Coffee Machine Brewing Flow Control for Smooth Cream Valve Opening
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Solution Overview
Problem
Conventional coffee machines experience abrupt dispensing of coffee beverages due to sudden opening of the cream valve, leading to spraying and potential scalding, while existing methods fail to ensure uniform wetting of coffee grounds and optimal flavor extraction.
Innovation Solution
A method involving a coffee machine with a brewing chamber and a cream valve pre-tensioned by a mechanical restoring device, where brewing water is supplied in varying volume flow rates to control the opening of the cream valve, ensuring gradual coffee dispensing and optimal wetting of coffee grounds, with distinct phases for pressure build-up and brewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the cream valve is opened suddenly by high water pressure, then coffee dispensing speed increases, but spraying and scalding occur
Solution Approach 1:
The brewing water pump is operated in a pulsed manner with alternating active and inactive phases. During the active phase, water is supplied to build pressure; during the inactive phase, pressure is maintained without additional supply. This periodic operation allows the cream valve to open gradually rather than suddenly, preventing spraying while maintaining adequate dispensing speed.
Solution Approach 2:
The method includes a pre-brewing phase where water is supplied at a reduced rate before the main brewing phase. This preliminary action allows the brewing chamber to pressurize gradually and the cream valve to open smoothly, avoiding sudden discharge and spraying while still achieving the required pressure for proper coffee extraction.
2Productivity
If brewing water is supplied continuously at high flow rate, then brewing speed increases, but uniform wetting of coffee grounds is insufficient
Solution Approach 1:
The brewing water pump operates in pulses rather than continuously. During active phases, water is supplied to advance the brewing process; during inactive phases, the water flow stops momentarily. This periodic action disrupts the formation of preferential flow paths and ensures more uniform distribution of water throughout the coffee grounds, improving wetting uniformity while maintaining overall brewing speed.
Solution Approach 2:
The brewing process dynamically adjusts the water supply rate by alternating between high flow rates during active phases and zero flow during inactive phases. This dynamic operation allows water to penetrate different regions of the coffee grounds at different times, ensuring more uniform saturation compared to continuous high-flow operation which creates channeling effects.
3Stability of the object's composition
If the brewing water pump is operated intermittently, then wetting uniformity improves, but the volume flow rate is reduced to zero during interruptions
Solution Approach 1:
The brewing water pump is operated in a periodic manner with defined active and inactive phases. During active phases, the pump delivers water at normal flow rates to advance brewing; during inactive phases, the pump stops temporarily. This periodic operation maintains adequate overall water quantity while improving distribution uniformity by preventing continuous channel formation.
Solution Approach 2:
Although the pump operates intermittently, the brewing process maintains continuity through pressure maintenance during inactive phases. The pressure built up during active phases sustains the brewing process during pump interruptions, ensuring that the temporary reduction in flow rate does not significantly impact overall productivity while still achieving uniform wetting.
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 abrupt coffee dispensing, ensures uniform release of brewed coffee, maintains consistent brewing temperature, and enhances flavor extraction by gradual wetting of coffee grounds, reducing the risk of splashing and improving overall coffee quality.
Implementation Method 1
a cream valve (38) which is pre-tensioned in a closure direction (39-1) by means of an independent mechanical restoring device (39)
Implementation Method 2
the brewing water running through the brewing chamber wets the ground coffee contained in the brewing chamber
Data Source
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.