Fluid Pump Calibration via Flow-Pressure Characterization
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Solution Overview
Problem
Conventional sensorless fluid pump arrangements lack accuracy in calibration, as they do not measure fluid pressure directly, leading to inefficiencies and potential operational issues due to component tolerances and wear over time.
Innovation Solution
A method involving setting volume flows and determining associated pump flows during phases of increasing and decreasing pressure to generate pairs of values, which allow for calibration of fluid pressure without a pressure sensor, using a pressure regulator unit to establish required fluid pressures and pump currents, and accessing characteristic curves to adjust pump operation parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is installed in the fluid discharge line to directly measure fluid pressure, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a pressure regulator unit as an intermediary component that establishes a known relationship between pump flow and fluid pressure. By measuring pump flow through the pressure regulator unit, the system indirectly determines fluid pressure without requiring a pressure sensor in the discharge line, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent replaces the mechanical/electronic pressure sensing system with a flow-based measurement approach. By using the known characteristics of the pressure regulator unit and measuring pump flow instead of directly measuring pressure, the system achieves pressure determination without complex pressure sensing infrastructure
2Device complexity
If conventional sensorless calibration methods are used to simplify the system, then device complexity is reduced, but manufacturing precision and calibration accuracy deteriorate due to component tolerances and wear
Solution Approach 1:
The patent implements a preliminary calibration phase where the control unit determines multiple pairs of values for volume flow and pump flow at different operating points before normal operation. This preliminary action establishes accurate calibration data that compensates for component tolerances and wear, improving manufacturing precision without adding complex real-time measurement systems
Solution Approach 2:
The patent uses feedback by comparing measured pump flow with expected flow based on pump motor speed and established calibration curves. The control unit adjusts pump motor operation based on this feedback to maintain accurate fluid pressure delivery, compensating for component variations and wear over time
3Measurement precision
If multiple calibration phases with increasing and decreasing pressure are implemented to improve calibration accuracy, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent employs periodic action by implementing calibration at multiple phases (increasing and decreasing pressure) to capture hysteresis effects and establish more accurate calibration data. While this increases calibration time, it significantly improves calibration accuracy by accounting for pressure-dependent variations in system behavior
Solution Approach 2:
The patent performs more calibration measurements than the minimum single-point calibration would require, collecting multiple pairs of volume flow and pump flow values at different operating points. This excessive action in terms of measurement quantity improves calibration accuracy by providing more data points for establishing reliable calibration curves
Data Source
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AI summary
The invention relates to a method for calibrating a fluid pump arrangement (100), having the following steps: adjusting (S1) a volumetric flow rate in a fluid discharge line (116) of the fluid pump arrangement (100); ascertaining (S2) a fluid pressure, corresponding to the volumetric flow rate, in the fluid discharge line (116); and ascertaining (S3) a pump flow, corresponding to the volumetric flow rate, of a pump motor (120) of the fluid pump arrangement (100). The preceding steps S1, S2, and S3 are each carried out during a first phase of increasing fluid pressure in the fluid discharge line (116) in order to ascertain a first value pair from the volumetric flow rate and the pump flow and during a second phase of decreasing fluid pressure in the fluid discharge line (116) in order to ascertain a second value pair from the volumetric flow rate and the pump flow.