JPH0336411A - Flame holding body for gas burner of premixing type - Google Patents

Abstract

PURPOSE:To form stable flames by providing many projection on the surface of a flame holding body which injects a premixture gas from many injection holes provided in the flame holding body and forming combustion flames on its surface. CONSTITUTION:A flame holding body 10 of a flat plate shape, made of ceramics, etc., which has many injection holes 11 formed is provided with many projections 20 on the side of the combustion face. The projection 20 has a shape provided with a head section 21 of flat sphere shape and a neck section 22 of a columnar shape. As the speed of injection of a premixture gas from the injection hole 11 is raised, vortex flows are created on the back side of the head section 21 of the projections 20, and small flames are formed so as to be covered on both sides by large flames. In these conditions, even if the speed of injection of the premixture gas goes in the range of speed in which flames of conventional burners for premixture gases are lifted or blown off, the flames downstream of the projections 20 are held stably, and the flames downstream of the injection holes 11 are successively ignited by the flames and the whole burner flames are always held stably.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a flame stabilizer for a premixed gas burner, specifically,
The present invention relates to an improvement of a flame stabilizer for a surface combustion burner having a large number of premixture injection holes.

[Conventional technology]

In recent years, due to environmental issues such as air pollution, gas fuels such as city gas and LPG, which have very few harmful components in the combustion gas, are increasingly being used industrially, and gas burners are also being used in thermal equipment such as boilers. is increasing.

One type of these gas burners is the surface combustion burner.
As shown in FIGS. 8 and 9, for example, a burner with this structure allows fuel gas to flow out through a flame stabilizer (2) in which a large number of micropores (1) are formed, and the flame stabilizer (2) It is formed to generate many small flames on the surface.

[Problem to be solved by the invention]

By the way, in the birch surface combustion burner mentioned above, when the supply pressure of the premixture is increased to achieve high-load combustion,
Due to the increase in the ejection velocity of the premixture from the micropores (1) on the surface of the flame stabilizer (2), the micro flames on the surface of the flame stabilizer (2) become lifted and are finally blown out.The reason This is because, as is well known, combustion reaction occurs in a region where the injection speed of the premixture and the combustion speed are balanced.

Furthermore, this type of burner also has the problem that upon ignition, the flame instantly spreads over the entire surface of the surface combustion burner, resulting in a large impact upon ignition.

For these reasons, at present, a small-sized, high-load combustion type, surface combustion burner capable of stable combustion has not been technically achieved, and there is an increasing demand from the market for this type of burner.

[Means to solve the problem]

The present invention was made to meet the above requirements, and includes a device in which a premixture is ejected from a large number of nozzles provided in a flame stabilizer to form a combustion flame on the surface of the flame stabilizer. , a flame-holding temporary for premixed gas burners that is dotted with numerous protrusions.

[Effect]

According to the flame stabilizer for a premixed gas burner according to the present invention,
Even if the supply pressure of the premixture is high and the flame lifts or blows out in conventional gas burners, the back side of the protrusion (
Since the premixture is continuously ignited by small flames formed in the wake of the jet, a flame is stably formed in the wake of the nozzle and the flame is stabilized.

[Embodiment] FIGS. 1 to 3 show an embodiment of a premixing gas burner according to the present invention.

In those drawings, 00) is a flat plate-shaped flame stabilizer made of ceramic or the like in which a large number of nozzle holes OD are formed, and the difference from the conventional one is that a large number of protrusions 121B are provided on the combustion surface side. It is in.

Above protrusion C! In this example, Φ is the oblate spherical head Q
1 and a columnar neck (2).

These protrusions Q (D may be formed integrally with the flame stabilizer 0 (1), but more realistically, a nail-like member having the shape described above is formed and attached to the flame stabilizer 00). The desired number of screws can be driven in, or a screw-shaped member having the shape described above can be formed, penetrated through the flame stabilizer 00, and fixed with a nut by sandwiching the flame stabilizer 00). be able to.

In the above configuration, the combustion situation will be explained next.

First, during combustion under normal load, the gas jetting speed from the nozzle hole (11) is low, and the fire field formed is also a short flame.

In this state, as shown in Figure 3(a), a vortex of the premixture is generated at the base of the protrusion, and this vortex promotes the combustion reaction of the flame, causing fluctuations in the supply pressure of the premixture. Even if this occurs, the combustion state remains stable.

Next, when the supply pressure of the premixture is increased from the above combustion state, the above flame length becomes longer. However, in the flame stabilizer 00) according to the present invention, as the speed of the premixture jetting out from the jetting hole 01) increases, a vortex is generated on the back side of the head of the protrusion 121, which is caught between the large flames on both sides. A small flame is formed. Assume that in this state, the ejection velocity of the premixed gas has entered a range where it would lift or blow out in a conventional premixed burner. Even in this ejection velocity range, the flame downstream of the projection 12G is stably held for the reason mentioned above, and therefore, the flame downstream of the ejection hole 00 is continuously ignited by this flame, and the burner as a whole also The flame is kept stable at all times.

That is, according to the present invention, the combustion load range is extremely wide.
A premixed gas burner is obtained.

In the above explanation, the protrusions (
In c), the pin-shaped one has an oblate spherical head, but in this invention, the invention is not limited to the one in the above embodiment.
For example, as shown in FIGS. 4(a) to (c), it may have a disc-shaped head (21') or a conical head (21"). Furthermore, it may be cylindrical and have no distinction between the neck and the head.

Furthermore, the protrusion 12G is not limited to the substantially pin-shaped one described above, but may also include a bar-shaped protrusion (20') with a T-shaped cross section, or a wedge-shaped protrusion (20') as shown in FIGS. Protrusion (20”
) etc.

The number and arrangement of the protrusions Ql) provided on the flame stabilizer 00) may be determined in accordance with various conditions such as the combustion load and the fuel used. Deploy.

Further, in the above explanation, the flame stabilizer 00) is a ceramic flat member having a large number of premixture jet holes 01), but the flame stabilizer to which this invention is applied is as shown in FIG. Each window hole in the two perforated boards (as shown in Figure 1)
A heat-resistant spherical member (32) is fitted into the ribbon, and a flat and corrugated ribbon (40) (41) as shown in Figure 6.
It is also possible to use a porous block in which ribbons (42) formed with inclined waveforms as shown in Fig. 7 are stacked so that the inclination directions intersect with each other. The shape is not limited to the shape, but it can also be a curved or cylindrical shape.

〔Effect of the invention〕

As explained above, according to the flame stabilizing temporary for a premixed gas burner according to the present invention, the supply pressure of the premixed gas is high, and even in areas where the flame lifts or blows out in conventional gas burners, the protrusion The small flames formed on the back surface promote continuous ignition of the premixture, making it possible to effectively hold the flame over the entire combustion surface. Therefore, compared to conventional burners, the range of combustion loads in which stable combustion can be achieved is expanded, and an extremely practical premix burner can be provided.

Furthermore, the combustion load can be increased compared to conventional ones (those with the same amount of fuel), and significant downsizing can be achieved.

[Brief explanation of drawings]

1 to 3 show an embodiment of a flame stabilizer for a premixed gas burner according to the present invention. FIG. 1 is an overall perspective view, and FIG. Front view, Figure 3 (a),
(b) is a schematic sectional view for explaining the combustion situation in the present invention. FIGS. 4(a) to 4(e) are perspective views showing other examples of the protrusion shape of the flame stabilizer for a premixed gas burner according to the present invention. FIGS. 5 to 7 are overall perspective views showing other embodiments of the flame stabilizer for a premixed gas burner according to the present invention. FIGS. 8 and 9 show an example of a conventional premixing gas burner, with FIG. 8 being a front view and FIG. 9 being a longitudinal sectional view of a main part.

Claims (1)

[Claims] (1) In a device in which a premixture is ejected from a large number of nozzles (11) provided in a flame stabilizer (10), and a combustion flame is formed on the surface of the flame stabilizer, a large number of protrusions ( 20) A flame stabilizer for a premixed gas burner characterized by being dotted with.