Coating Applicator Roller Sealing for Lateral Fluid Leakage

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Solution Overview

Problem

Existing coating technologies suffer from lateral leakage of viscous fluids, such as paint or glue, due to misalignment of adjacent rolls caused by manufacturing tolerances, leading to maintenance issues and contamination risks.

Innovation Solution

A coating unit design featuring a first cylinder and a second cylinder forming an application gap, with side walls that form sealing surfaces matching the roller surfaces to prevent lateral leakage, ensuring a fluid storage space is sealed against both axial and radial passages, using plastic or metal components for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If side walls are pressed onto roller end faces by compression springs to seal the fluid storage space, then sealing effectiveness is improved, but device complexity and maintenance effort increase

Engineering Contradiction:
Improvesealing effectivenessVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the sealing function from a complex spring-loaded side wall system and implements it through a simpler groove-and-lip structure integrated into the roller design, eliminating the need for separate compression springs and complex adjustment mechanisms while maintaining effective sealing

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sealing structure is merged with the roller body itself - the groove is formed in the roller and the lip is part of the roller assembly, creating an integrated sealing solution that eliminates separate sealing components and reduces overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If side walls are positioned to seal against roller end faces, then lateral leakage is prevented, but manufacturing precision requirements increase due to tolerance variations in roller position and width

Engineering Contradiction:
Improvelateral leakageVSAvoidmanufacturing precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent changes the sealing approach from relying on precise dimensional parameters (roller width and position tolerances) to a geometric configuration where the groove and lip create a self-adjusting seal that accommodates parameter variations, effectively decoupling sealing performance from manufacturing precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible lip in the groove configuration can dynamically adjust its position and contact pressure to maintain sealing effectiveness despite variations in roller positioning and dimensional tolerances, making the seal adaptive rather than rigid

Inventive Principle:
Principle #15Dynamics

3Quantity of substance

If a fluid storage space is formed between rollers with side walls, then fluid supply to the coating cylinder is improved, but fluid leakage through lateral gaps increases

Engineering Contradiction:
Improvefluid supplyVSAvoidfluid leakage
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent uses a flexible lip (thin film structure) that conforms to the roller surface and creates an effective seal against lateral leakage while allowing the fluid storage space to maintain adequate fluid supply to the coating cylinder through the controlled gap configuration

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4442371B1Applicator for applying a fluid to a substrate and machine with such an applicator
Publication Date: 2025.07.23 KOENIG & BAUER AG
  • EP4442371B1 patent drawingFigure 1
  • EP4442371B1 patent drawingFigure 2
  • EP4442371B1 patent drawingFigure 3

AI summary

The invention relates to an applicator (01) for coating a substrate (B) with a fluid (L) comprising a first cylinder (02) which forms an application gap with a second cylinder (03) in which the substrate (B) to be guided through the application gap and coated is or can be supplied with the fluid (L) on the side facing the first cylinder (02), wherein the first cylinder (02) can be supplied with the fluid (L) to be applied on its outer surface directly or indirectly by means of a feed device (04).The feed device (04) comprises a first roller (06) and a downstream second roller (07), which form a first gap (11) between them with a gusset above it, wherein a fluid storage chamber (12) is provided in the gusset between two axially spaced side walls (13), and wherein the respective side wall (13) laterally delimiting the fluid storage chamber (12) comprises a sealing surface (18.1) facing the roller shell surface towards one of the two rollers (07; 06) forming the first gap (11), which has a contour corresponding to the roller shell surface and together with the roller shell surface forms a seal against lateral passage of the fluid (F).The feed device (04) has a third roller (09) downstream of the second roller (07) forming a second gap (21) with the second roller (07), wherein the side wall (13) has a sealing surface (18.1; 18.3) with a contour corresponding to the roller curvature and interacting with the roller shell of the second roller (07) as a seal above the second gap (21) and/or a sealing surface (19.3) facing the end face of the third roller (08) and interacting with the end face of the ball of the third roller (08) as a seal above the second gap (21).