Trabue Industrial Systems

Firetube boilers are available for low or high pressure steam, or for hot water applications. Firetube boilers are typically used for applications ranging from 15-1500 horsepower. A firetube boiler is a cylindrical vessel, with the flame in the furnace and the combustion gases inside the tubes. The furnace and tubes are within a large vessel, which contains water and steam.

The firetube construction provides some characteristics that differentiate it from other boiler types.  Because if its vessel size, the firetube contains a large amount of water, allowing it to respond to load changes with a minimum variation in steam pressure.

Steam pressure in a firetube boiler is generally limited to approximately 350 psig. To achieve higher pressure, it would be necessary to use very thick shell and tube sheet material. For this reason, a watertube boiler is generally used if pressure above 350 psig design is needed.

Firetube boilers are usually built similar to a shell and tube heat exchanger.  A large quantity of tubes results in more heating surface per boiler horsepower, which greatly improves heat transfer and efficiency.

Firetube boilers are rated in boiler horsepower (BHP), which should not be confused with other horsepower measurements.

The furnace and banks of tubes are sued to transfer heat to the water. Combustion occurs within the furnace and the flue gases are roughed through the tubes to the stack outlet. Firetube boilers are available in two, three and four pass designs. A single "pass" is defined as the area where combustion gases travel the length of the boiler. Generally, boiler efficiencies increase with the number of passes.

Firetube boilers are available in either dryback or wetback design. In the dryback boiler, a refractory-lined chamber, outside of the vessel, is used to direct the combustion gases from the furnace to the tube banks. Easy access to all internal areas of the boiler including tubes, burner, furnace, and refractory, is available from either end of the boiler. This makes maintenance easier and reduces associated costs.

The wetback boiler design has a water cooled turn around chamber used to direct the flue gases form the furnace to the tube banks. The wetback design requires less refractory maintenance; however, internal pressure vessel maintenance, such as cleaning, is more difficult and costly. In addition, the wetback design is more prone to water side sludge buildup, because of the restricted flow areas near the turn around chamber.

Firetube boilers are best suited for heating and industrial process applications requiring pressures below 250 PSI, and are available in sizes from 600,000 btu/hr to 50,000,000 btu/hr.

Firetube boilers do require periodic maintenance and inspection as well as the use of operating safety precautions such as flame safe guards and boiler controls.

Clicking on the link to Cleaver-Brooks will take you to various models and sizes of boilers. Every application for generating steam or hot water is covered by this large selection of boiler offerings. We will be happy to assist you with your choices if you like. Thanks for visiting. Visit Cleaver-Brooks.