Electromagnetic Flowmeter Conductivity Sensing via Voltage-Amplitude Impedance
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Solution Overview
Problem
Traditional conductivity meters face challenges with low measuring precision and stability due to noise interference and limited measuring range, especially when dealing with low-conductivity liquids, and struggle to generate small induced currents effectively.
Innovation Solution
An electromagnetic flowmeter with a voltage-amplitude conductivity-sensing function, comprising a microprocessor, transducer, exciting-current generating device, flow-sensing device, and voltage-amplitude conductivity measuring device, which uses a switch to alternate between measuring flow rate and conductivity, and employs a sine oscillation voltage pulse to calculate impedance and conductivity, adjusting current values as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional constant current source or Wheatstone bridge structure is used for conductivity measurement, then the device structure is simple, but the measurement precision and stability deteriorate due to noise interference and limited measuring range
Solution Approach 1:
The patent divides the measurement system into separate functional modules: excitation signal generation, impedance measurement, and conductivity calculation. The microprocessor controls switching between different measurement modes (flow rate measurement and conductivity measurement), allowing each module to be optimized independently while maintaining overall system precision
Solution Approach 2:
The patent replaces traditional electrical measurement methods (constant current source, Wheatstone bridge) with an impedance-based measurement system using sine oscillation voltage pulses. This substitution enables higher measurement precision by avoiding the noise and ripple issues inherent in traditional electrical measurement circuits
2Adaptability or versatility
If constant induced current is used for conductivity measurement, then the measuring range is limited, but the device complexity remains low
Solution Approach 1:
The patent implements dynamic switching between different measurement modes (flow rate measurement and conductivity measurement) controlled by a microprocessor. The system can adaptively select the appropriate measurement mode based on the application requirements, expanding the overall measuring range without requiring multiple dedicated devices
Solution Approach 2:
The electromagnetic flowmeter is designed to perform multiple functions: both flow rate measurement and conductivity measurement. By integrating both measurement capabilities into a single device with microprocessor control, the patent achieves versatility without proportionally increasing device complexity
3Measurement precision
If small induced current is generated for low-conductivity liquid measurement, then the measurement capability for low-conductivity liquids is improved, but it becomes difficult to manufacture due to generation challenges
Solution Approach 1:
The patent replaces the difficult-to-manufacture small induced current generation method with an impedance-based measurement approach using sine oscillation voltage pulses. This substitution maintains the ability to measure low-conductivity liquids while significantly easing manufacturing requirements
Solution Approach 2:
The patent changes the measurement parameter from direct current measurement to impedance measurement using alternating voltage pulses. This parameter change enables the measurement of low-conductivity liquids by measuring the impedance characteristics rather than relying on small induced currents, thereby improving measurement capability while simplifying manufacturing
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 solution enhances the precision and stability of conductivity measurements by reducing noise interference and expanding the measuring range, allowing for accurate flow rate and conductivity sensing even in low-conductivity liquids, while preventing errors in conductivity determination.
Implementation Method 1
an exciting-current generating device (4), a flow-sensing device (5)... The first microprocessor (6) is configured to drive the exciting-current generating device (4) to generate an exciting current
Implementation Method 2
Conductivity refers to the ability of materials to transmit the current. The conductivity of a liquid is relevant to the concentration of the dissolved ions
Data Source
AI summary
An electromagnetic flowmeter with voltage-amplitude conductivity-sensing function for a liquid in a tube includes a first microprocessor, a transducer, flow-sensing device, an exciting-current generating device, a voltage-amplitude conductivity-sensing device, and a switch. The transducer includes coils and sensing electrodes. The switch is electrically connected to the first microprocessor and the sensing electrode. The switch is selectively connected to the flow-sensing device or the voltage-amplitude conductivity-sensing device according to the signals sent from the microprocessor. The microprocessor drives the exciting-current generating device to generate an exciting current when the switch is connected to the flow-sensing device. The microprocessor stops the exciting-current generating device from generating exciting current and computing conductivity of liquid when the switch is electrically connected to the voltage-amplitude conductivity-sensing device.