Pressure follow-up type rotary blowout preventer

Abstract

The utility model discloses a pressure follow-up type rotary blowout preventer, and belongs to the field of petroleum equipment. The utility model comprises: a housing; the rotating assembly comprises a fixing sleeve and a rotating head, an upper movable sealing ring is installed on the inner wall of the upper end of the fixing sleeve, a lower movable sealing ring is installed on the inner wall of the lower end of the fixing sleeve, the rotating head is rotationally installed in the fixing sleeve, and a sealing cavity is formed between the outer wall of the rotating head and the upper movable sealing ring and the lower movable sealing ring; an oil outlet communicated with the sealing cavity is formed in the upper part of the fixing sleeve, and an oil inlet communicated with the sealing cavity is formed in the lower part; and a follow-up valve. The follow-up valve can automatically adjust the pressure of hydraulic oil in the oil outlet pipe, under the certain pressure effect of mud in a well, acting force generated by oil pressure needs to overcome acting force generated by the mud in the well and reverse thrust generated by the spring, and therefore the oil pressure is slightly higher than the well pressure at the moment; therefore, the pressure of hydraulic oil in the sealing cavity is larger than the well pressure below the lower movable sealing ring, and mud media in a well can be effectively prevented from invading the lower movable sealing ring to affect the service life of the lower movable sealing ring.

Description

TECHNICAL FIELD

[0001] The utility model relates to petroleum equipment technical field more specifically relates to a pressure follow-up type rotary blowout preventer. BACKGROUND

[0002] Rotary blowout preventer is used more and more widely in modern drilling, is the key equipment in pressure control drilling and underbalanced drilling, with the continuous improvement of drilling depth and drilling speed, higher requirements are put forward to the performance of rotary blowout preventer, and the dynamic sealing ring of rotary blowout preventer works under high pressure and high speed, and the working condition is very bad, especially the lower dynamic sealing ring, because its lower part directly contacts with the mud containing abrasive particles, the mud is easy to invade the dynamic sealing part during work, causing the abrasion to aggravate, and the sealing is rapidly invalid, and the sealing failure will cause the mud to invade the inside of rotary control head, causing serious damage to bearings and other moving parts.

[0003] Therefore, how to provide a pressure follow-up type rotary blowout preventer with good sealing performance and bearings and other remote moving parts not easy to damage is a problem to be solved by those skilled in the art. SUMMARY

[0004] Therefore, the utility model aims at providing a pressure follow-up type rotary blowout preventer to at least solve the technical problem that the sealing structure is easy to damage in the prior art, causing the mud to invade the inside of rotary control head, causing damage to bearings and other moving parts.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A pressure follow-up type rotary blowout preventer, comprising:

[0007] A housing, a central hole is formed in the top of the housing, and a mud outlet is formed in the side wall of the housing;

[0008] A rotary assembly, the rotary assembly comprises a fixed sleeve and a rotary head, the fixed sleeve is connected in the central hole, an upper dynamic sealing ring is installed on the inner wall of the upper end of the fixed sleeve, a lower dynamic sealing ring is installed on the inner wall of the lower end of the fixed sleeve, the rotary head is rotatably installed in the fixed sleeve, and the outer wall of the rotary head forms a sealed cavity with the upper dynamic sealing ring and the lower dynamic sealing ring, and a bearing is installed on the side wall of the rotary head corresponding to the sealed cavity; An oil outlet hole is formed in the upper part of the fixed sleeve and communicates with the sealed cavity, an oil inlet hole is formed in the lower part of the fixed sleeve and communicates with the sealed cavity, and the oil inlet hole is connected with the hydraulic control equipment through an oil inlet pipe;

[0009] The follow-up valve comprises a valve body, a valve core, a limiting ring and a spring, the valve body is in a closed barrel type structure, one end of the valve body is fixed on the outer wall of the shell, and an oil hole is formed in the end of the valve body and communicated with the mud outlet; an oil inlet hole is formed in the side wall of the valve body corresponding to the inner cavity of the valve body and communicated with the inner cavity of the valve body, and an oil return hole is formed in the side wall of the valve body corresponding to the oil hole and communicated with the oil hole; the oil inlet hole is communicated with the oil hole through an oil outlet pipe; one end of the valve core is slidably connected in the oil hole in the axial direction of the oil hole, the other end of the valve core extends into the inner cavity of the valve body, and a valve core oil hole is formed in the end of the other end of the valve core, the valve core oil hole is a blind hole; the side wall of the valve core is provided with an oil inlet channel communicated with the valve core oil hole and the inner cavity of the valve body corresponding to the inner cavity of the valve body, and a throttle hole communicated with the valve core oil hole and the oil return hole is formed in the side wall of the valve core corresponding to the oil hole; the limiting ring is fixed on the other end of the valve core and the outer ring wall of the limiting ring is slidably connected with the inner side wall of the valve body, and the spring is sleeved on the valve core between the limiting ring and the inner wall of the valve body close to the end of the shell.

[0010] The follow-up valve can automatically adjust the pressure of hydraulic oil in the oil outlet pipe under the action of mud pressure and spring expansion and contraction, under the action of mud with a certain pressure in the well, the force generated by oil pressure needs to overcome the force generated by mud in the well and the counter thrust generated by the spring, so the oil pressure at this time will be slightly higher than the well pressure, so that the hydraulic oil pressure in the sealing cavity is greater than the mud pressure below the lower dynamic sealing ring in the well, thereby effectively preventing the mud medium in the well from invading the lower dynamic sealing ring and affecting the service life of the lower dynamic sealing ring.

[0011] Preferably, the valve body comprises a valve cover, a valve shell and a valve sleeve, the valve cover is fixed on the side wall of the shell, the valve cover is provided with a mud inlet hole communicated with the mud outlet hole, the valve shell is in a closed barrel type structure, and the open end of the valve shell is fixed on the valve cover, the inner cavity of the valve shell comprises a valve sleeve mounting hole and a valve core mounting hole coaxially arranged from the open end to the closed end and communicated with each other, the diameter of the valve cover mounting hole is greater than the diameter of the valve core mounting hole so that a shoulder is formed at the connection position, the oil inlet hole is formed in the valve shell corresponding to the valve core mounting hole and communicated with the valve core mounting hole, and the oil return hole is formed in the valve shell corresponding to the valve sleeve mounting hole and communicated with the valve sleeve mounting hole; the valve sleeve is mounted in the valve sleeve mounting hole, one end of the valve sleeve abuts against the shoulder of the valve cover, and the other end of the valve sleeve abuts against the valve cover, the inner cavity of the valve sleeve is the oil hole and the oil hole is communicated with the mud inlet hole, the inner wall of the valve sleeve is provided with an annular groove corresponding to the oil return hole, the bottom of the annular groove is provided with an oil return channel communicated with the oil return hole corresponding to the oil return hole, and the other end of the spring abuts against the end face of the valve sleeve away from the end of the shell.

[0012] The diameter of the mud inlet hole gradually decreases away from the shell.

[0013] The oil inlet channel is provided on the valve shell side wall, and the oil inlet end of the oil inlet channel is connected with the hydraulic control device, and the oil outlet end is communicated with the oil inlet pipe.

[0014] The connection between the valve cover and the mud outlet, the connection between the valve cover and the valve shell, the connection between the valve shell and the valve sleeve, and the connection between the valve sleeve and the valve cover are all provided with sealing rings.

[0015] The end face of the limiting ring away from one end of the shell is a bevel, and the diameter of the bevel gradually decreases away from the shell.

[0016] Compared with the prior art, the utility model discloses a pressure follow-up type rotary blowout preventer, through the automatic control effect of the follow-up valve, the pressure in the sealing cavity is changed, the oil pressure inside the sealing cavity is always higher than well pressure, and can automatically change along with the change of well pressure, can effectively prevent the mud medium in the well from invading the rotary sealing position and affecting the service life, through the above-mentioned measures, the dynamic sealing working condition of the rotary head can be greatly improved with lower cost, and therefore the overall service life is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are only the embodiments of the utility model, and for the ordinary skilled in the art, other drawings can be obtained according to the provided drawings without the creative labor.

[0018] Figure 1 The utility model provides a pressure follow-up type rotary blowout preventer structure schematic diagram.

[0019] Figure 2 The utility model provides a pressure follow-up type rotary blowout preventer left view cross section structure schematic diagram.

[0020] Figure 3 The utility model provides a pressure follow-up type rotary blowout preventer main view cross section structure schematic diagram.

[0021] Figure 4 The utility model provides follow-up valve initial state main view cross section structure schematic diagram.

[0022] Figure 5 The utility model provides follow-up valve working state main view cross section structure schematic diagram.

[0023] Figure 6 The utility model provides follow-up valve left view cross section structure schematic diagram.

[0024] Figure 7 The utility model provides a servo valve explosion structure schematic diagram.

[0025] In the drawing: 1, shell, 11, mud outlet;

[0026] 2, rotation assembly, 21, fixed cover, 22, rotation head, 23, upper dynamic seal ring, 24, lower dynamic seal ring, 25, seal cavity, 26, bearing, 27, oil outlet hole, 28, oil inlet hole,

[0027] 3, oil inlet pipe,

[0028] 4, servo valve, 41, valve body, 411, valve cover, 4111, mud inlet, 412, valve shell, 4121, oil inlet, 4122, oil return port, 4123, valve sleeve mounting hole, 4124, valve core mounting hole, 4125, oil delivery channel, 4126, annular oil cavity, 413, valve sleeve, 4131, sliding hole, 4132, annular groove, 4133, oil return channel, 42, valve core, 421, valve core oil hole, 422, oil inlet channel, 423, throttle hole, 43, limit ring, 44, spring,

[0029] 5, oil outlet pipe;

[0030] 6, seal ring;

[0031] 7, oil return pipe;

[0032] 8, oil delivery pipe;

[0033] 9, clamp. DETAILED DESCRIPTION

[0034] The technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the protection scope of the utility model.

[0035] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the utility model.

[0036] In the utility model, unless another definite provision and limitation, the terms "mount", "link", "connect", "fix" and so on terms should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be direct connection, also can pass through intermediate medium indirectly connect, can be two element inside's intercommunication or two element's interaction relationship.For ordinary skilled person in the art, can understand the concrete meaning of above-mentioned term in the utility model according to specific circumstances.

[0037] Please refer to Figures 1-7 The utility model discloses a pressure follow-up type rotary blowout preventer, including:

[0038] Shell 1, shell 1 top is provided with central hole, and the lateral wall is provided with slurry outlet 11;

[0039] Rotary assembly 2, rotary assembly 2 includes fixed sleeve 21 and rotary head 22, and fixed sleeve 21 is connected in central hole and is fixed through clamp 9, and the upper end inner wall of fixed sleeve 21 is installed with upper dynamic sealing ring 23, and the lower end inner wall is installed with lower dynamic sealing ring 24, and rotary head 22 is rotatably installed in fixed sleeve 21, and its outer wall forms sealed cavity 25 between upper dynamic sealing ring 23 and lower dynamic sealing ring 24, and the lateral wall of rotary head 22 is installed with bearing 26 corresponding sealed cavity 25;Fixed sleeve 21 upper part is provided with the oil outlet hole 27 of the communication sealed cavity 25, and lower part is provided with the oil inlet hole 28 of the communication sealed cavity 25, and the oil inlet hole 28 is communicated with hydraulic control equipment through oil inlet pipe 3;

[0040] Follow-up valve 4, follow-up valve 4 includes valve body 41, valve core 42, limit ring 43 and spring 44, and valve body 41 is the barrel type structure of closed two ends, and one end is fixed on the outer wall of shell 1, and the end of one end is provided with sliding hole 4131 communicated with slurry outlet 11;Valve body 41 lateral wall is provided with oil inlet 4121 communicated with its inner cavity corresponding its inner cavity, and is provided with oil return 4122 communicated with sliding hole 4131 corresponding sliding hole 4131, and oil inlet 4121 is communicated with oil outlet hole 27 through oil outlet pipe 5;Valve core 42 one end is slidably connected in sliding hole 4131 along the axial direction of sliding hole 4131, and the other end extends to the inner cavity of valve body 41, and the other end end is provided with valve core oil hole 421, and valve core oil hole 421 is blind hole, and the lateral wall of valve core 42 is provided with oil inlet passage 422 communicated with valve core oil hole 421 and the inner cavity of valve body 41 corresponding the inner cavity of valve body 41, and is provided with throttle hole 423 communicated with valve core oil hole 421 and oil return 4122 corresponding sliding hole 4131;Limit ring 43 is fixed on the other end of valve core 42 and the outer ring wall thereof is slidably connected with the inner side wall of valve body 41, and spring 44 is sleeved on valve core 42 between limit ring 43 and the inner wall of valve body 41 close to the one end of shell 1.

[0041] The beneficial effects realized by the utility model: the valve core 42 of the follow-up valve 4 can automatically adjust the pressure of the hydraulic oil in the oil pipe 5 under the mud pressure and the spring 44 extension and retraction, under the action of the mud in the well with a certain pressure, the force generated by the oil pressure needs to overcome the force generated by the mud in the well, and also needs to overcome the counter thrust generated by the spring 44, so the oil pressure at this time will be slightly higher than the well pressure, thereby the pressure in the sealing cavity 25 is greater than the mud pressure in the well below the lower dynamic sealing ring 24, thereby the mud medium in the well can be effectively prevented from invading the lower dynamic sealing ring 24, and the service life is affected.

[0042] In a specific embodiment, the valve body 41 comprises a valve cover 411, a valve shell 412 and a valve sleeve 413, the valve cover 411 is fixed on the side wall of the shell 1, the mud inlet 4111 communicating with the mud outlet 11 is formed in the valve cover 411, the valve shell 412 is in a cylindrical structure with one end closed, and the open end thereof is fixed on the valve cover 411, the inner cavity of the valve shell 412 comprises a valve sleeve mounting hole 4123 and a valve core mounting hole 4124 coaxially arranged from the open end to the closed end and communicating with each other, the mounting hole diameter of the valve cover 411 is greater than the valve core mounting hole 4124 so as to form a shoulder at the connection part, the oil inlet 4121 is formed at the position corresponding to the valve core mounting hole 4124 of the valve shell 412 and communicates with the valve core mounting hole 4124, and the oil return port 4122 is formed at the position corresponding to the valve sleeve mounting hole 4123 of the valve shell 412 and communicates with the valve sleeve mounting hole 4123; the valve sleeve 413 is mounted in the valve sleeve mounting hole 4123, and one end abuts against the shoulder of the valve cover 411, and the other end abuts against the valve cover 411, the inner cavity of the valve sleeve 413 is a sliding hole 4131, the sliding hole 4131 communicates with the mud inlet 4111, the annular groove 4132 is formed in the inner wall of the valve sleeve 413 corresponding to the oil return port 4122, the oil return channel 4133 communicating with the oil return port 4122 is formed in the groove bottom of the annular groove 4132 corresponding to the oil return port 4122, and the other end of the spring 44 abuts against the end face of the valve sleeve 413 away from the shell 1.

[0043] In a specific embodiment, the valve cover 411 comprises an integrally connected first plug-in part, a second plug-in part and a mounting flange, one end of the first plug-in part is plugged into the mud outlet; the valve sleeve mounting hole 4123 of the valve shell 412 is provided with an annular valve cover mounting groove arranged through the end face close to the shell 1; one end of the second plug-in part is connected to the other end of the first plug-in part, and the other end is plugged into the annular valve cover mounting groove, and an annular oil cavity 4126 is formed between the end face of the second plug-in part and the groove wall of the annular mounting groove, the annular oil cavity 4126 communicates with the oil return port 412 and the oil return channel 4133; the mounting flange is fixed on the outer side wall of the first plug-in part, is mounted on the side wall of the shell 1 by bolts, and is connected with the valve shell 412 by bolts.

[0044] The diameter of the mud inlet 4111 gradually decreases away from the shell 1. It is convenient for the mud to enter to push the valve core 42 to move.

[0045] The oil inlet channel 422 is formed in the side wall of the valve housing 412, and the oil inlet end of the oil inlet channel 422 is connected with the hydraulic control device, and the oil outlet end is communicated with the oil inlet pipe 3. The oil inlet pipe 3 is fixed to prevent the oil inlet pipe 3 from falling off.

[0046] The sealing ring 6 is arranged at the connection between the valve cover 411 and the mud outlet 11, the connection between the valve cover 411 and the valve housing 412, the connection between the valve housing 412 and the valve sleeve 413, and the connection between the valve sleeve 413 and the valve cover 411. The sealing ring 6 seals the connection between the valve cover 411 and the valve housing 412, the connection between the valve housing 412 and the valve sleeve 413, and the connection between the valve sleeve 413 and the valve cover 411.

[0047] The end face of the limiting ring 43 away from the shell 1 is a bevel, and the diameter of the bevel gradually decreases away from the shell 1, so as to reduce the resistance when the valve core 42 moves.

[0048] Working principle:

[0049] As shown in Figure 4 , the follow-up valve 4 is in the initial state, and the valve core 42 is in the left limit position under the action of the spring 44. The throttle hole 423 is completely misaligned with the annular groove 4132 in the slide hole 4131, and the throttle opening is in the closed state.

[0050] As shown in Figure 5 , the follow-up valve 4 is in the working state. The hydraulic oil returned from the sealing cavity 25 through the oil outlet pipe 5 enters the valve core mounting hole 4124 through the oil inlet port 4121 and acts on the left side of the valve core 2. Since the throttle opening of the follow-up valve 4 is in the closed state in the initial state, the pressure of the hydraulic oil entering the valve core 42 must be increased. After the spring 44 is compressed, the valve core 42 moves to the right, the throttle hole 423 corresponds to the annular groove 4132, and the hydraulic oil is throttled and flows out through the annular groove 4132, the oil return channel 4133 and the oil return port 4122.

[0051] When the follow-up valve 4 is in normal working state, the influence of gravity and friction is ignored, the valve core 42 is subjected to the pressure of the hydraulic oil, the spring 44 and the pressure of the mud in the well, and is in a state of force balance.

[0052] When the mud pressure in the well is zero, the oil pressure acting on the valve core 42 is equal to the counterforce of the spring 44, at this time the oil pressure is a fixed value. When the mud pressure in the well has a certain pressure, the pressure acts on the right side of the valve core 42, so that the valve core 42 moves left, the throttling hole 423 overlaps with the annular groove 4132, the throttling opening becomes smaller, the throttling opening becomes smaller, the oil pressure rises to a new balance point, at this time the oil pressure needs to overcome the counterforce generated by the spring 44 and the action force generated by the well pressure, since the effective areas of the two sides of the valve core 42 are equal, at this time the oil pressure will be slightly higher than the well pressure, this slightly higher pressure is to balance the counterforce generated by the spring 44, so that the oil pressure in the sealing cavity 25 is higher than the well pressure, the mud in the well will not enter the lower dynamic sealing ring 24, preventing the lower dynamic sealing ring 24 from being damaged, prolonging the service life of the lower dynamic sealing ring 24.

[0053] When the mud pressure in the well rises, the valve core 42 will be pushed to move left, so that the throttling opening becomes smaller, the throttling opening becomes smaller, so that the oil pressure rises, when the mud pressure in the well decreases, the oil pressure will push the valve core 42 to move right, so that the throttling opening becomes larger, the throttling opening becomes larger, so that the oil pressure decreases, in summary, through the adjusting effect of the valve core 42 in the follow-up valve 4, during work, the oil pressure can always be slightly higher than the well pressure, and changes with the change of the well pressure, thereby enhancing the sealing effect at the lower dynamic sealing ring 24.

[0054] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same and similar parts between various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0055] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A pressure-following rotary blowout preventer, characterized by, Include: The shell (1); the shell (1) top is provided with a center hole, the side wall is provided with a slurry outlet (11); Rotary assembly (2), the rotary assembly (2) includes fixed sleeve (21) and rotary head (22), the fixed sleeve (21) is connected in the center hole, the upper end inner wall of the fixed sleeve (21) is installed with upper dynamic sealing ring (23), the lower end inner wall is installed with lower dynamic sealing ring (24), the rotary head (22) upper portion is rotatably installed in the fixed sleeve (21), and its outer side wall and the upper dynamic sealing ring (23) and lower dynamic sealing ring (24) form a sealed cavity (25), the rotary head (22) outer side wall is installed with bearing (26) corresponding to the sealed cavity (25); The fixed sleeve (21) upper portion is provided with oil outlet hole (27) communicating with the sealed cavity (25), the lower portion is provided with oil inlet hole (28) communicating with the sealed cavity (25), and the oil inlet hole (28) is communicated with the hydraulic control equipment through the oil inlet pipe (3); Follow-up valve (4), follow-up valve (4) includes valve body (41), valve core (42), limit ring (43) and spring (44), the valve body (41) is closed at both ends of the barrel type structure, one end is fixed on the outer wall of the shell (1), and the end of one end is provided with a sliding hole (4131) communicated with the slurry outlet (11); The side wall of the valve body (41) is provided with an oil inlet (4121) communicated with its inner cavity, and an oil return port (4122) communicated with the sliding hole (4131) is provided corresponding to the sliding hole (4131), the oil inlet (4121) is communicated with the oil outlet hole (27) through the oil outlet pipe (5); The valve core (42) is slidably connected in the sliding hole (4131) along the axial direction of the sliding hole (4131), the other end extends into the inner cavity of the valve body (41), and the other end is provided with a valve core oil hole (421), the valve core oil hole (421) is a blind hole; The side wall of the valve core (42) is provided with an oil inlet channel (422) communicated with the valve core oil hole (421) and the inner cavity of the valve body (41) corresponding to the inner cavity of the valve body (41), and a throttle hole (423) communicated with the valve core oil hole (421) and the oil return port (4122) is provided corresponding to the sliding hole (4131); The limit ring (43) is fixed on the other end of the valve core (42), and the outer ring wall thereof is slidably connected with the inner side wall of the valve body (41), and the spring (44) is sleeved on the valve core (42) between the limit ring (43) and the inner wall of the valve body (41) close to the shell (1) one end.

2. A pressure-following rotary flare according to claim 1, characterized in that The valve body (41) includes: Valve cover (411), one end of the valve cover (411) is fixed on the side wall of the shell (1) and is provided with a slurry inlet (4111) communicated with the slurry outlet (11); A valve shell (412) in a closed-end cylinder structure, and its open end is fixed to the other end of the valve cover (411), the inner cavity of the valve shell (412) is a stepped hole, which includes a valve sleeve mounting hole (4123) and a valve core mounting hole (4124) arranged in turn and communicated with each other from the open end to the closed end, the hole diameter of the valve sleeve mounting hole (4123) is larger than that of the valve core mounting hole (4124) to form a shoulder at the connection, the oil inlet (4121) is opened at the valve shell (412) corresponding to the valve core mounting hole (4124) and communicated with the valve core mounting hole (4124), and the oil return port (4122) is opened at the valve shell (412) corresponding to the valve sleeve mounting hole (4123) and communicated with the valve sleeve mounting hole (4123); A valve sleeve (413) is installed in the valve sleeve mounting hole (4123), and one end abuts against the shoulder of the valve cover (411), and the other end abuts against the valve cover (411), the inner cavity of the valve sleeve (413) is the sliding hole (4131) and the sliding hole (4131) is communicated with the mud inlet (4111), the inner wall of the valve sleeve (413) is provided with an annular groove (4132) corresponding to the oil return port (4122), the bottom of the annular groove (4132) is provided with an oil return channel (4133) communicated with the oil return port (4122), and the other end of the spring (44) abuts against the end face of the valve sleeve (413) away from the shell (1).

3. A pressure-following rotary flare according to claim 2, wherein, The diameter of the mud inlet (4111) gradually decreases away from the shell (1).

4. A pressure-following rotary flare according to claim 2, wherein An oil delivery channel (422) is further opened on the side wall of the valve shell (412), the oil inlet end of the oil delivery channel (422) is connected with the hydraulic control device, and the oil outlet end is communicated with the oil inlet pipe (3).

5. A pressure-following rotary flare according to claim 2, wherein The connection between the valve cover (411) and the mud outlet (11), the connection between the valve cover (411) and the valve shell (412), the connection between the valve shell (412) and the valve sleeve (413), and the connection between the valve sleeve (413) and the valve cover (411) are all provided with a sealing ring (6).

6. A pressure-following rotary blowout preventer according to any one of claims 1-5, characterized in that, The end face of the limiting ring (43) away from the shell (1) is a bevel, and the diameter of the bevel gradually decreases away from the shell (1).

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