Jim Mimlitz, NRI<\/p><\/div>A topic of immense concern to Levee Districts is the tracking of pump flow rate (e.g.. gallons per minute), as well as the totalization of pumped volume (e.g.. total gallons, cubic feet, or acre-feet). Flow-rate is important, as the Districts are able to trend instantaneous pump performance in real-time, which provides a measure of the health of the pump. Total accumulated pumped volume is also important, as certain Districts are reimbursed by the Federal Government for the pumped water on a per-volume basis.<\/p>\n
![\"Levee](\"https:\/\/wireless-telemetry.com\/blog\/wp-content\/uploads\/2014\/09\/IMG_3475.jpg\")
<\/a>Levee Pump Station<\/p><\/div>\n
The automatic measurement of this data\u00a0poses several challenges to the Telemetry Engineer:\u00a0 Typical flow meters in the potable water industry consist of a turbine or propeller suspended within the flow tube.\u00a0 However, pumped ditch water contains a high percentage of solids, such as branches, leaves, debris, etc..\u00a0 Thus mechanical flow meters, whose moving parts\u00a0could clog the pipeline and restrict flow,\u00a0should be\u00a0ruled out as a source of reliable flow data.<\/p>\n
Inline magnetic flow meters are very accurate and have no moving parts, and\u00a0are therefore the measurement instrument gold standard<\/em> for\u00a0this application.\u00a0 However, the equipment and installation costs of an inline flowmeter can be considerable and\u00a0often not in-line with\u00a0a project’s budget.<\/p>\n NRI was recently tasked with monitoring pump flow-rate and totalization at two Levee Districts using computerized estimation techniques.\u00a0 The goal was to provide reasonably-accurate flow rate and totalization, yet without the expense of acquiring and installing inline magnetic flowmeters.<\/p>\n One crude method would have been to simply assume a typical flow rate, and scale the pump runtime accordingly to estimate total\u00a0pumped volume.\u00a0 However, this method would\u00a0fail to take into account changing hydraulic conditions.\u00a0 For example, if the river level was high, the true\u00a0pump flow rate would decrease<\/em> due to an increased static head.\u00a0 Alternatively, if the ditch level was high, the true pump flow rate would increase<\/em> due to a decreased static head.<\/p>\n In\u00a0the course of these two projects, Mechanical Engineer John Neyens, PE\u00a0at Klingner & Associates (Quincy, IL)<\/a> requested that a more sophisticated estimation technique be employed — one that takes into account the specific characteristics of the pump (the pump curve) as well as the dynamic hydraulic characteristics, which vary based upon the ditch and river levels (the system curve).\u00a0 The meanings of these curves, and their interrelationships, are well-described at engineeringtoolbox.com<\/a>.<\/p>\n The following equations, provided by\u00a0Neyens,\u00a0describe one of the levee pumps and its associated hydraulic system:<\/p>\n System Curve:<\/strong><\/p>\n TDH<\/strong> = (1.509690E-9)*F^2 \u00a0+ \u00a0(4.40974568E-6)*F\u00a0 + \u00a0(SH)<\/p>\n Pump Curve:<\/strong><\/p>\n TDH<\/strong> = (-146.217E-15)*F^3\u00a0 +\u00a0 (-1.830671155E-9)*F^2\u00a0 +\u00a0 (-139.47674085E-6)*F\u00a0 +\u00a0 (52.768)<\/p>\n where<\/p>\n TDH<\/strong> = Total Dynamic Head<\/p>\n F<\/strong> = Flow Rate (Gallons Per Minute)<\/p>\n SH<\/strong> = Static Head<\/p>\n The flow rate is\u00a0calculated by solving for the root(s) of the following non-linear equation:<\/p>\n TDH (Pump Curve)\u00a0 –\u00a0 TDH (System Curve)\u00a0 =\u00a0 0<\/strong><\/p>\n (-146.217E-15)*F^3\u00a0 +\u00a0 (320.98115E-12)*F^2\u00a0 +\u00a0 (-143.88648E-6)*F\u00a0 +\u00a0 (52.758-SH)\u00a0 =\u00a0 0<\/p>\n The above equation may have multiple roots, so the solution should be bounded\u00a0within\u00a0a reasonable range.<\/p>\n Solving cubic equations using iterative, non-linear techniques is generally beyond the capability of most industrial automation controllers.\u00a0 However, this is an area where the computational power of Navionics Research’s\u00a0RTU (IBM-compatible PC architecture) can be leveraged.\u00a0 In this project,\u00a0our RTU utilizes\u00a0the secant method<\/a> of solution convergence to update the rate-of-flow in Gallons-Per-Minute\u00a0every 5 seconds.\u00a0 The total pumped volume was also continuously updated using discrete calculus (the time integral of the flow-rate) —\u00a0thereby providing totalization\u00a0in Gallons.<\/p>\n It is important to note that this solution requires knowledge of the Static Head, which requires instantaneous telemetry measurements of the water levels in both the ditch and in the river.\u00a0 This was achieved using\u00a0Navionics Research’s\u00a0Pneumatic\u00a0Bubbler System, which is\u00a0described in another article <\/a>here on\u00a0our website.<\/p>\n The following Telemetry History Charts\u00a0from a Levee District’s SCADA System illustrate the results of this effective technique:<\/p>\n Telemetry History Charts from a Levee District’s SCADA System, Illustrating the Results of the Automatic Calculation of Rate-of-Flow and Total Gallons Pumped.<\/p><\/div>\n Would this type of sophisticated flow calculation benefit your Levee District or potable water system?\u00a0 Give us a call.\u00a0 Our Telemetry\/Control Systems are designed to leverage this exciting technology; and we\u2019ll be glad to discuss this with you in further detail.<\/p>\n Telemetry, SCADA, & Controls Newsletter<\/strong><\/p>\n Was this article helpful?\u00a0 Would you be interested in receiving updates such as these in our occasional email-delivered newsletter?\u00a0 If so, here’s our sign-up page:<\/p>\n Subscribe to\u00a0Navionics Research’s\u00a0“Telemetry, SCADA, & Controls Newsletter”<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" A topic of immense concern to Levee Districts is the tracking of pump flow rate (e.g.. gallons per minute), as well as the totalization of pumped volume (e.g.. total gallons, cubic feet, or acre-feet). Flow-rate is important, as the Districts are able to trend instantaneous pump performance in real-time, which provides a measure of the …<\/span> Read More →<\/span><\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":95,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,16],"tags":[64,66,85,96,111,128,134,144,145],"class_list":["post-155","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-applications","category-sensors","tag-flow-calculation","tag-flow-estimation","tag-levee-district","tag-numerical-methods","tag-pump-curve","tag-scada","tag-secant-method","tag-system-curve","tag-telemetry"],"_links":{"self":[{"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/155","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=155"}],"version-history":[{"count":0,"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/155\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=\/"}],"wp:attachment":[{"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=155"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=155"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wireless-telemetry.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=155"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a>