Two-Stage Pulverizing Apparatus for Fine Paper Powder Production
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Solution Overview
Problem
Existing methods for producing fine paper powder struggle with achieving high yield and efficient mass production, particularly when dealing with paper powders that have a maximum particle diameter of 100 μm or less, and those with resin layers, which often result in defects and poor pattern transferability in injection molding.
Innovation Solution
A pulverizing apparatus with a specific configuration, including stationary and rotary blades with a controlled gap and high peripheral speed, combined with a screening system and an accumulation chamber for efficient discharge, along with a two-step pulverization process using a grinding type pulverizer for further refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single-step pulverization using vertical roller mill or drug research mill is used, then the process is simple, but the processing capability and production efficiency are insufficient for mass production demands
Solution Approach 1:
The pulverization process is divided into multiple stages with different pulverizers. The first pulverizer (vertical roller mill or drug research mill) performs initial pulverization to reduce paper to fine powder (25-50 μm). The second pulverizer (impact-type pulverizer with rotary blades) performs final fine pulverization to achieve maximum particle diameter of 100 μm or less. This segmentation allows each stage to be optimized for its specific function, achieving mass production capability while maintaining process manageability.
Solution Approach 2:
The impact-type pulverizer introduces dynamic high-speed rotation (19-30 m/sec peripheral speed) to achieve fine pulverization through impact forces. The rotary blades rotate at high speed to strike paper particles against stationary blades, creating dynamic pulverization that complements the static grinding of the first stage. This dynamic approach significantly enhances processing capability for mass production.
2Manufacturing precision
If paper powder with large particle size is used in injection molding, then the resin composition can accommodate larger particles, but the paper powder disrupts resin flow and causes filling failures and poor pattern transferability
Solution Approach 1:
The invention严格控制 the maximum particle diameter of paper powder to 100 μm or less through the two-stage pulverization process. This parameter control ensures that paper particles are small enough not to disrupt resin flow during injection molding, preventing filling failures and achieving good pattern transferability. The first stage produces 25-50 μm powder, and the second stage ensures maximum particles do not exceed 100 μm.
3Manufacturing precision
If the space between stationary blades and rotary blades is large, then the pulverizer structure is simple and easier to manufacture, but the pulverization effectiveness is limited to several millimeters only
Solution Approach 1:
The impact-type pulverizer features a localized narrow gap region (0.1-0.5 mm) between stationary and rotary blades where the actual fine pulverization occurs. This localized quality control allows the majority of the pulverizer structure to remain simple and easy to manufacture, while only the critical blade interaction zone requires precise gap control. The high-speed rotation (19-30 m/sec) in this localized region achieves the required 100 μm or less particle size.
4Productivity
If high-speed rotation is used to achieve fine pulverization, then the processing capability improves, but the energy consumption increases
Solution Approach 1:
The first pulverizer (vertical roller mill or drug research mill) performs preliminary pulverization to reduce paper to fine powder with 25-50 μm average particle diameter before the second pulverizer. This preliminary action significantly reduces the energy required in the second stage, as the impact-type pulverizer only needs to achieve the final 100 μm or less specification rather than starting from coarse paper. The high-speed rotation (19-30 m/sec) is applied only to this pre-conditioned material, optimizing energy efficiency.
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 apparatus achieves high yield and efficient production of fine paper powder with a maximum particle diameter of 100 μm or less, effectively addressing the challenges of resin layer processing and maintaining energy efficiency.
Implementation Method 1
a plurality of rotary blades fixed to the rotary shaft so as to oppose the stationary blades, and tip ends thereof having space of 0.1 mm or more to 0.5 mm or less between tip ends of the stationary blades
Implementation Method 2
a pulverization chamber which has a plurality of stationary blades at an inner peripheral surface thereof, the plurality of stationary blades extending in an axial direction and being separated by intervals in a peripheral direction
Implementation Method 3
a screen arranged inside or outside the pulverization chamber and having a mesh opening of 130 μm or more to 400 μm or less
Data Source
AI summary
Provided is a pulverizing apparatus (100) including a pulverization chamber (110) provided with a plurality of stationary blades (111) on an inner peripheral surface, a rotary shaft (120) rotatably supported by the pulverization chamber (110), a plurality of rotary plates (130) fixed to the rotary shaft (120) and separated with intervals in the horizontal direction, and having a plurality of a rotary blades (131) on an outer peripheral surface, tip ends of the rotary blades (131) having space of 0.3 to 0.5 mm between tip ends of the stationary blades (111), a paper powder feed port (140) to which paper powder is fed, a rotation driving unit (150) which rotates the rotary shaft (120) so that a peripheral speed of the tip ends of the rotary blades (131) is 19 to 30 m/sec, and a screen (160) arranged inside the pulverization chamber (110) having mesh openings of 130 to 400 μm.