Feed-water treatment is essential in boilers, feed-systems, etc., more particularly in modern boilers of a high evaporative rate. (The faster a steam-boiler or generator will convert water to steam, the more rapidly will the solids in the water concentrate up.) So, large and small water-tube boilers, the typical fire-tube packaged boiler, and steam generators are all examples of this in varying degrees.
(Kung mas mabilis magpasingaw ng tubig ang isang boiler, mas mabilis ang pag-ipon ng mga di kanais-nais na matitigas na mga bagay sa boiler). Halimbawa nito ang mga maliliit at malalaki na water-tube boiler, ang tipikal na fire-tube packaged boiler, at steam generator.