Adjustable Primary Air Supply for Wood Burning Device

Abstract

An improved adjustable primary air supply for wood burning device comprises a base plate having an opening from where primary air enters a firebox. A gate rotationally attached to the base plate by way of a mechanical fastener; a slider with guiding means sliding within an inclined slot; the slider comprised of a contact point which makes contact with the gate for adjustments. A first thermostatic bimetal blade reacting to heat by displacing the gate so that the gate closes the opening; and a means to move the slider and push the gate fully open. The improvement comprising a first stopper member located on the base plate adjacent the opening and adapted to stop the movement of the gate and thereby prevent the gate from completely covering the opening, and a second thermostatic bimetal blade attached to the gate and adapted to react to heat by displacing the gate from the base plate so that the gate can move over the first stopper member such that the gate can continue to cover the opening until the gate contacts the slider contact point.

1 . In an adjustable primary air supply for a wood burning device comprising a base plate having an opening from where primary air enters a firebox; a gate rotationally attached to said base plate by way of a mechanical fastener; a slider with guiding means sliding within an inclined slot; said slider comprised of a contact point which makes contact with said gate for adjustments; a first thermostatic bimetal blade reacting to heat by displacing said gate so that said gate closes said opening; and a means to move said slider and push said gate fully open; the improvement comprising a first stopper member located on said base plate adjacent said opening and adapted to stop the movement of said gate and thereby prevent said gate from completely covering said opening; and a second thermostatic bimetal blade attached to said gate and adapted to react to heat by displacing said gate from said base plate so that said gate can move over said first stopper member such that said gate can continue to cover said opening until said gate contacts said slider contact point. 
     
     
         2 . The adjustable primary air supply improvement of  claim 1 , further including a safety mechanism comprising a bracket member attached to a said first bimetal blade; a pivot rod attached between said base plate and said bracket member and adapted to allow said first bimetal blade to pivot there around; a second stopper member adapted to stop said bimetal blade from pivoting past a predetermined point; and a spring member attached at one end to said bracket member and at an opposite end to a point on said base plate at a distance therefrom and is adapted to hold said bracket against said second stopper member and to prevent said bimetal blade from deforming. 
     
     
         3 . An adjustable primary air supply for a wood burning device as in  claim 1 , and having the following method of operation: when starting a fire, said gate is opened to bring in as much air as possible; said first bimetal blade bends as the temperature rises; said first bimetal blade pushes said gate partially over said opening until it hits said first stopper member; said second bimetal blade bends as the temperature continues to increase until the space created between said blade and said base plate is great enough to allow said gate to overpass said first stopper member and continue to further cover said opening until said blade contacts said slider contact point and stops; and when said first and second bimetal blades gets colder, they retract to their original configurations but said gate stays at the same position. 
     
     
         4 . The adjustable primary air supply for a wood burning device as in  claim 1 , wherein said means to move said slider and push said gate fully open includes a key; said key being turned to rotate a cog wheel which engages into a track which includes a plurality of holes. 
     
     
         5 . The adjustable primary air supply for a wood burning device as in  claim 1 , wherein the amount of said primary air is varied by the position of said slider. 
     
     
         6 . The adjustable primary air supply for a wood burning device as in  claim 3 , wherein the method of operation further includes: at minimum burn rate, said gate being completely closed by said first thermostatic bimetal blade, but said gate being raised by said second thermostatic bimetal blade thereby allowing a small amount of primary air to still enter said firebox; by the end of the burning cycle, as the temperature drops, said second thermostatic bimetal blade returns to a bent shape which allows said gate to close said opening completely. 
     
     
         7 . The adjustable primary air supply for a wood burning device as in  claim 4 , wherein said gate is adapted to be pushed by said key when said key is pushed inwardly. 
     
     
         8 . The adjustable primary air supply for a wood burning device as in  claim 1 , wherein said first stopper member is an angled tab formed and bent from the material of said base plate. 
     
     
         9 . The adjustable primary air supply for a wood burning device as in  claim 2 , wherein said second stopper member is generally shaped as a hook member formed integrally with and bent perpendicular from said base plate. 
     
     
         10 . The adjustable primary air supply for a wood burning device as in  claim 2 , wherein said point on said base plate includes a base spring bracket adapted to connect to said opposite end of said spring member.