Flume Venturi

Parshall flume— Venturi flume invented by Parshall. 

Eiquid Flow Measurement in Open Channels Using Thin Plate Weirs and Venturi Flumes, ISO 1438-1975(E), International Organization for Standardization, Geneva, Switzerland, 1975. 

Alternatively, a flume can be employed where the rate of fall of a stream is slight or where the stream contains a large quantity of solid material (silt or debris). The most widely used is the venturi flume (Fig. 6.7c) for which the volumetric flow can be determined from03 ... 

Head-type flowmeters include orifice plates, venturi tubes, weirs, flumes, and many others. They change the velocity or direction of the flow, creating a measurable differential pressure, or "pressure head," in the fluid. Head metering is one of the most ancient of flow detection techniques. There is evidence that the Egyptians used weirs for measurement of irrigation water flows in the days of the Pharaohs and that the Romans used orifices to meter water to households in Caesar s time. In the 18th century, Bernoulli established the basic relationship between the pressure head and velocity head, and Venturi published on the flow tube bearing his name. 

This chapter discusses the unit operations of flow measurements and flow and quality equalizations. Flow meters discussed include rectangular weirs, triangular weirs, trapezoidal weirs, venturi meters, and one of the critical-flow flumes, the Parshall flume. Miscellaneous flow meters including the magnetic flow meter, turbine flow meter, nutating disk meter, and the rotameter are also discussed. These meters are classified as miscellaneous, because they will not be neated analytically but simply described. In addition, liquid level recorders are also briefly discussed. 

Flow meters fall into the broad category of meters for open-channel flow measurements and meters for closed-channel flow measurements. Venturi meters are closed-channel flow measuring devices, whereas weirs and critical-flow flumes are open-channel flow measuring devices. 

Converging zone—The portion in a venturi meter, Parshall flume, or Palmer-Bowlus flume where the cross section is progressively reduced. 

Venturi flume—An open-channel measuring device with a longitudinal section that is shaped like a venturi meter. 

Palmer, H.K., Bowlus, F.D. (1936). Adaptation of Venturi flumes to flow measurements in conduits. Trans. ASCE 101 1195-1239. (P) (relating to H.K. Palmer)... 

Cone, V.M. (1916). A new irrigation weir. Journal of Agricultural Research 5(24) 1127-1143. Cone, V.M. (1917). Divisors. Bulletin 228. Agricultural Experiment Station, Fort Collins CO. Cone, V.M. (1917). The Venturi flume. Journal of Agricultural Research 9(4) 115-129. 

Wells, E.A., Gotaas, H.B. (1958). Design of Venturi flumes in circular conduits. Trans. ASCE 123 749-771 123 774-775. 

Parshall, RL. (1925). The improved Venturi flume. Trans. ASCE 89 841-880. 

Anonymous (1935). P.S. Wilson, Secretary AWWA. Water Works Engineering 88(23) 1318. P Anonymous (1949). Wilson, Percy S. Who s who in engineering 6 2193. Lewis New York. Wilson, P.S., Wright, C.A. (1920). A study of the Venturi Flume as a measuring device in open channels. Engineering News-Record %5 Qy. 452-457 85(26) 1223-1224. 

Flow rate is typically measured in gallons per minute (gpm) or gallons per hour (gph). A variety of devices can be used to accomplish flow measurement. Common examples of flow measurement devices are orifice plates, venturi nozzles, nutating disc meters, turbine flow meters, oval gear meters, rotameters, pitot tubes, weir and flume, and flow transmitters. Figure 7-4 shows a few examples of flow-measurement devices. 

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