JP7198431B2 - Burner unit and water heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a burner unit used as a component of a combustion apparatus that burns fuel gas, and a water heater provided with the same.

As a specific example of the burner unit, there is one in which a burner hole plate provided with a plurality of burner holes is fixed to a frame-shaped base. The plurality of flame holes allow the mixed gas of fuel gas and air supplied from the rear side of the flame hole plate to pass through to the front side of the flame hole plate, and the front side area forms a combustion area for the fuel gas. It is a hole for forming. The frame-shaped base has a frame-shaped front wall that abuts near the outer periphery of the surface of the burner hole plate, and an upright wall that rises from the front wall toward the back side and surrounds the outer periphery of the burner hole plate. have.
Here, the flame hole plate is required to have excellent heat resistance because it is exposed to flames. Therefore, in the past, there is a fact that a ceramic plate is used as a raw material for the burner hole plate.

However, using a ceramic plate as a raw material for the flame hole plate increases the cost of parts.
As a means to solve this problem, it is conceivable to make the flame hole plate made of metal such as stainless steel, which has excellent heat resistance. Therefore, a large thermal stress is generated when the burner hole plate thermally expands. If this thermal stress increases, there is a concern that damage such as cracks may occur in the burner hole plate.

Japanese Patent No. 6378784 JP 2018-151121 A

The present invention has been conceived under the circumstances described above, and is capable of reducing the manufacturing cost and, moreover, appropriately eliminating the problem of damage due to the occurrence of large thermal stress in the burner hole plate. An object of the present invention is to provide a burner unit that can be eliminated and a water heater equipped with the same.

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

The burner unit provided by the first aspect of the present invention includes a burner hole plate provided with a plurality of burner holes, a frame-shaped front wall portion abutting near the outer periphery of the surface of the burner hole plate, and a frame-shaped base having an upright wall portion that rises from the front wall portion on the back side thereof and surrounds the outer peripheral portion of the burner unit, wherein the burner unit is made of metal and a gap for reducing stress during thermal expansion of the burner hole plate is formed between the outer peripheral portion of the burner hole plate and the upright wall portion. The air-permeable distribution plate is arranged on the back side of the frame-shaped base in such a manner as to be fixed to the frame-shaped base. The burner hole plate is provided with a plurality of convex portions that abut against the burner hole plate, and the burner hole plate is not connected to the frame-shaped base and the distribution plate, and is in contact with the plurality of convex portions. The flame hole plate is provided with at least one positioning hole or positioning recess, and the distribution plate is provided with the positioning hole. It is characterized in that there is one positioning projection that enters the hole or the positioning recess, or a plurality of positioning projections that are arranged close to each other .

According to such a configuration, the following effects are obtained.
That is, since the burner hole plate is made of metal, it is possible to reduce the component cost and the overall manufacturing cost as compared with the conventional technology using the ceramic plate. On the other hand, a gap is provided between the outer peripheral portion of the burner hole plate and the upright wall portion of the frame-shaped base to reduce stress when the burner hole plate thermally expands. In this case, the burner hole plate is prevented from coming into strong pressure contact with the upstanding wall portion of the frame-shaped base, thereby preventing the burner hole plate from being subjected to a large thermal stress. Therefore, it is possible to eliminate the possibility that the burner hole plate is damaged due to thermal stress.

According to such a configuration, the following effects are also obtained.
First, the flame hole plate is sandwiched and held between the frame-shaped base and the plurality of projections of the distribution plate in a state in which it is not joined to the frame-shaped base and the distribution plate. When the burner hole plate thermally expands, it becomes possible to smoothly deform the burner hole plate in the direction crossing the pinching direction (vertical and horizontal width directions of the burner hole plate). As a result, thermal stress can be made less likely to occur in the burner 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 terms of reducing the manufacturing cost.
Third, the plurality of convex portions of the distribution plate also serve as spacers that form spaces between the distribution plate and the burner hole plate. Therefore, there is no need to separately provide a dedicated member for forming a space between the distribution plate and the burner port plate, which can further reduce the manufacturing cost.

With such a configuration, the position of the burner hole plate can be further improved, and the position of the burner hole plate is unstable due to the stress reduction gaps formed around the outer circumference of the burner hole plate. It is possible to appropriately prevent it from becoming When a plurality of positioning projections are provided, it is also possible to prevent the burner hole plate from rotating. On the other hand, according to a configuration in which only one positioning projection is provided or a configuration in which a plurality of positioning projections are provided close to each other, when the burner hole plate thermally expands, contact with the positioning projection causes Little or no thermal stress may occur.

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

According to such a configuration, the mounting portion of the distribution plate to the frame-shaped base and the mounting portion of the frame-shaped base to the target mounting portion for the burner unit are integrated, thereby rationalizing and simplifying the structure. Therefore, it is more preferable for reducing the manufacturing cost.

The water heater provided by the second aspect of the present invention heats hot water 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

With such a configuration, the same effects as 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 clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

(a) is a schematic perspective view showing an example of a burner unit, and (b) is an exploded schematic perspective view of the burner unit shown in (a). (a) is a cross-sectional view along IIa-IIa in FIG. 1(a), and (b) is a partially enlarged cross-sectional view of (a). It is a sectional view showing an example of a burner unit concerning the present invention. FIG. 4 is a cross-sectional view showing another example of the present invention; FIG. 10 is an enlarged cross-sectional view of a main part showing another example of the present invention; FIG. 2 is a schematic cross-sectional view showing an example of a water heater using the burner unit shown in FIG. 1;

Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

A burner unit A shown in FIGS. 1 and 2 includes a frame-shaped base 1 , a burner hole plate 2 and a distribution plate 3 .
In addition, let the left side of FIG.1(b) be the front of the burner unit A in this embodiment. 1(a), 2(a) and 2(b) corresponds to the front of the burner unit A. FIG.

The burner hole plate 2 is made of a metal (for example, stainless steel) having excellent heat resistance, and is provided with a plurality of burner holes 20 penetrating in the thickness direction of the burner hole plate 2 . 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 allowing the mixed gas of fuel gas and air supplied to the back side of the flame hole plate 2 to pass therethrough and for burning the fuel gas on the 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 arrangement in the halftone dot region Sa. The plurality of flame holes 20 can be provided in various forms such as round holes, rectangular holes, or a combination of both.

The frame-shaped base 1 serves as a support member and a cover member for the burner hole plate 2, and has a frame-shaped front wall portion 10 that abuts near the outer periphery of the surface portion of the burner hole plate 2. It has an upright wall portion 11 standing upright on the rear side and a flange portion 12 connected to the rear end portion of the upright wall portion 11 . The upright wall portion 11 has a substantially rectangular loop shape in a front view that surrounds the outer peripheral portion of the burner hole plate 2 . is enlarged by a modest dimension. As a result, a gap 4 for reducing stress during thermal expansion of the burner hole plate 2 is formed over the entire circumference of the burner hole plate 2 between the upright wall portion 11 and the outer peripheral portion of the burner hole plate 2 . It is The width of the gap 4 is preferably such that when the burner unit A burns the fuel gas, the outer peripheral portion of the burner hole plate 2 becomes the upright wall portion 11 when the burner hole plate 2 thermally expands (the vertical and horizontal widths expand). It is a dimension that can avoid 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 the mixed gas of fuel gas and air supplied from the rear thereof and guiding it to the plurality of flame holes 20 . In the distribution plate 3 shown in FIG. 1(b), a plurality of distribution holes 30 are provided in an appropriate arrangement in the halftone dot region Sb. The distribution plate 3 is positioned behind the burner hole plate 2 and is fixed to the frame-shaped base 1 by welding its outer peripheral portion to the upright wall portion 11 of the frame-shaped base 1 .
However, the distribution plate 3 is provided with a plurality of convex portions 31 that protrude toward the burner hole plate 2 side and contact the burner hole plate 2 . As a result, the burner 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 .

Note that the flame hole plate 2 is in a non-bonded state in which it is not welded to the frame-shaped base 1 and the distribution plate 3 . A space 7 is formed between the general portion of the distribution plate 3 (the portion other than the convex portion 31) and the burner port plate 2. As shown in FIG. The plurality of convex portions 31 are formed by pressing the distribution plate 3, and preferably avoid the burner holes 20 of the burner hole plate 2 so as not to block the burner holes 20. Placement.

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

First, since the burner hole plate 2 is made of metal, it is possible to reduce the raw material cost and reduce the overall manufacturing cost of the burner unit A.
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 it undergoes thermal expansion and expands in width and width. On the other hand, in this embodiment, since the gap 4 for stress reduction is formed in the outer circumference of the burner hole plate 2, when the burner hole plate 2 thermally expands, the outer circumference of the burner hole plate 2 is prevented or suppressed from coming into strong contact with the upright wall portion 11 of the frame-shaped base 1, and large thermal stress does not occur in the burner hole plate 2. Therefore, it is possible to prevent damage such as cracks from occurring in the burner hole plate 2 due to thermal stress.

Further, 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 distribution plate 3 are separated from each other. Since it is sandwiched and held between the convex portions 31, thermal stress is less likely to occur in the burner hole plate 2 when the burner hole plate 2 thermally expands in the vertical and horizontal directions. effect to be obtained. In addition, when manufacturing the burner unit A, the process of welding the burner hole plate 2 to the frame-shaped base 1 is not necessary, so that the manufacturing cost can be reduced. Furthermore, since the plurality of convex portions 31 of the distribution plate 3 form the space 7 between the distribution plate 3 and the burner port plate 2, a dedicated spacer for forming the space 7 is separately provided. It is also possible to eliminate the need to provide

3-5 illustrate embodiments of the present invention. In these figures, elements that are the same as or similar to those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and repeated explanations are omitted.

In the burner unit Aa shown in FIG. 3, a positioning hole 25 is provided in, for example, a substantially central portion of the burner hole plate 2. As shown in FIG. 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 projection 35 are provided. The positioning projections 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 burn hole plate 2 from being unduly displaced in both the vertical and horizontal directions. On the other hand, the structure in which each of the positioning holes 25 and the positioning projections 35 is engaged with each other does not cause thermal stress when the burner hole plate 2 thermally expands.
Although the positioning holes 25 pass through the burner hole plate 2, instead of this, a positioning recess that does not pass through the burner hole plate 2 is provided. It is also possible to have a configuration in which the This also applies to the embodiment shown in FIG. 4, which will be described later.

In the burner unit Ab shown in FIG. 4, a plurality of (for example, two) positioning holes 25 are provided in close proximity to each other, for example, in a substantially central portion of the burner hole plate 2 . Correspondingly, the distribution plate 3 is provided with the same number of positioning projections 35 arranged close to each other.

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

In the burner unit Ac shown in FIG. 5, the distribution plate 3 is provided with an extension portion 36 overlapping the flange portion 12 of the frame-shaped base 1 . The extension portion 36 and the flange portion 12 are fastened (co-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 the "part to be attached for the burner unit" in the present invention.

According to such a structure, the structure is rational compared with the mounting structure of the burner unit A shown in FIG. Therefore, it is more advantageous in reducing the manufacturing cost of the burner unit A and the combustion apparatus using it.
The bolts and nuts 6 and 6a described above correspond to an example of the fastening member according to the present invention, but the fastening member may also be a screw fastening member or a crimping member. Attachment using welds can also be attempted.

FIG. 6 shows an example of a water heater WH constructed using the burner unit A described above.
This water heater WH comprises a plurality of heat transfer tubes 9A, 9B for heating hot water, and a heat exchanger HE having a can body 8 containing these. The burner unit A is mounted on the can body 8 after being turned upside down from the orientation shown in FIGS. 1(a) and 2(a) and (b). 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 are arranged substantially horizontally through the heat absorbing fins 90 . 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 through the arrows N1 to 6 in FIG.
After flowing along the path indicated by N4, it reaches the heat transfer tube 9B, flows through this heat transfer tube 9B along the paths indicated by arrows N5 to N7, reaches the outlet 91b, and is discharged. In this process, the hot water is heated by the combustion gas generated by the burner unit A.
In this water heater WH, the burner unit A is of a so-called reverse combustion type, and a mixed gas of fuel gas and air is supplied downward from a fan (not shown), so that the lower surface of the burner hole plate 2 is filled with fuel. It serves as a combustion zone and directs the combustion gases downward into the heat exchanger HE.

The invention is not limited to the content of the embodiments described above. The specific configuration of each part of the burner unit and the water heater according to the present invention can be changed in various ways within the intended scope of the present invention.
Although the flame hole plate is made of metal, it may be made of a material other than stainless steel. The specific configuration of the flame hole is not limited. It is desired that the stress-reducing gaps in the present invention have a width equal to or greater than the expanded width of the burner hole plate when the burner hole plate thermally expands.
The water heater WH shown in FIG. 6 is of a reverse combustion type, but the present invention is not limited to this. Needless to say, it is also possible to adopt a positive combustion system. The specific configuration of the heat exchanger that constitutes the water heater is also 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 11 Upright wall 12 Flange 2 Burner hole plate 20 Burner hole 25 Positioning hole 3 Distribution plate 31 convex portion 35 positioning projection 36 extension portion 4 gap for stress reduction 50 flange portion of burner case (part to be installed for burner unit)
6, 6a bolts and nuts (fastening members)

Claims (3)

a flame hole plate provided with a plurality of flame holes;
A frame having a frame-shaped front wall portion abutting near the outer peripheral portion of the surface portion of the burner hole plate, and a standing wall portion rising from the front wall portion toward the back side and surrounding the outer peripheral portion of the burner hole plate. a shaped base;
A burner unit comprising
The burner hole plate is made of metal, and a gap for reducing stress during thermal expansion of the burner hole plate is formed between the outer peripheral portion of the burner hole plate and the upright wall portion. ,
a ventilation distribution plate arranged on the rear 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 burner hole plate and contact the burner hole plate,
The flame hole plate is sandwiched and held between the plurality of convex portions and the front wall portion in a state in which the flame hole plate is not joined to the frame-shaped base and the distribution plate,
The flame hole plate is provided with at least one positioning hole or positioning recess,
A burner unit , wherein said distribution plate is provided with one positioning projection that enters said positioning hole or positioning recess, or a plurality of positioning projections arranged close to each other . A burner unit according to claim 1,
A flange portion is connected to the standing wall portion of the frame-shaped base,
The distribution plate is provided with an extension portion that overlaps the flange portion, and the extension portion and the flange portion are attached to the burner unit attachment target portion via a common fastening member or welded portion. There is a burner unit. A burner unit according to claim 1 or 2 ;
a heat exchanger capable of heating hot water by recovering heat from the combustion gas generated by the burner unit;
A water heater, characterized by comprising:

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