Direct-fired, gas-fueled heater

Abstract

A direct-fired, gas-fueled heater for greenhouse use. The heater has a base with an airflow assembly disposed within the housing and configured so as to draw a flow of ambient air into the heater through the air inlet matrix, to circulate airflows within the housing, and to direct heated air out of the heater through an air housing exit. Also disposed within the housing is a heat chamber, the heat chamber including an outer wrapper, an upper insert and a lower insert. The lower insert has a lower insert slot having a lower insert slot area and is configured to allow passage of a quenching airflow therethrough to join and mix with a combustion discharge and dilution airflows circulated within the heater. Reduced emissions of certain combustion byproducts are realized.

1 . A direct-fired, gas-fueled heater, comprising: 
 a base having an air inlet matrix through which ambient air enters the heater; a housing mounted to the base, the housing being comprised of an outer casing, at least one door, and an air housing exit; an airflow assembly disposed within the housing and configured so as to draw a flow of ambient air into the heater through the air inlet matrix, to circulate the flow of ambient air as dilution airflows, a primary combustion airflow, and a quenching airflow within the housing, and to a direct a combustion discharge stream out of the heater through the air housing exit; a heat chamber disposed within the housing, the heat chamber being comprised of an outer wrapper, an upper insert and a lower insert, the two inserts being mounted in spaced relationship to define a heat chamber inlet; and a burner disposed within the heat chamber inlet, the burner having a discharge port configured with at least one discharge slot from which a combustion discharge emanates and a burner inlet, the burner being attached in spaced relationship to the base to allow a gaseous fuel and the primary combustion airflow to enter the burner through the burner inlet;    wherein the lower insert further comprises at least one lower insert slot sized and configured to allow passage of the quenching airflow therethrough to join and mix with the combustion discharge and the dilution airflows to form the combustion discharge stream.    
     
     
         2 . The heater of  claim 1 , wherein the heater is adapted to receive gaseous fuel into the burner inlet at a plurality of pressures from an external gaseous fuel supply.  
     
     
         3 . The heater of  claim 1 , wherein the heater is adapted to receive gaseous fuel into the burner inlet at a lower pressure from an external gaseous fuel supply.  
     
     
         4 . The heater of  claim 1 , wherein the airflow assembly is mounted to the lower insert in spaced relationship from the outer wrapper, the airflow assembly comprising: 
 a fan motor having a shaft, a motor mount, a fan wheel attached to the shaft, an inner scroll disposed between two end panels, the end panels each having an entrance, one entrance facing the heat chamber and being configured to receive the combustion discharge stream and the other entrance facing away from the heat chamber and being configured to receive the fan wheel within the inner scroll, the inner scroll and the two end panels cooperating to define a combustion discharge stream opening that is aligned with the air housing exit when the airflow assembly is mounted within the housing.    
     
     
         5 . The heater of a  claim 4 , further comprising a gas control assembly adapted for connection to the gaseous fuel supply, the gas control assembly being comprised of: 
 a pressure regulator through which gaseous fuel enters the gas control assembly; a manual shutoff valve; a sediment trap; a gas control valve; a burner manifold having a burner orifice.    
     
     
         6 . The heater of  claim 5 , wherein the burner orifice has a burner orifice area and the inlet has a inlet area, and the lower insert slot has a slot area, and the inlet matrix has an inlet matrix area.  
     
     
         7 . The heater of  claim 6 , wherein gaseous fuel is propane, the burner orifice has a burner orifice area of about 0.00013 in 2  per 1000 BTUH to about 0.00014 in 2  per 1000 BTUH; the inlet has an inlet area of about 0.9 in 2  per 1000 BTUH to about 1.2 in 2  per 1000 BTUH ; the lower insert slot has a slot area of about 0.28 in 2  per 1000 BTUH to about 0.31 in 2  per 1000 BTUH, and the inlet matrix has an inlet matrix area of between about 0.008 CFM per BTUH to about 0.009 CFM per BTUH.  
     
     
         8 . The heater of  claim 6 , wherein gaseous fuel is natural gas, the burner orifice has a burner orifice area of about 0.00025 in 2  per 1000 BTUH to about 0.00027 in 2  per 1000 BTUH; the inlet has an inlet area of about 0.9 in 2  per 1000 BTUH to about 1.2 in 2  per 1000 BTUH ; the lower insert slot has a slot area of about 0.28 in 2  per 1000 BTUH to about 0.31 in 2  per 1000 BTUH, and the inlet matrix has an inlet matrix area of between about 0.008 CFM per BTUH to about 0.009 CFM per BTUH.  
     
     
         9 . The heater of  claim 1 , wherein the airflow assembly is mounted in spaced relationship from the outlet of the heat chamber, the space between the airflow assembly and the heat chamber exit defining a mixing zone where dilution airflows, combustion discharge and quenching air flows are intermingled to begin forming the combustion discharge stream.  
     
     
         10 . The heater of  claim 9 , further comprising a gas control assembly adapted for connection to the gaseous fuel supply, the gas control assembly being comprised of: 
 a pressure regulator through which gaseous fuel enters the gas control assembly; a manual shutoff valve; a sediment trap; a gas control valve; a burner manifold having a burner orifice.    
     
     
         11 . The heater of  claim 10 , wherein the burner orifice has a burner orifice area and the inlet has a inlet area, and the lower insert slot has a slot area, and the inlet matrix has an inlet matrix area.  
     
     
         12 . The heater of  claim 11 , wherein gaseous fuel is propane, the burner orifice has a burner orifice area of about 0.00013 in 2  per 1000 BTUH to about 0.00014 in 2  per 1000 BTUH; the inlet has an inlet area of about 0.9 in 2  per 1000 BTUH to about 1.2 in 2  per 1000 BTUH ; the lower insert slot has a slot area of about 0.28 in 2  per 1000 BTUH to about 0.31 in 2  per 1000 BTUH, and the inlet matrix has an inlet matrix area of between about 0.008 CFM per BTUH to about 0.009 CFM per BTUH.  
     
     
         13 . The heater of  claim 11 , wherein gaseous fuel is natural gas, the burner orifice has a burner orifice area of about 0.00025 in 2  per 1000 BTUH to about 0.00027 in 2  per 1000 BTUH; the inlet has an inlet area of about 0.9 in 2  per 1000 BTUH to about 1.2 in 2  per 1000 BTUH ; the lower insert slot has a slot area of about 0.28 in 2  per 1000 BTUH to about 0.31 in 2  per 1000 BTUH, and the inlet matrix has an inlet matrix area of between about 0.008 CFM per BTUH to about 0.009 CFM per BTUH.  
     
     
         14 . The heater of any one of claims  1 - 13 , the heater further comprising an electronic controller for regulation of heater operational parameters.  
     
     
         15 . The heater of any one of claims  1 - 13 , the heater further comprising a control box, the control box comprising a panel, an ignition controller, a transformer, a power cord, and a harness.  
     
     
         16 . The heater of  claim 15 , wherein the control box is in electronic communication with one or more components selected from the group consisting of the gas control valve, fan motor, an air proving switch, an igniter, a temperature limit switch, a fan motor switch, a shutter assembly, and an exhaust fan motor.  
     
     
         17 . The heater of  claim 1 , wherein the heater is mounted within an enclosed structure.  
     
     
         18 . The heater of  claim 1 , wherein the heater is mounted exterior to an enclosed structure.  
     
     
         19 . The heater of  claim 17  or  18 , wherein the enclosed structure further comprises a shutter assembly.  
     
     
         20 . The heater of  claim 19 , wherein the shutter assembly is motor actuated.  
     
     
         21 . The heater of  claim 17 , wherein the enclosed structure further comprises an exhaust fan.