Full-bore high-pressure ceramic elbow for wellhead of oil and gas field

Abstract

The invention discloses a full-bore high-pressure ceramic elbow for a wellhead of an oil and gas field, and relates to the technical field of ceramic elbows, the full-bore high-pressure ceramic elbow comprises a metal elbow and a ceramic lining pipe, two ends of the metal elbow are respectively and fixedly provided with two metal flanges with RJ ring connecting surfaces, an inner cavity is arranged in the metal elbow, the ceramic lining pipe is arranged in the inner cavity, and the RJ ring connecting surfaces are arranged in the inner cavity. A ceramic lining pipe is arranged in the inner cavity, one end of the ceramic lining pipe is connected with a buffer pipe, the buffer pipe comprises a metal pipe and a ceramic protruding section, the metal pipe is fixedly arranged in the inner cavity, the ceramic protruding section is fixedly arranged in the metal pipe in a sleeved mode, and a smooth section, an inclined section and an arc-shaped protrusion are sequentially arranged on the inner side wall of the ceramic protruding section. Through the arrangement of the buffer pipe, a flowing medium can be pre-buffered before entering the ceramic lining pipe, and the impact pressure on the ceramic lining pipe when the flowing medium flows and changes the direction is relieved, so that the impact abrasion to the ceramic lining pipe is greatly reduced, and the service life of the ceramic elbow is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic elbows, and in particular to a full-diameter high-pressure ceramic elbow for an oil and gas field wellhead. Background Art

[0002] At present, multiple elbows are arranged on the Christmas tree devices at the wellheads of oil fields and the Christmas tree devices at the wellheads of natural gas fields. Since the media of oil wells and natural gas wells contain a large amount of formation sand and the pressure is very high, the medium flow rate is very fast, and the wear of the elbows is very strong. In severe cases, the elbows will be punched through and leaked within a week, and production needs to be frequently stopped to replace or repair the elbows, which greatly affects production efficiency and poses a great safety hazard.

[0003] In order to ensure the service life of the pipeline and prevent the outer side of the elbow from being worn through by the inertia force of the flowing medium flowing through the bend of the elbow, it is often necessary to fix ceramic sheets inside the elbow to increase the wear resistance of the inner wall of the elbow. However, the current reducer elbows have insufficient connections between the internal ceramic sheets and large gaps. After long-term use, the ceramic sheets are prone to fall off under the impact of the flowing medium, thus affecting the service life of the elbow. In addition, the lengths of both ends of the elbow are usually short, and part of the impact force of the flowing medium will also act on the connection between the elbow and other pipes. Over time, the connection is prone to loosening, resulting in leakage of the flowing medium.

[0004] In view of the above problems, a full-bore high-pressure ceramic elbow for oil and gas field wellhead is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a full-diameter high-pressure ceramic elbow for oil and gas field wellheads to solve the above problems.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: A full-bore high-pressure ceramic elbow for an oil and gas field wellhead comprises a metal elbow and a ceramic lined pipe, two metal flanges with RJ ring connection surfaces are fixed at both ends of the metal elbow, an inner cavity is arranged inside the metal elbow, the ceramic lined pipe is arranged in the inner cavity, a buffer pipe is connected to one end of the ceramic lined pipe, the buffer pipe comprises a metal pipe and a ceramic protrusion section, the metal pipe is fixedly arranged inside the inner cavity, the ceramic protrusion section is fixedly sleeved inside the metal pipe, a flat section, an inclined section and an arc-shaped protrusion are arranged on the inner side wall in sequence, and flange connectors are arranged on the two metal flanges.

[0007] As a preferred solution of the present invention, the ceramic lined pipe includes a plurality of angled ceramic curved pipe sections, all of which are arranged in sequence along the inner cavity, and a first straight pipe section and a second straight pipe section are respectively arranged at both ends of the inner cavity, the first straight pipe section is located between the ceramic lined pipe and the buffer tube, and one end of the second straight pipe section is in conflict with its adjacent ceramic curved pipe section.

[0008] As a preferred solution of the present invention, the flat section is connected to the first straight pipe section, and the arc-shaped protrusion is connected to the ceramic curved pipe section.

[0009] As a preferred solution of the present invention, a ceramic connecting tube is arranged inside the metal tube, and the inner diameter of the ceramic connecting tube is the same as the inner diameter of the first straight tube section. There are multiple ceramic protrusion sections, and the multiple ceramic protrusion sections are evenly arranged inside the ceramic connecting tube along the circumferential direction.

[0010] As a preferred solution of the present invention, the flange connecting piece includes a fastening ring, a threaded ring, and a threaded connecting ring. The fastening ring is fixedly sleeved on the outside of the metal flange, the threaded ring is threadedly connected to the outer wall of the metal flange of another ceramic elbow, the threaded connecting ring is fixed on the outer wall of the threaded ring close to one end of the fastening ring, and the inner diameter of the threaded connecting ring is the same as the inner diameter of the threaded ring. The threaded connecting ring is threadedly connected to the fastening ring, and a sealing gasket is provided at the edge of the inner bottom wall of the fastening ring, and the sealing gasket is adapted to the threaded connecting ring.

[0011] As a preferred solution of the present invention, all of the metal flanges are penetrated with a plurality of through holes, and all of the through holes are evenly arranged on the inner wall of the metal flange along the circumferential direction, fastening screws are inserted into all of the through holes on one of the metal flanges, and one end of all of the fastening screws is fixedly connected to one of the metal flanges, and the other end of all of the fastening screws is threadedly connected with a nut.

[0012] As a preferred solution of the present invention, all the metal flanges are provided with mounting grooves at their extensions, and all the mounting grooves are provided with sealing rings, and the sealing rings are provided with a plurality of through holes along the circumferential direction for bolts to pass through.

[0013] As a preferred solution of the present invention, the ceramic lined pipe is cut into a plurality of ceramic curved pipe sections with an angle of α°, and the angle α° ranges from 2° to 20°.

[0014] As a preferred solution of the present invention, the length of the second straight pipe section is greater than the length of the first straight pipe section.

[0015] As a preferred solution of the present invention, both ends of the ceramic raised section are provided with raised portions, and one end of the ceramic lined pipe and one end of the first straight pipe section are provided with grooves for accommodating the raised portions.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention can improve the wear resistance of the inside of the ceramic elbow by setting a plurality of ceramic elbow sections, and prevent the turning part of the ceramic lined pipe from being worn out by the inertia when the flowing medium flows through the turning part of the ceramic lined pipe, thereby improving the service life of the ceramic elbow; 2. The present invention sets the arc-shaped protrusion of the buffer tube. When the flowing medium enters the ceramic elbow, it first passes through the first straight pipe section, then passes through the flat section, the inclined section and the arc-shaped protrusion of the inner wall of the buffer tube in sequence, and then enters the ceramic lined pipe, and then flows out from the second straight pipe section. The arc-shaped protrusion of the buffer tube can pre-buffer the flowing medium before entering the ceramic lined pipe, relieve the impact pressure on the ceramic lined pipe when the flowing medium changes direction, thereby greatly reducing the impact abrasion on the ceramic lined pipe; 3. The present invention is fixed by threaded connection of the threaded collar, the fastening collar and the threaded connection ring, which can prevent the connection part of the metal flange from loosening when the flowing medium impacts the arc-shaped protrusion of the buffer tube; the sealing performance of the threaded connection ring and the fastening collar can be improved by setting the sealing gasket, so that the two metal flanges are connected more tightly and the service life of the metal flange is extended; the cooperation of the metal flange and the flange connector makes the maintenance and replacement of the ceramic elbow more convenient, which helps to reduce the maintenance cost and time; 4. The present invention provides a plurality of ceramic protrusions evenly distributed in the center of the inner cavity of the metal elbow. When the flow medium passes through the plurality of ceramic protrusions, the flow medium can be diverted, thereby changing the flow path and speed of the flow medium, reducing local overload, and reducing the impact and abrasion of the flow medium on the ceramic lined pipe, preventing the flow medium from wearing through the turning of the ceramic lined pipe under the action of inertia when flowing through the turning of the ceramic lined pipe, thereby improving the service life of the ceramic elbow. In addition, the provision of a plurality of ceramic protrusions can reduce the residence time of the flow medium in the buffer pipe, thereby reducing the risk of blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0018] Figure 1The present invention provides a schematic diagram of the connection structure of a metal elbow and a metal flange of a full-diameter high-pressure ceramic elbow for an oil and gas field wellhead; Figure 2 A cross-sectional view of a full-diameter high-pressure ceramic elbow for an oil and gas field wellhead is provided for the present invention; Figure 3 The present invention provides a schematic diagram of the explosion structure of a full-diameter high-pressure ceramic elbow for an oil and gas field wellhead; Figure 4 The present invention provides a cross-sectional view of the internal structure of a full-diameter high-pressure ceramic elbow for an oil and gas field wellhead; Figure 5 A cross-sectional view of a buffer tube is provided for the present invention; Figure 6 A top view of a buffer tube is provided for the present invention; Figure 7 A top view of another embodiment of a buffer tube is provided for the present invention.

[0019] The numbers in the figure represent the following: 1. Metal elbow; 2. Metal flange; 3. Ceramic lined pipe; 4. Protrusion; 5. Ceramic elbow section; 6. First straight pipe section; 7. Second straight pipe section; 8. Buffer pipe; 9. Flange connector; 10. Through hole; 11. Fastening screw; 12. Nut; 13. Sealing ring; 81. Metal tube; 82. Ceramic raised section; 83. Flat section; 84. Inclined section; 85. Arc-shaped raised section; 86. Ceramic connecting tube; 91. Fastening collar; 92. Threaded collar; 93. Threaded connecting ring; 94. Sealing gasket. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0021] like Figure 1 - Figure 6As shown, the present invention provides a full-bore high-pressure ceramic elbow for oil and gas field wellheads, comprising a metal elbow 1 and a ceramic lined pipe 3, characterized in that two metal flanges 2 with RJ (Ring-Joint) ring connection surfaces are fixed at both ends of the metal elbow 1, an inner cavity is arranged inside the metal elbow 1, the ceramic lined pipe 3 is arranged in the inner cavity, one end of the ceramic lined pipe 3 is connected to a buffer tube 8, the buffer tube 8 comprises a metal tube 81 and a ceramic protrusion section 82, the metal tube 81 is fixedly arranged inside the inner cavity, the ceramic protrusion section 82 is fixedly sleeved inside the metal tube 81, a flat section 83, an inclined section 84 and an arc-shaped protrusion 85 are arranged on the inner side wall of the ceramic protrusion section 82 in sequence, and flange connectors 9 are arranged on the two metal flanges 2.

[0022] The ceramic lined tube 3 includes a plurality of angled ceramic curved tube sections 5, all of which are arranged in sequence along the inner cavity, and a first straight tube section 6 and a second straight tube section 7 are respectively arranged at both ends of the inner cavity. The first straight tube section 6 is located between the ceramic lined tube 3 and the buffer tube 8, and one end of the second straight tube section 7 is in conflict with its adjacent ceramic curved tube section 5.

[0023] Specifically, a whole ceramic liner pipe 3 is cut into several ceramic bend pipe sections 5 with angles, and all the ceramic bend pipe sections 5 are fixed to the center of the inner cavity by gluing, and the metal pipe 81 and the ceramic protrusion section 82 are sleeved and bonded to form a buffer pipe 8, and then the buffer pipe 8 is bonded to the position near the ceramic liner pipe 3 in the inner cavity, and the first straight pipe section 6 and the second straight pipe section 7 are respectively bonded to the two ends of the inner cavity, and then two metal flanges 2 with RJ ring connection surfaces are welded and fixed at both ends of the metal elbow 1. Through the setting of multiple ceramic bend pipe sections 5, the technology of setting the lining ceramic in the metal elbow 1 with the RJ ring connection surface without reducing the diameter is realized, ensuring that the inner diameter of the ceramic liner pipe 3 is consistent with the inner diameter of the metal flange 2, and by utilizing the natural wear resistance of ceramics, the service life of the metal elbow 1 is improved, which is particularly suitable for installation in the elbow position that is easily eroded and worn on the high-pressure pipeline at the wellhead of oil fields and natural gas fields. The design combining metal and ceramic materials enables the elbow to work stably under high-pressure conditions, reducing the risk of damage and leakage caused by pressure.

[0024] Among them, when the flowing medium enters the metal elbow 1, it first passes through the first straight pipe section 6, and then passes through the flat section 83, the inclined section 84 and the arc-shaped protrusion 85 of the inner wall of the buffer tube 8 in turn, and then enters the ceramic lined tube 3, and then flows out from the second straight pipe section 7. The arc-shaped protrusion 85 of the buffer tube 8 can pre-buffer the flowing medium before entering the ceramic lined tube 3, alleviate the impact pressure on the ceramic lined tube 3 caused by the flowing medium when the flow changes direction, thereby greatly reducing the impact and abrasion on the ceramic lined tube 3. Furthermore, protrusions 4 are provided at both ends of the ceramic protrusion section 82, and grooves for accommodating the protrusions 4 are provided at one end of the ceramic lined tube 3 and one end of the first straight pipe section 6.

[0025] By providing protrusions 4 at both ends of the ceramic protrusion section 82, during installation, the ceramic protrusion section 82, the ceramic liner pipe 3 and the first straight pipe section 6 are sequentially mounted and bonded to improve the stability of the ceramic protrusion section 82, thereby avoiding problems such as the ceramic protrusion section 82 falling off and loosening due to the impact pressure of the flowing medium.

[0026] In the present invention, the arrangement of multiple ceramic elbow sections 5 can improve the wear resistance of the inside of the ceramic elbow, prevent the turning of the ceramic liner tube 3 from being worn out by the inertia when the flowing medium flows through the turning of the ceramic liner tube 3, thereby improving the service life of the ceramic elbow. The design of the buffer tube 8, especially the flat section 83, the inclined section 84 and the arc-shaped protrusion 85 of the ceramic protrusion section 82, provides a buffer for the ceramic liner tube 3, reducing the damage that may be caused by direct impact contact of the flowing medium.

[0027] The flat section 83 is connected to the second straight pipe section 7, and the arc-shaped protrusion 85 is connected to the ceramic elbow section 5. This ensures that the fluid will not encounter any reduction in diameter when passing through the buffer tube 8, thereby maintaining the continuity and efficiency of the fluid flow, reducing pressure loss, keeping the full diameter inside the metal elbow 1, reducing the resistance to fluid flow, and improving the fluid delivery efficiency.

[0028] The ceramic lined pipe 3 is cut into a plurality of ceramic curved pipe sections 5 with an angle of α°, wherein the angle α° ranges from 2° to 20°, so as to optimize the fluid flow path and reduce the impact of the fluid on the ceramic lined pipe 3 .

[0029] The length of the second straight pipe section 7 is greater than that of the first straight pipe section 6 , so as to facilitate the installation of the buffer pipe 8 .

[0030] Since the buffer tube 8 is arranged near the inlet of one of the metal flanges 2, when the flowing medium impacts the buffer tube 8, the connection of the metal flange 2 at this location will be impacted and shaken. In order to improve the stability of the connection of the metal flange 2, a flange connector 9 is provided to improve the tightness and stability of the connection between the two ceramic elbows. The flange connector 9 includes a fastening ring 91, a threaded ring 92, and a threaded connection ring 93. The fastening ring 91 is fixedly sleeved on the outside of the metal flange 2. The threaded ring 92 is threadedly connected to the outer wall of the metal flange 2 of the other ceramic elbow. The threaded connection ring 93 is fixed on the outer wall of the threaded ring 92 near one end of the fastening ring 91, and the inner diameter of the threaded ring 93 is the same as the inner diameter of the threaded ring 92. The threaded connection ring 93 is threadedly connected to the fastening ring 91. A sealing gasket 94 is provided at the edge of the inner bottom wall of the fastening ring 91, and the sealing gasket 94 is adapted to the threaded connection ring 93.

[0031] All metal flanges 2 are penetrated with a plurality of through holes 10, and all through holes 10 are evenly arranged on the inner wall of the metal flange 2 along the circumferential direction, a fastening screw 11 is inserted into all the through holes 10 on one of the metal flanges 2, and one end of all the fastening screws 11 is fixedly connected to one of the metal flanges 2, and the other end of all the fastening screws 11 is threadedly connected with a nut 12.

[0032] All the metal flanges 2 are provided with mounting grooves at their outer extensions, and all the mounting grooves are provided with sealing rings 13 , and the sealing rings 13 are provided with a plurality of through holes along the circumferential direction for the bolts to pass through.

[0033] After matching the sizes of the metal flanges 2 of the two ceramic elbows to be installed and docked, unscrew the threaded collar 92 on the metal flange 2 on the first ceramic elbow in the direction away from the fastening collar 91, and then pass the sealing ring 13 through all the fastening screws 11 on the second ceramic elbow and place it in the installation groove, and insert the through hole 10 on the metal flange 2 on the first ceramic elbow into all the fastening screws 11 on the second ceramic elbow accordingly, and then rotate the threaded collar 92 to make the threaded collar 92 rotate and tighten along the outside of the metal flange 2 on the first ceramic elbow, and drive the threaded connecting ring 93 to extend into the fastening collar 91, and threadedly connect and fix it with the inner wall of the fastening collar 91 until the threaded connecting ring 93 rotates and presses against the sealing gasket 94, thereby completing the connection of the metal flanges 2 of the two ceramic elbows; further, All nuts 12 are screwed into all fastening screws 11 one by one, and the two metal flanges 2 are fixed in contact with each other to further fix the two connected metal flanges 2, thereby improving the stability of the connection between the two ceramic elbows. The threaded connection and fixation of the threaded ring 92, the fastening ring 91 and the threaded connection ring 93 can prevent the connection parts of the metal flanges 2 from loosening when the flowing medium impacts the arc-shaped protrusion 85 of the buffer tube 8; the setting of the sealing gasket 94 can improve the sealing performance of the threaded connection ring 93 and the fastening ring 91, so that the two metal flanges 2 are connected more tightly, thereby extending the service life of the metal flanges 2; the cooperation between the metal flange 2 and the flange connector 9 makes the maintenance and replacement of the ceramic elbow more convenient, which helps to reduce maintenance costs and time. Example 2

[0034] like Figure 7 As shown, on the basis of Example 1, a ceramic connecting tube 86 is arranged inside the metal tube 81, and the inner diameter of the ceramic connecting tube 86 is the same as the inner diameter of the first straight tube section 6, and a plurality of ceramic protrusion sections 82 are arranged, and the plurality of ceramic protrusion sections 82 are evenly arranged inside the ceramic connecting tube 86 along the circumferential direction.

[0035] When the flowing medium enters the ceramic elbow, the flowing medium first enters the first straight pipe section 6, then passes through the flat section 83, the inclined section 84 and the arc-shaped protrusion 85 of the inner wall of the buffer tube 8 in sequence, and then enters the ceramic lined pipe 3, and then flows out from the second straight pipe section 7. By setting a plurality of ceramic protrusion sections 82 and evenly distributing them in the ceramic connecting pipe 86, when the flowing medium passes through a plurality of ceramic protrusion sections 82, the flowing medium can be diverted, thereby changing the flow path and speed of the flowing medium, so as to reduce local overload, and reduce the impact and abrasion of the flowing medium on the ceramic lined pipe 3, and prevent the flowing medium from wearing through the turning of the ceramic lined pipe 3 under the action of inertia when flowing through the turning of the ceramic lined pipe 3, thereby improving the service life of the ceramic elbow. In addition, the setting of a plurality of ceramic protrusion sections 82 can reduce the residence time of the flowing medium in the buffer pipe 8, thereby reducing the risk of blockage.

[0036] The protection scope of the application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the application within the essence and protection scope of the application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the application.

Claims

1. A full-diameter high-pressure ceramic elbow for oil and gas field wellheads, comprising a metal elbow (1) and a ceramic lined pipe (3), characterized in that: Two metal flanges (2) having RJ ring connection surfaces are fixed to the two ends of the metal elbow (1), an inner cavity is provided inside the metal elbow (1), the ceramic lined tube (3) is provided in the inner cavity, one end of the ceramic lined tube (3) is connected to a buffer tube (8), the buffer tube (8) comprises a metal tube (81) and a ceramic raised section (82), the metal tube (81) is fixedly provided inside the inner cavity, the ceramic raised section (82) is fixedly sleeved inside the metal tube (81), a flat section (83), an inclined section (84) and an arc-shaped raised section (85) are provided on the inner side wall of the ceramic raised section (82) in sequence, and flange connectors (9) are provided on both metal flanges (2).

2. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 1, characterized in that: The ceramic lined pipe (3) comprises a plurality of ceramic curved pipe sections (5) with angles, all of which are arranged in sequence along the interior of the inner cavity, and a first straight pipe section (6) and a second straight pipe section (7) are respectively arranged at two ends of the interior of the inner cavity, the first straight pipe section (6) is located between the ceramic lined pipe (3) and the buffer pipe (8), and one end of the second straight pipe section (7) is in conflict with the adjacent ceramic curved pipe section (5).

3. A full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 2, characterized in that: The flat section (83) is connected to the first straight pipe section (6), and the arc-shaped protrusion (85) is connected to the ceramic curved pipe section (5).

4. A full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 3, characterized in that: A ceramic connecting tube (86) is arranged inside the metal tube (81), and the inner diameter of the ceramic connecting tube (86) is the same as the inner diameter of the first straight tube section (6). A plurality of ceramic protruding sections (82) are arranged, and the plurality of ceramic protruding sections (82) are evenly arranged inside the ceramic connecting tube (86) along the circumferential direction.

5. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 1, characterized in that: The flange connection piece (9) comprises a fastening collar (91), a threaded collar (92) and a threaded connection ring (93); the fastening collar (91) is fixedly sleeved on the outside of the metal flange (2); the threaded collar (92) is threadedly connected to the outer wall of the metal flange (2) of another ceramic elbow; the threaded connection ring (93) is fixed to an end of the outer wall of the threaded collar (92) close to the fastening collar (91); the inner diameter of the threaded connection ring (93) is the same as the inner diameter of the threaded collar (92); the threaded connection ring (93) is threadedly connected to the fastening collar (91); a sealing gasket (94) is provided at the edge of the inner bottom wall of the fastening collar (91); the sealing gasket (94) is adapted to the threaded connection ring (93).

6. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 1, characterized in that: All the metal flanges (2) are provided with a plurality of through holes (10), and all the through holes (10) are evenly arranged on the inner wall of the metal flange (2) along the circumferential direction, a fastening screw (11) is inserted into all the through holes (10) on one of the metal flanges (2), and one end of all the fastening screws (11) is fixedly connected to one of the metal flanges (2), and the other end of all the fastening screws (11) is threadedly connected to a nut (12).

7. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 4, characterized in that: All of the metal flanges (2) are provided with mounting grooves at their outer extensions, and all of the mounting grooves are provided with sealing rings (13), and the sealing rings (13) are provided with a plurality of through holes along the circumferential direction for bolts to pass through.

8. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 2, characterized in that: The ceramic lined pipe (3) is cut into a plurality of ceramic curved pipe sections (5) with an angle of α°, and the angle α° ranges from 2° to 20°.

9. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 2, characterized in that: The length of the second straight pipe section (7) is greater than the length of the first straight pipe section (6).

10. The full-diameter high-pressure ceramic elbow for oil and gas field wellhead according to claim 2, characterized in that: Both ends of the ceramic raised section (82) are provided with raised sections (4), and one end of the ceramic lined pipe (3) and one end of the first straight pipe section (6) are provided with grooves for accommodating the raised sections (4).

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