A flow capacitance tomography device in a cryogenic fluid tube

Abstract

The invention discloses a cryogenic fluid tube flow capacitance tomography device, which is applied to the capacitance tomography imaging of deep low temperature fluid (such as liquid nitrogen (~78K), liquid oxygen (~90K)) tube flow pattern monitoring. The device includes: insulating pipes, electrode sheets, limit sleeves, shielding partitions, electromagnetic shielding covers, shielding rings, and fastening studs. The device sets fastening studs for the shrinkage of materials at low temperatures to maintain the adhesion between electrode sheets and insulating pipes, and at the same time designs a shielding structure for the characteristics of low-temperature fluids with close dielectric constants. This cryogenic fluid capacitance tomography device has the following characteristics: simple structure, quick disassembly and assembly, and convenient connection with other pipelines in the system; it can be used in a wide range from room temperature to deep low temperature, and multiple large-scale temperature cycles will not affect the measurement Accuracy: high positioning accuracy, good electromagnetic shielding effect.

Description

technical field [0001] The invention relates to the fields of low-temperature refrigeration engineering technology and sensor science and technology, in particular to an electric capacitance tomography (ECT) device for flow in a low-temperature fluid tube. Background technique [0002] Two-phase flow in pipes often occurs in fluid-related industries such as chemical industry and air separation, and involves design optimization and operation safety. Therefore, the detection of two-phase distribution is of great significance. Electrical Capacitance Tomography (ECT) technology utilizes the characteristics of different total dielectric constants of different phase contents in micro-elements in the field, and measures the capacitance value between two pairs of multi-pole plates, and uses the inversion algorithm to analyze the in-field Solving and imaging the phase distribution of the fluid in each micro-element is a non-invasive measurement technology, which has the advantages of...

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Problems solved by technology

[0006] Chinese patent CN102364420B discloses a high-precision ECT smart sensor. The sensor part of the invention is perforated on the insulating pipe, the electrode piece directly contacts the fluid, and the electrode piece is fixed by bolts, which is quite different from the structure of the present invention.

[0007] Chinese patent CN104655692B discloses a structural design of an ECT sensor that uses a two-layer frame to fix the electrode sheets. In this invention, there is no shielding plate on the ring, and the shielding structure is installed on the outer frame and corresponds to the pole pieces one by one. It is structurally different from the present invention. big difference

[0008] Chinese patent CN106932446A discloses an ECT sensor with built-in electrodes in the tube. In this invention, some electrode sheets are installed inside the tube, and the applicable tube structure is a tube with a concentric structure, which has a larger structure than the present invention. difference

[0012] US Patent US7496450B2 discloses a multiphase flow imaging monitoring method based on electrical capacitance tomography technology. This patent specifies the distribution of sensors but does not design the installation structure of the sensors, and does not design the shielding plate in the circumferential direction. There is a big difference in this patent

[0013] U.S. Patent US8461852B2 discloses a method for monitoring particle distribution in a fluidized bed based on electrical capacitance tomography technology. The electrodes of the ECT sensor are fixed by being embedded in the outer wall of the pipeline, which is structurally different from the structure of this patent. big difference

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