Apparatus for coating traveling webs of paper or cardboard

An applicator for coating a web of paper or cardboard, comprising:

• a belt having an outer surface for carrying coating material from a supply of coating material to a web to be coated, and the belt outer surface cooperating with a web on a backing roll for applying the coating material to the web;
• the belt having an inner surface;
• two guide rolls for the inner surface of the belt and arranged symmetrically to the backing roll, to the support roll and to the supplemental support roll supporting the support roll;
• and at least one of the two guide rolls being a drive roll engaging the inner surface of the belt for driving the belt to move past the web for delivering coating material to the web, the drive roll having a first diameter;
• a support roll also engaging the inner surface of the belt and located at the web and opposed to the backing roll for supporting the belt to define a coating nip between the belt and the web at the backing roll;
• the support roll having a second diameter which is relatively smaller than the first diameter of the drive roll;
• and
• at least one supplemental support roll in contact with the support roll for supporting the support roll against the belt, the belt being thereby pressed against the web and the backing roll at the nip;
• wherein the supplemental support roll for supporting the support roll is a single roll having a third diameter which is relatively larger than the second diameter of the support roll;
• the guide rolls having opposite ends and the belt having opposite edges;
• and
• sealing devices located at the opposite ends of the guide rolls and in the regions of the opposite edges of the belt, the sealing devices having upper edges located above the level of the supply of coating material being supplied to the belt.

An applicator for coating a web of paper or cardboard, comprising:

• a belt having an outer surface for carrying coating material from a supply of coating material to a web to be coated, and the belt outer surface cooperating with a web on a backing roll for applying the coating material to the web;
• the belt having an inner surface;
• a drive roll engaging the inner surface of the belt for driving the belt to move past the web for delivering coating material to the web, the drive roll having a first diameter;
• a support roll also engaging the inner surface of the belt and located at the web and opposed to the backing roll for supporting the belt to define a coating nip between the belt and the web at the backing roll;
• the support roll having a second diameter which is relatively smaller than the first diameter of the drive roll;
• and
• two supplemental support rolls in contact with the support roll for supporting the support roll against the belt, the belt being thereby pressed against the web and the backing roll at the nip;
• each of the supplemental support rolls being of a smaller diameter than the second diameter of the support roll;
• the supplemental support rolls being arranged symmetrically to a plane passing through axes of rotation of the backing roll and the support roll.

An applicator for coating a web of paper or cardboard, comprising:

• a belt having an outer surface for carrying coating material from a supply of coating material to a web to be coated, and the belt outer surface cooperating with a web on a backing roll for applying the coating material to the web;
• the belt having an inner surface;
• a drive roll engaging the inner surface of the belt for driving the belt to move past the web for delivering coating material to the web, the drive roll having a first diameter;
• a support roll also engaging the inner surface of the belt and located at the web and opposed to the backing roll for supporting the belt to define a coating nip between the belt and the web at the backing roll;
• the support roll having a second diameter which is relatively smaller than the first diameter of the drive roll;
• and
• at least one supplemental support roll in contact with the support roll for supporting the support roll against the belt, the belt being thereby pressed against the web and the backing roll at the nip;
• wherein there is a plane of symmetry through axes of the support roll and the drive roll and extending between a pair of supplemental support rolls which includes said at least one supplemental support roll, said plane of symmetry being inclined with respect to a vertical axis.

An applicator for coating a web of paper or cardboard, comprising:

• a belt having an outer surface for carrying coating material from a supply of coating material to a web to be coated, and the belt outer surface cooperating with a web on a backing roll for applying the coating material to the web;
• the belt having an inner surface;
• a drive roll engaging the inner surface of the belt for driving the belt to move past the web for delivering coating material to the web, the drive roll having a first diameter;
• a support roll also engaging the inner surface of the belt and located at the web and opposed to the backing roll for supporting the belt to define a coating nip between the belt and the web at the backing roll;
• the support roll having a second diameter which is relatively smaller than the first diameter of the drive roll;
• and
• at least one supplemental support roll in contact with the support roll for supporting the support roll against the belt, the belt being thereby pressed against the web and the backing roll at the nip;
• wherein there is a plane of symmetry through axes of the backing roll, the support roll and the drive roll which is inclined with respect to a vertical axis.