Coaxial Mill Feed Unit With Rotary Bearing

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Solution Overview

Problem

Existing mill designs require time-consuming and costly setup and maintenance processes due to the need to dismantle large parts for sieve replacement, blockage clearance, and cleaning, which affects process reliability and increases downtime.

Innovation Solution

A feed unit with an annular rotary bearing allows for relative rotation between the feed tube and other mill components, enabling easier material flow and reducing the need for complex setups, while a compact design minimizes mechanical interfaces and energy losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If large parts of the mill are dismantled for sieve replacement or blockage clearance, then maintenance and setup can be performed, but downtime increases and process reliability decreases

Engineering Contradiction:
Improvesieve replacementVSAvoiddowntime
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The mill is divided into separable modules: the sieve unit can be independently removed from the housing without dismantling the entire mill structure. This segmentation allows the sieve unit to be replaced as a separate component, significantly reducing downtime while maintaining full access for maintenance operations.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If additional consoles and sliding or pivoting devices are added to bring mills into working position, then setup flexibility is improved, but device complexity increases

Engineering Contradiction:
Improvesetup flexibilityVSAvoidmechanical interfaces
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of using complex sliding or pivoting devices to adjust the mill position, the invention inverts the approach by making the sieve unit itself adjustable and removable. The sieve unit can be tilted or removed independently while the main mill housing remains stationary, achieving setup flexibility without adding mechanical complexity to the overall system.

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

3Power

If the drive rod is positioned upstream in the direction of flow, then kinetic energy supply is improved, but product flow is impeded

Engineering Contradiction:
Improvekinetic energy supplyVSAvoidproduct flow
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The drive rod and its associated drive mechanism are extracted from the main product flow path. The drive rod is positioned in a separate chamber or access area, allowing it to be operated independently without obstructing the material flow through the mill. This separation maintains full kinetic energy supply to the sieve unit while ensuring uninterrupted product flow.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If the angular gear and sieve obstruct downward product discharge, then grinding action is maintained, but maintenance accessibility is reduced

Engineering Contradiction:
Improvegrinding actionVSAvoidmaintenance accessibility
Core Design Contradiction:
ProductivityVSEase of repair

Solution Approach 1:

The sieve unit is designed with dynamic accessibility - it can be tilted or rotated into different positions during operation and maintenance. This dynamic positioning allows the sieve to maintain its grinding function in the working position while being easily accessible for removal and replacement when needed, eliminating the need to dismantle the entire mill structure for maintenance.

Inventive Principle:
Principle #15Dynamics

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 design reduces mill downtimes, simplifies maintenance, and optimizes product flow, leading to cost savings and improved process reliability by allowing for efficient setup and maintenance without dismantling major parts.

Implementation Method 1

An annular rotary bearing is provided on the feed tube to allow relative rotation between the feed tube and another component of the mill

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3247499B1Coaxial mill and feeding unit for a mill
Publication Date: 2018.09.12 ROBERT BOSCH GMBH
  • EP3247499B1 patent drawingFigure 1
  • EP3247499B1 patent drawingFigure 2
  • EP3247499B1 patent drawingFigure 3

AI summary

The invention relates to a mill (1) and to a feed unit (2) for a mill (1). The feed unit (2) comprises: a first interface (3) for holding a rotor (4) of a grinder (46), a second interface (5) for holding a stator (6) of the grinder (46), a feed pipe (7), which is arranged to feed material for grinding (8) into the grinder (46), and an annular rotary bearing (9) on the feed pipe (7) which is disposed in such a way that, in operation, material for grinding (8) enters the grinder (46) through the rotary bearing (9).