Coffee Grinder Feedback Control for Consistent Particle Size
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Solution Overview
Problem
Existing espresso and fully automatic coffee machines lack the ability to determine and adjust the particle size distribution of ground coffee accurately, leading to inconsistent brewing times and coffee quality due to reliance on visual assessment and non-adjustable grinding disc spacing.
Innovation Solution
The coffee machine incorporates a system for determining the density of ground coffee through dry and wet pressing, using sensors to calculate the particle size distribution and adjust the grinding disc distance for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the grinding disc spacing is adjusted to control particle size distribution, then the degree of grinding can be modified, but the particle size distribution remains inconsistent due to non-adjustable variables such as plane parallelism and fine tooth depth
Solution Approach 1:
The patent implements an automatic feedback system that measures the actual particle size distribution of ground coffee and uses this information to adjust the grinding disc spacing. The system includes a measurement device that determines the x63.2 value (particle size at which 63.2% of particles are smaller) and a control unit that automatically adjusts the grinding mechanism to achieve the desired particle size distribution, eliminating the need for manual trial-and-error adjustment and ensuring consistent results despite variations in disc parallelism or tooth depth.
2Device complexity
If visual assessment or brewing time is used to determine particle size distribution, then no complex measurement devices are needed, but the determination is only approximate and indirect
Solution Approach 1:
The patent replaces indirect mechanical assessment methods (visual inspection of ground coffee or measurement of brewing time) with direct optical or electromagnetic measurement systems. The measurement device uses light scattering, absorption, or other optical properties to directly determine the particle size distribution and x63.2 value of ground coffee, providing precise and objective measurements without requiring complex mechanical sieving or time-consuming brewing tests.
3Ease of operation
If the grinding degree is set manually by customer service technicians based on feeling, then the system remains simple to operate, but the setting is not reproducible and requires re-adjustment when bean type changes or discs wear
Solution Approach 1:
The patent implements a self-service system where the coffee machine automatically measures its own ground coffee particle size distribution and adjusts its own grinding disc spacing without external intervention. The system includes automatic measurement of the x63.2 value and automated adjustment of the grinding mechanism, allowing the machine to self-optimize for different bean types and compensate for disc wear over time, eliminating the need for manual re-adjustment by technicians.
4Length of moving object
If the distance between grinding discs is increased to coarsen the grind, then the particle size increases, but the correlation between disc spacing and actual particle size distribution is limited and non-reproducible
Solution Approach 1:
The patent transforms the static, fixed relationship between disc spacing and particle size into a dynamic, adaptive system. The grinding disc spacing is no longer a fixed setting but becomes a variable that is continuously adjusted based on real-time measurement feedback. The system dynamically modifies the disc spacing to compensate for variations in bean type, moisture content, and disc wear, ensuring that the desired particle size distribution is achieved regardless of initial spacing conditions.
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 method allows for automatic and reproducible determination and adjustment of the particle size distribution, ensuring consistent coffee quality and brewing time, even with changes in coffee beans or grinding disc wear.
Implementation Method 1
a sensor which is designed to determine a position or a travel path of the pressing element during or after such pressing of the defined amount of coffee powder
Implementation Method 2
compressing the defined amount of coffee powder in the brewing chamber with the brewing piston
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The present invention relates to an espresso machine or a fully automatic coffee machine having a grinder (1) and an infusion device comprising an infuser (2) and an infusion chamber (3), which is characterized by a volume-determining section (4) designed to determine the ground volume (V) of a defined quantity (K) of coffee powder ground by means of the grinder, a mass-determining section (5) designed to determine the ground mass (m) of said quantity (K) of coffee powder, and a calculating section (6), with which, on the basis of a predefined relationship (Z), preferably stored in the calculating section itself, between the grain size distribution and/or the degree of grinding of ground coffee, on the one hand, and the mass and the volume or a variable derived from these two variables, in particular the density, of ground coffee, on the other hand, it is possible to calculate the grain size distribution and/or the degree of grinding of said quantity (K) of coffee powder from the determined ground volume (V) and the determined ground mass (m).