FR2475692A1 - BURNER FOR BURNER MOLD MADE FROM A MIXTURE OF CERAMIC FIBERS RESISTANT TO HIGH TEMPERATURES, ESPECIALLY FOR THERMAL PROCESSING FURNACES - Google Patents

Abstract

BURNER MITT BRICK MADE OF A MIXTURE OF CERAMIC FIBERS RESISTANT TO HIGH TEMPERATURES, IN PARTICULAR FOR THERMAL TREATMENT OVENS. A SEPARATE INNER BUSH 2, MADE OF REFRACTORY MATERIAL, IS REMOVABLE INSERTED IN BURNER HOLE 3 OF BRICK 1.

Description

Brick for burner muffle made of a mixture of ceramic fibers

  resistant to high temperatures,

  particularly for heat treatment furnaces.

  The present invention relates to a brick for burner muffle made with a mixture of ceramic fibers resistant to high temperatures, and intended in particular for heat treatment furnaces equipped with high speed burners,

  this brick having a burner hole.

  Such bricks for burner muffles are

  in themselves, for example by the magazine "Gas und Wârme", volume 28 (1979), no. 4, page 227, and by the advertisement "Combustion Chamber" of JOHNS-MANVILLE, printed IN- 489 A of March 1966. Such bricks can be made without joints and in one piece by the vacuum molding process, and thus easily adapted to the

  configuration and dimensions of the different types of burners

  their. As ceramic fibers, it is mainly used

  those which are based on alumina silicate, because they allow to obtain, with a low weight, a good thermal insulation

  and low heat build-up, exceptional resistance

  temperature variations and, as a result, optimum durability and operational safety. The brick, which is normally in one piece, can also be in several pieces which are molded individually and joined to each other by gluing, when its dimensions are relatively large. Thanks to the bricks made with ceramic fiber mixtures, it has been possible to obtain an improvement

  notable, particularly with regard to the resistance to

  temperature, hitherto very deficient, compared to fired bricks, prefabricated elements that have undergone annealing or firing, as well as refractory and rammed concretes put in place locally, which were used until now. and which are all based on alumina silicate with different levels of Al 2 O 3, binder and raw materials. It was also possible to avoid joint stresses, which rapidly caused cracking and bursting, thereby impairing the operation of the burners and allowing leakage of unburned gases. The weak

  specific gravity of bricks made with ceramic fibers

  which is only about 10% of that of the bricks or masses that we have been using so far, and which is accompanied by a low heat build-up and thus a rapid cooling, has also made it possible to quickly replace damaged parts, and also makes it possible to put the new burner bricks into operation immediately, without the need to apply specific directives.

  for drying or temperature rise.

  However, bricks for burner muffles made with a mixture of ceramic fibers resistant to

  high temperatures and of a known type have the disadvantage

  the following: high gas and air velocities, as they exist in high-capacity burners, or in other types of burners, turbulence can lead to rapid erosion of ceramic fibers. in the burner hole and thus cause disturbances

of combustion.

  The object of the present invention is to develop and improve the design of a brick for burner muffle of the type described in the preamble, in such a way that, while preserving the advantages previously mentioned in the fields of the technique of heat and regulation, it is possible to avoid to a large extent that the

  burner is damaged by erosion, or that it is pos-

  sible to quickly remedy it.

  The present invention solves the problem that a separate inner sleeve of refractory material is removably inserted into the

  burner hole. This inner sleeve is preferably not

  a small wall thickness and may, depending on the given conditions, be in the form of a cylinder, a truncated cone, or any other configuration, and is, for example, made of silicon carbide, alumina silicate, = ceramic based on oxides, ceramic fibers bonded with a mineral binder, etc. As a separate wear part, the inner sleeve can be replaced in operation. The benefits of ceramic fiber bricks for heat technology and for the control of combustion have so far hardly been realized because of the low wear resistance of this material because the The short lifetime that could be expected from these bricks gave rise to frequent and costly exchanges, as well as disturbances and / or interruptions in operation, whereas the solution according to the present invention makes it possible to reduce to a minimum the costs of the necessary renewal of the bricks, since the fiber-based burner blocks are never exposed

  directly to erosion and thus reach useful lives.

  exceptionally long

  Suitable arrangements or methods of securing the inner sleeve in the burner hole are that said inner socket is interlockingly inserted into the burner hole, is pressed into it by turning with a knurling and / or or is snapped into it

using a lock.

  To obtain an absolute seal between the burner hole and the separate inner sleeve, it is provided that the inner surface of the burner hole and / or the outer surface of the inner sleeve may have a seal, for example mortar or in cement

or refractory mastic.

  The inner sleeve may have a flange or flange, integrally formed on the end face, and through which said inner sleeve may, for example, be screwed, pegged or glued to the burner orifice by means of a round or square steel plate, with interposition of a sealing ring, for example made of refractory or fireproof felt, in such a way that any escape of the combustion gases is prevented. burner hole and thus also the inner sleeve have a flare directed towards the inside of the oven, and that, therefore, the installation of the inner sleeve must be from the inside, said inner sleeve can advantageously being longer, in the direction of the axis, than the burner hole, and may have, at its end located outside, a peripheral groove in which can engage a locking ring ensuring the tanchéité, which is itself held on the brick by a flange or collar for fixing the burner flange spanning said ring. The present invention will be better understood using

  of the detailed description of several embodiments

  FIG. 1 is a diagrammatic sectional view of an embodiment of a burner muffle brick having the features of the present invention, and on which FIG. insertion of the inner sleeve can be done from the outside; FIG. 2 is a view of another embodiment

  of a brick for burner muffle according to the present invention.

  on which the insertion of the inner socket

to get inside.

  Brick 1 for burner muffle according to Figure 1 is adjusted in the masonry 7, for example an industrial heat treatment furnace. In this case, the brick 1 has a cylindrical burner hole 3. According to the present invention, a separate inner sleeve of a refractory material is removably inserted into the burner hole 3. In the embodiment shown in FIG. 1, the inner sleeve 2 is fixed in the hole 3, by means of a knurling 4. Said inner sleeve 2 carries, at its outer end, a fastening flange 5 which is housed in a corresponding annular recess of the brick 1, so that the front face of the flange or fastening collar 5 aligns with the front face of the brick 1. The inner sleeve 2 is held in this position by means of a flange or flange of

  fixing 9 of the burner, flange which is screwed on the outer sheet

  of the furnace shell 8. To prevent leakage of the combustion gases, a seal is ensured by the fact that a sealing ring 11 made of refractory or fireproof felt mat is inserted into a corresponding recess of the furnace shell 8, between the front face of the the fixing flange 5 and

  the inner face of the flange or flange 9.

  The drawn representation also illustrates, by lines in broken lines, how the casing 10 of the burner protrudes inside the burner hole 3 equipped with the socket

inside 2.

  In the case of the embodiment according to FIG.

  the burner hole 3 and therefore also the inner sleeve

  2 have a flared section 12 facing the

  inside the oven. Because of this arrangement, the inner sleeve must be inserted into the burner hole 3 from the inside. But in this case also, the fixing and sealing must also be made from the outside. For this purpose, the inner sleeve 2 has, in the direction of the axis, a length slightly greater than that of the burner hole 3. The inner sleeve 2 carries, at its end which projects outwardly of the burner hole 3, an outer peripheral groove 6, in which

  can mesh, by a suitable spring, a locking ring

  13 which is, for example, in two parts and also serves for sealing purposes. Between the locking ring 13 and the front face of the brick 1, a separate sealing ring 11, which surrounds the inner sleeve 2, can be

  disposed again in a recess of the casing 8 of the furnace.

  The locking ring 13 and the sealing ring 11 are held together in place by a flange or collar of

  fixing 9 which is screwed on the casing 8 of the oven.

at 75692

Claims (5)

  1. Brick for burner muffle made with a mixture of ceramic fibers resistant to high temperatures, and intended in particular for heat treatment furnaces equipped with high-speed burners, this brick comprising   a burner hole, characterized in that a sleeve   (2) separated, made of a refractory material, is inserted   removably in the burner hole (3).   2. Brick for burner muffle according to claim   cation 1, characterized in that the inner sleeve (2) is inserted with interpenetration connection into the burner hole (3) -, is pressed therein by turning with a knurling   (4) and / or is latched therewith a lock.   3. Brick for burner muffle according to some   of claims 1 or 2, characterized in that the   Inner surface Idu burner hole (3) and / or surface   outside of the inner sleeve <2) have a   sealing, eg mortar or cement or refractory mastic.   4. Brick for burner muffle according to any   of claims 1 to 3, characterized in that the   inner sleeve (2) has a flange or flange of fixation (5).   5. Brick for burner muffle according to any one   one of claims 1 to 4, characterized in that   inner sleeve (2) is longer in the direction of the axis than the burner hole (3) and has at its end located   outside, a peripheral groove (6).