraday's Law: If a conductive fluid, such as irrigation water, goes through a magnetic field, it creates a small voltage. Motion of a conductive fluid through the field generates a small amount of electricity, just like a generator (more flow = more voltage). Electrical coils placed outside the flow are momentarily energized. A magnetic field crosses the flow at right angles, electrodes measure the changing voltage, and the display unit shows rate and total. In the past 15 years or so, magnetic meter technology has advanced so much that some are now available battery-powered, making them great for irrigation use. To ensure you get the best value for your money, consider what you need in the flow meter—add for pulse output, straightening vanes (for tight space installations), high-capacity bearing assembly, digital readout, data-logging and any other options you may need on the mechanical propeller meter—then compare the price to a battery-powered electromagnetic meter that normally includes all the options you need as standard features. In the end, magmeters offer higher accuracy over broader flow ranges, no moving parts to replace, durability, no flow obstruction, long battery life, low maintenance, longer warranties and minimal straight run requirements for tight space installations. • Mechanical propeller meters— sometimes called prop meters—consist of a rotating device, typically a helical- shaped impeller, positioned in the flow stream. The impeller's rotational velocity is directly proportional to the velocity of the flow. As water flows through the pipe, it spins the propeller. The spinning motion is then carried to the head of the meter, through either gears or a drive cable. The instantaneous flow rate and total volume flowed can be read on the mechanical or digital meter register. Though they operate under the same principle, these meters are available in a variety of installation configurations to suit the installer's need: saddle style, flanged style, threaded ends, grooved ends, etc., which can make installation simpler. Propeller meters can offer an economical flow metering solution when all that's needed is mechanical rate and total volume flowed. They typically work fine in clean water applications, but water carrying debris can damage the moving parts. While mechanical propeller meters used to be the most economical choice for irrigation, that's typically no longer the case. Many times, choosing a mechanical propeller meter is much like ordering your meal from the à la carte menu at a restaurant: If all you want is one taco and a glass of water, you will get a low-cost meal. But, add rice, beans, guacamole and sour cream, and you will likely pay more ordering from the à la carte menu than purchasing a combination plate that includes all the options you want. If you need anything other than mechanical rate and total, comparing the cost and benefits of mechanical technology to electromagnetic may be wise. Why Milestone? y Milestone? 1. 1. Over 50 years of hard earned Over 50 years of hard earned Over 50 years of hard earned experience! 2. experience experience 2. 2. Custom designed to fit your Custom designed to fit your Custom designed to fit your operation! 3. operation! operation! 3. 3. Attention to detail! 4. 4. 4. Knowledgeable and competent Knowledgeable and support! 395 W Hwy 39, Blackfoot ID Phone: 208-785-4285, Toll Free: 800-574-1852 Fax: 208-785-1060 info@milestone-equipment.com www.milestone-equipment.com Sizers/Eliminators/Sorters Owned and Manufactured in the U.S.A 2358-11Milestone12h.indd 1 4/19/19 2:43 PM

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