Wetback Boiler and Dryback Boiler

Wetback Fire tube Boilers

Wetback boiler designs have a water gap between the furnace and back wall, and all of the heat is generated directly into water. Some Dryback designs can be just as durable as wetback designs, but must have a heat balance in the system.The surrounding water absorbs burner heat, helping improve operating efficiency as heat from combustion goes directly into evenly heating water instead of refractory. The wet back boiler design uses separate tube sheets between tube passes which can be more forgiving with load changes.

Wetback firetube boilers offer a more optimal functional footprint, with lift off or split-hinged doors that require no cool-down period and can be opened immediately. While there is no expensive refractory to maintain, internal pressure vessel maintenance (i.e. cleaning and tube removal) can be more involved and challenging.

Dryback Fire tube Boilers

A dryback boiler design means that the rear wall is lined with refractory, which passes combustion gasses from the furnace to multiple tube sheets and reflects burner heat, resulting in exterior radiation losses. The dry back boiler design uses a common rear tube sheet and features convenient fire-side and water-side access.

Dryback boilers have a larger functional footprint due their heavy, vessel-sized rear door which requires sufficient space to open and a cool-down period prior to opening.

ZBG is mainly specialized in industrial boilers, pressure vessels and other products R & D, production and domestic and foreign trade. More information about the difference between two pass wetback boiler and dryback boiler, please contact with our online customer service.