Web holdown and drive for corrugator double backer

Abstract

A double backer for curing the web bonding adhesive and drying the corrugated paperboard web utilizes a web holddown apparatus for maintaining the web in intimate drying contact with the lower heating units which does not require the use of a driven holddown belt. The holddown is provided instead by a series of parallel, flexible, closely spaced strips suspended above the web in the heating section and extending in the direction of web travel. By adjusting the supports to which the ends of the strips are attached, the portions of the lengths of the strips maintained in contact with the web may be varied. The holddown strips may be provided with strip supporting air bearings which also help dissipate moisture and heat. The web is pulled through the double backer by a downstream vacuum conveyor section comprising a series of transport belts to the upper surfaces of which a vacuum is applied and which may also be supported by air bearings to reduce friction and drive power requirements.

Dependencies are inferred from the claim text.