US 5,507,104 A · Web drying apparatus

Abstract

A paper machine comprising a single tier drying section including at least two dryer groups is disclosed. In one group, the axes of rotation of at least two consecutive drying cylinders lie substantially in a plane, and the axes of rotation of the vacuum rolls are disposed below the plane of dryer cylinders. In the next group, the axes of rotation of at least two consecutive drying cylinders lie substantially in a further plane which is non-coplanar with the plane defined by the dryers of the first dryer group. The vacuum rolls of the second dryer group have their axes of rotation disposed above the further plane. The dryer transfer which transfers the web from one dryer group to the next one includes a joint run of the felts of the respective dryer sections and a vacuum roll at the downstream end of the joint run. The joint run receives the web between the felts when the web passes through the joint run. The vacuum roll is disposed at the downstream end of the joint run for positively maintaining the web in close conformity with the receiving felt when the felts diverge downstream from the joint run. The felts are free from restraining devices as they pass through the joint run. A method for drying a web employing the disclosed apparatus is also disclosed.

Claims16

Dependent claims

A paper machine comprising a drying section including at least two dryer groups:

A. one said dryer group including:
i. a plurality of drying cylinders having roll surfaces for contacting one major surface of a web and axes of rotation, the axes of rotation of at least two consecutive drying cylinders of said plurality of drying cylinders lying substantially in a first plane, and
ii. a vacuum roll having an axis of rotation disposed below said first plane and a roll surface disposed in close proximity to the respective roll surfaces of said two consecutive drying cylinders of said one dryer group;
and
B. another said dryer group including:
i. another plurality of drying cylinders having roll surfaces for contacting the other major surface of a web and axes of rotation, the axes of rotation of at least two consecutive drying cylinders of said another plurality of drying cylinders lying substantially in a further plane which is non-coplanar with said first plane, and
ii. a vacuum roll having an axis of rotation disposed above said further plane and a roll surface disposed in close proximity to the respective roll surfaces of said two consecutive members of said another dryer group.

4 more elements

A dryer section comprising:

A. adjacent first and third rolls, each of which is a steam-heated dryer cylinder, having axes of rotation disposed substantially in a first plane;
B. adjacent second and fourth rolls, each of which is a non-steam-heated vacuum roll, respectively for transferring a web from said first roll to said third roll and from said third roll to further apparatus, said second and fourth rolls having axes of rotation disposed substantially in a second plane which is substantially parallel to but non-coplanar with said first plane;
C. a first felt successively wrapping about said first, second, third, and fourth rolls for conveying a web to and from each of said rolls wrapped by said first felt, the portions of said first felt running from said first roll to said second roll and from said third roll to said fourth roll defining leading runs of said felts, and the portion of said first felt running from said second roll to said third roll defining a following run of said felt, wherein the consecutive rolls at the respective ends of at least one said leading run are in close proximity;
D. adjacent fifth and seventh rolls, each of which is a steam-heated dryer cylinder, having axes of rotation disposed substantially in a third plane;
E. adjacent sixth and eighth rolls, each of which is a non-steam-heated vacuum roll, respectively for transferring a web from said fifth roll to said seventh roll and from said seventh roll to further apparatus, said sixth and eighth rolls having axes of rotation disposed substantially in a fourth plane which is substantially parallel to but non-coplanar with said third plane;
F. a second felt successively wrapping about said fifth, sixth, seventh, and eighth rolls for conveying a web to and from each of said rolls wrapped by said second felt, the portions of said second felt running from said fifth roll to said sixth roll and from said seventh roll to said eighth roll defining a leading run of said felt, and the portion of said second felt running from said sixth roll to said seventh roll defining a following run of said felt, wherein the consecutive rolls at the respective ends of at least one said leading run are in close proximity;
wherein at least one of said third and fourth planes is non-coplanar with at least one of said first and second planes.

4 more elements

Dependencies are inferred from the claim text.

Web drying apparatus

Life of this patent

Web drying apparatus

Life of this patent

Abstract

Claims16