what is the purpose of a boiler?
boiler makes steam. what is done with that steam will vary. it can be used to drive an engine, as with a locamotive, or generate electricity. it can be used to heat a building (old fashioned radiators used steam-boilers). in the soyfoods factory i worked in many years ago, it was used to cook whatever we had in a steam-kettle. i'm sure there's more, but you get the idea.
