Coriolis Flowmeter Nodal Plate Vibration Suppression
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Solution Overview
Problem
Coriolis mass flowmeters face challenges in achieving high measurement accuracy due to susceptibility to spurious vibrations, which affect the precision of mass throughput detection.
Innovation Solution
The implementation of nodal plates connected to the housing structure on both the inlet and outlet sides of the Coriolis mass flowmeter, with additional nodal plates forming vibration nodes and connected to the housing to suppress unwanted vibration modes, thereby shifting them away from the operating frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If nodal plates are connected to the housing structure on inlet and outlet sides, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The nodal plates are pre-positioned and connected to the housing structure before the measuring tubes are installed. This preliminary action establishes the vibration node positions in advance, ensuring that unwanted vibration modes are suppressed from the outset, thereby improving measurement accuracy without requiring complex adjustments during operation.
Solution Approach 2:
The nodal plates act as intermediary elements between the housing structure and the measuring tubes. By connecting to the housing structure through these intermediary nodal plates, the system effectively decouples the measuring tubes from direct housing vibrations, improving measurement accuracy while maintaining a modular structure that manages complexity.
2Measurement precision
If additional nodal plates are added to suppress unwanted vibration modes, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
The vibration suppression function is segmented into multiple independent nodal plates positioned at different locations (inlet side and outlet side). Each nodal plate independently suppresses specific unwanted vibration modes, allowing the system to achieve high measurement precision through modular addition rather than requiring a complex integrated vibration suppression system.
Solution Approach 2:
Each nodal plate is designed with specific local properties (thickness, material, geometry) optimized for its particular position in the flow direction. The inlet-side nodal plate and outlet-side nodal plate have different characteristics tailored to the local vibration modes at each position, enabling effective vibration suppression while maintaining manufacturing simplicity through standardized local solutions.
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 configuration enhances measurement accuracy by preventing simultaneous oscillation of measuring tubes in undesirable directions and frequencies, improving the precision of mass flow rate measurement.
Implementation Method 1
the measuring tube is excited to vibrate with a vibration generator or with several vibration generators - in particular with the natural frequency of a specific natural mode of a vibration
Implementation Method 2
Coriolis mass flowmeters allow the mass flow rate of the medium flowing through the measuring tube to be determined with high accuracy
Implementation Method 3
the actuator arrangement for generating vibrations and the sensor arrangements for detecting vibrations are generally constructed in such a way that they have a permanent magnet and a magnetic coil in order to transmit vibrations electrically to the measuring tube
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The flow meter (1) comprises curved measurement tubes (2), actuator arrangement, sensor arrangement and housing structure (5). The measurement tubes are connected to an inlet end portion and an outlet end portion by oscillation node plates (3,4). The oscillation node plates are connected to the housing structure through inlet end portion and outlet end portion.