Filter coffee machine
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Solution Overview
Problem
Filter coffee machines with separate heating elements for different heat outputs are costly to manufacture and consume quiescent current when in standby mode.
Innovation Solution
A filter coffee machine with a main switch and an electrically controllable switching element, such as a thyristor, allows independent control of the heating unit's power supply, enabling cost-effective heat output control and eliminating quiescent current consumption by using a control unit to manage the switching element and power pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate heating elements are used for different heat outputs, then multiple heating levels are achieved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple heating functions into a single heating element by using a phase-controlled switching device (triac) that can vary the power delivery to one heating element. This eliminates the need for multiple separate heating elements while still providing multiple heating levels (e.g., 500W, 600W, 1100W) through electronic control of the single element's power consumption.
Solution Approach 2:
The patent changes the operational parameters of a single heating element by controlling the phase angle at which the triac switches on during each AC cycle. By varying the firing angle, the effective power delivered to the heating element is adjusted, enabling multiple heating levels without requiring multiple physical heating elements with different power ratings.
2Ease of operation
If the main switch directly disconnects the main circuit from power supply lines, then switching is simple, but high electrical power and currents are required
Solution Approach 1:
The patent introduces a triac as an intermediary switching device between the main switch and the heating element. The main switch only needs to control the low-power gate terminal of the triac, while the triac's main terminals handle the high-power connection to the heating element. This mediator approach allows the main switch mechanism to be designed for significantly lower electrical power and currents.
Solution Approach 2:
The patent replaces the direct mechanical/electrical switching of high currents with an electronic control approach. Instead of using a mechanically robust switch rated for high currents, a simple low-power switch controls the gate of a triac, which electronically manages the high-current path to the heating element.
3Speed
If the coffee machine remains in stand-by mode, then quick readiness is achieved, but quiescent current consumption occurs
Solution Approach 1:
The patent uses the periodic nature of AC power cycles in combination with the triac's latching characteristic. The triac remains conductive throughout the entire AC cycle once triggered, allowing the heating element to receive continuous power without requiring the control circuit to remain actively switched on. This periodic operation with latching behavior eliminates quiescent current consumption while maintaining heating readiness.
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 allows for efficient, cost-effective control of heating output and eliminates standby power consumption by using a thyristor to manage the heating unit's power supply, enabling multiple heating levels and preventing quiescent current draw.
Implementation Method 1
Anode and cathode of the thyristor are connected in an AC line to a pole of the supply network. A control signal for the thyristor can thus be fed independently of the control unit, in particular using the main switch, so that the main circuit can be connected to the supply network independently of the control unit.
Implementation Method 2
heating a defined amount of preparation water for coffee by the heating unit
Data Source
Figure 1
Figure 2~3
AI summary
The filter coffee machine (1) comprises a main switch (500) for turning on the coffee machine, and a main circuit (I) having a heating unit (300) and an electrically controllable switching element (100). The main circuit is connectable to a power supply terminal (10) of the coffee machine, through the electrically controllable switching elements. The coffee machine comprises a control unit (200) that generates a signal (IG) for the control of the electrically controllable switching elements. An independent claim is included for a control method of filter coffee machine.