page_title: Boiler water
section_title: Early practice
hierarchical_section_title: Boiler water / Early practice
caption_attribution_description: Weir steam boiler feedwater pump
context_page_description: Boiler water is liquid water within a boiler, or in associated piping, pumps and other equipment, that is intended for evaporation into steam. The term may also be applied to raw water intended for use in boilers, treated boiler feedwater, steam condensate being returned to a boiler, or boiler blowdown being removed from a boiler.
context_section_description: Impurities in water will leave solid deposits as steam evaporates.  These solid deposits thermally insulate heat exchange surfaces initially decreasing the rate of steam generation, and potentially causing boiler metals to reach failure temperatures.  Boiler explosions were not uncommon until surviving boiler operators learned how to periodically clean their boilers.  Some solids could be removed by cooling the boiler so differential thermal expansion caused brittle crystalline solids to crack and flake off metal boiler surfaces.  Other solids were removed by acid washing or mechanical scouring.  Various rates of boiler blowdown could reduce the frequency of cleaning, but efficient operation and maintenance of individual boilers was determined by trial and error until chemists devised means of measuring and adjusting water quality to minimize cleaning requirements.
caption: Boiler feed water pump
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