Curtain Coating Edge Guide Lubrication Stability
Solution Overview
Problem
Existing curtain coating devices face issues with curtain stability on edge guides, particularly at low coating color feed amounts, and problems related to the adhering and drying of coating color on the edge guide and suction channel, which disrupt the coating process.
Innovation Solution
The curtain coating device features a nozzle beam with edge guides having upper and lower ends with vertically extending flow surfaces, inclined towards each other to form a concave flow guide recess, including a protrusion for guiding the curtain, and adjustable lubrication and suction systems to maintain curtain stability and prevent coating color adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coating color feed amount is reduced to improve efficiency, then productivity increases, but curtain stability deteriorates
Solution Approach 1:
A lubrication liquid is introduced as an intermediary substance between the coating color curtain and the edge guide surface. This lubrication layer prevents direct contact and adhesion between the coating color and edge guide, maintaining curtain stability even at low feed amounts. The lubrication liquid acts as a mediator that reduces friction and prevents the coating color from adhering to the edge guide surface.
Solution Approach 2:
The invention changes the physical parameters of the interaction between coating color and edge guide by introducing a lubrication liquid layer. This alters the surface properties and friction characteristics, enabling the curtain to remain stable at lower feed amounts. The lubrication liquid modifies the boundary conditions between the coating color and edge guide surface.
2Manufacturing precision
If edge guide surface area is increased to improve curtain guidance, then manufacturing precision improves, but coating color adhesion increases
Solution Approach 1:
The lubrication liquid serves as an intermediary layer between the coating color curtain and the edge guide surface. This prevents direct contact and adhesion between the coating color and the edge guide, even when the edge guide has a large surface area for effective curtain guidance. The lubrication liquid eliminates the harmful adhesion effect while preserving the beneficial guidance function.
Solution Approach 2:
The invention extracts the harmful adhesion property from the edge guide system by introducing a lubrication liquid layer. This separates the useful function (curtain guidance through flow surfaces) from the harmful effect (coating color adhesion), allowing the edge guide to maintain its guidance function without suffering from adhesion problems.
3Reliability
If lubrication liquid supply is increased to prevent adhesion, then reliability improves, but device complexity increases
Solution Approach 1:
The lubrication liquid is supplied locally at specific points where the coating color curtain contacts the edge guide, rather than uniformly across the entire edge guide surface. This localized supply approach prevents adhesion at critical contact points while minimizing the overall complexity of the lubrication system. The lubrication is applied precisely where needed to maintain process reliability.
Solution Approach 2:
The lubrication system is designed to automatically maintain the lubrication liquid layer without requiring complex external control systems. The system self-regulates to ensure continuous lubrication at the edge guide, preventing adhesion and maintaining process reliability through self-sustaining operation.
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 design reduces the number of boundary surface encounters, ensures continuous lubrication, and effective suction, enhancing curtain stability and preventing coating color issues on the edge guide and suction channel, thus improving the coating process.
Implementation Method 1
a lubrication liquid (typically water) supply(s) onto edge guide
Implementation Method 2
a suction channel for collecting and removing edge area coating color and lubrication liquid
Data Source
Figure 1
Figure 2~4
Figure 5A~5C
AI summary
The invention relates to a curtain coating device for fiber machines, in particular for paper and board machines comprising a nozzle beam (10) with a nozzle lip (12) with an edge strip (11) for feeding the coating color curtain and edge guides (20) located along each edge of the nozzle lip (12) to control the width of the coating color curtain, which edge guide (20) comprises an upper end, a lower end, flow surfaces (22) extending in substantially vertical direction parallel and next to each other , a lubrication feed (24), additional lubrication feeds (26) and a suction opening (27). The flow surfaces (22) are inclined towards each other and form a flow guide recess (25) extending in vertical direction for an curtain edge guidance such that the form of the flow surfaces (22) with the flow guide recess (25) is concave and that in the flow guide recess (25) is located a protrusion (21) extending in the direction of the flow guide recess.