초록 ▼

Flue gases containing crackable and combustible volatiles e.g. from a wood-burning stove are passed through a catalytic combustor having two spaced catalytic units each having small longitudinally extending catalytic flow passages. Air supplied into a chamber between the two units supports after-com

Flue gases containing crackable and combustible volatiles e.g. from a wood-burning stove are passed through a catalytic combustor having two spaced catalytic units each having small longitudinally extending catalytic flow passages. Air supplied into a chamber between the two units supports after-combustion of combustible volatiles in the downstream catalytic unit. Some pre-cracking and combustion takes place in the upstream catalytic unit, which serves as a gas collimator and disallows any flow of air from the intermediate chamber into the fire box of the stove, whereby combustion in the fire box can be closely controlled to increase production of combustible volatiles. Each unit may have flow passages which decrease in cross-sectional size and increase in length toward the central portion of the unit, thus encouraging uniformity of flow of the flue gases and of the catalytic reaction over the entire cross section of each unit. The units are surrounded by an air jacket into which air is supplied at one end, and the air is distributed uniformly around the periphery of the intermediate chamber. Each unit has a central bypass opening and a temperature responsive valve which closes the bypass opening when the catalytic unit reaches its threshold temperature of operation. A reflector, preferably with a curved reflective face, reflects radiant heat to the downstream fuel of the combustor, and an exterior heat exchange jacket transfers heat to the surroundings from the hot gases exiting from the combustor. A flame-arresting screen is spaced between the fire box and the combustor to prevent diffusion flames originating in the fire box from lapping on the catalytic flow passages.

대표청구항 ▼

In combination: a solid fuel burning stove having a firebox and a flue aperture; a heat exchanger jacket connected to the flue aperture and having a tubular inner wall and a tubular outer wall spaced outwardly therefrom and defining an air space therewith; a catalytic combustor unit disposed in the

In combination: a solid fuel burning stove having a firebox and a flue aperture; a heat exchanger jacket connected to the flue aperture and having a tubular inner wall and a tubular outer wall spaced outwardly therefrom and defining an air space therewith; a catalytic combustor unit disposed in the heat exchanger jacket comprising means for maintaining approximately true pyrolysis in the firebox, including a first catalytic unit and a second catalytic unit spaced longitudinally downstream from the first unit and defining therewith a chamber bounded by an intermediate portion of the inner wall of the heat exchanger jacket, each catalytic unit comprising longitudinally extending walls defining a multitude of small tubular flow passages extending generally longitudinally of the heat exchanger jacket and supporting a catalyst for promoting cracking of hydrocarbons and combustion of carbon monoxide and carbon particles, an air inlet conduit communicating between the surroundings and the air space in the heat exchanger jacket, for introducing secondary combustion air into the air space; and air inlet ports through said portion of the inner wall of the heat exchanger jacket, the ports directing the secondary combustion air non-radially into said chamber, whereby a vortex is created within the chamber to promote homogeneous mixing of the secondary combustion air with the gases passing through the combustor unit; means for efficient warming of said catalytic units to operating temperature comprising each catalystic unit being generally annular in shape and having its outer surface in heat exchange contact with the inner wall of the heat exchanger jacket and its inner surface defining a central gas bypass opening, a valve member associated with each bypass opening, temperature responsive control means responsive to the temperature of gas issuing from the combustor unit and moving each valve member toward a position fully closing each bypass opening when the temperature exceeds a predetermined limit and moving each valve member toward a position relatively opening each bypass opening when the temperature falls below a predetermined limit; means providing adequate residence of gases in said second unit comprising said second unit having its tubular flow passages substantially longer than the flow passages of the first unit; a casing surrounding the heat exchanger jacket, for receiving hot gases issuing from the second catalytic unit, and having an outlet to a stack; and a baffle disposed in the casing between its outlet and the second catalytic unit, the baffle directing said hot gases in heat exchange relationship over the outer side of the outer wall of the heat exchanger jacket.