Steam heater with helical coils - having greater flow area for condens. zone than desuperheating or condensate cooling

摘要

Heater using steam as the heating medium consists of a shell enclosing a series of helical coils mounted around a central axis, the liquid to be heated flowing through teh coils. The shell space into which the steam is passed is divided into several zones, one for taking the superheat out of the steam, one for the condensation and one for subcooling the condensate. An annular baffle surrounds the upper section of the coils while there is an annular gap around the section where condensation occurs between the coils and the vessel wall. In the lower subcooling section there is also a baffle. For use with ht. exchangers where fluids are being heated. In the desuperheating zone the ht. transfer is improved by a higher flow velocity over the coils. The effectiveness is in part measured by the pressure drop. Thus a pressure drop in this zone is of advantage. In the condensation zone, the ht. transfer mechanism is different and pressure drop is no advantage. In the condensate sub-colling zone, ht. transfer is again proportional to flow and a pressure drop is an advantage. The heater described combines these features.