Compact high-efficiency air heater

An air heater, comprising:

• a burner for burning a combustible fuel to provide flue gases, said burner including a cylindrical chamber having a slot formed along its length;
• a combustion chamber surrounding said burner;
• a heat exchanger defining a plurality of flue gas passages and air passages and further defining an air inlet side, an air outlet side, a flue gas inlet side and a flue gas outlet side;
• wherein said slot is oriented in a pre-determined angle with respect to said flue gas inlet side;
• and
• wherein said slot is oriented to provide said flue gases with an initial direction G having both a horizontal component GH and a vertical component GV;
• and
• wherein said horizontal component GH directs said flue gases against said surface of said combustion chamber.

An air heater, comprising:

• a burner for burning a combustible fuel to provide flue gases;
• a combustion chamber surrounding said burner;
• a heat exchanger defining a plurality of flue gas passages and air passages and further defining an air inlet side, an air outlet side, a flue gas inlet side and a flue gas outlet side, wherein said combustion chamber communicates with such flue gas inlet side of said heat exchanger to direct said flue gases through said flue passages;
• and
• an air distribution plate located along said air inlet side of said heat exchanger, and
• wherein said air distribution plate includes a plurality of apertures decreasing in size in a direction extending from said flue gas inlet side to said flue gas outlet side whereby the mass flow of air through said heat exchanger is decreased in the direction extending from said flue gas inlet side to said flue gas outlet side thereby reducing the temperature gradient exhibited along the air outlet side of said heat exchanger.

An air heater, comprising:

• a burner for burning a combustible fuel to provide flue gases;
• a combustion chamber surrounding said burner;
• a heat exchanger defining a plurality of flue gas passages and air passages and further defining an air inlet side, an air outlet side, a flue gas inlet side and a flue gas outlet side, wherein said combustion chamber communicates with such flue gas inlet side of said heat exchanger to direct said flue gases through said flue passages;
• and
• a comfort regulation control system having a first temperature sensor for monitoring room temperature at a working elevation and a second temperature sensor for monitoring room temperature at a second elevated elevation, said comfort regulation control system including:
• a first control loop for switching said burner between an on condition and an off condition and for regulating the output of said burner between a preset minimum output and a preset maximum output;
• a second control loop for switching said fan between an on condition and an off condition for regulating said fan between a low setting and a high setting;
• and
• a third anti-stratification control loop for switching said fan between said off condition and said low setting when said burner is in said off condition whereby both the heating of the room and anti-stratification of the air in the room is accomplished.

An air heater, comprising:

• a burner for burning a combustible fuel to provide flue gases;
• a combustion chamber surrounding said burner;
• a heat exchanger defining a plurality of flue gas passages and air passages and further defining an air inlet side, an air outlet side, a flue gas inlet side and a flue gas outlet side, and wherein said combustion chamber communicates with said flue gas inlet side of said heat exchanger to direct said flue gases through said flue passages;
• at least one bypass channel which directs air flow across at least one surface of said combustion chamber to remove heat from said surface;
• a plurality of heat shields;
• and
• wherein said heat exchanger includes an assembly of stacked corrugated plates, each of said plates includes opposing outer flanges about the periphery thereof;
• and
• wherein preselected flanges of said stacked corrugated plates are brazed together to define said alternating flue gas and air passage;
• and
• wherein said heat shields include an interior protective zone for surrounding said brazed flanges of said heat exchanger along said flue gas inlet side of said heat exchanger.