Wet Web Transfer Belt Surface Structure for Hydroplaning Prevention
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Solution Overview
Problem
Existing belts for transferring wet webs in papermaking machines face issues such as skidding due to hydroplaning, damage from fluid pressurization, and groove marks being copied onto the wet web, limiting their speed and durability, especially at higher feed rates like 1,500 m/min.
Innovation Solution
A belt with a reinforcing fiber substrate buried in a water-impermeable resin layer, featuring a roll side layer with a surface roughness of 50-150 μm and a contact area percentage of 10-75% with rolls, incorporating batt fibers that protrude to create irregular surfaces, enhancing wear resistance and preventing hydroplaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a smooth belt surface is used, then the wet web can be transferred smoothly, but the belt experiences hydroplaning and skidding at high speeds
Solution Approach 1:
The belt surface is designed with local quality variation through protrusions and recesses, creating different surface characteristics in different areas. The protrusions provide friction grip to prevent hydroplaning, while the overall surface maintains wet web transfer capability, thus resolving the contradiction between smooth transfer and skidding resistance
Solution Approach 2:
The belt surface parameters are changed by creating a specific roughness profile with protrusions having defined heights and spacing. This parameter modification allows the surface to maintain contact with the wet web while preventing hydroplaning at high speeds, solving both the smoothness and reliability requirements
2Reliability
If grooves are formed on the belt surface to prevent hydroplaning, then skidding resistance improves, but groove marks are copied onto the wet web
Solution Approach 1:
The protrusions are designed with specific height limitations (0.1-2.0mm) and rounding at the tips to provide friction grip without creating sharp edges that would mark the wet web. This local quality control prevents groove marks while maintaining skidding resistance
Solution Approach 2:
The belt uses a composite structure combining a water-impermeable resin layer with a reinforcing fiber substrate. This composite design allows the surface to have the necessary roughness for skidding resistance while the underlying structure maintains dimensional stability to prevent mark formation on the wet web
3Productivity
If the belt operates at high feed rates (1,500 m/min), then productivity increases, but the belt suffers from fluid pressurization damage
Solution Approach 1:
The belt combines a water-impermeable resin layer with a reinforcing fiber substrate to create a composite structure that can withstand high fluid pressurization forces at feed rates up to 1,500 m/min while maintaining structural integrity and preventing damage
4Reliability
If the belt surface roughness is increased to prevent hydroplaning, then friction grip improves, but wear resistance decreases
Solution Approach 1:
The protrusion height is optimized within a specific range (0.1-2.0mm) to provide sufficient friction grip while limiting the height to reduce mechanical stress and wear. This parameter optimization balances friction grip requirements with wear resistance to extend belt service life
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 belt effectively prevents skidding and damage from fluid pressurization, maintains high-speed operation up to 1,500 m/min, and ensures no wet web marks on the paper, while improving wear resistance and durability.
Implementation Method 1
skids between the belt for transferring a wet web and various rolls, particularly a roll for controlling a travel position, caused by a hydroplaning phenomenon
Implementation Method 2
the belt for transferring a wet web is not damaged by fluid under pressurization
Implementation Method 3
a surface structure in which a percentage of a contact area with a roll per unit area is 10% to 75% and has a surface roughness Ra of 50-150 μm
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(c)
AI summary
Provided is a belt (20) for transferring a wet web, wherein any water mark does not appear on made paper even when a rate of feeding the belt (20) for transferring a wet web by a roll is high. The roll side layer surface (23) of the belt (20) for transferring a wet web has the surface structure in which the percentage of a contact area with the roll per unit area is 10% to 75% and a surface roughness Ra is 50-150 µm.