For example, the hot
return flue gases in a reverse flame chamber increase the flame temperature, thereby limiting the level of NOx reduction that is achieved.
There he worked on an 1895 16 hp (some believe it to be an 18 hp) Case
return flue, center-crank steam engine.
I read with interest the story in the June 2014 issue of Farm Collector, pages 30-31, pertaining to a Case center-crank
return flue steam engine.
The report also boasted of the design of another product, the Stillwater engine: "The engine's
return flue, being placed above the lines of the crown sheet, ensures a depth of several inches of water over it, so that it is never exposed in ascending or descending hills, and this, with the arch-like shape of the crown sheet, makes it so strong and safe that not a single instance of collapse or sagging of the crown-sheet has occurred in any one of the many hundreds of these boilers that have been and are now in use."
He claimed to have gained a 40 percent increase in fuel efficiency with the
return flue compared to the straight-through flue heating system.
The company's owner, Edward Huber, earned more than 100 patents on farm machinery, including inventing the return flue boiler-type steam engine.
in addition to the first-ever return flue boiler-type steam traction engine, he invented Huber skid steam engines, Huber bean, pea and rice threshers, and much more.
In 1898, Aultman & Taylor offered Eureka Jr., Eureka and Hercules engines, as well as the straw-burning,
return flue Cyclone and Columbia Jr.
Sometime between 1885 and 1900, the Phoenix
return flue engine and the Star engine also appeared in the Aultman line-up.