Patent Application
20100252018
None
None
Portions of the disclosure of this patent document contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyright rights whatsoever.
The invention concerns a wall lining for industrial ovens for protection of wall components from corrosion. The wall structure can be stratified of concrete, steel, sheet metal and/or similar heat resistant layers.
In industrial applications, ovens are installed, which are enclosed within high temperature resistant materials. In the operation of such ovens, interior temperatures may exceed 1000° Celsius (hereinafter “° C.”). The heat-resistant walls of such ovens are exposed to the environment on the outside and exhibit a surface temperature substantially less than that of the interior. At a general room temperature of 20° C., the outer wall temperature may be, for example, 60° C., while the interior wall exposed to the operating temperature stands between 400 to 900° C. The high-temperature resistant material, of which the oven wall is composed, is thus subjected to extreme variances in temperature. Under these conditions a danger exists, that fissures can form in the wall material.
Thus a problem arises that aggressive gases arising within the oven can migrate through such fissures and attack the positioned layers and casing in the wall. The result is that a debilitating corrosion occurs.
The present invention has the purpose of protecting the wall of an oven from such destructive corrosion, wherein the wall is composed of concrete, steel, sheet metal and/or similar heat resistant materials.
This purpose is achieved, in accord with the invention, in that the construction of the wall consists of at least two layers, wherein one of the layers is a pressurized air, predetermined sized enclosure.
Especially highly recommended types of invented wall construction are described and explained in subordinate claims.
Advantageously, a mechanical binding exists between layers which successively form the wall. The most inner of the layers consists of heat-resistant material such as a high-temperature resistant material or concrete (hereinafter referred to as “refractory”), which is fastened in place by metallic anchors or similar steel fasteners. The blocking layer holding pressurized air, as described below, is found between this inner refractory and an outer steel casing. The invented, pressurized, blocking layer can also be placed between an insulation layer and the refractory layer, whereby, fissures in the refractory material lead aggressive gas to engage the blocking pressurized layer. Unlike the aggressive gas from the oven, the pressurizing medium is inert and is normally air. The feeding of this pressurizing air is accomplished with known means, while the pressure and flow thereof are controlled by standard methods.
Advantageously, the pressurized air layer can be filled with a porous material. That is to say, the filling could be comprised of a ceramic fiber or a foamed substance. In this way, the achievement is gained, first, that a pressurized, air filled blocking layer is obtained, which repels the attack of corrosive gas, and second, by means of the mechanical stability of a highly porous layer, the required mechanical binding between the layers is assured.
In accordance with another especially recommended method of construction, protrusions, at predetermined intervals, extend themselves from the refractory layer to penetrate the pressurized, air filled blocking layer. These protrusions assure that a known spatial interval exists between the support points within the blocking layer, whereby, again, the required binding between the layers remains intact. Additionally, as described below, metal anchors are advantageously arranged, that the surfaces of the above-said metallic anchors subject to corrosive attack are enveloped in a flow of moving, inert air.
In the case of an additional, especially highly recommended method of construction, the metallic anchors, which serve for fastening the lining, protrude through the pressurized blocking layer. They are coated with a substance which will change its properties when subjected to operational temperatures. This change can include one or more of the following states: melting, burning, softening, shrinking, contracting, sublimation, evaporation, or slowly vaporizing.
This material accordingly disappears at operating temperatures leaving a void, so that the pressurized air can enter and envelope the anchoring. In this way, the anchors are better protected from the corrosion of aggressive oven generated gases.
In accordance with another preferred embodiment, the blocking layer has the character of at least a single enclosed chamber, filled with pressurized air. In this embodiment, a closed space exists between the described high temperature lining and the casing which can be filled with pressurized air. In the case of this arrangement, no mechanical binding between the layers is necessary.
In many industrial processes, operating ovens possess a sheet metal casing. In accordance with the invention, this casing is designed to be protected with at least one layer of heat resistant material, whereby, between the heat resistant material and the sheet metal, at least one layer of pressurized air is present. This now blocking air layer considerably obstructs the progress of aggressive gas toward the sheet metal casing.
The casing 1 is sheet metal. This casing 1 encloses three layers of the wall, namely, in order from the oven interior outward: a refractory layer 4, pressurized air layer 3 and the insulating layer 2. The refractory layer 4 is composed of a high heat resistant material 5, which is fastened to the outer casing by metallic anchors 6. Between the refractory layer 4 and the casing 1, is a pressurized air layer 3 and an insulation layer 2. The blocking layer 3 is supplied with air by an inlet tube 7 so that chamber 3 advantageously becomes pressurized. This blocking layer can remain either empty or may be filled with a highly porous material. In either case, the layer is subjected to pressurized air. In this blocking layer 3, projections 8 are aligned, spaced at predetermined intervals. These determine the width of the open spacing between the casing refractory layer 4 and the insulation layer 2. The interval projections 8 protrude from the refractory material 5 of the refractory layer 4. The metallic anchor 6, with which the refractory layer 4 is stabilized onto the casing 1, penetrates through the blocking layer 3 as well as through the insulation layer 2. These metallic anchors 6 can be encapsulated in a selected substance, which change characteristics in the presence of operating temperature, such as: melting, burning, softening, shrinking, contracting, sublimation, evaporation, or slowly vaporizing. This temporary encapsulation material disappears at operating temperatures, leaving an empty space, so that the protective air, being pumped into the blocking layer 3 can flow about these anchors, thus protecting them from corrosion.
In the presentation of
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/EP2008/009856 | Dec 2007 | EP | regional |
This application claims the benefit of the priority filing date in PCT/EP2008/009856 referenced in WIPO Publication WO/2009/080167. The earliest priority date claimed is Dec. 22, 2007.
