Fluid Control System Using Reservoir Pressure for Gas Displacement
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Solution Overview
Problem
Existing air pumps, particularly highly controllable acoustic resonance pumps, do not provide a fixed positive displacement of fluid, making them unsuitable for applications requiring precise fluid volumes or controlled flow rates, and alternative technologies like syringe pumps or systems with inline flow sensors are costly and complex.
Innovation Solution
A fluid control system that includes a reservoir with a pressure sensor, a piezoelectric acoustic resonance pump, and a controller to manage gas displacement based on pressure changes and storage volume, allowing for precise control of gas flow without the need for inline sensors, using a configurable storage volume and leak-back connections to maintain pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If syringe pumps or systems with inline flow sensors are used to provide fixed positive displacement, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the need for complex inline flow sensors and syringe pump mechanisms by extracting the measurement function to a pressure sensor located in a reservoir. The system measures pressure changes in the reservoir to determine flow rates, eliminating the need for direct flow measurement in the fluid path and simplifying the overall system architecture while maintaining precision.
Solution Approach 2:
The patent introduces a reservoir as an intermediary component between the pump and the fluid delivery system. This reservoir acts as a buffer that allows indirect measurement of flow through pressure sensing, rather than direct measurement. The intermediary reservoir decouples the measurement function from the flow path, reducing complexity while preserving measurement accuracy.
2Measurement precision
If inline flow sensors are used to measure flow rate, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the flow measurement function from the fluid path by using a pressure sensor in the reservoir instead of an inline flow sensor. The measurement is performed indirectly through pressure changes, removing the need for complex flow sensors in the fluid path while maintaining measurement precision.
Solution Approach 2:
The patent replaces mechanical flow sensors with a pressure-based measurement system. Instead of using mechanical elements to directly measure flow, the system uses pressure sensing and calculation based on pressure changes over time to determine flow rate, simplifying the measurement mechanism.
3Device complexity
If differential measurement over an orifice is used to measure flow rate, then device complexity is reduced, but measurement precision deteriorates due to vulnerability to flow character changes
Solution Approach 1:
The patent implements a feedback mechanism where the pressure sensor continuously monitors reservoir pressure, and the controller adjusts pump operation based on the measured pressure changes. This closed-loop feedback ensures accurate flow measurement by compensating for variations in flow character, maintaining precision without increasing system complexity.
Solution Approach 2:
The patent performs preliminary measurement of pressure changes in the reservoir before calculating flow rate. By measuring pressure changes over a defined time period and using this data to determine flow characteristics, the system establishes an accurate baseline measurement that compensates for flow variations before final flow rate calculation.
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 provides accurate and reliable flow and volumetric control of gas, reducing system complexity and cost while maintaining precise control over fluid displacement, suitable for applications like aspirating and dispensing operations.
Implementation Method 1
The pump may be a piezoelectric acoustic resonance pump
Implementation Method 2
highly controllable acoustic resonance pumps
Implementation Method 3
a first pressure sensor arranged to measure a pressure of the gas in the reservoir
Implementation Method 4
The second channel may comprise a flow restrictor which is configured to provide said flow restriction to a flow of gas between the reservoir and the first channel
Data Source
AI summary
A fluid control system comprising: a first channel for carrying a gas in and out of the fluid control system; a reservoir for said gas, wherein the reservoir includes a first pressure sensor arranged to measure a pressure of the gas in the reservoir; a pump for pumping said gas between the first channel and the reservoir, wherein the system is arranged such that a quantity of the gas displaced in the first channel depends on a change in pressure of the gas in the reservoir.