. Principles and practice of plumbing . e water a matter offact, however,waterbacks andcoils transmit only about 25 per cent, of their possible capac-ity. This is due to the fact that they are placed in the fire-box in the position least likely to affect the stove for otherpurposes, and therefore are not exposed to the hottest coalsand gases of the fire. Furthermore, they are partly coveredby ashes, soot and dying coals, and in the case of cast ironwaterbacks, the walls usually are of too great thickness totransmit the maximum amount of heat. In many caseswaterbacks and coils are coa
. Principles and practice of plumbing . e water a matter offact, however,waterbacks andcoils transmit only about 25 per cent, of their possible capac-ity. This is due to the fact that they are placed in the fire-box in the position least likely to affect the stove for otherpurposes, and therefore are not exposed to the hottest coalsand gases of the fire. Furthermore, they are partly coveredby ashes, soot and dying coals, and in the case of cast ironwaterbacks, the walls usually are of too great thickness totransmit the maximum amount of heat. In many caseswaterbacks and coils are coated with incrustations of limeor magnesia that still further reduce their transmittingcapacities. New or clear cast iron waterbacks, under ordi-nary conditions, will heat from ordinary temperature to 200degrees Fahrenheit from 25 to 35 gallons of water per hourfor each square foot of exposed surface. With an ordinaryfire, one square foot of exposed waterback surface will heatabout 25 gallons of water per hour, while with a fire such as. Digitized by Microsoft® 256 Principles and Practice of Plumbing is used for baking or roasting, one square foot of surfacewill heat about 35 gallons of water per hour. However, the average size of waterback contains only110 square inches or about 2/3 square foot of exposed sur-face, and water for domestic uses is seldom heated to abovethe temperature of 180 degrees Fahrenheit, therefore anordinary waterback with an average fire will heat fromordinary temperature to boiling point about 17 gallons ofwater per hour, or from ordinary temperature to 180 de-grees Fahrenheit about 21 gallons of water per hour, whilewith a fire such as is used for cooking or baking it will heat 23 gallons of water to the boilingpoint, or 27 gallons of water to atemperature of 180 degrees Fahren-heit. Wrought iron pipes will heatfrom 30 to 40 gallons of water un-der the same conditions, and copperpipes will heat from 45 to 60 gallonsper hour for each square foot of sur-
Size: 2024px × 1234px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, bookidcu3192402142, bookyear1922
