Method for floating and drying a web

Claim 1

A method of supporting and drying a coated web comprising the steps of: maintaining a static air pressure of not less than 5mm H20 between the web and an air impinging plate having a number of holes therein, the dimensions and positions of the holes being defined by the following conditions: i. Alpha selected between 70* and 110*, inclusive ii. Beta selected between -20* and +20*, inclusive iii. s selected between 3mm and 7mm, inclusive iv. the ratio d/s selected between 3 and 15, inclusive v. the ratio p/d selected between 1.5 and 2.5, inclusive vi. i selected between 0.7p and 200mm, inclusive vii. e is determined such that the air impinging holes are uniformly distributed over the area of the plate according to said conditions, where Alpha is the angle between the direction of feed of the web and the direction of the lines connecting the centers of columns of holes in the direction generally transverse to the direction of web feed, Beta is the angle at which the lengthwise direction of the holes is inclined to the lines connecting the centers of columns of holes in the direction generally transverse to the direction of the web feed, d is the length of the holes, s is the width of the holes, l is the distance between the adjacent holes, p is the distance between the adjacent lines of the holes, and e is the length of the lateral discrepancy of the holes in adjacent lines of holes, and the ratio of the area of the holes to the entire area of the plate is not more than 5 percent; feeding the web across the air impinging plate without contacting the surface of the plate by the static air pressure maintained beneath the plate; and drying the coated surface of the web by use of the air impinging on the film from the holes in the plate.

Claim 2

A method of supporting and drying a coated web comprising the steps of: maintaining a static air pressure of not less than 5mm H20 between the web and an air impinging plate having a number of holes therein, the dimensions and positions of the holes being defined by the following conditions: i. Alpha selected between 70* and 110*, inclusive ii. Beta selected between -20* and +20*, inclusive iii. s selected between 3mm and 7mm, inclusive iv. the ratio d/s selected between 3 and 15, inclusive v. the ratio p/d selected between 1.5 and 2.5, inclusive vi. i selected between 0.7p and 200mm, inclusive vii. e is determined such that the air impinging holes are uniformly distributed over the area of the plate according to said conditions, where Alpha is the angle between the direction of feed of the web and the direction of the lines connecting the centers of columns of holes in the direction generally transverse to the direction of web feed, Beta is the angle at which the lengthwise direction of the holes is inclined to the lines connecting the centers of columns of holes in the direction generally transverse to the direction of the web feed, d is the length of the holes, s is the width of the holes, l is the distance between the adjacent holes, p is the distance between the adjacent lines of the holes, and e is the length of the lateral discrepancy of the holes in adjacent lines of holes, and the ratio of the area of the holes to the entire area of the plate is not more than 5 percent; feeding the web across the air impinging plate without contacting the surface of the plate by the static air pressure maintained beneath the plate; and drying the coated surface of the web by use of the air impinging on the film from the holes in the plate.

Claim 3

An apparatus for floating and drying a flexible web having a coated layer thereon on a film of air comprising in combination: a plate having a plurality of openings therethrough, said openings being arranged in a predetermined pattern in accordance with the following conditions: i. Alpha selected between 70* and 110*, inclusive ii. Beta selected between -20* and +20*, inclusive iii. s selected between 3mm and 7mm, inclusive iv. the ratio d/s selected between 3 and 15, inclusive v. the ratio p/d selected between 1.5 and 2.5, inclusive vi. l selected between 0.7p and 200 mm, inclusive vii. e is determined such that the openings in said plate are uniformly distributed on the plate in accordance with said conditions, where Alpha is the angle between the direction of the feed of the web and the direction of the lines connecting the centers of columns of holes in the direction generally transverse to the direction of web feed, Beta is the angle at which the lengthwise direction of the holes is inclined to the lines connecting the centers of columns of holes in the direction generally transverse to the direction of web feed, d is the length of the holes, S is the width of the holes, l is the distance between the adjacent holes, p is the distance between the adjacent lines of holes, and e is the length of lateral discrepancy of the holes in the adjacent lines of holes, and the ratio of the area of the holes to the entire area of the plate is not more than 5 percent, a plenum chamber communicating with a pneumatic pressure source, said plate forming one surface of said plenum chamber, and means for moving said flexible web across said plate, whereby the web is supported by air impinging from said openings in said plate and simultaneously dries the coated layer thereon without allowing the film strip to contact the surface of the plate.

Claim 4

An apparatus for floating and drying a flexible web having a coated layer thereon on a film of air comprising in combination: a plate having a plurality of openings therethrough, said openings being arranged in a predetermined pattern in accordance with the following conditions: i. Alpha selected between 70* and 110*, inclusive ii. Beta selected between -20* and +20*, inclusive iii. s selected between 3mm and 7mm, inclusive iv. the ratio d/s selected between 3 and 15, inclusive v. the ratio p/d selected between 1.5 and 2.5, inclusive vi. l selected between 0.7p and 200 mm, inclusive vii. e is determined such that the openings in said plate are uniformly distributed on the plate in accordance with said conditions, where Alpha is the angle between the direction of the feed of the web and the direction of the lines connecting the centers of columns of holes in the direction generally transverse to the direction of web feed, Beta is the angle at which the lengthwise direction of the holes is inclined to the lines connecting the centers of columns of holes in the direction generally transverse to the direction of web feed, d is the length of the holes, S is the width of the holes, l is the distance between the adjacent holes, p is the distance between the adjacent lines of holes, and e is the length of lateral discrepancy of the holes in the adjacent lines of holes, and the ratio of the area of the holes to the entire area of the plate is not more than 5 percent, a plenum chamber communicating with a pneumatic pressure source, said plate forming one surface of said plenum chamber, and means for moving said flexible web across said plate, whereby the web is supported by air impinging from said openings in said plate and simultaneously dries the coated layer thereon without allowing the film strip to contact the surface of the plate.