JP2001000849A - Premixer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a premixer for performing secondary mixing for the purpose of micro mixing to primary mixed gas that fuel gas and combustion air are macro mixed to reduce NOx production on combustion and to prevent backfire. SOLUTION: This premixer is, in a premixer for premixing fuel gas and combustion air before the fuel gas is burned, constituted of a feeding duct 2 for blowing and feeding air, a fuel gas feeding means 6 for jetting the fuel gas to an air flow in the feeding duct 2 in an orthogonal state to primarily mix the two, and a mixing promoting body 10 for secondary mixing arranged in a position on the downstream side from the primary mixing point. The mixing promoting body 10 consists of an upstream side conic body 12 having an apex 12a in the upstream direction, a cylindrical body 14 provided successively to the upstream side conic body 12 and installed almost parallel to the feeding duct 2, and a downstream side conic body 16 provided successively to the cylindrical body 14 and having an apex 16a in the downstream direction. In an annular clearance part 18 formed between the cylindrical body 14 and the feeding duct 2, micro uniform secondary mixed air is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premixing apparatus for use in a combustion apparatus such as a hot-water boiler, a flue-tube boiler, a cyclone-type ash melting apparatus, etc., which premixes gaseous fuel and combustion air. More specifically, the present invention relates to a premixing device for uniformly mixing gas fuel and combustion air into a micro region.

[0002]

2. Description of the Related Art In general, in a premixed combustion system in which fuel gas and combustion air are separately supplied and mixed by a combustion burner, the fuel gas and combustion air are mixed while diffusing, resulting in uniform mixing of the two. Was difficult to obtain. Therefore, since the mixture is burned while the rich mixture and the lean mixture are formed, a locally high combustion temperature is formed. Among thermal NOx, thermal NOx is greatly affected by temperature. Therefore, if a high-temperature portion exists locally, the NOx generation rate during combustion increases.

[0003] Therefore, in a combustion apparatus such as a hot water boiler, a flue-tube boiler, and a cyclone ash melting apparatus, a premixing method in which fuel gas and combustion air are mixed before combustion has been adopted. In this premixing method, since the fuel gas and the combustion air are uniformly mixed in advance, the maximum combustion temperature is low, and the generated NOx can be kept low.

[0004] However, in the conventional premixing device, the fuel gas and the combustion air can be macroscopically and uniformly mixed, but it has been difficult to homogenize to a micro level. As a result, the combustion temperature is not stable, and the occurrence of a local high-temperature portion in the combustion region has been the limit of NOx reduction.

For example, FIG. 17 shows a premix combustion device disclosed in Japanese Patent Application Laid-Open No. 8-86417. The fuel gas 8 is orthogonal to the combustion air 82 supplied by the blower 80.
4 is ejected from the fuel gas supply pipe 86. By this fluid collision, the combustion air 82 and the fuel gas 84 are macro-primarily mixed, and after flowing in the direction of the arrow, the primary air-fuel mixture 88 is burned. In this device, even though macro-mixing is performed by fluid collision, micro-mixing of combustion air and fuel gas at the molecular level is not performed, which is a limit of NOx reduction. Also, the remaining non-uniformity of the mixing causes a flashback, that is, a phenomenon in which the flame flows back into the combustion nozzle.

FIG. 18 shows a premixing device disclosed in JP-A-6-74423. The combustion air 82 supplied by the blower 80 is swirled by the swirling flow forming means 81,
Fuel gas is ejected orthogonally to the swirling flow from the ejection hole 90 of the fuel gas supply pipe 86. The primary mixture 88 macro-mixed by this ejection reaches the large-diameter portion 92.

However, in the large-diameter portion 92, the macro mixing by the vortex as shown in the figure is performed in the peripheral portion, but the micro mixing is not performed. In other words, macro-mixing has already been performed at the time of formation of the primary air-fuel mixture 88, and what should be performed next is local micro-mixing at various points in the fluid. It must be said that this prior art is still insufficient in that this micro-mixing has not been performed.

FIG. 19 shows a premixed combustion apparatus disclosed in Japanese Patent Laid-Open No. Hei 5-231615. A primary air-fuel mixture in which fuel gas and combustion air are already mixed is introduced through a pipe 94 through an inlet 95.
Inflows from. The primary air-fuel mixture collides with the turbulent flow generating member 96 in the form of a flat plate, and a Karman vortex 97 is generated from the upper and lower edges as shown in FIG. The turbulent mixture is burned by the igniter 99.

The turbulence generating member 96 generates a large Karman vortex as shown in the drawing, and it is almost impossible to micromix the primary air-fuel mixture at the molecular level. The point of mixing and stirring again using turbulence is moving forward, but has not reached the level of micromixing.

FIG. 20 is a view similar to that of JP-A-5-23161.
Fig. 5 is another premixed combustion device disclosed in Japanese Patent Publication No. 5 (JP-A-5) The difference from FIG. 19 is that a cone is used as the turbulence generating member 96. However, in the case of such a large cone, a large Karman vortex street is generated at the periphery, and micro mixing is impossible even if macro mixing can be performed as in FIG.

[0011]

As described above, a technique has been almost established in which a fuel gas is ejected and collided orthogonally with a combustion air flow so as to macroscopically mix the two. However, in this primary gas mixture, macro mixing and stirring are performed, but micro mixing for stirring air and gas at a molecular level is not performed.

Further, a technique has been developed in which the primary air-fuel mixture is further mixed and stirred to obtain a secondary air-fuel mixture. However, micro-mixing was not possible because the secondary mixing means was intended to generate large vortices or large Karman vortices. Attempts were made to increase the flow rate for micromixing, but the pressure drop increased rapidly and micromixing could not be performed satisfactorily. There was also a limitation of the blower for increasing the flow velocity.

Accordingly, it is an object of the present invention to provide a premixing apparatus for uniformly and micromixing a primary mixture which has been macromixed. Accordingly, it is an object of the present invention to provide a premixing device capable of lowering the combustion temperature of the secondary air-fuel mixture to reduce the amount of NOx generated, and preventing flashback in which the combustion flame flows back into the combustion device.

[0014]

A first premixing device according to the present invention comprises a supply duct for supplying air and a fuel gas which is blown at right angles to the air flow in the supply duct to form a mixture. It is composed of a fuel gas supply means for primary mixing, and a mixing promoting body for secondary mixing disposed downstream of the primary mixing point, and the mixing promoting body is an upstream cone having an apex in an upstream direction. A cylindrical body connected to the upstream cone and provided substantially parallel to the supply duct, and a downstream cone connected to the cylindrical body and having an apex in a downstream direction. Is characterized in that a micro-uniform secondary air-fuel mixture is formed in an annular gap formed between the air and the supply duct.

Further, the second premixing device includes a supply duct for blowing air, and a fuel gas supply means for ejecting the fuel gas orthogonally to the air flow in the supply duct to firstly mix the two. And a mixing promoting body for secondary mixing disposed at a position downstream from the primary mixing point and having both right and left ends close to the supply duct, and the mixing promoting body is an upstream side having a top line in the upstream direction. A triangular prism portion, a rectangular parallelepiped portion connected to the upstream triangular prism portion and provided substantially parallel to the supply duct, and a downstream triangular prism portion connected to the rectangular parallelepiped portion and having a top line in the downstream direction, A micro-uniform secondary air-fuel mixture is formed in a pair of upper and lower rectangular gaps formed between the section and the supply duct.

In the first and second premixing devices, a premixing device in which a rectifier is disposed in the gap is proposed.

The third premixing device includes a supply duct for supplying air, a fuel gas supply means for injecting a fuel gas at right angles to the air flow in the supply duct, and primary mixing the two, At a position downstream of the primary mixing point, there are a plurality of substantially equally spaced mixing accelerators arranged orthogonally to the primary air-fuel mixture. It consists of angles arranged in a character shape, characterized in that a micro-uniform secondary air-fuel mixture is formed by both shaped pieces with the top line of the mixing promoting body facing upstream.

In the third premixing device, there is proposed a premixing device in which a plurality of cut pieces are formed by making zigzag-shaped notches in the edge of the shape piece of the mixing promoting body.

In the premixing device, the fuel gas supply means includes a plurality of gas ejection holes formed in a circumferential direction of the supply duct and a gas annular body which hermetically covers these gas ejection holes. We propose a premixing device that supplies gas into the body and ejects gas from gas ejection holes.

In the premixing device, the fuel gas supply means includes a gas supply cylinder provided in a diameter direction of the supply duct and a plurality of gas ejection holes formed in a side surface of the gas supply cylinder in an axial direction. In other words, we propose a premixing device in which gas ejection holes are arranged so that the gas ejection direction is orthogonal to the air flow.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to FIGS. 1 to 3 show a first embodiment of a premixing device according to the present invention. In particular, FIG. 1 is a longitudinal sectional view thereof, and FIG. 3 is a sectional view taken along line AA of FIG. Combustion air is supplied in a direction indicated by an arrow a from a blower (not shown) through a supply duct 2 having a circular cross section. A number of gas ejection holes 4 are formed in the circumferential direction of the supply duct 2, and a gas annular body 6 that airtightly covers the gas ejection holes 4 from the outside is provided. The fuel gas is supplied from the gas pipe 8 in the direction of arrow b, and the gas annular body 6 becomes a gas reservoir and blows out in the direction of arrow c through the gas ejection hole 4.

At the axial position of the supply duct 2, the mixing promoting body 1
0 is arranged. As is clear from FIG. 2 which is a perspective view of the mixing promoting body 10, the mixing promoting body 10 has a vertex 1 in the upstream direction.
An upstream cone 12 having a top 2a; a cylinder 14 connected to the upstream cone 12 and substantially parallel to the supply duct 2; and a downstream having an apex 16a in the downstream direction connected to the cylinder 14. And the side pyramid 16. In this embodiment, the cylinder 14 is a cylinder, and the cones 12 and 16 are formed as cones.

It is desirable that the mixing accelerator 10 be disposed such that the vertex 12 a of the upstream cone 12 is located downstream of the gas outlet 4. After the primary mixing, the setting is made such that the radiation is dispersed by the cones 12. An annular gap 18 is formed between the cylindrical body 14 and the supply duct 2, and a rectifier 20 is fitted into the annular gap 18 to fix the mixing promoting body 10 in the supply duct 2. are doing.

The apex angle θ ₁ of the upstream cone 12 is set to a large angle of 80 ° to 150 °, preferably 90 ° to 120 °, in order to promote primary mixing. The annular gap 18 is a region in which the primary air-fuel mixture is micro-mixed, and its thickness T is desirably as small as possible, and its length L is desirably as long as possible. Therefore, the cylinder length L is set longer than the cylinder diameter D. While traveling through the thin and long gap 18, micro-mixing and micro-stirring of fuel gas molecules and combustion air molecules are performed.

If the rectifier 20 is fitted into the gap 18, the micromixing action of the gap 18 can be further forcibly assisted. The rectifier 20 may be formed of, for example, a net or a honeycomb structure. Further, in order to effectively perform the secondary mixing, that is, the micro mixing, it is desirable that the flow rate of the air-fuel mixture flowing through the gap 18 is as high as 10 m / s or more.

The apex angle θ _O of the downstream cone 16 is set to a small angle of 60 ° to 90 ° in order to keep the laminar flow state of the micro-mixed primary mixture, ie, the secondary mixture, as much as possible. Preferably, the smaller the angle, the longer the total length of the mixing promoting body 10.

Next, the operation of the first embodiment will be described. After the fuel gas supplied in the direction of the arrow b fills the entire gas annular body 6, it is ejected from the many gas ejection holes in the direction of the arrow c. The fuel gas collides with the combustion air supplied in the direction of the arrow a in a direction orthogonal to the fluid, and while being primarily mixed in a large turbulent state, the slope of the upstream cone 12 around the apex 12a in the direction of the arrow d. Going up. Turbulent agitation of the primary air-fuel mixture is promoted even on this large-angled slope.

The primary air-fuel mixture that has reached the annular gap 18 is
In the relatively thin gap, internal fluid friction occurs with each other, and at the same time, fluid friction also occurs from the surfaces of the supply duct 2 and the cylindrical body 14. Micro-mixing is performed at various points in the primary air-fuel mixture by these fluid frictions. Further, the rectifying action of the rectifier 20 accelerates the micro-mixing, and a very uniformly uniform secondary air-fuel mixture is formed through the secondary mixing.

The uniform secondary air-fuel mixture flows through the supply duct 2 while diverging in the direction of arrow c by the downstream cone 16 and is sent to a downstream combustion section (not shown). Apex angle θ _O
Is set to a small angle, the secondary air-fuel mixture is sent to the combustion section in a laminar state without forming a vortex.

Therefore, since the secondary air-fuel mixture uniformly micro-mixed is combusted in the combustion section, the combustion temperature is extremely uniform and uniform, and the combustion temperature is lowered as a whole to generate NOx. The reduction can be achieved reliably. This leads to prevention of flashback. Further, since micro mixing can be performed structurally and structurally with this apparatus, micro mixing can be realized even if the flow rate of the air-fuel mixture is reduced. The reduction in the flow velocity also has the effect of reducing the pressure loss.

In order to increase the axial symmetry of the mixed flow in the annular gap 18, the mixing promoting body 10 is formed by combining a conical body and a cylindrical body. As long as it is satisfied, the mixing promoting body 10 may be formed by a polygonal pyramid or a polygonal cylinder.

FIGS. 4 to 6 show a second embodiment of the premixing device according to the present invention. 4 is a longitudinal sectional view, FIG. 5 is a perspective view of a mixing promoting body, and FIG. 6 is a sectional view taken along line BB of FIG. In the description of the second embodiment, the same portions as those of the first embodiment are denoted by the same reference numerals, the description thereof will be simplified, and different portions will be described in detail.

The cross section of the supply duct 2 is rectangular, and a rectangular gas ring 6 is provided surrounding the periphery thereof. The mixing promoting body 10 includes an upstream triangular prism portion 22 having a top line 22 a in the upstream direction, a rectangular parallelepiped portion 24 connected to the upstream triangular prism portion 22 and provided substantially parallel to the supply duct 2, 24, a downstream triangular prism portion 26 having a top line 26a in the downstream direction.

The left and right ends of the mixing accelerator 10 are in close contact with the left and right inner surfaces of the supply duct 2. Therefore, the space formed between the rectangular parallelepiped portion 24 and the supply duct 2 is a pair of vertically spaced gap portions 18 having a rectangular cross section. Rectifiers 20, 20 are mounted in these gaps 18, 18, respectively. Further, the gas ejection ports 4 are not formed on the left and right wall surfaces of the supply duct 2, but are formed only on the upper and lower wall surfaces as shown in the figure.

The relationship between the arrangement position of the apex line 22a, the range of the apex angles θ ₁ and θ _O , and the thickness D of the rectangular parallelepiped portion 24 is the same as that of the first embodiment, and will not be described. However, it is desirable that the rectangular parallelepiped portion length L be equal to or larger than the width W of the supply duct 2.

The operation of the second embodiment will be briefly described. The fuel gas ejected in the direction of the arrow c collides fluidly with the combustion air flowing in the direction of the arrow a and undergoes primary mixing to form a large turbulent flow. This turbulent flow splits up and down the steep slope of the upstream triangular prism portion 22, and the primary mixing is completed in this process.

The primary air-fuel mixture which has flowed up and down enters the upper and lower gaps 18 and 18, and micro-mixing occurs due to friction caused by the wall surface and growth of the boundary layer. Micro-mixing and micro-stirring are promoted by the action of the rectifiers 20, 20, and the rectifiers 20, 2
Secondary mixing ends near the exit of 0, and uniform secondary mixing ends. The upper and lower secondary air-fuel mixtures are joined by the gentle slope of the downstream triangular prism portion 26 so as not to form a vortex, and sent to the rear combustion portion. Since the effect is the same as that of the first embodiment, the description is omitted.

FIGS. 7 to 9 show a third embodiment of the premixing device according to the present invention. 7 is a longitudinal sectional view, FIG. 8 is a perspective view of a mixing promoting body, and FIG. 9 is a sectional view taken along line CC of FIG. In describing the third embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
Explain the different parts in detail.

The third embodiment is different from the first embodiment in the shape of the mixing promoting body 10. As can be seen from FIG. 8, the mixing promoting body 10 has two shape pieces 28, 28 at an angle angle θ.
And the angle θ is 60 ° to 1
00 °, preferably 80 ° to 100 °. Shape piece 28
Width L ₁ of 30mm or less, preferably 10~20mm
It is.

A plurality of the angle-shaped mixing promoters 10 are arranged at equal intervals over the entire length of the cross-section of the supply duct 2 so that the top line 30 faces upstream. If the interval L ₃ is the angle width L _2, it is set to _{0.5L 2 <L 3 <2L 2} . In addition, if L ₂ is reduced and as many mixing promoters 10 as possible are arranged, the efficiency of micro mixing increases.

The distance L ₀ between the gas ejection hole 4 and the mixing promoting body 10 is preferably as long as possible, but it is desirable that L ₀ > 0.5D _{0 as} compared with the diameter D ₀ of the circular supply duct. . In order to ensure the secondary mixing (micro mixing), the flow rate of the air-fuel mixture at the position of the mixing accelerator 28 is 10 m.
/ S or more is desired. When the flow rate is high, when a large the distance L _3, 2-order mixing is effective.

Next, the operation of the third embodiment will be described. As can be seen from FIGS. 7 and 9, the fuel gas is ejected from the ejection port 4 through the gas ring 6 in the direction of arrow c. The combustion air in the direction of arrow a is primarily mixed in a large turbulent state with the fuel gas which collides with the fluid orthogonally. The primary air-fuel mixture gradually becomes a stable flow from a large turbulent state, and this process is called macro mixing.

As shown by the arrow f, this primary air-fuel mixture diverges right and left from the top line 30 of the mixing promoting body 10, and forms a minute Karman vortex at its edges 28a, 28a while climbing the shape piece 28. I do. Since this Karman vortex is minute, it gradually becomes stable in the downstream flow process and becomes a uniformly uniform secondary mixed flow g. Mixing after the mixing promotion body 10 with micromixing, the angle width L ₂ of the mixing promotion body 10 and smaller when more sequences number, micromixing is performed more finely.

FIGS. 10 to 13 show a fourth embodiment of the premixing device according to the present invention. FIG. 10 is a longitudinal sectional view, FIG.
1 is a perspective view of a mixing promoting body, FIG. 12 is a perspective view of another mixing promoting body, and FIG. 13 is a sectional view taken along line EE of FIG. In the description of the fourth embodiment, the same parts as those of the third embodiment will be denoted by the same reference numerals, and the description thereof will be omitted, and different parts will be described.

The fourth embodiment differs from the third embodiment in that the cross section of the supply duct 2 is rectangular and that the angle of the mixing promoting body 10 is slightly different. The point that the cross section of the supply duct 2 is rectangular is the same as that of the second embodiment, and a description thereof will be omitted.

The mixing accelerator 10 shown in FIG.
A large number of cut pieces 32 are formed by making zigzag notches in a. Both ends of the cut piece 32 are edges 3
2a, so that twice as many edges 32a as the cut pieces 32 are formed on one shape piece 28. In this example, since the edge 28a is left in the cut piece 32,
The number of edges 32a is small.

In the mixing promoting body 10 shown in FIG.
Since the cut is made until the 8a is completely lost, an extremely large number of cut pieces 32 can be formed, and as a result, the number of edges 32a can be increased rapidly.

When the primary air-fuel mixture comes to the mixing accelerator 10 shown in FIG. 11 or FIG. 12, as shown by the arrow f,
First, the shunts are diverted upward and downward by the shape pieces 28, 28, and the respective shunts are further diverted to the left and right by the edges 32 a, 32 a of the cut pieces 32 to form minute Karman vortices. If there are many cut pieces 32, a large number of extremely small Karman vortices are formed,
At a stage where the flow has slightly flowed down, a uniform and uniform secondary mixed flow g is formed.

FIGS. 14 to 16 show a fifth embodiment of the premixing device according to the present invention. FIG. 14 is a longitudinal sectional view, FIG.
5 is a sectional view taken along line FF of FIG. 14 and FIG.
It is a G line sectional view. In describing the fifth embodiment, the same parts as those of the fourth embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Different parts will be described.

This fifth embodiment shows another embodiment of the fuel gas supply means.
The gas supply tube 7 is provided in the diameter direction of the supply duct 2 so as to be internally provided. At a position orthogonal to the air supply direction a on the side surface of the gas supply cylinder 7, a number of gas ejection holes 4 are formed in the axial direction thereof, and eject fuel gas in the direction of arrow c.

In this embodiment, since the gas supply cylinder 7 is located at the center in the supply duct 2, the gas supply cylinder 7 has a surface in which the flow of combustion air is disturbed. Will be held on both sides. When the primary mixed flows on both sides also slightly flow down, they fuse with each other, and
After the next mixing, the same operation and effect as those of the fourth embodiment are obtained, and the description thereof is omitted.

The present invention is not limited to the above-described embodiment, but includes various modifications and design changes within the technical scope thereof without departing from the technical concept of the present invention.

[0053]

According to the first aspect of the present invention, the fuel gas and the combustion air are firstly mixed macroscopically using, for example, a supply duct having a cylindrical cross section, and then this primary air-fuel mixture is microscopically mixed. Since they can be mixed, a uniform and uniform mixture can be generated. Therefore, even if this air-fuel mixture is burned, there is no unevenness in the combustion temperature, NOx can be reduced, flashback can be prevented, and uniform mixing with low pressure loss is possible.

According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained by using a supply duct having a rectangular cross section, for example.

According to the third aspect of the present invention, since the rectifier is disposed in the gap having an annular cross section or a rectangular cross section, secondary mixing, which is micro mixing, can be promoted or accelerated.
Reduction, flashback prevention and low pressure loss mixing can be made more efficient.

According to the fourth aspect of the present invention, in a supply duct having an arbitrary cross-sectional shape, micro-secondary mixing can be performed on a primary air-fuel mixture. The effect of fire prevention and low pressure loss mixing can be provided.

According to the fifth aspect of the invention, the efficiency of the fourth aspect of the invention can be further improved.

According to the sixth aspect of the present invention, since the fuel gas supply means is not provided in the supply duct, the primary mixing of the fuel gas and the combustion air can be performed in a wide place, and there is no possibility of mechanical disturbance. Since there is no primary mixing, higher efficiency of the primary mixing can be achieved.

According to the seventh aspect of the present invention, the structure of the fuel gas supply means is simple and easy to manufacture. Further, since the air flow velocity near the gas ejection part is high, the primary mixing and the secondary mixing can be reliably performed even when the supply pressure of the fuel gas is low.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a premixing device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a mixing promoting body of the first embodiment.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a longitudinal sectional view of a premixing device according to a second embodiment of the present invention.

FIG. 5 is a perspective view of a mixing promoting body according to a second embodiment.

FIG. 6 is a sectional view taken along line BB of FIG. 4;

FIG. 7 is a longitudinal sectional view of a premixing device according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a mixing promoting body of a third embodiment.

FIG. 9 is a sectional view taken along the line CC of FIG. 7;

FIG. 10 is a longitudinal sectional view of a premixing device according to a fourth embodiment of the present invention.

FIG. 11 is a perspective view of a mixing promoting body according to a fourth embodiment.

FIG. 12 is a perspective view of another mixing promoting body of the fourth embodiment.

FIG. 13 is a sectional view taken along line EE of FIG. 10;

FIG. 14 is a longitudinal sectional view of a premixing device according to a fifth embodiment of the present invention.

FIG. 15 is a sectional view taken along line FF of FIG. 14;

FIG. 16 is a sectional view taken along line GG of FIG. 14;

FIG. 17 is a perspective view of a first conventional example of a premixed combustion device.

FIG. 18 is a sectional view of a main part of a second conventional example of a premixing device.

FIG. 19 is a sectional view of a third conventional example of a premixed combustion device.

FIG. 20 is a sectional view of a fourth conventional example of a premixed combustion device.

[Explanation of symbols]

2 is a supply duct, 4 is a gas outlet, 6 is a gas ring, 8
Is a gas pipe, 10 is a mixing promoter, 12 is an upstream cone, 12
a is a vertex, 14 is a cylinder, 16 is a downstream cone, 16a is a vertex, 18 is a gap, 20 is a rectifier, 22 is an upstream triangular prism, 22a is a top line, 24 is a rectangular parallelepiped, and 26 is downstream. Side triangular prism portion, 26a is top line, 28 is shape piece, 28a is edge, 30
Is a top line, 32 is a cut piece, 32a is an edge, 80 is a blower, 82 is combustion air, 84 is a fuel gas, 86 is a fuel gas supply pipe, 88 is a primary air-fuel mixture, 90 is an ejection hole, and 92 is an ejection hole. A large diameter portion, 94 is a conduit, 95 is an inlet, 96 is a turbulence generating member, 97 is a Karman vortex, 98 is a turbulent region, and 99 is an igniter.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission Date] July 13, 2000 (2007.1)
3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

A uniform secondary mixture is produced by the downstream cone 16.
The air flows in the supply duct 2 while spreading in the direction of the arrow e , and is sent to a downstream combustion section (not shown). Apex angle θ ₀
Is set to a small angle, the secondary air-fuel mixture is sent to the combustion section in a laminar state without forming a vortex.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

Therefore, since the secondary air-fuel mixture uniformly micro-mixed is combusted in the combustion section, the combustion temperature is extremely uniform and uniform, and the combustion temperature is lowered as a whole to generate NOx. The reduction can be achieved reliably. This leads to prevention of flashback. Further, since micro mixing can be performed structurally with this apparatus, micro mixing can be realized even when the flow rate of the air-fuel mixture is reduced. The reduction in the flow velocity also has the effect of reducing the pressure loss.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

When the primary air-fuel mixture comes to the mixing accelerator 10 shown in FIG. 11 or FIG. 12, as shown by the arrow f,
First, the flow is divided up and down by the shape pieces 28, 28, and each of the divided flows is further divided right and left by the edges 32 a, 32 a of the cut pieces 32 to form minute Karman vortices. If there are many cut pieces 32, a large number of extremely small Karman vortices are formed,
At a stage where the flow has slightly flowed down, a uniform and uniform secondary mixed flow g is formed.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Isao Kuwagaki, Inventor 600-1, Kuzedonojo-cho, Minami-ku, Kyoto-shi, Kyoto Prefecture F-term (reference) 3K017 CA05 CB08 CD02 CE03 4G035 AB02 AC01 AC19 AC55 AE13 4G036 AC65

Claims (7)

[Claims] In a premixing device for mixing fuel gas and combustion air before burning, a supply duct for supplying air and a fuel gas are injected orthogonally to an air flow in the supply duct. Fuel gas supply means for primary mixing the two, and two fuel gas supply means disposed downstream of the primary mixing point.
The mixing promoting body is composed of a mixing promoting body for the next mixing, the mixing promoting body has an upstream cone having an apex in the upstream direction, and a cylindrical body connected to the upstream cone and provided substantially parallel to the supply duct. And a downstream cone connected to the cylindrical body and having a vertex in the downstream direction. A micro-uniform secondary air-fuel mixture is formed in an annular gap formed between the cylindrical body and the supply duct. A premixing device characterized by forming. 2. A premixing device for premixing fuel gas and combustion air prior to combustion, wherein a supply duct for blowing air is supplied, and the fuel gas is injected orthogonally to an air flow in the supply duct. A fuel gas supply means for primary mixing of the two, and a mixing accelerator for secondary mixing disposed downstream of the primary mixing point and having both left and right ends in close contact with the supply duct. Is an upstream triangular prism portion having a top line in the upstream direction, a rectangular parallelepiped portion connected to the upstream triangular prism portion and provided substantially parallel to the supply duct, and a top line in the downstream direction connected to the rectangular parallelepiped portion. A premixing comprising a downstream triangular prism portion having a micro-uniform secondary air-fuel mixture formed in a pair of upper and lower rectangular cross sections formed between the rectangular parallelepiped portion and the supply duct. apparatus. 3. A rectifier is disposed in the gap.
Or the premixing device according to 2. 4. A premixing device for premixing fuel gas and combustion air prior to combustion, wherein a supply duct for blowing air is supplied, and the fuel gas is injected orthogonally to an air flow in the supply duct. A fuel gas supply means for primary mixing the two, and a plurality of substantially equally spaced mixing promoters disposed at a position downstream of the primary mixing point and orthogonal to the primary mixed gas flow. The mixing promoting body is composed of an angle in which two pieces are arranged in a substantially V-shaped cross section.
A premixing device for forming a secondary air-fuel mixture. 5. The pre-mixing device according to claim 4, wherein a plurality of cut pieces are formed by making zigzag-shaped notches in an edge of the shape piece of the mixing promoting body. 6. The fuel gas supply means includes a plurality of gas ejection holes formed in a circumferential direction of a supply duct, and a gas annular body which hermetically covers these gas ejection holes, and supplies gas into the gas annular body. The premixing device according to claim 1, wherein the gas is supplied and supplied from a gas ejection hole. 7. The fuel gas supply means includes a gas supply cylinder provided in a diameter direction of a supply duct, and a large number of gas ejection holes formed in a side surface of the gas supply cylinder in an axial direction. 6. The premixing device according to claim 1, wherein the direction is orthogonal to the air flow.