Inpaled And Compressed Fibrous Furnace Lining

Abstract

An arrangement for lining a furnace wall wherein strips of fibrous insulating material are impaled and compressed to form a furnace wall lining with the fibrous material protecting the lining supports.

Description

This invention relates in general to the lining of furnaces, and more particularly to the lining of a soaking pit cover where the lining is fabricated from flexible blankets of fibrous insulating material such as Kaowool (TM), glass fibers and the like.

In the construction and operation of various types of furnaces the walls and roof are ordinarily lined with refractory materials which are capable of withstanding the temperatures prevailing on the interior of the furnace. Heretofore fibrous blanket materials have been used to some extent in lining such furnaces, particularly when the temperatures involved have not exceeded approximately 2000.degree.F. There are many advantages to the use of fibrous materials which are well known in the furnace art. One particular application of fibrous furnace linings has not heretofore been successfully accomplished due to installation and maintenance difficulties. This problem occurs particularly in furnaces of the soaking pit variety where the roof of the furnace is periodically moved to provide access to the furnace, either in charging or removing the material being heated in the soaking pit. The traditional lining for a soaking pit cover has involved the use of dense refractories which adds considerably to the weight of the cover, and makes it rather difficult insofar as maintenance is concerned due to heat shock to the refractory.

In accordance with the present invention I provide an arrangement for supporting a soaking pit cover lining formed of fibrous blanket material which is not subjected to thermal shock and accordingly has a considerable greater life as compared with dense fire brick linings heretofore in use, and drastically reduces the weight of the soaking pit cover.

In my arrangement strips of fibrous blanket material are compressed to form the sections of the walls such as in panels, where the metallic parts exerting the compression pressure on the blanket material are buried in the material and thereby protected against the high furnace temperatures to which the surface of the liner is exposed during normal operations.

IN THE DRAWINGS:

FIG. 1 is a partial elevation, in section, of a furnace wall construction arranged in accordance with the present invention;

FIG. 2 is a plain view, partially in section, showing a portion of the furnace wall arrangement of FIG. 1;

FIG. 3 is an enlarged segment of a portion of the furnace wall arrangement shown in FIG. 1;

FIG. 4 is in view taken on the line 4--4 of FIG. 3; and

FIG. 5 is a plan view of an alternate furnace wall construction.

It will be understood that while the present invention is particularly applicable to the construction of soaking pit covers the construction used in forming the roof may also be used on upright wall portions of a furnace whether the walls are fixed in their relationship to the furnace or are movable as, for example, in an upright furnace door.

In the embodiment shown, a corner of a furnace as shown in FIG. 1 includes a portion of a furnace roof 10 and a portion of one upright side wall 11 enclosing a furnace space 12. The lining of the furnace is formed of strips of fibrous material 13 which are assembled in an impaled and compressed condition in panels 14, with a plurality of panels arranged in side by side array to cover the exposed surface of a furnace wall or walls. Depending upon the surface area and the dimensions of the furnace to be protected the panels may also be arranged in end to end relation. Under some circumstances a panel may consist of an entire wall surface. Good practice requires the metallic portion of the panels, as hereinafter described, are spaced. Such spacing will be of the nature of 1/2 inch more or less between panels, depending upon the size of the individual panels.

Advantageously, with the construction, hereinafter described, the panels 14 for any particular furnace will be assembled away from the furnace, and after assembly may then be installed on the furnace walls or roof, as desired, with either welded or bolted mounting in the furnace frame.

Each panel 14 is formed with a flat metallic base plate 15, ordinarily of steel, and will be provided with angles 16 forming the sides and ends of the panel. The strips of fibrous insulating material 13 are inserted in the panel and held in place by impaling rods, or threaded bolts 21, with the fibrous strips compressed to fit in a panel, for example in the embodiment of FIG. 1 the panel is 3 feet by 4 feet. In this particular instance the overall dimensions of the furnace wall to be covered permits a plurality of panels of this size to complete the entire wall coverage such as roof 10. As shown, the base plate 15 is provided with angle irons 20 which are 3 inches by 11/2 inch by 10 gauge, stainless steel. These angles are perforated, as hereinafter described, and as shown each angle 20 is provided with threaded bolts 21 welded to the upright flange 22 of the angle at a position generally about 1/2 inch from the end of the flange. The base 23 of the angle 20 is welded to the base plate 15 so that when assembled angles 20 are approximately 6 inches apart. The threaded bolts are 7 inches long and, as shown, 8 strips of 1 inch thick and 6 inches wide fibrous insulating material 13 is impaled on the threaded bolts 21 and compressed into the 7 inch space. Each threaded bolt is provided with a washer 25 and a nut 26 (see FIG. 4) which compresses the 8- 1 inch wide strips into a 7 inch spacing.

As shown particularly in FIGS. 1 and 2 the bolts 21 are alternately spaced on the upright flanges 22 of the angles 20 on approximately 10 inch spacing. Each of the angles is perforated as at 30 as shown in FIG. 4 to accommodate the washer 25 and nut 26 of a threaded bolt 21 from the next adjacent angle 20.

With this construction, an approximately 3 inch layer of fiberized insulating material covers all of the metallic parts of the panel. It will be apparent that compressing one end portion of the strips 13 will permit the outer portion to "blouse" so that on the furnace side of the panel the insulating material will be continuous to protect the metallic parts of the panel.

In referring to FIG. 3 it will be noted that each of the metallic bases 15 of each panel is provided with a structural support 33 at each end. In the embodiment shown, the supports 33 are in the form of a channel iron. One leg of the channel is welded or otherwise secured to the base 15 of the panel while the other end of the channel will be bolted to structural steel work (not shown) supporting the wall. This type of construction is useable for either the roof or the side walls of the furnace.

While the width of the panel may be 3 feet, as hereinbefore described, with the length 4 feet it will of course be understood that the length of the fibrous strips will be slightly greater than 4 feet to permit overlapping of the ends of the fibrous strips beyond the edge of the panel flange.

It will be understood that other forms of impaling and compressing these strips of fibrous insulating material may be utilized. For example each angle 20A may be provided with stainless steel rods 21A and 21B extending on opposite sides thereof. Under these circumstances the length of the rod will be less than the spacing between angles so as to permit overlapping of the staggered rods to maintain the strips of fibrous materials in position in the panel. Moreover, the base of each angle may be bolted to the base plate 15, instead of being welded, to facilitate maintenance and replacement of portions of a panel when this becomes desirable. Under such circumstances it would not be necessary to perforate the upright flange of the angle such as shown in FIG. 4. Likewise, it would not be necessary to utilize washers and a nut to maintain the compressed condition of the fiberized strips.

In the illustrated embodiment of the invention shown in the drawings the compression of the strips is equal to approximately 15 percent, in other words the 8 inch original width of the strips in the compressed condition has been compressed to 7 inches. Under some circumstances and at the election of the furnace designer the compression of the fiberized strips may be greater or less than that indicated. In one installation of the general type described the compression allowed sufficient blousing on the innermost portion of the insulating material to protect the metallic parts of the panel from the heat in the furnace.

In the embodiment shown in FIG. 1 the present invention is illustrated as being applied for both the roof and upright wall of the furnace. If the upright wall is designed to be moveable or the roof designed to be moveable it is desirable to provide an insulating seal at the corner of the furnace. In the embodiment shown, this seal takes the form of a double layer of insulating strip material 40 fixed in position relative to the upright wall 11 of the furnace while a double pair of insulating blanket strips 41 and 42 are constructed with wire mesh 43, maintained in relative position by suitable bolts 44 and longitudinal extending bars 45 so that some amount of wear will occur with this seal and the sealing arrangement may need replacement more frequently than the panels in the furnace wall. However, replacement of panels and general maintenance costs have proven to be extremely low in furnace walls constructed as described, when compared with solid refractory roof and wall structures. This has been true only when the fibrous insulation is not directly exposed to flame inpingement and flame erosion. This drawback to the use of fibrous insulation is well known and recognized in the art.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An insulation support system for a furnace wall which comprises a plurality of panels arranged in side by side relation on the furnace wall, each panel including a metallic base member and metallic members having a flange attached in transversely spaced attached relation to and extending outwardly of the base member, and means including rods attached to the outwardly extending flanges and extending parallel to and spaced from the base of the panel for impaling and compressing a plurality of strips of heat insulating fibrous materials between flanges within each of the panels to provide a thickness of insulating fibrous materials between the interior of the furance and the metallic parts of the panels.

2. An insulation support system according to claim 1 wherein the furnace wall consists of the furnace roof.

3. An insulation support system according to claim 2 wherein the furnace is a soaking pit with a removable roof.

4. An insulation support system according to claim 1 wherein the rods extend from one side of the flange, are longer than the spacing between the attached flanges and the flanges are perforated to accommodate the end portion of a rod attached to an adjacent flange.

5. An insulation support system according to claim 4 wherein the rods are threaded and the strips of heat insulating fibrous material is compressed by a threaded nut and washer attached to an end of a rod.

6. An insulation support system according to claim 1 wherein the rods are less than the spacing between adjacent flanges, and extend in opposite directions from the flanges.