Method and apparatus for coating a porous substratum
AssigneeStork Brabant B.V.
InventorCornelis Blaak
Life of this patent
Estimating the term…
Abstract
Coating a porous substratum with a viscous substance is performed by means of a rotatable cylindrical sieve (plain-mesh screen), comprising an internal squeegee for pressing said substance through the perforations of the screen. The substratum are passed in contact with the screen and is supported at the contact zone by a roller. Although the peripheral speeds of the screen and the substratum is substantially equal, the rotational speed of the support roller is such, that its peripheral speed is either smaller or greater than that of the substratum to an extent of at least 5%. This avoids the occurrence of the phenomenon of pinhole formation in the coated substratum.
Claims29
A method of coating a permeable substratum with a viscous substance comprising:
- moving the substratum at a given speed;
- applying the substance to the moving substrate at an application location;
- supporting the substrate against the means applying the substance with support means having a surface which contacts the substratum;
- moving the support means so that the surface thereof which contacts the substratum moves at a speed which differs from the given speed of the substratum.
A method of coating a permeable substratum with a viscous substance comprising:
- moving the substratum at a given speed and in a given direction between the periphery of a rotatable cylindrical screen having perforations in its periphery and the periphery of a support roller, while holding the portion of the periphery of the screen and the support roller in contact with the substratum;
- supplying the substance internally of the cylindrical screen and pressing the substance through the perforations of the screen;
- rotating the cylindrical screen so that its periphery has a speed substantially equal to the given speed of the substratum in the direction of the substratum where the screen and substratum are held in contact;
- and
- rotating the support roller so that its periphery has a speed differing from the given speed of the substratum by at least substantially five percent, and rotates in the direction of the substratum where the substratum and the support roller are in contact.
An apparatus for coating a permeable substratum with a viscous substance, comprising:
- means for moving the substratum at a given speed;
- application means for applying the substance to the substratum;
- support means having a surface in contact with the substratum, for urging the substratum to contact the application means;
- means for moving the surface of the support means so that the surface has a speed which differs from the speed of the substratum.
An apparatus for coating a permeable substratum, with a viscous substance, comprising:
- means for moving the substratum at a given speed and in a given direction,
- a cylindrical screen having a periphery with perforations therein, the substratum moving means moving the substratum in contact with the screen;
- the screen containing the substance therein;
- means for pressing the substance through the perforations of the periphery of the screen;
- means for rotating the screen so that the periphery of the screen travels at the given speed of the substratum and in the given direction of the substratum where the substratum contacts the screen;
- a support roller having a periphery in contact with the substratum, the support roller urging the substratum to contact the screen;
- means for rotating the support roller so that the periphery of the support roller has a speed which differs from the speed of the substratum by at least five percent.
Dependencies are inferred from the claim text.