US2676793A

US2676793A - Open hearth furnace

Info

Publication number: US2676793A
Application number: US173076A
Authority: US
Inventors: Jones Herbert
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-07-11
Filing date: 1950-07-11
Publication date: 1954-04-27
Anticipated expiration: 1971-04-27

Description

April 27, 1954 H. JONES 2,676,793

OPEN HEARTH FURNACE Filed July 1l, 1950 5 Sheets-Sheet l April 27, 1954 H, JONES 2,676,793

OPEN HEARTH FURNACE y Filed July 11, 1950 y 3 Sheets- Sheet 2 FIGZ.

sa 54a 54 2a April 27, 1954 H. JONES4 OPEN HEARTH FURNACE 3 Sheets-Sheet 3 Filed July 11, 1950 I I I l l I l I l Illlllllll Patented Apr. 27, 1954 UNITED STATES PATEN T OFFICE' OPEN HEARTH FURNACEA Herbert Jones, Milford, near'Derby, England Application July 11, 1950, Serial No. 173,076

3 Claims. 1.1

Thisinventionhas referenceto open hearth furnaces.

When such furnaces are `in operation, hot vwaste gaseous products in whichv'particles of foreign matter are suspended, flow at high velocity from an end of the hearth Vinto a slag pocket which extends below the latterand downwhichthe said products and, particles are` caused vto pass. Asa consequence, the products and suspended particles are caused to.Y make a` considerable change, of approximately-'90", in their direction of travel and,Y in making: this change, they `impact on the correspondingY end-wall. of the furnace with considerableforce. The condition of the end wall therefore deteriorates-rapidly and necessitates repairs ybeing carried out at frequent intervas.

It will bel appreciatedthat before an end wall of the furnacecanbe demolished, or partly demolished,V by manual labour, it is necessary to shut down the furnace and allow it to cool down to a considerable extent.-

The principal 'object of the present-invention isto'minimise the period duringY which an open hearth furnace need be shut down when an end wall becomes defective;

A further principal object of the invention' is to enable that section'cf an end wall of an open hearth furnace which deteriorates the most rapidly when the furnace is in use, to be removably assembled in the 'furnacefstructure Another object of the invention is to ensure that a removable section of gan open hearth furnace end wall can' beremoved-and replaced by an identical portion ina minimum of time- Still another object of the invention is to ensure that a removable section oi an open hearth furnace end wall can nlne-accurately.4 and quickly aligned withthexed structure upon-being as.- sembled to the furnace.. v

Yet another object ofthe invention is to ensure that -a removable section ofan open hearth furnace end wallr is sealed Atothe fixed structure in a gas tight manner. n

Another object ofthe invention is .to enable a removable end wall sectioncofuan open hearth furnace to be bodily assembled to the fixed. structure and dismantled Yfrom. the said structure without damage.

With these andother objects in view, which will become apparent as this"specfi'cation proceeds, the construction 'ofan end-Wall of an'open hearth furnace will now be: describedI with reference-to theaccompanying drawings which illuse trate` a 'preferredeembodiment'fof fthe invention;

' Inl-thefdrawingsai i' Figure 1 is a sectional'elevation of .theupper removable sectionof an endl Wallof an` open hearth furnace. 1

Figure2 is a section` taken alongl .theline-2-2,VV Figure 1.

Figure 3 is an elevation, on a smallerscale; showing the skeleton` metal framework` ci they removable wall section shown inv Figures 1 vand\-2, and the metal framework-of the--adj0ining-pcr tion of the fixed `furnace structure;I

Figure Ll-is an enlargedsca-le elevationand- Figure 5 is a sectionalplan showingsmeans for securing the upper end of the removable endwall section to the xed furnacefstructure.

In the embodiment Y of'fthe*inventionshown 4in the drawings, an Yopen hearth =furnace+comprises aixedv back'wall part of-which is-1shown-at vI (Figure 1), aY fixedv frontwall partof Whichfis shown at 2 (Figure 2), a iixeolrroof or arch'fpart of which is shown' at-'S (Figure 1), an'd-two1xedf end 'walls 'a part of'v oneof-"which 'isshown'l'ati d (Figure 1) each -xedendA wall beingass'ociated with an upper and removable wall Asection 5. A

EachA end `wall v4l serves "aslone-wall iof faslag pocket 'or pit SWhchfis provided in?"thefcorre`v sponding endv ofV the'furnace'outwardly1-' offf thiehearth (not shown?) "and `below 'hearthUlevelr` the said pocket or pit receives thehot wastegase'ous products and' particles.' of" soli'dforeignmatter suspended therein, .discharged 'horizontallyffom the hearth at a high'velocity whenthe'furace is in operation.' The 'th'ro'atof'the"saidpeket or pit isfdefined partiallyfbyinclinedf'endwall- '5a' of the removable section 5 and the inclinationof the said Wall'a assists in' changinglthewl-of y the saidv gases from the horizontal-path along v intoaverf" tical or. substantially" vertical path* downwardly of the said thro'atandinto .the"said-"pocket(irlpit.'y

The removable sectibn alsoin'clude's afback wall which they travel from? the hearth,

la anda front wall- Zdwhich'are located-inthe planes ofthe backend-*front walls'l `'an'dDZ're spectively of the furnace structurel! Thus;-4 in# elevation, the removablesection is-'of ash ape4 somewhat resembling" a right-angled :triangle of which the wall'a'formsthe hypotenuse'. How# ever, as shownin Figure'l, the'wall tris not straight but is forme-dr at 'orvin' the'regionofits lower edge with a' convex portionj 5b so that'thel face of the Vsaicl edge is horizontallydisposed'and" is at right angles to the inner face 'of the iixed'end" wall 4; also, at or in'theregion of its fupii'er'"edge,A

the wall tais formed with aconv'e'xporti'n 5 sov that thefupper 'extremity' ofV its' 'inner' face" isf? vertical and is`-'adaptedtomate withand sitiiat' upon th'eadjacentend adge of thearch or roof '3f The removable section is carried by and within a skeleton metal framework which comprises, :forwardly and rearwardly of the front and back walls 2a, la, a system of upright buckstays l, of boX-like or double-channel cross-section, and, endwardly of the inclined wall 5a, a system of H-section girders 8 of which the upper and lower ends are swept or curved to conform to the shape of the upper and lower portions of the said wall 5a.

The buckstays 'l are of successively diminishing height (see Figure 3) from the edges of the section 5 which are adjacent the back and front walls l and 2 of the xed structure, to the girders the buckstays 'l are interconnected and braced by varying numbers of superimposed and spaced horizontal tie-bars 9. The feet of all the said buckstays on the front of the removable section are secured to and internally of a horizontal channel-section beam H and the buckstays at the rear of the section are similarly secured to an identical beam. The beams li seat upon the upper edges of the xed back and front walls of the pocket or pit 6 and each is provided with a hole or socket l2 through which extends a complementary spigot on dowel pin i3 provided on the said fixed wall edges.

The upper end of the longest buckstay 1, at the front and rear of the removable unit, is provided with an angle claw i5'.- which extends towards vertical buckstays i5 incorporated in the skeleton framework of the fixed furnace structure. The claw consists of one arm which is fixed to the said longest buckstay and a second arm 14a which projects outwardly of and is arranged at right angles to, the said longest buckstay; the said arm Illa engages (as shown most clearly in Figures 4 and 5) behind a complementary claw I6 iixed to the adjacent buckstay i5 and having an upper edge which is inclined upwardly and away from the said adjacent buckstay; hence, the engagement of the claw arm ida with the ixed claw I6 forces the upper end of the removable section towards the fixed furnace structure and takes the vertical inner surface of the upper wall portion 5c into close abutting contact with a facing plate i1 (Figure l) on the corresponding end edge of the arch or roof 3.

The girders 8 are arranged in spaced parallel relationship across the removable section and are interconnected at their inner edges (that is, the edges adjacent the wall 5a) by straight and horizontal spaced I-beams I8.

Adjacent each end of, and at right angles to,

the said -beams i8, and on the inner side thereof, there is fixed a channel section beam iS (Figure 2) which is of the same shape, in elevation, as the girders 8. The sides or flanges of each beam I9 respectively embrace the adjacent end edges of the back wall la and front wall 2c of the removable section thereby providing -a positive key between the end wall 5a and the said back and front walls.

rIhe two end girders 8a of the removable section 5, are of box-like or double channel Vsection (see Figure 2) and each has an eyed bracket 25 secured in its upper extremity. Outwardly of the said girder ends, an upright 2i is xed by its foot to the corresponding girder 8a, the said upright also being of box-like or double channel section and having an eyed bracket 22 secured in its upper extremity. The upper end of each girder 8a is braced to the corresponding upright 2! and to the upper extremity `of the wall 5a, by horizontal I-beams 23 and 24 respectively. The

eyed brackets 2D, 22 serve as anchorages for engagement by lifting tackle, such as -hooks on the end of a crane cable.

The feet of the girders B, 8a are secured to and internally of a horizontal channel-section beam 25 which is located in spaced and parallel relationship to the lower edge of the wall 5a and is adapted to seat upon a plate 2t carried upon transverse I-beams 21 incorporated in the upper edge of the xed end wall :'i. A spigot or dowel pin 28 provided on the said plate 25 projects through a hole or socket 2S formed in the beam 25. The engagement of the holes or sockets i2 and 29 in the horizontal beams l l and 25 respectively, by the complementary spigots i3 and 23 on the upper edges of the fixed wall portions i, 2 and 4 of the furnace structure ensures that the removable section 5 is positioned correctly in relation to the fixed structure and also that cne or more burners (not shown) located in the plane r (Figure 1) and carried by the said section is or are disposed in their predetermined correct relationship tothe furnace hearth.

The two box or double-channel sectioned end girders 8c are located respectively in the planes of the buckstays l at the front and back of the removable section 5. The removable section is reinforced by laterally inclined beams til which are located in a horizontal plane and are secured to and between the channel beams ii and extensions 25a of the channel beams 25, and by inclined beams lll which are located in vertical planes and are secured to the said buckstays i and end girders 8a; the upper ends of all but the tallest buckstays 'l are also secured to the said end girders (see Figure 3). An l-beam 5i extends alongside and is coextensive with the channel beam 25 and is xed to the outer edge of the feet of girders 8 and dos by webbed angle brackets 52.

As a consequence, the entire skeleton framework of the removable section 5 is made strong and inherently rigid and can therefore be lifted into and out of position on the fixed structure 'without danger of temporary distortions or deflections capable oi damaging the brickwork of the walls ia, 2a and 5a built into the said framework.

The said brickwork includes, in a known manner, bricks or blocks 53 and 5d having tapered and outwardly projecting heads 53d, 5ta ure 2). Each tapered brick head is held by a jawed plate 55 which is anchored to the said skeleton framework of the removable section in a manner which permits limited relative movement of the said brickwork due to expansions and contractions thereof as its temperature varies from time to time. For this purpose, the crown of each jawed plate is provided with a hooked rod 56 which engages a hooked rod 5l rigidly secured to the framework. The rods 5l' which assist in the anchorage of the walls la, 2a to the framework, extend through and are bolted to the buckstays 1, whereas the rods 5l which assist in the anchorage of the wall 5a, are bolted to the adjacent sides or flanges of the horizontal channel beams i8. In addition, the weight of the walls la, 2a is carried by a system of horizontal plates 53 which are inserted into certain of the courses of the bricks or blocks from the outside of the brickwork, the external ends of the said plates being formed with jaws which engage the edges of the tie-bars 9. Similar jawed plates 59 (Figure l) engaging the edges of corresponding horizontal beams I8, are/inserted intor'cera tainf-of'thefcourses of the-end wall 5a.

A lflange-or lip--60 -(Figure '2)' is' provided along and'projectsiinwardly fromeach of the tallest buckstaysfl into overlapping relationship to the edge of-thecorresponding-*wall 'lla or 2a; the said flangefonlip entersand is secured in a'recess formed in the. edgeofthe corresponding wall which is adjacent the iixedwallsl and 2 of the furnaoe structure.

The ties effected yby the hooked rods 5S, al, and by the flanges ,or"v lips Si) ensure that the brickwork of the removable section .is securely anchored to the skeleton framework-.of the struc-v ture.

To ensure that gas-tight seals are effected between the removable section and the fixed furnace structure, sand seals are provided between the upper end of the wall tia and the roof or arch 3, and between the lower ends of walls Ea, 2a and 5a and the fixed walls l, 2 and 4. Thus, as shown in Figure 1, a sand trough 6I is provided along the outside of the roof or arch 3 and, as the section 5 is lowered into position, the free edge of an inverted channel section flange S2 (which is fixed to section 5) enters the said trough and becomes embedded in sand in the trough. Similarly, a sand trough 63 is provided along the upper edge of the fixed end wall 4 and a lip B4 which depends from a plate 65 carried on the underside of a horizontal bar 65 spanning the inner edges of the girders 8, 8a, enters the said trough 63; troughs (not shown) identical to the trough 63 are provided on the back wall l and front wall 2 of the fixed structure for receiving depending lips of plates (also not shown) Y spanning the feet of each system of buckstays '1.

When the removable section 5 is in its assembled position, a clearance exists between the removable back wall portion la and the removable front wall portion 2a, and this clearance is filled A in with bricks 61 (Figure 2) in a manner which enables the said bricks to be readily and quickly removed.

When the furnace is in operation, the particleladen hot gaseous waste products discharged from the hearth impinge upon the brickwork of the removable section 5 at considerable velocity;

as a consequence the condition of the said brickwork deteriorates much more quickly than the brickwork of the fixed structure; when replacement becomes necessary, bricks 61 are knocked out and the said section 5 is lifted bodily from the furnace and is replaced by a new or re-built section. The replacement is effected quickly and without difficulty, since there are no bolted or similar connections to make and break; further, the exchange may be effected without having to wait for the furnace to cool down to any considerable extent. When a defective unit has been removed, it may be repaired at leisure for re-assembly in the furnace as and when required. Consequently, it will be appreciated that the invention enables the defective end wall of an open hearth furnace to be put in working order in a minimum of time thereby considerably reducing the total period during which the furnace has to be shut down for this purpose.

It is to be understoodthat the invention is not restricted to the specific embodiment described and shown and that anychange of the construction shown may. be made within the scope of the following claims and without departure from the scope of this invention.

I claimt l.. Inf anv open hearthl furnacehaving anrendof Whichtherupper portionK is1-removab1e,wthe said endportionbeing builtfwithin and supported'v by arigid skeleton frameworkcomprsing systems of buckstays and igirlders,4 thessaid .framework and.

endl portion fforming. an- `assembly separate ,from the.stationaryl furnace f structure, lifting brackets incorporated in and externallylofthe saidrframework, interrengaging:` Spigots. and sockets. on the lower edge ofthe framework andthe upper edge of the stationaryfurnace structure 'which receives the saidj.' framework, and: inter-engaging` claws fixed on :the: upperforwardazedge. of the ,framework andftheadjaoent edgerzof; the stationary furnace structure, the said spigots, sockets and claws automatically locating the framework and end portion assembly in position relatively to the stationary structure when brought into engagement.

2. A unitary liftable `wall member for an open hearth furnace, including a portion which is substantially vertical and is adapted to be aligned with and temporarily joined to the back wall of the furnace, another portion which is substantially vertical and is adapted to be aligned with and temporarily joined to the front wall of the furnace, a third portion which joins the other.

two portions and is inclined to the vertical and has its upper end adjacent the roof of the furnace and its lower end supported on the fixed lower end wall of the furnace, the three described portions or the unitary liftable wall member substantially closing the end of the furnace and together forming a wall member that is generally U-shaped in horizontal section except at the upper end where it is adjacent the roof of the furnace, means forming an integral part of the liftable wall member for facilitating lifting of the wall member away from the lxed furnace structure, locking means fixed to the upper and lower ends of said wall member and adapted to interlock with complementary locking members provided on the xed furnace structure to hold the liftable wall member adjacent and in operative relation to the fixed furnace structure, said locking means being constructed and arranged to permit disengagement of the locking means from said locking member by mere vertical lifting of the unitary wall member.

3. An open hearth furnace comprising, in comhination, a fixed furnace structure including a back wall, a front wall, a roof supported by the back and front walls, and the lower portions of end walls at the opposite ends of the furnace structure; and a unitary liftable end wall inember at each end of the furnace structure, said unitary end wall member including a portion which is substantially vertical and is adapted to be aligned with and temporarily joined to the back wall of the furnace, another portion which is substantially vertical and is adapted to be aligned with and temporarily joined to the front wall of the furnace, a third portion which joins the other two portions and is inclined to the vertical and has its upper end adjacent the roof of the furnace and its lower end supported on said fixed lower portion of the end wail of the furnace, the unitary end wall member substantially closing the corresponding end of the furnace, means forming an integral part of the unitary wall member for facilitating lifting of the wall member away from the fixed furnace structure, locking .means fixed to the upper and lower ends of said wall member, locking members complementary to said locking means and being xedto the fixed furnace structure, the locking means and locking members when engaged holding the unitary Wall member adjacent and in operative relation to the fixed furnace structure, said locking means being constructed and arranged to permit disengagement of the locking means from said xed locking members by mere vertical lifting of the unitary wall member.

References Cited in the le 0f this patent UNITED STATES PATENTS Number Name Date 589,769 Wellman Sept. 7, 1897 1,376,617 Griggs May 3, 1921 15 Number Name Date 1,416,439 Barrows May 16, 1922 1,705,965 DeWolf Mar. 19, 1929 2,272,217 Longenecker Feb. 10, 1942 2,550,078 McDonald Apr. 24, 1951 2,593,481 Over Apr. 22, 1952 2,618,961 Williamson Nov. 25, 1952 FOREIGN PATENTS 10 Number Country Date 17,131 Great Britain 1912 OTHER REFERENCES Page 9 (Fig. 26) of Wall and Arch Construction, Bulletin No. 301 by Reintj es Co.