US3081751A - Reversible water-cooled open hearth furnace doors - Google Patents

Description

March 19, 1963 R. J. DEMAISON 3,081,751

REVERSIBLE WATER--COOLED OPEN HEARTH FURNACE DOORS Filed Aug. 11. 1959 s sheets-snei 1 INVENTOR E J flz-"mw/so/v BY m4. 2 6/ March 19, 1963' R. J. DEMAISON Y 3,081,751

REVERSIBLE WATER-COOLED OPEN HEARTH FURNACE DOORS Filed Aug. 11, 1959 3 She ets-Sheet 2 ATTO N March 19; 1963 R J DEMAISON REVERSIBLE WATER-COOLED OPEN HEARTH FURNACE DOORS Filed Aug. 11, 1959 3 Sheets-Sheet 3 THZ EI.

INVENTOR A. J DEMA/SO/v M M %ZI% 3,081,751 REVERSKBLE WATEit-(IOOLED OPEN HEARTH FURNAOE DOORS Raymond J. Dernaison, Bronx, N.Y., assignor to Quigiey Company, inc, a corporation of New York Filed Aug. 11, 1959, Ser. No. 832,954 3 Claims. (Cl. 122-498) This invention relates to furnace doors for use on open hearth furnaces and in particular relates to the type of door which is water cooled and contains a refractory material insert or lining.

The principal feature of this invention is to provide a water cooled reversible furnace door having suitable refractory inserts or linings on both faces and capable of being reversed as desired to allow one face or the other to be brought into service without removing the door from the furnace.

Other features of the invention are to provide a reversible Water-cooled furnace door that is economical to repair due to the novel method employed in placing the refractory material in the furnace door and which in addition is long lived due to the increased heat transfer effected by the reinforcing, attaching and supporting means employed in placing the refractory material in the faces of the door. The necessity of removing the door from the furnace for repairs is entirely eliminated.

The present invention therefore contemplates certain improvements in the construction of the furnace door which definitely overcome one of the greatest difliculties encountered in the operation of an open hearth furnace. The common method of removing the single refractory faced doors periodically for repair is one which is very costly and time consuming and in addition requires a very large space just to effect the repairs.

The present invention may be briefly described as directed to an open hearth furnace door comprising a watercooled supporting frame faced on both sides with refractory material and reversible to bring either refractory facing into service. On the faces of the water-cooled supporting frame are placed a plurality of anchoring and reinforcing means for the insertion of suitable refractory material and said anchoring means, in addition to holding the refractory material in place, assists and controls the transfer of heat from the refractory material inserts to the supporting frame. The normal water cooling inlet and outlet pipes are employed to supply water to the door for cooling and will be disconnected at the unions when the door is to be reversed.

The furnace door is provided with a tilting pad and trunnion in the center of its lower edge to which a crank hook may be attached and the door lifted to a horizontal position. At its top edge, the furnace door is pivoted to permit such upward tilting and moreover is provided with a trunnion in axial alignment with the lower trunnion. Hence, when the door is in its horizontal position, it may be reversed by rotating it through 180 about a centrally located axis and thereafter lowered back to its normal vertical operative position. In this way, a new refractory facing is located on the furnace engaging side of the door while the damaged facing is located on the outside and may be repaired in place without any trouble whatsoever with the furnace in operation. The water-cooled supporting frame keeps the damaged face cool.

In the normal operation of the furnace, the door may be raised or lowered (in its own plane) in the usual way by means of one or two lifting chains. Where one chain is employed, the top trunnion is built right into the lifting eye.

Referring to the drawings:

FIG. 1 is a front elevation of an open hearth furnace door constructed in accordance with the invention;

FIG. 2 is a vertical section taken along the lines 2-2 of FIG. 1;

FIG. 3 is a front elevation of a modified form of fur nace door also constructed in accordance with the invention;

FIG. 4 is a vertical section taken along the lines 4-4 of FIG. 3;

FIG. 5 is a front View of one of the refractory blocks shown in FIG. 3;

FIG. 6 is an edge view of the refractory block shown in FIG. 5;

FIG. 7 is an enlarged sectional view of the refractory block shown in FIGS. 5 and 6; and

FIG. 8 is a detailed perspective view of the reinforcing grid embedded in the individual refractory blocks.

The improved furnace door comprises a rectangular symmetrical metal supporting frame it presenting a wide hollow rim portion 1i and a relatively narrow centrally located hollow body portion 12, the frame thus having passages for the circulation of water or other cooling fluid therethrough and serving as a cooling jacket for the refractory material. Water pipes 13 and 14 are tapped into the top rim portion of the frame adjacent its opposite ends and are detachably connected by couplings 15 and to to flexible inlet and outlet tubes 17' and 18, respectively. In one position of the door, the pipe 13 will be connected to the inlet tube 17 and the pipe 14 to the outlet tube 18, while in the reversed position of the door, the pipe .14 will be connected to the inlet tube 17 and the pipe 13 to the outlet tube '18.

A cylindrical sleeve or thimble 19 passes through the body portion 12 from one side of the door to the other and forms the customary wicket opening or peep hole for furnace observation.

in FIGS. 1 and 2, the furnace door is faced on both sides of the body portion 12 with refractory material in the form of monolithic slabs Z0 and 21. To insure the retention in place of the slabs, the inner walls 22 of the rim portion 11 are inclined with reference to the central body portion 12 in order to overhang the slabs around their perimeters. On its opposite sides, the body portion 12 has welded thereto a multitude of metal pins 23 which not only serve to reinforce the monolithic slabs and anchor them in place but in addition to serve as heat exchange elements to conduct heat from the slabs to the water-cooled supporting frame.

The monolithic slabs may be built into the supporting frame by casting, trowelling, spraying or in any other desired manner. After a certain period of time, the slabs will of course deteriorate under the influence of the furnace heat and will need to be repaired or replaced. Complete replacement will seldom be necessary, since the slabs may be readily repaired by patching or spraying. As before stated, when the slab in service becomes damaged, the door is reversed to bring the other slab into service, and then the damaged slab may be repaired from the outside while the door is in place and the furnace in operation.

In FIG. 2, the door is shown in its normal vertical operative position, being located on the outside of the furnace wall A and closing the door opening B therein. In the normal operation of the furnace, the door will be raised and lowered in its own plane to open and closed positions, respectively. This is done by means of a pair of lifting chains 24 attached to the top of the supporting frame through the medium of a lifter bar 25. The bar 25 is provided on its opposite ends with bifurcated brackets 26 having cross pins 27 which pass through eyes 28 of the lifting chains. The pins 27 and eyes 28 thus form a pivot about which the door may be swung upwardly (away from the furnace wall A) to a horizontal position for reversal and thereafter swung downwardly for return to its door closing position.

Below the lifter bar 25 and extending parallel thereto is a hanger bar 29 which is swivelled thereto by means of a trunnion bearing bolt 3% passing through openings in the two bars and having suitable washers which permit the hanger bar to be rotated freely with respect to the lifter bar. The hanger bar 29 could be rigidly attached to the top of the supporting frame (as in the second embodiment later described) but it is preferred, in tihs instance, to provide for a limited rocking motion between the bar and the supporting frame in order to allow the latter some freedom of movement as it is raised and lowered by the lifting chains 24 and also during its upward and downward swinging movements. Accordingly, the hanger bar 29, near its opposite ends, is formed with depending rectangular plates 29a connected by hinge pins 31 to bifurcated brackets a welded to the top of the supporting frame 10. As indicated by the dotted lines in FIG. 2, the lower edges of the plates 29a extend parallel to and closely adjacent the flat bases of the brackets 16a, permitting the desired amount of relative movement between the supporting frame and the hanger bar 29.

' It will now be seen that, when the door is swung upwardly to a horizontal position, it is free to be rotated through 180 for reversal, the axis of rotation passing centrally through the door which thus occupies the same relation to the other parts when either refractory facing is in use.

As a convenient and practical way of effecting the pivotal or swinging movements of the door, the supporting frame 10 is provided at its lower edge with a tilting pad 32 which is swivelled thereto by means of a threaded trunnion bearing stud or pin 33 arranged in axial alignment with the top trunnion bearing bolt 30. The free end of the tilting pad is formed with an eye 34 to receive the hook 35 of a lifting crane. As will be evident, the pad will not only serve as a connection between the lifting crane and the door but will also act to support the door in its horizontal position, its swivel connection with the door permitting it to be rotated through 180 for reversal in the manner above described.

It may be noted that, in this particular embodiment, a recess (not shown) will be formed in the sill or platform of the furnace to accommodate the lifting pad 32 and trunnion stud 33. This is because the door normally rests at its lower edge upon the furnace hearth for support and proper location. The limited relative rocking movement provided between the door and the hanger bar 29 facilitates the attachment of the crane hook 35 to the tilting pad 32.

Referring now to the second embodiment shown in FIGS. 3 to 8:

In this embodiment, the water-cooled supporting frame lfia is substantially the same as the frame 10 in the first embodiment described, comprising a hollow rim portion 11a and a central hollow body portion 12a. In this econd embodiment, however, the inner walls 22a of the rim portion are not inclined with respect to the body portion 12a but extend at right angles thereto so as to present rectangular spaces at opposite sides of the frame for the refractory material. In this second embodiment, also, the supporting frame is formed with a recess 36 to accommodate the lifting pad 32 and trunnion stud 33, thus avoiding the necessity of cutting a recess in the furnace sill or platform. The same wicket opening thimble 19 passes through the supporting frame for observation urposes, but in this disclosure is kept short in order to prevent burnoff.

As a characteristic feature of the second embodiment under discussion, the refractory facings on opposite sides of the supporting frame are in the form of separate blocks of panels individually attached to and supported on the supporting frame. One of the blocks, designated 40, is

shown in FIGS. 5 and 6. It is rectangular in shape and has embedded therein a metal grid consisting of two metal strips 41 and 42 arranged at right angles to each other and welded together in the zone of intersection. The opposite ends of each strip are bent outwardly from the plane of intersection to provide offsets 43 which extend in the direction of thickness of the blocks. The offsets 43 are split centrally and then bent in reverse directions to provide tabs 44- which extend parallel to the face of the block. The metal grid therefore not only affords a good reinforcement for the refractory block but also acts as an effective heat exchange element therefor.

As will be observed in FIGS. 6 and 7, the metal strips 41 and 4.2 in their plane of intersection are located substantially flush with the inner or cool face of the block and are formed with a central opening 45 to permit the block to be attached to the supporting frame. Such attachment is effected by a threaded stud 46 welded to the face of the central body portion 12a of the supporting frame and passing through the opening 45. A nut 47 is screwed onto the threaded stud clamps the block in place. In this connection, it is pointed out that the block, during casting, is cored out to leave a hole 45 through the block to give access to the fastening means when the block is attached to the supporting frame. After attachment of the block, the hole 45 is filled with the same refractory material as the block is made of to protect the fastening means from the heat of the furnace.

FIGS. 3 and 4 show the furnace door as faced on both sides with the blocks 40, it again being noted that the blocks are individually attached to and supported by the metal supporting frame. While not necessary, it is desirable before mounting the blocks in place, to coat the faces of the supporting frame with high temperature cement in plastic condition in order to force the cement between the blocks and thus seal the joints between them, see in particular FIG. 7. To facilitate the flow of the cement into the joints, the blocks are bevelled or chambered at 48 on their inner or cool faces (see again FIG. 7 as well as FIG. 6). Nevertheless, after all the blocks have been anchored in place, the cement between the joints on the outer or heat exposed faces of the blocks is cut back a suitable distance in order to allow for expansion and contraction of the faces of the refractory blocks when the furnace is in operation.

The use of separate blocks or panels as refractory facings for the furnace door is particularly advantageous, because the blocks may be preformed and then readily mounted in place. Moreover, it ofen occurs that the refractory facings will become damaged in spots or limited areas and in such cases the damage can be repaired by merely removing the blocks in those areas and replacing them with new blocks of the same design. Of course, in removing any particular block, the refractory material which fills the cored out hole 45 must first be removed but that is a simple operation.

One further modification remains to be described. As shown in FIGS. 3 and 4, a single lifting chain 5% is employed for raising and lowering the furnace door during the operation of the furnace. Hence, a trunnion bearing bolt 51, which makes a swivel connection with the door through a hanger bar 52 fixed to the door, is provided at its upper end with an eye 53 to receive the looped end 54 of the lifting chain. In this instance, therefore, the eye 53 and chain loop 54 form a single pivotal connection which permits the door to be swung up to its horizontal position for reversal and then lowered back into place.

Any suitable high temperature refractory material may be used for forming the door facings. For example, the preformed blocks or panels 40 may be made of chromemagnesium, and the same material may be used for filling the cored out holes in the blocks. In the case of the monolithic slabs, shown in FIGS. 1 and 2, Roofchrome, which is essentially a chrome ore composition, may be employed and applied by casting, trowelling or spraying or otherwise. This Roofchrome material may also be used for making repairs, either to the monolithic slabs or to the preformed blocks, being applied readily by spraying in wet slurry form from a high pressure spray gun.

It will now be appreciated by those skilled in the art that the present invention represents a great advance in open hearth furnaces. The furnace doors have always presented a major repair problem since they can only be repaired by removing them from the furnace and replacing them by other doors. With the instant invention, the doors may be readily repaired without removing them from the furnace and while the furnace is in operation, thus saving much time and labor in the operation of the furnace.

The invention has been shown only in preferred form and by way of example, and it will be understood that many changes and modifications may be made without departing from its spirit. The invention therefore is not limited to any particular form or embodiment except insofar as such limitations are specified in the appended claims.

What is claimed is:

1. In combination,

(a) a reversible open hearth door, comprising (b) a metallic supporting frame faced on both sides with similar separate and distinct inserts of nonmetallic refractory material,

(c) means for supporting said door from the top of said frame and for raising and lowering said door substantially in a plane into open and closed position, comprising (d) lifting means above said frame,

(e) a pivotal connection at the top of said frame between said frame and said lifting means with a horizontal pivotal axis extending along the length of the door, and

(f) a swivel connection at the top of said frame between said frame and said lifting means and located intermediate of the sides of the door, said swivel connection having its axis extending crosswise of said door, substantially in the plane of said door,

(g) said pivotal connection and said swivel connection being connected in series between said lifting means and the top of said frame, and

(h) means for swinging said door forwardly and upwardly about said horizontal axis from said first mentioned plane to a raised substantially horizontal position and then back again and for supporting said door in said substantially horizontal position in conjunction with said door supporting means, and comprising (i) a lifting member, and

(j) means for forming a swivel connection between said lifting member and the bottom of said frame 7 intermediate the sides thereof coaxial with the top swivel connection (k) said swivel connections permitting rotation of said door '1 80 about said crosswise swivel axis, whereby 5 said door when in said raised substantially horizontal position can be rotated about said crosswise swivel axis through 1 80 While supported by said door supporting means (0) and said door swinging and supporting means (h) with said crosswise swivel swivel axis substantially horizontal.

2. The combination as described in claim 1, said means (c) for supporting said door from the top of the frame, comprising (1) a lifter bar located at the top of said frame and extending along said door,

(111) said pivotal connection (e) comprising means at the ends of the lifter bar for pivotally mounting said bar to said lifting means (d),

(It) said top swivel connection comprising a hanger bar underlying the lifter bar and extending therealong,

(o) said hanger bar having means at its ends pivotally mounting said hanger bar to the frame for limited movement about an axis parallel to said horizontal pivotal axis,

(p) said top swivel connection also comprising a trunnion interconnecting the intermediate section of said hanger bar and the intermediate section of said lifter bar.

3. The combination as described in claim 2, said supporting frame (b) being formed with passages for the circulation of a cooling medium therethrough, and being provided with inlet and outlet pipes leading to and from said passages, said pipes being interchangeably connected 35 to fixed water supply and water drain pipes to permit the door to be reversed.

- References Cited in the file of this patent UNITED STATES PATENTS Industrial Furnaces, vol. I (Trinks), published by John Wiley and Sons (New York), 1934 (page 308 relied on).

Claims (1)

1. IN COMBINATION, (A) A REVERSIBLE OPEN HEARTH DOOR, COMPRISING (B) A METALLIC SUPPORTING FRAME FACED ON BOTH SIDES WITH SIMILAR SEPARATE AND DISTINCT INSERTS OF NONMETALLIC REFRACTORY MATERIAL, (C) MEANS FOR SUPPORTING SAID DOOR FROM THE TOP OF SAID FRAME AND FOR RAISING AND LOWERING SAID DOOR SUBSTANTIALLY IN A PLANE INTO OPEN AND CLOSED POSITION, COMPRISING (D) LIFTING MEANS ABOVE SAID FRAME, (E) A PIVOTAL CONNECTION AT THE TOP OF SAID FRAME BETWEEN SAID FRAME AND SAID LIFTING MEANS WITH A HORIZONTAL PIVOTAL AXIS EXTENDING ALONG THE LENGTH OF THE DOOR, AND (F) A SWIVEL CONNECTION AT THE TOP OF SAID FRAME BETWEEN SAID FRAME AND SAID LIFTING MEANS AND LOCATED INTERMEDIATE OF THE SIDES OF THE DOOR, SAID SWIVEL CONNECTION HAVING ITS AXIS EXTENDING CROSSWISE OF SAID DOOR, SUBSTANTIALLY IN THE PLANE OF SAID DOOR, (G) SAID PIVOTAL CONNECTION AND SAID SWIVEL CONNECTION BEING CONNECTED IN SERIES BETWEEN SAID LIFTING MEANS AND THE TOP OF SAID FRAME, AND (H) MEANS FOR SWINGING SAID DOOR FORWARDLY AND UPWARDLY ABOUT SAID HORIZONTAL AXIS FROM SAID FIRST MENTIONED PLANE TO A RAISED SUBSTANTIALLY HORIZONTAL POSITION AND THEN BACK AGAIN AND FOR SUPPORTING SAID DOOR IN SAID SUBSTANTIALLY HORIZONTAL POSITION IN CONJUNCTION WITH SAID DOOR SUPPORTING MEANS, AND COMPRISING (I) A LIFTING MEMBER, AND (J) MEANS FOR FORMING A SWIVEL CONNECTION BETWEEN SAID LIFTING MEMBER AND THE BOTTOM OF SAID FRAME INTERMEDIATE THE SIDES THEREOF COAXIAL WITH THE TOP SWIVEL CONNECTION (K) SAID SWIVEL CONNECTIONS PERMITTING ROTATION OF SAID DOOR 180* ABOUT SAID CROSSWISE SWIVEL AXIS, WHEREBY SAID DOOR WHEN IN SAID RAISED SUBSTANTIALLY HORIZONTAL POSITION CAN BE ROTATED ABOUT SAID CROSSWISE SWIVEL AXIS THROUGH 180* WHILE SUPPORTED BY SAID DOOR SUPPORTING MEANS (C) AND SAID DOOR SWINGING AND SUPPORTING MEANS (H) WITH SAID CROSSWISE SWIVEL SWIVEL AXIS SUBSTANTIALLY HORIZONTAL.

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