Leveler Door for Coke Ovens

My invention relates generally to coke oven doors and more particularly to leveler doors for sealing the leveler opening in coke oven doors.

A coke oven door on the pusher side of the oven is usually provided with an opening near the top to permit the insertion of a leveler bar therethrough. The leveler bar is pushed into the coke oven chamber and reciprocally moved several times until the surface of the coal charge in the oven is substantially leveled. When the leveler bar is withdrawn from the coke oven, the leveler opening is closed using a door or lid, and the coking process is begun. During the coking process, gaseous distillation products are formed which result in the condensation of tar and pitch-like deposits in the area of the coke oven door and particularly its leveler door. If sulfur bearing coal is coked, a corrosive gas is, likewise, evolved. Heretofore, the leveler doors most commonly used are of heavy cast iron and a metal to metal seal is effected around the leveler opening by machining the edge of the leveler door and its corresponding seating surface on the cast iron coke oven door. These cast iron leveler doors have proved to be expensive and unsatisfactory in that the sealing edge of the door and its corresponding seating surface must be repeatedly cleaned to remove the tarry deposits in order to maintain the required metal to metal seal. If the seal area is not cleaned, the seal between the leveler door and over door is not achieved and gases escape. The case iron leveler doors and seating surfaces, likewise, are attacked by the corrosive gases generated by the coking process. Periodically, the coke oven doors must be removed from the coke ovens and the sealing surfaces of the leveler doors and seating surfaces are rebuilt by deposition of weld metal and subsequent machining operation. If these expensive maintenance operations are not frequently done, the build-up of tarry deposits and the action of the corrosive gases cause gaps between the conventional leveler door and its seating surface which results in the harmful emission of gaseous distillation products into the atmosphere. Prior attempts have been made to solve the problems of sealing leveler doors, for example, U.S. Pat. Nos. 2,442,391 - Wilputte, and 2,820,002 - Wolff. These attempts have not been completely successful in that they require relatively complicated leveler door constructions which are expensive to manufacture and maintain.

My invention solves the problems heretofore encountered by providing a leveler door which effectively seals the leveler opening and greatly reduces the maintenance previously required by such doors.

My invention further provides a leveler door which slidably engages the seating surface adjacent the leveler opening during closing and tightly seals the leveler opening due to its flexible, concave shape.

My invention still further provides a leveler door and sealing seat which are capable of withstanding the corrosive effects of the coke oven gases.

My invention further provides a leveler door which is adapted for use on any of the various coke oven doors used in the industry.

Briefly, my invention provides a leveler door for sealing the leveler opening in a coke oven door; the oven door of the type having conventional leveler door mounting and latching apparatus associated therewith. The leveler door of my invention comprises a flexible closure member, preferably stainless steel, possessing spring-like properties at elevated temperatures. The closure member has a generally concave shape and terminates in a flexible sealing edge at its outer periphery. The sealing edge is formed at an angle of less than 90.degree. relative to the plane of the leveler opening. Means for securing the closure member to the mounting and latching apparatus of the oven door are provided whereby the compressive closing force supplied by the mounting and latching apparatus causes the rear of the concave closure member to move toward the leveler opening, causing the sealing edge to concurrently flex outwardly from the leveler opening while slidably engaging the coke oven door adjacent the leveler opening. In the closed position, the concave shape of the closure member springably maintains the flexible sealing edge in compressive and sealing engagement with the area adjacent the leveler opening. A corrosion resistant and heat resistant sealing seat may also be provided on the oven door surrounding the leveler opening. The corrosion resistant sealing seat further reduces the need for maintenance and insures a more uniform and longer life seal between the leveler door and the oven door.

In the accompanying drawings:

FIG. 1 is a sectional plan view of a conventional coke oven door with a presently preferred embodiment of the leveler door of my invention mounted thereon;

FIG. 2 is a front elevation of one presently preferred embodiment of the leveler door and sealing seat of my invention;

FIG. 3 is a sectional view taken along line III--III of FIG. 2;

FIG. 4 is a partial sectional view of the sealing edge of the leveler door of my invention;

FIG. 5 is a sectional view similar to FIG. 3;

FIG. 6 is a front elevation showing another presently preferred embodiment of the leveler door of my invention mounted on a coke oven door;

FIG. 7 is a partial sectional plan view taken along line VII--VII of FIG. 6;

FIG. 8 is a side sectional view of another presently preferred embodiment of the leveler door of my invention;

FIG. 9 is a side sectional view of another presently preferred embodiment of the leveler door of my invention; and

FIG. 10 is a partial sectional view of the sealing edge and sealing seat of my invention.

Referring now to the drawings, FIG. 1 shows the leveler door of my invention, generally designated 5, mounted to conventional coke oven door 2. Coke oven door 2 is one of several popular door designs presently used in the industry. Oven door 2 is detachably mounted to coke oven 1, on the pusher side of the oven and sealably egages oven door frame 15 with the knife edge of U-shaped sealing ring 13. Coke oven door 2 has a leveler opening 4 therein and conventional leveler door mounting and latching apparatus, generally designated 3, associated therewith. The conventional leveler door mounting and latching apparatus 3 includes mounting members or strong-back 6 which is pivotally connected by hinge 7 to oven door 2. Strong-back 6 is locked in place during the leveler door closing operation by conventional latching bar 8. A compressive closing force is applied to leveler door 5 by way of hand wheel 9 which turns a conventional threaded lock screw. The lock screw compressively engages the rear of leveler door 5 during the closing operation. The leveler door 5 of my invention is adapted to replace the existing leveler door of conventional coke oven 2 with no modification to the conventional mounting and latching apparatus 3.

A presently preferred embodiment of my leveler door 5 suitable for use with conventional coke oven door 2 is shown in greater detail in FIGS. 1-3. Leveler door 5 comprises a closure member 10 constructed of a material which possesses spring-like properties at elevated temperatures, preferably stainless steel. The temperature adjacent leveler opening 4 during coking is generally about 900.degree. F; therefore, the material selected for closure member 10 should be capable of retaining its spring-like properties at this temperature. A preferable material for closure member 10 is stainless steel. The particular material selected should, also, have the capability of resisting the corrosive effects of the sulfur bearing gaseous products which are generated during the coking operation. A suitable stainless steel alloy also performs this task well.

Closure member 10, is likewise, light gauge, preferably about 3/16 inch in thickness, so as to achieve the desired flexibility. Closure member 10 is generally concave or dish-like in shape having rear portion 28 and terminating in flexible, sealing edge 11 at its outer periphery. The longitudinal, planar axis of the flange or flexible sealing edge 11 is formed at an angle of less than 90.degree. relative to the plane of leveler opening 4. As seen in FIG. 4, the angular relationship between sealing edge 11 and the plane of leveler opening 4 is designated as angle A. Angle A is less than 90.degree. and preferably about 75.degree., which permits flexible sealing edge 11 to flex outwardly during closing while sealably engaging the sealing area adjacent leveler opening 4. I have found that flexible sealing edge 11 slidably engages the sealing area adjacent leveler opening 4, moving outwardly approximately 1/32 inch during closing. Such movement causes the removal of tarry deposits from the sealing area and thus yields a much improved seal.

Closure member 10 may be formed in one piece as by pressing the desired concave shape from a single sheet of material. Closure member 10 may also be fabricated from several pieces of stainless steel and joined by welding. I have found, however, that the pressed construction yields a more flexible closure, it being noted that the welded seams of the fabricated structure tend to increase the rigidity of the closure member 10 due to the increased thickness of the weld joints. The pressed construction is, likewise, more capable of distorting or flexing under compression closing forces on its common centerlines to assure a metal to metal contact around the seat periphery of the leveler opening.

Leveler door 5 of FIGS. 2-3 may be easily adapted to fit the conventional mounting and latching apparatus 3 of coke oven door 2 of FIG. 1 by the addition of mounting bracket 25 and leveling pads 24. Mounting bracket 25 may be constructed of ductile cast iron and is generally rectangular in shape having a U-shaped channel 26 formed therein. Channel 26 is adapted to be mounted on mounting member 12 of latching apparatus 3 in the same manner as the conventional leveler door is presently mounted on oven door 2. Mounting bracket 25 is secured to the rear portion 28 of closure member 10, preferably by welding. Mounting bracket 25 has a flat, bearing surface 27 on the floor of the U-shaped channel 26 which is adapted to engage the driving end of the conventional lock screw during the closing operation. Leveling pads 24 are positioned on opposite sides of bracket 25 and extend outwardly from rear portion 28 of closure member 10. Pads 24 are adapted to engage seating lugs 29 of strong-back 6 in order to prevent rotative movement of closure member 10 when the lock screw is rotated during closing.

Leveler door 5 is mounted to conventional mounting and latching apparatus 3 and is pivoted into closing position around leveler opening 4 as shown in FIG. 1. Rotative movement of the hand wheel 9 causes the driving end of the lock screw to compressively engage bearing surface 27 of mounting bracket 25. This compressive force is transmitted by bracket 25 to the rear portion 28 of closure member 10, whereby, rear portion 28 flexes toward the leveler opening 4 causing sealing edge 11 to concurrently flex outwardly from the leveler opening 4 while compressively maintaining the sealing edge in sealing engagement with coke oven door 2 in the area adjacent leveler opening 4.

Mounting bracket 25 may be attached to the surface of rear portion 28 by weld bead 46 as shown in FIG. 3. Bracket 25 may also be secured in the manner depicted in FIG. 5, wherein the rear portion 28 of closure member 10 has a rectangular cut-out 16 formed therethrough to receive the lower section of bracket 25. Bracket 25 is then welded in place by weld beads 46 on both sides of rear portion 28. The embodiment of FIG. 5 yields an improved construction since the weld beads 46 on both sides of rear portion 28 distribute the compressive closing forces more evenly to closure member 10.

Referring now to FIG. 3, sealing edge 11 may be modified slightly to yield increased flexibility. In most conventional coke oven doors, leveler opening 4 is rectangular in shape. Leveler door 5 would, likewise, be rectangular in shape for those applications. Portions of sealing edge 11' intermediate the corners 21 of said rectangular shape are formed to extend outwardly a greater distance than corner portions 21. In this manner, intermediate edge portions 11' contact the sealing area adjacent leveler opening 4 prior to the time that corner portions 21 strike the sealing area. Hence, during the closing operation, intermediate edge portions 11' flex outwardly a greater extent than would be the case if sealing edge 11 is formed in a flat plane. It can, therefore, be appreciated that the greater flexibility provided by intermediate sealing edge 11' yields an improved seal between leveler doors 5 and leveler opening 4.

I have also found it preferable to include a sealing seat 20 around the area adjacent leveler opening 4. Sealing seat 20 is, likewise, constructed of a heat resistant and corrosion resistant material such as stainless steel. Sealing seat 20 is provided with a plurality of bolt holes around its periphery and is adapted to be detachably mounted to seating surface 19 of coke oven door 2. Threaded bolt holes 23 are formed in sealing surface 19 of coke oven door 2 to receive bolts 22 therein. Sealing seat 20 thus provides a very low maintenance and long life seal since it is not affected by the corrosive gases generated during the coking operation and is, therefore, not susceptible to the pitting usually found in conventional cast iron sealing seat 19.

Not only does the thin wall construction of closure member 10 yield an improved seal around leveler opening 4, it also provides a cooler door during operation. The thin wall construction of closure member 10 conducts a heat more rapidly than the conventional heavy, cast iron leveler doors presently used. I have found that in normal operation the temperature is approximately 450.degree.-500.degree. F on the outer surface of my leveler door which necessarily eliminates the need for heat shields which sometimes are employed on the leveler doors of the prior art.

Various securement means may be employed to adapt my leveler door for use on coke oven doors of various constructions. Referring now to FIGS. 6 and 7, the leveler door 5' is shown as it would appear mounted on the mounting and latching apparatus 3' of another conventional coke oven door 2' presently used in the industry. Coke over door 2' is characterized by conventional leveler door frame 30, detachably mounted to coke oven door 2', surrounding the leveler opening 4'. A conventional mounting frame 43 is attached to coke oven door 2' and extends outwardly therefrom adjacent leveler opening 4'. Leveler door mounting and latching apparatus 3' is, likewise, provided comprising conventional lever arm 37 which is pivotally attached by pivot hinge 36 to mounting frame 43. In the embodiment of FIGS. 6 and 7, leveler doors 5' comprises a flexible, closure member 10 having terminal sealing edge 11 at its outer periphery. Leveler door 5' is constructed much in the same manner as the embodiments of FIGS. 1-5.

However, in this embodiment, mounting bracket 25 is not employed since the mounting and latching apparatus 3' of coke oven door 2' differs from that of previously described coke oven door 2. A pair of mounting hinges 35 are weldably secured to rear portion 28 of leveler door 5' on either side of conventional lever arm 37. Mounting hinges 35 are pivotally connected by pivot hinge 36 to mounting frame 43 of oven door 2'. A generally U-shaped member 42 is secured to rear portion 28 of closure member 10 and is adapted to act as a stop or retainer when leveler door 5' is to be opened. Lever arm 37 is pivoted at pivot pin 36 independently of mounting hinges 35. Therefore, during the opening operation, lever arm 37 engages U-shaped member 42 thus permitting a door to be pulled open by further movement of lever arm 37. Lever arm 37 also includes a threaded locking screw 38, which is conventional in oven doors of this type. Oven door 2' also includes conventional latching bar 41 which lockably secures lever arm 37 in place during the closing operation. In order to accommodate the mounting and latching apparatus 3' of oven door 2', closure member 10 preferably includes reinforcement means at its rear portion 28. This is preferred since the compressive closing force generated by the mounting and latching apparatus 3' acts directly on rear portion 28 of closure member 10.

Closure member 10' may be pressed from one piece of thin gauge metal and then a section of rear portion 28 is removed in a piercing operation. In place of the removed section, a heavier gauge plate 31 may be inserted therein and welded to rear portion 28, FIGS. 6 and 7. Reinforcement may also be accomplished by the embodiment of FIG. 8 wherein closure member 10' is pressed from one piece of thin gauge material and a heavier gauge reinforcement plate 45 is welded to rear portion 28. In this manner, the compressive force generated by closing screw 38 will bear upon reinforcement plate 45 or plate 31 and evenly spread the compressive force over rear portion 28 without causing buckling or denting of the rear portion 28.

A bearing plate 32 may also be secured to rear portion 28 of closure member 10', if desired. Bearing plate 32 has a flat surface 34 of a diameter suitable to accept driving end 40 of locking screw 38. Bearing plate 32 may be weldably secured to plate 31 as in FIG. 7, or to reinforcing plate 45 in the manner shown in FIG. 8. Bearing plate 32 may also be used as the sole means of reinforcing rear portion 28 as shown in FIG. 9. In this embodiment, a cut-out portion is formed through rear portion 28 of closure 10 to receive bearing plate 32 therein. Weld beads 46 are applied on both sides of rear portion 28 to secure bearing plate 32 in place.

Leveler door 5' is adapted to seal leveler opening 4' adjacent conventional leveler door frame 30 of oven door 2'. However, conventional leveler door frame 30, as shown in FIG. 7, may be modified to accept the removable sealing seat 20' shown in FIG. 10. Sealing seat 20' is also preferably constructed of a stainless steel alloy having heat and corrosion resistant properties and is preferably about 3/8 inch in thickness. If sealing seat 20' is to be installed on conventional leveler door frame 30, the outwardly extending sealing surface 44 of FIG. 7 is removed by machining. The removable sealing seat 20' is then attached to conventional leveler door frame 30 by way of bolts 22' which are threadably secured within threaded bolt holes 23' formed along the machined surface 19 of leveler door frame 30. Sealing seat 20' may also be attached by way of conventional studs and nuts (not shown). Due to the relatively thin wall construction of conventional door frame 30, the bolt holes 23 may extend completely through the side walls of frame 30 and, therefore, a high temperature sealant is preferably applied to bolts 22' in order to prevent leakage of gases from the oven through both holes 23'.

While leveler door 5 has been previously described as being generally rectangular in shape, it can be appreciated that it may be modified to fit leveler door openings of any shape. For example, closure member 10 may be formed to be circular or oval in order to sealably contact either circular or oval leveler door openings. In such modified structures, leveler door 5 would still be flexible and would retain its concave or dish-like shape with the same flexible sealing edge as previously described. Leveler door 5 could also be further modified within the spirit of my invention to include a closure member which has a relatively rigid rear portion terminating in a flexible sealing edge at its outer periphery. The sealing edge would be formed at an angle of less than 90.degree. relative to the plane of the leveler opening as previously described. In such a modified structure, the rear portion of the closure could be a heavier gauge plate with the thinner gauge sealing edge attached thereto by welding or by bolts or the like.

While several presently preferred embodiments of my invention have been described herein, it is understood that certain modifications can be made without departing from the scope of the appended claims.