CA1171650A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Device in the drying section of a paper machine
Assignee: Valmet Technologies Oy
•
Filing: 1980-11-19
•
Granted: 1984-07-31
•
Expires: 2000-11-19
Abstract
Abstract ABSTRACT OF THE DISCLOSURE An apparatus for use in the drying section of a paper machine. The drying section comprises two rows of drying clinders or rolls, one above the other. The web travels between these cylinders and rolls, meandering from one row to the other, all the time supported by a drying fabric. The web lies directly against the cylinder or roll surface in one row of cylinders or rolls and similarly the drying fabric is adjacent to the roll surface, while the web is on the outside, in the other row of cylinders or rolls. The apparatus comprises a suction box or a plurality of suction boxes, disposed to operate against the drying fabric. Said suction box or suction boxes extend sub-stantially over the entire length of the joint run of the web and the drying fabric from one cylinder to roll to the other. In addition, the suction of said suction box also extends into the wedge space between the drying fabric and the drying cylinder or equivalent roll shell and in at least the suction box on the entry side of the drying fabric and web or the respective suction boxes, there are suction apertures through which the subatmospheric pressure pre-vailing therein acts in said wedge space.
Inventors
- 👤 Timo Vedenpaa
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-07 19:36
CPC Classifications
D; D21; D21F; D21F5/00; D21F5/02; D21F5/04; D21F5/042
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
180 words
1, In a drying section of a paper machine including drying cylinders and a drying fabric loop arranged such that a first group of at least one of said cylinders are located outside of said drying fabric loop and a second group of at least one of said cylinders are located within said drying fabric loop so that the web runs in a closed draw in a joint run with and supported by said fabric from a cylinder of one group to a cylinder of the other group, said joint run defin-ing wedge-shaped spaces between said drying fabric and the shell of the drying cylinders, the improvement in which at least one suction box situated adjacent to a joint run of. said web and drying fabric, said suction box including suction apertures situated proximate to at least one of said wedge-shaped spaces to produce a suction effect mainly in said at least one of said wedge-shaped spaces, said at least one suction box thereby consituting means for producing a suction effect mainly in at least one of said wedge-shaped spaces.
Claim 2
Dependent Claim
180 words
1, In a drying section of a paper machine including drying cylinders and a drying fabric loop arranged such that a first group of at least one of said cylinders are located outside of said drying fabric loop and a second group of at least one of said cylinders are located within said drying fabric loop so that the web runs in a closed draw in a joint run with and supported by said fabric from a cylinder of one group to a cylinder of the other group, said joint run defin-ing wedge-shaped spaces between said drying fabric and the shell of the drying cylinders, the improvement in which at least one suction box situated adjacent to a joint run of. said web and drying fabric, said suction box including suction apertures situated proximate to at least one of said wedge-shaped spaces to produce a suction effect mainly in said at least one of said wedge-shaped spaces, said at least one suction box thereby consituting means for producing a suction effect mainly in at least one of said wedge-shaped spaces.
Claim 3
Dependent Claim
46 words
The machine of claim 1, wherein said suction effect produced in said wedge-shaped spaces by said suction effect producing means is substantially higher than a suction effect, if any, produced thereby in the region of said closed draw run of said web between said wedge-shaped spaces.
Claim 4
Dependent Claim
139 words
The machine of claim 1, wherein said at least one suction box includes a substantially closed, planar wall situated adjacent to a closed draw run of said web be-tween said wedge-shaped spaces, and wherein longitudinal seals are provided at each lateral side of said suction box in operative relation with and extending in the direction of the closed draw run of said web between said wedge-shaped spaces, and wherein transverse seals project from said closed wall proximate to said wedge-shaped spaces in operative rela-tion with and extending transverse to the direction of the closed draw run of said web between said wedge-shaped spaces, said transverse seals acting to inhibit the production of a subatmospheric pressure in a central region of the closed draw run, and said seals guiding said drying fabric at a distance from said substantially planar wall.
Claim 5
Dependent Claim
18 words
The machine of claim 3, wherein said suction apertures are situated in the region of said transverse seals.
Claim 6
Dependent Claim
62 words
The machine of claim 1, wherein said cylinders defining said wedge-shaped spaces each include a respective shell having a recessed surface, and wherein said suction effects produced in said wedge-shaped spaces are communicated into said recessed surfaces to facilitate maintenance of the web in contact with the outer surface of the drying fabric as it curves over a sector of the cylinder.
Claim 7
Dependent Claim
17 words
The machine of claim 5, wherein said recessed surface comprises a grooved surface in each said shell.
Claim 8
Dependent Claim
19 words
The machine of claim 6, wherein said grooved surface is formed by a profiled strip wound around said shell.
Claim 9
Dependent Claim
39 words
The machine of claim 5, wherein said recessed surface comprises axial grooves formed in each of said shells whereby the sector of said shell outside the sector thereof which is lapped by the drying fabrics communicates with ambient pressure.
Claim 10
Dependent Claim
39 words
The machine of claim 5, wherein said recessed surface comprises blind-drilled holes formed in each of said shells whereby the sector of said shell outside the sector thereof which is lapped by the drying fabrics communicates with ambient pressure.
Claim 11
Dependent Claim
52 words
The machine of claim 1, wherein said at least one suction box is partially defined by a curved wall having curved sealing strips provided on each of its lateral sides, said curved sealing strips spacing the surface of a cylinder lapped by said drying fabric a certain distance from said suction box..
Claim 12
Dependent Claim
45 words
The machine of claim l, wherein a transversely extending resilient sealing strip is provided on an edge of said at least one suction box to cooperate with a cylinder to prevent entry of air induced by the movement of said fabric into said suction box.
Claim 13
Dependent Claim
13 words
The machine of claim 3, wherein said transverse seals are rhombic in cross-section.
Claim 14
Dependent Claim
33 words
The machine of claim 3, wherein said suction box further includes a tube communicating with a space bet-ween said closed draw run of said web and said planar wall of said suction box.
Claim 15
Dependent Claim
19 words
The machine of claim l, wherein said suction box extends substantially over the entire breadth of said drying fabric.
Claim 16
Dependent Claim
21 words
The machine of claim 1, wherein said suction box is divided transversely into a plurality of compartments located in side-by-side relationship.
Claim 17
Dependent Claim
32 words
The machine of claim 15, wherein the vacuum produced in said compartments nearest to the lateral sides of the fabric is higher than the vacuum produced in other ones of said compartments.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.