Electric coffee grinder
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Solution Overview
Problem
Current electric coffee grinders face issues such as overheating of coffee beans due to high motor speeds, inconsistent granulometry, and wear-related variations in powder quality, leading to suboptimal organoleptic characteristics and inefficient burr replacement schedules.
Innovation Solution
A coffee grinder utilizing a synchronous brushless motor with a high number of poles for low-speed, high-torque operation, directly connected to the grinding mechanism without speed reducers, and equipped with a control unit and encoder for precise speed control and wear monitoring, allowing for customizable speed profiles and real-time adjustment based on environmental and operational parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high-speed electric motor is used to drive the rotating burr, then the grinding efficiency is improved, but the coffee powder overheats and organoleptic characteristics are degraded
Solution Approach 1:
The patent changes the rotational speed parameter from high (1400-3000 rpm) to low (below 750 rpm) by using a high-pole-count motor (12-24 poles), thereby preventing overheating while maintaining adequate grinding efficiency through the high-torque capability of the motor at low speeds
2Temperature
If a speed reducer is used to reduce motor rotation speed below 750 rpm, then overheating is avoided, but the device becomes bulkier, more expensive, and noisier
Solution Approach 1:
The patent replaces the mechanical speed reduction system (gearbox, belt drive) with an electrical solution - a high-pole-count motor that inherently operates at low speeds. The motor's electromagnetic design (12-24 poles) directly produces low-speed high-torque output, eliminating the need for mechanical speed reducers and their associated bulk, cost, and noise
3Speed
If an induction motor is used to drive the burrs, then the motor can operate at lower speeds, but the speed is not constant and precise quantity control is difficult
Solution Approach 1:
The patent incorporates a feedback control system with an encoder that monitors the motor's rotational position and speed, providing real-time feedback to the control unit. This enables precise control of the burr rotation speed and accurate counting of revolutions, allowing precise quantity control of ground coffee despite the motor being asynchronous
4Productivity
If the burrs are used for extended periods without replacement, then productivity is maintained, but wear causes granulometry variation and quality degradation
Solution Approach 1:
The patent uses feedback from the encoder to monitor the actual number of burr revolutions and operating time, providing data to the control unit that tracks burr wear. This enables intelligent determination of replacement timing based on actual usage patterns and wear indicators, optimizing the balance between productivity and quality
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 solution enables coffee grinding at low speeds without overheating, maintaining consistent granulometry, and allowing for precise control of coffee quantity and quality, reducing noise and wear-related issues, while optimizing burr replacement timing and ensuring high-quality coffee powder production.
Implementation Method 1
A coffee grinder utilizing a synchronous brushless motor with a high number of poles for low-speed, high-torque operation
Data Source
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AI summary
Electric coffee grinder characterized by comprising: - a container (2) for containing the coffee beans to be ground, - a grinding mechanism (4) comprising at least a pair of burrs (6,8) configured to receive and grind the coffee beans to be ground contained in said container (2), a burr (6) being fixed with respect to said container (2) and the other burr (8) being directly coupled, without the interposition of reducers and/or gears, to the output shaft (10) of a torque motor (12) which is controlled by a control unit (18), said torque motor (12) being configured so as to be able to rotate at an adjustable speed between about 0 and 1200 rpm and so as to develop a substantially constant torque not exceeding 20 Nm.