초록 ▼

Flexible edge sealing membranes cooperate with the heating surface of a vacuum preheater and a web moving over the surface (1) to minimize air loss in the portions of the heating surface not covered by the web, (2) to prevent differential heating of the edges of the web induced by unrestricted air f

Flexible edge sealing membranes cooperate with the heating surface of a vacuum preheater and a web moving over the surface (1) to minimize air loss in the portions of the heating surface not covered by the web, (2) to prevent differential heating of the edges of the web induced by unrestricted air flow, and (3) to provide reduced friction contact with the edge portions of the web.

대표청구항 ▼

[ I claim:] [6.] A method for improving the heating efficiency of a vacuum hot plate of the type having a heating surface supporting a moving web, the surface having a width exceeding the width of the web and vacuum openings in the surface through which air is drawn by a vacuum applied to the unders

[ I claim:] [6.] A method for improving the heating efficiency of a vacuum hot plate of the type having a heating surface supporting a moving web, the surface having a width exceeding the width of the web and vacuum openings in the surface through which air is drawn by a vacuum applied to the underside of the surface, said method comprising the steps of:(1) positioning a pair of flexible edge sealing membranes on the lateral edges of the hot plate to extend along and to overlie a lateral edge of the web on the heating surface and to rest upon a portion of the upper face of the web and on the heating surface laterally adjacent to the web; and(2) providing the membranes with a pattern of through-holes positioned to preclude alignment of the holes in the portions of the membranes resting on the heating surface with the vacuum openings.