The Connector - Spring 2008 - (Page 27)

RWAU Spring 2008 a flow through a valve. The flow is the reason for two valves parallel of each other with one valve being smaller. The example above indicated that to meet the normal maximum flow through a 12-inch pipe would require at least a 6-inch valve. However, if you try to run 20 or 30 GPM through that 6-inch valve is will cause cavitation of the valve, so. To reduce this condition, a smaller valve (such as 1 1/2 inch or 2 inch valve) is put in parallel. The smaller valve is set at a 5 to 10 psi higher than the larger valve. The smaller handles all the flow until it reaches its capacity, and then the pressure begins to decrease until it reaches the set point of the larger valve and then the larger valve begins to open and does its part with the larger flows. When the flows reduce, the larger valve will close fi rst as the downstream pressure increases and then the smaller valve will once again control the downstream pressure and flow. EQUAL FLOW VOLUME pacity--Equal Flow Volume and service life Pipeline at 5-7 FPS Velocity .785 x 1’ x 1’ x 5 ft/sec = 4 cfs or 1761.54 Pressure Reducing Valve at 20-25 FPS Velocity 4 cfs/20 fps = .2 f 2/ .785 = .25 f 2 = .5 ft or 6 inch Meter Reading by Radio Communication continued from page 25 well, positive displacement type meters may have a short life within your system. • Talk to other systems. There are many that have been using radio for some time now. Find out their experiences with range, cast-iron lids, battery life, accuracy, whether they will work through a foot of snow, etc. Rural Water employees may be able to steer you in the direction of some of these systems if needed. • Are you comfortable with the supplier? When you purchase the system, you’re locking yourself into buying this same brand of meter for the foreseeable future in order to be compatible with the radio/software system you’ve purchased. Will they be there to provide continuing tech support if needed? Bottom line is, while a radio read system may be a “nobrainer” for some systems, it may be tough to justify for others. You really need to look at the economics when contemplating purchasing such a system. Make sure you take into account as many of the factors as possible, and even consider enlisting the help of a local “bean counter” if necessary. You might even say it’s a lot like purchasing a new car—sometimes you really need to replace the old beater, and sometimes you just want that new car smell and all the cool gizmos! Over 60 Years Experience BUSH & GUDGELL, INC. Engineers • Planners • Surveyors • WATER RESOURCE DEVELOPMENT • MUNICIPAL ENGINEERING • WATER TREATMENT • WATER SYSTEMS • SURVEYING 525 South 300 East, Suite 100 Salt Lake City, Utah 81111 (801) 364-1212 • Fax (801) 364-1225 www.bushandgudgell.com 205 East T abernacle #4 St. George, Utah 84770 (435) 673-2337 • Fax (435) 673-3161 27 369321_bush.indd 1 The Connector PM 4/9/08 3:06:44 http://www.bushandgudgell.com

Table of Contents Feed for the Digital Edition of The Connector - Spring 2008

The Connector - Spring 2008 Table of Contents President's Message Executive Director's Comments Letters From Readers Legislative Update RWAU Board and Staff Rural Water News Bees on the Pipeline, Jim Watts How Important are our Public Works People? Curtis Ludvigson A "What" Protection Plan? Erin Borger Meter Reading by Radio Communication, Terry Smith Advanced Distribution, Chuck Jeffs Where in Utah?

The Connector - Spring 2008

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