Apparatus for preparing a coffee beverage
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Solution Overview
Problem
Current coffee brewing apparatuses lack precision in controlling the pressure exerted by plungers on coffee powder, leading to fluctuations in flavor quality due to accidental pressure variations caused by frictional forces and temperature influences, resulting in either under-extraction or over-extraction of bitter substances.
Innovation Solution
An apparatus with a rotary encoder-controlled electric actuator that moves the plunger with calibrated precision, independent of frictional forces and temperature, allowing for reproducible pressure adjustment on the coffee powder during brewing by using a gear mechanism and electronic control device to manage the plunger's movement based on encoded pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple electric motor is used to move the plunger without rotational angular position detection, then the device complexity is reduced, but the manufacturing precision of plunger positioning deteriorates
Solution Approach 1:
A rotary encoder detects the rotational angular position of the motor shaft and provides feedback signals to the control device. The control device uses this feedback to precisely control the plunger's position and movement, achieving accurate positioning while maintaining a relatively simple device structure.
Solution Approach 2:
The patent replaces pure mechanical positioning mechanisms with an electromechanical system combining a simple electric motor and a rotary encoder. This substitution allows for precise digital control of plunger position without complex mechanical linkages or manual adjustment mechanisms.
2Ease of operation
If the plunger travel path is determined by coffee powder amount and gear friction, then the ease of operation is improved, but the manufacturing precision of pressure application deteriorates
Solution Approach 1:
The rotary encoder provides real-time feedback on the plunger's position, allowing the control device to compensate for variations in coffee powder amount and gear friction. The system automatically adjusts the motor's rotational angular position to ensure the plunger reaches the precise brewing position regardless of these variables.
Solution Approach 2:
The system performs a calibration process before brewing to establish the relationship between motor rotational angular position and plunger position. This preliminary action stores reference data that enables precise pressure application during subsequent brewing operations, compensating for variations in coffee powder characteristics.
3Productivity
If the electric motor is activated for a set period without position detection, then the productivity is improved, but the manufacturing precision of brewing pressure deteriorates
Solution Approach 1:
The rotary encoder continuously monitors the motor's rotational angular position during the brewing process, providing real-time feedback to the control device. This allows the system to maintain precise control over plunger position and brewing pressure while operating at high speed, eliminating the need for slow, incremental positioning.
Solution Approach 2:
The system uses periodic pulse signals from the rotary encoder to track and control the motor's rotational position. This periodic feedback mechanism enables rapid, precise control of the plunger's movement and pressure application, achieving both high productivity and precise brewing pressure.
Data Source
AI summary
A coffee brewer contains a brewing unit in which coffee grounds having been poured in are compressed by a plunger driven by an actuator. Heated water flows through the compressed coffee grounds. A control device controls the actuator in accordance with signals of an angle of rotation sensor. The control device first moves the plunger against a stop in an ejection position to calibrate the sensor, then moves the plunger by a predetermined distance in a downwards direction into a pouring-in position. Afterwards the control device moves the plunger by a second distance into the brewing position, a length of the predetermined distance and the second distance corresponds to a number of pulses of the sensor which are stored in the memory. The control device subsequently moves the plunger by a third distance back into the ejection position in which the coffee grounds are removed from the plunger.