The San Xavier Reservation, near Tucson, Arizona, was once known for growing organic alfalfa for racing horses and other livestock, as well as other produce. And until 2001, the 900-acre farm depended on ground water wells for irrigation. However, due to urban development, ground water demand increased , drastically depleting the supply.
“The low pressures in the underground irrigation distribution system offered a unique challenge,” said Jeff Riley, supervisory civil engineer with the U.S. Bureau of Reclamation.
Despite the complicated and usual application, Singer Valve stepped in and performed hydraulic modeling to properly asses the specific needs of the area. In search of the best solution, Singer built a simulator to mimic the behavior of the San Xavier irrigation system. After testing a standard proportional integral derivative (PID) on the simulator, Singer’s Vice President of Technology and Applications, Kari Oksanen, wrote a custom algorithm for a programmable logic controller (PLC).
Following 11 algorithm revisions, Oskanen’s program stabilized water levels within a few minutes compared to the standard PID’s performance of two days. Singer then designed and implemented the following customized equipment for San Xavier’s flood irrigation system:
• One 16-in. globe style valve
• Eight 12-in. angle style valves
• Five storage tanks (each with its own control panel)
Despite having a custom algorithm to support the system’s design, controlling flow intake, high pressure and each tank’s water level electronically and simultaneously throughout the entire water system was challenging. According to Dave Buchwald, a fluid dynamics specialist, this project was among the most complicated that the team had ever seen.
However, according to Oksanen, there are great benefits to such a system, “Controlling levels electronically is very difficult. But the beauty of PLC is that there is no limit to what you can tell it to do.”
With Singer’s help, San Xavier now has a sophisticated flood irrigation system capable of controlling water pressure and levels electronically and simultaneously. The custom anti-cavitation trim works at all flows and valve openings and the customized proprietary algorithm handles level control while limiting flow and preventing inlet surges.
Did You Know…
Singer can customize the anti-cavitation trim to meet specific requirements such as limiting flow, improving already impressive low flow stability, reducing closing surges and improved PLC control over a wide range of flows. To learn more about the variety of solutions available to engineers, contractors, and governments, visit www.singervalve.com.
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