JP3153444B2 - Method of manufacturing a combustion plate for a surface combustion burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a combustion plate for a surface combustion burner used in various combustion devices such as a water heater.

[0002]

2. Description of the Related Art Conventionally, as a surface combustion burner used for various combustion devices such as a water heater, a combustion plate is attached so as to cover one surface of a gas burner main body, and gas ejected from the combustion plate is used for the combustion plate. There is known a configuration in which combustion occurs on the surface of an object.

In recent years, it has been studied to use a compact obtained by laminating silicon carbide-coated Si—CO—based silicon carbide fibers on the combustion plate. As the silicon carbide fibers, SiC _1.20 O _0.42 SiC-O type silicon carbide fiber having a composition of (Nippon Carbon Co., Ltd., Nicalon (trademark)) is known. This fiber is a flexible continuous filament yarn which is susceptible to pyrolysis itself, but which can be chemically vapor deposited (abbreviated as CVD) or chemical vapor infiltration (Chemical VaporInf).
illumination, abbreviated as CVI method)
By coating the surface with silicon carbide, excellent heat resistance suitable for the combustion plate can be obtained.

Si—C coated with silicon carbide
When a molded body obtained by laminating -O-based silicon carbide fibers is used for the combustion plate, gas is ejected from gaps between the fibers, so that the entire surface of the combustion plate can be a combustion surface. Depending on the porosity of the fibers in (1), it is desirable to further provide a flame port that penetrates the combustion plate so that gas is mainly ejected from the flame port and burned.

[0005] However, when the perforated member is penetrated through a formed body obtained by laminating the Si-CO-based silicon carbide fibers coated with silicon carbide on the fiber surface to form the flame port, the perforated member is formed. Depending on the penetrating direction from which side of the molded body penetrates, after removing the perforated member, the fiber swells from the outer peripheral side of the flame port where the fiber is formed into the flame port and has a desired diameter. There is an inconvenience that it is difficult to form a flame outlet.

[0006] Further, when the perforated member is made to penetrate a formed body obtained by laminating the Si-CO-based silicon carbide fibers coated with silicon carbide on the fiber surface to form the flame port, the perforated member is formed. Depending on the penetrating direction, when the perforated member collides with the surface of the molded body, the silicon carbide fibers are scattered, or the formed flame hole is deformed and a flame hole having a desired shape is hardly formed. There is an inconvenience.
Further, in the portion where the flame outlet is densely arranged, by the impact when the piercing member collides with the surface of the molded body,
There is a disadvantage that the molded body may be broken.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages and to provide a Si-CO-coated silicon carbide coated silicon carbide.
It is an object of the present invention to provide a manufacturing method capable of easily manufacturing a combustion plate having a flame port having excellent shape and dimensional accuracy from a molded body obtained by laminating a series of silicon carbide fibers.

[0008]

When a compact formed by laminating Si-CO-based silicon carbide fibers is coated with silicon carbide (SiC) by a CVD method or a CVI method, for example, it is heated to about 1200 to 1300 ° C. 20 heated
By horizontally disposing the compact in a low-pressure furnace of about ~ 60 Torr and flowing down a carrier gas flow containing a raw material gas for reaction such as SiCl ₄ and CH ₄ from above the compact vertically, Si on the surface of the fiber forming the compact
C is deposited to form a SiC coating. According to the study of the present inventors, a formed body having a predetermined thickness obtained by laminating the Si-CO-based silicon carbide fibers by the CVD method or the CVI method is entirely coated in the thickness direction. When coated with SiC over the surface, the reaction raw material gas increases toward the lower side under the influence of gravity, and the thickness of the SiC coating is thin on the surface of the molded body facing the air flow, and the thickness of the SiC coating is small on the opposite surface. It was found that the thickness of the SiC coating was increased.

As a result of further studies based on the above findings, the present inventors have found that Si—C coated Si—C
In the -O-based silicon carbide fiber, the hardness increases as the thickness of the SiC coating increases, but from a surface having a low hardness to a surface having a high hardness,
It has been found that by penetrating the perforated member, the fiber does not swell from the outer peripheral side of the flame port into which the fiber is formed after the perforated member is removed.

Therefore, a method of manufacturing a combustion plate for a surface combustion burner according to the present invention is a method of manufacturing a combustion plate attached to cover one surface of a gas burner main body of a surface combustion burner. Forming a formed body having a predetermined shape by laminating O-based silicon carbide fibers; and forming the formed body in a high-temperature, low-pressure state, facing a gas stream containing a raw material gas for reaction to form silicon carbide on the fiber surface. A coating step of coating the fiber surface with a silicon carbide film by depositing, and forming the molded body obtained in the coating step from the side facing the gas flow containing the reaction raw material gas during the coating. A flame port forming step of forming a flame port penetrating the perforated member toward the opposite surface to form a flame port penetrating the molded body.

Further, in the method for manufacturing a combustion plate for a surface combustion burner according to the present invention, in the flame port forming step, the side of the molded body obtained in the coating step on the side opposed to the gas flow containing the reaction raw material gas. Abuts a first plate member having a plurality of holes for guiding the perforated member on a surface,
A second plate member having a plurality of holes for accommodating the perforated member is brought into contact with the surface on the opposite side of the molded body, and the perforations are formed from the holes of the first plate member to the holes of the second plate member. The flame port is formed by penetrating a member. A suppressing member for suppressing the compression deformation of the molded body is interposed between the two plate members.

[0012]

According to the production method of the present invention, a molded body obtained by laminating Si-CO-based silicon carbide fibers is opposed to an air flow containing a raw material gas for reaction at a high temperature and a low pressure. When the surface is coated with silicon carbide, the raw material gas for reaction increases under the influence of gravity, so that the thickness of the silicon carbide film is reduced on the surface of the molded body facing the airflow, On the side surface, the thickness of the silicon carbide film increases.

[0013] As described above, the Si-CO-based silicon carbide fiber whose surface is coated with silicon carbide tends to harden and increase rigidity as the thickness of the silicon carbide film increases, In this case, by piercing the piercing member from the surface facing the airflow containing the reaction raw material gas toward the opposite surface, when the piercing member is pulled out, the flame port in which the fibers are formed The fiber does not swell from the outer peripheral side into the flame port, and the scattering of the fibers and the collapse of the formed flame port are reduced.

Further, as described above, Si-CO-based silicon carbide fibers having a fiber surface coated with silicon carbide tend to harden and become brittle as described above. According to the present invention, a first plate member having a plurality of holes for guiding the perforated member and a second plate having a plurality of holes for accommodating the perforated member are provided on both front and back surfaces of the molded product obtained in the coating step. Since the plate member is in contact with the plate member, the formed body on which the embrittled silicon carbide fibers are laminated is reinforced, and the punched member does not break even if it collides.

Further, when the two plate members are used, a suppressing member for suppressing the compression deformation of the molded body is interposed between the two plate members, so that in the flame port forming step,
The compact is not excessively compressed.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a method of manufacturing a combustion plate for a surface combustion burner according to the present invention. FIG. 1 is a perspective view showing a configuration example of a surface combustion burner using the combustion plate of the present invention, FIG. 2 is an end view taken along line II-II of FIG. 1, and FIG. 3 is an explanatory cross section showing a method of coating silicon carbide. FIGS. 4, 5 and 6 are explanatory sectional views showing one embodiment of the method for manufacturing a combustion plate of the present invention. FIG. 6 is an explanatory sectional view showing another embodiment of the method for manufacturing a combustion plate of the present invention. FIG. 7 is an explanatory sectional view showing the tip shape of the perforating member.

The surface-burning burner of this embodiment is used in a rear-exhaust-type combustion apparatus for cooking grilled fish such as grilled fish, which is generally called a grill. The upper burner is disposed so as to face the material to be burned. As shown in FIG. 1, a surface combustion burner 1 is a flat box-shaped gas burner main body including a gas mixing pipe 2 for mixing a gas ejected from a nozzle (not shown) and primary air to supply a gas mixture. 3 coated with silicon carbide to cover one surface of Si-C-
A combustion plate 4 formed by laminating O-based silicon carbide fibers is attached such that the surface facing the airflow containing the reaction source gas is a combustion surface during the coating. In the surface combustion burner 1, as shown in FIG. 2, a gap between the gas burner main body 3 and the combustion plate 4 forms a gas passage 5 for flowing a gas mixture supplied from a gas mixing pipe 2. The combustion plate 4 is provided with a large number of small-diameter flame ports 6 that penetrate the combustion plate 4 to eject and burn the gas mixture.

The diameter of the flame outlet 6 is 0.8 to 0.8 depending on the gas type.
It is appropriately selected within a range of up to 1.2 mm. In the combustion plate 4 of the present embodiment, the main combustion flame is mainly formed by the combustion of the gas mixture ejected from the flame port 6, and the gas ejected from the gap of the fiber also in the portion where the flame port 6 is not provided. A small flame is formed by the secondary combustion of the air-fuel mixture.

Next, an embodiment of a method of manufacturing the combustion plate 4 will be described.

In this embodiment, first, the diameter is 9 to 25 μm,
Si—C—O based silicon carbide fibers having a density of 2.0 to 3.0 g / cm ³ are mixed with water or starch paste, a ceramic adhesive,
Synthetic resin adhesive [for example, polyvinyl alcohol (PV
A)] and the like, dispersed in a mold having a predetermined shape, laminated and formed (papermaking method), pressed, dried when using water, and dried when using a binder solution. The binder is incinerated and removed at a temperature at which the silicon carbide fiber does not thermally degrade, and has a thickness of 1.5 to 6.0 mm.
Molded article.

Next, the compact is coated with silicon carbide by the CVD method to form a SiC coating on the surface of the fiber. In the CVD method, as shown in FIG. 3, a molded body 7 obtained by laminating Si—CO—based silicon carbide fibers is horizontally arranged in a CVD furnace under a high temperature and a low pressure. This is performed by flowing down a gas stream 8 of a carrier gas (H ₂ ) containing reaction source gases (SiCl ₄ and CH ₄ ) from vertically above. The CVD furnace is heated to a temperature in the range of 1200-1300 ° C. and depressurized to a pressure in the range of 20-60 Torr. When the treatment is performed under the high-temperature and low-pressure conditions for 5 to 30 minutes, the surface of the Si—C—O-based silicon carbide fiber is 0.1 to 0.7 μm on the surface 7 a of the molded body 7 facing the airflow 8. Of SiC film. Also, on the opposite surface 7b, the amount of the raw material gas for reaction increases under the influence of gravity,
The surface of the fiber is coated with a thicker SiC coating than surface 7a.

Both surfaces of the molded body 7 are formed Si
As described above, the C coating is formed on the surface 7a on the side opposite to the airflow 8 on the surface 7b on the side opposite to the airflow 8.
And the surface 7b also has a higher hardness. Therefore, as shown in FIGS. 4 and 5, a perforated member is formed from the surface of the molded body 7 facing the airflow 8 and having the relatively low hardness and the soft surface 7 a to the opposite surface 7 b. 9 is made to penetrate, so that the flame port 6 is formed to be the combustion plate 4.

In this embodiment, as shown in FIG. 4, a punch 9 provided in a punching device 11 is used as the piercing member 9. The punching device 11 includes an upper member 13 provided to be able to move up and down by a cylinder 12, and a plate-like lower member 14 on which the molded body 7 is placed. Upper member 13
A plate-like stripper 1 having a plurality of punches 9 standing vertically downward and having holes 15 for guiding the punches 9 when the punches 9 punch the molded body 7.
6 is attached via a rod 17 so as to be able to move up and down. The lower member 14 is provided with a die 18 for accommodating the punch 9 when the punch 9 is lowered by the cylinder 12, and is provided at both sides of the molded body 7 to be placed. A block 19 is provided to prevent the 7 from being excessively compressed between the stripper 16 and the lower member 14. The molded body 7 is located on the side of the surface 7b,
4.

According to the punching device 11, as shown in phantom lines in FIG.
Is lowered, the stripper 16 first contacts the surface 7a of the molded body 7, and in this state, the molded body 7 is in contact with the stripper 16 on the surface 7a and the lower member 14 on the surface 7b.

Next, as shown in FIG. 5 (a), when the upper member 13 is further lowered by the cylinder 12, the stripper 16 slightly compresses the molded body 7 to form the block 19.
, And the punch 9 is inserted into the hole 1 of the stripper 16.
5, penetrates from the surface 7 a of the molded body 7 toward the surface 7 b, and the tip of the penetrated punch 9 is accommodated in the die 18 of the lower member 14. At this time, the compact 7 is compressed between the stripper 16 and the lower member 14, but the block 19 is interposed between the stripper 16 and the lower member 14. When the stripper 16 is raised by the cylinder 12 and is not compressed, and the compression is released, the original shape can be restored.

Next, the cylinder 12 is raised and the punch 9 is removed from the compact 7 to obtain the combustion plate 4 having the flame port 6 as shown in FIG. 5B.

Next, using the apparatus shown in FIGS. 4 and 5,
When the punch 9 is penetrated from the side of the surface 7a of the molded body 7 toward the surface 7b (Example 1),
The diameter and shape of the formed flame port 6 were compared between when the punch 9 was penetrated toward (Comparative Example 1).

Here, the punching device 11 includes 46 flat-headed punches 9 having a diameter of 1.21 mm on the upper member 13 having a rectangular shape in a plan view, and 46 at 3.5 mm intervals in the long side direction of the rectangular shape, and the short side direction. In this example, thirteen pieces are provided at 3.15 mm intervals, that is, 598 pieces in total. The lower member 14 is provided with the same number of holes 18 having a diameter of 1.3 mm to accommodate the punches 9. The molded body 7 has a thickness of 3.2 mm, and the block 16 has a thickness of 2.5 mm.
mm. Flames 6 formed in each case
, Four points adjacent to each other and forming a square were arbitrarily selected, and the diameter was measured. It is shown in Table 1 below.

[0029]

[Table 1] As is clear from the results in Table 1, in Example 1, the diameter of the formed flame port 6 was substantially equal to the diameter of the punch 9 used, and there was no variation. The diameter is smaller than the diameter of No. 9 and variation is observed. At the same time, when the shape of the four nozzles 6 was visually observed, the shape of the nozzle 6 was small in Example 1 but the shape of the nozzle 6 was severe in Comparative Example 1.
Fibers protruding into the flame port 6 from the outer peripheral side were observed.

In the first embodiment, the fiber of the molded body 7 is punched out at the portion where the tip of the piercing member 9 abuts, and the fiber around the piercing member 9 is formed by a flame port formed when the piercing member penetrates. It is pushed away in the outer peripheral direction,
Since the perforated member 9 is made to penetrate from the side of the relatively soft surface 7a to the opposite surface 7b, the fiber which has been pushed out once has the flame port 6 formed even after the perforated member 9 is removed. It is conceivable that the flame port 6 is not swelled from the outer peripheral side into the flame port 6 and is substantially equal to the diameter of the punch 9 as described above and has no variation.

On the other hand, in Comparative Example 1, the piercing member 9 is made to penetrate from the relatively hard surface 7b of the molded body 7 to the opposite surface 7a. It is considered that the fiber once pushed out swells into the flame port 6 from the outer peripheral side of the flame port 6 formed by its rigidity, and narrows the diameter of the flame port 6. Further, it is considered that the protrusion of the fibers is such that when the punch 9 is removed, a part of the fibers swelling into the flame opening 6 further jumps out due to its rigidity.

Next, another embodiment of the method of manufacturing the combustion plate 4 will be described.

In this embodiment, as shown in FIG. 6, except that the block 19 interposed between the stripper 16 and the lower member 14 is not provided, the punching device 11 is exactly the same as the punching device 11 shown in FIG. The combustion plate 4 is manufactured using the punching device 11.

In the apparatus shown in FIG. 6, when the upper member 13 is lowered by the cylinder 12, the stripper 16 first
When the upper member 13 is further lowered by the cylinder 12 because the block 19 to be interposed between the stripper 16 and the lower member 14 is not provided, the stripper 16 and the lower member While the compact 7 is compressed between the stripper 16 and the stripper 16.
Of the molded body 7 from the side of the surface 7a
The tip of the punch 9 that penetrates toward “b” is accommodated in the die 18 of the lower member 14. Next, the cylinder 12 is raised, and the punch 9 is removed from the molded body 7 to obtain the combustion plate 4 in which the flame port 6 is formed.

Next, using the apparatus shown in FIG. 6, the punch 9 is made to penetrate from the surface 7a of the molded body 7 to the surface 7b (Example 2). Toward
The diameter and shape of the formed flame port 6 were compared between when the punch 9 was penetrated (Comparative Example 2).

Here, the configurations of the punch 9 and the die 18 are as follows.
This is the same as in the case of Example 1 and Comparative Example 1. Nine points adjacent to each other and forming a square were arbitrarily selected from the flame holes 6 formed in each case, and the diameters were measured. It is shown in Table 2 below.

[0037]

[Table 2] In the second embodiment, since the block 19 is not provided,
The compact 7 is compressed and the initial thickness of 2.5 mm is
Is formed, it is slightly reduced to 2.2 mm. For this reason, the diameter of the formed flame port 6 is slightly smaller than that of the first embodiment, but the perforated member 9 is made to penetrate from the relatively soft surface 7a of the molded body 7 to the opposite surface 7b. As shown in Table 2, the diameter of the punch 9 (1.2 m
m) has a practically sufficient diameter close to m), and has a small variation.

On the other hand, in Comparative Example 2, since the piercing member 9 is penetrated from the relatively hard surface 7b of the molded body 7 to the opposite surface 7a, the compression of the molded body 7 is prevented. The amount of fibers swelling into the flame outlet 6 from the outer peripheral side of the flame outlet 6 formed by the above becomes further larger, the average diameter of the flame outlet 6 is smaller than the average diameter of the second embodiment, and the variation is larger than that of the second embodiment. Has become. At the same time, when the shape of the four nozzles 6 was visually observed, the shape of the nozzle 6 was small in Example 2, but the shape of the nozzle 6 was severe in Comparative Example 2. Fibers protruding from the side into the flame outlet 6 were observed.

In each of the above embodiments, the molded body 7 is sandwiched between the stripper 16 and the lower member 14,
Since the piercing member 9 is penetrated, the flame port 6
, But the molded body 7 did not break.

In each of the above embodiments, the punch 9 is
As shown in FIG. 7A, a flat-head type having a flat end 21 is used, but FIGS. 7B to 7D are used.
The punch 9 having another tip shape as shown in FIG. The punch 9 shown in FIG. 7 (b) has a flat surface 21 at the tip and a tapered portion 22 provided on the periphery. The punch 9 shown in FIG. 7C has a tip 23 which is a convex surface 23. Further, the punch 9 shown in FIG. 7D is provided with a projection 24 having a flat end at the center in the center. In addition, the piercing member 9
Alternatively, a drill (not shown) provided on a drilling machine may be used instead of the punch 9.

Further, in each of the above embodiments, the coating of the molded body 7 is performed by the CVD method, but may be performed by the CVI method. Further, in each of the above embodiments,
Although the surface combustion burner used in the rear exhaust combustion device for cooking porcelain is described, the surface combustion burner of the present invention is not limited to this, and can be used in various combustion devices such as a water heater. .

[0042]

As is evident from the above, according to the manufacturing method of the present invention, silicon carbide coated S
From a molded body obtained by laminating i-C-O-based silicon carbide fibers, a combustion plate having a flame port with excellent shape and dimensional accuracy can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one configuration example of a surface combustion burner using a combustion plate of the present invention.

FIG. 2 is an end view taken along line II-II of FIG.

FIG. 3 is an explanatory sectional view showing a method for coating silicon carbide.

FIG. 4 is an explanatory sectional view showing one embodiment of the method for manufacturing a combustion plate of the present invention.

FIG. 5 is an explanatory sectional view showing one embodiment of a method for manufacturing a combustion plate according to the present invention.

FIG. 6 is an explanatory sectional view showing another embodiment of the method for manufacturing a combustion plate according to the present invention.

FIG. 7 is an explanatory sectional view showing a tip shape of a perforated member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Surface combustion burner, 3 ... Gas burner main body, 4 ... Combustion plate, 6 ... Flame port, 7 molded body, 7a ... Surface facing the airflow containing reaction raw material gas, 7b ... Contains reaction raw material gas The surface on the opposite side of the side facing the airflow,
8 ... gas stream containing raw material gas for reaction 9 ... perforated member 1
4 ... first plate member, 16 ... first plate member, 19 ... suppression member.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F23D 14/12-14/18

Claims (3)

(57) [Claims] 1. A method for manufacturing a combustion plate attached so as to cover one surface of a gas burner main body of a surface combustion burner, comprising forming a predetermined shape by laminating Si—CO—based silicon carbide fibers. Forming a molded body for forming a body; and coating the fiber surface with a silicon carbide coating by depositing silicon carbide on the fiber surface by facing the molded body under a high temperature and a low pressure to an air current containing a raw material gas for reaction. In the coating step, the molded body obtained in the coating step is caused to penetrate a perforated member from the surface facing the airflow containing the reaction raw material gas toward the opposite surface during the coating, A method for producing a combustion plate for a surface combustion burner, comprising: a flame port forming step of forming a flame port penetrating a molded article. 2. In the flame port forming step, a plurality of holes for guiding the piercing member are provided on a surface of the molded body obtained in the coating step on a side facing the airflow containing the raw material gas for reaction. The first plate member is brought into contact with the second plate member having a plurality of holes for accommodating the perforated member on the surface on the opposite side of the molded body, and the second plate member is brought into contact with the second plate member from the hole of the first plate member. The method for manufacturing a combustion plate for a surface combustion burner according to claim 1, wherein the flame port is formed by passing the perforated member through a hole of the second plate member. 3. The method for manufacturing a combustion plate for a surface combustion burner according to claim 2, wherein a suppressing member for suppressing a compressive deformation of the compact is interposed between the two plate members.