Coffee Roasting Agitator Blade Set: Minimum Air Gap for Contact-Free Agitation

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Solution Overview

Problem

Existing food roasting machines face challenges in precision manufacturing and mechanical failure due to mechanical contact between agitation blade sets and roasting chambers, exacerbated by thermal cycling, leading to noise and jamming issues.

Innovation Solution

A roasting drum with a curved inner surface and an agitator blade set having a minimum gap between the blade ends and the curved lower wall, combined with opposing rotational directions of air flow and blade rotation, to prevent bean accumulation and enhance agitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the agitation blade set is positioned close to the roasting chamber wall to improve agitation efficiency, then bean agitation is enhanced, but mechanical contact occurs causing noise and mechanical failure

Engineering Contradiction:

Improveagitation efficiencyVSAvoidmechanical failure

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces direct mechanical contact between the agitation blade set and roasting chamber wall with a pneumatic system. High-velocity air jets are directed along the curved lower surface to create a fluid dynamic barrier that prevents bean accumulation, eliminating the need for the agitation blades to physically contact the chamber wall while maintaining effective agitation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses high-velocity air jets delivered through nozzles positioned near the curved lower surface of the roasting chamber. The pneumatic flow creates a virtual barrier that prevents bean accumulation and facilitates agitation without requiring mechanical contact between moving parts and the chamber wall, thus improving reliability while maintaining productivity.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Reliability

If precision manufacturing is improved to reduce mechanical contact, then mechanical failure is reduced, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvemechanical failureVSAvoidmanufacturing precision

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for high-precision manufacturing of the roasting chamber wall and agitation blade set by replacing mechanical contact with a pneumatic system. The air jet system tolerates variations in manufacturing precision while still effectively preventing bean accumulation and avoiding mechanical contact, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Duration of action of stationary object

If thermal cycling resistance is improved to prevent mechanical contact damage, then agitator blade life is extended, but system complexity increases

Engineering Contradiction:

Improveagitator blade lifeVSAvoidsystem complexity

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent extends agitator blade life by replacing mechanical contact with pneumatic agitation. The air jet system prevents beans from accumulating on the curved lower surface, eliminating repeated mechanical impact and thermal cycling stress on the blades. This approach extends blade life without adding significant system complexity, as the pneumatic system integrates seamlessly with the existing roasting chamber.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution improves agitation efficiency, extends agitator blade life, and reduces mechanical failures by minimizing mechanical contact and thermal stress, ensuring consistent roasting quality.

Implementation Method 1

an air inlet chamber fluidically coupled to the roasting chamber and configured to direct air toward the curved inner surface which redirects the air in a first rotational direction

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

The opposing directions of the air flow and the blade rotation has the surprising result of improving agitation of the beans

Methodology Applied

Scientific EffectCounter-rotation agitation:

Data Source

PatentUS20250241351A1Coffee roasting system having an agitator blade set with a minimum air gap

Publication Date: 2025.07.31 BELLWETHER COFFEE CO

AI summary

A bean roasting system comprises a roasting drum including (1) a housing enclosing a roasting chamber and having a curved inner surface defined by a curved lower wall, and (2) an air inlet chamber fluidically coupled to the roasting chamber and configured to direct air toward the curved inner surface which redirects the air in a first rotational direction. A distal end of each blade from a plurality of blades is disposed from a axis of rotation toward the curved lower wall by a distance no greater than R. The curved lower wall is spaced at least a distance R+G from the axis of rotation to provide a minimum gap G. The agitator blade set and the directed air are collectively prevents accumulation of beans along the curved lower surface during a roasting process.