water-tube boiler

[ waw-ter-toob, -tyoob, wot-er- ]
/ ˈwɔ tərˌtub, -ˌtyub, ˈwɒt ər- /

noun

a boiler for generating steam by passing water in tubes (water tubes) through flames and hot gases.
Compare fire-tube boiler.

Origin of water-tube boiler

First recorded in 1870–75