A stop ring for oil casing

Abstract

The utility model discloses a kind of stop ring for petroleum casing, including connecting ring, fastening outer ring and fastening inner ring, the outer surface of the connecting ring is equipped with outer thread, the inner surface middle section of the fastening outer ring is equipped with inner conical surface, the both ends of the inner conical surface are connected with large diameter section and small diameter section respectively, and inner thread is equipped in large diameter section, the outer surface of the fastening inner ring is cylindrical and the front end is circular arc surface, there is a break on the circumference of the fastening inner ring, and the inner surface perimeter of fastening inner ring is less than the outer surface perimeter of petroleum casing to form the gap gap for fastening inner ring contraction at the break, the inner surface of the fastening inner ring is equipped with multiple annular cutting edges at intervals. The utility model's fastening outer ring and fastening inner ring are extruded by circular arc surface and inner conical surface cooperation, fastening inner ring is extruded and shows a tendency of forward inclination, front annular cutting edge is cut into petroleum casing first, and the rest cutting edge is gradually cut in with stress increasing, without exerting too large torque, installation is more convenient.

Description

Technical Field

[0001] This utility model belongs to the technical field of oil drilling and cementing equipment, and particularly relates to a stop ring for oil casing. Background Technology

[0002] During oil extraction, oil casing needs to be inserted deep into the well. The stop ring, as a crucial component of the oil casing, is used to limit the axial displacement of the casing and ensure the stability of the casing installation. Existing oil casing stop rings consist of an inner ring with a cutting edge on the inside and threads on the outside, and an outer ring with threads on the inside. The outer surface of the inner ring and the inner surface of the outer ring are conical. When the inner and outer rings are tightened by the threads, the inner ring contracts and deforms under the pressure of the inclined plane, and the inner cutting edge cuts into the oil casing to achieve stopping.

[0003] Due to structural limitations, existing retaining rings have the following problems and drawbacks: 1. Installation is relatively difficult. The inner and outer rings are pressed against each other by the conical surfaces. All the cutting edges of the inner ring need to cut into the oil casing at the same time. A large torque needs to be applied to both the inner and outer rings at the same time to tighten the threads of the inner and outer rings. 2. The inner ring has a cutting edge on the inner side and a thread on the outer side, making its structure relatively complex and difficult to machine; 3. After installation, disassembly is difficult when it is necessary, which is not conducive to secondary use; 4. The cutting edge for cutting into oil casing is small, but in order to achieve the purpose of cutting, the hardness of the cutting edge needs to be guaranteed. This results in the cutting edge having high hardness despite its small size, which can easily cause damage. Utility Model Content

[0004] In view of the problems existing in the prior art, the purpose of this utility model is to provide a stop ring for oil casing.

[0005] To solve the above problems, the present invention adopts the following technical solution: A retaining ring for oil casing includes a connecting ring, a fastening outer ring, and a fastening inner ring. The outer surface of the connecting ring has external threads. The middle section of the inner surface of the fastening outer ring has an inner conical surface. The two ends of the inner conical surface are respectively connected to a large-diameter section and a small-diameter section. The large-diameter section has internal threads. The outer surface of the fastening inner ring is cylindrical and the front end is an arc surface. There is a break on the circumference of the fastening inner ring, and the circumference of the inner surface of the fastening inner ring is smaller than the circumference of the outer surface of the oil casing, thus forming a clearance notch for the contraction of the fastening inner ring at the break. The inner surface of the fastening inner ring has multiple annular cutting edges spaced apart. The fastening outer ring is fastened by the threaded engagement of its internal threads with the external threads of the connecting ring. The fastening inner ring is connected between the connecting ring and the fastening outer ring, with its rear end sidewall abutting against the end of the connecting ring and its front arc surface abutting against the inner conical surface.

[0006] Preferably, a plurality of wrench mounting holes are provided at intervals on the circumference of the outer surface of the fastening outer ring.

[0007] Preferably, the outer fastening ring has a threaded through hole penetrating the side wall of the outer fastening ring at the small diameter section for installing a set screw.

[0008] Preferably, the root of the connection between the annular cutting edge and the inner surface of the fastening inner ring is a rounded transition connection.

[0009] Preferably, the inner fastening ring is provided with a wrench hole on each side of the clearance notch.

[0010] Preferably, when the inner ring is not subjected to external force, its inner diameter is smaller than the outer diameter of the oil casing.

[0011] Preferably, there are two outer fastening rings and two inner fastening rings, which are connected to the two ends of the connecting ring respectively.

[0012] Preferably, the outer surface end of the connecting ring is chamfered.

[0013] The beneficial effects of this utility model are: Compared with existing technologies, the advantages of this utility model are: 1. The outer and inner rings are pressed together by the arc surface and the inner conical surface. When the inner ring is pressed, it tends to tilt forward. The front annular cutting edge first cuts into the oil casing, and the other cutting edges gradually cut in as the force increases. No excessive torque is required, making installation more convenient. 2. The connecting ring and the inner fastening ring are designed as separate units. The outer surface of the connecting ring is provided with external threads, and the inner surface of the inner fastening ring is provided with an annular cutting edge. The functions of the two are separated, which makes it easy to process them separately and reduces the processing difficulty. 3. The inner ring is provided with wrench locking holes on both sides of the clearance notch. When disassembling, the wrench can be inserted into the locking hole and force applied in the opposite direction to separate the inner ring from the notch and expand its diameter, making it easy to detach from the oil casing. This makes disassembly convenient and facilitates secondary use. 4. The root of the connection between the annular cutting edge and the inner surface of the fastening inner ring is connected with a rounded corner to avoid stress concentration. This not only ensures the hardness of the cutting edge but also improves its strength and reduces the risk of damage. Attached Figure Description

[0014] Figure 1 This is an exploded view of the components of this utility model; Figure 2 A partially enlarged sectional view of this utility model before the inner ring is cut into the oil casing for securing the inner ring; Figure 3 A partially enlarged cross-sectional view of this utility model as the inner ring is gradually cut into the oil casing to secure it; Figure 4This is a cross-sectional view of the present invention, which has two outer fastening rings, an inner fastening ring, and a connecting ring, and is installed as a bidirectional stop ring on an oil casing.

[0015] In the diagram: 1. Connecting ring; 101. External thread; 2. Fastening outer ring; 201. Inner conical surface; 202. Internal thread; 203. Wrench mounting hole; 204. Threaded through hole; 3. Fastening inner ring; 301. Arc surface; 302. Displacement notch; 303. Annular cutting edge; 304. Wrench locking hole; 4. Oil casing; 5. Set screw. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] like Figure 1-4 As shown, this utility model provides a technical solution: a stop ring for oil casing, including a connecting ring 1, a fastening outer ring 2, and a fastening inner ring 3. The outer surface of the connecting ring 1 is provided with an external thread 101. The middle section of the inner surface of the fastening outer ring 2 is provided with an inner conical surface 201. The two ends of the inner conical surface 201 are respectively connected to a large-diameter section and a small-diameter section. The large-diameter section is provided with an internal thread 202. The outer surface of the fastening inner ring 3 is cylindrical and the front end is an arc surface 301. There is a break on the circumference of the fastening inner ring 3. Furthermore, the circumference of the inner surface of the inner fastening ring 3 is smaller than the circumference of the outer surface of the oil casing 4, thus forming a clearance notch 302 at the break point for the contraction of the inner fastening ring 3. The inner surface of the inner fastening ring 3 is provided with multiple annular cutting edges 303 at intervals. The outer fastening ring 2 is fastened by the thread engagement between the inner thread 202 and the outer thread 101 of the connecting ring 1. The inner fastening ring 3 is connected between the connecting ring 1 and the outer fastening ring 2, with its rear end sidewall abutting against the end of the connecting ring 1 and its front end arc surface 301 abutting against the inner conical surface 201.

[0018] When using this utility model, such as Figure 2 , 3As shown, the outer fastening ring 2, the inner fastening ring 3, and the connecting ring 1 are sequentially fitted onto the oil casing 4, so that the rear end sidewall of the inner fastening ring 3 abuts against the end of the connecting ring 1. Then, the outer fastening ring 2 is initially connected to the outer thread 101 of the connecting ring 1 through the internal thread 202. The outer fastening ring 2 is rotated to advance along the outer thread 101 of the connecting ring 1. The inner conical surface 201 of the outer fastening ring 2 gradually squeezes the front arc surface 301 of the inner fastening ring 3, forcing the inner fastening ring 3 to move along the clearance notch. When the opening 302 contracts inward, since the inner ring 3 and the outer ring 2 are in contact with the arc surface 301 and the inner conical surface 201, the inner ring 3 tends to tilt forward when it is squeezed. The front annular cutting edge 303 first cuts into the outer wall of the oil casing 4. As the force gradually increases, the other annular cutting edges 303 gradually cut in. When the outer ring 2 rotates to the point where it can no longer move, it stops rotating. At this time, the annular cutting edges 303 are tightly engaged on the oil casing 4, achieving axial stop.

[0019] In this invention, the outer ring 2 and the inner ring 3 are fastened by the interlocking of an arc surface 301 and an inner conical surface 201. The inner ring 3 exhibits a forward tilting tendency, with the front annular cutting edge 303 first cutting into the outer wall of the oil casing 4. As the force gradually increases, the other annular cutting edges 303 gradually cut in, without requiring a large torque. This solves the problem of existing retaining rings where the inner and outer rings are interlocked by conical surfaces, requiring all cutting edges of the inner ring to simultaneously cut into the oil casing, and necessitating the application of a large torque to both the inner and outer rings to fasten the threads. Furthermore, the fastening inner ring 3 and the connecting ring 1 of this utility model are set separately, dividing the original inner ring into two parts. The inner surface of the fastening inner ring 3 is provided with an annular cutting edge 303 for cutting and stopping, and the outer surface of the connecting ring 1 is provided with an external thread 101 for connecting and fastening the outer ring 2. The functions of the two are separated, which makes it easier to process them separately and solves the problem of the high processing difficulty of the existing inner ring. Moreover, the fastening inner ring 3 of this utility model has only one clearance notch 302, and the annular cutting edge 303 cuts into the oil casing 4 more on the circumference, providing greater stopping force.

[0020] Furthermore, such as Figure 4 As shown, two outer fastening rings 2 and two inner fastening rings 3 are provided, connected to the two ends of the connecting ring 1 respectively, thereby achieving bidirectional stopping of the oil casing 4 and expanding its applicability. For ease of tightening, several wrench mounting holes 203 are spaced apart on the outer circumference of the outer surface of the outer fastening ring 2. During tightening, two half-moon wrenches can be used to rotate in opposite directions at the wrench mounting holes 203 of the two outer fastening rings 2, causing the two outer fastening rings 2 to move closer together on the connecting ring 1, thus achieving tightening. When only one outer fastening ring 2 and one inner fastening ring 3 are installed for stopping, wrench mounting holes can be provided on the outer surface of the connecting ring 1 to facilitate tightening of the outer fastening ring 2 and the connecting ring 1 using a half-moon wrench.

[0021] Furthermore, the outer ring 2 is provided with a threaded through hole 204 that penetrates the side wall of the outer ring 2 at the small diameter section for installing the set screw 5, which can effectively prevent the outer ring 2 from loosening after it is tightened with the connecting ring 1.

[0022] Furthermore, the root of the connection between the annular cutting edge 303 and the inner surface of the fastening inner ring 3 is a rounded transition connection to avoid stress concentration. While ensuring high hardness, this ensures the strength of the cutting edge and avoids damage to the cutting edge.

[0023] Furthermore, the inner fastening ring 3 is provided with a wrench hole 304 on each side of the relief notch 302. When it is necessary to remove the stop ring, first remove the outer fastening ring 2 and the connecting ring 1, and then insert two wrenches into the two wrench holes 304 respectively and apply force in opposite directions to separate the inner fastening ring 3 from the relief notch 302 to expand its diameter, thereby detaching it from the surface of the oil casing 4 for easy disassembly.

[0024] Furthermore, when the inner ring 3 is not subjected to external force, its inner diameter is smaller than that of the oil casing 4. During installation, two wrenches are inserted into the two wrench holes 304 respectively and applied in opposite directions to separate the inner ring 3 from the clearance notch 302, thus expanding its diameter. The inner ring 3 is then placed on the designated position on the oil casing 4. After installation, there is no gap between the inner ring 3 and the oil casing 4. When the outer ring 2 and the connecting ring 1 are tightened by their threads to compress the inner ring 3, the inner ring 3 can directly cut into the oil casing 4. This avoids the problem of excessive tightening stroke between the outer ring 2 and the connecting ring 1 when there is a gap, as the outer ring 2 and the connecting ring 1 first compress the inner ring 3 to shrink it to fit tightly against the oil casing 4 before gradually cutting into the oil casing 4.

[0025] Furthermore, the outer surface end of the connecting ring 1 is chamfered to facilitate the connecting ring 1 entering the fastening outer ring 2 and achieving accurate docking.

[0026] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A retaining ring for oil casing, characterized in that, The device includes a connecting ring (1), a fastening outer ring (2), and a fastening inner ring (3). The outer surface of the connecting ring (1) is provided with an external thread (101). The middle section of the inner surface of the fastening outer ring (2) is provided with an inner conical surface (201). The two ends of the inner conical surface (201) are respectively connected to a large-diameter section and a small-diameter section. The large-diameter section is provided with an internal thread (202). The outer surface of the fastening inner ring (3) is cylindrical and the front end is an arc surface (301). There is a break on the circumference of the fastening inner ring (3), and the circumference of the inner surface of the fastening inner ring (3) is smaller than that of the oil sleeve. The outer surface circumference of the tube (4) forms a clearance notch (302) at the break for the contraction of the inner ring (3). The inner surface of the inner ring (3) is provided with multiple annular cutting edges (303) at intervals. The outer ring (2) is fastened by the thread engagement of the inner thread (202) with the outer thread (101) of the connecting ring (1). The inner ring (3) is connected between the connecting ring (1) and the outer ring (2). Its rear end sidewall abuts against the end of the connecting ring (1), and its front end arc surface (301) abuts against the inner conical surface (201).

2. The retaining ring for oil casing according to claim 1, characterized in that, The outer surface of the fastening outer ring (2) is provided with a number of wrench mounting holes (203) at intervals.

3. A retaining ring for oil casing according to claim 1, characterized in that, The fastening outer ring (2) has a threaded through hole (204) at the small diameter section for installing the set screw (5).

4. A retaining ring for oil casing according to claim 1, characterized in that, The root of the connection between the annular cutting edge (303) and the inner surface of the fastening inner ring (3) is a rounded transition connection.

5. A retaining ring for oil casing according to claim 1, characterized in that, The inner fastening ring (3) is provided with a wrench hole (304) on both sides of the clearance notch (302).

6. A retaining ring for oil casing according to claim 1, characterized in that, When the inner ring (3) is not subjected to external force, its inner diameter is smaller than that of the outer diameter of the oil casing (4).

7. A retaining ring for oil casing according to claim 1, characterized in that, Two outer fastening rings (2) and two inner fastening rings (3) are provided, which are connected to the two ends of the connecting ring (1) respectively.

8. A retaining ring for oil casing according to claim 1, characterized in that, The outer surface end of the connecting ring (1) is chamfered.

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