Steam generator (boiler)

Stone-Vapor One of the best-known designs is the Stone-Vapor. The inner casing of the boiler forms a vertical bell, with an outer airtight cylindrical casing. The oil or gas burner is mounted at the top, above the coils, and facing downwards. The heating element is a single tube, arranged into a number of helical cylinders. The first helices (in the flow direction) are small-diameter tubes, wrapped in large diameter turns. Succeeding turns are coiled inside this and the tube is of progressively increasing diameter, to allow for a constant flow rate as the water evaporates into steam and forms bubbles. The steam outlet is from the final turn at the bottom of the inner helix. The outlet is approximately 90% steam (by mass) Clayton steam generators are described as capable of full-range modulation, meaning that steam output can be adjusted continuously in response to changing load demands. According to company technical literature, the design has relatively low water content compared with traditional firetube boilers and is intended to support rapid start-up from cold conditions. The heating surface consists of a coil mounted within a cylindrical casing, arranged as stacked flat spiral sections rather than helical cylindrical layers. == See also ==