Fire Tube Boilers
Sellers Fire tube boilers were originally designed to solve the problems that are inherent to the traditional scotch marine boiler design. All firetube boilers distribute energy through a collection of water-backed tubes to enable heat transfer. The Sellers Boiler is innovative in how it distributes that energy at the point of combustion, rather than a turnaround chamber. Uniform application of combustion energy eliminates thermal shock and allows relief of any possible energy buildup in the vessel through a rear relief door, which is unique in the industry.
In a traditional Scotch Marine Boiler, by contrast, 100% of the combustion energy feeds into the furnace. Because of its design flaws, the scotch marine boiler still presents the risk of thermal shock, resulting in a myriad of associated issues that will ultimately require significant maintenance and loss of operation time.
The Sellers Fire Tube Boiler Design
Fire Tube Boiler Types
Sellers offers more than one type of fire tube boiler because we understand that different customers have different needs. But despite the differences, each of our boilers comes with the same first-rate quality that Sellers customers have come to expect. Explore our variety of options, including single-pass, two-pass, and three-pass designs.
Sellers Fire Tube Boiler Advantages
Radiant Heat
The most efficient heat transfer occurs where the combustion in the fire-tubes touch the water in the vessel. This is known as the radiant heat of combustion. The Sellers single pass boiler has significantly more radiant heat transfer than a Scotch Marine, with up to 50% of each fire-tube in a Sellers boiler touching the fire, while only the furnace is subject to radiant heat transfer in a scotch marine boiler.
The Sellers immersion fired S-Series steam boiler is a unique patent-pending horizontal single pass firetube boiler designed to burn natural gas. The unique burner assembly delivers pre-mixed air and gas through multiple nozzles. The air-gas mixture is ignited as it exits each flame retaining nozzle at high velocity The resulting flames are long and small in diameter. The flame from each of these nozzles is directed into a 2″ O.D. tube that is completely immersed in liquid. There is a separate tube for each flame with the same amount of heat going into each tube. These small diameter flames burn in the first half of the tube lengths. Therefore, the “fire shines“ on half of the heating surface in the single pass boiler — 50% of the total heating surface is radiant heating surface.
The high percentage of radiant heating surface, the low heat input into each tube, and the even distribution of heat throughout the multiple tubes virtually eliminate thermal stress problems that are common in multiple pass boilers.
- Style: High Efficiency Single-Pass Design
- Burner: Sellers Multi Flame w/ Parallel Positioning
- Size: 40 – 900 HP (1.7 – 37.7mmBTU)
- Burner Operation: Modulating (3:1 on 40-175HP & 4:1 on 200-900HP)
- Emission Rating: 30ppm NOx
- Certifications: ASME, CRN, & UL
- Warranty: 20-Year (Pressure Vessel) / 5-Year (Burner) / 1.5-Year (Parts)
- Fuels: Natural Gas, Propane, & Digester/Methane
- Application: Steam (15-300 PSI) & Commercial Hot Water & Industrial High Temperature Water 350+ Deg F.
The Sellers immersion fired X-Series steam boiler is a horizontal, single pass, firetube boiler designed to burn natural gas. The unique burner assembly delivers pre-mixed air and gas through multiple nozzles. The air-gas mixture is ignited as it exits each flame retaining nozzle at high velocity The resulting flames are long and small in diameter. The flame from each of these nozzles is directed into a 2″ O.D. tube that is completely immersed in liquid. There is a separate tube for each flame with the same amount of heat going into each tube. These small diameter flames burn in the first half of the tube lengths. Therefore, the “fire shines“ on half of the heating surface in the single pass boiler — 50% of the total heating surface is radiant heating surface.
The high percentage of radiant heating surface, the low heat input into each tube, and the even distribution of heat throughout the multiple tubes virtually eliminate thermal stress problems that are common in multiple pass boilers.
- Style: High Efficiency Single-Pass Design
- Burner: Sellers Multi Flame
- Size: 10 – 900 HP (0.4 – 37.7mmBTU)
- Burner Operation: On/Off w/ Pilot Hold
- Emission Rating: 30 & 20ppm NOx
- Certifications: ASME, CRN, & UL
- Warranty: 20-Year (Pressure Vessel) / 5-Year (Burner) / 1.5-Year (Parts)
- Fuels: Natural Gas, Propane, & Digester/Methane
- Application: Steam (15-300 PSI) & Commercial Hot Water & Industrial High Temperature Water 350+ Deg F.
INDUSTRIAL “CLEAN STEAM” BOILER
Sellers chemical-free steam technology simplifies your operation, reduces capital expenditures and maintenance! No water chemical treatment required, no boiler feed equipment required and direct feed with potable water. Inject steam directly into your process without pre-treatment. Another unique innovative solution from Sellers!
- Style: High Efficiency Non-Ferrous Single-Pass Design
- Burner: Sellers Multi Flame w/ Parallel Positioning (40-300HP) & Sellers Multi Flame (10-300)
- Size: 10 – 300 HP (0.4 – 12.6mmBTU)
- Burner Operation: On/Off (10-300HP) & Modulating (3:1 on 40-175HP & 4:1 on 175-300HP)
- Emission Rating: 30ppm NOx
- Certifications: ASME & UL
- Fuels: Natural Gas & Propane
- Application: Chemical Clean Steam (15PSI), Humidification (15PSI), & Direct Injection (15PSI)
The Sellers immersion fired Ohio Special steam boiler meets Ohio regulation for unattended boilers.
The boiler is a horizontal, single pass, firetube boiler designed to burn natural gas. The unique burner assembly delivers pre-mixed air and gas through multiple nozzles. The air-gas mixture is ignited as it exits each flame retaining nozzle at high velocity The resulting flames are long and small in diameter. The flame from each of these nozzles is directed into a 2″ O.D. tube that is completely immersed in liquid. There is a separate tube for each flame with the same amount of heat going into each tube. These small diameter flames burn in the first half of the tube lengths. Therefore, the “fire shines“ on half of the heating surface in the single pass boiler — 50% of the total heating surface is radiant heating surface.
- One-pass fire tube steam boiler
- Combustion: Sealed
- Heat Exchanger: Steel tubes
- 10 – 800 HP (0.4 – 33.4mmBTU)
- NOx Rating: 30ppm
- Certifications: ASME “S” stamp, UL
- 1-year (parts)/ 5-year (shell)
- Fuels: Natural gas, propane
The TPS Immersion Fired 6201 Series of Fire Tube Low and High Pressure steam boilers (20-125 HP) is well known throughout the industry for its unique small footprint compact two-pass design and dual fuel burner technology. Available in both high pressure (up to 300psi) and low pressure steam, the two pass immersion fire tube design delivers premixed air and gas through multiple burner nozzles. A corresponding “fire tube”, completely immersed in liquid, is aligned with the nozzle head inside the combustion chamber. Upon combustion, the nozzles generate a focused, high velocity flame which radiates down the center of each tube.
The reason a customer might prefer one of our two-pass fire tube boilers instead of a single-pass boiler is that our two-pass boiler systems are designed explicitly for tighter space constraints. This optimal piece of equipment offers the small footprint application capacity you need while still providing Sellers-level quality.
- Style: Two-Pass For Small Footprint Applications
- Burner: Sellers Multi Flame
- Size: 20 – 125 HP (.8 – 5.2mmBTU)
- Burner Operation: On/Off w/ Pilot Hold
- Emission Rating: 30 & 20 ppm NOx
- Certifications: ASME
- Warranty: 10-Year (Shell) / 5-Year (Burner) / 1.5-Year (Parts)
- Fuels: Natural Gas & Propane
- Application: Steam (15-150 PSI) & Hot Water
Ygnis fire tube boilers are used exclusively for oil burning applications. Even though this design has a more limited applicability than our single-pass & two-pass fire tube boilers, Sellers is committed to providing a boiler for every specific need our customers face.
Available in both high pressure and low pressure steam, this particular shell design overcomes thermal shock problems common to other multi-pass boilers. Thermal stress is greatly reduced because of two unique features of the furnace: the larger diameter, shorter furnace produces less thermal expansion than a furnace of an ordinary boiler; and the furnace end is supported by stays which are attached to the rear tube sheet. Tube sheet fatigue failures are eliminated because shear stress between the furnace and the rear tube sheet is greatly reduced.
- Style: Three-Pass
- Burner: Gun Burner; multiple vendor options
- Size: 20 – 300 HP (.8 – 12.5mmBTU)
- Burner Operation: On/Off & Modulation
- Emission Rating: 30 ppm NOx
- Certifications: ASME
- Warranty: 3-Year (Shell) / 1.5-Year (Parts)
- Fuels: #2 Oil
- Application: Steam (15-150 PSI) & Hot Water
