Burner tile assembly

Abstract: A high-speed type burner tile assembly comprises a cylindrical mixing tile (2) having a central through-hole (10), and a combustion tile (3) having a tip portion (11) aligned with the mixing tile. The tip portion of the combustion tile is coaxially extended into the central cylindrical through-hole of the mixing tile to provide diffusion air delivery passages (14) extending parallel to the axis of the mixing tile between the tip portion and the inner surface of the through-hole of the mixing tile. This const­ ruction can supply a large amount of diffusion air at low pressure and can increase linearity of the combustion gas supplied into a furnace.

Description: The present invention relates to a burner tile assembly used in various firing furnaces or the like. Hitherto, there has been known a burner tile assembly for use in various firing furnaces as disclosed in Japanese Patent Application Publication No. 80-9603. Such a burner tile assembly as shown in Fig. 3 illustrating an example thereof is mainly composed of a high-speed type burner 21, a cylindrical combustion tile 22 aligned with the burner axis for defining a combustion chamber 23 adapted for burning combustible mixed gas injected from the high-speed type burner 21, a plurality of diffusion air nozzles 24 which are arranged around the combustion tile at an angle to the burner axis so as to direct diffusion air supplied under a medium pressure of 500∼1000 mm Aq. to the combustion gas out of the combustion chamber, and a mixing tile 25 adapted for mixing the combustion gas from the combustion chamber and the diffusion air from the diffusion air nozzles and for directing the mixture of gases into a firing furnace. The mixing tile 25 is formed as a part of a side wall 26 of the firing furnace so as to support its load by bricks of the side wall 26, but is not integrally formed with the side wall. In conventional burner tile assembly as mentioned above, however the amount of air which can be supplied is restricted since the diffusion air is supplied by means of a plurality of nozzles and the pressure of air is decreased since the nozzles are inclined at an angle to the burner axis. In order to deliver a lot of air from the diffusion air nozzles 24, it is required to supply the air under a medium pressure as mentioned above. Moreover, the burner tile assembly is not integrally combined and hence the mixing tile 25 must be arranged as a part of the sidewall, but cannot be mounted on a fiber side wall having a low mechanical strength. FR-A-1433535 discloses a burner tile assembly having the features of the first part of present claim 1. It is an object of the present invention to overcome the above problems, and to provide a burner tile assembly by which a lot of air can be supplied under low pressure and which is mountable on a side wall having a low mechanical strength. According to the present invention, there is provided a burner tile assembly as set out in claim 1. It is prefered that the inner surface of the through-hole is cylindrical and that the burner tile and the mixing tile are integrally combined in a unitary structure. According to the above arrangement, it is possible to easily provide a diffusion air delivery passages having a larger sectional area than that of the conventional nozzles so that a lot of diffusion air can be supplied under low pressure, for example 0∼500 mm Aq. and to direct the delivered diffusion air in parallel with the flow of combustion gas from the combustion tile so that the linearity of the combustion gas is increased. With thus integrally assembling the mixing tile and combustion tile, when the burner tile assembly is applied for the side wall of the firing furnace, all the integrally assembled burner tile can be supported by an outer frame of the furnace body and hence the burner tile assembly can be attached to the side wall constructed of fiber or the other material having a low mechanical strength. These and other optional features and advantages of the invention will be appreciated upon reading of the following description of the invention when taken in conjunction with the attached drawings. Fig. 1 is a longitudinal sectional view of an embodiment of high-speed type burner tile assembly according to the present invention; Fig. 2 is a front end view taken on line II-II in Fig. 1; Fig. 3 is a longitudinal sectional view of a prior art high-speed type burner tile assembly; and Fig. 4 is a front end view taken on line V-V in Fig. 3. Referring to Figs. 1 and 2 illustrating one embodiment of a high-speed type burner tile assembly for use in a firing furnace according to the present invention, a high-speed burner 1 is mainly composed of a cylindrical mixing tile 2 and a combustion tile 3. These tiles 1 and 2 are integrally assembled together with additional tile members 4 and 5 at a predetermined position in a frame 6 which may be supported on an outer frame 7 and/or a side wall 8 of the furnace. The mixing tile 2 has a central through-hole 9 having a cylindrical inner surface 10. The combustion tile 3 has a reduced front end portion or tip portion 11 having a plurality of axial ridges 12 spaced apart circumferentially. The mixing tile 2 and the combustion tile 3 are aligned with a burner 13 and the tip portion 11 of the combustion tile 3 is coaxially extended into the central through-hole 9 of the mixing tile 2 to provide diffusion air delivery passages 14 extending in parallel with the axis of the burner 13 and hence the axis of the mixing tile 2 between the tip portion 11 and the inner surface 10 of the through-hole 9. Each air delivery passage 14 is actually defined by the inner surface 10 and ridges 12 on the outer surface of the tip portion 11. The burner tile assembly constructed as mentioned above can provide wide diffusion air delivery passages and supply the diffusion air into the furnace in a direction parallel to the common central axis of the burner 21, combustion tile 3 and the mixing tile 2. Moreover, the integrally assembled high-speed type burner tile assembly 1 can be inserted into a hole 15 which is formed in the side wall 8 of the furnace and has a shape corresponding to the shape of the front end portion of the mixing tile 2 and the frame 6 with a seal 16, while the frame 6 is supported on the outer frame 7 of the furnace. Accordingly, the burner tile assembly can be attached to the side wall 9 without any load subjected to the side wall 9. The above embodiment is provided with four ridges to divide the space between the tip portion of the combustion tile and the inner surface of the mixing tile to provide four diffusion air delivery passages, but the number of the ridges may be changed with same effect. The diffusion air delivery passages are sufficient to extend in parallel with the common central axis at least at the tip portion of the combustion tile, while the other portion of the diffusion air delivery passages may be formed in various shape. it is seen from the above description that the high-speed type burner tile assembly of the present invention can provide wide opening for delivering diffusion air to supply a lot of diffusion air under low pressure to thereby permit to control air fuel ratio in a large range of 0.7∼7. Moreover, since at least at the tip portion the diffusion air delivery passages are extended in parallel with the common central axis of the burner, combustion tile and mixing tile, linearity of the combustion gas can be increased. Furthermore, the burner tile assembly of the present invention can be attached to the side wall of the furnace made of fiber or the other material having a low mechanical strength because the mixing tile and the combustion tile are integrally combined to provide an integral burner tile assembly which can be substantially supported by the outer frame of the furnace.

Claims: A burner tile assembly comprising a mixing tile (2) having a central through-hole (9), and a combustion tile (3) having a tip portion (11) which is aligned with the mixing tile and coaxially extends into the central through-hole of the mixing tile to provide a diffusion air delivery passage (14) extending in parallel with the axis of the mixing tile between the top portion (11) and the inner surface of the through-hole (9) of the mixing tile, characterized in that said tip portion (11) of the combustion tile (3) has a plurality of axial ridges (12) projecting from its outer peripheral surface and equidistantly spaced circumferentially, so as to provide a plurality of said diffusion air delivery passages (14) extending parallel to each other. A burner tile assembly as claimed in claim 1, wherein the inner surface of the through-hole (9) of the mixing tile (2) is cylindrical. A burner tile assembly as claimed in claim 1 or claim 2, wherein the combustion tile (3) and the mixing tile (2) are integrally combined. A burner tile assembly as claimed in any one of claims 1 to 3, wherein the assembly further includes a supporting outer frame.

Inventors: OGURA KOUJI, YAMAGUCHI MAKIO, OGURA, KOUJI, YAMAGUCHI, MAKIO
Applicants: NGK INSULATORS LTD, NGK INSULATORS, LTD.
Application year: 1990
Main classification: F23D21
IPC codes: F23M5, F23C7, F23D14, F23C3