Charging hole cover seal

Claim 1

A structure for sealing a charging hole on a coke oven battery top comprising: (a) an annulus-shaped frame section projecting upwardly from the battery top and peripherally surrounding the charging hole and having a generally vertical inner side adjacent the charging hole, and a generally vertical outer side remote from the charging hole and a generally horizontal top end, said top end being positioned between said inner and outer sides and, itself, having integral, concentric inner and outer planar surfaces between which there is interposed a concentric circular groove containing a particulate material; (b) a disc-shaped cover section superimposed over said charging hole and having a lower end surface disposed toward the charging hole, a peripheral lateral surface inwardly spaced from and concentrically arranged with respect to the inner side of the frame section, and an upper end surface having a lateral lip extension vertically abutting the inner planar surface of the frame section top end, said lip extension having a terminal, peripheral and downwardly projecting tongue engaging said groove of the frame section top end, such that a primary, inward continuous gas seal is formed between said lip extension and said inner planar surface of the frame section top end, and a secondary, outward continuous gas seal is formed between said tongue and said groove; (c) at least two lugs projecting radially outwardly from the lateral surface of the cover section; and (d) at least two ledges projecting radially inwardly from the inner side of the frame section such that the cover section may be elevated so as to allow fluid communication between the charging hole and ambient air by superimposing each of said lugs on one of said ledges.