Standing pilot furnace with vented vestibule

Abstract

An induced draft, fuel-fired furnace having a heat exchanger with an inlet and an outlet includes a vent having an inlet, a burner, and a vented vestibule in fluid communication with the vent. A blower has an inlet in fluid communication with the heat exchanger outlet, and an outlet disposed at the inlet of the vent. The blower outlet has a cross-sectional area smaller than the vent inlet. The vent inlet and blower outlet define a vent inlet opening. A drafthood formed with an inlet is disposed in the vestibule and forms a plenum in fluid communication with the vent inlet opening. A source of combustion products is disposed in the furnace such that combustion products produced thereby are in fluid communication with the drafthood inlet and vent inlet opening. The source of combustion products includes either a standing pilot or electronic ignitor for igniting fuel operably discharged from the burner.

What is claimed is:  
     
       1. An induced draft, fuel-fired furnace having a heat exchanger with an inlet and an outlet, said furnace comprising: 
       a vent having an inlet;  
       a burner;  
       a vented vestibule in fluid communication with said vent;  
       a blower having an inlet in fluid communication with the heat exchanger outlet, and an outlet disposed at the inlet of said vent, said blower outlet having a cross-sectional area smaller than said vent inlet, said vent inlet and blower outlet defining a vent inlet opening; and  
       a standing pilot disposed in said furnace such that combustion products produced thereby are in fluid communication with said vent inlet opening, said standing pilot adapted to ignite fuel operably discharged from said burner.  
     
     
       2. The induced draft, fuel-fired furnace of claim  1 , further comprising a drafthood disposed in said vestibule and forming a plenum in fluid communication with said vent inlet opening, said drafthood including an undersurface disposed adjacent said blower outlet and extending immediately adjacent to a panel of the furnace, the panel having at least one aperture formed therein, said undersurface formed with an inlet adapted to receive combustion gases from said standing pilot, and a blocked vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent. 
     
     
       3. The furnace of claim  1  wherein said vent inlet opening is adapted to allow a draft condition in said vestibule. 
     
     
       4. The induced draft, fuel-fired furnace of claim  2  further comprising a gas valve operably supplying fuel to said burner and pilot light, said blocked vent detecting means adapted to operably control said gas valve. 
     
     
       5. The induced draft, fuel-fired furnace of claim  4  wherein said blocked vent detecting means is a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent. 
     
     
       6. The induced draft, fuel-fired furnace of claim  4  wherein said blocked vent detecting means is a pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent. 
     
     
       7. The induced draft, fuel-fired furnace of claim  1  wherein said blower is a centrifugal blower. 
     
     
       8. The induced draft, fuel-fired furnace of claim  1  wherein said burner and standing pilot are disposed near the bottom of said vestibule, and further comprising a horizontal wall disposed above said burner and standing pilot, said horizontal wall formed with an opening allowing combustion gases from said standing pilot to flow therethrough. 
     
     
       9. The induced draft, fuel-fired furnace of claim  1  wherein said burner and standing pilot are disposed near the bottom of said vestibule, and further comprising two offset horizontal walls forming an opening allowing combustion gases from said standing pilot to flow through said opening between said two horizontal walls. 
     
     
       10. The induced draft, fuel-fired furnace of claim  9  wherein one wall of said vestibule is a removable louvered panel, said louvers  louvered panel providing a vent and  source of ventilation air from the ambient environment and allowing updraft through said vestibule and dilution of exhaust gases within said vestibule and vent. 
     
     
       11. The induced draft, fuel-fired furnace of claim  1  wherein said vent inlet and blower outlet each have a generally circular shape, said blower outlet located in or closely adjacent said vent inlet, said vent inlet opening defined by the annular area between the periphery of said vent inlet and blower outlet. 
     
     
       12. The induced draft, fuel-fired furnace comprising: 
       a heat exchanger having an inlet and an outlet;  
       a vent including an inlet and a venturi section;  
       a burner;  
       a vented vestibule in fluid communication with said vent;  
       a blower having an inlet in fluid communication with said heat exchanger outlet and an outlet in fluid communication with said vent inlet; and  
       a standing pilot disposed in said furnace such that combustion products provided thereby are in fluid communication with said venturi section, said standing pilot adapted to ignite fuel operably discharged from said burner.  
     
     
       13. The furnace of claim  12  wherein said venturi section is adapted to provide a draft condition in said vestibule. 
     
     
       14. The induced draft, fuel-fired furnace of claim  12 , wherein said blower outlet has a generally circular cross-sectional area smaller than and centrally located at said vent inlet, the annular area between the vent inlet and blower outlet defined said venturi section. 
     
     
       15. An induced draft, fuel-fired furnace, comprising: 
       a heat exchanger having an inlet and an outlet;  
       a vent having an inlet;  
       means for providing an area of lower pressure, said providing means defined at least in part by said vent;  
       a vented vestibule;  
       a burner disposed within said vestibule and in fluid communication with said heat exchanger inlet and said area of lower pressure;  
       an induced draft blower having an inlet disposed in fluid communication with said heat exchanger outlet and an outlet disposed in fluid communication with the inlet of said vent; and  
       means for igniting fuel operably discharged from said burner.  
     
     
       16. The furnace of claim  15 further comprising a standing pilot disposed in said furnace, said vent including a venturi section wherein said venturi section allows products of combustion from said standing pilot to flow therethrough into said vent and further allows products of combustion exhausted into said vent from said induced draft blower to backflow into said vestibule during a blocked vent condition. 
     
     
       17. The furnace of claim  15 wherein said vent includes a venturi section, said furnace further comprising a standing pilot disposed in said furnace and a drafthood disposed adjacent said blower outlet and in fluid communication with said venturi section, said drafthood having an undersurface with an opening formed therein for allowing combustion products from said standing pilot to flow therethrough, said drafthood including a temperature sensor to detect hot exhaust gases exhausted into said drafthood during said blocked vent condition. 
     
     
       18. The furnace of claim  17 , further comprising a valve operably supplying fuel to said burner and standing pilot, said temperature sensor adapted to operably control said valve and close said valve during a blocked vent condition. 
     
     
       19. The furnace of claim  15 whereinfurther comprising a standing pilot disposed in said furnace, said vestibule isbeing partially defined by a vertical wall at the outlet of said burner and a housing fixed to said vertical wall which is disposed above said standing pilot and said burner, said generally horizontal wall forming asaid housing adapted to have said valve, burner and standing pilot light  fixed thereto, said housing including a generally horizontal wall having an opening formed therein for allowing combustion products produced by said standing pilot to draft upwards therethrough. 
     
     
       20. The furnace of claim  15 whereinfurther comprising a standing pilot disposed in said furnace, said vestibule isbeing defined in part by a vertical wall disposed at the outlet of said burner and a housing fixed to said vertical wall which is disposed above said standing pilot and said burner, said housing adapted to have said valve, burner and standing pilot fixed thereto, said housing including two generally horizontal members disposed offset to each other and forming an opening therebetween for allowing combustion products produced by said standing pilot to draft upwards therethrough. 
     
     
       21. The induced draft, fuel-fired furnace of claim  15 , wherein said igniting means is a standing pilot light. 
     
     
       22. The induced draft, fuel-fired furnace of claim  15 , wherein said igniting means is an electronic ignitor. 
     
     
       23. The induced draft, fuel-fired furnace of claim  15 , wherein said blower outlet has a cross-sectional area smaller than said vent inlet, said blower outlet and vent inlet defining said area of lower pressure. 
     
     
       24. An induced draft, fuel-fired furnace, comprising: 
       a vent having an inlet;  
       a vented vestibule disposed in fluid communication with said vent, said vestibule comprising a plurality of panels;  
       a blower having an inlet in fluid communication with the heat exchanger outlet  said vestibule, and an outlet disposed at the inlet of said vent;  
       a drafthood disposed in said vestibule, said drafthood forming a plenum in fluid communication with said vent and including an inlet , said drafthood in fluid communication with an aperture formed in one of said vented vestibule panels, said drafthood including an undersurface formed with an inlet, and a blocked vented  vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent;  
       a burner disposed in said furnace and in fluid communication with said drafthood inlet; and  
       means for igniting fuel operably discharged from said burner.  
     
     
       25. The induced draft, fuel-fired furnace of claim  24  wherein said igniting means is a standing pilot light. 
     
     
       26. The induced draft, fuel-fired furnace of claim  24  wherein said igniting means is an electronic ignitor. 
     
     
       27. An induced draft, fuel- fired furnace, comprising:    
       
         a heat exchanger having an inlet and an outlet;  
       
       
         a vent including an inlet and a venturi section;  
       
       
         a burner;  
       
       
         ignition means for igniting fuel operatively discharged from said burner;  
       
       
         a blower having an inlet in fluid communication with said heat exchanger outlet and an outlet in fluid communication with said vent inlet; and  
       
       
         drafthood means separating said ignition means from said vent, said drafthood means having a plurality of openings to allow fluid communication between said ignition means and said venturi section.  
       
     
     
       28. The induced draft, fuel- fired furnace of claim  27  further comprising a removable louvered panel adjacent said drafthood means, said louvered panel providing a source of ventilation air from the ambient environment and allowing updraft and dilution of exhaust gases within said vent.    
     
     
       29. The induced draft, fuel- fired furnace of claim  27  wherein said venturi section is adapted to allow a draft condition in said furnace.    
     
     
       30. The induced draft, fuel- fired furnace of claim  27  wherein said drafthood means is disposed in a vestibule of said furnace and forms a plenum in fluid communication with said vent inlet opening, and said drafthood means includes an undersurface disposed adjacent said blower outlet and extending immediately adjacent to a panel of the furnace.    
     
     
       31. The induced draft, fuel- fired furnace of claim  30  wherein said panel has at least one aperture, and said furnace further includes blocked vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent.    
     
     
       32. The induced draft, fuel- fired furnace of claim  31  wherein said blocked vent detecting means includes a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood means when a blocked exhaust gas flow condition exists in said vent.    
     
     
       33. The induced draft, fuel- fired furnace of claim  31  wherein said blocked vent detecting means is a pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood means when a blocked exhaust gas flow condition exists in said vent.    
     
     
       34. An induced draft, fuel- fired furnace comprising:    
       
         a heat exchanger having an inlet and an outlet;  
       
       
         a vent including an inlet and a venturi section;  
       
       
         a burner;  
       
       
         a blower having an inlet in fluid communication with said heat exchanger outlet and an outlet in fluid communication with said vent inlet; and  
       
       
         a drafthood in fluid communication with said vent, said drafthood disposed in a vestibule of said furnace and forming a plenum in fluid communication with said vent inlet opening, said drafthood including an undersurface disposed adjacent said blower outlet and extending immediately adjacent to a panel of the furnace.  
       
     
     
       35. The induced draft, fuel- fired furnace of claim  34  wherein the panel has at least one aperture, and said furnace further includes blocked vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent.    
     
     
       36. The induced draft, fuel- fired furnace of claim  35  wherein said blocked vent detecting means includes a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent.    
     
     
       37. The induced draft, fuel- fired furnace of claim  35  wherein said blocked vent detecting means is a pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent.    
     
     
       38. The induced draft, fuel- fired furnace of claim  34  wherein said panel is a removable louvered panel adjacent said drafthood, said louvered panel providing a source of ventilation air from the ambient environment and allowing updraft and dilution of exhaust gases within said vent.    
     
     
       39. The induced draft, fuel- fired furnace of claim  34  wherein said venturi section is adapted to allow a draft condition in said furnace.    
     
     
       40. An induced draft, fuel- fired furnace, comprising:    
       
         a heat exchanger having an inlet and an outlet;  
       
       
         a vent having an inlet;  
       
       
         low pressure means for providing an area of lower pressure, said low pressure means defined at least in part by said vent;  
       
       
         a burner disposed within a vestibule and in fluid communication with said heat exchanger inlet and said area of lower pressure;  
       
       
         ignition means for igniting fuel operatively discharged from said burner, said means disposed in said vestibule;  
       
       
         an induced draft blower having an inlet disposed in fluid communication with said heat exchanger outlet and an outlet disposed in fluid communication with the inlet of said vent; and  
       
       
         drafthood means disposed in said vestibule and separating said ignition means from said vent, said drafthood means having a plurality of openings to allow fluid communication between said ignition means and said low pressure means.  
       
     
     
       41. The induced draft, fuel- fired furnace of claim  40  further comprising a removable louvered panel adjacent said drafthood means, said louvered panel providing a source of ventilation air from the ambient environment and allowing updraft and dilution of exhaust gases within said vent.    
     
     
       42. The induced draft, fuel- fired furnace of claim  40  wherein said low pressure means is adapted to allow a draft condition in said furnace.    
     
     
       43. The induced draft, fuel- fired furnace of claim  40  wherein said drafthood means is disposed in a vestibule of said furnace and forms a plenum in fluid communication with said vent inlet opening, and said drafthood means includes an undersurface disposed adjacent said blower outlet and extending immediately adjacent to a panel of the furnace.    
     
     
       44. The induced draft, fuel- fired furnace of claim  43  wherein said panel has at least one aperture, and said furnace further includes blocked vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent.    
     
     
       45. The induced draft, fuel- fired furnace of claim  44  wherein said blocked vent detecting means includes a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood means when a blocked exhaust gas flow condition exists in said vent.    
     
     
       46. The induced draft, fuel- fired furnace of claim  44  wherein said blocked vent detecting means is a pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood means when a blocked exhaust gas flow condition exists in said vent.    
     
     
       47. An induced draft, fuel- fired furnace comprising:    
       
         a heat exchanger having an inlet and an outlet;  
       
       
         a vent having an inlet;  
       
       
         low pressure means for providing an area of lower pressure, said low pressure means defined at least in part by said vent;  
       
       
         a burner disposed within a vestibule and in fluid communication with said heat exchanger inlet and said area of lower pressure;  
       
       
         an induced draft blower having an inlet disposed in fluid communication with said heat exchanger outlet and an outlet disposed in fluid communication with the inlet of said vent; and  
       
       
         a drafthood in fluid communication with said vent, said drafthood including an undersurface disposed adjacent said blower outlet and extending immediately adjacent to a panel of the vestibule.  
       
     
     
       48. The induced draft, fuel- fired furnace of claim  47  wherein the panel has at least one aperture, and said furnace further includes blocked vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent.    
     
     
       49. The induced draft, fuel- fired furnace of claim  48  wherein said blocked vent detecting means includes a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent.    
     
     
       50. The induced draft, fuel- fired furnace of claim  48  wherein said blocked vent detecting means is a pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent.    
     
     
       51. The induced draft, fuel- fired furnace of claim  47  wherein said panel is a removable louvered panel adjacent said drafthood, said louvered panel providing a source of ventilation air from the ambient environment and allowing updraft and dilution of exhaust gases within said vent.    
     
     
       52. The induced draft, fuel- fired furnace of claim  47  wherein said venturi section is adapted to allow a draft condition in said furnace.    
     
     
       53. An induced draft, fuel- fired furnace, comprising:    
       
         a vent having an inlet;  
       
       
         a vented vestibule disposed in fluid communication with said vent, said vestibule comprising a plurality of panels;  
       
       
         a blower having an inlet in fluid communication with said vestibule, and an outlet disposed at the inlet of said vent;  
       
       
         a drafthood disposed in said vestibule, said drafthood forming a plenum in fluid communication with said vent, said drafthood in fluid communication with an aperture formed in one of said vented vestibule panels, said drafthood including an undersurface formed with an inlet;  
       
       
         a burner disposed in said furnace and in fluid communication with said drafthood inlet; and  
       
       
         igniting means for igniting fuel operably discharged from said burner.  
       
     
     
       54. The induced draft, fuel- fired furnace of claim  53  further comprising a removable louvered panel adjacent said drafthood, said louvered panel providing a source of ventilation air from the ambient environment and allowing updraft and dilution of exhaust gases within said vent.    
     
     
       55. The induced draft, fuel- fired furnace of claim  53  wherein said vent includes a venturi section adapted to allow a draft condition in said furnace.    
     
     
       56. The induced draft, fuel- fired furnace of claim  53  wherein said igniting means includes a standing pilot light.    
     
     
       57. The induced draft, fuel- fired furnace of claim  53  wherein said igniting means includes an electronic ignitor.    
     
     
       58. An induced draft, fuel- fired furnace, comprising:    
       
         a vent having an inlet;  
       
       
         a vented vestibule disposed in fluid communication with said vent, said vestibule comprising a plurality of panels;  
       
       
         a blower having an inlet in fluid communication with said vestibule, and an outlet disposed at the inlet of said vent;  
       
       
         a drafthood disposed in said vestibule, said drafthood forming a plenum in fluid communication with said vent, said drafthood in fluid communication with an aperture formed in one of said vestibule panels, said drafthood including an undersurface formed with an inlet;  
       
       
         a burner disposed in said furnace and in fluid communication with said drafthood inlet;  
       
       
         igniting means for igniting fuel operatively discharged from said burner; and  
       
       
         blocked vent detecting means adapted to detect a blocked exhaust gas flow condition in said vent, said blocked vent detecting means including a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent.  
       
     
     
       59. The induced draft, fuel- fired furnace of claim  58  wherein said blocked vent detecting means includes pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood when a blocked exhaust gas flow condition exists in said vent.    
     
     
       60. The induced draft, fuel- fired furnace of claim  58  further comprising a removable louvered panel adjacent said drafthood, said louvered panel providing a source of ventilation air from the ambient environment and allowing updraft and dilution of exhaust gases within said vent.    
     
     
       61. The induced draft, fuel- fired furnace of claim  58  wherein said vent includes a venturi section adapted to allow a draft condition in said furnace.    
     
     
       62. The induced draft, fuel- fired furnace of claim  58  wherein said igniting means includes a standing pilot light.    
     
     
       63. The induced draft, fuel- fired furnace of claim  58  wherein said igniting means includes an electronic ignitor.    
     
     
       64. An induced draft, fuel- fired furnace, comprising:    
       
         a heat exchanger having an inlet and an outlet;  
       
       
         a flue including an inlet and a venturi section;  
       
       
         a burner;  
       
       
         igniting means for igniting fuel operatively discharged from said burner, said igniting means producing combustion gases;  
       
         a blower having an inlet in fluid communication with said heat exchanger outlet and an outlet in fluid communication with said flue inlet, said blower having an operational mode and a non - operational mode;    
       
         a vent adjacent said igniting means, said vent providing a source of ventilation air; and  
       
         drafthood means positioned within said furnace and including a plurality of apertures to allow communication of said ventilation air from said vent to said flue and to create an updraft which draws said igniting means combustion gases from said igniting means through said drafthood apertures, into said venturi section, and to the outside environment through said flue during said non - operational mode of said blower.    
     
     
       65. The induced draft, fuel- fired furnace of claim  64 , further including a second vent adjacent said flue inlet, said second vent providing a source of dilution air and creating an updraft which draws ambient air through said second vent and into said venturi section to mix with, and dilute, said combustion gases exiting from said heat exchanger outlet during said operational mode of said blower.    
     
     
       66. The induced draft, fuel- fired furnace of claim  64  wherein said furnace further includes blocked flue detecting means adapted to detect a blocked exhaust gas flow condition in said flue.    
     
     
       67. The induced draft, fuel- fired furnace of claim  66  wherein said blocked flue detecting means includes a temperature sensing means adapted to sense hot exhaust gases exhausted into said drafthood means when a blocked exhaust gas flow condition exists in said flue.    
     
     
       68. The induced draft, fuel- fired furnace of claim  66  wherein said blocked flue detecting means is a pressure sensing means adapted to sense an increase in pressure caused by hot exhaust gases exhausted into said drafthood means when a blocked exhaust gas flow condition exists in said flue.    
     
     
       69. The induced draft, fuel- fired furnace of claim  64  wherein said igniting means includes a standing pilot light.