Paper Machine Forming Wire Tensioning Device with Linear Guides
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Solution Overview
Problem
Conventional tensioning devices for long forming fabrics in paper machines require multiple rollers and drives, leading to high operational and investment costs, and are limited in their ability to handle significant elongation and drive power transmission.
Innovation Solution
A tensioning device arrangement featuring a screen deflection roller and a movable screen tensioning roller with linear guides, allowing the forming fabric to wrap around both rollers in an S-shape, with a run angle of less than 40° and a strand angle of greater than 70°, enabling a larger clamping path and reduced need for multiple drives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If multiple tensioning devices and rollers are used to tension long forming fabrics, then the required tensioning path and drive power are achieved, but the device complexity and operational costs increase
Solution Approach 1:
The patent combines multiple tensioning functions into a single tensioning device that uses a deflecting roller and a tensioning roller working together. This single device can tension the entire length of the forming fabric, replacing what would traditionally require multiple separate tensioning devices and rollers, thereby reducing device complexity while maintaining the ability to handle long forming fabrics
Solution Approach 2:
The deflecting roller serves multiple functions: it guides the forming fabric, provides a surface for the fabric to wrap around to create tension, and works in conjunction with the tensioning roller to achieve the required tensioning path. This multi-functional design reduces the total number of components needed while still achieving the necessary tensioning effect for long forming fabrics
2Strength
If multiple rollers are used to deflect and tension the forming fabric, then the tensioning effect is achieved, but the effort involved in changing the forming fabric increases
Solution Approach 1:
By combining the deflecting and tensioning functions into a single integrated device with fewer moving parts, the patent simplifies the process of changing the forming fabric. With only one tensioning device to adjust and one set of rollers to manage, operators can change the fabric more quickly compared to systems with multiple separate tensioning devices that would each need to be adjusted independently
3Device complexity
If conventional tensioning devices are used, then simple construction is achieved, but the ability to transmit large drive power and handle significant elongation is limited
Solution Approach 1:
The patent uses curved surfaces of the deflecting roller and tensioning roller to create an S-shaped path for the forming fabric. This curved geometry allows the fabric to wrap around the rollers multiple times, effectively multiplying the tensioning path length and enabling the transmission of large drive power without requiring complex mechanical gearings or multiple drive units. The curvature also accommodates significant fabric elongation while maintaining tension
Data Source
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AI summary
The invention relates to an arrangement (1) for tensioning a forming wire (2) of a papermaking machine, in particular a Fourdrinier wire or a multilayer Fourdrinier wire, for producing multilayer fibrous webs, having a forming wire (2) that forms an endless wire loop, and a tensioning device (4) arranged in the return run (3) of the forming wire. The tensioning device (4) comprises a wire deflection roller (5) and a wire tensioning roller (6) that is arranged directly adjacent thereto and is displaceable relative to the wire deflection roller (5), and linear guides (7) which are arranged on both sides and on which the wire tensioning roller (6) is mounted so as to be displaceable in a displacement direction (8) over a displacement distance. The tensioning device (4) also comprises at least one linear-guide drive (9) for displacing the wire tensioning roller (6), wherein the forming wire (2) partially wraps around the wire tensioning roller (6) and the wire deflection roller (5) and forms a forming wire strand (10) between the wire tensioning roller (6) and the wire deflection roller (5), wherein one of the two rollers (5, 6) is arranged inside the wire loop and one is arranged outside the wire loop. The invention is distinguished by the fact that the linear guides (11) and the displacement travel are arranged and dimensioned such that the course of the forming wire strand (10) forms a strand angle (12) with the displacement direction of less than 40°, in particular less than 20°, preferably less than 10°, wherein this strand angle (12) becomes smaller during the tensioning operation.