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Four Keys for Selecting an Irrigation Flow Meter Part 2 Adapted from Information by Katie Englin, Agricultural Irrigation Specialist, Seametrics Picking up where we left off . . . \ Determine if a signal output is necessary. Some applications require the meter to send a signal, such as pulse, 4-20mA, or Modbus. In some cases, the output is used to send a signal to a remote telemetry system, allowing irrigators to collect meter data remotely. Signal outputs are optional on propeller flow meters and typically require adding the cost of a transmitter or special digital register to provide outputs. Most electromagnetic flow meters include a pulse signal output as a standard feature, making them “telemetry system ready,” and Modbus or 4-20mA output signals can be provided for a small addi- tional cost. \ Know how much room is available to install a meter. Straight-run pipe requirements for flow meter installations are expen- sive in terms of materials and labor. When adding a new flow meter to existing equipment, there may not be enough space to accommodate the straight pipe run necessary for accurate flow measurement. Mechanical propeller meters re- quire more space to install due to the longer straight run requirements to ensure proper and accurate performance. Straight- ening vanes or flow straightening devices can be installed ahead of a propeller meter to shorten the straight-run pipe requirement, but can add substantially to the cost and installation labor involved. Typically, a standard full-bore electro- magnetic flow meter will fit nicely into a tight space and measure flow accurately. Even some insertion style magnetic flow meters will require less straight-run installation space than a propeller meter, and operate accurately. 2. How important is accuracy? In general, electromagnetic meters are more accurate than mechanical meters. Most elec- tromagnetic meters for irrigation offer +/-1% of flow rate over a wide flow range with no head loss. The most common mechanical meters used in irrigation are propeller flow meters, with +/-2% accuracy within a specified flow range, and some head loss. Since there are no moving parts to wear out, electromagnetic meters can maintain accuracy over the lifetime of the meter. 3. What is the meter maintenance schedule? Like most equipment, irrigation flow meters will need attention at some point. Mechanical propeller meters have moving parts - such as the propeller, bearings, and mechanical register that can wear out. Parts of mechanical meters have increased substantially over the years, and repairing one can be almost as costly as replacing it. The standard warranty on most mechanical propeller meters is one year. Electromagnetic meters do not have any moving parts to break, and maintenance is usually limited to battery replacement. Many battery-powered magnetic flow meters now offer a five-year battery life, and battery replacement cost is a small fraction of the cost associated with a typical mechanical meter repair. In addition, most electromagnetic flow meters come standard with a two- to five-year warranty, depending on brand. ~Stay tuned. We’ll cover tip number 4 next, in Part 3 . Nitrate Coated Premium Liners 5x6, 5x8, & 5x10 Gardner Denver 5-1/2x8 & 5-1/2x10 Gardner Denver 7-1/2x8 & 7-1/2x10 Gardner Denver Rods Heat-Treated & Chromed 5x6, 5x8, & 5-1/2x8 Gardner Denver 5x10 & 5-1/2x10 Gardner Denver 7-1/2x8 & 7-1/2x10 Gardner Denver New Pumps In Stock Gardner Denver 4x5 TEE Triplex. Gardner Denver 5-1/2x5 TEE Triplex Gardner Denver 4x5 or 4-1/2x5 Duplex Gardner Denver 5x6 Duplex Gardner Denver 5x6 Air Drive Duplex Gardner Denver 5x8 Duplex Gardner Denver 5-1/2x8 Duplex Gardner Denver 7-1/2x8 Duplex Gardner Denver 7-1/2x10 Duplex Gardner Denver 5-1/2x5 THE Triplex Gardner Denver 5x8 PAH Triplex Call for Prices. We Have a Variety of Brands of Mud Pump Parts and Power Units in Stock. Special or Obsolete Parts Made to Order . Cash for Surplus Mud Pumps . Rebuilt Mud Pumps 4-1/2x6 Gaso Duplex 4-1/2x6 Oilwell Duplex Gardner Denver 4-1/2x8 PA-8 Triplex Gardner Denver 5x6 Duplex Gardner Denver 5x10 Duplex Gaso 5x10 Duplex OVER 300 PUMPS IN STOCK Armstrong Machine Co. Inc. Pocahontas, IA 50574 USA 712-335-4131 ~ 24 Hours 7 Days a Week • Fax: 712-335-4565 800-831-4527 USA & Canada (8AM to 4PM Monday-Friday) Hydraulic Grout Pumps 5”, 6”, & 7-1/2” 33 WorldWide Drilling Resource ® JULY 2020 WTR