Coffee Machine Pump Control for Quiet Variable-Flow Extraction
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Solution Overview
Problem
Existing coffee machines struggle to maintain high coffee quality across different cup sizes due to inconsistent water flow rates, leading to over- or under-extraction, and are often noisy due to PID controller variations and mechanical operation.
Innovation Solution
A coffee machine with a control unit that converts DC power into amplitude-variable electrical pulse signals to drive hydraulic pumps, allowing for variable flow rates and silent operation, featuring two pumps driven 180° out of phase for smooth and quiet brewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PID controller is used to regulate water flow rate, then flow control precision is improved, but noise level increases due to mechanical operation and controller variations
Solution Approach 1:
The patent replaces the mechanical PID controller with an electronic pulse width modulation (PWM) control system. The control unit generates amplitude-variable electrical pulse signals that drive the hydraulic pump motor, eliminating mechanical linkages and reducing noise while maintaining precise flow rate regulation through electronic feedback from the flow meter.
Solution Approach 2:
The patent employs periodic pulse signals with variable amplitude (PWM) to control the hydraulic pump motor. By adjusting the duty cycle of these periodic pulses, the system achieves precise control over the motor speed and consequently the water flow rate, while the periodic nature allows for smooth operation at reduced noise levels.
2Stability of the object's composition
If a constant flow rate is maintained, then extraction consistency is improved, but adaptability to different cup sizes deteriorates
Solution Approach 1:
The patent implements a dynamic control system where the water flow rate is continuously adjusted based on real-time feedback from the flow meter and control unit. The system can adapt the flow rate dynamically during the brewing process and across different brewing scenarios, maintaining optimal extraction while accommodating various cup sizes and coffee types.
Solution Approach 2:
The patent incorporates a flow meter that continuously measures the actual water flow rate and feeds this information back to the control unit. The control unit processes this feedback and adjusts the PWM signal amplitude accordingly, ensuring the flow rate remains within the optimal range for extraction while allowing flexibility for different cup sizes and brewing requirements.
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 solution ensures consistent coffee extraction time and quality across varying cup sizes while minimizing noise and electromagnetic interference, achieving silent and efficient operation with improved flow control and reduced environmental disturbance.
Implementation Method 1
a control tool (11) driving a converter (12) converting DC power (14) at a powerline into an amplitude variable electrical pulse signal (17) at a driver line (17) that drives the at least one hydraulic pump (2, 3)
Data Source
AI summary
A coffee machine for producing and dispensing coffee-based beverages comprising: at least one hydraulic pump, a boiler and a brewer unit equipped to receive ground coffee and pass through hot water received from the boiler, and comprising a flow meter to measure the flow of water and a control unit receiving electrical signals from the flow meter and controlling the at least one hydraulic pump to regulate the flow rate of water, wherein the coffee machine incorporates an input of the control unit that establishes a variable set-point value of the flow rate that depends on a desired fixed extraction time of the ground coffee received in the brewer unit, wherein the control unit is arranged to calculate a difference between the variable setpoint value of the flow rate, and a measured value from the flow meter, and that the control unit supplies this difference as an error value to a control tool, and wherein the control tool drives a converter that converts DC power at a powerline into an amplitude variable electrical pulse signal at a driver line that drives the at least one hydraulic pump.