Rensselaer Republican, Volume 22, Number 45, Rensselaer, Jasper County, 10 July 1890 — Effects of Deposit in Boilers. [ARTICLE]

Effects of Deposit in Boilers .

Safety Valve. A large proportion of ruptures and explosions of steam boilers is directly due to incrustation. Water that is apparently free from impurities, And looks sparkling and bright to the casual observer, has, to a greater or less degree, mineral salts held in solution. A very few grains of solid matter to the gallon, whether dissolved or suspended, being thrown down by boiling or evaporation, will in a short time, by negligence in the use of the blow and infrequent cleaning, cause a deposit to be formed on the tubes and shell of the boiler of unlimited thickness. The deleterious effect of this formation is due to its non-conductive-ness. A deposit one-sixteenth of an inch in thickness has been shown by experiment to require 15 per cent, more fuel, while a deposit of a quarter of an inch, 60 per cent more to do the s>ame amount of work as a clean boiler. It is readily apparent that it does not require a great quantity of sediment to very effectually increase the fuel bill and add materially to the cost of production. Not only is more heat necessary to raise the water to the required temperature, but it has not the cooling effect it otherwise would have on the plates. The additional heat soon reduces the metal to the granular and brittle state of cast-iron. The excessive heat causes bags and blisters, necessitating expensive repairs, and in numerous cases only the cohesiveness of the layers of scale averting a serious disaster. Corrosion often takes place between the incrustation and metal, reducing the shell and tubes to a dangerous thinness, in many cases one-half or a quarter their usual thickness. Engineers and boiler operators can not be too careful and observing. Feedwater should enter a boiler in such a way as to carry the impurities toward the blow-off cock. These should be open for awhile two or three times e, day and, in case of bad water, much oftener. r ' l A boiler should not be emptied while it is hot, or enough heat is retained in the brickwork.to bake the deposit, as it is then almost an impossibility to remove the scale. Frequent washing out of boilers is a necessity.