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US 7,351,309 B2Granted
Roll in a paper or board machine and a dryer group in a paper or board machine
AssigneeMetso Paper, Inc.
InventorsMatti Kurki, Pekka Martikainen
Life of this patent
Estimating the term…
Abstract
A roll in a paper or board machine has a roll frame or center shaft (15) with bearings mounted at its ends and a groove-like surface structure (10). There is a contact between the surface structure and the center shaft so that an essentially closed structure is formed. The roll produces a vacuum that keeps the web attached to the outer surface of a fabric in the fabric wrap area of the roll circle by utilizing the boundary layer airflows of the surface structure flow and/or of the web. A dryer group has at least one contact dryer cylinder and at least one turning roll with a single fabric run arrangement.
Claims12
A dryer group in a paper or board machine comprising:
- a first contact dryer cylinder, a second dryer cylinder and a turning cylinder positioned therebetween;
- a single dryer fabric and a paper or board web arranged to travel over the first contact dryer cylinder with the paper or board web between the first contact dryer cylinder and the dryer fabric, and the paper or board web arranged to wrap around the turning cylinder supported by the dryer fabric to define a wrap area, and the dryer fabric and the paper or board web arranged to travel over the second dryer cylinder with the paper or board web between the second dryer cylinder and the fabric so that the paper or board web remains between the second dryer cylinder surface and the dryer fabric;
- wherein the dryer group turning cylinder is a roll comprising a groove-like surface structure and a center shaft or a roll frame, wherein there is contact between the surface structure and the center shaft or roll frame so that a closed construction is formed except for a portion of the roll used for threading a tail;
- wherein the turning cylinder roll is arranged with the dryer fabric to produce a vacuum that keeps the paper or board web attached to the dryer fabric at an outer surface within the wrap area of the turning cylinder;
- wherein the groove-like surface structure has portions forming grooves 18-155 mm deep and 6-10 mm wide, and wherein lands of a defined width are formed between the grooves, and wherein the ratio of groove width to land width is 0.6 to 2.0, and the ratio of groove width to depth is 2.25 or greater.
2 more elements
A dryer group in a paper or board machine comprising:
- a first contact dryer cylinder, a second dryer cylinder and a turning cylinder positioned therebetween;
- a single dryer fabric and a paper or board web arranged to travel over the first contact dryer cylinder with the paper or board web between the first contact dryer cylinder and the dryer fabric, and the paper or board web arranged to wrap around the turning cylinder supported by the dryer fabric to define a wrap area, and the dryer fabric and the paper or board web arranged to travel over the second dryer cylinder with the paper or board web between the second dryer cylinder and the fabric so that the paper or board web remains between the second dryer cylinder surface and the dryer fabric;
- wherein the dryer group turning cylinder is a roll comprising a groove-like surface structure and a center shaft or a roll frame, wherein there is contact between the surface structure and the center shaft or roll frame so that a closed construction is formed except for a portion of the roll used for threading a tail;
- wherein the turning cylinder roll is arranged with the dryer fabric to produce a vacuum that keeps the paper or board web attached to the dryer fabric at an outer surface within the wrap area of the turning cylinder;
- wherein the groove-like surface structure has portions forming grooves 18-155 mm deep and 6-10 mm wide, and wherein lands of a defined width are formed between the grooves, and wherein the ratio of groove width to land width is 0.6 to 2.0, and the ratio of groove width to depth is 2.25 or greater;
- and
- wherein the depth of the of the grooves is selected to produce a vacuum on the surface structure of the turning cylinder which is wrapped by the paper or board web which is at least about 200 Pa when the dryer group is operated at a machine speed greater than 1200 meters per minute.
4 more elements
A dryer group in a paper or board machine comprising:
- a first contact dryer cylinder, a second dryer cylinder and a turning cylinder positioned therebetween;
- a single dryer fabric and a paper or board web arranged to travel over the first contact dryer cylinder with the paper or board web between the first contact dryer cylinder and the dryer fabric, and the paper or board web arranged to wrap around the turning cylinder supported by the dryer fabric to define a wrap area, and the dryer fabric and the paper or board web arranged to travel over the second dryer cylinder with the paper or board web between the second dryer cylinder and the fabric so that the paper or board web remains between the second dryer cylinder surface and the dryer fabric;
- wherein the dryer group turning cylinder is a roll comprising a groove-like surface structure and a center shaft or a roll frame, wherein there is contact between the surface structure and the center shaft or roll frame so that a closed construction is formed except for a portion of the roll used for threading a tail;
- wherein the turning cylinder roll is arranged with the dryer fabric to produce a vacuum that keeps the paper or board web attached to the dryer fabric at an outer surface within the wrap area of the turning cylinder;
- wherein a pocket space is defined between the first contact dryer cylinder, the second dryer cylinder, the turning cylinder roll, and the fabric, and wherein a runnability component system is positioned within the pocket;
- wherein the runnability component system has a lower portion arranged so that air is drawn from the runnability component system in to the grooves of the turning cylinder roll;
- and
- wherein the pocket space is arranged to allow air from the grooves of the turning cylinder roll to pass out of the pocket space.
5 more elements
A method of controlling runnability in a dryer group of a paper or board machine having a first contact dryer cylinder, a second dryer cylinder and a grooved turning cylinder positioned therebetween, the method comprising the steps of:
- passing a paper or board web over the first contact dryer cylinder with the paper or board web between the first contact dryer cylinder and a dryer fabric;
- wrapping the paper or board web around the turning cylinder supported by the dryer fabric to define a wrap area;
- wrapping the dryer fabric and the paper or board web to travel over the second dryer cylinder with the paper or board web between the second dryer cylinder and the fabric so that the paper or board web remains between the second dryer cylinder surface and the dryer fabric;
- wherein the paper or board web and the fabric travel over a grooved turning cylinder having a groove-like surface structure and a center shaft or a roll frame, wherein there is contact between the surface structure and the center shaft or roll frame so that a closed construction is formed except for a portion of the roll used for threading a tail, and wherein the paper or board web and the fabric travel at a running speed of at least about 1200 meters per minute, and wherein the grooves are selected with a configuration to produce a vacuum of at least about 200 Pa where the paper or board web and the fabric travel over the grooved turning cylinder at said least about 1200 meters per minute;
- defining a pocket space between the first contact dryer cylinder, the second dryer cylinder, the turning cylinder roll, and the fabric, and positioning a runnability component system within the pocket;
- drawing air from the runnability component system into the grooves of the turning cylinder roll;
- and
- exhausting air from the grooves of the turning cylinder roll outwardly into the pocket space.
5 more elements
Dependencies are inferred from the claim text.