Frequency Converter Pump Flow Control via Torque Detection
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Solution Overview
Problem
Existing pump drive systems connected to containers face issues with overheating and damage due to inconsistent flow, and reliance on measuring sensors that can be unreliable and costly to maintain.
Innovation Solution
A method utilizing a frequency converter to adjust pump flow based on estimated mean incoming flow, eliminating the need for surface level sensors by detecting container emptiness through torque changes and calculating the incoming flow using drainage times and pump performance curves, allowing for efficient and cost-effective operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface measuring sensors (ultra-sound or pressure) are used to control pump flow, then accurate surface level data can be obtained, but the reliability of operation decreases due to sensor breakage and additional costs increase
Solution Approach 1:
The patent removes the external measuring sensors from the system entirely. Instead of using ultra-sound or pressure sensors to measure surface level, the invention extracts the measurement function by using the pump drive's own torque measurements to infer flow conditions and control pumping based on estimated mean incoming flow, eliminating the problematic sensors that cause reliability issues and additional costs
Solution Approach 2:
The pump drive system performs its own measurement function using its built-in torque sensing capability. The frequency converter measures torque during pumping operations, and this torque data is used to estimate the mean incoming flow and control the pump without requiring external sensors. The system serves itself by using its operational parameters for both pumping control and flow measurement
2Use of energy by moving object
If the pump operates at constant power without flow through the pump, then energy efficiency may be maintained, but overheating occurs causing damage to the pump drive
Solution Approach 1:
The patent implements dynamic power adjustment instead of constant power operation. The frequency converter continuously adapts the pump's power consumption based on real-time torque measurements and estimated mean incoming flow. This dynamic control ensures the pump operates efficiently by matching power output to actual flow conditions, preventing both energy waste and overheating that would occur with constant high-power operation
Solution Approach 2:
The system uses torque measurements from the frequency converter as feedback to control pump operation. The measured torque during pumping provides information about the actual flow conditions, which feeds back to the frequency converter to adjust power supply. This closed-loop feedback ensures the pump receives adequate flow to prevent overheating while maintaining energy efficiency by avoiding unnecessary high-power operation
3Measurement precision
If measuring sensors and cabling are installed for pump control, then surface level measurement is achieved, but installation and service costs increase
Solution Approach 1:
The frequency converter performs multiple functions: it controls the pump motor, measures torque during operation, estimates mean incoming flow, and provides the control signal for pump operation. By making the frequency converter multi-functional, the patent eliminates the need for separate measuring sensors and cabling, reducing installation complexity and service costs while maintaining the ability to measure and control flow based on surface level conditions
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
This approach reduces the risk of overheating, minimizes sensor-related failures, and lowers installation and maintenance costs by maintaining reliable pump operation without the need for additional level measurement devices.
Implementation Method 1
detecting container emptiness through torque changes
Data Source
AI summary
A method in connection with a pump drive connected to a container or the like, wherein a frequency converter is arranged to supply power to a pump in such a manner that a pump flow (Qp) is responsive to an estimated mean incoming flow (Qest) to the container. The method includes draining the container, allowing the container to fill during a predefined filling time (tfill) while the pump is inactive, draining the container again at a known pump flow (Qp,nom), defining the drainage time (tdrain), defining an estimated mean incoming flow (Qest) on the basis of the filling time (tfill), drainage time (tdrain) and known pump flow (Qp,nom), and setting the power supplied by the frequency converter to the pump to be such that the pump flow (Qp) corresponds to the produced estimated mean incoming flow (Qest).