CN111536237A - Eccentric rotation following sealing device of rotary blowout preventer - Google Patents

Abstract

The invention discloses an eccentric rotation following sealing device of a rotary blowout preventer, which comprises a shell sleeved outside a rotating shaft, wherein an upper cover and a lower cover are respectively arranged at the upper end and the lower end of the shell, a sealing cavity is formed between the upper cover and the lower cover, a following sealing element and a compensating sealing element are sequentially sleeved in the sealing cavity from inside to outside, the middle part of the compensating sealing element protrudes towards the following sealing element and forms a hydraulic cavity with the inner side of the shell, and a liquid inlet hole communicated with the hydraulic cavity is formed in the side wall of the shell. By adopting the structure, the deformation of the compensation sealing element is extruded by hydraulic pressure, the follow-up sealing element is continuously compensated, when the rotating shaft generates unpredictable eccentric swing in the radial direction under the action of external force, the sealing lip edge of the follow-up sealing element is always ensured to be tightly attached to the rotating shaft, the sealing surface does not leak, the sealing effect is ensured, and the service life of the sealing element is prolonged.

Description

Eccentric rotation following sealing device of rotary blowout preventer

Technical Field

The invention relates to the technical field of blowout preventers, in particular to an eccentric rotation following sealing device of a rotary blowout preventer.

Background

In the current field of oil drilling and exploitation, a rotary blowout preventer must be installed and used at a drilling wellhead to implement underbalance (gas phase and liquid phase) and air pressure drilling operation. The rotary seal core component of the rotary blowout preventer mainly comprises a rotary mandrel, a rotary seal assembly and a fixed shell, wherein the rotary seal assembly between the rotary mandrel and the fixed shell is a key component for ensuring the service life and the reliability of the rotary blowout preventer. In the drilling process, once the rotary sealing assembly of the rotary blowout preventer fails, the rotary blowout preventer and the rotary sealing assembly thereof must be stopped immediately to replace, which wastes drilling time and increases safety risks in the drilling process.

At present, in a drilling operation site, due to wellhead eccentricity and transverse irregular vibration of a drilling tool, instantaneous large eccentric gaps are easy to occur between rotating parts and non-rotating parts of the rotary blowout preventer, and when the gaps exceed the elastic medium sealing compensation range of the rotary sealing assembly, the rotary sealing assembly at the position of a rotating shaft is subjected to sealing failure. The known prior rotary sealing technology generally adopts wear-resistant sealing materials, and presses a lip edge of a rotary sealing assembly by means of elastic compression force of a supporting part such as rubber or a metal spring to compensate a gap between the rotary sealing assembly and a rotating shaft in the rotating process due to abrasion; meanwhile, in the use process, along with the continuous abrasion of the rotating seal contact surface, before the sealing lip is not completely abraded, the elasticity of the supporting elastic medium cannot achieve the expected compensation effect, so that the leakage of the seal is caused, and the service life of the seal is influenced. A dynamic sealing device for a rotary blowout preventer, which is disclosed in Chinese patent publication No. CN201110382073.8, published as 2012, 2 and 29, has the technical scheme that a support ring is arranged in a packing box, an oil hole b and an oil hole c are arranged on the support ring, and an annular groove b is arranged on the outer surface of the support ring; the disc spring is arranged in the supporting ring, the lower part of the disc spring is provided with a spacing ring, and the supporting ring is arranged between the spacing ring and the pressing ring; the pressing ring is provided with an oil hole a, and the lower part of the pressing ring is sequentially provided with a V-shaped sealing ring and a space ring at intervals; the lower end of the floating ring is provided with a packing pressing ring which is fixed at the end part of a packing box, and the packing pressing ring is in clearance fit with the central pipe bush; the central pipe bush is in interference fit with the central pipe, the packing box is in interference fit with the upper shell of the blowout preventer, and lubricating oil enters the oil hole of the upper shell of the blowout preventer through the bearing. The device reduces the abrasion of the surface of the sealing element and reduces the self heating of the sealing element by adopting a combined sealing structure so as to prolong the service life of the sealing element, but the sealing surface clearance is still performed by adopting elastic material to elastically deform and press the lip edge of the sealing element, so that the problem cannot be avoided in the using process.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an eccentric rotation following sealing device of a rotary blowout preventer, which transmits hydraulic pressure to a following sealing element through a compensating sealing element and an auxiliary sealing element, and continuously compensates the sealing lip edges of the following sealing element, so that the sealing lip edges of the following sealing element are always tightly attached to a rotating shaft before being completely worn, thereby ensuring the sealing performance.

The technical scheme adopted by the invention is as follows:

the eccentric rotation following sealing device of the rotary blowout preventer comprises a shell sleeved outside a rotating shaft, wherein an upper cover and a lower cover are respectively installed at the upper end and the lower end of the shell, a sealing cavity is formed between the upper cover and the lower cover, a following sealing piece and a compensating sealing piece are sequentially sleeved in the sealing cavity from inside to outside, a hydraulic cavity is formed between the middle of the compensating sealing piece and the inner side of the shell, the middle of the compensating sealing piece protrudes towards the following sealing piece, and a liquid inlet hole communicated with the hydraulic cavity is formed in the side wall of the shell.

Preferably, the lower end face of the upper cover and the upper end face of the lower cover are respectively provided with an upper sealing sleeve and a lower sealing sleeve, and a sealing cavity is formed between the upper sealing sleeve and the lower sealing sleeve.

Preferably, a framework for supporting the compensation sealing element is arranged in the hydraulic cavity.

Preferably, the upper end and the lower end of the inner side of the convex part of the compensation sealing element are provided with steps which are concave towards the direction of the hydraulic cavity, and the lower end surface of the upper sealing sleeve and the upper end surface of the lower sealing sleeve are respectively provided with steps which are matched with the two steps of the compensation sealing element.

Preferably, an auxiliary seal is further arranged between the following seal and the compensation seal.

Preferably, an upper static sealing element and a lower static sealing element are respectively arranged between the outer side ring surface of the upper sealing sleeve and the outer side ring surface of the lower sealing sleeve and the inner side ring surface of the shell.

Preferably, a following seal positioning mechanism for fixing the following seal is arranged between the lower end face of the upper seal sleeve and the upper end face of the following seal or between the upper end face of the lower seal sleeve and the lower end face of the following seal.

Preferably, the following seal positioning mechanism comprises a lower end face of the upper seal sleeve and an upper end face of the following seal member or an upper end face of the lower seal sleeve and a lower end face of the following seal member, wherein the lower end face of the upper seal sleeve and the upper end face of the following seal member or the upper end face of the lower seal sleeve and the lower end face of the following seal member are respectively provided with a clamp pin hole, and a seal member clamp pin is arranged in the clamp pin hole of.

Preferably, the outer side of the following sealing piece opposite to the clamping pin hole on the following sealing piece is provided with an inward concave step, and the auxiliary sealing piece is arranged at the step of the following sealing piece.

The invention has the beneficial effects that:

1. by adopting the structure, the deformation of the compensation sealing element is extruded by hydraulic pressure, the follow-up sealing element is continuously compensated, when the rotating shaft generates unpredictable eccentric swing in the radial direction under the action of external force, the sealing lip edge of the follow-up sealing element is always ensured to be tightly attached to the rotating shaft, the sealing surface does not leak, the sealing effect is ensured, and the service life of the sealing element is prolonged;

2. by adopting the structure, the following sealing element can not damage the sealing element because the rotating shaft drives the following sealing element to rotate together due to the large contact friction force between the lip edge of the following sealing element and the rotating shaft under the fixing action of the sealing element clamping pin and the sealing sleeve;

3. the compensation sealing element is made of elastic materials, the front cavity and the rear cavity of the compensation sealing element are mutually isolated through the upper sealing sleeve step and the lower sealing sleeve step and the sealing action, the compensation sealing element is pressed to assist sealing and follow sealing under the action of pressure oil in the rear sealing cavity, and the lip edge of the follow sealing element is ensured to be always contacted with the rotating shaft due to constant pressure and continuous source of the pressure oil, so that the follow sealing effect is ensured;

4. the size of the pressure oil borne by the compensation sealing element corresponds to the sealing pressure between the following sealing element and the rotating shaft, the value cannot be too high or too low, the size of the pressure oil can just ensure the sealing performance of the following sealing element, and meanwhile, the sealing contact surface cannot generate large friction to lock the rotating shaft, and if the sealing pressure of the sealing contact surface is constant, the pressure value is also constant;

5. the framework arranged on the outer side of the compensating sealing element can ensure that the integral structure of the compensating sealing element is not damaged due to the fact that the framework supports the compensating sealing element to be not deformed beyond the limit when the compensating sealing element is pressed, and meanwhile, the shape of the compensating sealing element is not changed when no pressure exists;

6. the auxiliary sealing element can adopt a special structure with a rectangular section, and can also be directly replaced by stacking a plurality of O-shaped sealing rings;

7. the upper cover, the lower cover, the shell, the upper sealing sleeve, the lower sealing sleeve and the sealing component adopt a split combined structure, and the replacement and the maintenance are convenient.

Drawings

FIG. 1 is a schematic structural view of an embodiment of a compensator seal in an uncompressed state;

FIG. 2 is a schematic view of a pressurized state of a compensating seal according to an embodiment of the present invention;

reference numerals: 1. the sealing device comprises a rotating shaft, 2, an upper cover, 3, a shell, 4, an upper static seal, 5, a framework, 6, a compensation seal, 7, a lower static seal, 8, an upper sealing sleeve, 9, a seal clamping pin, 10, a following seal, 11, an auxiliary seal, 12, a lower sealing sleeve, 13 and a lower cover.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Examples

As shown in fig. 1, the eccentric rotation following sealing device of the rotary blowout preventer comprises ashell 3 sleeved outside a rotating shaft 1, wherein anupper cover 2 and alower cover 13 are respectively installed at the upper end and the lower end of theshell 3, a sealing cavity is formed between theupper cover 2 and thelower cover 13, a followingsealing element 10 and a compensatingsealing element 6 are sequentially sleeved in the sealing cavity from inside to outside, a hydraulic cavity is formed between the middle part of the compensatingsealing element 6, which protrudes towards the followingsealing element 10, and the inner side of theshell 3, and a liquid inlet hole communicated with the hydraulic cavity is formed in the side wall of theshell 3.

The followingsealing member 10 is made of wear-resistant and pressure-resistant material, a sealing lip with saw teeth is arranged on the inner side of the following sealing member and is in contact with the cylindrical surface of the rotating shaft 1 to form a sealing surface, and the rotating shaft 1 rotates to implement rotary sealing. Thecompensation sealing member 6 is made of oil-resistant rubber material with certain strength and elasticity, and theupper cover 2, thelower cover 13, theshell 3 and thecompensation sealing member 6 form a hydraulic cavity together on the outer side of thecompensation sealing member 6. As shown in figure 2, controlled pressure oil flows into a hydraulic cavity through a liquid inlet hole, the compensatingseal member 6 is deformed under pressure and extrudes the followingseal member 10, so that the lip edge of the inner side of the followingseal member 10 is kept attached to the rotating shaft 1, different compensating pressures can be controlled according to the actual sealing pressures of the followingseal member 10 and the rotating shaft 1, the lip edge of the followingseal member 10 can be ensured to be always closely attached to the rotating shaft 1 before being completely worn, meanwhile, the sealing contact surface cannot leak, and the rotating shaft 1 cannot be locked.

The inner sides of the upper and lower ends of thehousing 3 can be provided with steps for bearing theupper cover 2 and thelower cover 13, and theupper cover 2 and thelower cover 13 can be detachably and fixedly connected with thehousing 3 through bolts or other connection modes.

In one embodiment, the lower end surface of theupper cover 2 and the upper end surface of thelower cover 13 are respectively provided with anupper sealing sleeve 8 and alower sealing sleeve 12, and a sealing cavity is formed between theupper sealing sleeve 8 and thelower sealing sleeve 12.

Theupper sealing sleeve 8 and thelower sealing sleeve 12 are fixed in thehousing 3 through theupper cover 2 and thelower cover 13, respectively, and the sealing performance of the inner side of thehousing 3 can be enhanced through theupper sealing sleeve 8 and thelower sealing sleeve 12.

In one embodiment, aframework 5 for supporting a compensatingseal 6 is provided within the hydraulic chamber.

The radial section of the compensatingseal 6 is in a transverse convex shape protruding towards the rotating shaft 1, and theframework 5 is arranged in an annular groove with a rectangular outer section of the compensatingseal 6, so that the overall structure of the compensatingseal 6 cannot be damaged due to deformation exceeding the limit caused by the support of theframework 5 when the compensatingseal 6 is pressed, and the shape of the compensatingseal 6 cannot be changed under the condition of no pressing.

In one embodiment, the upper and lower ends of the inner side of the convex portion of the compensatingseal 6 have steps recessed toward the hydraulic chamber, and the lower end surface of theupper sealing sleeve 8 and the upper end surface of thelower sealing sleeve 12 are respectively provided with steps matched with the two steps of the compensatingseal 6.

The compensatingseal 6 with itsframe 5 is arranged between anupper gland 8 and alower gland 12 having steps, the steps of theupper gland 8 and thelower gland 12 serving to secure the compensatingseal 6 while ensuring the hydraulic chamber between the compensatingseal 6 and thehousing 3 is closed

In one embodiment, anauxiliary seal 11 is also provided between thefollower seal 10 and thecompensator seal 6.

The auxiliary sealing is made of high-temperature-resistant elastic materials and is arranged on the outer side of the followingsealing piece 10, the auxiliary sealing is used for preventing sealing media from entering a cavity of the compensatingsealing piece 6, the lip edge of the followingsealing piece 10 is always attached to the rotating shaft 1 by means of the elasticity of the auxiliary sealing piece and the extrusion force transmitted by the compensatingsealing piece 6, the following performance of the followingsealing piece 10 is guaranteed, theauxiliary sealing piece 11 can be customized to be of a special structure with a rectangular radial section, and a plurality of O-shaped sealing rings can be directly used for stacking and replacing the sealing pieces.

In one embodiment, an upperstatic seal 4 and a lowerstatic seal 7 are respectively arranged between the outer side ring surface of theupper sealing sleeve 8 and thelower sealing sleeve 12 and the inner side ring surface of theshell 3.

The upperstatic seal 4 and the lowerstatic seal 7 which are arranged on theupper sealing sleeve 8 and thelower sealing sleeve 12 and the compensatingseal 6, the upper sealing cover, the lower sealing cover and theshell 3 form a closed hydraulic cavity together outside the compensatingseal 6, controlled pressure oil flows through the hydraulic cavity to make the compensatingseal 6 deform under pressure, and the lip edge of the followingseal 10 is extruded to keep being attached to the rotating shaft 1 under the transmission action of theauxiliary seal 11, different compensating pressures can be controlled according to the actual sealing pressures of the followingseal 10 and the rotating shaft 1, the lip edge of the followingseal 10 can be ensured to be always closely attached to the rotating shaft 1 before being completely worn, meanwhile, the leakage of a sealing contact surface can not occur, and the rotating shaft 1 can not be locked.

In one embodiment, a follower seal positioning mechanism for fixing thefollower seal 10 is arranged between the lower end face of theupper seal sleeve 8 and the upper end face of thefollower seal 10 or between the upper end face of thelower seal sleeve 12 and the lower end face of thefollower seal 10.

In one embodiment, the following seal positioning mechanism comprises a lower end face of anupper seal sleeve 8, an upper end face of a followingseal member 10, an upper end face of alower seal sleeve 12 and a lower end face of the followingseal member 10, which are respectively provided with a pin clamping hole, and aseal member pin 9 is arranged in the pin clamping hole of theupper seal sleeve 8 and the followingseal member 10 or the pin clamping hole of thelower seal sleeve 12 and the followingseal member 10.

In one embodiment, the outer side of thefollower seal member 10 opposite to the snap pin hole of thefollower seal member 10 has an inwardly recessed step, and theauxiliary seal member 11 is disposed at the step of thefollower seal member 10.

As shown in fig. 1, thefollower seal 10 is fixed on theupper seal cover 8 by theseal pin 9, and theseal pin 9 is used for preventing thefollower seal 10 from being damaged due to the friction force of the contact surface of thefollower seal 10 and the rotating shaft 1, and thefollower seal 10 is driven by the rotating shaft 1 to rotate along with the rotating shaft. Theauxiliary seal 11 is arranged at the step at the lower outer corner of the followingseal 10, but not at the middle of the followingseal 10, so as to avoid that the middle of the followingseal 10 is directly extruded to cause that the followingseal 10 is deformed too much and is separated from theupper sealing sleeve 8.

The above-mentioned embodiments only express the specific embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims (9)

1. The utility model provides a sealing device is followed in rotatory preventer eccentric rotation, its characterized in that, including suit shell (3) outside rotation axis (1), upper cover (2) and lower cover (13) are installed respectively to the upper and lower both ends of shell (3), form the seal chamber between upper cover (2) and lower cover (13), from interior to exterior in proper order the cover is equipped with and follows sealing member (10) and compensation sealing member (6) in the seal chamber, the middle part of compensation sealing member (6) to following sealing member (10) protruding and with shell (3) inboard between form the hydraulic pressure chamber, the lateral wall of shell (3) is equipped with the feed liquor hole with hydraulic pressure chamber intercommunication.

2. The eccentric rotary-following sealing device of a rotary blowout preventer according to claim 1, characterized in that the lower end face of the upper cap (2) and the upper end face of the lower cap (13) are respectively an upper sealing sleeve (8) and a lower sealing sleeve (12), a sealing cavity being formed between the upper sealing sleeve (8) and the lower sealing sleeve (12).

3. The eccentric rotary follower seal arrangement of a rotary blowout preventer according to claim 2, characterized in that a backbone (5) for supporting the compensating seal (6) is provided in the hydraulic chamber.

4. The eccentric rotary follower seal device of a rotary blowout preventer according to claim 2, characterized in that the upper and lower ends of the inner side of the convex part of the compensating seal (6) have steps that are concave towards the hydraulic chamber, and the lower end surface of the upper gland (8) and the upper end surface of the lower gland (12) are provided with steps that cooperate with the two steps of the compensating seal (6), respectively.

5. The eccentric rotary follower sealing device of a rotary blowout preventer according to claim 1, characterized in that an auxiliary seal (11) is further provided between the follower seal (10) and the compensating seal (6).

6. The eccentric rotary follower sealing device of rotary blowout preventers according to claim 1, characterised in that between the outer annular surface of the upper and lower sealing sleeves (8, 12) and the inner annular surface of the casing (3) there are respectively provided an upper static seal (4) and a lower static seal (7).

7. The eccentric rotary follower seal arrangement of a rotary blowout preventer according to claim 5, characterized in that a follower seal positioning mechanism for fixing the follower seal (10) is provided between the lower end face of the upper gland (8) and the upper end face of the follower seal (10) or between the upper end face of the lower gland (12) and the lower end face of the follower seal (10).

8. The eccentric rotation following sealing device of the rotary blowout preventer according to claim 7, wherein the following sealing positioning mechanism comprises a lower end face of an upper sealing sleeve (8) and an upper end face of a following sealing member (10) or an upper end face of a lower sealing sleeve (12) and a lower end face of the following sealing member (10) which are respectively provided with a clamping pin hole, and a sealing member clamping pin (9) is arranged in the clamping pin hole of the upper sealing sleeve (8) and the following sealing member (10) or the clamping pin hole of the lower sealing sleeve (12) and the following sealing member (10).

9. The eccentric rotary follower seal arrangement of a rotary blowout preventer according to claim 8, characterized in that the outer side of the follower seal (10) opposite to the snap pin hole on the follower seal (10) has an inwardly recessed step, and the auxiliary seal (11) is provided at the step of the follower seal (10).

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