Burner tile, burner, and furnace

1. A burner tile including a molded inorganic fiber product and having a burner main hole extending therethrough in a furnace interior-exterior direction, the burner tile comprising:

an inner layer surrounding the main hole and an outer layer surrounding an outer circumferential surface of the inner layer, the inner layer and the outer layer being included in at least part of the burner tile adjacent to a furnace interior,

the inner layer including inorganic fiber rods arranged and combined such that end surfaces of the rods extend substantially radially from the main hole,

the outer layer including a laminate wrapped several turns around the outer circumferential surface of the inner layer,

wherein the laminate is formed by a plurality of superposed inorganic fiber blankets having different bulk densities.

2. The burner tile according to claim 1 , wherein the bulk density of the burner tile decreases in a radially outward direction.

3. The burner tile according to claim 1 ,

wherein the inner layer is included in only the part of the burner tile adjacent to the furnace interior, and

wherein the outer layer defines an inner circumferential surface of the main hole in part of the burner tile adjacent to a furnace exterior.

4. The burner tile according to claim 1 , wherein the percentage of T 1 /T 0 is 20% to 70% where T 0 denotes the thickness of the burner tile and T 1 denotes the average thickness of the inner layer in a cross-section in which the burner tile has a minimum thickness in its radial direction relative to the axis of the main hole.

5. The burner tile according to claim 1 , wherein the inorganic fiber rods included in the inner layer include rods having a triangular or trapezoidal cross-section perpendicular to the axis of the main hole and rods having a rectangular cross-section perpendicular to the axis of the main hole.

6. The burner tile according to claim 1 , wherein the burner tile is shaped so as to have a square outside shape in a cross-section perpendicular to the axis of the main hole.

7. The burner tile according to claim 1 , wherein part of the burner tile extending along an inner circumferential surface of the main hole has a bulk density of 0.3 to 1.0 g/cm 3 .

8. The burner tile according to claim 7 , wherein the burner tile includes inorganic fibers and a binder-derived material caused by oxidation of an inorganic binder binding the inorganic fibers, and the amount of the binder-derived material per unit volume in the part extending along the inner circumferential surface of the main hole is greater than that in the intermediate region.

9. The burner tile according to claim 1 , wherein Di-Dm is 0.05 to 3.0 g/cm 3 where Di denotes a bulk density of part extending from an inner circumferential surface of the main hole to a depth of 5 mm and Dm denotes a bulk density in an intermediate region when a cross-section of the burner tile perpendicular to the axis of the main hole is equally divided into three regions that are an inner region adjacent to the main hole, an outer region adjacent to an outer surface of the burner tile, and the intermediate region between the inner and outer regions.

10. The burner tile according to claim 9 , wherein Dm/Di is 0.1 to 0.9.

11. The burner tile according to claim 1 , wherein the inorganic fiber is alumina-based fiber.

12. The burner tile according to claim 11 , wherein the alumina-based fiber is crystalline alumina silica fiber containing greater than or equal to 65 wt % alumina.

13. The burner tile according to claim 1 ,

wherein the burner tile is composed of a cylindrical member fitted in part of an inner circumferential surface of the main hole adjacent to the furnace interior and a main body in which the cylindrical member is detachably fitted, and

wherein the burner tile further includes a protrusion that prevents the cylindrical member from separating from the main body and moving toward the furnace interior.

14. A burner comprising the burner tile according to claim 1 .

15. A furnace comprising the burner according to claim 14 .

16. A method for producing the burner tile according to claim 1 , the method comprising:

arranging inorganic fiber rods on at least part of a core mold having a shape of the main hole adjacent to a furnace interior whereby end surfaces of the rods extend radially;

wrapping an inorganic fiber laminate around at least outer surfaces of the rods to form an inorganic fiber roll;

compressing by pressing shaping plates against an outer surface of the inorganic fiber roll toward the center of the roll to compress the roll, and coupling the shaping plates to the core mold to maintain the compressed inorganic fiber roll as a compressed product;

impregnating the compressed product in an inorganic-binder-containing liquid;

drying the compressed product impregnated with the inorganic-binder-containing liquid;

releasing by removing the core mold and the shaping plates from the dried compressed product; and

firing the compressed product after removal.

17. The method for producing a burner tile according to claim 16 , wherein the core mold and the shaping plates have holes for passing the inorganic-binder-containing liquid therethrough.

18. The method for producing a burner tile according to claim 17 , wherein the method further comprises sucking part of the inorganic-binder-containing liquid held in the compressed product through the core mold.

19. A burner tile including a molded inorganic fiber product and having a burner main hole extending therethrough in a furnace interior-exterior direction, the burner tile comprising:

high bulk density part that extends along an inner circumferential surface of the main hole and has a higher bulk density than intermediate part located between the inner circumferential surface and an outer surface of the burner tile,

wherein the burner tile includes an outer part formed by rolling a plurality of superposed inorganic fiber blankets having different bulk densities several turns.