Apparatus for coating a web

Claim 2

In a web coating apparatus employing a coating roll and means for feeding the web into contact with the coating roll periphery which carries a coating material thereon, the improvement comprising: means defining an air chamber overlying the back of the web at the position where the web is in contact with the coating roll, air blowing means for pressurizing said air chamber, said air chamber being provided with a flexible membrane which directly overlies the back of the web, said flexible membrane being provided with at least one lateral opening parallel to the axis of the coating roll such that said flexible membrane flexes under static air pressure within said air chamber towards the back of said web but does not contact the back of said web, and wherein, air escaping from said chamber between said flexible membrane and said web acts to form dyanmic air pressure means therebetween and wherein said opening within said flexible membrane directly applies static air pressure against said web.

Claim 3

The web coating apparatus as claimed in claim 1, wherein said air cHamber further comprises a plate facing said web and having at least one opening therein parallel to and in alignment with the opening within said flexible membrane, said plate being positioned to the side of said flexible membrane opposite that of said web.

Claim 4

The web coating apparatus as claimed in claim 1, wherein said opening within said flexible membrane comprises a slit extending at least the width of said web.

Claim 5

The web coating apparatus as claimed in claim 1, wherein said membrane comprises a flexible film.

Claim 6

In a web coating apparatus employing a coating roll and means for feeding the web into contact with the coating roll periphery which carries a coating material thereon, the improvement comprising: a backing roll and a lap roll positioned on opposite sides of said coating roll with said web in running contact therewith and under tension, said lap roll and said backing roll being positioned such that said tension web is normally spaced from the periphery of said coating roll, an air chamber overlying the back of said web and being movable towards said web to press said web against the periphery of said coating roll, said air chamber including a bottom plate and having a plurality of spaced, laterally extending openings parallel to the axis of rotation of said coating roll, pressurized air generating means coupled to said air chamber for pressurizing said chamber such that said pressurized air passing through said openings of said bottom plate presses the back of said web against said coating roll periphery, and wherein the openings within the bottom plate of said air chamber are three in number and comprise parallel, lateral slits with the central slit being upstream of the axis of rotation of the coating roll.

Claim 7

In a web coating apparatus employing a coating roll and means for feeding the web into contact with the coating roll periphery which carries a coating material thereon, the improvement comprising: a backing roll and a lap roll positioned on opposite sides of said coating roll with said web in running contact therewith and under tension, said lap roll and said backing roll being positioned such that said tension web is normally spaced from the periphery of said coating roll, an air chamber overlying the back of said web and being movable towards said web to press said web against the periphery of said coating roll, said air chamber including a bottom plate and having a plurality of spaced, laterally extending openings parallel to the axis of rotation of said coating roll, pressurized air generating means coupled to said air chamber for pressurizing said chamber such that said pressurized air passing through said openings of said bottom plate presses the back of said web against said coating roll periphery, and wherein the openings within the bottom plate of said air chamber are three in number and comprise parallel, lateral slits with the central slit being upstream of the axis of rotation of the coating roll.