Abstract: A stove for burning fuel in which secondary air is introduced and mixed with the products of combustion in a firebox with primary air, the secondary air being kept from the firebox by a gravity-induced downward movement owing to the greater density of the secondary air-combustion products mixture as compared with the products of combustion per se.

Abstract: A combustor including a combustion chamber having two paths for removing combustion exhaust gases, a valve in one path, and means to provide, when the valve is in a closed position, pressure at a downstream side of the valve higher than the pressure inside the combustion chamber to prevent leakage of combustion gases from the combustion chamber through the valve.

Abstract: Apparatus supporting a catalytic converter for a burner comprising a support including an opening for passage of exhaust gases therethrough, a catalytic converter mounted on the support for movement into and out of an operating position adjacent to the opening to receive the exhaust gases, and means extending from the support for causing the catalytic converter to be moved into and out of the operating position.

Abstract: Apparatus for supporting a catalytic converter for a burner including a housing having an opening for directing the exhaust gases to a catalyst region and a by-pass opening permitting the exhaust gases to by-pass the catalyst region, a baffle positioned over the catalyst region and having a groove formed in it and a tab extending from one end and adjacent to the groove, a closure movably mounted to open and close the by-pass opening, and a control rod slidably and pivotally mounted within the groove and having one end connected to the closure to open and close the by-pass opening by pivoting of the rod, the rod being lockably engageable by the tab by longitudinal displacement of the rod when in a pivotal position corresponding to closing of the by-pass opening, and having handle means extending from the other end for permitting pivoting and longitudinal displacement of the rod.