Adjustable Pulse Foil for Paper Machine Flocculation Control
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Solution Overview
Problem
Existing paper making machines face challenges in uniformly dispersing fibers in the slurry stock due to agglomeration, leading to non-uniform paper density, as previous foil devices lack sufficient adjustability to accommodate varying paper grades and processing speeds.
Innovation Solution
An adjustable pulse generating foil apparatus with a slideably coupled pulse generator that forms a nip with the forming fabric, allowing for movement and adjustment of the nip volume to reduce flocculation, utilizing an actuator for precise positioning of the pulse generator relative to the foil member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed-dimension channel foils are used to reduce flocculation, then fiber dispersion is improved for specific paper grades and speeds, but the device lacks adaptability to varying paper grades and processing speeds
Solution Approach 1:
The foil blade is designed with a flexible, wave-like profile that can dynamically adapt to different operating conditions. The flexible structure allows the foil to flex and adjust its effective geometry based on processing speed and paper grade requirements, eliminating the need for fixed-dimension channels that work for only specific conditions.
Solution Approach 2:
The invention changes the physical parameters of the foil blade by introducing flexibility and wave-like contours instead of fixed rigid channels. This allows the foil to present different effective geometries under varying operational parameters (speed, load, paper grade), thereby achieving adaptability across multiple operating conditions.
2Ease of manufacture
If fixed profile foil blades are used, then the structure is simple and easy to manufacture, but frequent replacement is needed to maintain quality across different paper grades
Solution Approach 1:
The flexible wave-like foil blade is designed to perform multiple functions across different operating conditions. A single universal foil design can effectively handle various paper grades and speeds by flexing to appropriate degrees, eliminating the need to manufacture and replace multiple specialized foil blades for different conditions.
Solution Approach 2:
The dynamic flexibility of the foil allows one blade design to adapt to multiple operational requirements, making the manufacturing process simpler while maintaining high productivity. The single flexible blade replaces what would otherwise require a inventory of multiple fixed-profile blades.
3Adaptability or versatility
If rigid adjustable angle foils are used, then some adaptability is achieved, but the trailing edge moves away from forming fabric reducing stock volume control
Solution Approach 1:
The invention uses a flexible thin film foil blade that can maintain contact with the forming fabric while adapting to different conditions. The flexibility allows the foil to conform to the fabric surface even when adjusted for different angles or speeds, preventing the trailing edge from detaching and losing control over the stock volume being processed.
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 apparatus effectively reduces flocculation by creating controlled movement in the slurry stock, enabling the production of high-quality papers across different grades and speeds without the need for frequent foil replacements.
Implementation Method 1
The foils disclosed by Johnson include machined grooves or channels in a surface of the foil to provide pressure pulses through the forming fabric which produces controlled agitation of the slurry stock.
Implementation Method 2
The Kallmes foil includes a trailing edge of the foil designed to fall away from the forming fabric, thus the foil does not force the stock back through the forming fabric. The Kallmes design has a fixed profile that may work well with one grade of paper and speed but not across all grades of paper and machines.
Data Source
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AI summary
A foil apparatus for a paper making machine includes a foil member postionable relative to forming fabric of a paper making machine, and a pulse generator coupled to the foil member, the pulse generator being adjacent to the foil member for forming a nip between the foil member and the forming fabric, the nip for creating movement in a slurry stock for reducing flocculation. A method of dewatering a forming fabric in a paper making machine includes moving a forming fabric carrying a slurry stock through a dewatering area of the paper making machine; positioning a foil apparatus for supporting the forming fabric, the foil apparatus having a foil member defining a work surface and a pulse generator coupled to the foil member adjacent the work surface; and forming a nip between the work surface and the forming fabric by positioning the pulse generator relative to the work surface.