Some firetube boilers are also referred to as Scotch Marine Boilers, due to their common use on ships in a horizontal configuration. They are very durable, easy to service and work well with consistent and predictable loads. Firetube boilers come in 2, 3, and 4 pass configurations, design pressures from 15 psig to 300 psig, capacities up to 2,500 BoHP in a single boiler, and can be used to produce steam or hot water. There are also vertical firetube boilers, which have a single pass and reduced capacities, under 150 BoHP. Finally, there are firebox boilers that offer reduced capacities, under 150 BoHP and pressures of 15 psig or less.

There are two basic firetube designs: “wetback” and “dryback.” The wetback design has a water-cooled, rear face of the combustion chamber heating surface. This provides great heat transfer to the water and less stress on the rear tube sheets, prolonging the boiler life. The benefits of the wetback design are higher efficiency, lower maintenance costs, and longer life expectancy. The dryback design has an open box rear combustion area, backed or surrounded by refractory. This provides a more simplistic design that is easier to service. The benefits of the dryback design are lower first cost and ease of service. Learn more about how wetback and dryback boilers compare.

In certain areas of the country, there are state-specific laws regarding the design of boilers, and firetube manufacturers have adjusted their designs accordingly. One such case has been in Ohio, where there are restrictions on the amount of heating surface to run a boiler without an operator. This is commonly referred to as an “Ohio Special Boiler.” However, the laws in Ohio have recently changed to allow boilers that exceed the heating surface requirement to be run without an operator by providing some additional monitoring and documentation.

Lathrop Trotter partners with Superior Boiler Works to offer their full line of firetube boilers.

Superior Firetube Boilers

Superior Firetube BoilersSuperior firetube boilers are designed for maximum efficiency, reliability, durability in the most demanding environments, dual fuel capable, and are available with NOx reduction technology to sub 9 ppm.  They offer:

  • Apache 2-pass Dryback Firetube Boiler – sizes ranging from 10 to 2,400 BoHP
  • Mohawk 3-pass Dryback Firetube Boiler – sizes ranging from 30 to 1,000 BoHP
  • SX6 2-pass Wetback Firetube Boiler – sizes ranging from 100 to 2,500 BoHP
  • Seminole 3-pass Wetback Firetube Boiler – sizes ranging from 70 to 2,400 BoHP
  • Mohican 4-pass Wetback Firetube Boiler – sizes ranging from 50 to 1,500 BoHP
  • Ohio Special – sizes ranging from 80 to 250 BoHP
  • Triad Vertical Firetube Boiler – sizes ranging from 10 to 150 BoHP
  • Arrowhead 3-pass Dryback Firebox Boiler – sizes ranging from 10 to 100 BoHP
  • Osage 3-pass Wetback Firebox Boiler – sizes ranging from 10 to 100 BoHP
  • Creek Condensing Hot Water Firetube Boiler– sizes ranging from 300 MBH to 6,000 MBH
  • Ancillary Boiler Room Equipment
    • Deaerators (Spray, Tray, Dual Tank)
    • Feedwater Tanks
    • Condensate Return/Receivers
    • Blowdown Separators