Each set of tubes that hot combustion flue gas travels through before making a turn within the boiler, is considered a "pass." A four-pass boiler design consists of four sets of horizontal tubes, with the stack outlet at the front of the vessel. A downdraft design keeps the cooler water from having an effect on the hot surfaces within the boiler. 4-pass boilers leverage natural draft operation which allows cool water to contact the hottest part of the boiler.
Generally speaking, a 4 pass boiler provides more opportunities for hot gasses to transfer heat to the water in a boiler and operate more efficiently (yielding a higher overall heat-transfer coefficient).
4 pass firetube boilers offer:
- maximized heat transfer
- minimal refractory
- high steam/water storage
- effective handling of wide load demands
Trust the firetube boiler experts at IB&M
Industrial Boiler & Mechanical proudly sells new 4 pass firetube boilers manufactured by Johnston Boiler Company. We are also authorized to serivce and repair 4 pass boilers from other manufacturers as well, both on-site and in-house at our facility in Chattanooga, TN.
In addition to an in-stock inventory of used 4 pass boilers, we offer firetube boiler customization to meet any specification. Firetube boilers can be shipped individually, on a packaged skid, or as complete "boiler in a box" solution. And as as a fully licensed General Contractor with divisions dedicated to every aspect of the boiler room inside and out, we are able to provide system design and engineering, concrete work, electrical services, process piping, and more to provide a total steam plant solution.
For questions or more information on selecting a new or used 4 pass firetube boiler, contact IB&M today at (855) 753-BOILER. We provide annual equipment maintenance contracts and have on-hand emergency rental boilers too.