US3420213A - Forced air roof-cleaning skewback channel and frame - Google Patents

Description

Jan. 7, 1969 J. H. REIGHART 3,420,213

FORCED AIR ROOF-CLEANING SKEWBACK CHANNEL AND FRAME Filed Sept. 13, 1967 Sheet of 2 Fig. 7

INVENTOR. a Y June HRGLYIMZIZZ 2'- E2 w N ATTORNEYS Jan. 7, 1969 J. H. REIGHART FORCED AIR ROOF-CLEANING SKEWBACK CHANNEL AND FRAME Sheet 2 of Filed Sept. 13, 1967 1NVE.NTOR. JwneIiRez/g BY n mm United States Patent 12 Claims ABSTRACT OF THE DISCLOSURE A forced air roof-cleaning skewback channel for an open hearth furnace having elongated horizontal slots therein located just above the adjacent edge of the roof. A closed corrugation in the web of the skewback channel, just above these slots, serves as a passageway for compressed air or other cleaning media, with downwardly disposed jets to direct a blast of air toward the slots. If no strengthening corrugation is provided in the web of the skewback channel, a welded-on channel member or pipe may be substituted therefor for providing positive motivation of the dust and dirt through the slots.

BACKGROUND OF THE INVENTION Field 0 the invention The invention relates generally to skewback channels for supporting arched furnace roofs of the type disclosed in my prior Patents Nos. 2,919,683, dated Jan. 5, 1960; 2,956,552, dated Oct. 18, 1960 and 3,173,403, dated Mar. 16, 1965, and more particularly to a forced air roofcleaning skewback channel.

In conventional open hearth furnace constructions, the roof arch is supported at opposite sides upon skewback channels mounted upon the usual buck-stays, and the frames of the charging doors of the furnace extend upward in close proximity to the outer sides of the skewback channels.

Fly ash, dust and dirt descend upon the top of the arched furnace roof and slide by gravity down each side of the roof and accumulate thereon against the furnace sides of the skewback channels. With the basic brick furnace roofs which have recently come into general use, the arch of the roof is higher to provide a larger combustion space for introducing oxygen into the furnace and running at higher temperatures.

This construction produces more of a trap between the top of the furnace arch and the skewback channels, whereby the accumulation of fly ash, dust and dirt on the roof becomes an acute problem as it not only has a detrimental effect on the furnace operation, but there is no satisfactory way to remove the accumulation.

The need for the invention is primarily based on the fact that the majority of open hearth furnaces are utilizing chrome magnesite or other basic refractory brick in their roof structures. Such basic refractory brick provides for longer roof life, with less maintenance, and withstands higher operating temperatures demanded where oxygen lances are used.

Such basic brick must be kept relatively free of dust and dirt while operating. If dust and dirt is allowed to accumulate thereon it acts as an insulating blanket or layer on the relatively cold upper face of the brick causing the roof to deteriorate or burn out prematurely.

3,420,213 Patented Jan. 7, 1969 Description of the prior art Attempts have been made to periodically blow the dust and dirt from such basic brick roofs, as disclosed in McLain Patent No. 3,032,327, issued May 1, 1962 and Roudabush Patent No. 3,162,152, issued Dec. 22, 1964. Such cleaning apparatus momentarily removed the dust and dirt from the roof but caused increased compacted and heavy accumulations thereof to settle down in the valleys adjacent to the skewback channels, thus weakening support for the roof within that critical area between the top edges of the roof and the skewback channels.

SUMMARY OF THE INVENTION The invention may be briefly described in general terms as comprising an open hearth furnace construction in which skewback channels and charging door frames are independently supported upon the usual buck-stays of the furnace. The skewback channels are so constructed and positioned that the skew surfaces terminate at or slightly below the top of the arched roof at each side of the furnace.

In a preferred embodiment of the invention, a dust ledge is formed on the skewback channel at the upper edge of the skew surface, as a continuation of the upper surface of the brick roof.

Horizontally disposed slots are formed in the web of the skewback channel, the lower edges of said slots being located at or slightly below this dust ledge, or the top of the adjacent edge of the roof where the dust ledge is omitted.

A horizontally disposed passageway for compressed air is located just above these horizontal slots and provided with downwardly and outwardly disposed jets arranged to direct a blast of air toward the slots. Thus, fly ash, dust and dirt dropping upon the arched roof may slide down opposite sides of the roof by gravity and be discharged across the dust shelf and through said slots.

Each charging door frame is of a modified construction in order to uncover the slots in the web of the skewback channel. For this purpose, the top of the upper water chamber, above the arch of the door frame, is cut off at or slightly below the lower edges of the slots in the web of the skewback channel.

At each side of the door frame, an upwardly disposed extension is provided, vertically aligned with, and of substantially the same cross section as the usual depending legs of the frame. These extensions provide means for locating the vertical inlet and outlet pipes for the watercooling system of the frame.

An angle bracket is attached to the upper ends of these extensions on the frame, reinforcing the top of the frame and providing means for attaching the usual lugs and other hardware to the frame. The ends of this angle bracket are attached to adjacent buck-stays.

The water-cooled nose of the door frame is located beneath the skewback channel protecting the same from impact when charging the furnace, and providing further heat protection for the skewback channel.

The primary object of the present invention is to provide an open hearth or similar furnace construction in which the skewback channels and charging door frames are so constructed and arranged that the arched furnace roof will be substantially self-cleaning.

Another object of the invention is to provide a skewback channel having horizontal slots at the top surfaces 3 of the adjacent edge of the roof and means for directing aniair blast toward said slots.

A further object of the invention is to provide such a skewback channel in which the air passage is formed by closing a strengthening corrugation in the web thereof.

A still further object of the invention is to provide a skewback channel of the character referred to in which the air passage is formed by welding a channel member to the web thereof above the slots.

It is also an object of the invention to provide a skewback channel of this type in which the air passage comprises a pipe welded to the web thereof.

A further object of the invention is to modify the construction of each of the charging door frames by cutting off the top of the upper water chamber of the frame, so that it terminates slightly below the lower edges of the slots in the web of the skew-back channel.

A still further object of the invention is to provide such a modified charging door frame having upwardly disposed extensions at each side edge of the frame, comparable in cross section and vertical alignment with the usual water-cooled legs of the frame, providing means for extending the door guide rails upward, and also for attaching an angle bracket extending across the full width of the frame for reinforcing the top of the frame and for attaching the usual lugs and other hardware thereto.

Another object of the invention is to provide for locating the water-cooled nose of the charging door frame beneath the skewback channel for protecting the skewback channel from impact and for giving added heat protection thereto.

Other objects of the invention are to provide various other modifications of skewback channel associated with the modified construction of charging door frames for providing a substantially self-cleaning furnace roof.

The above and other objects, apparent from the drawings and following description, may be attained, the above described difiiculties overcome and the advantages and results obtained, by the apparatus, construction, arrangements and combinations, subcombinations and parts which comprise the present invention, a preferred embodiment of which, illustrative of the best mode in which applicant has contemplated applying the principle, being set forth in detail in the following description and illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspective view, looking from the outer or floor side, of a portion of an arched furnace roof supported at one side by a skewback channel constructed in accordance with the invention, and showing a charging door frame constructed in accordance with the invention, the usual buck-stays and the angle bracket for the top of the door frame being removed for purpose of illustration;

FIG. 2 is a fragmentary perspective view, looking from the inner or furnace side, showing a portion of an arched furnace roof supported at one side by a portion of a skewback channel embodying the invention, showing a portion of a charging door frame embodying the invention, the usual buck-stays and the angle bracket at the top of the door frame being removed in this view also for purpose of illustration;

FIG. 3 is a front elevation of a charging door frame and a skewback channel embodying the invention, supported upon the usual buck-stays;

FIG. 4 is a top plan view of the parts shown in FIG. 3; FIG. 5 is a vertical transverse section, taken on the line 55, FIG. 3;

FIG. 6 is a transverse sectional view through a preferred form of skewback channel, in which the air passage is formed by closing the strengthening corrugation in the web;

FIG. 7 is a similar view of a slightly modified form of skewback channel;

FIG. 8 is a similar view of a further modification;

FIG. 9 is a transverse sectional view through a modification of the skewback channel in which the air passage is formed by welding an angle member to the web thereof;

FIG. 10 is a similar view of another modification of the skewback channel in which a pipe is welded to the web thereof; and

FIG. 11 is a transverse sectional view of a further modification of the skewback channel in which a pipe is welded to the web thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to the embodiment of the invention illustrated in FIGS. 1-6, in which similar reference characters refer like parts throughout. The usual buckstays, which ordinarily support open-hearth furnace structures, are indicated at 1 in FIGS. 3, 4 and 5. These buckstays are omitted from FIGS. 1 and 2, for the purpose of better illustrating the novel skewback channel and charging door frame to which the invention pertains, since the buck-stays form no part of the invention and merely support the skewback channels and charging doors.

The skewback channel, which is preferably of the water-cooled type as illustrated, is indicated generally at 2. As in usual practice, skewback channels are attached to the buck-stays on opposite sides of the furnace to support the arched brick roof indicated generally at 3. The roof may be formed of basic refractory bricks such as chrome magnesite. The skewback channels may be attached to the buck-stays in any usual and well known manner.

Each skewback channel is provided with upper and lower water chambers 4 and 5 respectively, as shown in FIGS. 5 and 6, for cooling the skew surface 6, which terminates in a substantially horizontal, or preferably slightly downwardly inclined dust ledge 7, located at or slightly below the adjacent portion 8 of the top of the furnace roof.

The usual web 9 extends upward from the back or outer side of each skewback channel, terminating at its upper end in the inturned flange 10. Cooling water may be continuously circulated through the upper and lower chambers 4 and 5 respectively, of each skewback channel, by the usual inlet and outlet pipes 11, as indicated in FIGS. 1, 3 and 4.

A series of horizontal slots 12 are formed in the web 9 of the skewback channel, the lower edges of these slots being flush with the top of the dust ledge 7, and preferably with their lower edges taper-cut in a downwardly and outwardly inclined surface corresponding with the slope of the adjacent roof 3. As clearly shown in FIGS. 1, 2

and 3, each slot is of a length at least twice the distance between slots.

A charging door frame is indicated generally at 13 and comprises an upper water chamber '14 with depending water-cooled legs 15 forming the arched door opening 16 arranged to be normally closed by a water-cooled charging door of any usual construction slidable within the door guides 17 as in usual practice.

For the purpose of uncovering the slots 12 in the skewback channel, the top of the water chamber 14 of the door frame terminates at or slightly below the lower edges of the slots 12, in a downwardly and outwardly inclined surface, as indicated at 18.

Upwardly disposed extensions 19 are formed at each side edge of the door frame, these extensions being in vertical alignment with and of substantially the cross section of the legs 15 of the door. These extensions 19 provide means for extending the door guide rails 17 up and provide means for locating vertical inlet and outlet water pipes 20 and 21 respectively.

The extensions 19 also provide means for attaching an angle bracket, indicated generally at 22, which extends across the full width of the door frame and is connected to the upper ends of the extensions 19, thus reinforcing the top of the door frame and providing means for attaching lugs 23 or other usual hardware to the frame.

The water-cooled nose 24 of the door frame extends beneath the skewback channel 2 to protect the same from impact during charging of the furnace and also giving added heat protection to the skewback channel.

The door frame may be attached to the buck-stays as by the attaching brackets 25, which are connected to opposite ends of the angle bracket 22 and to the buckstays respectively, as by the bolts 26 and 27.

The extension 19 at the outlet side of the frame provides a water-cooled chamber which may extend over the same to the top thereof. On the inlet side the extension 19 is bulk-headed, as indicated at 28, on a level with the top 18 of the upper water chamber 14 of the door frame to form a water feed manifold and avoid the trapping of still water in that isolated section.

With this construction, it will be obvious that fly ash, dust and dirt dropping upon the arched roof 3 of the furnace will by gravity slide down the roof onto the dust ledge 7 of the skewback channel. The greater amount of fly ash and other dirt may slide by gravity across the same and through the slots 12 in the web of the skew-back channel.

The principal feature of the invention is the provision of means for blowing any remaining accumulation of fly ash, dust and the like through the slots 12. For this purpose a passageway for compressed air, or other cleaning media, is located horizontally above the slots 12 and provided with jets disposed downwardly and outwardly to direct an air blast toward the slots.

Where the skewback channel is of the type having a reinforcing corrugation 30 in the web as shown in FIGS. 1-6, this corrugation may be utilized as the passageway by welding a metal sheet or plate 31 across the open rear side thereof. A plurality of jets 32 are formed in the underside of the corrugation 30, being disposed toward the slots 12 as best shown in FIG. 6, in order to direct a blast of air toward the slots. One end of the passageway thus formed may be closed as indicated at 30 in FIG. 1 and a source of compressed air may be connected to the other end thereof.

The modification shown in FIG. 7 differs from that above described only in that the dust ledge 7 is substantially horizontal instead of being downwardly and outwardly inclined.

In FIG. 8 is shown a further modification in which there is no dust ledge. All other parts are indicated by the same reference numerals as in FIGS. 6 and 7.

In FIG. 9 is shown another modification in which the air passage is formed by an angle member 33 welded upon the web 9 to form an air passage. A plurality of jets 34 are formed in the underside of the air passage thus provided and disposed toward the slots 12 in order to direct an air blast therethroug h.

In FIG. is shown another slight modification of skewback channel in which a pipe 35, with jets 36 therein, is welded upon the web 9 just above the slots 12.

In the modification of FIG. 11 there is no dust ledge and a pipe 35, with jets 36 therein, is welded to the web 9 directly above the slots 12.

A self-cleaning roof construction is thus provided which prevents accumulation of fly ash, dust and dirt in the pockets formed by the webs of the skewback channel at opposite sides of the furnace roof and ordinarily interfering with the uniform operation of the furnace.

From the above it will he obvious that the novel form of skewback channel and charging door frame provides means for easily and readily cleaning the furnace roof and preventing accumulation of fly ash, dust or other dirt in the pockets formed by opposite sides of roof and the adjacent skewback channels.

It will also be seen that the dust and dirt removal through the slots 12 is positively aided by means of the auxiliary air passages such as the closed-in corrugations 30 (FIGS. 6, 7 and 8), or angles 33 Welded to web 9 (FIG. 9) or pipe 35 (FIGS. 10 and 11). These various forms of cleaning media passageways carry pressurized air or other media which is discharged from the openings or jets in the underside thereof in a blast directed toward the slots 12.

Thus positive motivation is given to dust and dirt in its passage over the dust shelf (if used) and through the slots, insuring a positive cleaning action of this critical area and minimizing the possibility of any accumulation between the ends of the roof arch and the water-cooled skewback channels.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by Way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful constructions, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. In a furnace of the open-hearth type having an arched roof, skewback channels at opposite ends of the arched roof, each skewback channel having a skew surface supporting the adjacent end of the arched roof and terminating at its upper end at substantially the adjacent portion of the top of the arched roof, and an upwardly extending web upon said skewback channel, the improvement comprising a plurality of horizontal slots in said web, the lower edges of said slots being substantially flush with the adjacent top edge of the roof, a horizontal passageway upon said web above the slots, there being jets in the underside of the passageway directed toward said slots, and means for passing a pressurized media such as compressed air through said passageway.

2. The improvement as defined in claim 1 in which there is a dust shelf on the skewback channel between the adjacent top edge of the roof and the lower edges of said slots.

3. The improvement as defined in claim 2 in which the dust shelf is substantially horizontal.

4. The improvement as defined in claim 2 in which the dust shelf is outwardly and downwardly inclined.

5. The improvement as defined in claim 1 in which the passageway comprises a closed-in corrugation in the web.

6. The improvement as defined in claim 1 in which the passageway comprises an angle member welded to the we 7. The improvement as defined in claim 1 in which the passageway comprises a pipe welded to the web.

8. The improvement as defined in claim 1 in which a charging door frame is located at the outer side of one of the skewback channels, said charging door frame including an upper water chamber and depending legs, the top of said upper water chamber terminating slightly helow the lower edges of said slots.

9. The improvement as defined in claim 8 in which the top of the upper water chamber is inclined outwardly and downwardly.

10. The improvement as defined in claim 8 in which there are upwardly disposed extensions at the side edges of the door frame, said extensions being vertically aligned with the depending legs, and a channel bracket connected to the upper ends of said extensions.

7 8 11. The improvement as defined in claim 1 in which References Cited the lower edges of the slots are taper-cut in a downwardly UNITED STATES PATENTS and outwardly inclined surface corresponding with the 2 919 683 1/1960 Reighart 122 6 s1Pe of the adlacem 310321327 5/1962 McLain III 263 44 12. The improvement as defined in claim 10 in which 5 there is a Water inlet into the top of one extension, the CHARLES MYHRE, Prlmary Examinerlower end of said one extension being closed except for a U s C1, X R water outlet to the upper water chamber. 122 499; 263 44

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