JPH0435689Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a premixed gas burner, and more particularly to a flame holding plate assembly for a surface combustion burner.

[Conventional technology]

A surface combustion burner, which is a type of premix gas burner, generates a short blue flame by ejecting a premixed mixture from a large number of small holes in a flame holding plate. Usually, flame arresters are installed to extinguish the flames moving backwards and prevent accidents such as ignition and explosions.

[The problem that the idea aims to solve]

By the way, in the conventional premix gas burner mentioned above, the combustion flame-holding plate and attached parts are exposed to high temperatures (usually
Since they will be exposed to flames at temperatures of 800 to 1000°C or higher, they must be made of highly heat-resistant ceramic materials.

Therefore, the following problems are known in conventional premixed gas burners, particularly in this type of flame stabilizing plate.

First of all, ceramics, which is the material of the flame-holding plate for combustion, has lower toughness and brittleness than metal materials, and is also less workable, so it is difficult to manufacture large-sized ceramics. Furthermore, for the reasons mentioned above, those with a structure in which the combustion surface faces downward have the problem that cracks form on the flame stabilizing plate surface and fall off from the surface layer, creating large holes.

Second, with conventional flame-holding plates for combustion, it is necessary to form powdered or granular ceramic materials into the desired shape by sintering or bonding, which not only increases costs but also addresses the reasons mentioned above. Together, they have a short service life.

Thirdly, increasing the amount of premixed air supplied to the flame stabilizing plate to increase the combustion surface load during combustion can prevent heating of the combustion flame stabilizing plate and backfire, but it causes a lift in the flame and inhibits combustion. Becomes unstable.

[Means to solve the problem]

This invention was made to solve the above problem, and includes a pair of perforated members that are parallel to each other, and a spherical member made of a heat-resistant material that is sandwiched between the window holes of the pair of perforated members. A premixing type gas burner comprising: each of the above-mentioned window holes is formed in a substantially rhombic shape, and the center of the inscribed circle of the window hole is formed to coincide with the vertical direction of the perforated member; shall have a smaller diameter than the diameter of the inscribed circle of each window hole, and be set so that the top of each spherical member is substantially flush with the surface of the perforated member when the spherical member is fitted into each window hole. This is a flame holding plate assembly for a premixed gas burner featuring the following.

[Effect]

According to a premixing type gas burner to which this idea is applied, the premixed air mixture flows through four large and small gaps formed by fitting a heat-resistant spherical member into the window hole of the perforated member, so that the premixed mixture faces each other. By ejecting, stable flame holding is possible.

〔Example〕

1 to 4 show an embodiment of a flame-holding plate assembly for a premixed gas burner according to this invention.

In the drawings, 1 indicates a perforated member and 2 indicates a spherical member.

The perforated members 1 are a set of two flat members made of iron, stainless steel, or other metal materials, and are arranged parallel to each other at a predetermined interval. Each of these perforated members 1 is provided with a large number of approximately diamond-shaped window holes 3, 3, arranged in a grid pattern with the same pitch.
For example, as shown in the figure, the shape is a diamond shape with a pair of opposing angles α of 60°.

The positional relationship between these window holes 3, 3 is as follows:
The centers of the inscribed circles of the diamond-shaped window holes 3, 3 are set to coincide with the vertical direction of the perforated members 1, 1.

The spherical member 2 is made of a heat-resistant material such as ceramic, and is held in a state in which it is fitted into each of the opposing window holes 3, 3 of the pair of perforated members 1. The diameter of each of these spherical members 2 is determined so that the top of each spherical member 3 is substantially flush with the surface of the perforated members 1, 1 when fitted into the window holes 3, 3. It is set between the circumscribed circle diameter and the inscribed circle diameter of 3. Therefore, when the spherical member 2 is fitted between the window holes 3 of the two perforated members 1, each window hole 3 is divided into four large and small gaps 3a and 3b, and these gaps 3a, 3b
On the fuel supply side, the premixture introduction hole,
On the combustion surface side, it functions as an injection hole for the premixture.

Here, it is assumed that the direction of supply of the premixture to the flame stabilizing plate A is from the bottom to the top in the figure, and that combustion occurs on the surface side of the upper perforated member 1.
The function of flame holding plate A will be explained.

First, as shown in FIGS. 2 and 3, in the window holes 3, 3 located above and below the spherical member 2, from the four large and small gaps 3a, 3b of each window hole 3, between the perforated members 1, 1, In addition, the premixed gas flowing toward the outside flows approximately tangentially along the surface of the spherical member 2.
At this time, the flow speed and amount of the premixed gas ejected from each of the large and small gaps 3a and 3b are different, and the flow directions are opposite to each other with the spherical member 2 in between. As a result, flames of different sizes are emitted from the large and small gaps 3a and 3b to the spherical member 2.
The same kind of things will be produced between them. This smaller flame acts as a wing for the larger flame, increasing flame retention similar to a flame retention burner. Therefore, the supply pressure of the premixture is high,
Stable flame holding is achieved without any lift phenomenon occurring in the flame during high-load combustion.

Furthermore, the air-fuel mixture that has flowed between the perforated members 1 and 1 from the gaps 3a and 3b becomes a flow that bends over a short distance between the inner sides of the perforated members 1 and 1, as shown in the figure. Even if the flame enters in the opposite direction, the flame is extinguished between the perforated members 1, 1, and explosion accidents caused by backfire can be suppressed. Furthermore, since a heat-resistant spherical member 2 is interposed between the perforated member 1 on the combustion surface side and the perforated member 1 on the premixture supply side, heat transfer between both perforated members 1 is improved. This can prevent the heat on the combustion surface from affecting the premixture supply side and causing ignition.

Furthermore, since the window hole is rhombic in shape as described above, the amount of thermal deformation at the periphery of the window hole 3 is different, and the holding force of the spherical member 2 exerted by the elasticity of the periphery of the window hole 3 is different. Because of the different diagonal directions of the window holes 3, it is possible to prevent the spherical member 2 from falling off even when the perforated member 1 on the combustion surface side is overheated by the radiant heat of the flame.

In the above explanation, two perforated members 1, 1
The window holes 3 formed in the respective windows overlap each other and face the same direction, but one window hole 3 is rotated by a predetermined angle with respect to the other window hole 3, for example, as shown in FIG. It may also be in a form rotated by 90 degrees.

Furthermore, the shape of the window hole 3 may be such that a round hole 4 is connected to at least one pair of opposing corners, as shown in FIG. Since the elasticity of the edge portion formed by this can be increased, the spherical member 2 can be held securely. Moreover, in this case, the premixture is ejected from the round hole 4 in a straight direction on the combustion surface, thereby improving flame stability.

Furthermore, the window hole 3 may have each side bulged toward the center to form a substantially star shape as shown in FIG. 7, and this also allows the spherical member 2 to be held more reliably.

[Effect of idea]

As explained above, in this invention, the premixed air blown out from the perforated member on the combustion side becomes a counterflow through four large and small gaps centered around each spherical member, and a flame is formed at the top of the spherical member. In order to
The small flame holds the large flame, and the combustion flame can be stably held without any lift.Furthermore, the perforated member is cooled by this premixture, which improves thermal durability. .

Moreover, a heat-resistant spherical member is interposed between the perforated member on the combustion surface side and the perforated member on the premixture supply side, so that the surface of the perforated member and the top of the spherical member are substantially flush with each other. Because it is set so that
The flame temperature near the perforated member surface can be suppressed to a low level, and at the same time, the combustion heat of this combustion flame is effectively prevented from being transferred toward the premixture supply side. Even when the premixture passes between the members, the flow is bent over a short distance, so that flashback can be effectively prevented.

In addition, the flame holding plate assembly for the premixed gas burner according to this invention has a simple structure and can maintain high strength, so it can be easily manufactured even if it is large. Since the spherical member is movable within each window hole,
It exhibits a self-cleaning action, reduces the number of maintenance inspections for clogging, etc., and can maintain stable performance over a long period of time.

Furthermore, since the window hole shape is approximately diamond-shaped,
Even if the perforated member on the combustion side becomes red hot due to the radiant heat of the combustion flame, etc., due to the fact that the holding force of the spherical member in each diagonal direction of the window hole is different and the amount of thermal deformation around the window hole is different. Thermal deformation can be suppressed to an extremely low level, and the spherical member can also be prevented from falling off from the window hole.

[Brief explanation of the drawing]

FIGS. 1 to 4 show an embodiment of a flame-holding plate assembly for a premixed gas burner according to this invention, and FIG. 1 is a plan view including a partially broken part;
Figure 2 is a sectional view taken along the - line in Figure 1, and Figure 3 is a
FIG. 4 is a sectional view taken along the line -- in FIG. 1, and FIG. 4 is a sectional view taken along the - line in FIG. FIG. 5 is a partially broken plan view showing another embodiment. FIGS. 6 and 7 are partial plan views showing still other embodiments in which the window hole shapes are different. A... Flame holding plate, 1... Perforated member, 2... Spherical member, 3... Window hole.

Claims (1)

[Claims for Utility Model Registration] A pair of perforated members 1, 1 parallel to each other,
A premixing type gas burner consisting of spherical members 2, 2... formed of a heat-resistant material sandwiched between window holes 3, 3... of these pair of perforated members 1, 1, each of the window holes 3 , 3... are formed into a substantially rhombic shape, and the centers of the inscribed circles of the window holes 3, 3... are formed to coincide with the vertical direction of the perforated members 1, 1, and each of the above-mentioned spherical members 2, 2... , the diameter is smaller than the diameter of the inscribed circle of each window hole 3, 3..., and the spherical member 2, 2...
The premixing device is characterized in that the top of each spherical member 2, 2... is set to be substantially flush with the surface of the perforated member 1, 1 when the spherical member 2, 2... is fitted into each window hole 3, 3... Flame holding plate assembly for type gas burner.