Premixing device and combustion device including the same

Abstract

A premixing device which includes a premixing flow path including a first flow path and a second flow path, and a first fuel gas outlet and a second fuel gas outlet includes: a first blade section which is provided in the first flow path, and with which the first fuel gas outlet is provided; a protruding wall section which is provided on the first blade section; and a flapper which oscillates at a position downstream in the air flow direction than the first blade portion of the first flow path. When the flapper is in an open state below a specified opening degree, the flow of air from the first flow path to the first fuel gas outlet is capable of being suppressed by the protruding wall section.

What is claimed is: 
     
         1 . A premixing device which comprises
 a premixing flow path to which air is supplied from the outside and for generating a mixture by mixing fuel gas with the air,   a partition wall section which divides the premixing flow path into a first flow path and a second flow path arranged in parallel, and   a first fuel gas outlet and a second fuel gas outlet that are capable of discharging fuel gas into the first flow path and the second flow path by utilizing negative pressure generated by air flow in the first flow path and the second flow path,   the premixing device comprising:   a first blade section, provided in the first flow path, and provided with the first fuel gas outlet facing a downstream side in an air flow direction;   a protruding wall section, provided on the first blade section so as to protrude from an edge section of the first fuel gas outlet towards a downstream side in the air flow direction; and   a flapper, oscillating in a direction facing the first blade section, at a position downstream in the air flow direction than the first blade section within the first flow path, and being capable of opening and closing both the first flow path and the first fuel gas outlet according to an air flow rate of the premixing flow path while avoiding interference with the protruding wall section, and   when the flapper is in an open state below a specified opening degree, a configuration being such that flow of air from the first flow path into the first fuel gas outlet is capable of being suppressed by the protruding wall section.   
     
     
         2 . The premixing device according to  claim 1 , wherein
 as a way to avoid interference between the flapper and the protruding wall section, the flapper comprises a hole section into which the protruding wall section enters when the flapper is in an open state below the specified opening degree.   
     
     
         3 . The premixing device according to  claim 2 , wherein
 the protruding wall section has a height such that the height allows the protruding wall to exit from the hole section of the flapper when the flapper is in an open state greater than the specified opening degree.   
     
     
         4 . The premixing device according to  claim 3 , wherein
 the hole section of the flapper is an elongated hole extending in a specific direction from a base end section side closer to an oscillation center of the flapper to a tip section,   the protruding wall section is rib-shaped extending in a direction corresponding to the specific direction, and a chamfered section that is a flat-surface shape or a curved-surface shape is provided on a corner section of a tip section of the protruding wall section that is farther from the oscillation center of the flapper.   
     
     
         5 . The premixing device according to  claim 1 , wherein
 the protruding wall section extends continuously along the first fuel gas outlet, and a length thereof is substantially the same as a length of the first fuel gas outlet.   
     
     
         6 . The premixing device according to  claim 1 , wherein
 an x direction and a y direction that intersect with each other exist as directions which intersect with the air flow direction,   the first blade section extends in the y direction so as to span between a part and another part of an inner wall of the first flow path, thereby dividing a part of the first flow path into a pair of divided flow paths, and in the x direction, the first blade section and the first fuel gas outlet are positioned between the pair of divided flow paths, and   a pair of protruding wall sections is positioned at both edge sections in the x direction of the first fuel gas outlet as the protruding wall section.   
     
     
         7 . The premixing device according to  claim 6 , wherein
 the protruding wall sections are not provided on the both edge sections in the y direction of the first fuel gas outlet of the first blade section, and when the flapper is in an open state below the specified opening degree, a configuration is such that air in the first flow path is allowed to flow towards the both edge sections in the y direction of the first fuel gas outlet.   
     
     
         8 . The premixing device according to  claim 1 , further comprising:
 a premixing flow path forming member, forming the premixing flow path;   a second blade section, provided inside the second flow path with one end section connected to a peripheral wall section of the premixing flow path forming member and the other end section connected to the first blade section via the partition wall section, and provided with the second fuel gas outlet facing a downstream side in the air flow direction;   a fuel gas receiving section, provided on the peripheral wall section of the premixing flow path forming member and receiving a supply of fuel gas from the outside;   a second fuel gas flow path, provided inside the second blade section to be capable of leading a part of the fuel gas supplied to the fuel gas receiving section to the second fuel gas outlet; and   a first fuel gas flow path, provided to extend from inside the second blade section to inside the first blade section, and capable of leading another part of the fuel gas supplied to the fuel gas receiving section to the first fuel gas outlet.   
     
     
         9 . A combustion device, comprising:
 a fan;   a premixing device, provided on an intake side of the fan, generating a mixture by mixing air and fuel gas, and sending the mixture to the fan; and   a burner section, receiving a supply of the mixture from the fan and combusting the fuel gas, and   the premixing device according to  claim 1  being used as the premixing device.