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A duct through which the products of combustion are transported from the furnace to the stack; usually applied in steam boilers.
1. The duct or pipe connecting the exhaust-gas discharge from a boiler furnace, or other fuel-burning equipment, to a stack.
2. A breeching fitting.
breeching fitting, breech fitting, breeching
A Y-shaped symmetrical pipe fitting in which the flow in two parallel pipes is united in one pipe.