EP0077608B1

EP0077608B1 - Thermally insulative modules for lining furnaces or like equipment

Info

Publication number: EP0077608B1
Application number: EP82304821A
Authority: EP
Inventors: Roger Charles Oxford; Alan Corbett Ferguson; Melvin Leon Gordon
Original assignee: Babcock and Wilcox Co
Current assignee: Cessione thermal Ceramics Inc
Priority date: 1981-10-16
Filing date: 1982-09-13
Publication date: 1986-12-10
Also published as: JPH0239200Y2; IN162731B; JPS6163696U; EP0077608A1; ES8403605A1; ES516527A0; JPS58501593A; AU557614B2; BR8207875A; ZA826725B; CA1210239A; WO1983001475A1; AU8953282A; DE3274678D1; MX161643A; PH24054A; AR230514A1

Description

The present invention relates to thermally insulative modules for lining furnaces or like equipment.
Several ceramic fibre modular designs for furnace linings presently exist. Many such modules comprise individual strips of refractory fibre blanket stacked edgewise and either cemented to an expanded metal substrate by means of ceramic cement or mortar, or held together by retainer members having a base portion running the length of the individual strips, as exemplified in US Patents Nos. US―A―3 940 244 and US―A―3 832 815. Other known modular designs are composed of a compressed continuous strip of pleated thermally insulative blanket with two of the outer pleats (cold face pleats) mechanically supported by its metal frame. The supports run substantially the length of the fold or pleat. The module's metal frame allows it to successively attach to the adjacent modules. Once attached, the modules are mounted to the furnace walls using studs or fastening clips affixed to the walls, as exemplified by US Patents Nos. US―A― 4 001 996 and US-A-4 103 469.
However, problems still exist with certain types of insulation modules. Ceramic fibre blankets and, therefore, the modules made thereof are not mechanically strong and must be handled with great care to avoid tearing. Ceramic fibre blanket material is known to shrink when exposed to temperatures in excess of 1093°C (2000°F). Known modules utilising blankets of such material for lining of furnaces have encountered difficulties caused by said shrinkage of the material. Shrinkage has caused separations between folds within a module and between modules themselves, thereby exposing the furnace shell and critical retainer members to the heat of the interior of the furnace. Shrinkage has also caused the pleats of a folded blanket configuration to unfold and hence sag since not all cold faced pleats were supported.
US Patent No. US―A―4 287 839 (EP-A-0 013 039) discloses a thermally insulative module for lining a furnace, the module comprising an insulative blanket folded into a plurality of inner folds and outer folds, a support means having a base and a mounting means and a retaining means at each end thereof, the plurality of outer folds of the blanket being positioned between the retaining means of the support means, and fold support rod means extending through the plurality of outer folds of the blanket and attached to the retaining means. Such a module is referred to hereinbelow as "a module of the kind described in US―A―4 287 839".
The base portion of the support means of the module of US―A―4 287 839 is in the form of a base plate whose length and width are substantially the same as the length and width of the module. The mounting means at each end of the support means comprises a pair of hooks rotatably mounted to the base plate. The retaining means at each end of the support means comprises a pair of lugs that are spaced apart in the direction of the width of the module and are bolted or otherwise fixed to the base plate. The lugs are disposed externally of the folded blanket. The fold rod support means comprises two fold support rods that are spaced apart in the direction of the width of the module. Each rod is fixed at each end to a respective one of the two lugs at each end of the module.
The pres nt invention provides a module of the kind described in US-A-4 287 839, characterised in that:

(i) the support means is in the form of an elongate support bracket having an elongate base of width substantially less than that of the folded blanket;
(ii) the mounting means at each end of the elongate support bracket (20) is in the form of a bracket mounting member (26);
(iii) the retaining means at each end of the elongate support bracket (20) is in the form of a protected upturned bracket retaining member (24); and
(iv) the fold support rod means is in the form of a single fold support rod (30) attached at each end to a respective one of the bracket retaining members (24).

The present inventors have found that such a simple structure will function satisfactorily in spite of the above-described problems caused by the fragility and tendency to shrink of the blanket material.
The simplicity of the construction of the arrangement can be enhanced if each bracket mounting member is end-slotted or has at least one hole therein, especially if the slots or holes are sized to accept threaded studs for mounting the module to a furnace or like equipment. The simplicity can further be enhanced if a bracket mounting member comprises an elongate integral extension of the elongate base and/or if a bracket retaining member is integral with the elongate base.
Preferably, the upturned bracket retaining member at each end of the elongate support bracket is protected by virtue of its being disposed between an outer fold and an end flap of the blanket. In this way, the retaining members (as well as the fold support rod) is protected from the environment of the furnace or like equipment by virtue of its being disposed within the body of material defined by the folded blanket.
Modules forming preferred embodiments of the present invention and described hereinbelow can be used to line furnace walls and ceilings. The modules can be attached to a furnace wall or ceiling having threaded studs and/or other fastening devices. The blanket of the preferred modules is under compression before and after installation. The preferred modules resist unravelling and/or lamination of the layers of insulative blanket.
The invention will now be further described, by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which

Figure 1 is an isometric view of a module embodying this invention; and
Figure 2 is an isometric view of another module embodying this invention.

Each figure of the drawings illustrates a rod- anchored, accordion-fold, full-lining thermally insulative module 10 to be used for insulating a furnace or other high temperature equipment. The module 10 is preformed from a folded or pleated ceramic fibre insulating blanket 12 and a support bracket 20. Folds or pleats 14 and 16 exist at the hot or inner and cold or outer faces, respectively, of the module 10. The support bracket 20 has a base 22, and also has a protected upturned retaining member 24 and a mounting member 26 at each end thereof. A pleat support rod 30 extends between the retaining members 24 of each support bracket 20. The rod 30 is threaded perpendicularly through each cold face pleat 16 and is located near the outer or cooler face of the module 10 and parallel thereto.
The outer or cooler face of the module 10, also referred to as the cold face, is defined as that surface of the module which comes into contact with the furnace wall. The hot face of the module 10 is defined as that surface of the module which is exposed to the interior of the furnace. Therefore, the module 10 has both hot face or inner folds or pleats 14 and cold face or outer folds or pleats 16. The pleat support rod 30 not only holds the ceramic fibre blanket 12 in compression, but also serves to retain each pleat 16 within the module 10. Each end of the pleat support rod 30 is attached to a support bracket retaining member 24. Each retaining member 24 is situated between an outer fold and end flap of the module, whereby the member 24 is protected from the detrimental effects of the furnace environment. Any conventional means of attachment can be used. However, the rod 30 will typically be end-threaded so that a nut at each end of the rod will keep the rod secured to the support bracket20.
The folded ceramic fibre insulating blanket 12 is formed from a suitable commercially available ceramic fibre sheet such as the type known under the trademark KAOWOOL and sold by The Babcock & Wilcox Company. It should be understood that the particular type of insulating blanket used is selected in accordance with the range of temperatures in the high temperature equipment in which the apparatus is to be installed.
The folded blanket 12 is compressed prior to being placed within the support members 24 of the support bracket 20. This compression is calculated to compensate for thermal shrinkage of the blanket material that occurs during use of the module. Banding material (not shown) is then placed around the module 10 at or near the two ends so that the banding material is in parallel relationship with the support rod 30. The banding material ensures that the folds and end flaps of the module remain substantially square and compressed during package, shipping and placement. Once installation of the furnace wall or ceiling is complete, the banding material is removed.
A modular block fibre lining formed from a plurality of the modules 10 is typically installed in parquet fashion such that adjacent modules are turned 90° before installation. The present modular design represents a full furnace lining and as such can be used alone. However, if desired, a safety or backup liner layer of wallpaper insulation blanket can be used behind the module as further protection for the furnace shell.
In both the illustrated embodiments the mounting members 26 are end-slotted. The mounting members 26 may instead each have at least one hole therein. In all cases, the members 26 are preferably sized to accept threaded studs (not shown) mounted to the furnace.

Claims

1. A thermally insulative module for lining a furnace or like equipment, the module (10) comprising an insulative blanket (12) folded into a plurality of inner folds (14) and outer folds (16), a support means having a base (22) and a mounting means and a retaining means at each end thereof, the plurality of outer folds (16) of the blanket (12) being positionedbetween the retaining means of the support means, and fold support rod means extending through the plurality of outer folds (16) of the blanket (12) and attached to the retaining means, characterised in that:

(i) the support means is in the form of an elongate support blanket (20) having an elongate base (22) of width substantially less than that of the folded blanket (12);

(ii) the mounting means at each end of the elongate support bracket (20) is in the form of a bracket mounting member (26);

(iii) the retaining means at each end of the elongate support bracket (20) is in the form of a protected upturned bracket retaining member (24); and

(iv) the fold support rod means is in the form of a single fold support rod (30) attached at each end to a respective one of the bracket retaining members (24).

2. A module according to claim 1, wherein the bracket mounting members (26) are end-slotted.

3. A module according to claim 1, wherein each bracket mounting member (26) has at least one hole therein.

4. A module according to claim 2 or claim 3, wherein the slot or hole of each bracket mounting member (26) is sized to accept a threaded stud mounted to a furnace or like equipment.

5. A module according to any one of the preceding claims, wherein a bracket mounting member (26) comprises an elongate integral extension of the elongate base (22).

6. A module according to any one of the preceding claims, wherein a bracket retaining member (24) is integral with the elongate base (22).

7. A module according to any one of the preceding claims, wherein the upturned bracket retaining member (24) at each end of the elongate support bracket (20) is protected by virtue of its being disposed between an outer fold and an end flap of the blanket (12).

8. A module according to any one of the preceding claims, wherein the plurality of outer folds (16) is compressed within the two retaining members (24).

9. A lining for a furnace or like equipment, the lining comprising a plurality of modules (10) according to any one of the preceding claims and an attachment means securing each mounting member (26) of each module (10) to the furnace or like equipment, adjacent modules (10) being mounted such that the plurality of inner folds (14) of one module is in compressive contact with the plurality of inner folds (14) of each of a plurality of adjacent modules.

10. A lining according to claim 9, wherein each module (10) is mounted at a position rotated by 90° with respect to adjacent modules.