Report on the supply of water to the metropolis. Appendix No. II-[IV].

  • Great Britain. General Board of Health
Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: Report on the supply of water to the metropolis. Appendix No. II-[IV]. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    Table showing the Velocities j the Sectional'Areas; and the Discharges ^^m.^,_ of the Flow through a Main Line of Pipes 4 inches diameter by the ^ introduction of Tributaries, each 3 inches diameter, and running in the following order:— Main Line And Junctions. Distance of Junctions from Head of Main Line. Mean Ve- locity in Feet per Second. Section in Inches. Discharge in Cubic Feet. l\X&in Xjinc. Feet. 3-5 9-3 ] • Junction. 5 3-3 0-58 9-67 2. i Do. 25 1-9 6-56 10«16 3. Do. 45 2-3 6-56 12-17 4. Do. 65 2-5 6-56 13-33 5. Do. 85 2-9 6'56 15-47 6. Do. 10 2-8 6-56 14-93 ;. Do. 30 2-9 6-56 15-39 8. Do. 50 3-05 6*56 15-8 9. Do. 70 3-09 6-56 16-15 0, Do. 90 3-2 6-56 17-12 Diagram illustrating Velocity. 7 At what point would the water be dammed up in the tributary channels by the rapidly flowing water in the main, that is, after how many junctions had been made?—An inspection of the diagrams Nos. 3, 4, 5, will in some measure illustrate this question; it would appear that at an inclination of 1 in 240 before the introduction of any junctions, the water is backed up in the junctions, owing to the flow in the main line. There is no experiment to show the point at which the water would be dammed up in the tributary channels by the water in the main. You have found the present experiments too restricted to ascertain the limits of velocity and distance ; will you favour the Board with an idea of the scale on which you would require to try these experiments, in order to acquire sufficient data to enable you to lay down a theory on this subject?—The experiments have been far too restricted to enable any theory to be laid down on the subject; they would require to be made with pipes and channels of various forms, of large dimensions, and various lengths. What, approximatively, judging from past experience, would be the cost of such a series of experiments?—^The cost can only be ascertained Irom knowing to what extent the late Committee would consider it necessary to carry them. The table, page 26, gives the increased discharge for each additional junction; what was the difference of velocity at the outlet when 1, 2, 3—10 junctions were added ?—I have no sections of these experiments of this size from which I can calculate the velocities but