Decoction device and extraction apparatus

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Solution Overview

Problem

Existing decoction devices for espresso preparation face issues with high torsion and load on the piston rod due to simultaneous translation and rotation movements, limiting design freedom and requiring heavy construction or separate motors, which affects powder distribution and coffee quality.

Innovation Solution

The second chamber bottom is made rotatable within the chamber wall, allowing independent control of rotation relative to the chamber wall during the approach movement, decoupling the axial translation of the first chamber bottom, and using a gearwheel transmission and slip coupling to optimize powder distribution with a single motor drive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the piston rod performs simultaneous translation and rotation movements to compress and distribute coffee powder, then powder distribution homogeneity is improved, but the torsion and load on the piston rod increase significantly

Engineering Contradiction:
Improvepowder distribution homogeneityVSAvoidtorsion and load on piston rod
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The patent divides the compression and rotation functions into separate components: the piston rod performs only axial translation for compression, while a separate rotatable chamber bottom performs rotation. This segmentation eliminates the need for the piston rod to withstand high torsional loads while maintaining powder distribution homogeneity through the rotating chamber bottom.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of rotating the piston rod during compression as in prior art, the patent inverts the approach by making the chamber bottom rotatable while the piston rod remains stationary in terms of rotation. This reversal transfers the rotation function from the compression element to the containment element, reducing load on the piston rod.

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

2Reliability

If the piston rod is made heavier to withstand high torsion during simultaneous translation and rotation, then structural reliability is improved, but device complexity and material usage increase

Engineering Contradiction:
Improvestructural reliability of piston rodVSAvoidpiston rod construction
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent separates the structural load-bearing function (piston rod for compression) from the rotation function (chamber bottom). This allows the piston rod to be optimized for compression only, using lighter materials and simpler construction, while the rotation is handled by a separately driven rotatable chamber bottom.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By making the chamber bottom rotatable instead of the piston rod, the patent eliminates the need for a heavily constructed piston rod capable of withstanding torsion. The inversion of which component performs rotation simplifies the piston rod design while maintaining structural reliability through the separate rotation mechanism.

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

3Adaptability or versatility

If separate motors are used to control translation and rotation movements independently, then movement control freedom is improved, but device complexity and component count increase

Engineering Contradiction:
Improvemovement control freedomVSAvoidnumber of motors
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the rotation drive with the linear actuator system by making the chamber bottom rotatable within the same actuation mechanism. This merging allows both translation and rotation to be controlled through a single actuator system, reducing component count while maintaining independent control capability through the rotatable chamber bottom design.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If a single motor drive is used to control both translation and rotation movements, then device complexity is reduced, but movement control precision and independence deteriorate

Engineering Contradiction:
Improvenumber of motorsVSAvoidmovement control precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the movement control by making the chamber bottom rotatable within the actuator system, allowing the single motor to independently control translation through the screw mechanism while rotation is achieved through the rotatable chamber bottom interface, maintaining precision for both movements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rotatable chamber bottom provides dynamic control capability, allowing the system to adjust rotation independently during the compression stroke. This dynamic feature enables precise control of both translation and rotation movements even with a single motor drive, maintaining manufacturing precision while reducing device complexity.

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 solution reduces the load on the actuator, allows for independent control of movements, enhances powder distribution, and improves coffee quality and uniformity while saving materials and components by using a single motor for both movements, with a slip coupling providing a safety mechanism against overload.

Implementation Method 1

at least the first chamber bottom is coupled to a linear actuator and is axially movable in the decoction chamber so as to compress the powder in the decoction chamber to a bed

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a drive is provided to impose a relative rotation between at least one of the chamber bottoms and the chamber wall as the chamber bottoms approach each other

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The coffee powder is hereby entrained and is thus better distributed over the surface of the chamber bottom

Methodology Applied
Scientific EffectEntrainment: Entrainment

Data Source

PatentEP3473146B1Decoction device and extraction apparatus
Publication Date: 2021.04.07 J M DE JONG DUKE AUTOMATENFABRIEK BV
  • EP3473146B1 patent drawingFigure 1~2
  • EP3473146B1 patent drawingFigure 3

AI summary

A decoction device for an extraction apparatus, in particular for preparing espresso, comprises a decoction chamber (7) enclosed by a chamber wall (5) for receiving a quantity of powder therein. The decoction chamber is situated between a first chamber bottom (20) and a second chamber bottom (30). The first chamber bottom (20) is coupled to a linear actuator and is axially movable in the decoction chamber so as to compress the powder to a bed. A drive is provided to impose a relative rotation between one of the chamber bottoms and the chamber wall as the chamber bottoms (20,30) approach each other. The respective chamber bottom (30) is for this purpose rotatable within the chamber wall (5) and the drive is able and configured to impose a rotation thereon during an approach movement of the first chamber bottom (20). A slip coupling (60) is provided in the transmission.