Apparatus for supporting articles during exposure to a gaseous or vaporous medium

Conveying apparatus for supporting sheets during exposure to a gaseous medium, said apparatus comprising a first endless conveyor having an upstanding run, a second endless conveyor having an upstanding run substantially parallel to said first endless conveyor upstanding run, each of said endless conveyors including a pair of endless drive members carrying brackets with the brackets of each pair of drive members being aligned, the aligned brackets of said first endless conveyor being joined by fixed support bars extending therebetween and connected thereto, movable support bars, each of said brackets of said first endless conveyor further having carrier means for said movable support bars disposed between said fixed support bars, said brackets of said second endless conveyor having carrier means for said movable support bars, an endless supporting web associated with said first endless conveyor and generally disposed between paths of movement of said fixed support bars and said movable support bars, drive means for driving said endless conveyors in unison, feed means extending between upper portions of said runs for sequential engagement with said movable support bars carried by said first endless conveyor brackets and moving each movable support bar between adjacent ones of said fixed supports across the space between said runs and depositing each movable support in one of second endless conveyor brackets while pulling a generally horizontal loop of said endless supporting web, retaining means for retaining said movable support bars in said second endless conveyor brackets, and return means extending between lower portions of said runs for returning said movable supports to said first endless conveyor and retraction of said loops.