Alternating Pressure Fibrous Material Impregnation
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Solution Overview
Problem
Existing methods for wetting wood chips and waste paper are inefficient, as they primarily focus on surface moistening and do not effectively introduce liquid into the fiber cavities, limiting the moisture content and elasticity of fibers, which in turn affects paper quality and processing efficiency.
Innovation Solution
A device that utilizes pressure changes to exploit the elasticity of fibers and fill their cavities with liquid, allowing for thorough wetting of wood chips or waste paper, including the use of vacuum and pressure systems to control the introduction of liquid into the fiber material, and features such as closable openings and a conveyor system for continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional surface wetting methods are used, then the process is simple, but the liquid does not effectively penetrate into fiber cavities, limiting moisture content and fiber elasticity
Solution Approach 1:
The patent applies periodic pressure changes (alternating positive and negative pressure cycles) to force liquid into fiber cavities. The ventilation line enables switching between negative pressure (vacuum) and positive pressure states, creating a pulsating wetting effect that penetrates deep into the fibrous material over time without requiring excessively high single-stage pressure.
Solution Approach 2:
The patent uses a ventilation line connected to pressure sources (vacuum pump and compressor/pressure vessel) to control pressure changes inside the housing. This pneumatic system enables rapid switching between vacuum and positive pressure states, allowing effective liquid penetration into fibers through controlled pressure differentials without complex mechanical injection systems.
2Quantity of substance
If pressure changes are used to penetrate liquid into fiber cavities, then wetting effectiveness improves, but processing time increases
Solution Approach 1:
The patent implements continuous cyclic pressure changes rather than single static pressure applications. The ventilation line allows rapid, repeated transitions between vacuum and positive pressure, maintaining continuous liquid penetration action. This continuous dynamic process achieves thorough wetting faster than static pressure methods would require.
Solution Approach 2:
By using periodic pressure cycles with the ventilation line, the system achieves cumulative liquid penetration effect. Each pressure cycle forces more liquid into previously inaccessible cavities, and the repeated cycling accelerates the overall wetting process compared to maintaining constant pressure for extended periods.
3Reliability
If wood chips are dried for storage, then storage stability improves, but wetting effectiveness and fiber elasticity decrease
Solution Approach 1:
The patent applies parameter changes by using alternating pressure states to fundamentally alter how liquid interacts with dried fibrous material. The vacuum phase opens collapsed fiber cavities, while the subsequent positive pressure phase forces liquid deep into these reopened cavities. This parameter switching enables effective wetting of previously dried material, restoring fiber elasticity without requiring the material to be stored in a wet state.
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 device enables quick and effective wetting of fibrous materials, increasing their moisture content, reducing processing time, and improving the bulk density and throughput of pulp, while also allowing for earlier filling of cooking liquor and reducing energy consumption.
Implementation Method 1
The interior of the housing (1) is vented to negative pressure
Implementation Method 2
the introduction of liquid, in particular water, into the entire volute of the wood chip. This means that not only the spaces between the fibers of the wood chips, but also the interior of the fibers are filled with a liquid
Implementation Method 3
which can be vented to overpressure more quickly and thereby further increase the effectiveness of the humidification
Implementation Method 4
the elasticity of the fibers and the change in the volume of the fiber cavities due to changing pressures are exploited
Data Source
Figure 1
Figure 2.1
Figure 2.2
AI summary
Apparatus for dampening fibrous material using the alternating pressure process with an airtight and vapour-tight housing (1), with a vacuum line (6), wherein a first directional valve (7) is provided in the vacuum line (6), the housing (1) has at least one closable opening (2, 21, 23) for loading and unloading the housing (1) and a ventilating line (11), and wherein a third directional valve (12) is provided in the ventilating line (11).