. The book of the garden. Gardening. HEATING BY HOT-WATER PIPES. 161 float imparts centrifugal force to the water, causing it to rise higher at the sides than at the centre of the boiler; and the velocity with which the float moves determines the extent of this deviation from the level. According to Hood's calculations as to the circulating power of this apparatus, it would appear that, if the velocity of rotation be such as will impart a centri- fugal force sufficient to raise the water in the boiler 1 inch higher at the periphery than in the centre, there will then be a pressure of 246^ grai
. The book of the garden. Gardening. HEATING BY HOT-WATER PIPES. 161 float imparts centrifugal force to the water, causing it to rise higher at the sides than at the centre of the boiler; and the velocity with which the float moves determines the extent of this deviation from the level. According to Hood's calculations as to the circulating power of this apparatus, it would appear that, if the velocity of rotation be such as will impart a centri- fugal force sufficient to raise the water in the boiler 1 inch higher at the periphery than in the centre, there will then be a pressure of 246^ grains on the square inch upon the pipe a more than upon the pipe b, if the temperature of the water be about 180°. This additional pressure, he ob- serves, will allow the water in the pipe a to descend 42 feet below the boiler, if it does not lose more than 6° of heat before it return back again through the pipe b; if it loses 10°, it will descend only 25^°. M. Bonnemairfs mode of heating.—Fig. 174 shows a section of this early mode of Fig. heating, in which a is the boiler; d a feed- pipe ; o a stop-cock, for regulating the quantity of ascending hot water; b the pipe by which the hot water ascends from the boiler into the heating pipes c c. These heating pipes have a gradual slope towards the boiler, to which the water returns by the pipe e, carried nearly to the bottom. In this way the water, cooled by being circulated through a long series of pipes, is being constantly returned to the lower part of the boiler, where it receives a fresh amount of heat; and being thus rendered lighter, rises up the pipe b, and descends the inclined planes of the pipes, losing a portion of its heat by the way, and, at the same time, increasing in density; the velocity of the current depending on the difference between the temperature of the water in the boiler and that in the descending pipe. At the highest point of VOL. I. the apparatus is a pipe i, furnished with a stop-cock for the
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectgardening, bookyear18
