Centrifugal Pump Flow Monitoring via Motor Electrical Parameters
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Solution Overview
Problem
Existing methods for monitoring the hydraulic operating point of centrifugal pumps, especially in complex systems like sewage technology, are inefficient and prone to errors due to the complexity of flow rate measurement and reliance on indirect calculations.
Innovation Solution
A method that determines characteristic values using electrical variables of the motor and pressure generated by the pump by approaching multiple operating points, allowing for accurate recording of hydraulic parameters without the need for flow monitors, using parametric equations to model pump behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow monitors or flow sensors are arranged to record the flow within the pump, then the flow rate can be detected, but the arrangement becomes complex and often prone to failure
Solution Approach 1:
The invention extracts the flow measurement function from direct flow monitoring and relocates it to power consumption measurement of the motor. By measuring electrical parameters (power, current, voltage) that correlate with flow rate through the pump's performance curves, the complex flow monitoring arrangement is replaced with simple electrical sensing already present in the motor control system.
Solution Approach 2:
The invention introduces an intermediary relationship between power consumption and flow rate through the pump's hydraulic performance curves. Instead of directly measuring flow, the system uses power consumption as an intermediary parameter that can be easily measured electrically and then converted to flow rate information using predetermined curve relationships between these variables.
2Measurement precision
If indirect calculation of flow rate is performed by determining the fill level of the shaft, then flow rate can be determined, but the method becomes complex and requires additional time measurements
Solution Approach 1:
The invention replaces the mechanical/physical measurement approach (fill level determination with pressure sensors and time measurements) with an electrical measurement approach. By measuring motor power consumption, current, and voltage, the system eliminates the need for mechanical fill level sensors, pressure measurements, and time-based calculations, simplifying the overall measurement system.
3Measurement precision
If multiple operating points are approached to determine characteristic values, then accuracy of hydraulic parameters increases, but measurement time and complexity increase
Solution Approach 1:
The invention performs preliminary action by pre-determining the characteristic curves (performance curves) of the pump during manufacturing or initial calibration. These curves establish the relationships between power consumption, flow rate, head, and efficiency. During actual operation, the system only needs to measure current power consumption and use the pre-stored curves to immediately determine flow rate and other hydraulic parameters, eliminating the need for repeated multi-point measurements.
Data Source
AI summary
The method involves providing rotational speed controller on the basis of electrical parameters of the motor and generating a pressure by a pump. Delivered amounts are determined on a system side at set operating points to determine the characteristic values.