JPS6256404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a burner device suitable for combustion of a mixture of powdered solid fuel such as coal and liquid fuel such as petroleum.

In the conventional burner device of this kind, as shown in FIGS. 1 to 3, a steel spray plate 01 and a back plate 02 are mounted on a seat 03 with a cap nut 0
It is pressed and fixed at 4. The spray plate 01 is provided with a fuel passage 05, a pressure medium passage 06, and a mixing passage 07, and a pressure medium 010 consisting of fuel 09 and pressurized steam or air is mixed in the mixing passage 07. and is sprayed into the furnace from the spray hole 08. When such a burner device is used to burn fuel consisting of a mixture of powdered solid fuel and liquid fuel, the stepped constriction portion 0 of the fuel flow path 05
11 and the mixing flow path 07, and there is a problem that the spray plate 01 must be replaced in a short period of time. Furthermore, as shown in Fig. 3, the fuel flow path 0
5 and the inner surface of the mixing channel 07 are made of ceramic material 012.
Coating with ceramic material or embedding ceramic tubes have been proposed, but these have the following drawbacks. That is, spray plate 01
Since it is a steel material, it has a larger coefficient of thermal expansion than the ceramic material 012, and the flow paths 05 and 07 through which the fuel passes.
A gap is created between the steel material 012 and the ceramic material 012, which causes problems such as misalignment of the fuel injection direction and the application of tensile stress to the inner surface of the ceramic material 012, which tends to cause cracks.

For this reason, it is necessary to replace the spray plate 01 within a short period of time, and the problem of increasing maintenance costs cannot be avoided.

An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional devices and provide a burner device that has good combustion efficiency and can withstand long-term use. In the burner device, the spray plate is provided with a plurality of mixing channels that are open at intervals in the circumferential direction of the front end surface of the spray plate, and a plurality of fuel channels that are respectively connected to the mixing channels. The burner device is made of ceramic material and has a cover fixed to the entire outer surface of the spray plate on the furnace side.

According to the present invention, since the spray plate is made of ceramic material, the wear resistance is greatly improved, and since the entire outer surface of the spray plate on the furnace side is covered by the cover, the ceramic material is If the spray plate is protected from seizure due to the high temperature inside the furnace, and if the spray plate is made only of ceramic material, oil droplets will adhere to the outer surface of the spray plate on the furnace side and solidify. If the oil remains on the ceramic material for a long period of time, the oil will penetrate inside and make the ceramic material brittle. To prevent this, it is necessary to remove the solidified oil from the outer surface. When removing, be careful not to damage the surface of the ceramic material, as if the surface of the ceramic material is scratched, cracks will occur from the scratched area due to high heat, etc.
This requires great care and maintenance is difficult, but by fixing the cover to the ceramic material, the oil adheres to the cover and solidifies, preventing it from directly adhering to the ceramic material. The spray plate can be removed by scraping off the oil, making maintenance easy, and furthermore, by replacing only the cover, the spray plate can be used for a long period of time.

An example in which the present invention is applied to a burner device for burning a mixed fuel of powdered solid fuel such as coal and liquid fuel such as petroleum will be described below with reference to FIGS. 4 to 6.

1 is a spray plate, which is entirely made of ceramic material. 2 is the back plate, 3 is the seat,
4 is a cap nut, 11 is a cover, and cover 1
1, spray plate 1, and back plate 2
is pressed and fixed to the seat 3 by a cap nut 4. The spray plate 1 is provided with a fuel flow path 5, a pressure medium flow path 6, and a mixing flow path 7.
Fuel 9 and pressure medium 10 are led through seat 3 and back plate 2 to fuel channel 5 and pressure medium channel 6, respectively. The cover 11 is fitted so as to cover the outer surface of the spray plate 1 on the furnace side, and the convex portion 13 is connected to the concave portion 12 of the spray plate 1.
is engaged in.

Also, near the mist nozzle 8, the cover 11 has a thin portion 11.
B and a slope 11C are provided, and in a place away from the mist nozzle 8, the cover 11 has thick parts 11D, 11A, 1
1E and 11F are provided.

In addition, 12 recessed holes are provided in the spray plate 1,
Instead of fitting with the convex portion 13 of the cover 11, the seventh
As shown in the figure, a concave groove 14 extending along the axial direction may be provided on the outer circumference of the spray plate 1, and a convex portion that engages with the concave groove 14 may also be provided on the cover 11.

In the burner device as described above, the fuel 9, which is a mixture of powdered solid fuel and liquid fuel, passes through the fuel flow path 5, mixes with the pressure medium 10 in the mixing flow path 7, and is sprayed into the furnace (not shown). It is sprayed from hole 8 and burns.

According to such a burner device, the following effects can be obtained.

(a) Abrasion resistance is improved by using ceramic material for the spray plate 1. Mohs hardness is iron
4.5, and the alumina base ceramic has a rating of 9.0, so wear resistance is greatly improved.

(a) By making the entire spray plate 1 of ceramic material, the strength of the fuel flow path 5 and the mixing flow path 7 can be maintained.

(If only the inner surfaces of both channels 5 and 7 are made of ceramic material and the spray plate 1 is made of steel,
Due to the difference in thermal expansion, large tensile stresses act on the inside of the ceramic channel. By the way, even though ceramic materials have excellent compressive strength, their tensile strength is low, and the tensile strength/compressive strength = about 1/10, which is less than 1/4 of cast iron. This means that ceramic materials are susceptible to brittle fracture. Therefore, if only the flow path is made of ceramic material, the percentage of cracks occurring will increase.

Furthermore, if only the flow path through which the fuel passes is made of ceramic material, there is a risk that the direction of fuel injection may change due to the difference in thermal expansion between the ceramic material and the steel material of the spray plate 1, such as displacement of the ceramic material. ) (C) Cover the ceramic spray plate 1 and
By covering the cap nut 4 with a cap nut 4, when the cap nut 4 is tightened to the seat 3, it can be prevented from being broken by a small external force due to stress concentration.

(Ceramic materials break due to manual stress, so the maximum tensile stress that occurs must be kept below the tensile strength of the ceramic material.

Furthermore, since ceramic material is inferior in impact strength to steel material, cover 11 is effective in protecting spray plate 1 when handling a burner gun. ) (d) Cover the ceramic spray plate 11
By covering the ceramic material with fuel, you can protect it from seizure and further extend its service life. (Ceramic materials soften as the surface temperature rises,
As a result, seizure occurs and the surface film is destroyed. ) (E) Several recesses 12 on the outer surface of the spray plate 1.
By providing a convex portion 13 on the spray plate cover 11 and matching the two, it is possible to prevent rotational deviation between the two.

(F) By etching the fuel flow path 5 and the mixing flow path 7, the strength can be increased and at the same time, the flow of fuel becomes smooth.

(g) Since the cover 11 is removable, the spray plate 1 can be used for a long period of time by replacing only the cover 11.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional device, FIG. 2 is a view taken along the - arrow in FIG. 1, FIG. 3 is a partial sectional view showing another example of the conventional device, and FIG. The plan view shown in Fig. 5 is the - arrow view of Fig. 4, and Fig. 6
The figure is a perspective view of the spray plate according to the present invention, and FIG. 7 is a perspective view showing another example of the spray plate according to the present invention. 1...Spray plate, 2...Back plate, 3
... Seat, 4... Cap nut, 5... Fuel flow path, 6...
Pressure medium channel, 7...mixing channel, 11...cover.

Claims (1)

[Claims] 1. A spray plate and a seat are connected by a cap nut, and a plurality of mixing channels are opened at intervals in the circumferential direction of the front end surface of the spray plate, and a plurality of fuels are respectively connected to the mixing channels. 1. A burner device comprising a flow path, characterized in that the spray plate is made of ceramic material and a cover is fixed to the entire outer surface of the spray plate on the furnace side.