Combustion apparatus

Abstract

An object of the present invention is to provide a combustion apparatus capable of certainly detecting a shortage of an amount of air relative to that of fuel gas. A combustion apparatus 1 is adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air 67, including a first ion current measuring element 65 positioned at a site where a flame of the primary combustion is to take place and a second ion current measuring element 66 adjacent to a secondary air supply opening 20, 21, 63, or 64 for supplying the secondary air 67, so as to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas based on measured values by the first and the second ion current measuring elements 65 and 66.

1 . A combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air, comprising:
 a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place; and   a second ion current measuring element adjacent to a secondary air supply opening for supplying the secondary air,   so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.   
   
   
       2 . The combustion apparatus as defined in  claim 1 ,
 being adapted to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas.   
   
   
       3 . The combustion apparatus as defined in  claim 2 , further comprising a memory storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide,
 being adapted to compare a calculated value of the difference with the standard value stored in the memory, and   being adapted to perform one selected from a group consisting of (a) increasing a ratio of amount of the secondary air to that of the primary air, (b) increasing a total amount of the primary and the secondary air, and (c) reducing fuel gas supply, in the case that the calculated value is bigger than the value stored in the memory.   
   
   
       4 . The combustion apparatus as defined in  claim 1 , comprising:
 at least one premixer adapted to introduce thereinto the fuel gas along with the primary air to generate the air-fuel mixture in an oxygen-deficient condition;   at least one air passage member of a wall shape having the secondary air supply opening for supplying the secondary air at its distal end;   at least one burner port assembly arranged between two of the air passage members or between the air passage member and another wall; and   at least one combustion part formed by a space enclosed by the burner port assembly and the air passage member,   wherein the air-fuel mixture is discharged from the burner port assembly into the combustion part to perform the primary combustion and further perform the secondary combustion upon supply of the secondary air from the secondary air supply opening of the air passage member.   
   
   
       5 . The combustion apparatus as defined in  claim 4 ,
 defining three routes through which air flows: a first route within the air passage member, a second route from between the premixer and the burner port assembly to the combustion part, and a third route through which air flows with the fuel gas, the first and the second routes being adapted to supply the secondary air, the third route being adapted to introduce the primary air,   further comprising a memory for storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide,   being adapted to compare a calculated value of the difference with the standard value stored in the memory, and   being adapted to increase supply of the secondary air flowing through the first and the second routes in the case that the calculated value is bigger than the standard value stored in the memory.   
   
   
       6 . The combustion apparatus as defined in  claim 1 ,
 being adapted to blow air to the second ion current measuring element.   
   
   
       7 . The combustion apparatus as defined in  claim 1 ,
 wherein the first and the second ion current measuring elements have 15 each a distal end, the distal end of the first ion current measuring element being curved or bent toward the upstream of fuel gas flow, and the distal end of the second ion current measuring element being curbed or bent toward the center of a combustion zone.   
   
   
       8 . The combustion apparatus as defined in  claim 1 , further comprising a memory storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide. 
   
   
       9 . The combustion apparatus as defined in  claim 8 ,
 the standard value having a predetermined width.   
   
   
       10 . The combustion apparatus as defined in  claim 8 ,
 being adapted to compare a calculated value of the difference with the standard value stored in the memory.   
   
   
       11 . The combustion apparatus as defined in  claim 10 ,
 being adapted to increase air supply and/or reduce fuel gas supply in the case that the calculated value is bigger than the standard value stored in the memory.   
   
   
       12 . A combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further perform a secondary combustion upon supply of secondary air, comprising:
 a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place;   an air supply port for supplying air different from the primary air to a base of the flame of the primary combustion; and   a second ion current measuring element adjacent to the air supply port,   so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.   
   
   
       13 . The combustion apparatus as defined in  claim 12 ,
 being adapted to control at least one selected from a group consisting of (a) a ratio of an amount of the primary air to that of the secondary air, (b) a total amount of the primary and the secondary air, and (c) an amount of the fuel gas.   
   
   
       14 . The combustion apparatus as defined in  claim 12 ,
 being adapted to blow air to the second ion current measuring element.   
   
   
       15 . The combustion apparatus as defined in  claim 12 , further comprising:
 at least one premixer adapted to introduce thereinto the fuel gas along with the primary air to generate the air-fuel mixture in an oxygen-deficient condition;   at least one air passage member of a wall shape having a secondary air supply opening for supplying the secondary air;   at least one burner port assembly arranged between two of the air passage members or between the air passage member and another wall; and   at least one combustion part formed by a space enclosed by the burner port assembly and the air passage member,   wherein the air-fuel mixture is discharged from the burner port assembly into the combustion part to perform the primary combustion.   
   
   
       16 . The combustion apparatus as defined in  claim 15 ,
 being adapted to blow air to the second ion current measuring element.   
   
   
       17 . The combustion apparatus as defined in  claim 14 ,
 defining three routes through which air flows: a first route within the air passage member, a second route from between the premixer and the burner port assembly to the combustion part, and a third route through which air flows with the fuel gas, the first and the second routes being adapted to supply the secondary air, the third route being adapted to introduce the primary air,   further comprising a memory for storing a standard value relating to difference between output values measured by the first and the second ion current measuring elements corresponding to a regulation value of emission concentration of carbon monoxide,   being adapted to compare a calculated value of the difference with the standard value stored in the memory, and   being adapted to increase supply of the secondary air flowing through the first and the second routes in the case that the calculated value is bigger than the standard value stored in the memory.   
   
   
       18 . The combustion apparatus as defined in  claim 17 ,
 being adapted to blow air to the second ion current measuring element.   
   
   
       19 . A combustion apparatus adapted to perform a primary combustion of air-fuel mixture in an oxygen-deficient condition composed of mixture of primary air and fuel gas and further to facilitate combustion upon supply of air different from the primary air, comprising:
 a first ion current measuring element positioned at a site where a flame of the primary combustion is to take place;   an air supply port for supplying the air different from the primary air; and   a second ion current measuring element adjacent to the air supply port,   so as to control at least one of supplied air and fuel gas based on measured values by the first and the second ion current measuring elements.   
   
   
       20 . The combustion apparatus as defined in  claim 19 ,
 being adapted to blow air to the second ion current measuring element.