Direct-fired heater

A direct-fired heater for outputting heated air, the direct-fired heater comprising:

• a) a cylindrical housing having an inlet end and an outlet end, the cylindrical housing being defined by a longitudinal dimension and a circular diameter, the cylindrical housing also having a topside and an underside;
• b) a combustion system mounted within said housing proximate the longitudinal midpoint of said cylindrical housing, the combustion system having
• a circularly-shaped burner tube having a plurality of gas exit holes on one side and a means for feeding a controlled volume of gas thereto, said burner tube having a set diameter;
• a first conical frustum section having a pre-determined first pattern of orifice ports, the first conical frustum having a basal end having a diameter proximate the diameter of the burner tube and a smaller diameter distal end, the basal end of the first conical frustum section being attached to the burner tube at a position radially inward from said gas exit holes;
• and
• a second conical frustum section having a pre-determined second pattern of orifice ports, said second conical frustum section having a basal end and a larger diameter distal end, said basal end of the second conical frustum section having a diameter proximate the diameter of the burner tube, said basal end of the second conical frustum section attached to the burner tube at a position radially outward from said gas exit holes;
• c) a motor mounted within said housing closer to said inlet end and connected to a propeller for drawing air into said inlet, through the housing and out of the outlet;
• and
• d) a control means including a thermostat for adjusting the volume of gas delivered to said burner tube and for adjusting the speed of the motor, thereby variably adjusting the heat output of the heater.