Capacitive Flow Detection Circuit for Beverage Dispensing Ducts
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Solution Overview
Problem
Existing flow detection systems for beverage dispensing systems are inefficient due to the use of bulky and expensive inductances, requiring significant circuitry for frequency-to-voltage conversion, and lack simplicity in signal processing.
Innovation Solution
A flow detection circuit utilizing a capacitive sensor with alternating signal sources, capacitive elements, and processing circuits to detect signal amplitude, allowing implementation in the analogue or digital domain, and incorporating a feedback control loop for precise signal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inductance is used for frequency variation in capacitive flow measurement, then measurement capability is achieved, but device size increases and cost increases
Solution Approach 1:
The patent replaces the mechanical/physical inductance component with an electronic implementation using capacitive elements and signal processing circuits. The flow detection function is achieved through capacitive coupling and amplitude detection rather than inductive frequency modulation, eliminating the need for bulky inductance components while maintaining measurement capability.
Solution Approach 2:
The patent changes the detection parameter from frequency variation (which requires inductance) to amplitude variation of the capacitive signal. By detecting amplitude changes in the capacitive element rather than frequency changes, the system eliminates the need for inductance-based frequency modulation circuits, reducing size and cost.
2Measurement precision
If inductance is used for frequency variation, then flow measurement is enabled, but manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive inductance components with simpler capacitive elements and standard signal processing circuits. Capacitors are generally smaller, cheaper, and easier to manufacture than inductors, especially in integrated circuit form. The amplitude detection circuitry required is more straightforward and cost-effective than frequency-to-voltage conversion circuits.
Solution Approach 2:
The patent employs inexpensive capacitive elements and standard electronic components that can be easily manufactured and replaced if needed, rather than expensive inductance-based systems. The simplified circuit architecture uses common, low-cost components that reduce overall manufacturing expenses.
3Measurement precision
If frequency-to-voltage conversion circuitry is used, then signal processing is achieved, but device complexity increases
Solution Approach 1:
The patent changes the detection approach from frequency-domain analysis to amplitude-domain detection. By measuring the amplitude of the capacitive signal directly rather than converting frequency variations to voltage, the system eliminates complex frequency-to-voltage conversion circuits and associated signal processing stages, significantly reducing overall circuit complexity.
Solution Approach 2:
The patent extracts and removes the complex frequency-to-voltage conversion circuitry from the system by adopting an alternative amplitude-based detection method. This extraction eliminates unnecessary intermediate processing stages, simplifying the overall circuit architecture while maintaining the essential flow detection function.
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 system reduces complexity and cost by using capacitive sensors, enabling efficient flow detection with reduced circuitry, and provides real-time feedback on flow characteristics and container type, allowing for precise control and user feedback.
Implementation Method 1
a capacitive element (204) comprising two electrodes (132, 134) provided at opposite sides of the duct (120)
Data Source
AI summary
A dispensing system for a beverage comprises in a tap system a bore for housing a duct. Along the bore, close to or on the duct, at least two electrodes are provided such that at least at some locations along the duct, the two electrodes are provided opposite to one another with the duct in between, thus constituting a capacitor. An oscillating signal is provided to one electrode and a signal is read out from the other electrode. As a beverage is drawn through the duct in a container, capacitance of the capacitor changes. The flowing beverage may have different characteristics, but capacitance may also change as the beverage in the duct is in conducting contact with a container that may be in contact with an earth contact. The change of capacitance results in a change of the amplitude of a detection circuit connected to the second electrode.