JP2007225267A - Combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a combustor capable of generating stable primary flame by improving the compustor for two-stage combustion. <P>SOLUTION: This combustor 1 has a premix member 2, a flame hole member 3 and air flow members 5. The premix member 2 is engaged with the flame hole member 3 to constitute one intermediate member 6, and the intermediate member 6 is sandwiched between the two air flow members 5. Stabilized flame forming walls 26 are fixed on side walls 31, 32 of a body member 25 of the flame hole member 3, and a sideface flame hole 27 is formed therein. A step (fall part) 120 between the top face of a main flame hole 121 of the flame hole member 3, and the side wall parts 31, 32, and stabilized flame 123 is generated in a position separated from the main flame 125 of the first flame. The stabilized flame 123 flows toward the step 120 to reach a base of the main flame 125 of the first flame, but an amount converged with the main flame 125 of the first flame is small not to extend excessively the length of the main flame 125 of the first flame. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a combustion apparatus, and more particularly to a combustion apparatus recommended for use in a water heater or a bath apparatus.

Combustion devices are main components of water heaters and bath devices, and are widely used not only in factories but also in general households.
In recent years, environmental destruction caused by acid rain has become a serious social problem, and there is an urgent need to reduce the total amount of NOx (nitrogen oxide) emissions.
There is a combustion apparatus that employs a combustion method called a concentration combustion method as a configuration that can be employed in a small device such as a hot water supply device and that can suppress the amount of NOx generated.
In the lean combustion method, the main flame is generated from a dilute gas mixture that is premixed with about 1.6 times the theoretical air volume in the fuel gas, and there is little air mixing in the vicinity of the main flame. A flame holder generated from a mixed gas having a high concentration is arranged.
For example, Patent Documents 1 and 2 disclose a combustion apparatus that uses light and shade combustion.

In addition, there is another combustion method called a two-stage combustion method as a combustion method that generates little NOx. The two-stage combustion method is a combustion type in which fuel gas is injected in a state where oxygen is insufficient, the gas is ignited to generate a primary flame, and secondary air is supplied to unburned gas to generate a secondary flame. is there.
A combustion apparatus employing a two-stage combustion method is disclosed in Patent Document 3.
Japanese Patent Laid-Open No. 5-118516 JP-A-6-126788 JP-A-52-143524

A combustion apparatus that employs the lean combustion method has a small amount of NOx generated and is well-received in the market, but has a drawback of a small turn-down ratio (Turn Down Ratio TDR). In particular, a combustion apparatus that employs the light and dark combustion method has a drawback that it is difficult to burn in a region where the calorific value is small.
That is, in the lean combustion method, as described above, the main flame is generated from a lean mixed gas obtained by premixing the fuel gas with about 1.6 times the theoretical air amount. Although this mixed gas is lean, its combustion speed is slow.

  By the way, the combustion apparatus which employs the light and dark combustion method includes a blower for generating a lean mixed gas. However, the blower has been used for many years, and the amount of blown air gradually decreases as the blower ages. The amount of air flow may be reduced due to clogging of the filter. Thus, when the amount of blast decreases due to secular change, the amount of air of the mixed gas that forms the main flame tends to decrease, and the amount of air to be mixed approaches the theoretical amount of air. As a result, the combustion speed of the main flame tends to be accelerated by secular change, and the base end portion of the flame gradually approaches the flame hole due to secular change. Therefore, when burning in a region where the heat generation amount is small, the base end portion of the flame approaches the flame hole and damages the flame hole. Therefore, a combustion apparatus that employs the light and dark combustion method must limit combustion in a region where the calorific value is small in anticipation of secular change.

In addition, the lean combustion method is unsatisfactory because the range of usable gases is narrow. That is, the fuel gas supplied by the gas manufacturer may be composed of only a single component, but in many cases, a fuel gas of a plurality of components is mixed. For this reason, even if the amount of heat generated (the amount of heat per unit volume) is the same, the combustion rate differs for each fuel gas manufacturer.
On the other hand, in the light / dark combustion method, the main flame is burned in an excess air state, so that the fuel gas having a low combustion speed is burned out and cannot be burned stably.

  On the other hand, when the two-stage combustion method is employed, the turndown ratio can be increased as compared with the case where the concentration combustion method is employed. There are also a wide variety of applicable fuel gases. However, in the two-stage combustion method, the combustion state is unstable because the fuel gas is burned in a state where oxygen is insufficient. For this reason, there are no commercially available hot water heaters that employ the two-stage combustion method.

  Therefore, the present invention focuses on the above-mentioned problems of the prior art, and improves the combustion apparatus that performs the two-stage combustion, and aims to develop a combustion apparatus that generates a stable primary flame.

  The invention according to claim 1 for solving the above-described problem includes a flame hole member and an air flow path member, and the air flow path member has a wall shape and has an air discharge opening on the tip side. The flame hole member is disposed between the two air flow path members or between the air flow path member and another wall surface, and the first combustion portion is formed by a space surrounded by the flame hole member and the air flow path member. A combustion apparatus is formed and oxygen-deficient fuel gas is discharged from the flame hole member to the first combustion part and burns, and further burns by receiving air supply from the air discharge opening of the air flow path member, The hole member has a main body member and a flame-holding wall, the main body member has a top surface portion and a side wall portion, and a main flame hole is provided in the top surface portion of the main body member. There is a drop between the side wall and the flame-holding wall is provided on the side of the main body. The position of the projecting end of the flame holding wall in the direction is on the upstream side of the boundary between the head part and the top surface part, and a gap is provided between the side wall part of the main body part and the flame holding wall. The combustion apparatus is characterized in that a side flame hole is formed, fuel gas is also released from the side-side flame hole, and air flows in the vicinity of the side-side flame hole of the flame hole member.

In the combustion apparatus of the present invention, fuel gas in an oxygen-deficient state is discharged from the flame hole member to the first combustion portion and burned, and further burned by receiving supply of air from the air discharge opening of the air flow path member. Two-stage combustion is performed.
And in the combustion apparatus of this invention, it has a side flame hole other than the main flame hole, and fuel gas is discharge | released also from a side flame hole. Then, air is separately supplied to the side-side flame holes. Therefore, a stable flame is generated in the side-side flame hole, and the base end portion of the primary flame is held.
In the combustion apparatus of the present invention, there is a drop portion between the top surface portion of the main body portion and the side wall portion of the main body portion. In the combustion apparatus of the present invention, the side-side flame hole is formed by the flame-holding wall, and the position of the projecting end of the flame-holding wall is upstream of the boundary between the head part and the top part.
Therefore, the flame (flame holding) generated from the side-side flame hole is generated on the upstream side of the main flame and hardly merges with the main flame. Therefore, in the combustion apparatus of the present invention, the primary flame is not excessively long.
This operation will be described in detail as follows.
That is, as described above, in the two-stage combustion method, the combustion state is unstable because the fuel gas is burned in a state where oxygen is insufficient. Therefore, the present inventors considered that a flame holding was formed at the base end portion of the primary flame and the base end portion of the primary flame was not held.
Therefore, as shown in FIG. 35, a flame holding wall 202 is provided in the main body 201 of the flame hole member 200, and fuel gas (from the gap 206 formed between the flame holding wall 202 and the side surface 203 of the main body 201 is also included. The broken arrows in the drawing were released, and air was supplied in the vicinity of the flame-holding wall 202. Further, the height of the projecting end portion of the flame holding wall 202 was made higher than the height of the main flame hole 207 as shown in FIG.
The reason for this is based on experience in manufacturing a combustion apparatus that employs light and shade combustion. In other words, in the light / dark combustion technique, since the flame holding is to hold the base end portion of the main flame, it has been considered desirable that the flame holding be generated in the vicinity of the main flame. Therefore, as described above, it has been considered desirable to make the height of the projecting end portion of the flame-holding wall 202 higher than the height of the main flame hole 207.
However, when this technique was applied to the two-stage combustion method, it was found that the flame holding 210 merged with the main flame 208 and the full length of the flame would be excessively extended.
In other words, it was found that when the two-stage combustion method is adopted, it is better to generate the flame holding position at a position somewhat away from the main flame, contrary to the common sense of the concentration combustion method.
Therefore, in the present invention, a drop portion is provided between the top surface portion of the main body portion and the side wall portion of the main body portion, and the position of the protruding end portion of the flame-holding wall is located upstream of the boundary between the drop portion and the top surface portion. placed.
Therefore, the flame (flame holding) generated from the side-side flame hole is generated at a position away from the main flame to some extent, and is difficult to merge with the main flame. Therefore, in the combustion apparatus of the present invention, the primary flame is not excessively long.

  The invention according to claim 2 includes a flame hole member and an air flow path member, and the air flow path member has a wall shape and has an air discharge opening on the tip side, and the flame hole member has two sheets. An oxygen-deficient fuel is formed between the air flow path members or between the air flow path member and another wall surface, and a first combustion portion is formed by a space surrounded by the flame hole member and the air flow path member. A combustion apparatus in which gas is discharged from the flame hole member to the first combustion portion and burns, and further burns by receiving supply of air from the air discharge opening of the air flow path member. The main body member has a top surface portion and a side wall portion, a main flame hole is provided in the top surface portion of the main body member, and between the top surface portion of the main body portion and the side wall portion of the main body portion. Has a drop head, and the flame holding wall is provided on the side surface of the main body, and the flame holding wall in the flow direction of the fuel gas. The position of the end portion is upstream of the boundary between the head portion and the side wall portion, and a gap is provided between the side wall portion of the main body portion and the flame-holding wall to form a side-side flame hole. The combustion apparatus is characterized in that fuel gas is also released from the side flame holes, and further air flows in the vicinity of the side-side flame holes of the flame hole member.

According to the combustion apparatus of the present invention, the flame holding position is further separated from the main flame.
That is, in the combustion apparatus of the present invention, the position of the projecting end portion of the flame holding wall in the fuel gas flow direction is upstream of the boundary between the drop portion and the side wall portion. Therefore, the flame (flame holding) generated from the side-side flame hole is difficult to merge with the main flame, and the primary flame does not become excessively long.

  The invention according to claim 3 is the combustion apparatus according to claim 1 or 2, wherein the drop portion is a step or an inclined surface.

  The head part is provided mainly for the purpose of separating the main flame from the flame holding, and may be a step or an inclined surface. However, according to experiments conducted by the present inventors, the step was easier to prevent the flame holding and the main flame from being combined than the inclined surface.

  The invention according to claim 4 is characterized in that the flow rate of the fuel gas released from the side-side flame hole is slower than the flow rate of the fuel gas released from the main flame hole provided in the main body member. It is a combustion apparatus in any one of thru | or 3.

  In the above-described configuration, the flow rate of the fuel gas released from the side-side flame hole is slower than the flow rate of the fuel gas released from the main flame hole, so that the flame generated in the side-side flame hole is less likely to fly. The fuel gas discharged from the side-side flame hole stably burns in a state close to complete combustion, and holds the base end portion of the primary flame. As a result, the primary flame is stabilized.

  The invention according to claim 5 has a premixing member for premixing fuel gas and air inside, and the fuel gas and air premixed by the premixing member flow to the flame hole member, and The mixing member is provided with an introduction port through which fuel gas and air are introduced, a venturi portion communicating with the introduction port, and an enlarged portion and a throttle portion communicating with the venturi portion. It is a combustion apparatus in any one of thru | or 4.

  In the combustion apparatus of this invention, it has a premixing member and fuel gas and air are premixed in a premixing member. The premixing member includes an introduction port through which fuel gas and air are introduced, a venturi portion communicating with the introduction port, and an enlarged portion and a throttle portion communicating with the venturi portion are sequentially provided. Therefore, the fuel gas and air that have exited the venturi section are mixed in the expansion section and the throttle section. Therefore, according to the structure of the present invention, mixing of fuel and air is promoted, and the length from the inlet to the flame hole can be shortened. According to the configuration of the present invention, the mixed gas discharged from the flame holes is homogeneous because the fuel gas and air are well mixed. In the combustion apparatus of the present invention, the fuel gas that is uniformly adjusted is released from the entire region of the wall of the flame hole member, so that the primary flame and the secondary flame are generated in a well-balanced manner and over the entire combustion site. Spread evenly. Therefore, the noise is low.

  Further, according to experiments by the present inventors, stirring of fuel and air is promoted particularly when the inner wall at the boundary between the venturi portion and the enlarged portion has an opening angle of 45 ° to 90 ° with respect to the axis. (Claim 6).

  Similarly, according to the experiment, when the cross-sectional area of the largest portion of the enlarged portion is 1.2 to 3 times the cross-sectional area of the downstream end of the venturi portion, the agitation of fuel and air is particularly promoted. (Claim 7).

  It has also been found that when the cross-sectional area of the throttle portion is 0.4 to 0.8 times the cross-sectional area of the largest portion of the enlarged portion, the agitation of fuel and air is particularly promoted. ).

In the combustion apparatus of the present invention, stable flame holding is generated in the vicinity of the main primary flame, and the main primary flame is stabilized. For this reason, it is practical with less fire. In the combustion apparatus of the present invention, the length of the primary flame is not excessively long.
Furthermore, the combustion apparatus of the present invention generates less nitrogen oxide and can set a high turndown ratio. Furthermore, the combustion apparatus of the present invention is widely applicable to the combustion rate of the combustion gas, and does not select the type of gas.

  Examples of the present invention will be described below. FIG. 1 is a cross-sectional perspective view of a combustion apparatus schematically illustrating the structure of the combustion apparatus of the present invention. FIG. 2 is a cross-sectional view of the combustion apparatus schematically illustrating the structure near the flame hole member of the combustion apparatus of the present invention and the flow of fuel gas, air, and flame. 3 to 5 are cross-sectional views of the combustion apparatus schematically illustrating the structure near the flame hole member and the flow of fuel gas, air, and flame of the combustion apparatus of another embodiment of the present invention.

First, a schematic configuration and basic functions of the present invention will be described with reference to the schematic diagrams of FIGS. The embodiment of FIG. 1 conceptually illustrates the present invention.
In the following description, the vertical relationship is based on the posture in which the combustion apparatus 1 is placed vertically and a flame is generated on the upper side. The expressions on the upstream side and the downstream side are based on the flow of air or fuel gas. The width direction is a direction (in the direction of arrow W in the drawing) corresponding to the left-right direction with the largest area of the combustion device as the front.

  The combustion apparatus 1 of a present Example is used in parallel with a case, or is used independently. The combustion apparatus 1 of the present embodiment includes a premixing member 2, a flame hole member 3, and two air flow path members 5. In the combustion apparatus 1 of the present embodiment, the premixing member 2 and the flame hole member 3 are fitted together to form one intermediate member 6, and the intermediate member 6 is interposed between the two air flow path members 5. Although it is sandwiched, when actually used, it is said that the air flow path member 5, the intermediate member 6, the air flow path member 5, the intermediate member 6, the air flow path member 5. The premixing members 2 and the intermediate members 6 are alternately arranged to form a surface.

  The premixing member 2 that is a constituent member of the combustion apparatus 1 is a member that performs a function of premixing fuel gas and air inside. The premixing member 2 includes a mixing portion 7 having a curved path and an opening row portion 10 in which openings 8 are provided in a row. The opening row portion 10 is a portion in which a cavity having a substantially square cross section extends long and linearly.

The air flow path member 5 is a member having a thin wall shape. The air flow path member 5 is made of thin plates on the front and back surfaces 11 and 12, the front and back surfaces 11 and 12 are joined with a slight gap therebetween, and three sides other than the lower surface side are joined. A gap serving as an air flow path 13 is provided.
The air flow path member 5 folds a single plate to constitute the front and back surfaces 11 and 12, and has a bent portion 14 with an acute angle at the tip portion, and the bent portion 14 forms the top portion 9. The top portion 9 extends in a ridgeline shape.
On the other hand, on the base end side of the air flow path member 5, the space between the front and back surfaces 11 and 12 is opened, and an air introduction opening 15 is formed.

The air flow path member 5 has air discharge openings in three regions. As described above, since the premixing members 2 and the intermediate members 6 are alternately arranged to form a plane, the same number of plates are provided in the same portion on the front and back surfaces 11 and 12 of the air flow path member 5. An opening is provided.
The region where the air discharge opening is provided is roughly divided into a front end portion, a position facing the first combustion portion, and a position facing the intermediate member 6.

  That is, most of the plates of the front and back surfaces 11 and 12 of the air flow path member 5 are arranged in parallel, but only the tip portion is bent in a mountain shape, and the inclined surfaces 16 and 17 are formed on the front side and the back side. Is formed. A tip opening 20 is provided in the inclined surfaces 16 and 17. Further, a tip end opening 21 is also provided at the most distal portion (ridge line portion). The front end openings 20 and 21 are provided for supplying secondary air to the secondary flame.

  Further, the front and back surfaces 11 and 12 of the air flow path member 5 are formed such that the front-side air flow path 13 is narrower than the base end side as shown in FIG. There is a step in the part corresponding to. This step portion is also an inclined surface 22. The step portion is provided with an air discharge opening 23 for the combustion portion. The air discharge opening 23 for the combustion part supplies secondary air to the primary flame of the first combustion part 46 and burns a part of the primary flame to generate a secondary flame in a part of the first combustion part 46 It is.

  Further, an air discharge opening (upstream air discharge opening) 48 is also provided at a position facing the intermediate member 6. The air discharge opening (upstream air discharge opening) 48 supplies air to the side surface portion of the flame hole member 3 to stabilize flame holding.

The flame hole member 3 includes a main body member 25 and a flame holding wall 26. The main body member 25 of the flame hole member 3 is made by bending a single metal plate, and includes a top surface portion 30 that functions as a flame hole, a step portion (head portion) 120, and two side wall portions 31. , 32.
In the present embodiment, the top surface portion 30 is flat, and the two side wall portions 31 and 32 are both substantially perpendicular to the top surface portion 30.
And the step part 120 exists in the boundary part of the both ends of the top surface part 30, and the side wall parts 31 and 32. As shown in FIG.
The left and right sides of the flame hole member 3 are closed, and only the surface located on the lower side of the drawing is open. The top surface portion 30 of the flame hole member 3 is elongated and is elongated. On the top surface portion 30 of the main body member 25, slits to be the flame holes 33 are regularly arranged. The flame hole 33 provided in the main body member 25 functions as a “main flame hole”.
A bulging portion 34 bulging outward (in the thickness direction) is provided at an intermediate portion between the side wall portions 31 and 32. The bulging portion 34 is provided over the entire width of the flame hole member 3.

  The open end sides of the side walls 31 and 32 are folded back by about 90 ° twice as shown in the figure, and a fitting concave groove 38 is formed on the outside. The bottom wall 36 of the fitting groove 38 is perpendicular to the side walls 31, 32, and the outer wall 37 of the fitting groove 38 is parallel to the side walls 31, 32.

The flame holding wall 26 is attached to the main body member 25 as described above. The flame holding wall 26 is fixed to the side wall portions 31 and 32 of the main body member 25, and there is a gap 29 between the side wall portions 31 and 32 of the main body member 25. The gap 29 is open on the upper side of the drawing. This opening functions as a side-side flame hole 27.
The height of the flame-holding wall 26 is lower than the step portion 120 formed in the main body member 25. That is, the height of the projecting end 126 of the flame-holding wall 26 is upstream of the boundary 122 between the stepped portion (head portion) 120 and the side wall portions 31 and 32 with reference to the flow direction of the fuel gas as shown in FIG. is there.
An opening 35 is provided in the side wall portions 31 and 32 of the main body member 25 and faces the flame holding wall 26, and communicates the inner surface of the main body member 25 and the gap 29.

Next, the relationship between the members will be described.
In the present embodiment, as described above, the premixing member 2 and the flame hole member 3 are fitted together to constitute one intermediate member 6. More specifically, the opening row portion 10 of the premixing member 2 is inserted between the side wall portions 31 and 32 of the flame hole member 3. In the actual manufacturing process, the premixing member 2 is inserted through the opening (lower part of the drawing) between the side wall portions 31 and 32 of the flame hole member 3 to join them together.

The side wall portions 31 and 32 and the opening row portion 10 are partially in contact with each other by an uneven shape (not shown), and both are integrated. Since the side wall portions 31 and 32 and the opening row portion 10 are partially in contact with each other due to the concavo-convex shape as described above, in other words, the two are partially separated. The cross section of FIG. 1 illustrates a cross section at a portion where the side wall portions 31 and 32 and the opening row portion 10 are separated.
About the site | part corresponded to the bulging part 34 of the side wall parts 31 and 32, it is separated from the opening row | line | column part 10 included. The portion of the bulging portion 34 corresponds to the row portion of the opening 8 of the opening row portion 10. Therefore, the outside of the opening 8 of the opening row portion 10 is separated from the side wall portions 31 and 32, and there is a wider space (mixing space) 39 than others. This space communicates over a portion corresponding to all the openings 8.
There is a relatively large space 47 between the side wall portions 31 and 32 and between the top portion of the opening row portion 10 and the top surface portion 30 portion of the flame hole member 3. In the present embodiment, the flame hole upstream flow path 49 is formed by the mixing space 39 and the space 47 downstream of the opening row portion 10.

  Air flow path members 5 are mounted on both sides of the intermediate member 6. The air flow path member 5 is coupled to the intermediate member 6 by fitting the fitting concave groove 38 of the flame hole member 3 into the air introduction opening 15 on the proximal end side. That is, the outer wall 37 of the fitting groove 38 is inserted into the air introduction opening 15, and the projecting end of the air flow path member 5 is inserted into the fitting groove 38 and brought into contact with the bottom wall 36 of the fitting groove 38. .

  The air flow path member 5 and the intermediate member 6 (flame hole member 3) are partially in contact with each other by an uneven shape (not shown), and both are integrated. Since they are partially in contact with each other by the uneven shape as described above, in other words, they are partially apart. The cross section of FIG. 1 illustrates a portion where the air flow path member 5 and the intermediate member 6 (flame hole member 3) are separated so that the function can be easily understood. However, the gap 40 between the air flow path member 5 and the intermediate member 6 is blocked by the bottom wall 36 of the fitting concave groove 38 at the upstream end (the lower end in the drawing) of the combustion device 1. Therefore, the gap 40 between the air flow path member 5 and the intermediate member 6 does not directly communicate with the outside world on the base end side.

  As described above, the flame hole member 3 is located between the two air flow path members 5, but the top surface portion 30 of the flame hole member 3 is located on the lower side of the drawing relative to the air flow path member 5. It is in a position buried between the flow path members 5. Therefore, the space on the tip side of the top surface portion 30 of the flame hole member 3 is partitioned by the walls of the two air flow path members 5. In the present embodiment, the space surrounded by the top surface portion 30 of the flame hole member 3 and the two air flow path members 5 functions as the first combustion portion 46.

Next, the function of the combustion apparatus 1 will be described.
Many combustion apparatuses 1 are arranged in a box (not shown) and are blown by a blower 41 from the lower side of the drawing. Further, the fuel gas is introduced from the gas inlet 43 of the premixing member 2 by the nozzle 42.
First, the flow of air will be described. The flow of the blast is shown by a solid line in the drawing.
The blown air generated by the blower 41 is rectified by the opening 45 of the rectifying plate 44 and enters the inside of the combustion device 1 from the base end (lower side of the drawing) of the combustion device 1.
There are three routes of blowing into the combustion device 1. That is, the first route is a route that passes through the air flow path member 5, and the air flow enters the air flow path member 5 from the air introduction opening 15 provided at the base end portion of the air flow path member 5, and the internal air flow path 13 flows directly upward toward the tip side. And most of the air is discharged to the outside through the tip openings 20 and 21.

A part of the air flowing through the air flow path member 5 is also discharged from the air discharge opening 23 for the combustion section and the air discharge opening (upstream air discharge opening) 48.
The air discharged from the air discharge opening 23 for the combustion part is discharged obliquely forward from the inclined surface 22 of the step part with respect to the axis of the combustion apparatus 1.
Further, the air discharged from the air discharge opening (upstream air discharge opening) 48 flows through the gap 40 between the air flow path member 5 and the intermediate member 6 and reaches the side surface portion of the flame hole member 3.

The second route is a route that flows through the intermediate member 6. That is, the intermediate member 6 is configured such that the opening row portion 10 of the premixing member 2 is sandwiched between the side wall portions 31 and 32 of the flame hole member 3, but between the opening row portion 10 and the flame hole member 3. There is a gap, and a part of this gap is open to the lower side of the intermediate member 6.
Therefore, air enters between the premixing member 2 and the side wall portions 31 and 32 of the flame hole member 3 from the opening 28.
This air flows through the gap between the side wall portions 31 and 32 and the opening row portion 10 and enters the mixing space 39. Subsequently, it flows into the space 47 between the opening row portion 10 and the top surface portion 30 portion of the flame hole member 3. That is, the above-described air flows through the flame hole upstream flow path 49. Then, it is discharged from the slit as the flame hole 33 to the first combustion section 46. Part of the air that has entered the space 47 enters the gap 29 between the main body member 25 and the side wall portions 31 and 32 through the opening 35 provided in the side wall portion of the main body member 25, and the second side through the side-side flame hole 27. It is discharged to one combustion part 46.

  Next, the third route of air will be described. The third route is a route for primary air, and is introduced from the gas introduction port 43 of the premixing member 2 together with the fuel gas. Since the third route is the same as the route through which the fuel gas flows, the following description will be given as the flow of the fuel gas. The flow of fuel gas is illustrated by solid arrows.

Fuel gas is introduced from the gas inlet 43 of the premixing member 2 together with the primary air. The fuel gas is mixed with air in the mixing unit 7 or the like and flows into the opening row unit 10. In the opening row portion 10, since a large number of openings 8 are arranged in a straight line, the fuel gas that has entered the opening row portion 10 is evenly discharged from each opening 8. The fuel gas discharged from the opening 8 of the opening row portion 10 enters the mixing space 39 formed between the side wall portions 31 and 32 of the flame hole member 3 and the opening 8 of the opening row portion 10 and flows upstream of the flame hole. It is mixed with the air flowing through the passage (including the mixing space 39) 49.
Here, the air flowing through the flame hole upstream flow path (including the mixing space 39) 49 flows in the height direction (from the bottom to the top) of the combustion apparatus 1 whereas it is discharged from the openings 8 of the opening row portion 10. The injected fuel gas flows in a direction perpendicular to the air flow. Therefore, the fuel gas discharged from the opening 8 of the opening row portion 10 collides violently with the air even at the portion of the mixing space 39, and the mixing with the air is promoted. Further, since the mixing space 39 communicates over the entire longitudinal direction of the opening row portion 10, the pressure is also smoothed.

  The fuel gas passes through the mixing space 39 and flows into the space 47, and the mixing of the fuel gas and air is also promoted during this period. After that, the flow is the same as the flow of the flame hole upstream flow path 49 described above, and enters the space 47 between the opening row portion 10 and the top surface portion 30 portion of the flame hole member 3, and many portions are the flame holes 33. It is discharged from the slit to the first combustion section 46. Part of the air that has entered the space 47 enters the gap 29 between the flame-holding wall 26 and the side walls 31, 32 from the openings 35 provided in the side walls 31, 32 of the main body member 25, It is discharged from the flame hole 27 to the first combustion part 46.

The fuel gas discharged from the flame hole 33 is mixed with air in the premixing member 2 and further mixed with air in the mixing space 39, so that the fuel gas is homogeneous and the speed at which the fuel gas is discharged from the flame hole 33. Is even.
However, although the fuel gas discharged from the flame hole 33 is mixed with air, the amount of air is less than the theoretical amount of air. The fuel gas released from the flame hole 33 is in an air-deficient state and cannot be burned completely.

When the fuel gas is ignited, the fuel gas generates a primary flame in the first combustion unit 46, and primary combustion is performed. However, since the fuel gas is in an air-deficient state as described above, it cannot be burned completely, and many unburned components are generated.
Unburned components are discharged to the outside from the opening of the first combustion section 46. Here, air is supplied to the outside of the first combustion unit 46 from the tip of the air flow path member 5. For this reason, the unburned components are supplied with oxygen and undergo secondary combustion. That is, the area outside the first combustion part 46 functions as a second combustion part, and a secondary flame is generated.

In this embodiment, air is supplied to the base end portion of the primary flame described above, and flame holding occurs at the base end portion of the primary flame.
In the present embodiment, the fuel gas is not only released from the flame hole 33 which is the “opening at the center”, but also released from the side-side flame hole 27 to the first combustion part 46. However, the flow rate of the fuel gas discharged from the side-side flame hole 27 is slower than that of the fuel gas discharged from the flame hole 33 which is the “center opening”. That is, the fuel gas enters the gap 29 between the flame holding wall 26 and the side wall portions 31 and 32 through the opening 35 provided in the side wall portions 31 and 32 of the main body member 25, and the first combustion is performed from the side-side flame hole 27. Released to the part 46. Therefore, the amount of the fuel gas entering the gap 29 is limited, and the amount released from the side-side flame hole 27 is small. On the other hand, since the side-side flame hole 27 has a large opening area, the fuel gas discharged from the side-side flame hole 27 has a slow flow rate.

Further, as described above, a part of the air passing through the air flow path member 5 enters the gap 40 between the air flow path member 5 and the intermediate member 6 from the air discharge opening (upstream air discharge opening) 48. It is discharged and reaches the side surface portion of the flame hole member 3 through the gap 40. Therefore, the side surface portion of the flame hole member 3 is rich in oxygen compared to other parts, and the fuel gas discharged from the side surface side flame hole 27 is supplied with air and burns relatively stably.
As described above, in combination with the low flow rate of the fuel gas, stable flame holding occurs in the vicinity of the side-side flame hole 27. Therefore, the base end portion of the primary flame is held by a small flame generated in the vicinity of the side-side flame hole 27.

In particular, in the present embodiment, a step portion (head portion) 120 is provided between the top surface portion 30 which is a main flame hole forming portion of the flame hole member 3 and the side wall portions 31 and 32, and the main flame hole 121 and the side wall portion are provided. There is a distance L between 31 and 32 in the thickness direction of the flame hole member 3. Therefore, there is a distance L between the main flame hole 121 and the side-side flame hole 27 in the thickness direction of the flame hole member 3.
Further, if the height of the stepped portion (head portion) 120 is H, there is an opening of H or more in the height direction (fuel gas flow direction) between the main flame hole 121 and the side-side flame hole 27. .
Therefore, the flame holding 123 is generated at a position slightly away from the main flame 125 of the first flame. As shown in FIG. 2, the flame holder 123 flows to the step portion 120 and reaches the base of the main flame 125 of the first flame, but the amount of coalescence with the main flame 125 of the first flame is small, and the main flame 125 of the first flame 125 Do not extend the length excessively.

In the present embodiment, the secondary flame is stabilized by the air discharged from the combustion part air discharge opening 23. That is, in this embodiment, there is an inclined surface 22 on the front and back surfaces 11 and 12 of the air flow path member 5 and corresponding to the base end portion of the first combustion portion. Since 23 is provided, air is supplied from the base end portion of the first combustion section in an oblique direction with respect to the air traveling direction. Therefore, the supplied air is supplied into the first combustion unit 46 without disturbing the flow of the primary flame and unburned gas. As a result, part of the unburned gas in the first combustion section 46 starts to burn, and a secondary flame is generated in part. And since this secondary flame is connected with the external secondary flame, the secondary flame generated outside is also stable.
Further, in this embodiment, the air discharge opening 23 for the combustion part opens in an oblique direction and does not hinder the flow of the primary flame and unburned gas as described above, so that the secondary flame is separated from the air flow path member 5. The air flow path member 5 is not excessively heated.
Therefore, the combustion apparatus of the present embodiment is practical because both the primary flame and the secondary flame are stable.

In the embodiment described above, the step portion 120 is provided on the main body member 25 of the flame hole member 3, but an inclined surface may be provided instead of the step portion 120. Further, in the above-described embodiment, the height of the projecting end portion 126 of the flame holding wall 26 is upstream of the boundary 122 between the stepped portion (head portion) 120 and the side wall portions 31 and 32 with respect to the flow direction of the fuel gas. However, even if the flame holding wall 26 is a little higher, a certain effect can be expected.
That is, it is desirable that the position of the projecting end portion 126 of the flame-holding wall 26 is lower than the step portion (head portion) 120, but a certain degree of effect can be expected even at a position corresponding to the step portion (head portion) 120. . In other words, if the position of the projecting end portion 126 of the flame-holding wall 26 is on the upstream side of the boundary between the drop portion 120 and the top surface portion 30, an effect of suppressing the primary flame from extending can be expected.

3, 4, and 5 show an example in which the stepped portion is replaced with an inclined surface, and an example in which the position of the protruding end portion 126 of the flame holding wall 26 is designed to be higher.
That is, in the embodiment shown in FIG. 3, a step portion 120 is provided on the main body member 25 of the flame hole member 3, and the position of the projecting end portion 126 of the flame holding wall 26 is set to the lower surface 127 of the step portion 120 and It was set between the end portions of the surface portion 30. In the embodiment shown in FIG. 3, the position of the projecting end 126 of the flame holding wall 26 in the fuel gas flow direction is upstream of the boundary 128 between the stepped portion (head portion) 120 and the top surface portion 30.
In the embodiment shown in FIG. 4, the main body member 25 of the flame hole member 3 is provided with the inclined portion 130, and the position of the projecting end portion 126 of the flame holding wall 26 is set lower than the lower end 131 of the inclined portion 130.
In the embodiment shown in FIG. 5, an inclined portion 130 is provided in the main body member 25 of the flame hole member 3, and the position of the protruding end portion 126 of the flame holding wall 26 is set between the upper end 132 and the upper end 131 of the inclined portion 130. did.

  On the other hand, if the protrusion 126 of the flame holding wall 26 is at an excessively low position, the main flame holding effect by flame holding is impaired. Therefore, the height of the protruding portion 126 of the flame-holding wall 26 is preferably about 0 to 3 mm lower than the height of the lower surface 127 of the stepped portion (head portion) 120, and the difference between users exceeds 3 mm. Not desirable.

Next, a more practical configuration example of the present invention will be described with reference to FIG. The embodiments described below are practically designed to implement the present invention and are the most recommended configurations.
The basic configuration and basic functions of the combustion apparatus shown in the drawings after FIG. 6 are the same as those of the above-described embodiment, but practical devices are applied to the details. The members having the same functions as those of the previous embodiment are denoted by the same reference numerals, and the description of the overlapping functions will be simplified.

  The combustion apparatus 1 shown in FIG. 6 is used in parallel with a case 54 as shown in FIGS. The combustion apparatus 1 of the present embodiment also has a premixing member 2, a flame hole member 3, and an air flow path member 5. The premixing member 2 and the flame hole member 3 are fitted together to constitute one intermediate member 6, and the intermediate member 6 is sandwiched between the two air flow path members 5.

  The shape of the premixing member 2 is as shown in FIGS. The premixing member 2 is formed by pressing a single steel plate to form a developed figure having irregularities on the surface, bending it, and then joining the periphery by spot welding. Spot welding is performed at the surrounding flange portion 51.

The shape of the premixing member 2 after assembling is such that a front plate 52 as shown in FIGS. 13 and 14 and a symmetrical back plate 53 are superimposed on each other. The external appearance of the premixing member 2 has a sharp shape, has a flat top 50, and is closed so that gas does not leak out.
A series of gas passages are formed between the front plate 52 and the back plate 53 inside. That is, in the part where the unevenness of the front plate 52 and the back plate 53 coincides, the metal plates are arranged in a gap, and a gas flow path is formed by this gap.

In the premixing member 2 employed in the present embodiment, the gas flow path is largely divided into upper and lower parts as shown in FIG. Specifically, the gas flow path is roughly composed of a mixing flow path 19 and an opening row portion 10.
As shown in FIG. 14, the mixing channel 19 is on the lower side of the premixing member 2 and is a channel from the inlet of the gas channel to the opening row portion 10. If it demonstrates from the inlet_port | entrance of a gas flow path, the gas inlet 43 will open in the lower corner of the combustion apparatus 1 like FIG. In the vicinity of the gas introduction port 43, an introduction portion 102 having a substantially constant inner diameter shape is formed. The leading end of the introduction portion 102 is a venturi portion 103 whose inner diameter is tapered. The venturi unit 103 has an action of increasing the flow velocity and sucking air and fuel gas. At the end of the venturi portion 103, there is a narrowed throttle portion 55 with the smallest cross-sectional area, and further on the downstream side there is a diameter-expanded portion 56 whose cross-sectional area gradually increases. After that, the uniform cross section 57 has a uniform cross section. The flow path is linear from the gas introduction port 43 to the uniform cross section 57 through the throttle portion 55 and the enlarged diameter portion 56.
The end of the uniform cross section 57 is connected to the opening row portion 10 with the flow path bent vertically.
In the present embodiment, there is no portion that becomes a stop immediately before the opening row portion 10.

The opening row | line | column part 10 is located in the upper end part of the premixing member 2, and is extended over the whole longitudinal direction like FIG. The cross-sectional area of the opening row 10, in other words, the gap between the front plate 52 and the back plate 53 at that portion is large as shown in FIGS.
The cross-sectional shape of the opening row portion 10 is a two-stage shape as shown in FIGS. 15 and 16, and the top side is a narrow area portion 58, and the cross-sectional area is slightly narrow.
That is, the cross-sectional shape of the opening row portion 10 will be described. The top portion 50 is flat, and the upper side vertical wall 81 is perpendicular to both sides of the top portion 50. The end of the vertical wall 81 is connected to the inclined wall and extends slightly outward. Further, the end of the inclined wall is a lower side vertical wall 82.

A large number of openings 8 are provided on both the front plate 52 and the back plate 53 in the narrow area 58 described above, which is the outer surface of the opening row portion 10. The openings 8 are provided in a line along a straight line with a certain interval.
In the present embodiment, the opening 8 is provided only on the front side and the back side of the opening row portion 10, and the top portion 50 has no opening.

Next, the air flow path member 5 will be described with reference to FIGS. The air flow path member 5 is also formed by pressing a single steel plate to form a developed figure having irregularities on the surface, bending it, and then joining it by spot welding. In the air flow path member 5, the front and back surfaces 11 and 12 are joined with a slight gap as shown in FIG. 13, and a space that becomes the air flow path 13 is provided inside.
There is an acute bent portion at the tip of the air flow path member 5, and the apex portion 9 is constituted by the bent portion. The top portion 9 extends in a ridgeline shape.
As shown in FIG. 17, the air flow path member 5 is provided with flange portions 83 on two sides in contact with the bent portion, and the flange portions 83 are spot-welded.
On the base end side of the air flow path member 5, the space between the front and back plates 11 and 12 is opened as shown in FIG. 13, and an air introduction opening 15 is formed.

The external shape of the air flow path member 5 is a thin wall shape as shown in FIG. The air flow path member 5 is roughly divided into three regions with respect to the height direction on the basis of the vertically placed state as shown in FIG.
That is, the introduction portion 60 extends from the base end portion to a height of about 1/3. Furthermore, the region of about ３ in the height direction is the intermediate portion 61. The approximately 1/3 region on the front end side is the first combustion portion constituting portion 62.

The air flow path member 5 constitutes a flow path from the air introduction opening 15 toward the front end side, but the cross-sectional area of the flow path becomes narrower toward the front end side.
That is, the cross-sectional area of the portion (introduction portion 60) from the air introduction opening 15 to about 1/3 of the total height is substantially constant as shown in FIG. In other words, the introduction part 60 has the front and back surfaces 11 and 12 parallel to each other as shown in the cross-sectional view of FIG.

The intermediate part 61 is generally tapered.
That is, the intermediate portion 61 has a tapered shape in which the lower portion is wide as shown in the drawing and the interval is narrowed toward the upper portion. However, a bulging portion 84 is provided at a boundary portion between the distal end side end portion of the taper and the first combustion portion constituting portion 62. As for the outer wall part which comprises the bulging part 84, the front and back part is parallel.

Although the cross-sectional area of the first combusting part constituting part 62 is substantially constant (excluding the top part 9), the cross-sectional area per unit length during this period is about 1/3 of that of the introducing part 60.
There is a step portion formed of the inclined surface 22 between the first combustion portion constituting portion 62 and the intermediate portion 61.

The air flow path member 5 is provided with air discharge openings in three regions.
The positions where the air discharge openings are provided are roughly divided into a front end portion, a position facing the first combustion portion, and a position facing the intermediate member 6.

That is, the front end portions of the front and back surfaces 11 and 12 of the air flow path member 5 are bent in a mountain shape, and inclined surfaces 16 and 17 are formed on the front surface side and the back surface side. The inclined surfaces 16 and 17 are provided with a circular tip opening 20 as shown in FIG. In addition, a circular tip opening 21 is also provided at the most distal portion (ridge line portion).
Further, in the present embodiment, slit-shaped tip openings 63 and 64 are provided on the top and the inclined surfaces 16 and 17. There are two types of slit lengths: the smaller slit-shaped tip opening 63 is a slit that connects all the inclined surfaces 16, 17 and the top 9. The larger slit (front end opening) 64 is longer and extends from the portion where the front and back surfaces 11 and 12 are parallel to the top portion 9.

The large slits (tip opening) 64 have a larger number than the small slits (tip opening) 63, and the large slits 64 are continuously provided in two or three rows, and then the small slits 63 are provided. Subsequently, two or three rows of large slits 64 are continuously provided, and these are continuous over the entire length direction of the air flow path member 5.
The circular tip openings 20 and 21 are provided between the slits (tip openings) 63 and 64.

  The front end openings 20 and 21 are provided to supply secondary air to the secondary flame, as in the previous embodiment.

  An air discharge opening 23 for the combustion part is provided on the inclined surface 22 between the first combustion part constituting part 62 and the intermediate part 61 described above. The air discharge opening 23 for the combustion part supplies secondary air to the primary flame of the first combustion part 46 and burns a part of the primary flame to generate a secondary flame in part.

  Further, an air discharge opening (upstream air discharge opening) 48 is also provided in the vicinity of the boundary between the introduction portion 60 and the intermediate portion 61. The air discharge opening (upstream air discharge opening) 48 supplies air to the side surface portion of the flame hole member 3 to stabilize flame holding.

The front and back surfaces 11 and 12 of the air flow path member 5 are provided with uneven shapes in each part for the purpose of providing a gap between them or for providing a gap between other members.
To explain sequentially, a plurality of concave grooves 70 and 71 extending in the height direction are provided on the wall surface constituting the first combustion portion constituting portion 62 on the front end side. The concave grooves 70 and 71 are both concave when viewed from the surface side, and extend in the height direction. The concave groove 70 is shorter than the concave groove 71. The concave grooves 70 and 71 are both arranged in parallel. The concave grooves 70 and 71 are provided mainly for reinforcing the plate.
In this embodiment, a plurality of short grooves 70 are provided, followed by a long groove 71, and a plurality of short grooves 70 are provided, and the grooves 70 are formed over the entire width of the air flow path member 5. , 71 are arranged.

Further, the distance between the long grooves 71 is wider than the distance between the other grooves.
A streamlined recess 72 as shown in FIGS. 17 and 18 is provided between the long recesses 71 and in the vicinity of the base end of the recess 71. The concave deformation portion 72 is also a concave shape when viewed from the front side. Specifically, the shape of the concave change portion 72 is such that a large circle and a small circle are arranged apart from each other and connected by a common tangent line, and the large circle side is located upstream of the air flow path. However, the small circle side is located downstream of the air flow path. A line connecting the centers of the two circles is parallel to the air flow direction. A common tangent line connecting two circles has an inclination of 30 ° or less with respect to a line connecting the centers of the circles.

  The middle portion 61 of the air flow path member 5 is provided with six ridges 73 as shown in FIG. The direction of the ridges 73 is parallel to the air flow direction. As will be described later, the ridge 73 is in contact with the outer surface of the intermediate member 6 to provide a gap therebetween, and the position of the protrusion (ridgeline) of the ridge 73 (from the center line of the air flow path member 5). (Distance) is the same in any part. That is, as described above, in the intermediate portion 61, the cross-sectional shape of the flow path is tapered, but the height of the ridge 73 (the size of the bulge) changes to a reverse tapered shape, and the positions of the protruding end portions are aligned. .

  A plurality of concave grooves 75 are also provided in parallel in the introduction portion 60 of the air flow path member 5. Each of the concave grooves 75 extends from the proximal end side to the distal end side of the air flow path member 5. The concave groove 75 has a concave shape when viewed from the surface side.

A concave groove 77 extending in the lateral direction (perpendicular to the air flow) is provided in the vicinity of the introduction portion 60 of the air flow path member 5.
The concave groove 77 is provided mainly for positioning.

  Further, when the eyes are moved to the side surface portion of the air flow path member 5, a substantially triangular protrusion 80 is provided at the center portion of both side surfaces.

Next, the flame hole member 3 will be described. The flame hole member 3 has a flame holding wall 26 welded to the side surface of the main body member 25 as shown in FIGS.
The main body member 25 of the flame hole member 3 is also formed by pressing a single steel plate to form a developed figure having irregularities on the surface, bending it, and spot welding. As shown in FIG. 19, the main body member 25 also has flanges 85 on two sides connected to the top surface portion 30, joined by the flange 85, and the surface facing the top surface portion 30 is released.

  The main body member 25 of the flame hole member 3 has a top surface portion 30 that functions as a flame hole and a step portion (head portion) 120 as shown in FIGS. And it has the two side wall parts 31 and 32 bent about 90 degrees from the step part (fall part) 120. As shown in FIG.

The top surface portion 30 of the flame hole member 3 is elongated and is elongated. The top surface portion 30 is flat in this embodiment.
In this embodiment, the step (head part) 120 is vertical. That is, the stepped portion (head portion) 120 includes a vertical wall 131 bent perpendicular to the top surface portion 30 and a lower surface 127 bent perpendicular to the vertical wall 131.
The flame hole member 3 is formed by bending a steel plate as described above, but the steel plate is folded into the top surface portion 30. Therefore, as shown in the drawing, the folded portion hangs down as a vertical wall 88 in the internal cavity.

  The top surface portion 30 of the main body member 25 is provided with a slit-like opening that becomes a flame hole (center side opening) 33. The slit (flame hole 33) extends in the width direction of the top surface portion 30, and both ends thereof reach the vertical wall 131 of the stepped portion (head portion) 120.

  A plurality of slit-like openings are arranged in parallel and are provided in the entire longitudinal direction of the top surface portion 30. Then, as shown in FIG. 19, a flame hole group 89 is constituted by a set of a plurality of slit-like openings, and the flame hole group 89 is arranged on the top surface 30 at regular intervals.

Paying attention to the cross-sectional shape of the main body member 25, the main body member 25 has two narrowed portions 78 and 79 as shown in FIG. In other words, there are two bulging portions 90 and 91 except for the base end portion.
In other words, there are a tip-side bulged portion 90 including the portion of the top surface 30 and an intermediate bulged portion 91 provided in the intermediate portion. A front end side narrowed portion 78 is provided between the intermediate bulging portion 91 and the front end side bulging portion 90. Further, a proximal end side throttle portion 79 is provided on the proximal end side of the intermediate bulging portion 91.

Of the bulging portions 90 and 91 and the narrowed portions 78 and 79 described above, the tip-side bulging portion 90 and the intermediate bulging portion 90 are both provided over the entire width of the flame hole member 3.
Further, openings 35 are provided in a row on the side surface of the distal side bulging portion 91 as shown in FIG. The opening 35 is a small hole.
The proximal end side narrowed portion 79 is provided with a plurality of ridges 92 as shown in FIG. The ridge 92 protrudes outward as seen from the surface side, and a groove 93 is formed inside as shown in FIG. The ridge 92 extends in the height direction of the flame hole member 3. The ridge 92 extends in parallel with the width direction of the flame hole member 3.

The open end sides of the side wall portions 31 and 32 are folded back approximately 90 ° twice as shown in FIGS. 11, 13, 21, and 22, and a fitting concave groove 38 is formed on the outside. The bottom wall 36 of the fitting groove 38 is perpendicular to the side walls 31, 32, and the outer wall 37 of the fitting groove 38 is parallel to the side walls 31, 32.
The outer wall 37 constituting the fitting groove 38 has a substantially trapezoidal front shape. That is, the sides on both sides of the outer wall 37 are inclined as shown in the enlarged view of FIG. 20, and the tip side is tapered in a tapered shape. Further, as shown in FIGS. 21 and 22, projections 95 are provided on the side wall portions 31 and 32 in the fitting groove 38. The positions of the protrusions 95 are at both ends of the fitting concave groove 38, and one protrusion 95 is provided at each end.

  The flame holding wall 26 is fixed to the upper end portions of the side wall portions 31 and 32 of the main body member 25. The flame-holding wall 26 has a long plate shape as shown in FIG. 19 and covers the tip-side bulged portion 90 of the main body member 25 over the entire area. There is a gap 29 between the side wall portions 31, 32 of the main body member 25 and the flame holding wall 26. The gap 29 is open on the upper side of the drawing. This opening functions as a side-side flame hole 27. A small protrusion 97 is formed on the inner surface of the flame-holding wall 26 as shown in FIG. 13, and the protrusion 97 abuts the main body member 25 to regulate the interval between the side-side flame holes 27.

  The height of the projecting end portion 126 of the flame holding wall 26 is lower than the lower surface 127 of the stepped portion (head portion) 120 as shown in FIGS. That is, the projecting end portion 126 of the flame holding wall 26 is on the upstream side of the boundary 122 between the step portion (head portion) 120 and the side wall portions 31 and 32.

  As described above, the distal-side bulging portion 90 has the openings 35 (FIG. 19) in a line, and the openings 35 communicate the inner surface of the main body member 25 with the gap 29.

  Both end portions of the main body member 25 are overlapped with the side wall portions 31 and 32 to form a flange 85 and are joined by spot welding, but the side wall portion extends from the proximal end side to the vicinity of the intermediate bulge portion. There is a slit 98 between 31 and 32.

Next, the relationship between the members will be described with reference to FIGS.
Also in the combustion apparatus of the present embodiment, the premixing member 2 and the flame hole member 3 are fitted together to constitute the intermediate member 6.
Although the flame hole member 3 (intermediate member 6) is located between the two air flow path members 5 as described above, the top surface 30 of the flame hole member 3 is more than the upper end of the air flow path member 5. It is on the lower side of the drawing and is in a position buried between the air flow path members 5. Therefore, the space on the tip side of the top surface 30 of the flame hole member 3 is partitioned by the walls of the two air flow path members 5. In the present embodiment, the space surrounded by the top surface 30 of the flame hole member 3 and the two air flow path members 5 functions as the first combustion portion 46.

The intermediate member 6 is obtained by mounting the premixing member 2 on the flame hole member 3, and the top 50 side of the premixing member 2 is inserted into a hollow portion of the flame hole member 3. At this time, the flange portions 51 at both ends of the premixing member 2 are fitted into the slits 98 formed at both ends of the flame hole member 3. Then, the protruding end of the premixing member 2 and the back end of the slit 98 come into contact with each other and positioning in the insertion direction is performed.
Further, the vertical wall 82 provided on the lower side of the opening row portion 10 of the premixing member 2 is brought into contact with the inner wall of the base end side restricting portion 79 of the flame hole member 3 so as to be positioned in the thickness direction.
The narrow area portion 58 of the opening row portion 10 of the premixing member 2 is the position of the intermediate bulging portion 91 of the flame hole member 3.

  When attention is paid to the gap between the opening row portion 10 of the premixing member 2 and the flame hole member 3, the narrowness of the opening row portion 10 is narrowed to the intermediate bulging portion 91 of the side wall portions 31 and 32 of the flame hole member 3 as described above. There is an area 58. That is, the portion of the intermediate bulging portion 91 corresponds to the row portion of the openings 8 of the opening row portion 10. Therefore, the outer side of the opening 8 of the opening row part 10 is separated from the side wall parts 31 and 32, and there is a wider space (mixing space) 39 than the other on the outer side of the opening 8. The mixing space 39 communicates over a portion corresponding to all the openings 8.

  On the other hand, as described above, the lower side of the opening row portion 10 of the premixing member 2 is in contact with the inner wall of the base end side throttle portion 79 of the flame hole member 3. Therefore, the outer wall of the opening row portion 10 and the inner wall of the flame hole member 3 are in contact with each other at almost all positions in the width direction, and there is no gap. However, the base end side restricting portion 79 is provided with a plurality of protruding ridges 92 as described above, and the inner surface side of the protruding ridges 92 is a concave groove 93 (FIG. 11). Therefore, in the portion of the ridge 92, the outer wall of the opening row portion 10 and the inner wall of the flame hole member 3 are separated. Further, since the ridge 92 extends in the height direction of the flame hole member 3, the mixed space 39 communicates with the base end side of the flame hole member 3.

  Here, paying attention to the positional relationship between the position of the ridge 92 and the opening 8 provided in the opening row portion 10 of the premixing member 2, the opening 8 is at a position directly above the ridge 92 as shown in FIG. That is, when the ridge 92 is extended, it intersects with the position of the opening 8. In the present embodiment, as shown in FIG. 23, the protrusions 92 and the openings 8 correspond one to one. However, as shown in FIG. 24, the openings 8 do not necessarily correspond one-to-one, such that the number of the openings 8 is larger, or the number of the protrusions 92 is larger.

There is a gap between the base end portion of the flame hole member 3 and the premixing member 2. Therefore, the mixing space 39 described above communicates with the outside through the protrusions 92 (concave grooves 93) and the gaps at the base end portions.
On the other hand, paying attention to the further front end side of the mixing space 39, a relatively large space 47 between the side wall portions 31 and 32 and between the top portion 50 of the opening row portion 10 and the top surface portion 30 portion of the flame hole member 3. There is. In the present embodiment, the flame hole upstream flow path 49 is formed by the mixing space 39 and the space 47 downstream of the opening row portion 10.

Air flow path members 5 are mounted on both sides of the intermediate member 6 as shown in FIGS. The air flow path member 5 is fixed to the intermediate member 6 by fitting the fitting concave groove 38 of the flame hole member 3 into the air introduction opening 15 on the proximal end side. That is, the outer wall 37 of the fitting groove 38 is inserted into the air introduction opening 15, and the projecting end of the air flow path member 5 is inserted into the fitting groove 38 and brought into contact with the bottom wall 36 of the fitting groove 38.
As described above, the outer wall 37 of the concave groove for fitting 38 is trapezoidal when viewed from the front, and the sides on both sides are tapered. Therefore, when the air flow path member 5 is mounted, The inner wall follows the taper of the outer wall 37 of the fitting concave groove 38, and positioning in the width direction is performed.
When the air flow path member 5 is placed in a proper position with respect to the flame hole member 3, as shown in FIG. 22, the fitting concave groove 38 is formed on the outer upper end of the concave groove 77 provided in the vicinity of the opening of the air flow path member 5. The protrusion 95 provided inside engages and a feeling of moderation is obtained.
Further, when the air flow path member 5 is mounted at a proper position, the air discharge opening 23 for the combustion part is positioned between the flame hole group 89 and the flame hole group 89 of the flame hole member 3 in the width direction. become.
At the upstream end (the lower end in the drawing) of the combustion device 1, the gap 40 between the air flow path member 5 and the intermediate member 6 is sealed by the bottom wall 36 of the fitting groove 38. Therefore, the gap 40 between the air flow path member 5 and the intermediate member 6 does not directly communicate with the outside world on the base end side.

When attention is paid to the gap 40 between the air flow path member 5 and the intermediate member 6 (flame hole member 3), the side surface side of the upstream air discharge opening 48 of the air flow path member 5 as shown in FIGS. The leading end side throttle portion 78 of the flame hole member 3 is located. Since the front end side throttle portion 78 is a portion where the surface of the flame hole member 3 is recessed, there is a gap between the air flow path member 5 and the flame hole member 3 in the vicinity of the upstream air discharge opening 48.
Further, this gap communicates with the first combustion portion 46. That is, the air flow path is tapered on the front end side of the upstream side air discharge opening 48 of the air flow path member 5, and the outer wall of the air flow path member 5 is located inside the air flow path as it goes downstream. A gap is formed between the flame hole member 3 and the flame hole member 3. The outer wall of the air flow path member 5 and the flame hole member 3 are partially in contact with each other by a ridge 73 provided on the air flow path member 5.

Next, the function of the combustion apparatus 1 will be described.
A large number of combustion apparatuses 1 are arranged in a case 54 as shown in FIG. 7, and are blown by a blower 41 from the lower side of the drawing as shown in FIG. Further, the fuel gas is introduced from the gas introduction port 43 of the premixing member 2 by a nozzle (not shown).
The flow of the blast is substantially the same as in the above-described embodiment, and the blast generated by the blower 41 is rectified by the opening of the rectifying plate 44 (FIG. 8), and from the base end (lower side of the drawing) of the combustion device 1. It enters the inside of the combustion apparatus 1.
The route of the air entering into the combustion apparatus 1 is the same as that in the previous embodiment, and there are three routes. That is, the first route is a route passing through the air flow path member 5 as shown in FIG. 11, and the air flow enters the air flow path member 5 from the air introduction opening 15 provided at the base end portion of the air flow path member 5. , Flows through the internal air flow path 13 toward the tip side. And most of the air is discharged to the outside through the tip openings 20 and 21.

Here, in this embodiment, as shown in FIG. 25, the tip shape of the air flow path member 5 is an acute angle, and the tip opening 63, 64 of the tip opening is formed on the inclined surfaces 16, 17 and the top. Since the slits are provided across the air, it is difficult for air to stay at the tip portion or to cause turbulence.
For example, as shown in FIG. 26, if the tip shape of the air flow path member 5 is circular, the air introduced from the air introduction opening 15 collides with the arc surface that is the ceiling surface, and moves toward the base end side along the arc surface. Wrap around. Then, the sneak-in air collides with the newly supplied air flow as shown by an arrow, and inhibits the discharge of the newly supplied air to distort the discharge direction. In this way, when the tip shape of the air flow path member 5 is circular, the direction of the air flow becomes unstable due to the generation of turbulence and vortices. For this reason, a problem that the secondary flame fluctuates occurs. Further, according to the experiments by the present inventors, there is a problem that the noise is high.

  On the other hand, in the present embodiment, as shown in FIG. 25, since the tip portion has an acute angle, there are few portions where the supplied air collides, and the air does not wrap around. Further, since the slit-shaped opening is provided on the inclined surface, most of the air that collides with the inclined surface is discharged to the outside from the slit-shaped opening. For this reason, the air discharge direction is stabilized, and the fluctuation of the secondary flame is reduced. Noise is also reduced. However, the present invention does not limit the tip shape of the air flow path member, and the tip shape as shown in FIG. 26 may be circular.

Returning to the description of the embodiment, in the combustion apparatus 1 of this embodiment, a part of the air flowing through the air flow path member 5 flows from the air discharge opening 23 for the combustion section and the air discharge opening (upstream air discharge opening) 48. Are also released.
The air discharged from the air discharge opening 23 for the combustion part is directed from the inclined surface 22 of the step part between the flame hole group 89 and the flame hole group 89 of the flame hole member 3 with respect to the axis of the combustion device 1. Is released diagonally forward.
Further, the air discharged from the air discharge opening (upstream air discharge opening) 48 flows through the gap 40 between the air flow path member 5 and the intermediate member 6 and reaches the side surface portion of the flame hole member 3. Specifically, the air discharged from the air discharge opening (upstream air discharge opening) 48 is discharged into a gap formed by the front end side throttle portion 78 of the flame hole member 3. This air flows through a gap formed by the tapered wall surface of the air flow path member 5 and is released to the side surface portion of the flame hole member 3.

The second route is a route that flows through the intermediate member 6, and air enters between the premixing member 2 and the side wall portions 31 and 32 of the flame hole member 3 from the opening 28.
This air passes through a concave groove 93 formed on the inner surface of the flame hole member 3 (the back side of the ridge 92) and enters the mixing space 39. Then, the space 47 between the opening row portion 10 and the top surface portion 30 of the flame hole member 3 enters. That is, the above-described air flows through the flame hole upstream flow path 49. Then, the gas is discharged from the slit serving as the flame hole (center side opening) 33 to the first combustion unit 46. Part of the air that has entered the space 47 enters the gap 29 between the main body member 25 and the side wall portions 31 and 32 through the opening 35 provided in the side wall portion of the main body member 25, and the second side through the side-side flame hole 27. It is discharged to one combustion part 46.

  Next, the third route of air will be described. The third route is a route for primary air, and is introduced from the gas introduction port 43 of the premixing member 2 together with the fuel gas. Since the third route is the same as the route through which the fuel gas flows, the following description will be given as the flow of the fuel gas. The flow of fuel gas is illustrated by solid arrows.

The fuel gas is introduced together with the primary air from the gas introduction port 43 of the premixing member 2, mixed with air by the mixing unit 7 and the like, and flows into the opening row unit 10. Here, in the present embodiment, there is no portion that becomes a diaphragm between the uniform section 57 of the mixing portion 7 and the opening row portion 10. Therefore, the fuel gas protrudes into the opening row portion 10 without any portion where the flow velocity is different.
The fuel gas that has entered the opening row 10 is evenly discharged from each opening 8. That is, since the opening row portion 10 has a considerable internal volume, minute vortices generated in the curved path of the premixing member 2 are converged. Further, as described above, there is no portion to be throttled immediately before the opening row portion 10, and the fuel gas introduced into the opening row portion 10 has a small variation in flow velocity in the cross section of the flow path. Therefore, there is little pressure variation in the inside of the opening row | line | column part 10, and fuel gas is discharge | released from each opening 8 equally. The diameter of the opening 8 may be sequentially reduced so that the amount of ejected gas is uniform.

  The fuel gas discharged from the opening 8 of the opening row portion 10 enters the mixing space 39 constituted by the intermediate bulging portion 91 of the flame hole member 3, and passes through the flame hole upstream flow path (including the mixing space 39) 49. Mixed with flowing air.

On the other hand, the air flowing through the mixing space 39 flows upward from the lower side of the drawing and is rectified.
That is, the air flowing into the mixing space 39 is introduced from the opening 28 between the premixing member 2 and the side wall portions 31 and 32 of the flame hole member 3, but before reaching the mixing space 39, the flame hole member Since it passes through the concave groove 93 (the back side of the ridge 92) formed in the inner surface of No. 3, it is a laminar flow.
More specifically, in this embodiment, most of the portion of the base end side throttle portion 79 of the flame hole member 3 is in contact with the outer wall of the premixing member 2. A large number of concave grooves 93 are formed on the inner surface, and there are gaps in the concave groove 93 portions. Each groove 93 communicates with the mixing space 39. Therefore, the air introduced from the opening 28 between the side walls 31 and 32 passes through the plurality of concave grooves 93 and reaches the mixing space 39. And since the ditch | groove 93 is an elongate flow path and is provided in parallel at equal intervals, the introduce | transduced air is rectified by flowing through the some ditch | groove 93. FIG.

The air flowing through the flame hole upstream side flow path (including the mixing space 39) 49 flows in the height direction of the combustion apparatus 1, whereas the fuel gas discharged from the opening 8 of the opening row portion 10 becomes the flow of air. In contrast, it flows vertically. Therefore, the fuel gas discharged from the opening 8 of the opening row portion 10 collides violently with the air even at the portion of the mixing space 39, and the mixing with the air is promoted.
In addition, in the present embodiment, since the opening 8 of the opening row portion 10 is on the extension line of the concave groove 93 (the back side of the ridge 92), the air that has exited the concave groove 93 is more reliably released from the opening 8. Collide with gas.
Further, since the mixing space 39 communicates over the entire longitudinal direction of the opening row portion 10, the pressure is also smoothed.

The fuel gas rises through the mixing space 39 and flows into the space formed by the tip-side bulging portion 90, but the mixing of the fuel gas and air is also promoted during this time. Most of the fuel gas is discharged from the slit that is the flame hole 33 to the first combustion section 46.
The fuel gas discharged from the slit is mixed with air in the premixing member 2 and further mixed with air in the mixing space 39, so that the fuel gas is uniform and the speed when discharged from the slit is also uniform. .
Part of the air and fuel gas that has entered the space 47 enters the gap 29 between the main body member 25 and the side wall portions 31 and 32 from the opening 35 provided in the side wall portion of the main body member 25, and the side-side flame hole 27. To the first combustion section 46.

  When the fuel gas is ignited, the fuel gas generates a primary flame in the first combustion unit 46, and primary combustion is performed. The unburned component is discharged to the outside from the opening of the first combustion unit 46, and air is supplied from the tip of the air flow path member 5 to perform secondary combustion.

In this embodiment, air is supplied to the base end portion of the primary flame described above, and flame holding occurs at the base end portion of the primary flame.
That is, in this embodiment, a part of the fuel gas is discharged from the side-side flame hole 27 to the first combustion unit 46. However, the fuel gas discharged from the side-side flame hole 27 has a slower flow rate than the fuel gas discharged from the slit. That is, the fuel gas enters the gap 29 between the main body member 25 and the side wall portions 31 and 32 from the opening 35 provided in the side wall portion of the main body member 25, and is released from the side-side flame hole 27 to the first combustion portion 46. The Therefore, the amount of the fuel gas entering the gap 29 is limited, and the amount released from the side-side flame hole 27 is small. On the other hand, since the side-side flame hole 27 has a large opening area, the fuel gas discharged from the side-side flame hole 27 has a slow flow rate.

Further, as described above, a part of the air passing through the air flow path member 5 is supplied to the fuel gas discharged from the side-side flame hole 27 and completely burned.
That is, the air discharged from the air discharge opening (upstream air discharge opening) 48 is formed by the tapered wall surface of the air flow path member 5 from the gap formed by the tip side narrowed portion 78 of the flame hole member 3. It flows along the gap and reaches the side surface of the flame hole member 3.

  As described above, in combination with the low flow rate of the fuel gas, stable flame holding occurs in the vicinity of the side-side flame hole 27. Therefore, the base end portion of the primary flame is held by a small flame generated in the vicinity of the side-side flame hole 27.

  Also in this embodiment, there is a step portion (head portion) 120 between the top surface portion 30 which is the main flame hole forming portion of the flame hole member 3 and the side wall portions 31 and 32, and the flame holding 123 is a flame hole. It is generated upstream of the main flame 125 generated from the fuel released from the main flame hole 121 of the member 3. Further, the flame holding 123 is generated not only in the fuel gas flow direction but also in the lateral direction. Thus, the flame holding 123 is generated at a position slightly away from the main flame 125 of the first flame. Therefore, as described above, the flame-holding 123 does not easily merge with the main flame 125 of the first flame, and the length of the main flame 125 of the first flame does not extend excessively.

Also in this embodiment, air is supplied in an oblique direction from the combustion part air discharge opening 23 provided on the inclined surface 22, and a part of the unburned gas in the first combustion part 46 starts to burn, A secondary flame is generated in part. This secondary flame is connected to an external secondary flame.
Further, in the present embodiment, since air is released between the flame hole group 89 and the flame hole group 89 of the flame hole member 3, the air is sufficiently supplied around the flame hole group 89, and the primary flame. The flame can be reliably held.
Also in the present embodiment, the air supplied from the air discharge opening 23 for the combustion section does not interfere with the flow of the primary flame and unburned gas, and the secondary flame is generated at a position away from the air flow path member 5. The air flow path member 5 is not heated excessively.
Therefore, the combustion apparatus of the present embodiment is practical because both the primary flame and the secondary flame are stable.

In the above-described embodiment, the top surface portion 30 of the flame hole member 3 is a flat surface. However, the present invention is not limited to this configuration, and has an inclined surface represented by a roof shape. It may be a thing or it may have an arc surface.
FIG. 27 is an enlarged view of a portion including the vicinity of the top of the flame hole member of the combustion apparatus according to another embodiment of the present invention.
In the combustion device 136 shown in FIG. 27, the top surface portion 137 of the flame hole member 3 has a roof shape, the central ridge line portion 86 is the highest, and both sides thereof are gently inclined portions 87.
Also in the present embodiment, the projecting end portion 126 of the flame holding wall 26 is on the upstream side of the boundary 122 between the stepped portion (falling portion) 120 and the side wall portions 31 and 32.

  In each of the above-described embodiments, a configuration in which an opening for discharging the fuel gas is provided on the side surface as an example of the premixing member. According to this configuration, since the fuel gas is released in a direction perpendicular to the air flow, there are many opportunities for collision between the fuel gas and air, and mixing is promoted.

  In the embodiment shown in FIG. 6 and subsequent figures, a number of uneven shapes are provided on the surface of each member. The uneven shape fulfills the function of improving the rigidity of the plate body in addition to the function of constituting the flow path. Further, the uneven shape that does not constitute the flow path only fulfills the function of improving the rigidity of the plate.

  In each of the above-described embodiments, a series of flow paths is formed by the gaps between the metal plates. That is, one or both plates are provided with a recess, and a gap is formed between the other plate. Here, it is one of the design matters to determine which plate is provided with the groove when forming the flow path, and the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, a part of the second route of the air has a flow path that passes between the inner surface of the flame hole member 3 and the outer peripheral surface of the premixing member. 93 was provided to secure the flow path. However, conversely, the flow path may be configured by providing a groove or the like on the premixing member side.

Next, a modified example of the premix member will be described. The premixing member 2 employed in the above-described embodiment has a mixing channel 19 and an opening row portion 10, and the mixing channel 19 has a throttle portion 55 whose sectional area is temporarily reduced, and further downstream thereof. On the side, there is an enlarged diameter portion 56 whose cross-sectional area gradually increases. . As described above, the premixing member 2 employed in the embodiment described above has only one throttle portion 55, but agitation of fuel gas and air can be promoted by providing a plurality of throttle portions.
28 is a model diagram showing the mixing action of fuel gas and air in the premixing member employed in the embodiment shown in FIG.
In the premixing member employed in the combustion apparatus shown in FIG. 6, the fuel gas 139 injected from the nozzle 42 is introduced from the gas introduction port 43 together with the primary air, and is mixed with air while passing through the mixing channel 19. For example, as shown in FIG. 28, in the introduction portion of the enlarged diameter portion 56, the stirring is insufficient, and the concentration distribution in the cross section C varies considerably. That is, the concentration distribution in the cross section C is as shown by the solid line in FIG. 33, and the gas concentration in the central portion is extremely high.

  As a means for improving this, for example, a measure for disturbing the air flow by placing a baffle plate in the flow path can be considered. However, the measure by the baffle plate has a new problem that noise is generated due to the turbulence of the airflow.

On the other hand, when a plurality of throttle portions and diameter-expanding portions are provided, stirring of the fuel gas and air can be promoted without increasing noise.
FIG. 29 is a perspective view showing a modification of the premixing member employed in the combustion apparatus of the present invention. 30 is a perspective view of the vicinity of the gas inlet of the premixing member of FIG. FIG. 31 is a cross-sectional view showing a change in the flow path in the vicinity of the gas inlet of the premixing member in FIG. 29 and the cross-sectional shape of the flow path at each site. FIG. 32 is a cross-sectional view showing the inside of the premixing member in FIG. 29 in the vicinity of the gas inlet. FIG. 33 is a graph showing the fuel gas concentration distribution in a specific cross section in the premixing member of FIGS. 28 and 29. FIG. 34 is a perspective view of the vicinity of the gas inlet of the premixing member in another embodiment.

The premixing member 140 shown in FIG. 29 has a first enlarged diameter portion 141 and a second restricted portion 142 in addition to the venturi portion 103 and the restricted portion 55 similar to those of the previous embodiment.
That is, in the premixing member 140 shown in FIG. 29, the gas introduction port 43 is opened as in the premixing member 2 of FIG. 14 described above, and the inner diameter shape is substantially constant in the vicinity of the gas introduction port 43. An introduction unit 102 is provided. And the front-end | tip of the introducing | transducing part 102 becomes the venturi part 103 in which the internal diameter contracted in the taper shape. At the end of the venturi 103, there is a first throttle 55.

In the present embodiment, the first enlarged diameter portion 141 is provided at the tip of the first throttle portion 55. On the downstream side of the first enlarged diameter portion 141, there is a stable portion 143 having a substantially constant inner diameter shape, and further, a reduced diameter portion 145 having a tapered diameter is provided at the tip.
Then, there is a second throttle portion 142 that is the end of the reduced diameter portion 145, and there is a second diameter-expanded portion 146 whose inner diameter is increased in a taper shape with the second throttle portion 142 as a boundary. After that, the uniform cross section 57 has a uniform cross section. The flow path is linear from the gas inlet 43 to the first throttle part 55, the first enlarged diameter part 141, the reduced diameter part 145 and the like to the uniform cross section 57.
The end portion of the uniform cross section 57 is connected to the opening row portion 10 with the flow path bent vertically as in the previous embodiment.

The cross-sectional shape of each part of the flow path in the premixing member is as shown in FIG. That is, the cross-sectional area of the stable portion 143 is 1.2 to 3 times the cross-sectional area of the first throttle portion 55.
In other words, the cross-sectional area of the largest portion of the first enlarged diameter portion (enlarged portion) 141 is 1.2 to 3 times the cross-sectional area of the downstream end of the venturi portion 103.

  The cross-sectional area of the second throttle part 142 is 0.4 to 0.8 times the cross-sectional area of the stable part 143. That is, the cross-sectional area of the second throttle portion 142 is 0.4 to 0.8 times the cross-sectional area of the largest portion of the first enlarged diameter portion (enlarged portion) 141.

The spreading angle θ of the first enlarged diameter portion (enlarged portion) 141 is about 100 °. The recommended range of the spreading angle θ of the first enlarged diameter portion (enlarged portion) 141 is 90 ° to 180 °.
In this embodiment, since the cross-sectional shape of the first enlarged diameter portion (enlarged portion) 141 is substantially circular, the angle θ ′ with respect to the axis of each inner wall is 50 °, and the recommended range is 45 ° to 90 °. is there. When the cross-sectional shape of the first enlarged diameter portion (enlarged portion) 141 is a shape other than a substantially circular shape, it is desirable that any of the inner walls have the above-described relationship.

When the diameter of the gas inlet 43 is Ds, the distance A from the gas inlet 43 to the end of the first enlarged diameter portion (enlarged portion) 141 is in the range of 0.5 to 3 times.
When the diameter of the stable portion 143 is Dw, the distance B from the end of the first enlarged portion (enlarged portion) 141 to the second throttle portion 142 is in the range of 0.5 to 3 times.
reason

The inventors made a prototype of the premixing member 140 of the present embodiment using a transparent material and observed the flow of fuel gas and air inside, as shown in FIG. In other words, the concentration distribution in the cross-section B is substantially uniform as shown by the broken line in FIG.
In this manner, by adopting a structure in which the downstream side of the venturi portion 103 is temporarily enlarged, then reduced again, and further expanded again, the cross-sectional area through which the fuel gas flows can be increased, and the fuel and air can be expanded. Mixing can be facilitated. Therefore, the whole of the premixing member 140 and the combustion apparatus can be reduced in size.

  The cross-sectional shape of the flow path in the premixing member 140 is preferably circular, but may be oval or rectangular. For example, it may have a cross section close to a rectangle like the premixing member 140 shown in FIG.

The cross-sectional perspective view of the combustion apparatus which demonstrated the structure of the combustion apparatus of this invention typically. Sectional drawing of the combustion apparatus which demonstrated typically the structure of the flame-hole member vicinity of the combustion apparatus of this invention, and the flow of fuel gas, air, and a flame. Sectional drawing of the combustion apparatus which demonstrated typically the structure of the flame-hole member vicinity of the combustion apparatus of other Examples of this invention, and the flow of fuel gas, air, and a flame. Sectional drawing of the combustion apparatus which demonstrated typically the structure of the flame hole member vicinity of the combustion apparatus of further another Example of this invention, and the flow of fuel gas, air, and a flame. Sectional drawing of the combustion apparatus which demonstrated typically the structure of the flame hole member vicinity of the combustion apparatus of further another Example of this invention, and the flow of fuel gas, air, and a flame. The perspective view of the combustion apparatus in the practical Example of this invention. The top view at the time of accommodating the combustion apparatus of FIG. 6 in a case. AA sectional drawing of FIG. Sectional drawing of the combustion apparatus of FIG. The enlarged view of the site | part containing the top part vicinity of the flame hole member of FIG. The perspective view which fractured | ruptured the combustion apparatus of FIG. 6 in steps, and showed the internal structure. The disassembled perspective view of the combustion apparatus of FIG. FIG. 7 is an exploded sectional view of the combustion apparatus of FIG. 6 and a partially enlarged sectional view of a flame hole member. FIG. 7 is a perspective view of a premixing member of the combustion apparatus of FIG. 6. AA sectional drawing of FIG. BB sectional drawing of FIG. The perspective view of the air flow path member of the combustion apparatus of FIG. The enlarged view of the concave change part of the air flow path member of FIG. The perspective view of the flame hole member of the combustion apparatus of FIG. The front enlarged view of the ditch | groove part for a fitting of the flame hole member of FIG. The side view of the state which combined the flame hole member and the premixing member. The enlarged view of the base end part vicinity of the flame hole member of FIG. Explanatory drawing which shows the positional relationship of the opening of a premixing member, and the protruding item | line of an air flow path member. Explanatory drawing which shows the positional relationship of the opening of the premixing member in another Example, and the protrusion of an air flow path member. Explanatory drawing which shows the flow of the air in the air flow path member in a present Example. Explanatory drawing which shows the flow of the air in the air flow-path member in another Example. The enlarged view of the site | part containing the top vicinity of the flame hole member of the combustion apparatus in another Example. The model figure which shows the mixing effect | action of fuel gas and air in the premixing member employ | adopted in the Example shown in FIG. The perspective view which shows the modification of the premixing member employ | adopted with the combustion apparatus of this invention. FIG. 30 is a perspective view of the vicinity of the gas inlet of the premixing member in FIG. 29. FIG. 30 is a cross-sectional view showing a change in the flow path near the gas inlet of the premixing member in FIG. 29 and the cross-sectional shape of the flow path at each site. FIG. 30 is a cross-sectional view showing the inside of the vicinity of the gas inlet of the premixing member in FIG. 29. FIG. 30 is a graph showing a fuel gas concentration distribution in a specific cross section in the premixing member of FIGS. 28 and 29; The perspective view of the gas introduction port vicinity of the premixing member in another Example. Sectional drawing of the combustion apparatus which demonstrated typically the structure of the flame hole member vicinity of the combustion apparatus of a prior art, and the flow of fuel gas, air, and a flame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combustion device 2 Premixing member 3 Flame hole member 5 Air flow path member 25 Main body member 26 Flame holding wall 27 Side flame hole 30 Top surface part 43 Gas inlet 55 First throttle part 103 Venturi part 120 Step part (head part) )
121 Main flame hole 123 Flame holding 125 Main flame 122 Boundary 128 between stepped portion (head portion) and side wall portion Boundary 130 between stepped portion (head portion) and top surface portion Inclined portion 140 Premixing member 141 First enlarged diameter portion 142 Second restricting portion 143 Stabilizing portion 145 Reduced diameter portion 146 Second expanded diameter portion

Claims (8)

  A flame hole member and an air flow path member, and the air flow path member is wall-shaped and has an air discharge opening on the tip side, and the flame hole member is located between the two air flow path members or the air A first combustion part is formed by a space that is disposed between the flow path member and the other wall surface and is surrounded by the flame hole member and the air flow path member, and the oxygen-deficient fuel gas is first burned from the flame hole member. A combustion apparatus that is discharged to a part and combusts, and further combusts by receiving supply of air from an air discharge opening of an air flow path member, the flame hole member having a main body member and a flame holding wall, The member has a top surface portion and a side wall portion, a main flame hole is provided in the top surface portion of the main body member, and there is a drop portion between the top surface portion of the main body portion and the side wall portion of the main body portion, forming a flame holding shape. The wall is provided on the side surface of the main body, and the position of the protrusion of the flame-holding wall in the fuel gas flow direction is Is located on the upstream side of the boundary between the top surface and the side wall of the main body and the flame holding wall to form a side-side flame hole, and fuel gas is also released from the side-side flame hole And the air further flows in the vicinity of the side surface side flame hole of the flame hole member.   A flame hole member and an air flow path member, and the air flow path member is wall-shaped and has an air discharge opening on the tip side, and the flame hole member is located between the two air flow path members or the air A first combustion part is formed by a space that is disposed between the flow path member and the other wall surface and is surrounded by the flame hole member and the air flow path member, and the oxygen-deficient fuel gas is first burned from the flame hole member. A combustion apparatus that is discharged to a part and combusts, and further combusts by receiving supply of air from an air discharge opening of an air flow path member, the flame hole member having a main body member and a flame holding wall, The member has a top surface portion and a side wall portion, a main flame hole is provided in the top surface portion of the main body member, and there is a drop portion between the top surface portion of the main body portion and the side wall portion of the main body portion, forming a flame holding shape. The wall is provided on the side surface of the main body, and the position of the protrusion of the flame-holding wall in the fuel gas flow direction is Is located on the upstream side of the boundary between the side wall and the side wall of the main body and the flame-holding wall to form a side-side flame hole, and fuel gas is also released from the side-side flame hole And the air further flows in the vicinity of the side surface side flame hole of the flame hole member.   The combustion apparatus according to claim 1, wherein the head part is a step or an inclined surface.   The combustion according to any one of claims 1 to 3, wherein the flow velocity of the fuel gas discharged from the side-side flame hole is slower than the flow velocity of the fuel gas discharged from the main flame hole provided in the main body member. apparatus.   A premixing member for premixing the fuel gas and air inside, the fuel gas and air premixed by the premixing member flow to the flame hole member, and the premixing member includes fuel gas and air; The combustion according to any one of claims 1 to 4, further comprising: an introduction port through which gas is introduced; a venturi portion communicating with the introduction port; an enlarged portion communicating with the venturi portion; apparatus.   The combustion apparatus according to claim 5, wherein at least a part of the inner wall at the boundary between the venturi part and the enlarged part has an opening angle of 45 ° to 90 ° with respect to the axis.   7. The combustion apparatus according to claim 5, wherein the cross-sectional area of the largest portion of the enlarged portion is 1.2 to 3 times the cross-sectional area of the downstream end of the venturi portion. The cross-sectional area of the narrowed portion is 0.4 to 0.8 times the cross-sectional area of the largest portion of the enlarged portion. The combustion apparatus according to any one of claims 5 to 7, wherein

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