Piezoelectrically driven deep sea Christmas tree valve and method of operation thereof

Abstract

The application discloses a piezoelectric driving deep-sea Christmas tree valve and a working method thereof, and the valve comprises N stator assemblies, a metal upper end cover, metal pre-pressure disc springs, a plane thrust bearing, a metal switch shaft, an alumina ceramic rotor, a metal valve body, nonmetal sealing fillers, a first nonmetal sealing ring and a second nonmetal sealing ring; the application excites longitudinal vibration modes and bending modes through the stators, drives the alumina rotor to rotate by using vibration of the front end of the stator, and realizes the opening and closing states of the valve by driving the metal switch shaft to rotate; three sealing structures are arranged on the valve body and the metal switch shaft in the application, and the sealing performance of the valve is effectively improved; the valve can work in a deep-sea environment, has the advantages of high reliability, good sealing performance, long service life and the like; the valve is directly driven by the piezoelectric stator in the application, the piezoelectric stator has the advantages of simple structure, no dynamic sealing, high reliability, good pressure resistance and high repeated positioning precision; the valve can realize automatic control, and has high application value and good economic benefits in the fields of deep-sea oil and gas exploitation and the like.

Description

Technical Field

[0001] This invention relates to the fields of piezoelectric actuation and deep-sea valve technology, and in particular to a piezoelectrically actuated deep-sea wellhead valve and its operating method. Background Technology

[0002] In recent years, with the gradual depletion of onshore and shallow-sea oil and gas resources, underwater oil and gas development has become an inevitable path. Hundreds of deep-sea marine engineering projects have been put into operation worldwide, and major global oil companies are continuously increasing their investments in the deep-sea sector, leading to a rapid rise in demand for underwater oil and gas equipment. From a technological perspective, developed countries in Europe and America have achieved relatively mature technologies and possess significant advantages after decades of development. These advantages are mainly reflected in the long-term research and development experience and patented technologies held by their companies, enabling specialized division of labor in production. Currently, developed countries have deep-sea oil and gas development capabilities reaching depths of several thousand meters. Subsea production trees are key equipment for completing offshore oil and gas development operations, and various valve motors are indispensable components. Research and development of motors specifically designed for deep-sea oil valve environments has been underway for several years. Due to issues such as dynamic sealing and heat dissipation, open-type motors are gradually becoming a new development direction for deep-sea oil valve motors. Currently, most deep-sea oil valve motors use electromagnetic motors, which have complex structures, high dynamic sealing requirements, difficult heat dissipation, severe underwater performance degradation, and poor reliability.

[0003] Piezoelectric actuators are driven by the inverse piezoelectric effect, which excite high-frequency micro-amplitude vibrations of the stator through piezoelectric ceramics, thereby driving the rotor. They feature simple structure and self-locking upon power failure. Furthermore, their simple structure eliminates the need for complex underwater dynamic seals, allowing them to adapt to various extreme temperature differences and high-pressure deep-sea environments, making them the ideal actuators for deep-sea oil valves.

[0004] In existing underwater drive sources (patent publication number: CN117267403A), hydraulic components require dynamic seals and pressure compensation components, which are complex in structure, have high requirements for dynamic seals, are difficult to dissipate heat, and have poor reliability. At the same time, the repeatability of hydraulic components is low and traditional electromagnetic motors cannot achieve the function of self-locking when power is off. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of deep-sea valves in terms of motor sealing, lightweight design and valve reliability mentioned in the background art, and to provide a piezoelectrically driven deep-sea tree valve and its working method.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A piezoelectrically driven deep-sea tree valve and its operating method are characterized in that it comprises N stator assemblies, a metal upper end cap, a metal preload disc spring, a planar thrust bearing, a metal switch shaft, an alumina ceramic rotor, a metal valve body, non-metallic sealing packing, a first non-metallic sealing ring, and a second non-metallic sealing ring (N is a natural number greater than or equal to 4). The metal upper cover is a cylindrical shell structure with three evenly arranged square grooves on the side, an annular groove on the inner upper surface, and three evenly arranged semi-circular clamping ears on the bottom surface. The semi-circular clamping ears are provided with first bolt through holes. The upper end of the metal switch shaft is a disc structure, with a thin-walled ring on the outer side of the upper end face of the disc, and four circumferentially evenly arranged second threaded through holes on the upper end face of the disc; the middle part of the metal switch shaft is a cylindrical structure, with a thin-walled ring at the lower part of the cylindrical structure; the lower end of the metal switch shaft is a thin-walled spherical structure, with a cylindrical through hole on the side of the spherical structure, and the axis of the cylindrical through hole is perpendicular to the axis of the cylindrical structure in the middle part of the metal switch shaft. The alumina ceramic rotor is a disc structure with a circular through hole in the middle of the disc. The upper surface of the disc structure has four circumferentially evenly arranged second bolt through holes with the same axis as the second threaded through holes. The upper end of the metal valve body is a cylindrical disc structure. A circular through hole is provided at the center of the upper end face of the upper disc structure. Four square grooves are evenly arranged around the circumference of the upper disc. A third bolt through hole is arranged on both sides of each square groove along the radial direction. Three first threaded through holes are evenly arranged around the outer circumference of the upper disc. An annular groove is provided on the inner side of the upper cylindrical structure. The middle part of the metal valve body is a spherical thin-walled structure. The two sides of the metal valve body are cylindrical disc structures, and a cylindrical through hole is provided at the center of the cylindrical disc structure. The stator assembly includes an alumina ceramic friction head, a metal stator substrate, and a piezoelectric ceramic assembly. The non-metallic friction head has a semi-cylindrical structure and is made of alumina ceramic. The metal stator substrate has a square beam structure with a gradually decreasing cross-section at the front end. The front end of the metal stator substrate is bonded to the non-metallic friction head with epoxy resin adhesive. Square clamping ears are provided on both sides of the middle of the square beam, and a third threaded through hole is provided on the upper end face of the clamping ears. The piezoelectric ceramic assembly has a square plate structure and includes 2A piezoelectric ceramic assemblies. The first A piezoelectric ceramic plates are the first piezoelectric ceramic assemblies, and the last A piezoelectric ceramic plates are the second piezoelectric ceramic assemblies. A is a natural number greater than or equal to 1. All ceramic plates are single-section ceramic plates, and all ceramic plates have the same polarization direction. The ceramic plates are bonded to the metal stator substrate with epoxy resin adhesive. The stator assembly is circumferentially arranged in a square slot in the metal valve body, and is fixed by bolts connecting the third bolt through hole and the third threaded through hole; the alumina ceramic rotor and the metal switch shaft are fixed by bolts, the second bolt through hole and the second threaded through hole; the metal upper end cover and the metal valve body are fixed by bolts, the first bolt through hole and the first threaded through hole. The planar thrust bearing and the metal switch shaft are assembled by an interference fit. The preload is pressed against the metal preload disc spring by the metal upper end cover. The force generated by the deformation of the preload disc spring is transmitted to the metal switch shaft through the planar thrust bearing, and finally the metal switch shaft is transmitted to the stator assembly. The metal switch shaft and the metal valve body press against the first non-metallic sealing ring to form a first seal, the metal switch shaft and the metal valve body press against the second non-metallic sealing ring to form a second seal, and the metal switch shaft and the metal valve body press against the third non-metallic sealing ring to form a third seal. The piezoelectric drive stator is composed of N stators connected in parallel, and the entire drive unit is used in an underwater working environment; The surfaces of the piezoelectric ceramic sheet that come into contact with seawater are all provided with an insulating coating; The metal switch shaft and the first non-metallic sealing ring are in a transition fit, and the friction coefficient of the first non-metallic sealing ring material is low, which has a low impact on the operation of the metal switch shaft. The metal switch shaft and the second non-metallic sealing ring are in transition fit, and the friction coefficient of the second non-metallic sealing ring and the non-metallic sealing packing is low, which has a low impact on the operation of the metal switch shaft. The materials of all non-metallic sealing rings are high-performance elastomer rubber, high-performance engineering plastics, or composite materials, etc. This invention also discloses a piezoelectrically driven deep-sea production tree valve and its operating method, comprising the following steps: Regarding the driving principle of the piezoelectric stator assembly, a first AC signal is applied to A ceramic plates of the first piezoelectric ceramic group of the stator assembly, and a second AC signal is applied to A ceramic plates of the second piezoelectric ceramic group of the stator assembly. The first and second AC signals have a time phase difference of 90° or -90°, which simultaneously excites the first-order longitudinal vibration mode and the second-order bending vibration mode of the two spatially orthogonal ends of the piezoelectric driven stator, causing the particles on the friction head to perform elliptical motion. Through friction, the rotor is driven to rotate. When the same electrical signal is applied to N stators, the N stators drive the rotor to rotate together. The rotor drives the metal switch shaft to rotate, thereby realizing the opening and closing state of the valve. In terms of sealing and pressure resistance, this invention does not require dynamic sealing of the stator-rotor contact parts of the drive component. It only needs to ensure that the piezoelectric ceramic plates in the piezoelectric drive stator are insulated from seawater. The sealing requirements are extremely low, and it can adapt to marine environments at different depths. Compared with traditional motors, which suffer from increased difficulty in dynamic sealing, motor performance degradation, and heat dissipation difficulties in the high water pressure environment of the deep sea, this invention does not require dynamic sealing and has an integrated structural design. The stator directly drives the valve switching shaft, avoiding transmission errors, achieving high repeatability, good pressure resistance, and good mechanical output performance.

[0007] Compared with existing technical solutions, the present invention, employing the above technical solution, has the following technical advantages: 1. The piezoelectric drive stator of the present invention can directly drive the metal switch shaft without the need for a transmission mechanism and complex components, thus avoiding transmission errors, improving driving accuracy, and realizing an integrated functional design; moreover, the drive part is low in cost, small in size, simple in structure, and highly reliable.

[0008] 2. In this invention, there is no need to perform dynamic sealing on the stator and rotor contact parts of the drive source. It is only necessary to ensure that the piezoelectric ceramic plates and electrode plates in the piezoelectric drive stator are insulated from seawater. The sealing requirements are extremely low, and it can adapt to marine environments at different depths. Compared with the defects of traditional motors in the deep-sea high water pressure environment, such as increased difficulty in dynamic sealing, motor performance degradation and heat dissipation difficulties, this invention does not require dynamic sealing, but has good pressure resistance and good mechanical output performance.

[0009] 3. The invention employs three sealing measures, which greatly reduces the possibility of valve leakage and effectively ensures the possibility of long-term valve operation.

[0010] 4. In this invention, the valve is driven by a piezoelectric servo drive source, which has high repeatability and positioning accuracy, ensuring long-term effective operation of the valve. Attached Figure Description

[0011] Figure 1 This is a schematic cross-sectional view of the valve structure in this invention; Figure 2 This is a schematic diagram of the overall structure of the valve in this invention; Figure 3 This is a schematic diagram of the valve explosion in this invention; Figure 4 This is a schematic diagram of the valve body seal in this invention; Figure 5 This is a schematic diagram of the multi-stator drive principle of the valve body in this invention. Figure 6 (a) and (b) are the valve opening and closing working states of the valve structure switch shaft rotating around the Z-axis in this invention; Figure 7 This is an exploded view of the stator assembly in this invention; Figure 8 This is a schematic diagram of the electrical signal excitation method of the piezoelectric component in this invention; Figure 9 This is a schematic diagram illustrating the working principle of the stator assembly in this invention; In the diagram, 1-metal upper end cover, 2-planar thrust bearing, 3-stator assembly, 4-second non-metallic sealing ring, 5-metal valve body, 6-first non-metallic sealing ring, 7-metal switch shaft, 8-non-metallic packing, 9-alumina ceramic rotor, 10-metal preload disc spring, 11-alumina ceramic friction head, 12-metal stator base, 13.1-single-section piezoelectric ceramic, 13.2-single-section piezoelectric ceramic, 13.3-single-section piezoelectric ceramic, 13.4-single-section piezoelectric ceramic Detailed Implementation

[0012] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings: This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0013] like Figure 1 , 2 As shown in Figure 3, this invention discloses a piezoelectrically driven deep-sea tree valve and its operating method, characterized in that it comprises N stator assemblies, a metal upper end cover, a metal preload disc spring, a planar thrust bearing, a metal switch shaft, an alumina ceramic rotor, a metal valve body, non-metallic sealing packing, a first non-metallic sealing ring, and a second non-metallic sealing ring (N is a natural number greater than or equal to 4). The metal upper cover is a cylindrical shell structure with three evenly arranged square grooves on the side, an annular groove on the inner upper surface, and three evenly arranged semi-circular clamping ears on the bottom surface. The semi-circular clamping ears are provided with first bolt through holes. The upper end of the metal switch shaft is a disc structure, with a thin-walled ring on the outer side of the upper end face of the disc, and four circumferentially evenly arranged second threaded through holes on the upper end face of the disc; the middle part of the metal switch shaft is a cylindrical structure, with a thin-walled ring at the lower part of the cylindrical structure; the lower end of the metal switch shaft is a thin-walled spherical structure, with a cylindrical through hole on the side of the spherical structure, and the axis of the cylindrical through hole is perpendicular to the axis of the cylindrical structure in the middle part of the metal switch shaft. The alumina ceramic rotor is a disc structure with a circular through hole in the middle of the disc. The upper surface of the disc structure has four circumferentially evenly arranged second bolt through holes with the same axis as the second threaded through holes. The upper end of the metal valve body is a cylindrical disc structure. A circular through hole is provided at the center of the upper end face of the upper disc structure. Four square grooves are evenly arranged around the circumference of the upper disc. A third bolt through hole is arranged on both sides of each square groove along the radial direction. Three first threaded through holes are evenly arranged around the outer circumference of the upper disc. An annular groove is provided on the inner side of the upper cylindrical structure. The middle part of the metal valve body is a spherical thin-walled structure. The two sides of the metal valve body are cylindrical disc structures, and a cylindrical through hole is provided at the center of the cylindrical disc structure. like Figure 7 As shown, the stator assembly includes an alumina ceramic friction head, a metal stator substrate, and a piezoelectric ceramic assembly. The non-metallic friction head has a semi-cylindrical structure and is made of alumina ceramic. The metal stator substrate has a square beam structure with a gradually decreasing cross-section at the front end. The front end of the metal stator substrate is bonded to the non-metallic friction head with epoxy resin adhesive. Square clamping ears are provided on both sides of the middle of the square beam, and a third threaded through hole is provided on the upper end face of the clamping ears. The piezoelectric ceramic assembly has a square plate structure and includes 2A piezoelectric ceramic assemblies. The first A piezoelectric ceramic plates are the first piezoelectric ceramic assemblies, and the last A piezoelectric ceramic plates are the second piezoelectric ceramic assemblies. A is a natural number greater than or equal to 1. All ceramic plates are single-section ceramic plates, and all ceramic plates have the same polarization direction. The ceramic plates are bonded to the metal stator substrate with epoxy resin adhesive. The stator assembly is circumferentially arranged in a square slot in the metal valve body, and is fixed by bolts connecting the third bolt through hole and the third threaded through hole; the alumina ceramic rotor and the metal switch shaft are fixed by bolts, the second bolt through hole and the second threaded through hole; the metal upper end cover and the metal valve body are fixed by bolts, the first bolt through hole and the first threaded through hole. The planar thrust bearing and the metal switch shaft are assembled by an interference fit. The preload is pressed against the metal preload disc spring by the metal upper end cover. The force generated by the deformation of the preload disc spring is transmitted to the metal switch shaft through the planar thrust bearing, and finally the metal switch shaft is transmitted to the stator assembly. like Figure 4 As shown, the metal switch shaft and the metal valve body compress the first non-metallic sealing ring to form a first seal, the metal switch shaft and the metal valve body compress the second non-metallic sealing ring to form a second seal, and the metal switch shaft and the metal valve body compress the third non-metallic sealing ring to form a third seal. The piezoelectric drive stator is composed of N stators connected in parallel, and the entire drive unit is used in an underwater working environment; The surfaces of the piezoelectric ceramic sheet that come into contact with seawater are all provided with an insulating coating; The metal switch shaft and the first non-metallic sealing ring are in a transition fit, and the friction coefficient of the first non-metallic sealing ring material is low, which has a low impact on the operation of the metal switch shaft. The metal switch shaft and the second non-metallic sealing ring are in transition fit, and the friction coefficient of the second non-metallic sealing ring and the non-metallic sealing packing is low, which has a low impact on the operation of the metal switch shaft. The materials of all non-metallic sealing rings are high-performance elastomer rubber, high-performance engineering plastics, or composite materials, etc. like Figure 5 , 6 As shown in Figures 8 and 9, this invention also discloses a piezoelectrically driven deep-sea production tree valve and its operating method, comprising the following steps: Regarding the driving principle of the piezoelectric stator assembly, a first AC signal is applied to A ceramic plates of the first piezoelectric ceramic group of the stator assembly, and a second AC signal is applied to A ceramic plates of the second piezoelectric ceramic group of the stator assembly. The first and second AC signals have a time phase difference of 90° or -90°, which simultaneously excites the first-order longitudinal vibration mode and the second-order bending vibration mode of the two spatially orthogonal ends of the piezoelectric driven stator, causing the particles on the friction head to perform elliptical motion. Through friction, the rotor is driven to rotate. When the same electrical signal is applied to N stators, the N stators drive the rotor to rotate together. The rotor drives the metal switch shaft to rotate, thereby realizing the opening and closing state of the valve. In terms of sealing and pressure resistance, this invention does not require dynamic sealing of the stator-rotor contact parts of the drive component. It only needs to ensure that the piezoelectric ceramic plates in the piezoelectric drive stator are insulated from seawater. The sealing requirements are extremely low, and it can adapt to marine environments at different depths. Compared with traditional motors, which suffer from increased difficulty in dynamic sealing, motor performance degradation, and heat dissipation difficulties in the high water pressure environment of the deep sea, this invention does not require dynamic sealing and has an integrated structural design. The stator directly drives the valve switching shaft, avoiding transmission errors, achieving high repeatability, good pressure resistance, and good mechanical output performance.

Claims

1. A piezoelectrically driven deep-sea production tree valve and its operating method, characterized in that, It includes N stator assemblies, a metal upper end cover, a metal preload disc spring, a planar thrust bearing, a metal switch shaft, an alumina ceramic rotor, a metal valve body, non-metallic sealing packing, a first non-metallic sealing ring, and a second non-metallic sealing ring (N is a natural number greater than or equal to 4). The metal upper cover is a cylindrical shell structure with three evenly arranged square grooves on the side, an annular groove on the inner upper surface, and three evenly arranged semi-circular clamping ears on the bottom surface. The semi-circular clamping ears are provided with first bolt through holes. The upper end of the metal switch shaft is a disc structure, with a thin-walled ring on the outer side of the upper end face of the disc, and four circumferentially evenly arranged second threaded through holes on the upper end face of the disc; the middle part of the metal switch shaft is a cylindrical structure, with a thin-walled ring at the lower part of the cylindrical structure; the lower end of the metal switch shaft is a thin-walled spherical structure, with a cylindrical through hole on the side of the spherical structure, and the axis of the cylindrical through hole is perpendicular to the axis of the cylindrical structure in the middle part of the metal switch shaft. The alumina ceramic rotor is a disc structure with a circular through hole in the middle of the disc. The upper surface of the disc structure has four circumferentially evenly arranged second bolt through holes with the same axis as the second threaded through holes. The upper end of the metal valve body is a cylindrical disc structure. A circular through hole is provided at the center of the upper end face of the upper disc structure. Four square grooves are evenly arranged around the circumference of the upper disc. A third bolt through hole is arranged on both sides of each square groove along the radial direction. Three first threaded through holes are evenly arranged around the outer circumference of the upper disc. An annular groove is provided on the inner side of the upper cylindrical structure. The middle part of the metal valve body is a spherical thin-walled structure. The two sides of the metal valve body are cylindrical disc structures, and a cylindrical through hole is provided at the center of the cylindrical disc structure. The stator assembly includes an alumina ceramic friction head, a metal stator substrate, and a piezoelectric ceramic assembly. The non-metallic friction head has a semi-cylindrical structure and is made of alumina ceramic. The metal stator substrate has a square beam structure with a gradually decreasing cross-section at the front end. The front end of the metal stator substrate is bonded to the non-metallic friction head with epoxy resin adhesive. Square clamping ears are provided on both sides of the middle of the square beam, and a third threaded through hole is provided on the upper end face of the clamping ears. The piezoelectric ceramic assembly has a square plate structure and includes 2A piezoelectric ceramic assemblies. The first A piezoelectric ceramic plates are the first piezoelectric ceramic assemblies, and the last A piezoelectric ceramic plates are the second piezoelectric ceramic assemblies. A is a natural number greater than or equal to 1. All ceramic plates are single-section ceramic plates, and all ceramic plates have the same polarization direction. The ceramic plates are bonded to the metal stator substrate with epoxy resin adhesive. The stator assembly is circumferentially arranged in a square slot in the metal valve body, and is fixed by bolts connecting the third bolt through hole and the third threaded through hole; the alumina ceramic rotor and the metal switch shaft are fixed by bolts, the second bolt through hole and the second threaded through hole; the metal upper end cover and the metal valve body are fixed by bolts, the first bolt through hole and the first threaded through hole. The planar thrust bearing and the metal switch shaft are assembled by an interference fit. The preload is pressed against the metal preload disc spring by the metal upper end cover. The force generated by the deformation of the preload disc spring is transmitted to the metal switch shaft through the planar thrust bearing, and finally the metal switch shaft is transmitted to the stator assembly. The metal switch shaft and the metal valve body compress the first non-metallic sealing ring to form a first seal, the metal switch shaft and the metal valve body compress the second non-metallic sealing ring to form a second seal, and the metal switch shaft and the metal valve body compress the third non-metallic sealing ring to form a third seal.

2. The piezoelectrically driven deep-sea wellhead valve according to claim 1, characterized in that, The piezoelectric drive stator is composed of N stators connected in parallel, and the entire drive unit is used in underwater working environments.

3. The piezoelectrically driven deep-sea wellhead valve according to claim 1, characterized in that... The surfaces of the piezoelectric ceramic sheet that come into contact with seawater are all provided with an insulating coating.

4. The piezoelectrically driven deep-sea wellhead valve according to claim 1, characterized in that... The metal switch shaft and the first non-metallic sealing ring are in a transition fit, and the friction coefficient of the first non-metallic sealing ring material is low, which has a low impact on the operation of the metal switch shaft.

5. A piezoelectrically driven deep-sea production tree valve according to claim 1, characterized in that... The metal switch shaft and the second non-metallic sealing ring are in a transition fit, and the friction coefficient of the second non-metallic sealing ring and the non-metallic sealing packing is low, which has a low impact on the operation of the metal switch shaft.

6. The piezoelectrically driven deep-sea production tree valve according to claim 1, characterized in that... All non-metallic sealing rings are made of high-performance elastomer rubber, high-performance engineering plastics, or composite materials.

7. The working method of a piezoelectrically driven deep-sea wellhead valve according to claim 1, characterized in that... Includes the following points: Regarding the driving principle of the piezoelectric stator assembly, a first AC signal is applied to A ceramic plates of the first piezoelectric ceramic group of the stator assembly, and a second AC signal is applied to A ceramic plates of the second piezoelectric ceramic group of the stator assembly. The first and second AC signals have a time phase difference of 90° or -90°, which simultaneously excites the first-order longitudinal vibration mode and the second-order bending vibration mode of the two spatially orthogonal ends of the piezoelectric driven stator, causing the particles on the friction head to perform elliptical motion. Through friction, the rotor is driven to rotate. When the same electrical signal is applied to N stators, the N stators drive the rotor to rotate together. The rotor drives the metal switch shaft to rotate, thereby realizing the opening and closing state of the valve. In terms of sealing and pressure resistance, this invention does not require dynamic sealing of the stator-rotor contact parts of the drive component. It only needs to ensure that the piezoelectric ceramic plates in the piezoelectric drive stator are insulated from seawater. The sealing requirements are extremely low, and it can adapt to marine environments at different depths. Compared with traditional motors, which suffer from increased difficulty in dynamic sealing, motor performance degradation, and heat dissipation difficulties in the high water pressure environment of the deep sea, this invention does not require dynamic sealing and has an integrated structural design. The stator directly drives the valve switching shaft, avoiding transmission errors, achieving high repeatability, good pressure resistance, and good mechanical output performance.

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