Gas pilot system and method having improved oxygen level detection capability and gas fueled device including the same

Abstract

A pilot system including a pilot including a nozzle and a sensor adjacent to the nozzle. The sensor determines whether or not the pilot flame is in a predetermined position relative to the nozzle.

I claim:  
     
         1 . A pilot system for generating a pilot flame, comprising: 
 a pilot including a nozzle; and    an electrical resistance measurement device adjacent to the nozzle.    
     
     
         2 . A pilot system as claimed in  claim 1 , wherein the electrical resistance measurement device comprises a pair of spaced electrodes.  
     
     
         3 . A pilot system as claimed in  claim 1 , further comprising: 
 an ignitor positioned adjacent to the nozzle;    wherein the electrical resistance measurement device is located between the nozzle and the ignitor.    
     
     
         4 . A pilot system as claimed in  claim 1 , further comprising: 
 a shield adjacent to the nozzle and defining an open region through which the electrical resistance measurement device extends.    
     
     
         5 . A pilot system as claimed in  claim 1 , further comprising: 
 a mixing chamber located upstream of the nozzle including a gas inlet, an air inlet and a gas/air mixture outlet in communication with the nozzle.    
     
     
         6 . A pilot system as claimed in  claim 1 , wherein the pilot is constructed such that the pilot flame will be located in a first position in response to a first oxygen level and a second position in response to a second oxygen level, the second oxygen level being less than the first oxygen level, and the electrical resistance measurement device will measure a level of electrical resistance indicative of an allowable oxygen level when the pilot flame is in the first position and will not measure a level of electrical resistance indicative of an allowable oxygen level when the pilot flame is in the second position.  
     
     
         7 . A gas fueled device, comprising: 
 a burner;    a pilot including a nozzle associated with the burner; and    an electrical resistance measurement device adjacent to the nozzle.    
     
     
         8 . A gas fueled device as claimed in  claim 7 , wherein the burner comprises a ceramic plaque.  
     
     
         9 . A gas fueled device as claimed in  claim 7 , wherein the electrical resistance measurement device comprises a pair of spaced electrodes.  
     
     
         10 . A gas fueled device as claimed in  claim 7 , further comprising: 
 an ignitor positioned adjacent to the nozzle;    wherein the electrical resistance measurement device is located between the nozzle and the ignitor.    
     
     
         11 . A gas fueled device as claimed in  claim 7 , further comprising: 
 a shield adjacent to the nozzle and defining an open region through which the electrical resistance measurement device extends.    
     
     
         12 . A gas fueled device as claimed in  claim 7 , further comprising: 
 a mixing chamber located upstream of the nozzle including a gas inlet, an air inlet and a gas/air mixture outlet in communication with the nozzle.    
     
     
         13 . A gas fueled device as claimed in  claim 7 , wherein the pilot is constructed such that the pilot flame will be located in a first position in response to a first oxygen level and a second position in response to a second oxygen level, the second oxygen level being less than the first oxygen level, and the electrical resistance measurement device will measure a level of electrical resistance indicative of an allowable oxygen level when the pilot flame is in the first position and will not measure a level of electrical resistance indicative of an allowable oxygen level when the pilot flame is in the second position.  
     
     
         14 . A gas fueled device as claimed in  claim 13 , further comprising: 
 a gas inlet operably connected to the pilot; and    a control device operably connected to the electrical resistance measurement device that prevents gas flow from the gas inlet to the pilot when the electrical resistance measurement device does not measure a level of electrical resistance indicative of an allowable oxygen level.    
     
     
         15 . A gas fueled device as claimed in  claim 13 , further comprising: 
 a gas inlet operably connected to the burner; and    a control device operably connected to the electrical resistance measurement device that prevents gas flow from the gas inlet to the burner when the electrical resistance measurement device does not measure a level of electrical resistance indicative of an allowable oxygen level.    
     
     
         16 . A method of monitoring a pilot flame produced by a pilot, comprising the steps of: 
 determining whether the pilot flame is located in a predetermined region associated with the pilot by sensing a property other than temperature; and    preventing gas from flowing to the pilot in response to a determination that the pilot flame is not in the predetermined region.    
     
     
         17 . A method as claimed in  claim 16 , wherein the step of determining whether the flame is located in the predetermined region comprises measuring electrical resistance in the predetermined region.  
     
     
         18 . A method as claimed in  claim 16 , wherein the gas pilot includes a nozzle and an ignitor defining a region therebetween and the step of determining whether the pilot flame is located in a predetermined region comprises determining whether the pilot flame is located between the nozzle and the ignitor.  
     
     
         19 . A method as claimed in  claim 16 , wherein the step of preventing gas flow from flowing to the pilot comprises closing a valve.  
     
     
         20 . A method as claimed in  claim 16 , wherein the gas pilot includes a nozzle, the method further comprising the step of: 
 mixing gas with ambient air to form an air/gas mixture; and    providing the air/gas mixture to the nozzle.    
     
     
         21 . A pilot system for generating a pilot flame, comprising: 
 a pilot including a nozzle; and    a measurement device adjacent to the nozzle that measures a property other than temperature.    
     
     
         22 . A pilot system as claimed in  claim 21 , wherein the measurement device comprises an electrical resistance measurement device.  
     
     
         23 . A pilot system as claimed in  claim 22 , wherein the electrical resistance measurement device comprises a pair of spaced electrodes.  
     
     
         24 . A pilot system as claimed in  claim 22 , further comprising: 
 an ignitor positioned adjacent to the nozzle;    wherein the electrical resistance measurement device is located between the nozzle and the ignitor.    
     
     
         25 . A pilot system as claimed in  claim 21 , wherein the pilot is constructed such that the pilot flame will be located in a first position in response to a first oxygen level and a second position in response to a second oxygen level, the second oxygen level being less than the first oxygen level, and the measurement device will measure a level of the property other than temperature that is indicative of an allowable oxygen level when the pilot flame is in the first position and will not measure a level of the property other than temperature that is indicative of an allowable oxygen level when the pilot flame is in the second position.  
     
     
         26 . A pilot system as claimed in  claim 21 , wherein the measurement device comprises a sensor that senses electromagnetic radiation.  
     
     
         27 . A pilot system as claimed in  claim 26 , further comprising: 
 an ignitor positioned adjacent to the nozzle that emits electromagnetic radiation when heat by the pilot flame;    wherein the sensor senses electromagnetic radiation from the ignitor.    
     
     
         28 . A gas fueled device, comprising: 
 a burner;    a pilot including a nozzle associated with the burner; and    a measurement device adjacent to the nozzle that measures a property other than temperature.    
     
     
         29 . A gas fueled device as claimed in  claim 28 , wherein the measurement device comprises an electrical resistance measurement device.  
     
     
         30 . A gas fueled device as claimed in  claim 29 , wherein the electrical resistance measurement device comprises a pair of spaced electrodes.  
     
     
         31 . A gas fueled device as claimed in  claim 28 , wherein the burner comprises a ceramic plaque.  
     
     
         32 . A gas fueled device as claimed in  claim 28 , further comprising: 
 an ignitor positioned adjacent to the nozzle;    wherein the electrical resistance measurement device is located between the nozzle and the ignitor.    
     
     
         33 . A gas fueled device as claimed in  claim 28 , wherein the pilot is constructed such that the pilot flame will be located in a first position in response to a first oxygen level and a second position in response to a second oxygen level, the second oxygen level being less than the first oxygen level, and the measurement device will measure a level of the property other than temperature that is indicative of an allowable oxygen level when the pilot flame is in the first position and will not measure a level of the property other than temperature that is indicative of an allowable oxygen level when the pilot flame is in the second position.  
     
     
         34 . A gas fueled device as claimed in  claim 28 , wherein the measurement device comprises a sensor that senses electromagnetic radiation.  
     
     
         35 . A gas fueled device as claimed in  claim 34 , further comprising: 
 an ignitor positioned adjacent to the nozzle that emits electromagnetic radiation when heat by the pilot flame;    wherein the sensor senses electromagnetic radiation from the ignitor.    
     
     
         36 . A gas fueled device as claimed in  claim 31 , further comprising: 
 a gas inlet operably connected to the pilot; and    a control device operably connected to the measurement device that prevents gas flow from the gas inlet to the pilot when the measurement device does not measure a level of the property other than temperature indicative of an allowable oxygen level.    
     
     
         37 . A gas fueled device as claimed in  claim 31 , further comprising: 
 a gas inlet operably connected to the burner; and    a control device operably connected to the measurement device that prevents gas flow from the gas inlet to the burner when the measurement device does not measure a level of the property other than temperature indicative of an allowable oxygen level.