Curtain Coating Distribution Chamber with Replaceable Lip Elements
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Solution Overview
Problem
Existing curtain sizing and coating systems for fiber webs are limited in their ability to handle different types of treatment substances with varying properties, such as viscosity and surface tension, often requiring the entire system to be replaced, and suffer from uneven cross-directional application profiles.
Innovation Solution
A curtain sizing or coating method and device that includes a distribution chamber with adjustable flow means, such as by-pass lines and replaceable lip elements, allowing for control of the treatment substance profile without altering the outer shape of the chamber, enabling application to both sides of the fiber web with opposite feed ends and using replaceable inserts to adjust inner dimensions for different substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the entire treatment system is replaced to handle different treatment substances, then the system can accommodate various substances with different properties, but the cost and complexity increase significantly
Solution Approach 1:
The treatment system is segmented into modular components: the distribution chamber remains fixed while the lip elements and inserts are replaceable modules. This allows only the necessary parts to be changed when handling different treatment substances, rather than replacing the entire system.
Solution Approach 2:
The distribution chamber is designed with universal compatibility to work with multiple types of treatment substances (sizing agents, coating colors, pigmented sizing agents) by simply changing the lip elements and inserts, making the main chamber a multi-functional component.
2Device complexity
If the feed opening is located in the middle of the distribution chamber, then the system structure is simplified, but the cross-directional application profile becomes inclined and uneven
Solution Approach 1:
The lip elements are designed with varying heights across their width to create different local flow characteristics. This local variation in lip element geometry compensates for the middle-fed configuration, ensuring uniform treatment substance distribution across the web width despite the simplified central feed structure.
3Manufacturing precision
If the slot opening is made narrower and longer to decrease profile inclination, then the application profile improves, but the slot opening becomes expensive, difficult to clean, and easily clogging
Solution Approach 1:
The lip elements are extracted as separate, replaceable components from the distribution chamber structure. This allows the lip elements to be optimized for performance while being easily removable for cleaning and replacement, avoiding the maintenance problems associated with integrated narrow slot openings.
4Device complexity
If a fixed treatment system is used, then the system structure is simple, but it cannot adapt to treatment substances with substantially different properties
Solution Approach 1:
The system incorporates dynamic adaptability through replaceable lip elements and inserts that can be changed based on the treatment substance properties (viscosity, surface tension). This allows the system to adapt its geometry and flow characteristics dynamically to match different substance requirements while maintaining a simple fixed distribution chamber structure.
Data Source
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AI summary
The invention relates to a method of treating a fiber web, in which method the fiber web (W) is treated in a treatment system (10), in particular coated by curtain coating or sized by curtain sizing, which treatment system (10) comprises at least one curtain application device (20) and two treatment rolls (30) between of which treatment rolls (30) a treatment nip (N) is formed, in which method at least one curtain (C) of a treatment substance is provided by the application device (20). In the method an application device (20), which comprises a distribution chamber (21), at least one feed opening (20F), at least one flow-through (20FT) and a lip opening (24), is used to provide the curtain (C) of the treatment substance and in the method profile of the applied treatment substance in cross direction of the fiber web (W) i.e. in longitudinal direction of the application device (20) is controlled by at least one means configured to adjust flow of the treatment substance in the distribution chamber (21). The invention also relates to a treatment system for treatment of a fiber web (W), in particular a coating system for curtain coating or a sizing system for curtain sizing, which treatment system (10) comprises at least one curtain application device (20) and two treatment rolls (30) between of which treatment rolls (30) a treatment nip (N) is formed. The application device (20) comprises a distribution chamber (21), at least one feed opening (20F), at least one flow-through (20FT) and a lip opening (24) and the treatment system (10) further comprises at least one means configured to adjust flow of the treatment substance in the distribution chamber (21) to control the profile of the treatment substance applied in cross direction of the fiber web (W) i.e. in longitudinal direction of the application device (20).