Vibrating Sheet Welding for Coriolis Flow Meters
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Solution Overview
Problem
Existing Coriolis mass flow meters and vibrating tube density meters face issues with stress concentration and residual stress due to conventional welding techniques, leading to reduced structural strength, inaccurate measurements, and short service life, particularly because annular welds create stress-sensitive regions prone to breakage and interference from in-phase vibrations.
Innovation Solution
The design of a vibrating sheet with a spatial structure, where welds are only formed in stress-insensitive regions, avoiding the stress-sensitive areas and allowing for enhanced strength and reduced residual stress, enabling the use of various welding methods like manual argon arc welding instead of vacuum brazing, which simplifies the process and improves measurement precision and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional welding techniques (argon arc welding) are used to connect the vibrating sheet to the flow tube, then the welding process is simple and energy-efficient, but stress concentration and residual stress occur at the weld location leading to reduced structural strength
Solution Approach 1:
The patent applies local quality by creating a localized recess in the vibrating sheet at the weld location, changing the geometric properties only where needed. This recess modifies the stress distribution locally to reduce stress concentration while maintaining the simplicity of argon arc welding. The recess acts as a stress-relief feature that prevents crack initiation and propagation at the weld zone.
2Stability of the object's composition
If vacuum brazing is used to connect the vibrating sheet to the flow tube, then residual stress is minimized, but the process is complex and energy-consuming with quality control issues
Solution Approach 1:
The patent extracts the problematic aspect of vacuum brazing (residual stress) while eliminating its associated complexity. By combining the recess design with simple argon arc welding, the invention achieves low residual stress without requiring vacuum brazing. The recess structure inherently reduces stress concentration, making the simpler welding process sufficient to achieve the desired stress state.
3Reliability
If annular welds are formed around the flow tube, then the connection is complete, but stress-sensitive regions are created that are prone to breakage and interference from in-phase vibrations
Solution Approach 1:
The patent applies local quality by creating a localized recess in the vibrating sheet at the weld location, changing the geometric properties only where needed. This recess modifies the stress distribution locally to reduce stress concentration while maintaining the simplicity of argon arc welding. The recess acts as a stress-relief feature that prevents crack initiation and propagation at the weld zone.
4Stability of the object's composition
If the vibrating sheet is welded to the flow tube, then the structure is stable, but stress concentration occurs at the weld location reducing service life
Solution Approach 1:
The patent applies preliminary action by pre-forming a recess in the vibrating sheet before welding. This preliminary geometric modification creates a stress-relief structure that is already in place before the welding process. The recess is designed to accommodate the weld and prevent stress concentration from the outset, thereby extending service life without compromising structural stability.
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 significantly increases the service life of Coriolis mass flow meters and vibrating tube density meters by minimizing stress concentrations and residual stress, allowing for precise measurements without the limitations of vacuum brazing, and simplifies the welding process, reducing energy consumption and quality control issues.
Implementation Method 1
the flow tube of the Coriolis mass flow meter vibrates in an inherent mode when in operation, thereby generating a corresponding resonance frequency
Implementation Method 2
When the liquid in the flow tube flows, a Coriolis acceleration is generated on the flow tube due to the presence of the Coriolis effect
Data Source
AI summary
The present invention relates to a Coriolis mass flow meter, a vibrating tube density meter and a vibrating sheet used therein, and more particularly, to a vibrating sheet for use in a Coriolis mass flow meter or a vibrating tube density meter, the vibrating sheet having at least one welded connecting portion that is fixedly welded to the flow tube of the Coriolis mass flow meter or the vibrating tube density meter, the flow tube being excited to vibrate around a revolving axis at the welded junction of the vibrating sheet and the flow tube. The welded connecting portions of the vibrating sheet are only formed in the stress insensitive region of the vibrating sheet, wherein the stress insensitive region is the region of the vibrating sheet which has an angle of not more than 45 degrees with respect to the revolving axis. In addition, the present invention also provides a Coriolis mass flow meter and a vibrating tube density meter using the vibrating sheet. The present invention not only simplifies the process, but also improves the measurement precision and service life of the Coriolis mass flow meter and the vibrating tube density meter.