MOBILE FLUME FOR PIPE-FLOW

Discharge measurement in partially filled pipes, as occurs in sewage a nd drainage engineering, is considered with an improved device. The so -called pipe flume is suited for mobile discharge measurement either f or a single discharge reading or for the determination of daily or wee kly hydrographs. It can easily be mounted in commercially fabricated p ipes, and sediment transport does not detract from its accuracy. The d evice has been extensively tested in a hydraulics lab and the device h as an accuracy of +/- 5% in optimum field conditions. Simplifications compared to the original design include the head determination in the cylindrical container, by which surface fluctuations are practically r emoved, and effects of pipe,slope are eliminated. A discharge-head equ ation is established for pipe flumes having a diameter larger than 200 mm, where effects of scale are negligible. The discharge-head equatio n accounts for the pipe filling and the constriction rate, as well as for the position relative to the pipe outlet section.