Preloaded Roller Pack for Stable Grinding Gap Adjustment

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Solution Overview

Problem

Roller packs in grinding devices face challenges in maintaining consistent grinding gap stiffness due to variable forces during regrind operations, leading to issues with starch damage, water absorption, and particle size distribution, especially when the mass flow fluctuates.

Innovation Solution

A roller pack design with a first and second bearing body that can be adjusted relative to each other, featuring a tensioning device and stop bodies with eccentric surfaces to maintain consistent prestressing force, allowing precise adjustment of the grinding gap width through rotational mechanisms and force sensors for precise force measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the bearing bodies are allowed to move relative to each other to adjust the grinding gap, then the grinding gap width is adjustable, but the stiffness of the grinding gap varies with force changes

Engineering Contradiction:

Improveadjustability of grinding gapVSAvoidstiffness of grinding gap

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The bearing bodies are pre-tensioned against each other by the clamping device before grinding operation begins. This preliminary action creates a stable force state that maintains consistent grinding gap stiffness during operation, preventing the stiffness variation problem that occurs when bearing bodies move freely during grinding.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The clamping device changes the force parameter between bearing bodies by applying a predetermined clamping force. This parameter change stabilizes the relative position of bearing bodies, thereby maintaining constant grinding gap stiffness while still allowing gap width adjustment through bearing body repositioning.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the rollers are pressed together with high force to maintain gap stiffness, then grinding performance improves, but the ability to deflect through foreign objects decreases

Engineering Contradiction:

Improvestiffness of grinding gapVSAvoidability to deflect through foreign objects

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The clamping device is designed with adjustable clamping force capability, allowing the system to dynamically change the force parameter between bearing bodies. This enables the grinding gap to be stiff during normal operation for good grinding performance, yet flexible enough to deflect when encountering foreign objects, as the clamping force can be reduced when needed.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If the bearing bodies are pre-tensioned to maintain consistent gap stiffness, then particle size distribution improves, but the device complexity increases

Engineering Contradiction:

Improveparticle size distributionVSAvoidcomplexity of bearing body adjustment mechanism

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The clamping device serves multiple functions: it pre-tensions the bearing bodies to maintain gap stiffness, allows adjustment of the grinding gap width, and provides a stable force state for consistent particle size distribution. By combining these functions into a single device, the overall system complexity is reduced despite the added pre-tensioning capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 ensures consistent grinding performance by maintaining the prestressing force between bearing bodies, allowing for precise control of the grinding gap width, thereby improving starch damage, water absorption, and particle size distribution, even with fluctuating mass flow rates.

Implementation Method 1

a display element (28) movable along the handwheel axis of rotation (H) relative to the position indicator housing (27) by means of at least one position indicator spring (29) pre-tensioned or can be pre-tensioned against the position indicator housing (27) in the direction of the handwheel axis of rotation (H)

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the stop surfaces are designed and arranged or can be arranged on the bearing bodies such that contact between the stop surfaces counteracts contact between the rollers

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP3597300B1Rolling packets for milling devices, milling devices and method

Publication Date: 2021.03.31 BUHLER AG

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AI summary

Disclosed are roller packages (10) for grinding devices (70), comprising a first roller (11) held by at least one first bearing body (13) and a second roller (12) held by at least one second bearing body (14). In a first aspect, it is provided that the first bearing body (13) and the second bearing body (14) are preloaded against each other and have stop bodies (17, 19) with stop surfaces (18, 20) whose contact opposes contact between the rollers (11, 12). The rotational position of the first stop body (17) determines the minimum width of the grinding gap. Also disclosed are grinding devices (70), methods for operating a roller package (10), and methods for determining the radial force acting between the rollers (11, 12) of a roller package (10).