Abstract: An end closure system for selectively opening and closing at least one preselected guideway in a treatment chamber. The end closure system includes a plurality of vertically aligned panels, each having opposite ends slidably engaged in vertically disposed guide means. Connecting means are provided on each panel for raising or lowering a preselected panel and any panel above a preselected panel to provide access to the preselected guideway or guideways or to seal the guideway or guideways. In one embodiment of the invention lifting means are provided for engaging the connecting means on the preselected panel to raise and lower the preselected panel and any panels above the preselected panel.