US1628284A - Furnace-arch construction - Google Patents

Description

May 1927' N. 0. STEVENS ET AL FURNACE ARCH CONSTRUCTION Filed WLQJE L.

1,628,284 May 10 1927' N. D. STEVENS ET AL FURNACE ARCH CONSTRUCTION Filed Nov'. 9. 1920 2 Sheets-Sheet 2 Patented- May 10, 1927.

UNITED STATES PATENT OFFICE.

NATEANIELDi STEVENS, 0F HAZIJETON, PENNSYLVANIA, AND LOUIS H. HOSIBEIN, 0]!

cnrcneo, ILLINOIS, AssmnoBs 'ro' NOIS, A. CORPORATION or nmmors.

1 L DETRICK COMPANY, OF CHICAGO, ILLI- IUBNAOE-ARCH CONSTRUCTION.

Application filed November 8, 1820. Serial No. 422,775.

This invention relates generally to furnace arch construction, and incertain features pertains particularly .to ignition archconstructions especially adapted for use in furnaces equipped with over-feed or traveling grate stokers.

A general object of the invention is the provision of a furnace arch construction which is particularly qualified to withstand the destructive influences to which such structures are subjected in use, and which, when employed in ignition arches,is adapted to contribute effectively to early ignition of fresh fuel and to the promotion of combustion within the furnace.

Another object is the provisionof an arch construction which effectively fulfills the re- I quirements'mentioned and which is adapted to l to be installed with facility and admit of repair, particularly with respect to the renewal or replacement of the refractories, with convenience and without requiring extensive dismantling of associated parts.

Still another object of the invention isthe provision of an arch construction possessingthe characteristics above mentioned and which may be installed in furnaces not designed particularly therefor, and which may be supported without depending upon the furnace walls as the load carrying memers.

p Yet-another object is the provision of an arch'construction particularly adapted for the'support of anapron wall in association 3 ,th'erewithan'd in such fashion that the shifting of the arch refractories incident to ex pansion or contraction of the structure from 'temperature changes will not displace the wall or open up joints between it and the, associated arch portions.

Yet another object is the provision of construction by virtue of which the arch and the associated apron wall may be sup ported in association with other parts of the structure, such as a movable gate for controlling the feed of fuel, without hampering or imposing limitations on the operation or adjustment of such associated parts.

'Yet another object of the invention is the provision of an improved element of furnace arch construction, in the nature of a specially formed refractory ortile having features which rnder posiible the construction of anarch of advantageous form and.

flexibility.

Other and further objects and advantages in the ar In the drawings:

Fig. 1 is a longitudinal vertical section through a portion of a chain grate stoker furnace equlpped-with an ignition arch construction in which our invention is embodied;

Fig. 2 is a transverse vertical section 0 the furnace, as on line 22 of Fig. 1, show-- ing the roof arch in section and the ignition arch in elevation with certain intermediate portions removed; I Fig. 3 is a perspective view of one of the brick supporting structures and-its suspension plate; I

, Fig. 4 is a transverse sec-tionvof said brick supporting structure, as on line 4-4 of Fig.

Figs. 5 and 6 are perspective views of special wedged shaped refractories or tile constituting subject matter of our invention.

As is well known in the art, in various types of over-feed stoliers and the so-called chain-grate stokers, fuel is fed to the fuel bed in such fashion that it comes into the, furnace at the marginal portion thereof.

This fresh fuel, of course. is cool, and before it will ignite, its temperature must be raised to the ignition point. Efficient operation deminds that this be accomplished as quickly as possible. Ignition arches have been con 'structed in various fashions for the purpose of attaining this result. One of theimpor tant advantages made possible by the present invention resides in the fact that by our improvedconstruction, not only is the ignition of the fresh fuel attained efiicie y and quickly, but also the combustion efliciency of the furnace is increased and the arch is effectively safe-guarded against too rapid disintegration from the normal condition existing within the furnace. We accomplished these results by the provision of a construction which renders it practicable to bring the forward extremity of the ignition arch down to a point quite close to the surface of the fuel bed where the fresh fuel is fed thereto, while positioning the portion of the arch above the ignited portions of the fuel bed at such a distance therefrom and in such a relationship thereto as to avoid, to an ad vantageous extent, the destructive influences of the heat and the products of combustion from the burning fuel. At the same time, the construction permits the reduction of cold space within the furnace without limiting the combustion space desirable for the complete combustion of the volatiles or suspended constituents in the combustion gases, and accommodates a maximum reflection of radiant heat onto the entering fuel below the ignition arch. The invention is not limited for its advantages to employment in ignition arches, however, as it possesses certain structural features which contribute a desirable flexibility in portion of refractory arch structure where the arch changes direction, maintaining close joints between the component refractories and affordinguniform protection for the metallic members whereby they are supper ted.

Referring to the particular example illus trated in the drawings, let it be understood that the numeral 10 designates the side walls of the furnace, and 11 the fuel hopper which tance above the chain grate to afford the desiredvolume within the combustion chamber to permit the proper admixture of air with the volatiles given off from the fuel and promote combustion thereof. The numeral 14 designates generally the ignition arch which is located at the front of the furnace with its lower end adjacent the fuel inlet and in association with the fuel gate. This ignition arch is carried on a plurality of brick supporting frames, preferably of cast-iron. which are arranged in collateral relationship across the front ofthe combustion chamber. Each of these frames is suspended by means of a suspension plate 14 from a girder or beam 1 which extends transversely across the forward portion of the combustion chamber, being supported either on theside wall 10 or on other sup.- porting members. Each of these frames in the form here shown, comprises a webbed body portion having an upper horizontally flanged portion 17, a vertical front portion 18, and a curved or convex rear portion 19.

The convex portion 19 is provided at its rearward margin with laterally extending flanges 20 which take the arcuate form of the portion 19, and from the lower end of these flanges depends a stop member 21. The front vertical portion 18 is provided on each side thereof with spaced vertical flanges 22, which terminate at their lower ends in a horizontal flange 23. Suspended on the arcuate flanges 20 of each of the frame members, is a series of wedge shaped refractories 24, which are formed with the T-shaped slots 25 approximately at the middle portion of their narrower ends, said slots receiving the flanges 20 and a portion of the web 19, so that -the refractories are retained thereon with a limited freedom of individual movement. It will be observed that these wedge shaped refractories 24 are of a form wherein the broader end face extends at approximately a rigl'it angle from one of the converging faces,'so that the opposite converging face meets the broader end face at an acute angle. By virtue of this form of the wedge shaped refractories, they may be arranged so as to Vary the curvature of the arch surface which is formed by their broader end faces. The refractories 24 are slipped on to the flanges 20 at the upper end of the latter, the first refractory applied being slid downinto contact with the stop member 21, and the succeeding refractories being slipped down into abutting contact with one another in series. The lateral faces of the refractories on adjacent frame members make contact, so that when all are assembled the structure provides a convex refractory arch extending across the front of the furnace chamber and terminating at its lower end adjacent the fuel gate and close to the fuel inlet. By the assembly of the wedge shaped refractories in the manner illustrated, the uppermost one presents its upper face in a substantially horizontal disposal at some distance below the roof arch 13. The intervening space is filled by an apron wall built up of refractories 26, which aresupported on the uppermost wedge shaped refractories 24, and the joint between the top of this apron wall and the roof arch is filled with a suitable refractory joint material. It will be observed that on each of the frame members, the web shaped refractories 24 as well as the apron wall refractories 26 are supported in position by the stop member 21, which prevents the lowermost refractories 24 from being displaced forwardly, thereby safeguarding the adjustable fuel gate from pressure from this depending arch does wedge shaped tile are constructed,

It will be observed that the construction provides a refractory arch inwhich each of the component refractories has but a smgle face exposed to the fire .within the combus-y tion chamber, which face is {ofrelatively limited area. By virtue of this feature, the destructive influences of the high Jfurnace heat and the p and slag are minimized, with the result that the arch does not wear out so rapidly and the Wear is more uniform over its surface and not so likely to ,be localized. :Thus, not 1 only is the life of the arch as a whole increased; but the likelihood of having to shut down the furnace for repair of a badly worn spot is substantially reduced. I When embodied in an ignition arch, this construction provides a refractory heat reflecting wall with a heat resisting and reflecting surface close to the entering fuel and arranged'to direct reflected heat on to it. At the same time, not overhang the fuel bed in such fashion as.to bafile or mask the reflection of heat from the top arch on to the entering fuel, but tends to aid in the c011- centration of heat on the fuel bed immediately'inside the fuel inlet. This is of particular importance in instances where it is desirable that the ignition arch extend for a substantial. distance into the upper portion of the front of the combustion chamber, where it exercises an important function in reducing the space over the fuel inlet, which" otherwise would be relatively cold and thus hinder the quick ignition of the entering fuel. By virtue ofthe manner in which the I they are susceptible of a limited freedom of movement relative to one another both laterally, forwardly, backwardly and outwardly, the engagement of the tile with frames permitting them individually a certain extent of rocking movement in those directions. This assures a close fit between the tile at all times and permits them to accommodate themselves to expansion and contraction of the structure resulting from temperature changes, without imposing injurious lsgtrcsses on them or on the supporting memers. Between the flanges 22 of juxtaposed frame members are slid tiers of brick 29, which find support on the horizontal flanges 23. These tiers of brick form a vertical front wall which prevents coal from the coal hopper being pushed backon to the outer ends of the refractories 24, and maintains an open space for-the circulation of air over the outer ends of those refractories and the frame members. This is of distinct imporerosion from the furnace gases the supporting When'it becomesnecessary to replace any of the refractories, the apron wall refractories 26 are/first removed, afterwhich the wedge shaped refractories may be moved upwardly on the flanges 20 and disengaged therefrom at the upper end. Thus replacement of refractories onany of-the frame members maybe made'without the necessity for dismantling refractories. from associated frame membe As the arch expands or contracts longi tudinally incident to temperature changes, the aggregate movement resultingtherefrom is imparted to theapron wall in a vertical direction without relative displacement of the wall and the arch refractories which support it. Consequently, expansion or contraction of the arch does not have the effect of displacing the apron wall into the furvnace, or of dislocating-its support or of opening the joint between the arch and wall.

We claim: 1. In a furnace having a fuel inlet at a margin of the grate, an ignition arch arranged above the margin of the grate at which fuel is introduced, said ignition arch comprising a series of spaced-apart depending frame members having a convex inner PQItlOIlLI'lSlDg abruptly from the lower end,

such convex portion having a laterally projectingfflange for a part of its length, and a series of wedge-shaped bricks having in their smaller ends recesses accommodating the said flange to sustain said bricks in abutment with one another.

2. In a furnace having a grate, an ignition arch arranged above the portion of the grate at the fuel inlet, said ignition arch comprising a series of .frames each having a convex inner portion rising abruptly from its lower portion, such convex portion having a succession of angularly related longitudinal flanges, and series of wedge-shaped bricks having in their smaller ends recesses accommodating the said flanges to sustain said bricks in abutment one with another.

3. In a furnace having a grate and a main arch overhanging the grate. an ignition arch arranged above the margin of the grate at which fuel is introduced, said ignition arch comprising a series of laterally associated frames each having a convex inner portion rising abruptly from its lower end toward the mainarch, and having also a "ertical front portion, such convex and vertical portions having marginal flanges, series of wedge-shaped bricks having in their smaller ends recesses accommodating the flanges of the convex portion and disposed in close lateral relationship, and a series of bricks sustained by the flanges of the vertical portion.

4. In a furnace having a grate and a main arch overhanging the grate, an ignition arch arranged above the portion of the grate atwhich fuel is introduced, said ignition arch comprising a girder arranged at a margin of the main arch, a series of laterally associated frames secured to and depending from said girder, each of said frames having a convex inner portion rising abruptly from its lower end toward the main arch, and having also a front vertical portion, such convex and vertical portions having marginal flanges, a series of wedge-shaped bricks supported by said convex portions and arranged in close lateral relation to one another, a series of bricks imposed on said wedge-shaped bricks and built up to the main arch, and a series of bricks retained by the flanges of the vertical portion.

5. In a furnace, an ignition arch comprising a plurality of frames having their lower extremities disposed adjacent the fuel inlet and each including a tile supporting portion extending inwardly and upwardly from its lower extremity, said tile supporting portion carrying tile retaining members, and wedge-shaped tile connected at their smaller ends with said retaining members to retain juxtaposed tile with their converging faces in abutment, the larger end surfaces of said tile forming a fire resisting wall extending first inwardlynnd then abruptly upwardly from the fuel inlet.

(3. In a furnace arch construction, the combination of a plurality of collaterally disposed frame members, each including an inwardly and upwardly extending arch supporting portion and an upwardly extending I wall supporting portion, and brick retained in associa ion by said respectiveportions to constitute a wall portion and an arch portion of the furnace.

7. In a furnace, an ignition arch comprising a plurality of collaterally disposed frame members having their lower extremities disposed adjacent and above the fuel inlet, each of said frame members including an inwardly and upwardly extending part carrying tile retaining members, a plurality of wedge shaped tile engaged at their narrower ends with said retaining members, the tile on each frame member being disposed with the converging faces of juxtaposed tile in abutment whereby the exposed end faces of the tile form a substantially regular convex arch surface extending inwardly and upwardly from the fuel inlet.

8. As an article of manufacture, a furnace archportion consisting of refractory tile having parallel lateral faces and converging front and rear faces all of substantially said arch, and a convex arcuate ignition arch made up of refractory tile suspended from said beam at the front of the tire box chamber, each of said tile presenting but a single face \vithin'the combustion chamber.

10. In a furnace. a roof arch, a transverse suspension beam arranged in front of said arch, a convex arcuate ignition arch suspendedfrom said beam at the front of the furnace chamber, and an apron wall resting on the ignition arch and extending between the same and the roofarch to form the up per portion of the front of the furnace chamber. r

11. In a furnace, a roof arch having a series of transverse suspension beams overlying the arch refra-ctories and supporting the same, atransverse suspension beam ar ranged in front of said roof arch, and a convex arcuate ignition arch suspended from said beam at the front of the furnace chamber, said ignition arch curving inwardly and abruptly upwardly from the fuel inlet to accommodate the reflection of heat from the roof arch onto entering fuel.

12. In a combustion furnace having a vertically extending wall portion, an arch construction including a substantially horizontally extending refractory roof arch portion, a plurality of refractories supported adjacent the vertical wall portion to form an inwardly and upwardly extending refractory arch portion below the roof arch portion, and a plurality of vertically associated refractories supported upon the inwardly and upwardly extending arch portion and forming avertically extending wall closing the space between the same and the roof arch portion.

13. In a furnace. an arch -construction comprising a suspension beam, a metallic frame member secured thereto and depending below the same. and :1 tier of wedgeshaped refractory bricks slotted to straddle said frame member, and secured thereto.

H. In furnace construction, the combination with a substantially .verti'al \vall portion and a substantially horizontal refractory arch portion. of a plurality of tile supporting members disposed adjacent said portions, and a plurality of wedge-shaped refractories supported on said members with their lateral. faces in contact and with their broader end faces forming a convex arcuate fun IlL I vided with a slot extending from front to r of the furnace rear for accommodation of the frame member, said tile being provided adjacent said slot with a depression in one of its converging sides for accommodation of the stop flange of the frame member.

' 16. In furnace arch construction, the combination of a beam disposed above a portion chamber, collaterally arranged frame members depending from the beam, wedge-shaped tile suspended from said frame members with their broader ends toward the furnace chamber and their lateral faces juxtaposed, to form an upwardly deflected convex refractory arch portion, refractories supported on the upper tile to form a vertical wall portion as an upward continuation from said convex portion, and

stop members on said frame members con-v tacting the lower terminal wedge-shaped tile. 7

17 As an article of manufacture, a structural element for furnace arches, consisting of a wedge-shaped tile of refractory material having parallel lateral sides and converging front and back sides, said tile being provided at the narrower end with a medial -shaped slot opening at the converging sides and across the topto provide oppositely overhanging shoulders whereby the tile may be supported with its front and back sides in contact with those of similar tile.

18. As an article of manufacture, a structural element for furnace arches, consisting of a wedge-shaped refractory tile having parallel lateral sides and converging front and rear sides, and a broader end face meeting one of. said last mentioned sides at approximately right angles, said tile being provided in its narrower end with a medial inverted T-shaped slot opening at the front and back sides. I

19. In furnace construction, the combination of frame members collaterally disposed along a side of the furnace chamber, an upright wall portion supported on said frame members, and a convex refractory arch portion supported on said frame members extending nwardly and upwardly between said wall portion and the combustion cham- 20. In furnace construction, the combination of frame members disposed collaterally along a side of the furnace chamber, a convex refractory arch formed of refractories retained by said frame members, and an upright wall portion built .upon said arch portion with its inner surface arranged as a continuation from the arcuate surface of the arch.

21. A frame member for .furnace arch construction comprising a casting having a web portion with an arcuate tile supporting flange extending at an angle therefrom and provided at an upper margin with means for engagement by a supporting member, whereby the casting may be suspended from the top with the arc of the flangein a vertical plane. 1

22. In furnace construction, collaterally arranged frame members, wedge sha ed tile suspended thereon with their broa er end surfaces exposed within the furnace chamber and their narrower end surfaces exposed outside the furnace chamber, and a wall spaced from the outside ends of the refractories to afford an intervening air duct for circulation of air across said ends of the reg fractorles.

cured thereto, the wider end surfaces of said wedge shapedbricks forming a convex arch portion within the furnace chamber.

24. In a chain grate furnace, the combination witha roof arch over the combustion chamber, of a convex ignition arch suspended at the front of the roof arch and presenting a refractory surface curving inwardly and upwardly from the fuel inlet to accommodate and concentrateheat reflected from the roof arch onto fuel on the grate at the fuel inlet.

NATHANIEL 'D. STEVENS. LOUIS H. HOSBEIN.

DISCLAIMEZR 1,628,284.Nathaniel D. Stevens, Hazleton, Pa, and Louis H. Hosbein, Chicago, Ill FURNACE-ARCH CONSTRUCTION. Patent dated May 10, 1927. Disclaimer filed November 1, 1935, by the assignee, M. H. Det'm'ck Company.

Hereby enters this disclaimer to that part of the claim in said specification which is in the following words to wit:

5. In a furnace, an ignition arch comprising a plurality of frames having their lower extremities disposed adjacent the fuel inlet and each including a tile supporting portion extending inwardly and upwardly from its lower extremity, said tile supporting portion carrying tile retaining members, and wedge-shaped tile connected at their smaller ends with said retaining members to retain juxtaposed tile with their converging faces in abutment, thev larger end surfaces of said tile forming a fire resisting wall extending first inwardly and then abruptly upwardly from the fuel in et.

7. In a furnace, an ignition arch comprising a plurality of collaterally disposed frame members having their lower extremities disposed adjacent and above the fuel inlet, each of said frame members including an inwardly and upwardly extending part carrying tile'retaining members, a plurality of wedge-shaped tile engaged at their narrower ends with said retaining members, the tile on each frame member being disposed with the converging faces of juxtaposed tile in abutment whereby the exposed end faces of the tile form a substantially regular convex arch surface extending inwardly and upwardly from the fuel inlet.

In a furnace, a fire box arch, a transverse suspension beam arranged in front of said arch, and a convex arcuate ignition arch made up of refractory tile suspended from said beam at the front of the fire box chamber, each of said tile presenting but a single face within the combustion chamber.

22. In furnace construction, collaterally arranged frame members, wedgeshaped tile suspended thereon with their broader end surfaces exposed within the furnace chamber and their narrower end surfaces exposed outside the furnace chamber, and a wall spaced from the outside ends of the refractories toafford an intervening air duct for circulation of air across said ends of the refractories.

24. In a chain grate furnace, the combination with a roof arch over the combustion chamber, of a convex ignition arch suspended at the front of the roof arch and presenting a refractory surface curving inwardly and upwardly from. the fuel inlet to accommodate and concentrate heat reflected from the roof arch onto fuel on the grate at the fuel inlet.

[Oflicial Gazette November 26, 1985.]

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