Fluid System Flow Estimation Without Flowmeters
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Solution Overview
Problem
Flowmeters are expensive and require a long straight pipe for precision, increasing construction and installation costs, as well as space requirements in fluid systems.
Innovation Solution
A fluid system with a bypass circuit that uses a rotating electrical machine and a flow rate control valve, controlled by a device estimating flow rate and effective height difference to manage total flow rate without a flowmeter, allowing for cooperative control to achieve target flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flowmeter is installed to control total flow rate, then flow rate measurement precision is improved, but device cost and installation space increase
Solution Approach 1:
The patent introduces a mediator (the relationship between generator characteristics and flow rate) to indirectly obtain flow rate information without directly measuring it with a flowmeter. The control device uses the generator's rotational speed and output characteristics as intermediate parameters to estimate the total flow rate, thereby avoiding the need for expensive and space-consuming flowmeters while maintaining sufficient measurement precision for control purposes
Solution Approach 2:
The patent replaces the mechanical flow measurement system (flowmeter with straight pipe requirements) with an electrical measurement system. By measuring the generator's electrical characteristics (rotational speed, output power) which correlate with flow rate, the system substitutes a complex mechanical measurement approach with a simpler electrical measurement approach, reducing both device complexity and installation space requirements
2Manufacturing precision
If a flowmeter is installed to detect flow rate, then flow rate control accuracy is improved, but construction cost increases
Solution Approach 1:
The patent uses generator characteristics (rotational speed, output power) as intermediate parameters to indirectly determine flow rate. By establishing the relationship between these generator parameters and flow rate, the system achieves accurate flow rate control without the high construction costs associated with installing and calibrating precision flowmeters
Solution Approach 2:
The system utilizes the generator's own operational characteristics to provide flow rate information. The generator essentially serves itself by providing the data needed for flow rate control through its own performance parameters, eliminating the need for separate expensive flow measurement equipment
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 costs and space requirements by eliminating the need for flowmeters, enables precise flow rate estimation, and ensures efficient operation of the fluid system.
Implementation Method 1
a water turbine (W) installed in a pipe system (1) which has a height difference and through which water flows
Implementation Method 2
a generator (G) connected to a rotation shaft (9) of the water turbine (W)
Data Source
AI summary
A control device estimates a flow rate and an effective height difference of a fluid machine based on a characteristic detectable with regard to a rotating electrical machine and correlating with the flow rate and the effective height difference of the fluid machine. A total flow rate in a pipe system is estimated based on these values estimated by the control device and a flow resistance characteristic line, and cooperative control of the fluid machine and the flow rate control valve is performed such that the estimated value of the total flow rate becomes close to a target flow rate of the total flow rate in the pipe system.