Pump-Based Fluid Flow Meter for Wide Dynamic Range Accuracy
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Solution Overview
Problem
Existing fluid flow meters face challenges in accurately measuring flow rates across a wide dynamic range, especially at low flow rates, where small leaks may be undetectable due to relative accuracy, and at high flow rates, where only large leaks are identifiable, due to the compressibility of gases and varying environmental conditions.
Innovation Solution
A fluid flow meter comprising a pump that displaces a near-fixed volume per cycle, a reservoir with sensors, and a control circuit that estimates fluid volume by counting pumping cycles, using non-volatile memory for calibration data across various operational conditions, allowing for absolute accuracy in flow measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If relative accuracy measurement is used, then high flow rate measurements are acceptable, but low flow rate measurements become inaccurate making small leaks undetectable
Solution Approach 1:
The flow measurement range is segmented into multiple ranges, with different pump speeds corresponding to different flow rate segments. The system automatically selects the appropriate pump speed based on the current flow rate, ensuring accurate measurement across the entire dynamic range from very low to high flow rates.
Solution Approach 2:
The pump speed is made dynamic and adjustable rather than fixed. The system can automatically change pump speed based on detected flow conditions, allowing the same pump to accurately measure both very low flow rates (for leak detection) and high flow rates by adapting its operating characteristics.
2Adaptability or versatility
If a single pump speed is used, then the device structure is simple, but the measurement range is limited and cannot cover both low and high flow rates accurately
Solution Approach 1:
A single pump is designed to perform multiple functions by operating at different speeds. The same pump mechanism can accurately measure both very low flow rates and high flow rates by adjusting its speed, eliminating the need for multiple specialized pumps or complex measurement systems.
Solution Approach 2:
The pump's operating parameters (speed) are changed based on the measurement requirements. By adjusting the pump speed according to the detected flow rate, the system maintains measurement accuracy across a wide dynamic range without increasing structural complexity.
3Measurement precision
If gas compressibility is considered, then measurement accuracy under varying pressure and temperature conditions improves, but the measurement system becomes more complex
Solution Approach 1:
The system replaces complex mechanical measurement mechanisms with a simpler pump-based displacement method. By measuring the actual volume of fluid pumped (which accounts for compressibility effects) rather than using mechanical flow sensors, the system achieves accurate measurements under varying pressure and temperature conditions with reduced complexity.
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
Enables accurate measurement of fluid flow rates from very low to high rates with absolute accuracy, effectively identifying both small and large leaks, regardless of environmental conditions, by using a pump with known displacement and sensors to trigger pumping cycles based on fluid levels.
Implementation Method 1
a pump adapted to pump a substantially near fixed amount (e.g. volume) of fluid per pumping cycle
Implementation Method 2
at least one sensor which may be functionally associated with the fluid collection reservoir and/or with the pump; and a control circuit/logic (controller) that may be adapted to trigger one or more pumping cycles, or a partial pumping cycle, in response to a signal from the at least one sensor. The signal of the at least one sensor may indicate a fluid amount (e.g. level or threshold) collected in the reservoir or in the pump.
Data Source
AI summary
A fluid flow meter comprising a fluid pump to displace fluid with pumping strokes of one or more pumping stroke types wherein each of the one or more stroke types displaces a known volume of fluid, a sensor functionally associated with a fluid reservoir and adapted to generate a signal indicative of a fluid pumping condition within the fluid reservoir, which fluid reservoir is integral or functionally associated with the pump, and circuitry to trigger one or a sequence of strokes of the pump in response to a signal from the sensor.