HOT-WATER BOILER Russian patent published in 1998 - IPC

FIELD: thermal engineering; heating-system boilers. SUBSTANCE: hot-water boiler has water space enclosed in sealed body incorporating shell, front and rear tube plates 2 and 3, respectively, and flame chamber 4. Placed in water space are fire tubes 8 communicating through their inlet sections with flame chamber 4 and through outlet sections, with header which communicates with chimney stack. Boiler is provided, in addition, with heating elements in the form of FildeТs tubes. Each external tube 9 of heating element is placed in fire tube 8 in a certain space relation to it. Internal tubes 10 of heating element are connected through their inlet ends to feedwater supply line 12; open ends of external tubes 9 are connected to water space of boiler. EFFECT: enlarged heating surface and improve heat transfer and reliability of boiler. 1 dwg