Fibre Batt Drafting Oscillation for Acceleration Control
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Solution Overview
Problem
Existing facilities for forming fibre batts face challenges in reducing overspeeds and maximum accelerations while maintaining production speed, particularly when dealing with fibres that are difficult to draft, and there is a need to improve the homogeneity and thickness/area density profile of the batts exiting the crosslapper.
Innovation Solution
The facility incorporates control means to vary the thickness and area density of the fibre web as a function of time, using drafting mechanisms synchronized with the carding drum and doffer rollers to regulate the drafting action, which reduces maximum accelerations and overspeeds, and allows for increased production speed without increasing these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the production speed of the fibre batt is increased, then productivity is improved, but the maximum accelerations and overspeeds entering and exiting the crosslapper increase
Solution Approach 1:
The patent applies periodic variation to the drafting action through the drafting roller, which oscillates in speed in synchronisation with the carding drum and doffer rollers. This periodic drafting action creates corresponding periodic variations in web thickness and area density that compensate for the effects of increased production speed, allowing higher productivity without excessive accelerations and overspeeds in the crosslapper.
Solution Approach 2:
The patent introduces dynamic control of the drafting mechanism by making the drafting roller's speed variable and oscillating rather than constant. This dynamic adjustment of drafting intensity allows the system to adapt to different production speeds while maintaining controlled accelerations and overspeeds, resolving the contradiction between productivity and speed parameters.
2Productivity
If the production speed of the fibre batt is increased, then productivity is improved, but the homogeneity and thickness/area density profile of the batt deteriorate
Solution Approach 1:
The synchronous periodic oscillation of the drafting roller with the carding drum and doffer rollers creates regular variations in drafting intensity that produce corresponding periodic variations in web properties. This controlled periodic action ensures that thickness and area density profiles remain consistent and homogeneous even at increased production speeds, as the variations are predictable and can be compensated for in the crosslapper stacking process.
Solution Approach 2:
The system employs feedback control through the synchronous coordination of the carding drum, doffer rollers, and drafting roller. The drafting roller's oscillation is timed to match the periodic delivery of webs from the carding and doffering process, creating a feedback loop that maintains consistent web properties. This synchronised feedback mechanism ensures homogeneous batt quality regardless of production speed increases.
3Ease of operation
If drafting action is increased to handle difficult-to-draft fibres, then ease of operation is improved, but the maximum accelerations and overspeeds in the crosslapper increase
Solution Approach 1:
For difficult-to-draft fibres, the patent employs enhanced periodic drafting action through the oscillating drafting roller. The periodic variation in drafting intensity provides repeated gentle pulling actions that gradually work through resistant fibres without requiring excessive force or acceleration. This periodic approach makes operation easier with difficult fibres while avoiding the harmful effects of continuous high acceleration.
Solution Approach 2:
The dynamic oscillation of the drafting roller allows it to adapt its drafting force to the resistance of difficult-to-draft fibres. By varying the drafting intensity periodically rather than applying constant high force, the system can handle resistant fibres more easily while keeping accelerations and overspeeds within acceptable limits for the crosslapper.
Data Source
AI summary
A facility for forming a fibre batt, in particular nonwoven, provides a device for producing at least one fibre web, and a crosslapper which provides the fibre batt. The production device provides a carding drum and at least one doffer roller collecting the fibres on the drum and supplying the at least one web to at least one outfeed belt. The crosslapper provides an infeed belt for the introduction of the web in the crosslapper, which supplies the fibre batt formed of a stack of layers of the at least one web, and first control means of the profile of the thickness and/or of the area bulk density and/or of the bulk density of the web or of each web. A drafting means is arranged downstream of the outfeed belt of the production device and upstream of the infeed belt. Second control means may be provided to control drafting means.