Premixing device and combustion device including the same

Abstract

A premixing device A includes: a premixing flow path 3 including first and second flow paths 3a, 3b; first and second fuel gas outlets 80a, 80b; and a flapper 5 swingably located on the first flow path 3a. The premixing device A is configured that, when the flapper 5 is changed from a closed state to an open state, auxiliary flow paths 38a, 38b on a proximal end side and a distal end side are formed between respective regions on the proximal and distal end sides of the flapper 5 and a predetermined seat part 47, and, through the auxiliary flow paths 38a, 38b, an air flow from a predetermined specific flow path region 3a toward a region downstream of the flapper 5 in the air flow direction and a fuel gas outflow from the first fuel gas outlet 80a together with the air flow are generated.

What is claimed is: 
     
         1 . A premixing device, comprising:
 a premixing flow path, supplied with air from outside and provided for mixing a fuel gas with the air to generate a gas mixture;   a partition wall part, partitioning the premixing flow path into a first flow path and a second flow path in parallel arrangement; and   a first fuel gas outlet and a second fuel gas outlet, through which the fuel gas is able to flow out to the first flow path and the second flow path by using a negative pressure generated due to air flows in the first flow path and the second flow path,   wherein x and y directions intersecting each other are provided as directions intersecting an air flow direction in the first and second flow paths, and the premixing device comprises:   a blade part, provided on the first flow path, wherein the first fuel gas outlet is provided toward a downstream side of the air flow direction;   a specific flow path region, as a portion of the first flow path and disposed in adjacency with a single side or both sides of the blade part in the x direction;   a flapper, provided, in the first flow path, at a position downstream of the blade part and the specific flow path region; and   a seat part, provided for the flapper, and comprising a periphery part of the first fuel gas outlet and an opening periphery part on a downstream side of the specific flow path region in the air flow direction,   wherein a proximal end of the flapper is supported by a support art to swing with the support part as a center, and, the flapper is settable to a closed state opposite to and in contact with the seat part in a configuration where the proximal end and a distal end are arranged in the y direction, so as to be able to open and close the first fuel gas outlet and the specific flow path region in accordance with an air flow rate of the premixing flow path, and   the premixing device is configured that, when the flapper is changed from the closed state to an open state, auxiliary flow paths on a proximal end side and a distal end side are formed between respective regions on the proximal end side and the distal end side of the flapper and the seat part, and through the auxiliary flow paths, an air flow from the specific flow path region toward a region downstream of the flapper in the air flow direction and a fuel gas outflow from the first fuel gas outlet, which accompanies the air flow, are generated.   
     
     
         2 . The premixing device as claimed in  claim 1 ,
 when the flapper is in the closed state, the first fuel gas outlet is arranged in a fully closed state by using the flapper, while the specific flow path region is arranged in a non-fully closed state in which a portion located close to the proximal end of the flapper is in the open state, and it is configured that, the air flow from the specific flow path region toward the region downstream of the flapper in the air flow direction is able to be generated through a portion of the open state.   
     
     
         3 . The premixing device as claimed in  claim 1 ,
 wherein the flapper comprises a flapper body part and a connection part, the flapper body part has a plate shape and is opposite to and in contact with the seat part when the flapper is in the closed state, and the connection part is connected with the flapper body part and at least a portion of the connection part is comprised in the proximal end, and   the support part is a portion that supports the connection part to be able to swing around a center line extending in the x direction, and is located on a downstream side with respect to the flapper body part in the air flow direction and on a side of the partition wall part when the flapper is in the closed state.   
     
     
         4 . The premixing device as claimed in  claim 3 , wherein the connection part is configured to be spaced apart from the seat part when the flapper is in the closed state, so that a first gap is formed between the connection part and the seat part, and
 the connection part is configured so that, when the flapper is changed from the closed state to the open state, the first gap forms the auxiliary flow path on the proximal end side.   
     
     
         5 . The premixing device as claimed in  claim 4 , wherein the connection part of the flapper has an inclined surface part inclined so that, in a region facing the seat part when the flapper is in the closed state, the closer from a side of the flapper body part toward a side of the support part, the greater a separation distance with respect to the seat part. 
     
     
         6 . The premixing device as claimed in  claim 4 , wherein, a second gap is formed between the connection part and the partition wall part for communication of the first gap with the region downstream of the flapper in the air flow direction when the flapper is in the closed state and when the flapper is changed from the closed state to the open state. 
     
     
         7 . The premixing device as claimed in  claim 4 , wherein a hole part or a notch part is provided on the proximal end part of the flapper for communication of the first gap with the region of the first flow path downstream of the flapper in the air flow direction when the flapper is in the closed state and when the flapper is changed from the closed state to the open state. 
     
     
         8 . A combustion device, comprising:
 a premixing device, generating a gas mixture mixing air and a fuel gas; and   a burner part, receiving supply of the gas mixture from the premixing device to cause combustion of the fuel gas.   wherein the premixing device as claimed in  claim 1  is used as the premixing device.