Curtain Starch Coating Press Gap With Heated Crowned Rollers
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Solution Overview
Problem
Existing coating technologies for paper and cardboard machines face inefficiencies in applying coating mediums, particularly starch, due to high manufacturing costs, uneven distribution, high energy consumption, and limited solids content, leading to suboptimal strength properties and economic inefficiency.
Innovation Solution
A device utilizing a curtain applicator with adjustable crowning and heated rollers to apply high solids content starch indirectly through a press gap, ensuring precise control and penetration, reducing energy consumption and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a curtain applicator with adjustable crowning and heated rollers is used to apply high solids content starch indirectly through a press gap, then the penetration and uniform application of starch is enhanced, but the device complexity increases
Solution Approach 1:
The device is divided into distinct functional modules: a curtain applicator for starch distribution, heated rollers for temperature control and starch activation, and a press gap for penetration. This segmentation allows each component to be optimized independently while maintaining overall system precision and uniformity in starch application.
Solution Approach 2:
The crowning of the rollers is made adjustable, allowing dynamic adaptation of the pressure distribution across the press gap. This dynamic adjustment capability enables precise control over starch penetration and uniformity without requiring overly complex fixed-geometry designs, resolving the contradiction between precision and complexity.
2Strength
If high solids content starch is applied indirectly through a press gap with heated rollers, then the strength properties of paper and cardboard are improved, but the energy consumption increases
Solution Approach 1:
The heated rollers induce phase transitions in the starch by raising its temperature, which activates the starch and enhances its binding properties. This thermal phase transition improves the strength properties of the paper and cardboard while allowing the process to occur continuously without excessive energy input, as the heat is applied locally and efficiently during the pressing operation.
3Manufacturing precision
If curtain applicators with adjustable crowning are used, then the uniform application and penetration of starch is enhanced, but the manufacturing precision requirements for nozzle parts increase
Solution Approach 1:
The adjustable crowning feature allows the system to compensate for variations in nozzle geometry and starch flow characteristics dynamically during operation. This reduces the stringency of manufacturing tolerances for the nozzle parts, as the system can self-adjust to achieve uniform starch application, thereby easing manufacturing requirements while maintaining high precision in the final application.
Solution Approach 2:
The system changes operational parameters such as roller temperature, pressing force distribution (via adjustable crowning), and starch delivery rate to optimize uniform application. By controlling these parameters dynamically, the system achieves high manufacturing precision in starch application without requiring extremely tight tolerances on the physical nozzle parts themselves.
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
Enhances the penetration and uniform application of starch, improving the strength properties of paper and cardboard while reducing energy consumption and manufacturing efforts, achieving higher economic efficiency.
Implementation Method 1
at least one heated application roller (7)
Implementation Method 2
press gap N for generating hydraulic pressure as the web of material 13 passes through the press gap N
Implementation Method 3
the at least one press gap N is equipped with at least one heated application roller (7) in order to increase the penetration of the application medium (2.1, 2.2) into the material web (13)
Data Source
Figure 1
Figure 2
AI summary
Device for applying a coating medium (2.1, 2.2), in particular starch, to at least one side of a running material web (13), in particular a paper or cardboard web, by means of at least one curtain coating unit (1.1, 1.2) with a dispensing nozzle (14.1, 14.2) and at least one press gap (N) following the curtain coating unit (1.1, 1.2) to generate hydraulic pressure as the material web (13) passes through a press gap (N) formed by two rotating press rollers, which allows the coating medium (2.1, 2.2) to penetrate the material web (13), wherein, to increase the penetration of the coating medium (2.1, 2.2) into the material web (13), the at least one press gap (N) is equipped with at least one heated coating roller (7, 8) as a press roller, and at least one of the two press rollers (8) is designed with a fixed or adjustable crown (16) for adjustment a line load in a range of 20 to 200 kN/m.