. The American florist : a weekly journal for the trade. Floriculture; Florists. i887. The American Florist. 63. „Je "Down Hill" and "Level" systems, the pipe is for convenience divided into sections A-B, B-C, etc, in each of which a pressure is exerted in the direction from its higher towards its lower end equal to the weight of a cylindrical col- umn of water with diameter equal to that of pipe, and height equal to difference of elevation between highest and lowest points, and temperature a mean between that of its extremes. (This last assump- tion is not rigidly exact, b
. The American florist : a weekly journal for the trade. Floriculture; Florists. i887. The American Florist. 63. „Je "Down Hill" and "Level" systems, the pipe is for convenience divided into sections A-B, B-C, etc, in each of which a pressure is exerted in the direction from its higher towards its lower end equal to the weight of a cylindrical col- umn of water with diameter equal to that of pipe, and height equal to difference of elevation between highest and lowest points, and temperature a mean between that of its extremes. (This last assump- tion is not rigidly exact, but the error is too small to be of consequence.) Using the formula given in Prof Rankine's "Steam Engine," the following values were obtained for' the weight of a cylin- der of water four inches in diameter and one foot high: Let it be assumed that the mean tem- perature of the column of water A-B, ex- tending from the bottom of heater inside to center of first elbow, is 200° Fahr.; that the temperature of the correspond- ing column outside, from center of last elbow to bottom of heater, is 100°; and that the temperature at the bend farthest away from heater is 140°; then the aver- age temperature of the top pipe will be, approximately, 170°, and of the bottom pipe 120°. Assume the vertical distance from bottom of heater to center line of highest point in pipe to be in each case 5 feet. Let the other vertical measure- ments be as figured in the diagrams. Let pressures operating in the direction of flow be designated as plus, and those in the opposite direction as minus. Then in Fig. I we have : TTpiffht Tempe- Weight | W'ght of Heignt, per foot. ! Column. Column A B 3 feet 200 B C 2 feet 170 j { i 1 105S62 (I) Total rainu 5 pressures = Column D E ft. 140 EFi 2 ft. 1 120 FG 24fl. 1 100 1 ' 1 ! (2) Total plu pressures = 26,9525 Deducting (i) from (2) we have for re- sultant pre
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