Coating apparatus including liquid sealant between compartments

Claim 1

Apparatus for treating a continuous surface of a web with different fluids including reactants comprising: at least a pair of treating chambers having a common wall therebetween and an entry and an exit slot disposed in respective side walls lying in the same general plane; a sealing chamber defined in part by said side walls; at least a third treating chamber having in common with said sealing chamber a wall opposed to said side walls; a first pair of slots in said opposed wall, each of said last mentioned slots being alined with one of said entry or exit slots of a separate prior recited treating chamber; a second pair of slots in said opposed wall which are external to said third treating chamber and each of said last mentioned slots being alined with a separate one of the other of said entry or exit slots; a treating fluid in each of said treating chambers at a level above said slots associated therewith; a liquid sealant disposed in said sealing chamber to a level above each of said slots, having a high-surface-tension characteristic and being immersible and inert with respect to each of said treating fluids; each of said slots being of a dimension whereby to retain said sealant by surface tension; and roller guide means operatively associated with each of said chambers whereby said web may enter and exit from said apparatus through said sealing chamber and travel sequentially through each of the alined pairs of slots for treatment in each of the three recited treating fluids.