BURNER UNIT FOR FIRING FURNACE

Abstract: A burner unit is used for firing, for example, formed ceramic bodies in a firing furnace. The burner unit includes a burner tile assembly (3) provided in a furnace wall and a burner (2) connected to the burner tile assembly and extending out of the firing furnace. The burner is integrally provided with a connecting burner tile assembly (6) having a taper (6a). The burner tile assembly (3) is also provided with a taper (3a). The tapers of the connecting burner tile assembly and the burner tile assembly mate and a sealing material (8) connects the burner to the burner tile assembly. With this arrangement, the burner unit reduces heat dissipation due to a burner construction and enables maintenance to be effected during operation of the burner.

Description: This invention relates to a burner unit for a firing furnace including a burner tile assembly provided in the furnace wall and a burner connected to the burner tile assembly and extending out of the firing furnace. Such a furnace is used for firing, for example, formed ceramic bodies. A burner as described above is illustrated in US-A-3843317. A similar known burner is shown in a sectional and a side view of Figs. 1a and 1b, and is known for using natural gases or the like as a fuel for firing formed ceramic bodies in a firing furnace. As shown in Figs. 1a and 1b, in a furnace wall 21 made of a refractory material there is provided a burner tile assembly 22 and a burner 25 is bolted to the burner tile assembly 22 through a burner holder 24 and a front plate 23 provided on an outer surface of the burner tile assembly 22. With such a burner unit, however, high temperature gases in the furnace tend to leak out of the surface through connections between the burner tile assembly 22 and the furnace wall 21 and cracks in the wall and tiles. Therefore, the front plate 23 is often heated by the leaked high temperature gases to a red-hot state so that the heat in the furnace is dissipated uselessly. Moreover, since the burner unit is fixed by bolts to the burner tile assembly 22 through the red-hot front plate 23, such a heated plate makes difficult maintenance of the furnace such as filling with ceramic fibers during operation of the burner 25′. It is an object of the invention to provide a burner unit for a firing furnace, which can eliminate the disadvantages of the prior art and which reduces dissipation of heat in the furnace as much as possible and enables maintenance of the furnace to be effected during operation of the burner unit. The invention is set out in claim 1. With the above construction, the burner and the burner tile assembly in the furnace wall are connected with each other by means of a connecting burner tile assembly made of e.g. one or more refractory bricks integral with the burner without using any front plate made of a metal. In connecting them, moreover, the tapers adapted to be fitted with each other are provided at connecting surfaces of the burner tile assembly and connecting burner tile assembly. Therefore, any leakage of gases in the furnace can be reduced and heating to red-heat which would otherwise occur at the front plate is prevented. In the invention, preferably a seal material such as ceramic fibers is interposed between the connecting surfaces of the burner tile assembly and the connecting burner tile assembly. Since there is no heating to red-heat in the burner unit according to the invention, the ceramic fibers as the sealing material can be replaced and retaining bolts for the connecting burner tile assembly can be tightened if they are inadvertently loosened in operation of the burner unit. The invention will be more fully understood by referring to the following detailed description of an embodiment given in connection with the appended drawings. Fig. 1a is a partial sectional view illustrating one example of a burner unit for a firing furnace of the prior art; Fig. 1b is a side view of the burner shown in Fig. 1a; Fig. 2a is a partial sectional view illustrating one embodiment of the burner unit according to the invention; and Fig. 2b is a side view of the burner unit shown in Fig. 2a. In the embodiment of the invention, a burner tile assembly 3 is provided in a furnace wall of the firing furnace for leading burnt gases from the burner 2, and a space 4 is provided inside the burner tile assembly in the furnace. A Venturi tile assembly 5 is arranged in the space 4. A connecting burner tile assembly 6 made of a refractory body integrally formed with the burner 2 is provided on an outer side of the burner tile assembly 3 and fixed thereto by retaining bolts 7-1 to 7-4. Sealing materials 8 made of ceramic fibers or the like are provided at contacting surfaces between the burner tile assembly 3 and the connecting burner tile assembly 6, while the contacting surfaces between the tile assemblies are connected by providing tapered steps 3a and 6a on the connecting surfaces adapted to be fitted with each other. Moreover, the burner 2 is arranged on a burner support 9. Furthermore, the burner unit is displaced toward the inside of the furnace by a distance corresponding to a thickness of the connecting burner tile assembly 6 by a bridge brick assembly 10 to provide a space 11 in the furnace wall 1. The furnace wall 1 is formed above the burner tile assembly 3 with an aperture 12 for introducing a thermocouple for detecting temperatures in the furnace. With the burner unit constructed as above described, any leakage of gases through connecting portions between the burner tile assembly 3 and furnace wall 1 is minimised by providing the tapered steps 3a and 6a on the connecting surface therebetween. Moreover, by making the connecting burner tile assembly 6 from a refractory body such as refractory bricks made of alumina or the like in conjunction with the prevention of leakage of high temperature gases in the furnace, heating to red-heat is completely prevented so that useless heat dissipation resulting from the leakage of high temperature gases and hence the heating to red-heat can be eliminated. In this embodiment, the connecting burner tile assembly 6 is fixed to the burner tile assembly 3 by means of retaining bolts 7-1 to 7-4. Therefore, for example, the sealing materials 8 made of ceramic fibers or the like can be replaced during operation of the burner 2 and the retaining bolts 7-1 to 7-4 for the connecting burner tile assembly 6 can be tightened if they become inadvertently loosened, without stopping the operation of the burner unit. In the embodiment shown in Figs. 2a and 2b, configurations of the tapered steps 3a and 6a and the connecting burner tile assembly 6 and positions and numbers of the retaining bolts 7-1 to 7-4 may of course be changed. As can be seen from the above explanation, according to the invention, the predetermined connecting burner tile assembly is provided between the burner tile assembly in the furnace wall and the burner and is fixed to the burner tile assembly in the furnace wall. The burner unit according to the invention reduces heat dissipation due to a burner construction and enables maintenance to be affected during operation of the burner.

Claims: A burner unit for a firing furnace including a burner tile assembly (3) provided in a furnace wall and a burner (2) connected to the burner tile assembly and extending out of the firing furnace; characterized in that said burner unit is integrally provided with a connecting burner tile assembly (6) having a taper (6a), and said burner tile assembly (3) has a corresponding taper (3a), and said tapers (3a,6a) of the connecting burner tile assembly and said burner tile assembly mate, and there being a sealing material (8) between the burner (2) and the burner tile assembly (3). A burner unit for a firing furnace as set forth in claim 1, wherein a space (4) is provided at the inside of the burner tile assembly (3) and a Venturi tile assembly (5) is provided in the space (4). A burner unit for a firing furnace as set forth in claim 1 or claim 2, wherein said burner unit (2) is displaced toward the inside of the furnace by a distance corresponding to a thickness of the connecting burner tile assembly (6) to provide a space (11) in the furnace wall. A burner unit for a firing furnace according to any one of claims 1 to 3 wherein the sealing material (8) is of ceramic fibers. A burner unit for a firing furnace according to any one of the preceding claims, wherein the connecting burner tile assembly (6) is a refractory body integrally formed with the burner (2).

Inventors: MIYAHARA, KAZUHIRO, MIYAJIMA, TOYOSHIRO
Applicants: NGK INSULATORS, LTD.
Application year: 1989
Main classification: F23C5
IPC codes: F23M5, F23C5