Liftable drilling fluid collecting device

Abstract

The utility model discloses a liftable drilling fluid collecting device, which relates to the technical field of drilling equipment, and aims to solve the problem that the existing drilling fluid collecting device cannot meet the requirements of different installation heights, the device comprises an outer sleeve which is of a hollow structure and is fixed on a blowout preventer, and a fluid collecting barrel which is of a hollow structure and is fixed on the blowout preventer. The liquid collecting cylinder is sleeved with the outer sleeve in a liftable mode, a liquid inlet used for collecting drilling fluid is formed in the top of the liquid collecting cylinder, a liquid outlet is formed in the circumferential direction of the liquid collecting cylinder and is close to the liquid inlet, the lifting device is arranged on the outer sleeve, and the output end of the lifting device is connected with the liquid collecting cylinder so as to drive the liquid collecting cylinder to ascend and descend.

Description

Technical Field

[0001] The utility model relates to the technical field of drilling equipment, and more specifically, to a liftable drilling fluid collection device. Background Technique

[0002] Drilling fluid is the circulating flushing medium used in the borehole during the drilling process. Drilling fluid is the blood of drilling, also known as borehole flushing fluid. Drilling fluid can be divided into clear water, mud, clay-free flushing fluid, emulsion, etc. according to its composition. Clear water is the earliest used drilling fluid, which does not require treatment and is convenient to use, and is suitable for intact rock formations and areas with sufficient water sources. Mud is a widely used drilling fluid, mainly suitable for unstable borehole walls such as loose, fissure-developed, easily caving and sloughing, and swelling and exfoliating when encountering water.

[0003] At present, with the further deepening of domestic oil development, the number of oil wells has gradually increased. The drilling fluid collection device is a great tool to meet the environmental protection requirements of oil drilling. It can re-collect the drilling fluid dripping on the drill floor and return it to the circulation system, which can reduce the loss of drilling fluid and prevent the drilling fluid from dripping on the ground and causing land pollution. The clearances under the drill floors of existing drilling rigs are different, and different wellhead blowout preventer groups are used for the same drilling rig at different well positions, resulting in different installation heights of the drilling fluid collection device. This requires making drilling fluid collection devices with multiple heights to meet the usage requirements of different installation heights, but it will increase the cost of making the drilling fluid collection device. That is to say, the existing drilling fluid collection device cannot meet the requirements of different installation heights. When the installation platform is relatively high, the drilling fluid collection device is likely to be unable to be installed due to height problems. When the installation platform is relatively low, it is likely to cause problems with poor collection effect of the drilling fluid collection device.

[0004] Therefore, how to solve the problem that the existing drilling fluid collection device cannot meet the requirements of different installation heights is an urgent problem to be solved by those skilled in the art at present. Content of the Utility Model

[0005] In view of this, the purpose of the utility model is to provide a liftable drilling fluid collection device, which can meet the requirements of various installation heights and greatly reduce the problems that the drilling fluid collection device cannot be installed or has a poor collection effect due to the installation height.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A liftable drilling fluid collection device, comprising:

[0008] An outer sleeve, which is a hollow structure and is fixed on the blowout preventer;

[0009] The liquid collection cylinder is of a hollow structure. The liquid collection cylinder is sleeved in the outer sleeve in a liftable manner. The top of the liquid collection cylinder is provided with a liquid inlet for collecting drilling fluid. The circumferential direction of the liquid collection cylinder is provided with a liquid discharge port, and the liquid discharge port is arranged close to the liquid inlet.

[0010] The lifting device is arranged on the outer sleeve. The output end of the lifting device is connected to the liquid collection cylinder to drive the lifting movement of the liquid collection cylinder.

[0011] Preferably, the liquid discharge port is connected to the first interface of the three-way joint through a return slurry pipeline. The second interface of the three-way joint is connected to the drilling fluid elevated tank, and the third interface of the three-way joint is connected to the blowout preventer.

[0012] Preferably, the lifting device is a hydraulic device. There are at least two hydraulic devices, and at least two hydraulic devices are evenly arranged in the circumferential direction of the outer sleeve. The hydraulic devices are all connected to the power source through oil circuits. A hydraulic distributor is arranged on the oil circuit, and a reversing valve is arranged on the power source.

[0013] Preferably, the hydraulic device includes a hydraulic cylinder and a hydraulic rod movably arranged in the hydraulic cylinder. The hydraulic cylinder is fixed to the outer sleeve, and the output end of the hydraulic rod is hinged to the liquid collection cylinder. The hydraulic cylinder is connected to the power source through an oil circuit.

[0014] Preferably, at least two groups of installation structures for installing hydraulic cylinders are arranged in the circumferential direction of the outer sleeve. Any group of installation structures includes two installation piles arranged collinearly along the height direction of the outer sleeve.

[0015] Preferably, the liquid collection cylinder includes an inner sleeve sleeved in the outer sleeve in a liftable manner and a liquid collection barrel arranged at the top of the inner sleeve. The liquid collection barrel is of an inverted frustum structure. Hinges are arranged on the circumferential direction of the top of the inner sleeve, and the hinges are hinged to the output ends of the hydraulic rods.

[0016] Preferably, a flange is arranged on the circumferential direction of the top end of the inner sleeve, and a flange is also arranged on the circumferential direction of the bottom end of the liquid collection barrel. The inner sleeve and the liquid collection barrel are connected through flanges and bolts, and the inner sleeve and the liquid collection barrel are sealed with steel rings.

[0017] Preferably, an annular groove group is arranged on the outer periphery of the bottom of the inner sleeve, and sealing rings are arranged in the annular groove group.

[0018] Preferably, the annular groove group includes two first annular grooves and one second annular groove. The first annular grooves are arranged on the upper and lower sides of the second annular groove. YX-type sealing rings are arranged in the first annular grooves, and O-type sealing rings are arranged in the second annular groove.

[0019] Preferably, the outer sleeve is of a cylindrical structure, and the bottom of the outer sleeve has an inverted frustum-shaped contraction structure. A flange is arranged on the outer periphery of the bottom end of the contraction structure.

[0020] The liftable drilling fluid collection device provided by the present utility model includes an outer sleeve, a liquid collection cylinder, and a lifting device. Specifically, both the outer sleeve and the liquid collection cylinder are hollow structures, providing conditions for the collection and circulation of drilling fluid. The outer sleeve is fixed to the blowout preventer, and the liquid collection cylinder is liftably sleeved inside the outer sleeve. The lifting device is arranged in the outer sleeve and its output end is connected to the liquid collection cylinder to drive the lifting movement of the liquid collection cylinder. The liquid collection cylinder is set as a liftable structure to meet the requirements of different installation heights, improve the applicable range of the drilling fluid collection device, and avoid problems such as the inability to install or poor collection effect caused by the installation height of the drilling fluid collection device. The top of the liquid collection cylinder is provided with a liquid inlet for collecting drilling fluid, and a liquid discharge port is arranged circumferentially on the liquid collection cylinder. The liquid discharge port is arranged close to the liquid inlet. The drilling fluid at the rotary table of the drill floor will flow into the liquid collection cylinder from the liquid inlet at the top of the liquid collection cylinder and accumulate inside the liquid collection cylinder. When the drilling fluid accumulates to a height level with the liquid discharge port, the subsequent accumulated drilling fluid will be discharged from the liquid discharge port of the liquid collection cylinder.

[0021] The liftable drilling fluid collection device arranged in the above manner has the liquid collection cylinder liftably arranged in the outer sleeve driven by the lifting device to meet the requirements of various installation heights. When the height of the installation platform is relatively low, the liquid collection cylinder is driven by the lifting device to rise to a suitable position to avoid the problem of reduced collection effect of drilling fluid due to too large a height difference between the liquid collection cylinder and the drill pipe. When the height of the installation platform is relatively high, the liquid collection cylinder is driven by the lifting device to descend to a suitable position to avoid the inability to install the drilling fluid collection device due to the excessive height of the drilling fluid collection device. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative efforts.

[0023] Figure 1 It is a schematic structural diagram of the liftable drilling fluid collection device provided by the present utility model;

[0024] Figure 2 It is a schematic installation structure diagram of the liftable drilling fluid collection device provided by the present utility model;

[0025] Figure 3 It is a cross-sectional view of the liftable drilling fluid collection device provided by the present utility model;

[0026] Figure 4 It is a cross-sectional view of the liquid collection cylinder provided by the present utility model;

[0027] Figure 5It is a partial enlarged view of the inner sleeve provided by the present utility model;

[0028] Figure 6 It is a cross-sectional view of the outer sleeve provided by the present utility model.

[0029] Reference numerals:

[0030] 1 - Outer sleeve;

[0031] 2 - Liquid collecting cylinder, 21 - Inner sleeve, 22 - Liquid collecting barrel, 201 - Liquid inlet, 202 - Liquid outlet;

[0032] 3 - Lifting device, 31 - Hydraulic cylinder, 32 - Hydraulic rod;

[0033] 4 - Return slurry pipeline;

[0034] 5 - Installation pile;

[0035] 6 - Hinge;

[0036] 7 - Annular groove group, 71 - First annular groove, 72 - Second annular groove;

[0037] 8 - YX type sealing ring;

[0038] 9 - O type sealing ring. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0040] In the present utility model, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and other terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0041] It should be noted that the following orientation words such as "up" and "down" are defined based on the accompanying drawings of the specification.

[0042] The core of the present utility model is to provide a liftable drilling fluid collection device, which can meet the requirements of various installation heights, and greatly reduce the problems that the drilling fluid collection device cannot be installed or has poor collection effect due to the installation height.

[0043] Please refer to Figure 1 , a liftable drilling fluid collection device includes an outer sleeve 1, a liquid collection cylinder 2 and a lifting device 3.

[0044] Specifically, both the outer sleeve 1 and the liquid collection cylinder 2 are of hollow structures, providing conditions for the collection and circulation of drilling fluid. The outer sleeve 1 is fixed on the blowout preventer, and the liquid collection cylinder 2 is liftably sleeved inside the outer sleeve 1. The lifting device 3 is arranged in the outer sleeve 1 and its output end is connected to the liquid collection cylinder 2 to drive the lifting movement of the liquid collection cylinder 2. The liquid collection cylinder 2 is set as a liftable structure to meet the requirements of different installation heights, improve the applicable range of the drilling fluid collection device, and avoid the problems that the drilling fluid collection device cannot be installed or has poor collection effect due to the installation height. A liquid inlet 201 for collecting drilling fluid is provided at the top of the liquid collection cylinder 2, and a liquid discharge port 202 is provided on the circumference of the liquid collection cylinder 2. The liquid discharge port 202 is arranged close to the liquid inlet 201. The drilling fluid at the rotary table on the drill floor will flow into the liquid collection cylinder 2 from the liquid inlet 201 at the top of the liquid collection cylinder 2 and accumulate inside the liquid collection cylinder 2. When the drilling fluid accumulates to a height level with the liquid discharge port 202, the subsequent accumulated drilling fluid will be discharged from the liquid discharge port 202 of the liquid collection cylinder 2.

[0045] Among them, the blowout preventer is a rotating blowout preventer, including a housing and a rotating assembly. The outer sleeve 1 is fixed on the housing. When the rotating assembly is seated in the housing, the drilling fluid at the rotary table on the drill floor will flow into the liquid collection cylinder 2 from the liquid inlet 201 at the top of the liquid collection cylinder 2 and accumulate inside the liquid collection cylinder 2. When the drilling fluid accumulates to a height level with the liquid discharge port 202, the subsequent accumulated drilling fluid will be discharged from the liquid discharge port 202 of the liquid collection cylinder 2; when the rotating assembly is not seated in the housing, the drilling fluid at the rotary table on the drill floor will flow into the wellbore.

[0046] The liftable drilling fluid collection device arranged in the above way drives the liquid collection cylinder 2 to be liftably arranged in the outer sleeve 1 through the lifting device 3 to meet the requirements of various installation heights. When the height of the installation platform is relatively low, the liquid collection cylinder 2 is driven by the lifting device 3 to rise to a suitable position to solve the problem that the collection effect of the drilling fluid is reduced due to the excessive height difference between the liquid collection cylinder 2 and the drill pipe. When the height of the installation platform is relatively high, the liquid collection cylinder 2 is driven by the lifting device 3 to descend to a suitable position to solve the problem that the drilling fluid collection device cannot be installed due to the excessive height of the drilling fluid collection device.

[0047] Please refer to Figure 2, the liquid discharge port 202 is connected to the first interface of the three-way joint through the return slurry pipeline 4. The second interface of the three-way joint is connected to the drilling fluid elevated tank, and the third interface of the three-way joint is connected to the blowout preventer.

[0048] It should be noted that during the drilling process, the drilling fluid will directly enter the blowout preventer from bottom to top. The drilling fluid entering the blowout preventer will flow to the drilling fluid elevated tank through the hydraulic flat valve and the three-way joint. The drilling fluid carried out by the drill pipe will drip onto the liquid collection cylinder 2, and the dripping drilling fluid will accumulate in the liquid collection cylinder 2. When the drilling fluid accumulates to a height level with the liquid discharge port 202, the drilling fluid dripping onto the liquid collection cylinder 2 will flow out from the liquid discharge port 202, flow through the three-way joint through the return slurry pipeline 4, and finally enter the drilling fluid elevated tank, so as to collect the dripping drilling fluid and improve the recycling rate of the drilling fluid at the same time.

[0049] In the above situation, the lifting device 3 is a hydraulic device. There are at least two hydraulic devices, and at least two hydraulic devices are evenly arranged in the circumferential direction of the outer sleeve 1. The hydraulic devices are all connected to the power source through an oil circuit, a hydraulic distributor is provided on the oil circuit, and a reversing valve is provided on the power source.

[0050] It can be understood that the hydraulic power is provided to the hydraulic device by the power source, the oil supply amount to the multiple hydraulic devices is controlled to be consistent by the hydraulic distributor, so that the multiple hydraulic devices can operate synchronously, and the flow direction of the oil in the oil circuit is controlled by the switching valve to realize the control of the lifting of the liquid collection cylinder 2, so as to realize the lifting movement of the drilling fluid collection device to meet the requirements of different installation heights.

[0051] Among them, in this embodiment, there are three hydraulic devices. However, in actual applications, there is no limitation on this, as long as the above technical effects can be achieved.

[0052] Please refer to Figure 2 and Figure 3 , the hydraulic device includes a hydraulic cylinder 31 and a hydraulic rod 32 movably arranged in the hydraulic cylinder 31. The hydraulic cylinder 31 is fixed to the outer sleeve 1, and the output end of the hydraulic rod 32 is hinged to the liquid collection cylinder 2. The hydraulic cylinder 31 is connected to the power source through an oil circuit.

[0053] It should be noted that the hydraulic power is provided to the multiple hydraulic devices by the hydraulic power source, and the hydraulic oil with the same pressure is distributed to the multiple hydraulic cylinders 31 by the hydraulic distributor, so that the hydraulic rods 32 in the multiple hydraulic cylinders 31 can extend or contract synchronously, thereby driving the liquid collection cylinder 2 to rise or fall stably.

[0054] In the above embodiment, at least two groups of installation structures for installing the hydraulic cylinder 31 are provided in the circumferential direction of the outer sleeve 1, and any group of installation structures includes two installation piles 5 arranged collinearly in the height direction of the outer sleeve 1.

[0055] It can be understood that the hydraulic cylinder 31 is fixed to the outer sleeve 1 through the mounting pile 5 to achieve the installation and fixation of the hydraulic cylinder 31 and the outer sleeve 1.

[0056] Among them, in this embodiment, three groups of installation structures are provided. However, in practical applications, there is no limitation on this, as long as the above technical effects can be achieved.

[0057] Please refer to Figure 4 , the liquid collection cylinder 2 includes an inner sleeve 21 that is sleeved in the outer sleeve 1 and can be lifted and a liquid collection cylinder 22 provided at the top of the inner sleeve 21. The liquid collection cylinder 22 has an inverted frustum structure. A hinge 6 is provided circumferentially at the top of the inner sleeve 21, and the hinge 6 is hinged to the output end of the hydraulic rod 32.

[0058] It should be noted that after the drill pipe brings out the drilling fluid, it drips onto the installation platform or directly onto the liquid collection cylinder 22. The drilling fluid flows into the inner sleeve 21 through the barrel wall of the liquid collection cylinder 22. When the drilling fluid accumulates in the inner sleeve 21 to a height flush with the liquid discharge port 202, the drilling fluid that drips or flows into the inner sleeve 21 will flow out from the liquid discharge port 202, flow through the reverse slurry pipeline 4 through the three-way joint, and finally enter the drilling fluid elevated tank, so as to collect the dripping drilling fluid.

[0059] Among them, setting the liquid collection cylinder 22 to an inverted frustum structure can collect the drilling fluid dripping from the drill pipe to the greatest extent. In practical applications, there is no limitation on this, as long as the above technical effects can be achieved.

[0060] In the above embodiment, a flange is provided circumferentially at the top end of the inner sleeve 21, and a flange is also provided circumferentially at the bottom end of the liquid collection cylinder 22. The inner sleeve 21 and the liquid collection cylinder 22 are connected by flanges and bolts, and the inner sleeve 21 and the liquid collection cylinder 22 are sealed by steel rings.

[0061] It can be understood that the inner sleeve 21 and the liquid collection cylinder 22 are connected by flanges and sealed by steel rings.

[0062] As a preferred implementation manner, an annular groove group 7 is provided on the outer periphery of the bottom of the inner sleeve 21, and sealing rings are provided in the annular groove group 7.

[0063] It should be noted that by providing the sealing rings, the inner sleeve 21 and the outer sleeve 1 are sealed.

[0064] Please refer to Figure 5 , the annular groove group 7 includes two first annular grooves 71 and one second annular groove 72. The first annular grooves 71 are provided on the upper and lower sides of the second annular groove 72. YX-type sealing rings 8 are provided in the first annular grooves 71, and O-type sealing rings 9 are provided in the second annular groove 72.

[0065] It can be understood that the sealing between the inner sleeve 21 and the outer sleeve 1 is achieved by setting the O-ring 9. By setting YX-type seals 8 on the upper and lower sides of the O-ring 9, the larger particles remaining on the inner wall of the outer sleeve 1 can be removed by the YX-type seals 8, so as to avoid the particles on the inner wall of the outer sleeve 1 from rubbing against the O-ring 9 and damaging the O-ring 9, thereby increasing the service life of the O-ring 9.

[0066] Among them, the installation directions of the two YX-type seals 8 are as Figure 4 shown, and the effect of scraping off the drilling fluid can be achieved. In practical applications, other methods can also be used to protect the O-ring 9, and no limitation is imposed on this.

[0067] Please refer to Figure 6 , the outer sleeve 1 is a cylindrical structure, and the bottom of the outer sleeve 1 has a tapered contraction structure with a flange provided on the outer periphery of the bottom end of the contraction structure.

[0068] It should be noted that the outer sleeve 1 and the blowout preventer at its bottom are connected by a flange and sealed with a steel ring.

[0069] In summary, for the liftable drilling fluid collection device provided by the present utility model, the height of the drilling fluid collection device can be adjusted arbitrarily within the upper and lower limits, which can meet the requirements of various installation heights, and greatly reduce the problems that the drilling fluid collection device cannot be installed or has poor collection effect due to the installation height.

[0070] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0071] Each embodiment in this specification is described in a progressive manner. The key points of each embodiment are the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0072] The above provides a detailed introduction to a liftable drilling fluid collection device provided by the present utility model. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and modifications can still be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. A liftable drilling fluid collection device, characterized in that, Comprising: An outer sleeve (1), which is a hollow structure, and the outer sleeve (1) is fixed to a blowout preventer; A liquid collecting cylinder (2), which is a hollow structure, the liquid collecting cylinder (2) is sleeved in the outer sleeve (1) in a liftable manner, a liquid inlet (201) for collecting drilling fluid is provided at the top of the liquid collecting cylinder (2), a liquid discharge port (202) is provided on the circumference of the liquid collecting cylinder (2), and the liquid discharge port (202) is arranged close to the liquid inlet (201); A lifting device (3) is arranged in the outer sleeve (1), and the output end of the lifting device (3) is connected to the liquid collecting cylinder (2) to drive the lifting movement of the liquid collecting cylinder (2).

2. The liftable drilling fluid collection device according to claim 1, wherein The liquid discharge port (202) is connected to the first interface of a three-way joint through a return slurry pipeline (4), the second interface of the three-way joint is connected to a drilling fluid elevated tank, and the third interface of the three-way joint is connected to the blowout preventer.

3. The liftable drilling fluid collection device according to claim 1, wherein The lifting device (3) is a hydraulic device, at least two hydraulic devices are provided, at least two hydraulic devices are evenly arranged in the circumferential direction of the outer sleeve (1), the hydraulic devices are all connected to a power source through an oil circuit, a hydraulic distributor is provided on the oil circuit, and a reversing valve is provided on the power source.

4. The liftable drilling fluid collection device according to claim 3, characterized in that The hydraulic device includes a hydraulic cylinder (31) and a hydraulic rod (32) movably arranged in the hydraulic cylinder (31), the hydraulic cylinder (31) is fixed to the outer sleeve (1), the output end of the hydraulic rod (32) is hinged to the liquid collecting cylinder (2), and the hydraulic cylinder (31) is connected to the power source through the oil circuit.

5. The liftable drilling fluid collection device according to claim 4, wherein At least two groups of mounting structures for mounting the hydraulic cylinder (31) are provided on the circumference of the outer sleeve (1), and any group of the mounting structures includes two mounting piles (5) arranged collinearly in the height direction of the outer sleeve (1).

6. The liftable drilling fluid collection device according to claim 5, wherein The liquid collecting cylinder (2) includes an inner sleeve (21) sleeved in the outer sleeve (1) in a liftable manner and a liquid collecting cylinder (22) arranged at the top of the inner sleeve (21), the liquid collecting cylinder (22) is of an inverted frustum structure, hinges (6) are provided on the circumference of the top of the inner sleeve (21), and the hinges (6) are hinged to the output ends of the hydraulic rods (32).

7. The liftable drilling fluid collection device according to claim 6, wherein, A flange is provided on the circumference of the top end of the inner sleeve (21), a flange is also provided on the circumference of the bottom end of the liquid collecting cylinder (22), the inner sleeve (21) and the liquid collecting cylinder (22) are connected through the flange and bolts, and the inner sleeve (21) and the liquid collecting cylinder (22) are sealed with a steel ring.

8. The liftable drilling fluid collection device according to claim 7, characterized in that, An annular groove group (7) is provided on the outer circumference of the bottom of the inner sleeve (21), and sealing rings are provided in the annular groove group (7).

9. The liftable drilling fluid collection device according to claim 8, wherein, The annular groove group (7) includes two first annular grooves (71) and one second annular groove (72), the first annular grooves (71) are arranged on the upper and lower sides of the second annular groove (72), YX-type sealing rings (8) are provided in the first annular grooves (71), and O-type sealing rings (9) are provided in the second annular groove (72).

10. The liftable drilling fluid collection device according to any one of claims 7-9, characterized in that, The outer sleeve (1) is of a cylindrical structure, the bottom of the outer sleeve (1) has an inverted frustum-shaped contraction structure, and a flange is provided on the outer circumference of the bottom end of the contraction structure.

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