Straw Knot Crushing for High-Density Blow-In Insulation
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Solution Overview
Problem
Current methods cannot produce an insulating material from straw that can be blown into cavities using conventional blowing machines to a suitable density of at least 90-130 kg/m³, as the structural resistance of straw knots limits compaction.
Innovation Solution
The method involves squeezing straw between counter-rotating rollers to crush the knots, followed by shredding to maintain fiber lengths, allowing for the production of an insulating material that can be compressed to over 100 kg/m³ when blown in, using a device with a squeezing device and downstream comminution to process the straw efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straw is chopped alone, then processing is simple, but the insulation material cannot be injected to suitable compaction (at least 90-130 kg/m³)
Solution Approach 1:
The patent applies segmentation by dividing the straw processing into two distinct stages: chopping (segmenting the straw into smaller pieces) followed by knot crushing (breaking down the resistant knot structures). This two-stage segmentation approach allows each process to be optimized independently, achieving both ease of manufacture and suitable compaction density.
Solution Approach 2:
The patent employs preliminary action by performing chopping before knot crushing. The initial chopping prepares the straw by reducing its overall size and making the knots more accessible, which facilitates the subsequent crushing process and enables achieving target compaction density with conventional injection machines.
2Device complexity
If straw knots are not crushed, then processing is simpler, but the material resists compaction to over 100 kg/m³ when blown in
Solution Approach 1:
The patent applies the taking out principle by specifically targeting and extracting the problematic knot structures from the straw material. The knot crusher is designed to selectively crush these resistant nodes while leaving the rest of the straw structure relatively intact, removing the primary obstacle to compaction without unnecessarily complicating the overall processing system.
Solution Approach 2:
The patent employs parameter changes by modifying the physical state of the straw knots through mechanical crushing. The knot crusher applies controlled mechanical force to change the structural parameters of the knots, breaking them down into smaller, more compressible fragments that can be compacted to the required density when blown into cavities.
3Productivity
If straw is shredded extensively, then compaction is improved, but fiber lengths are reduced compromising insulating properties
Solution Approach 1:
The patent applies local quality by applying different levels of mechanical processing to different parts of the straw. The knot crusher specifically targets the knot regions with intensive crushing action, while the overall shredding is kept moderate to preserve fiber length. This localized approach ensures high compaction density at the knot locations without excessively reducing the insulating fiber structure.
Solution Approach 2:
The patent employs partial action by applying crushing force selectively to the knots rather than uniformly shredding the entire straw material. This partial action on the problematic knot structures achieves the necessary compaction improvement while avoiding excessive shredding that would compromise the insulating fiber lengths and overall thermal performance.
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 enables the production of an insulating material that can be effectively blown into cavities with conventional machines, achieving densities between 100 and 150 kg/m³, while preserving the beneficial properties of straw as an insulating material.
Implementation Method 1
the straw is squeezed between at least two opposing, counter-rotating rollers... wherein the knots of the straw are squeezed during the squeezing
Implementation Method 2
a suction device (15) for conveying the straw through the crushing device
Data Source
Figure 1
Figure 2~4
AI summary
Process for manufacturing a blow-in insulation material (2) made of straw (3), comprising a processing step in which the straw (3) is crushed between rolls (10, 11, 2) in a crushing apparatus (7), a crushing nip in the crushing apparatus (7) being selected in such a way that the straw (3) nodes are crushed during the crushing operation.