Sewerage and Sewage Disposal / by Henry Robinson.

Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: Sewerage and Sewage Disposal / by Henry Robinson. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    by means of the diagram for any particular sewer running full, these scales supply a means of obtain- ing the discharge and velocity, by direct measure- ment on the diagram, when the sewer is running at any given depth of flow. Thus, to find the dis- charge from the 3-foot circular sewer in the example given above, when running say £ full, measure (with a pair of dividers) the distance from the arrowhead to ’25 (£) on the scale of modifications for dis- charges—circular culverts. This distance must then be set off from the point on the vertical scale corresponding to the discharge when running full to arrive at the required discharge. In the example, the distance will be set off from 24'2 downwards to 3*4 cubic feet per second. The scale of modifications for velocities is applied' in a similar manner to the (inclined) scale of velo- cities on the diagram, the measurements being set off down to the right or up to the left according as they are taken from the — or + side of the arrow- head. In the example, the distance will be set off from 3-42 downwards to the right to 2-48, which is the required velocity in feet per second. Similarly, when the same sewer is running * 6 full, the velocity is 3‘67 feet per second. bor the 4-foot oval sewer running £ full the velocity is 2^52 and the discharge 3'3, the scales for oval sewers being used. o