Sensor Vane Overload Protection for High-Pressure Flow Measurement
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Solution Overview
Problem
Conventional vortex flow meters fail to maintain integrity and accuracy under extreme conditions such as high temperatures (above 400°C) and pressures (above 140 bar) due to irreversible plastic deformation and pressure fluctuations caused by condensation-induced water hammers, leading to system failure.
Innovation Solution
The measuring system incorporates an overload protection device with a support bracket and stops to prevent plastic deformation, ensuring the sensor flag and deformation body remain elastic, using materials like stainless steel or nickel-based alloys, and is designed with gaps and projections to absorb pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the deformation body is made thin and flat with a high diameter-to-thickness ratio to achieve high measurement sensitivity, then the sensitivity to pressure fluctuations is improved, but the resistance to high dynamic pressures and ability to withstand pressure peaks is reduced
Solution Approach 1:
The deformation body is divided into two functional segments: a thin inner segment (bounded by the outer edge segment) that provides high measurement sensitivity, and a thicker outer edge segment that provides structural strength and pressure resistance. This segmentation allows each part to optimize its thickness for its specific function while working together as an integrated sensor assembly.
Solution Approach 2:
Different regions of the deformation body have different thickness characteristics: the inner segment has small thickness for high sensitivity to pressure fluctuations, while the outer edge segment has larger thickness for structural integrity and resistance to high dynamic pressures. This local variation in quality (thickness) resolves the contradiction between sensitivity and strength.
2Measurement precision
If the sensor assembly is designed to detect pressure fluctuations with high sensitivity, then the measurement accuracy is improved, but the reliability under extreme conditions (high temperature and pressure) deteriorates
Solution Approach 1:
The sensor assembly is segmented into the measurement-critical inner segment and the protection-critical outer edge segment, allowing the thin inner segment to maintain high measurement accuracy while the thicker outer segment ensures reliability under extreme conditions.
Solution Approach 2:
The deformation body is made from high-strength nickel-based alloy (e.g., Inconel 718) that maintains both the sensitivity required for accurate measurement and the strength required for reliability under extreme temperatures and pressures.
3Strength
If the deformation body thickness is increased to withstand high dynamic pressures, then the pressure resistance is improved, but the measurement sensitivity is reduced
Solution Approach 1:
The deformation body is segmented such that the inner segment maintains small thickness for high measurement sensitivity while the outer edge segment provides increased thickness for pressure resistance, allowing both requirements to be satisfied simultaneously in different regions.
Solution Approach 2:
The thickness of the deformation body varies locally: thin in the inner segment for sensitivity and thicker in the outer edge segment for pressure resistance, resolving the contradiction between these two opposing requirements.
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 system maintains measurement accuracy and integrity by preventing irreversible deformation, allowing operation in extreme conditions with high dynamic pressures and temperatures.
Implementation Method 1
the sensor vane performs pendulum movements in the detection direction, elastically deforming the deformation body
Implementation Method 2
generates vortices arranged in a so-called Kärmännian vortex street within the portion of the fluid flow flowing immediately downstream of the baffle body
Implementation Method 3
formed, for example, by means of a capacitor mechanically coupled to or integrated into the sensor assembly or by means of a piezo stack serving as a piezoelectric transducer
Data Source
Figure 1
Figure 2
Figure 3a~3d
AI summary
The invention relates to a sensor assembly (11) comprising a deformation element (111) with two opposing surfaces (111+, 111#), an outer edge segment (111a), and a sensor vane (112) which extends from the surface (111+) up to a distal end and which comprises a left-side first lateral surface (112+) and a right-side second lateral surface (112#). The sensor assembly (11) further comprises an overload protection device (113), which extends from said edge segment (111a) up to a distal end, can be used to protect the deformation element (111) against plastic or irreversible deformation, and comprises a support bracket (113a) that is guided at a lateral distance from the sensor vane, and two stops (113b, 113c), which are supported on the support bracket for the sensor vane (112), wherein a first stop (113b) of the stops is placed on the left-hand side of the sensor vane and a second stop (113c) of the stops is placed on the right-hand side of the sensor vane. The stops (113b, 113c) are dimensioned and arranged such that an intermediate space (113') formed between the stops takes up solely a sub-region (112a) of the sensor vane (112). The deformation element and the sensor vane are additionally designed to vibrate about a common static rest position and in the process move relative to the overload protection device such that the sensor vane carries out oscillating movements which elastically deform that deformation element and during which the sub-region (112a) is alternately moved to the left, namely in the direction of the stop (113b), or to the right, namely in the direction of the second stop (113c). A sensor made with such a sensor assembly and a transducer element (12), which is coupled thereto and functions so as to generate a sensor signal that represents temporally changing movements of the sensor vane and/or temporally changing deformations of the membrane, or a measuring system made with said sensor and a measuring electronic system connected thereto can be used to detect pressure fluctuations in a flowing fluid, for example in a steam with an at least temporary temperature of 400 ºC and/or an at least temporary pressure of more than 140 bar, in order to measure a flow parameter of said fluid for example.