Cryogenic ECVT Sensor with Shielded Electrode Sleeve
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Solution Overview
Problem
Existing electrical capacitance volume tomography (ECVT) devices are sensitive to external interference and challenging to install on variable-diameter pipelines, especially when measuring cryogenic two-phase flows, due to the close liquid-gas dielectric constant ratio and lack of effective shielding and simple installation methods.
Innovation Solution
The ECVT device for a cryogenic Venturi tube features an integrated electrode plate sleeve with curved electrode plates, a metal shell for shielding, and a conductor rod with wire slots for secure and interference-free measurements, allowing for simple assembly and disassembly, and maintaining the relative position of electrode plates during measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ECVT sensor structure is used for cryogenic fluid measurement, then the liquid-gas dielectric constant ratio is small (within 1.5), but the device becomes very sensitive to external interference during measurement
Solution Approach 1:
The patent introduces a shielding structure as an intermediary element between the electrode plates and the external environment. This shielding structure acts as a mediator that blocks external electromagnetic interference from reaching the sensitive measurement components, thereby resolving the contradiction between maintaining measurement precision and reducing sensitivity to external interference in cryogenic fluid measurements
Solution Approach 2:
The patent applies preliminary anti-action by pre-installing shielding structures and grounding systems before measurement begins. The shielding structure is positioned in advance to prevent external interference from affecting the measurement, and grounding connections are established beforehand to provide a reference potential that counteracts interference effects
2Adaptability or versatility
If variable-diameter pipeline (Venturi tube) is used for cryogenic fluid flow, then the pipeline structure is complex, but the installation of electrode plates becomes more difficult
Solution Approach 1:
The patent divides the electrode plate assembly into multiple separate electrode plates that can be individually installed onto the Venturi tube surface. This segmentation allows each plate to be positioned and fixed independently according to the variable diameter contour of the pipeline, making the installation process feasible despite the complex geometry
Solution Approach 2:
The patent applies local quality by customizing the position, size, and shape of individual electrode plates to match the local geometry of the Venturi tube at different sections. Each electrode plate is designed with specific dimensions and mounting features suitable for its location on the variable-diameter pipeline, enabling precise installation despite the overall structural complexity
3Ease of operation
If electrode plates are installed on variable-diameter pipeline without integrated structure, then installation is challenging, but the relative position of plates may not be maintained during measurement
Solution Approach 1:
The patent merges multiple electrode plates and their mounting structures into an integrated assembly that is pre-configured with fixed relative positions. This combined structure is then installed as a single unit on the Venturi tube, simplifying the installation process while ensuring that the relative positions of all electrode plates remain stable and predetermined during measurement operations
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 design enhances measurement accuracy by reducing external interference, simplifies the installation of electrode plates on variable-diameter pipelines, and provides effective electromagnetic shielding, enabling precise phase distribution imaging of cryogenic two-phase flows from room temperature to hypothermic conditions.
Implementation Method 1
measuring the capacitances between multiple plates
Implementation Method 2
uses the spatial difference of a dielectric constant caused by different phase distributions in the tube
Implementation Method 3
a good shielding device should be used in a sensor design
Data Source
AI summary
Disclosed is an electrical capacitance volume tomography applied to flow monitoring in a Venturi tube of a cryogenic fluid (such as liquid nitrogen (˜78K) and liquid oxygen (˜90K)). The device includes a conductor rod, a metal shell, a Venturi tube, an electrode plate sleeve, an electrode plate and annular connecting shells. According to the device, an electrode plate and electrode plate sleeves which are attached to the surface of a Venturi tube are arranged according to the variable-diameter characteristic of the Venturi tube, meanwhile, a corresponding wire connecting structure is designed, and a shielding shell is designed according to the characteristic that electrical capacitance volume tomography needs shielding. The device has the advantages of being simple and stable in structure, easy to disassemble and assemble, capable of being disassembled and assembled many times and capable of being rapidly connected with other pipelines.