US 5,495,678 AGranted

Drying module and dryer sections that make use of same, in particular for a high-speed paper machine

AssigneeValmet Paper Machinery Inc.

InventorsAntti Ilmarinen, Heikki Ilvespaa/, Antti Kuhasalo, Jouko Yli-Kauppila, Pertti Heikkila/, Iikka Jokioinen, Matti Korpela, Henrik Petterson, Mikko Karvinen, Va/ ino/ Sailas, Pekka Taskinen, Dick Parker

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Abstract

A method and device for drying a paper web wherein the paper web is supported on a drying wire without long open draws of the web. The paper web is contact-dried by pressing it with the drying wire onto a face of a contact-drying cylinder whose diameter is greater than about 1.5 m on a sector b whose magnitude is greater than about 180.degree.. The web is evaporation-dried as blowing-on drying and/or as through-drying by means of high-velocity drying-gas jets applied to the web on the drying wire on the face of the following large-diameter cylinder whose diameter is greater than about 2 m on a sector a having a magnitude greater than about 180.degree. while the web is on the side of the outside curve. The web to be dried is passed over a sector c of the suction roll which is subjected to negative pressure while the web is supported on the drying wire at the side of the outside curve. The magnitude of the sector of the suction roll has a magnitude greater than about 160.degree. and the diameter of the suction roll is less than the diameter of the contact-drying cylinder.

Claims30

Dependent claims

Drying module for a dryer section of a paper machine, comprising

a drying wire guided in a loop by guide rolls,
a large-diameter cylinder having a diameter greater than about 2 m and arranged inside the loop of the drying wire, a web being carried on said drying wire over a contact sector a of said large-diameter cylinder, said sector a having a magnitude greater than about 180.degree.,
said large-diameter cylinder having an outer mantle provided with grooves and/or being penetrable by drying gas,
a drying hood arranged over the contact sector a of said large-diameter cylinder, said drying hood having an interior and a nozzle field arranged in said interior in proximity to an outer face of the web, said nozzle field applying drying-gas jets at a high velocity against the web over a substantial area of the contact sector a,
smooth-faced heated contact-drying cylinders arranged in proximity to, and at both sides of, said large-diameter cylinder, said contact-drying cylinders having diameters less than the diameter of said large-diameter cylinder and being arranged outside the drying-wire loop, the web being carried on said drying wire over contact sectors b of each of said contact-drying cylinders, said sectors b having a magnitude greater than about 180.degree., and
at least one reversing suction roll arranged adjacent to a respective one of said contact-drying cylinders, said suction roll being arranged inside the drying-wire loop and having a diameter less than the diameter of said contact-drying cylinders, the web being carried on said drying wire over a contact sector c of said suction roll, said sector c having a magnitude greater than about 180.degree..

3 more elements

A dryer section for drying a web, comprising

at least one drying module, said at least one drying module comprising
a drying wire guided in a loop by guide rolls,
a large-diameter cylinder having a diameter greater than about 2 m and arranged inside the loop of the drying wire, a web being carried on said drying wire over a contact sector a of said large-diameter cylinder, said sector a having a magnitude greater than about 180.degree.,
said large-diameter cylinder having an outer mantle provided with grooves and/or being penetrable by drying gas,
a drying hood arranged over the contact sector a of said large-diameter cylinder, said drying hood having an interior and a nozzle field arranged in said interior in proximity to an outer face of the web, said nozzle field applying drying-gas jets at a high velocity against the web over a substantial area of the contact sector a,
smooth-faced heated contact-drying cylinders arranged in proximity to, and at both sides of, said large-diameter cylinder, said contact-drying cylinders having diameters less than the diameter of said large-diameter cylinder and being arranged outside the drying-wire loop, the web being carried on said drying wire over contact sectors b of each of said contact-drying cylinders, said sectors b having a magnitude greater than about 180.degree., and
at least one reversing suction roll arranged adjacent to a respective one of said contact-drying cylinders, said suction roll being arranged inside the drying-wire loop and having a diameter less than the diameter of said contact-drying cylinders, the web being carried on said drying wire over a contact sector c of said suction roll, said sector c having a magnitude greater than about 180.degree., and
at least one group of drying cylinders having a single-wire draw, said single-wire draw group comprising contact-drying cylinders in a first row, reversing cylinders in a second row spaced from said first row, and a drying wire for pressing the web against said contact-drying cylinders.

5 more elements

A dryer section for drying a web, comprising

at least one drying module, said at least one drying module comprising
a drying wire guided in a loop by guide rolls,
a large-diameter cylinder having a diameter greater than about 2 m and arranged inside the loop of the drying wire, a web being carried on said drying wire over a contact sector a of said large-diameter cylinder, said sector a having a magnitude greater than about 180.degree.,
said large-diameter cylinder having an outer mantle provided with grooves and/or being penetrable by drying gas,
a drying hood arranged over the contact sector a of said large-diameter cylinder, said drying hood having an interior and a nozzle field arranged in said interior in proximity to an outer face of the web, said nozzle field applying drying-gas jets at a high velocity against the web over a substantial area of the contact sector a,
smooth-faced heated contact-drying cylinders arranged in proximity to, and at both sides of, said large-diameter cylinder, said contact-drying cylinders having diameters less than the diameter of said large-diameter cylinder and being arranged outside the drying-wire loop, the web being carried on said drying wire over contact sectors b of each of said contact-drying cylinders, said sectors b having a magnitude greater than about 180.degree., and
at least one reversing suction roll arranged adjacent to a respective one of said contact-drying cylinders, said suction roll being arranged inside the drying-wire loop and having a diameter less than the diameter of said contact-drying cylinders, the web being carried on said drying wire over a contact sector c of said suction roll, said sector c having a magnitude greater than about 180.degree., and
at least one group of contact-drying cylinders having a twin-wire draw arranged at a rear end of the dryer section, said at least one group of cylinders having a twin-wire draw comprising contact-drying cylinders arranged in two rows, the web having open free draws between said two rows of contact-drying cylinders.

5 more elements

Dependencies are inferred from the claim text.