Comb Plate Sloped Teeth Prevent Roll Press Rewetting
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Solution Overview
Problem
Conventional roll presses in the pulp and paper industry face inefficiencies due to rewetting of pulp slurry as drainage channels rotate, leading to reduced pulp consistency, increased energy consumption, and maintenance needs, as filtrate flows back into the pulp mat, especially when channels approach the center line during rotation.
Innovation Solution
The implementation of a comb plate with sloped comb teeth extending through deck channels into drainage channels, and an anti-rewet plate configured to hold filtrate, directs filtrate effectively into drainage channels, reducing rewetting at various orientations of the drainage channels, including when they approach the center line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drainage channels are designed to rotate with the roll, then filtrate can be drained efficiently at certain orientations, but rewetting occurs when channels approach the center line during rotation
Solution Approach 1:
A comb plate with comb teeth is introduced as an intermediary component between the deck channel and drainage channel. The comb teeth act as a mediator to direct filtrate flow from the deck channel into the drainage channel, preventing filtrate from bypassing the drainage path and causing rewetting of the pulp mat when channels are at critical orientations during rotation.
Solution Approach 2:
The comb plate is positioned specifically at the interface between the deck channel and drainage channel, with comb teeth oriented to intercept filtrate flow at the critical location where rewetting occurs. This localized intervention addresses the specific problem area without requiring modification of the entire roll structure.
2Productivity
If roll speed is increased to improve production capacity, then more pulp can be processed per unit time, but rewetting effects are amplified due to faster rotation through critical orientations
Solution Approach 1:
The comb plate serves as a flow directing intermediary that ensures filtrate is efficiently channeled into drainage channels regardless of roll speed. By maintaining effective filtrate removal across all rotation speeds, the system can operate at higher speeds without the energy waste associated with rewetting and subsequent re-drying of the pulp mat.
3Device complexity
If drainage channel orientation is fixed, then structure is simple, but filtrate cannot be effectively drained when channels are at certain positions during rotation
Solution Approach 1:
The comb plate is designed with comb teeth that are angled to dynamically intercept filtrate flow as the drainage channels rotate through different orientations. The comb teeth's angled configuration allows them to effectively direct filtrate into drainage channels regardless of the channel's instantaneous position in the rotation cycle, maintaining high filtrate removal efficiency throughout the rotation.
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 solution significantly reduces rewetting, enhancing pulp consistency, decreasing energy requirements, and minimizing maintenance needs by ensuring more filtrate is directed into drainage channels, thus improving the efficiency of roll presses.
Implementation Method 1
Gravity generally assists filtrate drainage when a drainage channel rotates upwardly past the center line.
Implementation Method 2
the first end and the second end of the comb tooth define a slope configured to direct filtrate passing through the perforated plate through the deck channel into the drainage channel
Implementation Method 3
the first end and the second end define a concave slope configured to hold a volume of filtrate as the drainage channel rotates downwardly between the center line and the nadir of the roll
Implementation Method 4
the first end and the second end define a concave slope configured to hold a volume of filtrate
Data Source
AI summary
The problem of deck channel rewetting that occurs when a drainage chamber in a roll upwardly approaches a horizontal line extending past the horizontal diameter of the roll is solved by using a comb plate comprising at least one comb tooth engaging the perforated plate and extending through a deck channel to a drainage channel such that the at least one comb tooth has a slope configured to direct a slurry suspension from the perforated plate into the drainage channel.