JP2020122611A - Burner unit, and hot water device - Google Patents

Abstract

To provide a burner unit that enables the reduction of its production cost and can suitably prevent a trouble of damaging a flame hole plate due to generation of large thermal stress therein.SOLUTION: A burner unit A comprises: a flame hole plate 2 provided with a plurality of flame holes 20; and a frame shaped base 1 comprising a frame shaped front wall 10 abutting on the vicinity of the outer periphery of a surface part of the flame hole plate 2 and an erected wall 11 erected from the front wall 10 on the backside thereof to surround the outer periphery of the flame hole plate 2, wherein the flame hole plate 2 is made from metal, with a gap 4 formed between the outer periphery of the flame hole plate 2 and the erected wall 11 to reduce stress in the flame hole plate 2 resulting from its thermal expansion.SELECTED DRAWING: Figure 2

Description

The present invention relates to a burner unit used as a component of a combustion device that burns fuel gas, and a hot water device including the burner unit.

As a specific example of the burner unit, there is one in which a flame hole plate provided with a plurality of flame holes is fixed to a frame-shaped base. The plurality of flame holes allow a mixed gas of fuel gas and air supplied from the back surface side of the flame hole plate to pass to the front surface side of the flame hole plate, and the combustion area of the fuel gas is provided in the front surface area. It is a hole for forming. The frame-shaped base includes a frame-shaped front wall portion that abuts in the vicinity of the outer peripheral portion of the surface portion of the flame hole plate, and an upright wall portion that stands upright from the front wall portion to the back side thereof and surrounds the outer peripheral portion of the flame hole plate. Have
Here, since the flame hole plate is exposed to the flame, excellent heat resistance is required. Therefore, conventionally, there is a situation in which a ceramic plate is used as a raw material for the flame hole plate.

However, if the ceramic plate is used as the raw material of the flame hole plate, the cost of parts is increased.
As a means for solving this, it is conceivable to make the flame hole plate made of metal such as stainless steel having excellent heat resistance. However, when such a means is adopted, the thermal expansion coefficient of the flame hole plate becomes large. Therefore, a large thermal stress is generated when the flame hole plate is thermally expanded. If this thermal stress increases, there is a concern that the flame hole plate may be damaged, such as cracked.

Japanese Patent No. 6378784 JP, 2018-151121, A

The present invention was devised under the circumstances as described above, and it is possible to reduce the manufacturing cost, and moreover, to appropriately deal with the problem that a large thermal stress is generated and damaged in the flame hole plate. It is an object of the present invention to provide a burner unit that can be eliminated and a hot water device including the burner unit.

In order to solve the above problems, the present invention takes the following technical means.

A burner unit provided by the first aspect of the present invention includes a flame hole plate provided with a plurality of flame holes, a frame-shaped front wall portion that abuts in the vicinity of an outer peripheral portion of a surface portion of the flame hole plate, and A burner unit comprising a frame-shaped base standing upright from the front wall to the back side thereof and having a standing wall surrounding the outer periphery of the flame hole plate, wherein the flame hole plate is made of metal. It is characterized in that a gap for reducing stress at the time of thermal expansion of the flame hole plate is formed between the outer peripheral portion of the flame hole plate and the rising wall portion.

With such a configuration, the following effects can be obtained.
That is, since the flame hole plate is made of metal, it is possible to reduce the component cost and the overall manufacturing cost as compared with the conventional technique using the ceramic plate. On the other hand, between the outer periphery of the flame hole plate and the standing wall of the frame-shaped base, there is a gap for stress reduction during thermal expansion of the flame hole plate. At this time, the flame hole plate is prevented from being strongly pressed against the standing wall portion of the frame-shaped base, and a large thermal stress is prevented from being generated in the flame hole plate. Therefore, the flame hole plate can be prevented from being damaged due to thermal stress.

In the present invention, preferably, further provided is a distribution plate having air permeability arranged on the back side of the flame hole plate so as to face the flame hole plate and fixed to the frame-shaped base. The distribution plate is provided with a plurality of convex portions that protrude toward the flame hole plate side and come into contact with the flame hole plate, and the flame hole plate is connected to the frame-shaped base and the distribution plate. In a state in which it is not held, it is sandwiched and held between the plurality of convex portions and the front wall portion.

With such a configuration, the following effects can be obtained.
First, the flame hole plate is sandwiched and held between the frame-shaped base and the plurality of convex portions of the distribution plate without being joined to the frame-shaped base and the distribution plate. At the time of thermal expansion of the flame hole plate, it is possible to smoothly deform the flame hole plate in the direction intersecting the sandwiching direction (the vertical width direction and the horizontal width direction of the flame hole plate). This makes it more difficult to generate thermal stress in the flame hole plate.
Secondly, when manufacturing the burner unit, the step of fixing the flame hole plate to the frame-shaped base by welding or the like is not required, which is more preferable in reducing the manufacturing cost.
Thirdly, the plurality of convex portions of the distribution plate also serve as spacers that form a space between the distribution plate and the flame hole plate. Therefore, it is not necessary to separately provide a dedicated member for forming a space between the distribution plate and the flame hole plate, and it is possible to further reduce the manufacturing cost.

In the present invention, preferably, the flame hole plate is provided with at least one positioning hole or a positioning recess, and the distribution plate enters the positioning hole or the positioning recess. One positioning protrusion or a plurality of positioning protrusions arranged close to each other is provided.

According to such a configuration, the flame hole plate can be positioned, and the position of the flame hole plate becomes unstable due to the formation of the stress reducing gap around the outer circumference of the flame hole plate. Can be appropriately prevented. When a plurality of positioning protrusions are provided, it is possible to prevent the flame hole plate from rotating. On the other hand, according to the configuration in which only one positioning projection is provided or the plurality of positioning projections are provided close to each other, when the flame hole plate thermally expands, contact with the positioning projection is caused. Thermal stress may not occur or may be small.

In the present invention, preferably, a flange portion is continuously provided on the upright wall portion of the frame-shaped base, and an extension portion overlapping the flange portion is provided on the distribution plate, and these extension portions are provided. The installation portion and the flange portion are attached to the burner unit attachment target portion via a common fastening member or welded portion.

With such a configuration, the distribution plate mounting portion for the frame-shaped base and the frame-shaped base mounting portion for the burner unit mounting target portion are integrated, and the structure is rationalized and simplified. Therefore, it is more preferable in reducing the manufacturing cost.

The hot water apparatus provided by the second aspect of the present invention performs hot water heating by the burner unit provided by the first aspect of the present invention and heat recovery from the combustion gas generated using this burner unit. And a heat exchanger capable of performing heat exchange.

With such a configuration, the same effects as those described for the burner unit provided by the first aspect of the present invention can be obtained.

Other features and advantages of the present invention will become more apparent from the following description of the embodiments of the invention with reference to the accompanying drawings.

(A) is a schematic perspective view showing an example of the burner unit according to the present invention, and (b) is an exploded schematic perspective view of the burner unit shown in (a). (A) is a IIa-IIa sectional view of FIG. 1(a), and (b) is a partially enlarged sectional view of (a). It is sectional drawing which shows the other example of this invention. It is sectional drawing which shows the other example of this invention. It is a principal part expanded sectional view which shows the other example of this invention. It is a schematic sectional drawing which shows an example of the hot water apparatus using the burner unit shown in FIG.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

The burner unit A shown in FIGS. 1 and 2 includes a frame-shaped base 1, a flame hole plate 2, and a distribution plate 3.
In this embodiment, the left side of FIG. 1B is the front of the burner unit A. Therefore, the upper portion of FIGS. 1A and 2A and 2B corresponds to the front of the burner unit A.

The flame hole plate 2 is made of metal having excellent heat resistance (for example, stainless steel), and a plurality of flame holes 20 penetrating in the thickness direction of the flame hole plate 2 is provided. The frame-shaped base 1 and the distribution plate 3 are also made of metal such as stainless steel. The plurality of flame holes 20 are holes for passing a mixed gas of fuel gas and air supplied to the back surface side of the flame hole plate 2 and burning the fuel gas on the front surface side of the flame hole plate 2. For example, in the flame hole plate 2 of FIG. 1, a plurality of flame holes 20 are provided in an appropriate array in the area Sa marked with a halftone dot pattern. The plurality of flame holes 20 can be provided in various modes such as a round hole, a rectangular hole, or a combination of both.

The frame-shaped base 1 serves as a support member and a cover member for the flame hole plate 2, and a frame-shaped front wall portion 10 that abuts in the vicinity of the outer peripheral portion of the surface portion of the flame hole plate 2, and the front wall portion 10. A standing wall portion 11 standing upright from the rear side and a flange portion 12 continuous with a rear end portion of the standing wall portion 11 are provided. The standing wall portion 11 has a loop shape that is substantially rectangular in a front view and surrounds the outer peripheral portion of the flame hole plate 2. The standing wall portion 11 has a width that is wider than the flame hole plate 2 in the vertical and horizontal directions in the front view of the burner unit A. Is enlarged by an appropriate size. As a result, a gap 4 for reducing stress at the time of thermal expansion of the flame hole plate 2 is formed between the standing wall portion 11 and the outer peripheral portion of the flame hole plate 2 over the entire circumference of the flame hole plate 2. Has been done. The width of the gap 4 is preferably such that, when the burner plate A is thermally burned in the burner unit A and the flame hole plate 2 is thermally expanded (width and width are increased), the outer peripheral portion of the flame hole plate 2 is raised by the standing wall portion 11. It is a size that can avoid a strong contact with.
As shown in FIG. 2, the flange portion 12 of the frame-shaped base 1 is fastened to the flange portion 50 of the burner case 5 using, for example, bolts and nuts 6 and 6a.

The distribution plate 3 is a plate provided with a plurality of distribution holes 30 for rectifying a mixed gas of fuel gas and air supplied from the back side thereof and guiding the mixed gas to the plurality of flame holes 20. In the distribution plate 3 shown in FIG. 1B, a plurality of distribution holes 30 are provided in an appropriate array in a region Sb marked with a halftone dot pattern. The distribution plate 3 is located behind the flame hole plate 2 and is fixed to the frame-shaped base 1 by welding its outer peripheral edge portion to the standing wall portion 11 of the frame-shaped base 1.
However, the distribution plate 3 is provided with a plurality of convex portions 31 that project toward the flame hole plate 2 side and contact the flame hole plate 2. As a result, the flame hole plate 2 is sandwiched and held between the plurality of convex portions 31 and the front wall portion 10 of the frame-shaped base 1.

The flame hole plate 2 is not welded to the frame-shaped base 1 and the distribution plate 3 and is in a non-bonded state. A space 7 is formed between the general portion of the distribution plate 3 (a portion other than the convex portion 31) and the flame hole plate 2. The plurality of convex portions 31 are formed by pressing the distribution plate 3, and preferably, the flame holes 20 are avoided so as not to close the flame holes 20 in the flame hole plate 2. It is provided in the arrangement.

Next, the operation of the burner unit A described above will be described.

First, since the flame hole plate 2 is made of metal, it is possible to reduce the raw material cost and reduce the manufacturing cost of the burner unit A as a whole.
On the other hand, when the burner unit A is used to burn the fuel gas, the flame hole plate 2 is exposed to the flame and heated to a high temperature, so that thermal expansion occurs and the vertical and horizontal widths thereof increase. On the other hand, in this embodiment, since the stress reducing gap 4 is formed on the outer periphery of the flame hole plate 2, when the flame hole plate 2 is thermally expanded, the outer periphery of the flame hole plate 2 is increased. The portion is prevented or suppressed from strongly abutting against the upright wall portion 11 of the frame-shaped base 1, and a large thermal stress does not occur in the flame hole plate 2. Therefore, it is possible to prevent the flame hole plate 2 from being damaged such as cracks due to the thermal stress.

In addition, as described above, the flame hole plate 2 is not joined to both the frame-shaped base 1 and the distribution plate 3, and the front wall portion 10 of the frame-shaped base 1 and the plurality of distribution plates 3 are connected to each other. Since the flame hole plate 2 is sandwiched and held between the convex portion 31 and the convex portion 31, thermal stress is less likely to occur in the flame hole plate 2 when the flame hole plate 2 thermally expands in the vertical width direction and the horizontal width direction. The effect is obtained. Further, when manufacturing the burner unit A, the step of welding the flame hole plate 2 to the frame-shaped base 1 is not necessary, which also makes it possible to reduce the manufacturing cost. Further, since the plurality of convex portions 31 of the distribution plate 3 form the space 7 between the distribution plate 3 and the flame hole plate 2, a dedicated spacer for forming the space 7 is separately provided. It is also possible to eliminate the need to provide.

3 to 5 show another embodiment of the present invention. In these figures, elements that are the same as or similar to those in the above-described embodiment will be assigned the same reference numerals as in the above-described embodiment, and redundant description will be omitted.

In the burner unit Aa shown in FIG. 3, a positioning hole portion 25 is provided in, for example, substantially the central portion of the flame hole plate 2. On the other hand, the distribution plate 3 is provided with a positioning projection 35 whose tip is fitted into the positioning hole 25. Only one positioning hole 25 and one positioning protrusion 35 are provided. The positioning protrusions 35 can be formed by pressing the distribution plate 3 in the same manner as the convex portions 31.

With such a configuration, it is possible to prevent the flame hole plate 2 from being unduly displaced in both the vertical and horizontal directions. On the other hand, the structure in which the positioning holes 25 and the positioning protrusions 35 are engaged one by one does not cause thermal stress when the flame hole plate 2 is thermally expanded.
Although the positioning hole 25 is configured to penetrate the flame hole plate 2, instead of this, a positioning recess that does not penetrate the flame hole plate 2 is provided, and the positioning projection 35 is provided in the positioning recess 35. It is also possible to adopt a configuration in which This also applies to the embodiment shown in FIG. 4 described later.

In the burner unit Ab shown in FIG. 4, a plurality of (for example, two) positioning hole portions 25 are provided in the flame hole plate 2 at, for example, a substantially central portion in a position close to each other. Corresponding to this, the distribution plate 3 is provided with the same number of positioning protrusions 35 as those arranged close to each other.

With such a configuration, the flame hole plate 2 can be prevented from being displaced in both the vertical and horizontal directions, and the flame hole plate 2 rotates in a front view (corresponding to a plan view in FIG. 4 ). It can also be prevented. On the other hand, although a plurality of positioning holes 25 and a plurality of positioning projections 35 are provided, they are close to each other and the relative displacement amount when the flame hole plate 2 undergoes thermal expansion is small. It is possible to prevent the flame hole plate 2 from causing a large stress.

In the burner unit Ac shown in FIG. 5, the distribution plate 3 is provided with an extending portion 36 that overlaps the flange portion 12 of the frame-shaped base 1. The extension portion 36 and the flange portion 12 are fastened (jointly fastened) to the flange portion 50 of the burner case 5 using common bolts and nuts 6 and 6a (corresponding to fastening members in the present invention). The flange portion 50 corresponds to a specific example of "a burner unit attachment target portion" according to the present invention.

According to such a configuration, the configuration is rational as compared with the mounting structure of the burner unit A shown in FIG. 2, and it is not necessary to join the distribution plate 3 to the frame-shaped base 1. Therefore, it is more advantageous in reducing the manufacturing costs of the burner unit A and the combustion apparatus using the burner unit A.
The bolts and nuts 6 and 6a described above correspond to an example of a fastening member according to the present invention. However, the fastening member may be a screw fastening member, a caulking member, or the like, and instead of the fastening member, Attachment using a welded portion can also be achieved.

FIG. 6 shows an example of a hot water device WH configured using the burner unit A described above.
The hot water device WH includes a plurality of heat transfer tubes 9A and 9B for heating hot water, and a heat exchanger HE having a can body 8 accommodating the heat transfer tubes 9A and 9B. The burner unit A is mounted on the can body 8 after being turned upside down from the orientation shown in FIGS. 1A and 2A and 2B. The heat transfer tube 9A is a so-called body pipe, and is arranged along the inner peripheral surface of the can body 8. The heat transfer tubes 9B penetrate the heat absorbing fins 90 and are arranged substantially horizontally. The hot water supplied from the outside to the water inlet 91a on one end side of the heat transfer tube 9A flows through the heat transfer tube 9A as indicated by arrows N1 to N1 in FIG.
After flowing through the path indicated by N4, it reaches the heat transfer tube 9B, and flows through this heat transfer tube 9B through the path indicated by arrows N5 to N7 to reach the hot water outlet 91b and discharges the hot water. In such a process, the hot water is heated by the combustion gas generated by the burner unit A.
In the hot water device WH, the burner unit A is of a so-called reverse combustion system, and the mixed gas of the fuel gas and the air is supplied downward from a fan (not shown), so that the lower surface side of the flame hole plate 2 receives the fuel. The combustion region is reached, and the combustion gas is caused to proceed downward into the heat exchanger HE.

The present invention is not limited to the contents of the above-mentioned embodiment. The specific configurations of the burner unit and each part of the hot water device according to the present invention can be modified in various ways within the scope intended by the present invention.
The flame hole plate is made of metal, but may be made of a material other than stainless steel. The specific configuration of the flame hole is not limited. It is desirable that the stress reducing gap in the present invention is formed to have a width equal to or larger than the expanded width of the flame hole plate during thermal expansion of the flame hole plate.
The hot water apparatus WH shown in FIG. 6 is of a reverse combustion type, but the present invention is not limited to this, and for example, a heat exchanger is arranged on the upper side of the burner unit, and the combustion gas proceeds upward from the burner unit. Needless to say, it is also possible to use a positive combustion method. The specific configuration of the heat exchanger that constitutes the hot water device is not limited.

A, Aa to Ac Burner unit WH Water heater HE Heat exchanger 9A, 9B Heat transfer tube 1 Frame-shaped base 10 Front wall portion 11 Standing wall portion 12 Flange portion 2 Flame hole plate 20 Flame hole 25 Positioning hole portion 3 Distribution plate 31 convex portion 35 positioning protrusion 36 extended portion 4 stress reducing gap 50 flange portion of burner case (burner unit attachment target portion)
6,6a Bolts and nuts (fastening members)

Claims (5)

A flame hole plate provided with a plurality of flame holes,
A frame-shaped front wall portion that abuts in the vicinity of the outer peripheral portion of the surface portion of the flame hole plate, and a frame having an upright wall portion that stands up from the front wall portion to the back side thereof and surrounds the outer peripheral portion of the flame hole plate. Shape base,
A burner unit equipped with
The flame hole plate is made of metal, and a gap for reducing stress during thermal expansion of the flame hole plate is formed between the outer peripheral portion of the flame hole plate and the standing wall portion. A burner unit characterized by the above. The burner unit according to claim 1, wherein
Further provided is a distribution plate having air permeability, which is arranged on the back side of the flame hole plate so as to face the flame hole plate, and which is fixed to the frame-shaped base,
The distribution plate is provided with a plurality of convex portions that protrude toward the flame hole plate side and contact the flame hole plate,
The flame hole plate is held by being sandwiched and held between the plurality of convex portions and the front wall portion in a state where the frame-shaped base and the distribution plate are not joined. unit. The burner unit according to claim 2, wherein
The flame hole plate is provided with at least one positioning hole or positioning recess,
The burner unit, wherein the distribution plate is provided with one positioning protrusion that enters the positioning hole or the positioning recess, or a plurality of positioning protrusions that are arranged close to each other. The burner unit according to claim 2 or 3, wherein
A flange portion is continuously provided on the standing wall portion of the frame-shaped base,
The distribution plate is provided with an extending portion overlapping the flange portion, and the extending portion and the flange portion are attached to a burner unit attachment target portion via a common fastening member or a welding portion. There is a burner unit. A burner unit according to any one of claims 1 to 4,
A heat exchanger capable of heating hot water by recovering heat from combustion gas generated using this burner unit,
A hot water device comprising:

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