Mixer Shaft Inversion for Loss-Free Startup Mixing

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Solution Overview

Problem

Existing mixers face issues with incomplete mixing and conditioning during startup, leading to increased back pressure and unnecessary disposal or recycling of product, as they struggle to ensure even distribution and processing of materials.

Innovation Solution

The design incorporates paddles with specific angled working and back surfaces, allowing for controlled mixing and conveying directions, where the paddle's working surface is inclined at a greater angle than the back surface, enabling efficient mixing without initial conveyance during startup, and reversing direction for effective product handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the mixer shaft is operated with the outlet closed during initial phase to increase back pressure, then mixing and conditioning is improved, but the mixer and material are subjected to undesirable pressure

Engineering Contradiction:
Improvemixing and conditioning qualityVSAvoidback pressure on mixer and material
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The invention reverses the conventional approach by initially rotating the mixer shaft in reverse direction (opposite to normal operation) to mix and condition the material without building back pressure. After the initial mixing phase, the shaft direction is switched to normal rotation to convey the material through the mixer. This inversion eliminates the harmful back pressure while maintaining effective mixing and conditioning.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If the mixer is simply started without special procedures, then operation is simple, but the product is initially insufficiently mixed and/or conditioned

Engineering Contradiction:
Improvemixer startup simplicityVSAvoidmixing and conditioning quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention implements periodic action by automatically switching the mixer shaft rotation direction in two phases: first rotating in reverse direction for mixing and conditioning, then switching to normal direction for material conveyance. This periodic direction change ensures both thorough mixing and proper material flow, eliminating the need for manual intervention or complex procedures while maintaining high mixing quality.

Inventive Principle:
Principle #19Periodic action

3Productivity

If conventional paddles convey material during startup rotation, then material moves through the mixer, but insufficient mixing and conditioning occurs

Engineering Contradiction:
Improvematerial conveyance speedVSAvoidmixing and conditioning quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention reverses the paddle function during startup by rotating the shaft in reverse direction, causing paddles to mix and condition material in place rather than convey it forward. After adequate mixing and conditioning is achieved, the rotation direction is switched to normal, at which point the paddles then convey the material through the mixer. This temporal separation of mixing and conveying functions ensures both are performed effectively.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2986365B1Conditioner, paddle rail and method for mixing
Publication Date: 2021.03.10 BUHLER AG
  • EP2986365B1 patent drawingFigure 1a~1c
  • EP2986365B1 patent drawingFigure 1d~1j
  • EP2986365B1 patent drawingFigure 1f~1g

AI summary

The invention relates to a paddle (30), a paddle rail (20), a mixer shaft (10) for a mixer (1), a mixer (1) and a method for mixing a product to be conditioned in a mixer (1) wherein, as the mixer (1) starts up, a product to be mixed is retained in a starting region of the mixer shaft (10), for instance, until the desired mixing or conditioning is achieved, so that loss-free start-up is made possible, that is to say disposal or recycling of the product when the mixer starts up becomes unnecessary.