Coffee-making apparatus and method
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Solution Overview
Problem
Conventional espresso coffee machines and stove-top coffee-makers fail to achieve the ideal brew temperature and pressure for espresso coffee, resulting in sub-optimal brewing conditions that lead to under-extraction or over-extraction issues due to uneven water flow and pressure inconsistencies.
Innovation Solution
A coffee-making apparatus with a brew-water chamber and a boiling-water cooling chamber, where a pressure valve allows brew water to flow only when steam pressure exceeds 4 bar, enabling precise control of pressure and temperature decoupling, allowing brew water to be cooled to the desired temperature while maintaining pressure, ensuring ideal espresso brewing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a saturated boiler is used to generate brew pressure, then the system achieves simplicity and single heat source operation, but the brew temperature becomes excessive (above 100C) and cannot be controlled independently from pressure
Solution Approach 1:
The system is divided into two separate saturated boilers: a first saturated boiler for generating brew pressure and a second saturated boiler for providing cooled brew water. This segmentation allows independent control of pressure and temperature functions, resolving the contradiction between system simplicity and temperature control.
Solution Approach 2:
A heat exchanger is introduced as an intermediary between the two boilers. The heat exchanger transfers heat from the high-temperature brew water of the first boiler to the cooling water of the second boiler, enabling temperature reduction without direct thermal contact and maintaining pressure integrity.
2Use of energy by moving object
If a saturated boiler is used to generate both temperature and pressure, then the system operates with a single heat source, but the thermodynamic link prevents achieving both ideal temperature (90-96C) and ideal pressure (9 bar) simultaneously
Solution Approach 1:
The single heat source system is segmented into two functional units: a first saturated boiler dedicated to pressure generation and a second saturated boiler dedicated to temperature control. Both are heated by the same heat source, maintaining energy efficiency while achieving precise control over both pressure and temperature parameters.
Solution Approach 2:
The system changes the operating parameters of the two boilers differently: the first boiler operates at higher pressure and temperature to generate brew pressure, while the second boiler operates at atmospheric pressure with its cooling water temperature controlled to achieve the desired brew temperature (90-96C) through the heat exchanger.
3Device complexity
If ground coffee is held uncompressed in the chamber, then the system maintains simplicity, but brew water flows through too quickly causing under-extraction
Solution Approach 1:
The ground coffee is tamped (compressed) in advance before the brewing process begins. This preliminary compression increases the density and flow resistance of the coffee bed, ensuring that brew water flows at an appropriate rate during extraction, thereby improving extraction efficiency without adding complexity to the brewing mechanism.
4Stress or pressure
If ground coffee is tamped downwards towards the perforated base, then flow resistance increases, but high-pressure brew water creates cracks leading to uneven flow and under-extraction
Solution Approach 1:
The coffee is tamped to create initial compression and uniform density before brewing. This preliminary action ensures even flow distribution and prevents channeling during the high-pressure brewing phase.
Solution Approach 2:
A filter plate is introduced as an intermediary between the tamped coffee and the perforated base. The filter plate distributes the brew water flow evenly across the coffee surface and prevents direct high-pressure impact on the tamped coffee, eliminating crack formation while maintaining flow resistance for proper extraction.
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 apparatus consistently delivers brew water at the ideal temperature and pressure for espresso brewing, ensuring even extraction and producing a high-quality espresso beverage by decoupling temperature and pressure control, thus overcoming the limitations of existing technologies.
Implementation Method 1
a first saturated boiler adapted to generate a steam pressure sufficient to propel brew water through the heat exchanger and into the coffee chamber
Implementation Method 2
a heat exchanger arranged to cool the brew water to a desired temperature prior to the brew water being delivered into the coffee chamber
Implementation Method 3
a second saturated boiler adapted to heat cooling water to a controlled temperature... the temperature of the cooling water in the second saturated boiler substantially equilibrates with the desired temperature of the brew water
Implementation Method 4
a pressure valve openable when a steam pressure in the first saturated boiler exceeds a threshold pressure, to allow the brew water to pass through the heat exchanger
Data Source
Figure 1
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AI summary
A coffee-making apparatus has a brew-water chamber (2) and a boiling-water cooling chamber (8). A pressure valve (20), openable in use at a threshold pressure in the brew-water chamber, allows brew water to flow from the brew-water chamber through a conduit (16), in which the water is cooled by heat flow to boiling water in the boiling-water cooling chamber. A coffee-filter apparatus is additionally provided, comprising a container having a perforated outlet-wall, and a perforated filter plate positionable in the container to retain, in use, a source of coffee in the container. Coffee is made by directing the water from the conduit through the source of coffee and then through the perforated outlet-wall of the container into a coffee receptacle.