Suction transfer system for high speed paper dryer

Claim 2

In a dryer in which the web to be dried is disposed outside of and below a length of the dryer fabric extending between two rolls in a dryer section having a single continuous fabric, apparatus including in combination a suction transfer device, and means mounting said device above said fabric length with said device extending from edge to edge of said fabric, means dividing said suction transfer device into side sections associated with the fabric edges and a central section between said side sections, said side sections including bottom plates adjacent to said fabric, said bottom plates being formed with undulations, said bottom plates being perforated in the regions of the crests of said undulations and unperforated in the regions of the troughs of said undulations, means for producing negative pressure in said side sections above said bottom plates, said center section comprising a central plate spaced above said fabric, respective seals with said fabric around the peripheries of said side sections, and a seal between the central plate at the entry end thereof and said fabric, said central plate diverging from said fabric in the direction of movement thereof to produce a slight negative pressure above said fabric in the area between said side sections.

Claim 3

A suction transfer device for a web comprising a pair of side sections and a center section, each of said side sections having a bottom wall undulating in a direction from the web entrance to said device to the web exit therefrom, said bottom walls being perforated in the regions of the crests and unperforated in the regions of the troughs of said undulations, respective seals around each of said bottom walls, a central plate between the side sections, and a seal at the entry end of the central plate, said central plate diverging from the bottom of the device in a direction from the entry end to the exit end.

Claim 4

A suction transfer device for a web comprising a pair of side sections and a center section, each of said side sections having a bottom wall undulating in a direction from the web entrance to said device to the web exit therefrom, said bottom walls being perforated in the regions of the crests and unperforated in the regions of the troughs of said undulations, respective seals around each of said bottom walls, a central plate between the side sections, and a seal at the entry end of the central plate, said central plate diverging from the bottom of the device in a direction from the entry end to the exit end.

Claim 5

In a dryer section in which the web to be dried is disposed outside of and below a length of the dryer fabric extending over a generally horizontal run from a take-off roll associated with the last roll of the press section to the first dryer cylinder of a dryer section having a single continuous fabric, apparatus including in combination, a generally horizontally disposed suction transfer device having a width substantially equal to that of said fabric and a length equal to the distance between a location adjacent to said take-off roll and a location adjacent to said cylinder, means mounting said suction transfer device in cooperative relationship with said dryer fabric over said distance whereby said device has an upstream end at which said fabric enters said device and a downstream end at which the fabric emerges from said device, said device comprising respective first and second seals extending along the length of said device from said upstream end to said downstream end, said seals being spaced inwardly from the edges of said fabric and in spaced relationship to each other to divide the device into a central section and a pair of side sections running along the edges of said fabric from said upstream end to said downstream end thereof, means including said first and second seals for forming seals with said fabric extending around the entire peripheries of each of said side sections, a third seal with said fabric extending across the upstream end of said central section, the downstream end of said central section being open, means for generating a slight negative pressure above said fabric throughout said central section, and means for producing negative pressure of a magnitude greater than said slight negative pressure throughout each of said side sections, each of said side sections including a perforated wall spaced from said fabric, said negative pressure producing means comprising means for producing a negative pressure above said walls, each of said perforated walls undulating in the direction of movement of said fabric, said perforations being located in the crest regions of said undulations with the through regions being unperforated.

Claim 6

In a dryer section in which the web to be dried is disposed outside of and below a length of the dryer fabric extending over a generally horizontal run from a take-off roll associated with the last roll of the press section to the first dryer cylinder of a dryer section having a single continuous fabric, apparatus including in combination, a generally horizontally disposed suction transfer device having a width substantially equal to that of said fabric and a length equal to the distance between a location adjacent to said take-off roll and a location adjacent to said cylinder, means mounting said suction transfer device in cooperative relationship with said dryer fabric over said distance whereby said device has an upstream end at which said fabric enters said device and a downstream end at which the fabric emerges from said device, said device comprising respective first and second seals extending along the length of said device from said upstream end to said downstream end, said seals being spaced inwardly from the edges of said fabric and in spaced relationship to each other to divide the device into a central section and a pair of side sections running along the edges of said fabric from said upstream end to said downstream end thereof, means including said first and second seals for forming seals with said fabric extending around the entire peripheries of each of said side sections, a third seal with said fabric extending across the upstream end of said central section, the downstream end of said central section being open, means for generating a slight negative pressure above said fabric throughout said central section, and means for producing negative pressure of a magnitude greater than said slight negative pressure throughout each of said side sections, each of said side sections including a perforated wall spaced from said fabric, said negative pressure producing means comprising means for producing a negative pressure above said walls, each of said perforated walls undulating in the direction of movement of said fabric, said perforations being located in the crest regions of said undulations with the through regions being unperforated.