Air preheating system for continuous fired furnace

A system for preheating combustion air being fed to a continuous fired furnace by means of the high temperature waste gases being exhausted from said furnace, said system comprising:

• a pair of parallel vertically extending first regenerators, each having upper and lower ends,
• an ambient air inlet and a waste gas exhaust stack adjacent to the upper ends of said first regenerators,
• a first reversing valve arranged at the upper ends of said first regenerators, said first reversing valve being alternately adjustable to connect said ambient air inlet with either one of the upper ends of said first regenerators while simultaneously connecting the upper end of the other of said first regenerators to said exhaust stack,
• a pair of parallel vertically extending second regenerators, each having upper and lower ends,
• conduit means for connecting the lower ends of said first regenerators to the lower ends of said second regenerators,
• a waste gas inlet and a preheated combustion air outlet arranged adjacent to the upper ends of said second regenerators, and a
• second reversing valve arranged at the upper ends of said second regenerators, said second reversing valve being alternately adjustable to connect said waste gas inlet with either one of the upper ends of said second regenerators while simultaneously connecting the upper end of the other of said second regenerators to said preheated combustion air outlet.