Thermal Spray Coated Roll Bands for Paper Machine Wear
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Solution Overview
Problem
Existing wire sections for producing and treating fibrous webs, such as paper or cardboard, face issues with wear and visibility of markings, particularly when producing graphic paper, and require frequent roll changes due to shrink fabric cover wear and limitations in cleaning agents.
Innovation Solution
Applying a thermal spray coating with a thickness of 0.5 to 2 mm to the outermost radial area of the roll's support structure, which includes a honeycomb design, to reduce wear and prevent marking visibility, while allowing for higher machine speeds and reduced downtimes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a honeycomb structure support structure is used on the roll, then noise reduction is achieved, but clear markings become visible in the fibrous web and wear increases on both the honeycomb structure and the wire
Solution Approach 1:
The invention applies a thermal spray coating specifically to the outermost radial area of the bands where they contact the wire. This creates a localized difference in surface properties - the coated area has different friction and wear characteristics compared to the uncoated areas, allowing the coated surface to prevent marking while maintaining the honeycomb structure's noise reduction benefits
2Manufacturing precision
If a shrink fabric cover is used on the roll, then water discharge equalization and avoidance of perforated shadow markings are achieved, but frequent roll changes are required due to wear and unplanned downtime occurs due to damage
Solution Approach 1:
The invention creates a composite structure by applying a thermal spray coating (such as ceramic or metal-based materials) onto the band surface. This composite material system combines the structural integrity of the band with the wear-resistant and marking-preventive properties of the coating, significantly extending roll service life while maintaining water discharge equalization capabilities
3Quantity of substance
If a regular basic drilling pattern with sharp edges is used on the roll, then drainage openings are provided, but increased wear occurs on both the roll and the wire due to reduced bearing surfaces
Solution Approach 1:
The invention fundamentally changes the surface parameters of the bands by applying a thermal spray coating that modifies friction coefficients, wear resistance, and surface smoothness. This parameter change allows the bands to maintain effective contact with the wire while dramatically reducing wear on both components, even with the regular drilling pattern providing adequate drainage
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
The thermal spray coating significantly reduces wear on the roll and wire, enabling the production of a broader range of paper grades with improved runnability and reduced maintenance, including fewer roll changes and unplanned downtimes.
Implementation Method 1
the belts are provided with a thermal spray coating at least in their outermost radial area, in which they come into contact with the wire at least temporarily
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
In a sieve part for a fibrous sheet processing machine with roller(s) (2) and sieve(s) (4) guided over part of the roller periphery, the roller casing (3) having radial openings (5) and being enclosed in a supporting construction assembled from strips (7.2) on end in the casing radial direction, the strips (at least in the outermost, sieve-contacting radial region (10)) have a thermally sprayed coating (11) with sieve facing radius (R) at least 0.05 (especially at least 0.3) mm. An independent claim is included for the production of the roller (2) (specifically a forming or sieve suction roller) for use in the sieve part, by applying the thermally sprayed coating (11) as above.