Coriolis Mass Flow Sensor Actuator Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Coriolis mass-flow-rate sensors are insufficiently precise in environments with strong vibrations, such as internal combustion engines, and are incompatible with high flow rates required by vehicles and aircraft due to miniaturization issues and sensitivity to impurities.
Innovation Solution
A device with a flow tube and actuators that modify the tube's cross-section to apply Coriolis forces independently of the tube's modulus of elasticity, using piezoelectric or piezoresistive sensors to measure forces perpendicular to the flow path, and a control circuit to maintain constant cross-sectional area and excite the fluid at frequencies above the system's main vibration range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Coriolis mass-flow-rate sensor uses a tube vibrated at its resonant frequency to measure mass flow rate, then measurement precision is improved, but sensitivity to environmental vibrations increases
Solution Approach 1:
The patent changes the operating frequency parameter from the tube's resonant frequency (hundreds of Hz) to a much higher frequency (several kHz). This parameter change allows the system to operate above environmental vibration frequencies, eliminating sensitivity to such disturbances while maintaining measurement precision through the Coriolis effect at the new operating frequency
Solution Approach 2:
The actuator applies a preliminary periodic force to the fluid at a frequency higher than environmental vibrations before measurement occurs. This preliminary excitation of the fluid creates the necessary Coriolis conditions independent of tube resonance, allowing measurement to proceed without being affected by environmental vibrations
2Object-affected harmful factors
If a Coriolis mass-flow-rate sensor is miniaturized to operate at higher frequencies, then sensitivity to environmental vibrations is reduced, but compatibility with high flow rates is lost
Solution Approach 1:
The patent extracts the excitation function from the tube structure and applies it directly to the fluid through an actuator. By taking out the tube from the measurement equation (measuring fluid response rather than tube response), the system can use small-diameter tubes for high-frequency operation while still handling large flow rates, as the measurement depends on fluid motion not tube size
Solution Approach 2:
The patent replaces the mechanical tube vibration system with a fluid excitation system. Instead of mechanically vibrating the tube at high frequency, an actuator applies force directly to the fluid, substituting the mechanical resonance approach with a more direct fluid dynamics approach that is not constrained by tube dimensions
3Measurement precision
If a Coriolis mass-flow-rate sensor uses a small-diameter tube to operate at high frequencies, then measurement precision is improved, but risk of clogging increases
Solution Approach 1:
The patent extracts the measurement function from the tube wall vibrations and places it in the fluid itself. By measuring the fluid's response to actuator excitation rather than tube vibrations, the system can use small-diameter tubes for precise high-frequency operation without the tube being susceptible to clogging, as the measurement mechanism does not depend on the tube's mechanical response
Solution Approach 2:
The actuator serves as an intermediary that applies force directly to the fluid, bypassing the need for tube vibrations. This intermediary mechanism allows the use of small-diameter tubes for precision measurement while the actuator's direct fluid coupling prevents clogging issues that would affect tube-based vibration systems
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
The solution provides high precision and insensitivity to vibrations, enabling accurate mass flow rate measurement at high flow rates while reducing the risk of clogging and improving system longevity by exciting the fluid rather than the tube.
Implementation Method 1
The actuators are configured to modify a cross-section of the tube in the transverse plane... to apply Coriolis forces independently of the tube's modulus of elasticity... excite the fluid rather than the tube
Implementation Method 2
using piezoelectric or piezoresistive sensors to measure forces perpendicular to the flow path
Implementation Method 3
using piezoelectric or piezoresistive sensors to measure forces perpendicular to the flow path
Data Source
AI summary
A device for measuring the mass flow rate, including a flow pipe; a first set of actuators which are arranged in a first plane including a first transverse cross section of the pipe and perpendicular to the fluid flow path, these being configured to move selectively in the first plane; a control circuit configured to control a movement of the first and second actuators so that the cross-sectional area for flow through the pipe in the first plane remains constant; a measurement sensor measuring a force or a stress in a direction perpendicular to the flow path, in the vicinity of the actuators of the first set along the flow path; a computation device configured to calculate the mass flow rate passing through the flow pipe as a function of the force or stress measured by the sensor.