Sealing Runnability Component for Paper Machine Drying Cylinders
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Solution Overview
Problem
In paper or board machines, the detachment of the web from the drying wire at opening and closing nips leads to runnability issues, such as web breaks and pouches, due to insufficient sealing of the underpressure zone created by existing runnability components like blow boxes, resulting in energy inefficiency and paper waste.
Innovation Solution
A runnability component with a sealing surface and blow nozzle arrangement that creates a desired underpressure in the pocket space between drying cylinders using significantly less air, with optimized sealing distance and nozzle size, and adjustable blow velocity to ensure effective air flow and minimize leakage, allowing the component to be placed closer to the wire without damaging it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blow boxes are used to create underpressure zones to prevent web detachment, then web attachment to the drying wire is improved, but air leakage occurs at the sealing elements causing energy inefficiency
Solution Approach 1:
The invention changes the geometric parameters of the sealing element, specifically the ratio between the distance from the wire (A) and the nozzle slot size (B). By optimizing this ratio to be between 2-10, the sealing effectiveness is improved while reducing air leakage and energy consumption compared to conventional blow boxes.
Solution Approach 2:
The invention introduces a new dimensional relationship by defining the sealing effectiveness not just by the absolute distance from the wire, but by the ratio of this distance to the nozzle slot size. This dimensional change allows for optimized sealing performance across different scales and configurations.
2Reliability
If sealing elements are placed closer to the wire to improve sealing effectiveness, then underpressure zone sealing is improved, but the risk of damage to the sealing element or wire increases
Solution Approach 1:
By optimizing the ratio A/B between the distance from the wire and the nozzle slot size, the invention achieves effective sealing at safer distances from the wire, reducing the risk of damage to both the sealing element and the wire while maintaining underpressure zone effectiveness.
3Object-affected harmful factors
If blow nozzles are placed at a safety distance from the wire to prevent damage, then damage risk is reduced, but the underpressure zone is not sealed well enough causing energy waste
Solution Approach 1:
The invention resolves this contradiction by changing the critical parameter from the absolute distance A to the ratio A/B. This allows the sealing element to be placed at a safe distance from the wire while maintaining effective sealing through optimized nozzle slot sizing, thereby preventing both damage and energy waste.
4Object-affected harmful factors
If conventional blow boxes are used with large safety distances from the wire, then damage risk is reduced, but the effects of ejection blows remain insufficient
Solution Approach 1:
By optimizing the ratio A/B between the distance from the wire and the nozzle slot size, the invention achieves effective web attachment and underpressure zone sealing even when the sealing element is placed at a greater safety distance from the wire, thus preventing damage while maintaining reliability.
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 solution achieves a 35-40% energy savings by using less air to maintain underpressure, improving web attachment to the wire, reducing runnability problems, and allowing for integration with existing air systems, while maintaining efficient air removal and control of pressure zones.
Implementation Method 1
A blow nozzle is arranged inside the runnability component to blow air mainly along the sealing surface
Implementation Method 2
with which a desired underpressure is obtained in the pocket space between the drying cylinders
Implementation Method 3
the air layer to be blown from the nozzle slot travels along the sealing surface
Data Source
Figure 1
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Figure 3
AI summary
The invention relates to an arrangement and a method for sealing of a pocket space between drying cylinders (2, 3) in a paper machine or similar. In the method for sealing of the pocket space: a wire (5) is moved supported by the first and the second cylinder (2, 3, 4), a gap between the pocket space (15) and the space outside (24) it is sealed by a runnability component (6), which comprises at least a sealing surface (19, 22) and a blow nozzle (21 ) provided with a nozzle slot (26) of a size of 0.5-3.5 mm and elongated in the cross direction, the sealing surface (19, 22) is kept at a distance of 5-15 mm from the moving wire (5), air is blown with the blow nozzle (21 ) from a blow point (27) and along the sealing surface (22) towards a sealing point (16) and further via the sealing point (16) away (24) from the pocket space. The invention comprises also a runnability component (6) and a method for manufacturing the same. The parts of the runnability component are fastened together at least mainly without welding in the cross direction of the paper machine.