Electrical capacitance volume tomography device for cryogenic fluid flowing in venturi tube

Patent metadata

Field	Value
Publication number	US-2022221417-A1
Application number	US-202217706596-A
Country	US
Kind code	A1
Filing date	Mar 29, 2022
Priority date	Apr 29, 2020
Publication date	Jul 14, 2022
Grant date	—

Abstract

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 comprises 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.

First claim

What is claimed is:

1 . An electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube, comprising a conductor rod, a metal shell, a Venturi tube, electrode plate sleeves, an electrode plate and annular connecting shells;
wherein two electrode plate sleeves are provided, which form a complete electrode plate device, and an inner surface of the electrode plate device is matched with an outer surface of the Venturi tube and is fixed tightly attached to the outer surface of the Venturi tube; the electrode plate sleeve is provided with a plurality of electrode plate grooves, the shape of which is matched with that of the electrode plate, and the electrode plate is installed tightly attached to the plurality of electrode plate grooves of the electrode plate sleeve; two annular connecting shells are provided which form a complete connecting shell device; a peripheral circular diameter of two ends of the electrode plate device is equal to an outer diameter of the connecting shell device, and the two ends of the electrode plate device are fixedly connected with two ends of the connecting shell device, respectively; the annular connecting shell is provided with a plurality of metal hemispheres; the electrode plate on the electrode plate sleeve is welded with the plurality of metal hemisphere through wires; the metal shell is provided with a plurality of semi-cylindrical grooves matched with the metal hemispheres, an inner diameter of the metal shell is equal to an outer diameter of the connecting shell device, and the metal shell sleeves the circumference of the connecting shell device and is fixed through the plurality of semi-cylindrical grooves; the metal shell is provided with a round hole for installing the conductor rod; the inside of the conductor rod is a metal conductor, the periphery of the conductor rod is wrapped with an insulating material, and the bottom of the conductor rod is provided with an elastic metal sheet, and a maximum diameter of the conductor rod is the same as that of the round hole on the metal shell and larger than that of the semi-cylindrical groove on the metal shell; the conductor rod is inserted into the round hole to make the elastic metal sheet at the bottom contact with the metal hemisphere on the annular connecting shell, and the conductor rod and the round hole on the metal shell are glued or welded; two ends of the metal shell are connecting flanges with sealing grooves.

2 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein the electrode plate device completely wraps the outer surface of Venturi; the two electrode plate sleeves constituting the electrode plate device have the same structure; the two electrode plate sleeves are matched and connected by connecting bosses with barbs and connecting grooves arranged at two ends of the electrode plate sleeves.

3 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein the connecting shell device is cylindrical; the metal hemispheres thereon are evenly distributed in a circumferential direction, and a number of the metal hemispheres is equal to that of the electrode plates, and the metal hemispheres and the electrode plates are connected in one-to-one correspondence; the two annular connecting shells constituting the connecting shell device have the same shape; the connecting shell device is matched and fixed with a positioning boss arranged on the electrode plate device through a positioning groove arranged on the connecting shell device.

4 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein the shape of the electrode plate is the same as that of the electrode plate groove of the electrode plate sleeve, and the electrode plate grooves are arranged in multiple layers along an axial direction of the electrode plate sleeve; the number of the electrode plate grooves in each layer is the same, and the electrode plate grooves are evenly distributed along the circumferential direction; the electrode plate grooves in two adjacent layers are staggered, and an area of the outer surface of the electrode plate is larger than that of the inner surface; after being embedded in the electrode plate groove, the electrode plate sleeve is attached and fixed with the Venturi tube.

5 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein the metal hemisphere is fixed on the annular connecting shell by screws.

6 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein the electrode pate sleeve is provided with a wire slot for fixing a wire; the annular connecting shell is provided with wire holes for the wire to pass through and a wire slot for the wire to be fixed; the wire holes on the annular connecting shell are aligned with an end of the wire slot of the electrode plate sleeve; the wires passes through the wire slot on the electrode plate sleeve, then passes through the wire holes on the annular connecting shell and is welded with the metal hemisphere through the wire slot on the annular connecting shell.

7 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein a radius of the metal hemisphere is the same as a radius of the semi-cylindrical groove on the inner surface of the metal shell, and an outer diameter of the annular connecting shell is the same as an inner diameter of the metal shell.

8 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein an outer diameter of an insulating shell of the conductor rod is the same as a diameter of the round hole on the metal shell and larger than a diameter of the metal hemisphere on the annular connecting shell; the conductor rod is inserted into the round hole and then closely attached to the round hole, and the elastic metal sheet at the end of the conductor rod is in contact with the metal hemisphere on the annular connecting shell.

9 . The electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , wherein the material of the Venturi tube, the electrode pate sleeve and the annular connecting shell are insulating materials.

10 . A capacitance measurement method for an electrical capacitance volume tomography device for a cryogenic fluid flowing in a Venturi tube according to claim 1 , comprising:
keeping the metal shell grounded, and introducing a pre-cooled gaseous working medium to precool the device to prevent brittle fracture caused by quenching; during operation, firstly, using a voltage U to excite one of the electrode plates, keeping the other electrode plates at zero potential, and measuring a capacitance between the excited electrode plate and other electrode plate pairs, respectively, then using the voltage U to excite another electrode plate, measuring the capacitance between the exited electrode plate and other electrode plates at zero potential, and so on, until the capacitance measurement between all electrode plates is completed, wherein the capacitance between the combinations of every two electrode plates is measured non-repeatedly, and the recorded capacitances are used for subsequent inversion imaging.

Assignees

• Univ Zhejiang

Inventors

• Zhang Xiaobin
• Xia Tao
• Xie Huangjun

Classifications

• G01N27/221 Primary

  by investigating the dielectric properties (using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26) · CPC title

• G01N27/22

  by investigating capacitance · CPC title

• G01N27/226 Primary

  Construction of measuring vessels; Electrodes therefor · CPC title

• G01R27/2605

  Measuring capacitance (capacitive sensors G01D5/24) · CPC title

• G01N27/228

  Circuits therefor (measuring capacitance per se G01R27/26) · CPC title