Coffee Machine Flow Control for Gradual Crema Valve Opening

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Solution Overview

Problem

Conventional coffee brewing methods result in sudden and high-pressure dispensing of coffee, leading to potential spills and scalding, due to unpredictable crema valve opening, which compromises crema quality and flavor distribution.

Innovation Solution

A method involving controlled volume flow variations during brewing, with distinct phases of water supply to the brewing chamber, ensuring gradual crema valve opening and consistent brewing pressure, utilizing a crema valve with a mechanical restoring device to manage the outlet flow, and employing a pump control device for precise flow regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If brewing water is supplied at high flow rate to build pressure quickly, then brewing time is reduced, but crema valve opens suddenly causing high-pressure dispensing and potential spills

Engineering Contradiction:
Improvebrewing timeVSAvoidsudden high-pressure dispensing
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The brewing water supply is divided into multiple phases with different flow rates. A first volume flow supplies water during a first time period to build initial pressure, followed by a second volume flow during a second time period to maintain pressure. This periodic variation in flow rate prevents sudden pressure spikes that would cause the crema valve to open abruptly, while still achieving complete coffee extraction within a reasonable time.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the brewing water flow rate based on the brewing phase. The pump control device varies the volume flow from a first flow rate during the initial phase to a second flow rate during the subsequent phase. This dynamic control allows the system to build pressure gradually and maintain it steadily, preventing sudden crema valve opening while optimizing brewing efficiency.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If brewing water supply is interrupted in pulsed manner to wet ground coffee completely, then wetting homogeneity is improved, but volume flow is reduced to zero during interruptions

Engineering Contradiction:
Improvewetting homogeneityVSAvoidvolume flow
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The brewing process uses periodic water supply phases to achieve complete wetting of ground coffee. The first time period supplies water to initiate wetting, and the second time period continues water supply to ensure complete permeation. This periodic action ensures homogeneous wetting while maintaining continuous water flow, avoiding the productivity loss associated with complete flow interruptions.

Inventive Principle:
Principle #19Periodic action

3Stress or pressure

If crema valve opens suddenly due to pressure buildup, then brewing pressure is high for efficient extraction, but coffee shoots out at high speed causing spills and scalding

Engineering Contradiction:
Improvebrewing pressureVSAvoidcoffee shooting out at high speed
Core Design Contradiction:
Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The pump control device dynamically adjusts the water supply flow rate to match the brewing phase requirements. During the first time period, a higher first volume flow builds necessary pressure for extraction. During the second time period, the flow rate is adjusted to a second volume flow that maintains pressure while preventing sudden spikes. This dynamic control ensures the crema valve opens gradually, allowing coffee to dispense at a controlled speed without shooting out and causing hazards.

Inventive Principle:
Principle #15Dynamics

4Productivity

If pump operates at nominal power throughout brewing cycle, then productivity is maximized, but brewing temperature may fluctuate and crema quality may be inconsistent

Engineering Contradiction:
Improvebrewing efficiencyVSAvoidcrema quality consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The pump control device implements periodic operation with distinct phases. During the first time period, the pump operates at a power level appropriate for initial water supply and pressure buildup. During the second time period, the pump operates at a different power level to maintain steady pressure and temperature for consistent crema formation. This periodic power adjustment ensures both brewing efficiency and reliable crema quality.

Inventive Principle:
Principle #19Periodic action

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 approach prevents sudden coffee dispensing, ensures consistent crema quality, and allows for optimal flavor extraction and aroma release, while maintaining a constant brewing temperature, thereby improving the overall coffee brewing process.

Implementation Method 1

at least part of the brewing water supply is used for the initial pressure build-up in the brewing chamber

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

a spring-loaded crema valve being switched on in the coffee outlet line and opening automatically when pressure is applied

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

If the water pressure inside the brewing chamber increases during a brewing process due to the brewing water supplied, such a known crema valve is pressed into its open position by the increasing pressure against the restoring force of the spiral spring

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 4

the brewing water thus passing through the brewing chamber wets the ground coffee received in the brewing chamber, so that brewed coffee beverage can be dispensed at the chamber outlet

Methodology Applied
Scientific EffectExtraction:

Data Source

PatentEP2755533B1Method for producing a coffee beverage and coffee machine for performing the method
Publication Date: 2015.11.18 JURA ELEKTROAPPARATE AG
  • EP2755533B1 patent drawingFigure 1
  • EP2755533B1 patent drawingFigure 2
  • EP2755533B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for producing a coffee beverage in a brewing chamber (36) of a coffee machine (10) and to a coffee machine (10) for performing a method for producing a coffee beverage. The aim of the invention is to improve the dispensing of coffee, especially in its first phase, in order to avoid undesired splashing due to increased pressure of the coffee beverage at the coffee beverage outlet (47), According to the method of the invention, the brewing water is supplied to the brewing water inlet (35-1) of the brewing chamber (36) at a first volume flow rate during a first period of time (T1) of a first brewing phase (a), and during a second period of time (T2) of the first brewing phase (a), the brewing water is supplied to the brewing water inlet (35-1) of the brewing chamber (36) at a second volume flow rate, wherein the first volume flow rate and the second volume flow rate are both different from zero and wherein the second volume flow rate is lower than the first volume flow rate.