Patent Application
20230023104
The present invention relates to a totally aerated combustion burner which is provided with a combustion plate part through which an air-fuel mixture is ejected.
In this kind of totally aerated combustion burner, there is conventionally known an arrangement in which the combustion plate part comprises: a permeable body through which the air-fuel mixture can pass (hereinafter referred to as “air-fuel mixture permeable body”) made from metallic fibers; and a distribution plate having formed therein a multiplicity of distribution holes and being stacked on a back surface of the air-fuel mixture permeable body (see, e.g., patent document 1).
The air-fuel mixture permeable body is constructed by one metallic-fiber woven body made by weaving metallic-fiber threads that are obtained by bundling a plurality of metallic fibers. In order to improve the combustibility (particularly, resistance against lifting), it is necessary to disperse the air-fuel mixture moderately through the metallic-fiber woven body. Specifically, it is necessary to reduce the amount of ejection of the air-fuel mixture out of the meshes and also to make sure that an appropriate amount of air-fuel mixture permeates through the metallic-fiber threads so that, as a consequence, the flame to be formed by the combustion of the air-fuel mixture that has ejected from the meshes can be stabilized by a small flame that is hard to lifted and is formed by the combustion of the air-fuel mixture permeated through the metallic-fiber threads. For that purpose, it is required to make the meshes smaller and also to increase the number of metallic fibers per one metallic-fiber thread. Then, in order to increase the number of metallic fibers per one metallic-fiber thread and further to make smaller the meshes, flexibility will be required of the metallic fibers. As a solution, conventionally there used to have woven metallic-fiber woven bodies by using metallic-fiber threads of dozens of ultrafine metallic fibers of less than 0.04 mm in diameter, which are superior in flexibility. This kind of ultrafine metallic fibers are, however, higher in cost. Therefore, the air-fuel mixture permeable body constructed by the metallic-fiber woven body which is wound by metallic-fiber threads made up of ultrafine metallic fibers become fairly expensive.
By the way, larger-diameter metallic fibers above 0.07 mm in diameter are less expensive. Therefore, it is considered to weave a metallic-fiber woven body by metallic-fiber threads that are obtained by bundling such metallic fibers. However, in order to weave the metallic-fiber woven body by this kind of metallic-fiber threads, it is necessary to reduce the number of metallic fibers per one metallic-fiber thread, or to enlarge the meshes. This will make insufficient the dispersion of the air-fuel mixture in the air-fuel mixture woven body, resulting in poor combustibility.
In view of the above points, this invention has a problem of providing a totally aerated combustion burner in which the combustion performance will not be deteriorated even without employing ultrafine metallic fibers, and in which the cost reduction of the air-fuel mixture permeable body can be attained.
In order to solve the above problem, this invention is a totally aerated combustion burner comprising: a combustion plate part through which an air-fuel mixture is ejected, the combustion plate part including: an air-fuel mixture permeable body made from metallic fibers to allow the air-fuel mixture to pass therethrough; and a distribution plate having formed therein a multiplicity of distribution holes, and being stacked on a back surface of the air-fuel mixture permeable body, the back surface being defined as an upstream-side surface as seen along a flow of the air-fuel mixture through the air-fuel mixture permeable body, whereby the air-fuel mixture can be ejected through the distribution holes and the air-fuel mixture permeable body. In the totally aerated combustion burner: the air-fuel mixture permeable body is constructed by laminating a plurality of metallic-fiber woven bodies, each of the metallic-fiber woven bodies being made by weaving metallic-fiber threads obtained by bundling a plurality of metallic fibers; and the plurality of metallic-fiber woven bodies are laminated such that part of (partial) meshes in one metallic-fiber woven body that lies adjacent to another metallic-fiber woven body in a laminating direction, overlaps a portion other than meshes in said another metallic-fiber woven body.
According to this invention, even if the number of metallic fibers per one metallic-fiber thread decreases or the meshes become larger as a result of employing larger-diameter metallic fibers, the air-fuel mixture permeable body is constructed by laminating the plurality of metallic-fiber woven bodies such that a part of meshes in one metallic-fiber woven body that lies adjacent to another metallic-fiber woven body in the laminating direction, overlaps a portion other than meshes in said another metallic-fiber woven body. Therefore, dispersion of the air-fuel mixture through the air-fuel mixture permeable body is accelerated. There will thus be no possibility of deterioration in the combustibility. In addition, since larger-diameter metallic fibers are considerably less expensive, even if a plurality of metallic-fiber woven bodies are laminated, they are smaller in cost than one metallic-fiber woven body obtained by weaving metallic-fiber threads in which, like in the conventional example, ultrafine metallic fibers are bundled. In this manner, the cost of the air-fuel mixture permeable body can be reduced.
Further, according to this invention, preferably a number of metallic fibers per one metallic-fiber thread for said one metallic-fiber woven body is smaller than the number of metallic fibers per one metallic-fiber thread for said another metallic-fiber woven body, and the meshes in said one metallic-fiber woven body are smaller in size than the meshes in said another metallic-fiber woven body. According to this arrangement, in whichever positional relationship said one metallic-fiber woven body may be laminated relative to said another metallic-fiber woven body, the part other than the meshes in said one metallic-fiber woven body will overlap a part of the meshes in said another metallic-fiber woven body. Therefore, at the time of laminating a plurality of metallic-fiber woven bodies, there will be no need of controlling the position of each of the metallic-fiber woven bodies, thereby improving the ease in assembling. By the way, the number of metallic fibers per one metallic-fiber thread for said another metallic-fiber woven body in which mesh sizes are enlarged, is relatively large in quantity, an adequate amount of air-fuel mixture will be permeated through this metallic-fiber threads. In consequence, a flame that is hard to be lifted is stably formed, thereby securing the resistance to the lifting characteristics.
Further, in case the plurality of metallic-fiber woven bodies are constructed by the same kind of metallic-fiber woven bodies of the same size in the meshes obtained by weaving the same kind of metallic-fiber threads which are the same in number of metallic fibers per one metallic thread, if a course direction of said one metallic-fiber woven body crosses the course direction of said another metallic-fiber woven body, the plurality of metallic-fiber woven bodies are laminated such that a part of meshes in said one metallic-fiber woven body overlaps a portion other than meshes in said another metallic-fiber woven body. According to this arrangement, when a plurality of metallic-fiber woven bodies are laminated, the course direction of each of the metallic-fiber woven bodies must be controlled. But this control is easier than the control of the positions of each of the metallic-fiber woven bodies. Therefore, the ease in assembling will not be deteriorated so much.
Still furthermore, the plurality of metallic-fiber woven bodies may be constructed by weaving the same kind of metallic-fiber threads that are equal in number of metallic fibers per one metallic-fiber thread. The shape of the meshes in said one metallic-fiber woven body and the shape of the meshes in said another metallic-fiber woven body may be made different from each other by varying the way of weaving the meshes. It may thus be so arranged that a part of meshes in said one metallic-fiber woven body overlaps a portion other than meshes in said another metallic-fiber woven body. This arrangement can similarly improve the ease of assembling.
A combustion apparatus shown in
The heat exchanger 3 is made up of a fin-tube type of heat exchanger provided with a multiplicity of fins 31 and a plurality of heat-absorbing tubes 32 which penetrate these fins 31. On an outside surface of side plates 23, 24 on laterally one side and the opposite side of the combustion box 2, there are mounted a plurality of connection covers 33 which define connection passages of the two heat absorbing tubes 32, 32 that lie next between each of the side plates 23, 24. In this manner, all the heat-absorbing tubes 32 are connected together in series with one another. Further, the connection covers 33 which define connection passages between the side plates 24 of the laterally opposite side are provided with a water inlet 34, the connection passages being connected to the heat absorbing tubes 32 on an upstream end of the heat exchanger 3.
Furthermore, on an inside of the rear-side side plate 25 of the combustion box 2, the inside being above the heat exchanger 3, there are disposed vertically arranged three pieces of first water passages 51 made up of tubes, in a manner to contact the rear-side side plate 25. Also on an inside of the front-side side plate 26 of the combustion box 2, the inside being above the heat exchanger 3, there are disposed vertically arranged three pieces of third water passages 53 made up of tubes, in a manner to contact the front-side side plate 26. In addition, on an outside surface of the laterally one-side side plate 23 of the combustion box 2, there are mounted: an inlet-side header cover 51 which defines a connection passage which connects the vertically disposed three pieces of first water passages 51 to the heat absorbing tube 32 on a downstream end of the heat exchanger 3, between the laterally one-side side plate 23; and an outlet-side header cover 52 which defines a connection passage for the vertically disposed three water passages 53 between the laterally one-side side plate 23; and a hot water outlet 53 is disposed on the outlet-side header cover 52. Furthermore, as shown in
Further, the front-side side plate 26 of the combustion box 2 has mounted thereon electrode parts 6 which are protruded through the side plate portion between the two, i.e., the first and the second from the top, of the third water passages 53, 53, so as to protrude into the combustion box 2, the electrode parts 6 inclusive of an ignition electrode 61, a grounding electrode 62, and a flame rod 63. The electrode parts 6 are additionally provided with an inspection window 64 through which the inside of the combustion box 2 can be visually inspected.
Next, detailed description will be made of the totally aerated combustion burner 1. The burner body 11 is provided with an inlet port 113 for connecting thereto a fan 4 which supplies an air-fuel mixture. The inlet port 113 has mounted thereon a check valve 13 for preventing the air-fuel mixture, that remains inside the burner body 11 at the time of stopping of the fan 4, from flowing backward to the side of the fan 4. The check valve 13 is made up of: a resin-made valve box 131 which is built into the inlet port 113; and a resin-made valve plate 132 rotatably mounted, so as to be freely opened or closed, in an opening portion of the valve box 131, the opening portion facing the inside of the burner body 11.
With reference also to
The burner frame 121 has: an opening peripheral part 121a that is positioned on the same plane as the opening 122; a side-plate part 121b which is bent from the opening peripheral part 121a to the burner-body 11 side (i.e., upward); and a frame flange part 121c which protrudes outward from an upper end of the side-plate part 121b. The combustion plate part 12 is assembled, in a state in which the distribution plate 124 is placed on (i.e., is overlapped with) the rear surface of the air-fuel mixture permeable body 123, peripheral portion of the permeable body 123 and the distribution plate 124 is spot-welded, at a certain spacing, to the opening peripheral part 121a of the burner frame 121. The frame flange part 121c is sandwiched into a space between the body flange part 112 and the box flange part 22. Further, by interposing a packing 7 between the frame flange part 121c and the body flange part 112, sealing properties are secured. Still furthermore, a thermal insulation material 8 is mounted on a lower surface of the frame flange part 121c.
The air-fuel mixture permeable body 123 is constructed by laminating a plurality of (e.g., three) metallic-fiber woven bodies 1231, 1232, 1233. These three metallic-fiber woven bodies 1231, 1232, 1233 get spot welded together at a plurality of spots so that they do not get peeled off from each other. With reference also to
As shown in
According to this arrangement, by employing large-diameter metallic fibers 123a, even if the number of metallic fibers 123a per one metallic-fiber thread 123b becomes fewer or even if the meshes 123c become larger, the portion other than the meshes 123c in the second metallic-fiber woven body 1232 will overlap the meshes 123c in each of the first and the third metallic-fiber woven bodies 1231, 1233. Therefore, the dispersion of the air-fuel mixture will be accelerated in the air-fuel mixture permeable body 123. There will thus be no deterioration in the combustibility. Further, since the larger-diameter metallic fibers 123a are considerably less expensive, even if three sheets of the first through the third metallic-fiber woven bodies 1231, 1232, 1233 are laminated, they are less expensive than one metallic-fiber woven body that is woven by metallic-fiber threads obtained by bundling ultrafine metallic fibers less than 0.04 mm in diameter as in the conventional example. Cost of the air-fuel mixture permeable body 123 can thus be reduced.
By the way, in case the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233 are constructed by the same kind of metallic-fiber woven bodies of the same size in the meshes 123c. The metallic-fiber woven bodies are made by weaving the same kind of metallic-fiber thread 123b that are same in number of metallic fibers 123a per one metallic-fiber thread 123b, the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233 are laminated so that the meshes 123c of the second metallic-fiber woven bodies 1232 do not overlap a part of the meshes in each of the first and the third metallic-fiber woven bodies 1231, 1233. In this arrangement, the portion other than the meshes 123c in the second metallic-fiber woven bodies 1232 overlap parts of the meshes 123c in the first and the third metallic-fiber woven bodies 1231, 1233. However, in this arrangement, at the time of laminating the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233, it becomes necessary to control the positions of each of the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233, resulting in poor assembling efficiency.
As a solution, in this embodiment, the meshes 123c in the second metallic-fiber woven body 1232 as shown in
In order to minimize the meshes 123c, it is necessary to reduce the rigidity of the metallic-fiber threads 123b. Therefore, the number of metallic fibers 123a per one metallic-fiber thread 123b for the second metallic-fiber woven body 1232, whose meshes are made smaller, is arranged to be smaller (e.g., 4) than the number (e.g., 8) of metallic fibers 123a per one metallic-fiber thread 123b for the first and the third metallic-fiber woven bodies 1231, 1233 whose meshes are made larger. The number of metallic fibers 123a per one metallic fiber thread 123d for the first and the third metallic-fiber woven bodies 1231, 1233 is relatively large in number (quantity). Therefore, an adequate amount of air fuel mixture permeates through these metallic-fiber threads 123b so that a flame harder to be lifted can be stably formed, thereby securing the resistance to the lifting properties.
Descriptions have so far been made of the embodiments of this invention with reference to the drawings. This invention shall, however, not be limited to the above. For example, the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233 may be constructed by the same kind of metallic-fiber woven bodies of the same size in the meshes 123c obtained by weaving the same kind of metallic-fiber thread 123b that are the same in number of metallic fibers per one metallic-fiber thread 123b. A course direction (or wale direction) of the second metallic-fiber woven body 1232 may be arranged to cross the course direction of each of the first and the third metallic-fiber woven bodies 1231, 1233. In this arrangement, too, the portion other than the meshes 123c in the second metallic-fiber woven bodies 1232 overlaps a portion of the meshes 123c in each of the first and the third metallic-fiber woven bodies 1231, 1233. In this case, at the time of laminating the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233, the course direction of each of the metallic-fiber woven bodies 1231, 1232, 1233 must be controlled. This control, however, is relatively easier as compared with the control of position of each of the metallic-fiber woven bodies 1231, 1232, 1233. The ease in assembling will not be deteriorated so much.
Still furthermore, the first, the second, and the third metallic-fiber woven bodies 1231, 1232, 1233 are supposed to have been constructed by metallic-fiber woven bodies by weaving the same kind of metallic-fiber threads 123b that are same in number of metallic fibers 123a per one metallic-fiber thread 123b. The shape of meshes 123c in each of the first and the third metallic-fiber woven bodies 1231, 1233 may be made different from the shape of meshes 123c in the second metallic-fiber woven body 1232, by varying the way of weaving the meshes, such that a portion of the meshes in each of the first and the third metallic-fiber woven bodies 1231, 1233 overlaps a portion other than the meshes 123c of the second metallic-fiber woven body 1232. Still furthermore, in the above-mentioned embodiments, the number of the metallic-fiber woven body which constitutes the air-fuel mixture permeable body 123 is defined to be three pieces (or sheets), but this number may be two or above four.
Furthermore, in the totally aerated combustion burner 1 according to the above-mentioned embodiments, the open surface 111 of the burner body 11 is disposed so as to look downward. But this invention can similarly be applicable to a totally aerated combustion burner whose open surface 111 looks upward. Further, in the above-mentioned embodiments, the air-fuel mixture permeable body 123 is disposed so as to cover the opening 122 of the burner frame 121. This invention is also applicable to a totally aerated combustion burner in which the air-fuel mixture permeable body and the distribution plate are arranged to be cylindrical in shape so that the air-fuel mixture supplied to the cylindrical inner space is ejected outward through the distribution holes and the air-fuel mixture permeable body.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-119495 | Jul 2021 | JP | national |
