Drying Wire Runnability Component for Paper Machine Cylinder Seals
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Solution Overview
Problem
In fibre-web machines, the increasing speeds lead to runnability problems in single-wire draw drying cylinder groups, particularly due to wire bending and seal wear caused by negative pressure, resulting in reduced production efficiency and economic losses.
Innovation Solution
A runnability component is arranged with seals on the drying cylinder and reversing roll, minimizing the wire run length and using a single seal that bends parallel to the cylinder surface, combined with a flexible sealing arrangement, to reduce wire bending and seal wear, while maintaining negative pressure effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wire run length between drying cylinder and reversing cylinder is long, then the web has sufficient space to run smoothly, but the wire bends excessively and seals wear rapidly
Solution Approach 1:
The wire run between drying cylinder and reversing cylinder is segmented into two distinct zones: a first zone with substantial length for smooth web running, and a second zone with minimized length to reduce bending. This segmentation allows each zone to be optimized for its specific function, resolving the contradiction between runnability and seal durability.
Solution Approach 2:
Different sections of the wire run are given different qualities: the first zone maintains substantial length for web stability, while the second zone is minimized for reduced bending stress. This local differentiation allows the system to simultaneously achieve smooth web running and reduced seal wear.
2Duration of action of moving object
If the wire run length is minimized to reduce wire bending, then seal wear is reduced, but the web may not run smoothly
Solution Approach 1:
The wire run is divided into functional segments: the first zone provides substantial length for web runnability, while the second zone is minimized for reduced bending. This ensures both smooth web running and reduced seal wear are achieved in their respective zones.
Solution Approach 2:
Instead of minimizing the entire wire run length, the invention inverts the approach by maintaining substantial length in the first zone for runnability while minimizing only the second zone. This inverted segmentation resolves the contradiction by applying different length criteria to different functional zones.
3Stress or pressure
If multiple seals are used to confine negative pressure areas, then negative pressure effectiveness is improved, but device complexity and seal wear increase
Solution Approach 1:
The invention extracts the sealing function from multiple separate seals and concentrates it into a single seal arrangement at the reversing cylinder. This single seal confines the negative pressure area effectively while simplifying the overall device structure and reducing maintenance requirements.
Solution Approach 2:
Multiple sealing functions are merged into a single seal arrangement at the reversing cylinder. This consolidated approach maintains negative pressure effectiveness while reducing device complexity and the number of wear-prone components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This arrangement reduces wire bending, minimizes seal wear, and improves runnability by applying a strong suction effect between the wire and reversing cylinder, maintaining efficient negative pressure without directly affecting the wire, thus enhancing production efficiency and reducing economic losses.
Implementation Method 1
a runnability component is arranged with seals on the drying cylinder and reversing roll, minimizing the wire run length and using a single seal that bends parallel to the cylinder surface, combined with a flexible sealing arrangement, to reduce wire bending and seal wear, while maintaining negative pressure effectiveness
Data Source
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AI summary
The invention relates to a method in a dryer section of a fibre-web machine, in which at least one drying group employs single-wire draw in which a paper web (W) that is being dried runs on support of a drying wire (F) such that the drying wire (F) presses the web (W) on a drying cylinder (10) against heated cylinder surfaces, and the web (W) remains at the side of the outside curve of reversing cylinders (11) situated between drying cylinders (10). For the purpose of enhancing the runnability of the web (W), a runnability component (20) is placed in a pocket space (T) confined by two adjacent drying cylinders (10) and a reversing cylinder (11) situated between them and by the drying wire (F). In the method, the web (W) is passed from the drying cylinder (10) to the reversing cylinder (11) as a short transfer, the length of which transfer is 80 - 400 mm, and during the transfer a negative pressure effect produced by the runnability component (20) is applied to the web (W) and to the drying wire supporting it, which negative pressure effect is confined to be applied to the transfer of the web (W) by means of seals of the runnability component (20) against the surface of the drying cylinder (10) and against the surface of the reversing cylinder (11). The invention also relates to a device in a dryer section of a fibre-web machine, in which at least one drying group is a drying group which applies single-wire draw, and in which drying group a runnability component (20) is placed in a pocket space (T) confined by two adjacent drying cylinders (10) and a reversing cylinder (11) situated between them and by a drying wire (F). The drying cylinder (10) and the reversing cylinder (11) of the drying group are placed with respect to each other in such a way that the transfer of the web (W) from the drying cylinder (10) to the reversing cylinder (11) is short, that the length of the transfer is 80 - 400 mm, and during said short transfer a negative pressure effect is arranged to be applied by means of the runnability component (20) to the web (W) and to the drying wire (F) supporting it. For the purpose of confining an area of the negative pressure effect, seals of the runnability component (20) are placed so as to be directed against the surface of the drying cylinder (10) and against the surface of the reversing cylinder (11).