Conveyor Pipe Widening for Homogeneous Wet Gluing of Wood Fibres
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Solution Overview
Problem
The existing wet gluing method for wood fibres in the 'blow line' process faces issues with non-homogeneous adhesive application, leading to shading effects, clogging, and reduced throughput due to high fibre stream speed and pressure differences, which results in inefficient adhesive use and potential fibre backflow.
Innovation Solution
The conveyor pipe widens by up to 30% at the start of the gluing zone to reduce fibre stream speed, allowing for more homogeneous gluing with multiple nozzles, and then narrows behind the last nozzle to increase speed for efficient fibre transport to the dryer, using propellant effectively and reducing adhesive consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cross section of the conveyor pipe is reduced to decrease droplet size, then droplet size is reduced, but the shading effect is intensified and throughput is reduced
Solution Approach 1:
The conveyor pipe cross-section is segmented into two distinct zones: a reduced cross-section gluing zone for effective adhesive atomization and a full cross-section transport section for maintaining high throughput. This spatial segmentation allows each zone to optimize its function without compromising the other.
Solution Approach 2:
The pipe cross-section is varied locally along the fibre stream: reduced at the gluing location for optimal glue atomization, and full elsewhere to maintain high throughput. This local adaptation of geometry allows simultaneous optimization of gluing quality and production capacity.
2Productivity
If the fibre stream speed is increased to maintain throughput, then productivity is improved, but the adhesive application becomes non-homogeneous and clogging occurs
Solution Approach 1:
The conveyor pipe cross-section is dynamically adjusted along the fibre stream path, being reduced only at the specific gluing location and full elsewhere. This dynamic geometric variation allows the system to maintain high overall throughput while creating localized conditions for homogeneous adhesive application.
Solution Approach 2:
The reduced cross-section pipe section acts as an intermediary element that temporarily constricts the fibre stream only at the gluing zone, enabling effective adhesive application without permanently reducing the overall transport capacity of the system.
3Manufacturing precision
If the cross section is reduced to improve gluing homogeneity, then adhesive distribution is improved, but counter pressure increases and throughput is reduced
Solution Approach 1:
The pipe is segmented into a reduced cross-section gluing zone and full cross-section transport zones. This segmentation confines the pressure increase to only the small gluing section, allowing effective adhesive application without permanently elevating pressure throughout the entire transport system.
Solution Approach 2:
The pipe cross-section parameter is changed locally at the gluing zone to create optimal conditions for adhesive application, while the rest of the system maintains its original parameters for high throughput. This localized parameter change minimizes the impact on overall system pressure and flow.
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 approach ensures better fibre wetting, reduces shading effects, and enhances adhesive efficiency by maintaining a lower pressure in the gluing zone, allowing for improved gluing and reduced adhesive usage while maintaining high throughput.
Implementation Method 1
the conveyor pipe (1) widens by up to 30% at the start of the gluing zone (BZ) so as to reduce the speed of the fibre stream
Implementation Method 2
it narrows behind the last nozzle (DL) so as to increase the speed of the fibre stream again
Implementation Method 3
by which the fibres in the calmed fibre stream are glued with adhesive
Data Source
AI summary
A method for wet gluing of wood fibers, which have been defibrated in a refiner from wood comminuted into chips, in order that these chips, following wet gluing in a gluing zone, can be dried in a dryer, then spread, in a spreading arrangement, to form a fiber mat and pressed, in a hot press, to form a wood-material panel. The wood fibers are transported into the gluing zone, within a conveying tube, in a stream of saturated steam. In order to calm the fiber stream, the conveying tube widens at the start of the gluing zone, within which a plurality of gluing nozzles are situated, as a result of which the speed of the fiber stream is reduced before the first gluing nozzle has been reached, the fibers in the calmed fiber stream are glued with adhesive by the gluing nozzles, and then are fed to the dryer.