Seals for safety joints for grooved steel pipes

Abstract

A seal for a safety joint for a grooved steel pipe includes a sealing rubber ring, wherein the sealing rubber ring includes an outer sealing structure and an inner sealing structure; the outer sealing structure is composed of an open oblique end face of the outer lip edge of the sealing rubber ring, an outer ring opening oblique edge and an outer convex circular ring, an outer ring, and a bottom; the inner sealing structure is composed of an inner lip of the inner lip edge of the sealing rubber ring and an inner convex truncated cone. The inner and outer seals of the sealing rubber ring of the present invention can effectively provide good sealing capabilities in low and high pressure states, whether in relatively flat areas or in outdoor environments. The two-way seal in the low-pressure state can still provide good sealing capabilities, especially in an uneven outdoor environment.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline connection of outdoor steel pipelines, and in particular relates to a sealing member of a safety joint for a grooved steel pipe. Background Art

[0002] The lip seal is an axial seal made of pure rubber, also known as an oil seal. The lip seal is fixed on the journal of the rotating shaft by relying on the tension of its body on the journal, and at the same time, the sealing pair formed by the bending performance of its lip and its pressing force on the seal is used to prevent water and impurities from entering the rotating lubricating seal body during the operation of the equipment, so as to meet the requirements of protecting the normal operation of the rotating shaft lubricating seal device. Sealing principle: First install it in the groove without external pressure, then the sealing lip is compressed by the piston rod or cylinder wall to produce an initial contact pressure. Under the action of external pressure, the sealing lip of the lip seal is pressed against the sealed surface, and the pressure is transmitted to the contact point through the gasket. The pressure at the lip edge contact point is always greater than the liquid pressure, thus preventing fluid leakage. The lip seal has a high sealing efficiency under both high and low pressures, and has a certain compensation effect on wear, and will not cause rapid leakage.

[0003] For pipelines that are frequently connected and disassembled in large quantities, the pipelines and connectors are frequently connected and disassembled. As the distance of oil pipelines is getting longer and longer, more and more connectors are needed to connect them, and the frequency of maintenance and replacement increases. With the complexity of military struggle, oil pipelines are required to adapt to both flat environments and outdoor mountainous and hilly environments, that is, they must adapt to both low-pressure liquid transportation and high-pressure liquid transportation.

[0004] The sealing rubber ring on the existing connection joint relies on the elasticity of rubber to achieve sealing. When the grooved steel pipe has a certain amount of relative angular displacement and corresponding axial deflection, leakage may occur. The adaptable pressure range is not wide. When there is no leakage at low pressure, the high pressure is unstable. After the high pressure is stable and there is no leakage, there is a slight leakage at low pressure. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a seal for a safety joint for a grooved steel pipe, so as to improve the pressure-bearing capacity of the safety joint for a grooved steel pipe, so as to meet the requirements of low-pressure without leakage, and to realize the ability to withstand higher pressures, and to adapt to both low and high pressures. The inner convex cone setting of the sealing rubber ring of the present invention can achieve good central insertion when the grooved steel pipe has a certain amount of relative angular displacement and corresponding axial deflection. The inner and outer seals of the sealing rubber ring can effectively provide good sealing capabilities in low and high pressure states, whether in relatively flat areas or in outdoor environments. The two-way seal in the low-pressure state can still have good sealing capabilities, especially in the uneven environment in the field.

[0006] The technical solution of the present invention is: it includes a sealing rubber ring, which includes an external sealing structure and an internal sealing structure; the external sealing structure is composed of an open oblique end face of the outer lip edge of the sealing rubber ring, an open oblique edge of the outer ring and an outer convex circular ring, an outer ring, and a bottom; the internal sealing structure is composed of an inner lip of the inner lip edge of the sealing rubber ring and an inner convex cone.

[0007] The outer lip edge of the sealing rubber ring, the bottom of the sealing rubber ring and the inner straight groove are interference fit to form an external seal; the bottom of the sealing rubber ring and the outer end of the inner straight groove, the opening oblique end surface and the inner end of the inner straight groove form a sealing pair, the bottom of the sealing rubber ring is tightly attached to the outer end of the inner straight groove, and the opening oblique end surface and the inner end of the inner straight groove are interference fit, the opening oblique end surface naturally becomes a straight surface, and the outer ring opening oblique edge is tightly attached to the inner diameter of the inner straight groove;

[0008] The inner lip of the inner lip edge of the sealing rubber ring contacts the outer diameter of the pipeline groove connecting steel pipe, and the inner convex truncated cone contacts the outer circular inclined surface of the groove pipe joint clamping ring to form an inner seal.

[0009] The root of the outer lip of the sealing rubber ring intersects with the root of the inner lip of the sealing rubber ring, and the front of the outer lip and the front of the inner lip are opened to form an open opening. The outer ring root of the outer lip has an outer convex circular ring, and the inner ring root of the inner lip has an inner convex cone; the cross-section of the sealing rubber ring is a polygonal structure, the bottom of the sealing rubber ring is a plane, the front of the outer ring of the outer lip of the sealing rubber ring is the outer ring opening bevel, and the front of the outer lip of the sealing rubber ring is an opening bevel end face.

[0010] Taking into account the ability to withstand high pressure during application, the sealing rubber ring of the present invention is provided with an inner convex cone, which plays a role of root support when subjected to high pressure. The two-sealing arrangement of the inner sealing and outer sealing structures of the sealing rubber ring can effectively provide good sealing capabilities in low and high pressure conditions, whether in relatively flat areas or outdoor environments, especially in outdoor uneven environments. The inner convex cone arrangement of the sealing rubber ring of the present invention can achieve good central insertion performance when the grooved steel pipe has a certain amount of relative angular displacement and corresponding axial deflection. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a usage state diagram of the present invention;

[0012] Figure 2 yes Figure 1 Middle M enlarged image;

[0013] Figure 3 It is a schematic diagram of the local structure of the connector body;

[0014] Figure 4 It is a schematic diagram of the structure of the sealing rubber ring;

[0015] Figure 5 yes Figure 4A magnified view of part N;

[0016] Figure 6 It is a schematic diagram of the use of the grooved steel pipe and the connector body 1 in a folded angle state. DETAILED DESCRIPTION

[0017] Figure 1-5 In the figure, the safety joint for grooved steel pipe consists of a connector body 1, a grooved pipe joint clamping ring 3, a steel locking ring 2, and a sealing rubber ring 4. The connector body 1 and the grooved pipe joint clamping ring should be made of 35Cr or thick-walled pipes of equal strength. The steel locking ring should be made of 65Mn cold-drawn spring steel wire. The sealing rubber ring 4 should be made of nitrile oil-resistant rubber or synthetic oil-resistant rubber. The outer surface hardness of the connector body 1 shall not be less than HRC28, and the surface hardness of the internal R3 arc shall not be less than HRC32. The surface hardness of the grooved pipe joint clamping ring 3 shall not be less than HRC28, and the surface hardness of the steel locking ring 2 shall not be less than HRC32. The steel locking ring 2 is a circular ring with a notch, and its inner diameter is slightly smaller than the outer diameter of the grooved pipe joint connecting the end of the steel pipe in the free state.

[0018] The middle part of the inner wall of the connector body 1 is a shoulder 206. The inner cavity of the connector body 1 on both sides of the shoulder 206 is a mounting hole for installing the pipeline groove connecting steel pipe 5. The mounting hole includes a second step hole 205 located on the inner side and a first main step hole 204 located on the outer side. The outer end of the first main step hole 204 is chamfered to form an inner hole bevel 208. The inner end of the first main step hole 204 is connected to the second step hole 205 through a transition arc bevel 207. The aperture of the first main step hole 204 is larger than the aperture of the second step hole 205. The hole wall of the first main step hole 204 is provided with an inner arc groove 203, an outer end straight groove 201, and an inner end straight groove 202 from the outside to the inside. The inner arc groove 203 is connected to the outer side of the notch of the outer end straight groove 201. The connector body 1 has an outer round bevel 209. The sealing rubber ring 4 is installed in the inner end straight groove 202, and the steel locking ring 2 is installed in the outer end straight groove 201.

[0019] When the pipeline groove connection steel pipe 5 is connected to the connector body 1 to form a pipeline for liquid transportation, the pipeline groove connection steel pipe is subjected to tension and liquid pressure. This force acts on the connector body 1 after passing through the outer arc groove 403 of the groove pipe joint clamp ring 3, the steel locking ring 2, and the inner arc groove 203 along the pipeline groove connection steel pipe. This force F acts on the outer end of the connector body 1 in a direction of about 45°. The outer arc groove 403 of the groove pipe joint clamp ring 3, the steel locking ring 2, and the inner arc groove 203 of the connector body form an arc surface fine-tuning mechanism, and the steel locking ring 2 cooperates with the inner / outer arc grooves to form a matching pair. The cross section of the steel locking ring is circular.

[0020] The sealing rubber ring 4 adopts lip seal, the sealing rubber ring 4 is a one-way seal, and the pressure direction is concave one-way (such as Figure 5The sealing rubber ring 4 is a Y-shaped ring-shaped sealing rubber ring with an inner convex cone, with an inner convex cone at the root, a Y-shaped ring cross section, and is made of rubber, which can withstand high pressure. The inner lip edge of the traditional Y-shaped sealing rubber ring is a bevel edge. Considering the improvement of the ability to withstand high pressure, the sealing rubber ring 4 is provided with an inner convex cone 301, which plays a role in supporting the root when it is subjected to high pressure.

[0021] The sealing rubber ring 4 is installed at the inner straight groove 202 in the connector body 1: the outer lip 306 cooperates with the inner straight groove 202, the outer ring 308, the outer convex ring 307, and the outer ring opening bevel 305 cooperate with the inner diameter of the inner straight groove 202, and the bottom 309 and the opening bevel end surface 304 tightly cooperate with the two ends of the inner straight groove 202 to play an external sealing role; the inner lip 303 is pressed tightly against the outer diameter cylindrical surface of the groove pipe joint at the end of the pipeline groove connecting steel pipe 5, and the inner lip 302 linearly cooperates with the outer diameter cylindrical surface of the groove pipe joint at the end of the pipeline groove connecting steel pipe 5, and the inner lip 302 cooperates with the outer diameter cylindrical surface of the groove pipe joint at the end of the pipeline groove connecting steel pipe, that is, the line contacts the cylindrical surface, and plays an internal sealing role. The outer diameter of the sealing rubber ring 4 is slightly larger than the inner diameter of the inner straight groove 202, and the inner diameter of the inner lip 302 is slightly smaller than the outer diameter of the pipeline groove connecting steel pipe 5.

[0022] The sealing functions of the sealing rubber ring 4 include: inner sealing and outer sealing.

[0023] ① The outer seal is formed by the open oblique end face 304 of the outer lip 306, the outer ring opening oblique edge 305, the outer convex ring 307, the outer ring 308, the bottom 309 and the inner diameter and both ends of the inner straight groove 202 to form a sealing pair. The bottom 309 of the sealing rubber ring 4 is in close contact with one end of the inner straight groove 202. After the open oblique end face 304 and the other end of the inner straight groove 202 are interference fitted, the open oblique end face 304 naturally becomes a straight surface, and the outer ring opening oblique edge 305 becomes an approximately straight edge and is in close contact with the inner diameter of the inner straight groove 202;

[0024] In the low-pressure state, the outer diameter of the sealing rubber ring 4 is slightly larger than the inner diameter of the inner straight groove 202. The outer ring opening bevel 305 and the outer convex ring 307 are elastically attached to the inner diameter of the inner straight groove 202 to form two seals, thereby overcoming low-pressure leakage and achieving sealing. In the high-pressure state, the rubber elastomer fills the inner diameter of the inner straight groove 202 under the action of liquid pressure to play a self-sealing role.

[0025] ② The inner seal is formed by the inner lip 302 of the inner lip edge 303 and the inner convex truncated cone 301 contacting the outer diameter of the pipeline groove connecting steel pipe 5 and the outer circular inclined surface 405 of the groove pipe joint clamping ring 3 respectively.

[0026] In the low-pressure state, the line of the inner lip 302 of the inner lip edge 303 and the outer diameter cylindrical surface of the groove pipe joint at the end of the pipeline groove connecting steel pipe 5 cooperate with two seals, thereby overcoming low-pressure leakage and achieving sealing. In the high-pressure state, the inner lip edge 303 and the inner convex cone 301 at its root are tightly attached to the outer diameter cylindrical surface of the groove pipe joint under the action of liquid pressure, playing a self-sealing role. At this time, it is in a theoretically correct matching state (i.e., a centered state), and the high-pressure seal also achieves the best sealing effect.

[0027] Figure 6 In the test pipeline, three safety joints 501 and two pipeline groove connecting steel pipes 5 are used to form a test pipeline. The two ends of the test pipeline are lifted to a height of h from the ground by a lifting rope 1 509 and a lifting rope 2 5010 to simulate the angled state of the test pipeline. The heights of the two ends of the test pipeline from the ground are h1 and h2, and the distances between the middle safety joint 501 and the safety joints on both sides are L1 and L2. When the pipeline groove connecting steel pipe 5 and the safety joint 501 in the pipeline are at a certain inclination (the use state is an uneven environment in the field, and the groove steel pipe has a certain amount of relative angular displacement and corresponding axial deflection), the inner lip edge 303 and the inner convex truncated cone 301 at its root play the main role of bearing large deformation and sealing.

[0028] The inner and outer seals of the sealing rubber ring 4 can effectively provide good sealing ability in low and high pressure states, whether in relatively flat areas or in outdoor environments. The two seals in the low-pressure state can still have good sealing ability, especially in the uneven environment in the wild.

Claims

1. A seal for a safety joint for a grooved steel pipe, characterized in that: It comprises a sealing rubber ring for sealing the outer diameter of a steel pipe connected by a pipeline groove, a groove pipe joint clamp and a connector body, and the sealing rubber ring comprises an outer sealing structure and an inner sealing structure; the outer sealing structure is composed of an opening oblique end face of an outer lip edge of the sealing rubber ring, an outer ring opening oblique edge and an outer convex circular ring, an outer ring and a bottom; the inner sealing structure is composed of an inner lip and an inner convex truncated cone of an inner lip edge of the sealing rubber ring; the root of the outer lip edge of the sealing rubber ring intersects with the root of the inner lip edge of the sealing rubber ring, the front of the outer lip edge opens with the front of the inner lip edge to form an opening, the outer ring root of the outer lip edge has an outer convex circular ring, and the inner ring root of the inner lip edge has an inner convex truncated cone; The outer seal is formed by the open beveled end face of the outer lip, the open beveled edge of the outer ring, the outer convex ring, the outer ring, the bottom and the inner diameter and both ends of the inner straight groove to form a sealing pair. The bottom of the sealing rubber ring is in close contact with one end of the inner straight groove of the connector body. After the open beveled end face and the other end of the inner straight groove are interference fitted, the open beveled end face naturally becomes a straight face, and the open beveled edge of the outer ring becomes an approximately straight edge and is in close contact with the inner diameter of the inner straight groove. In the low-pressure state, the outer diameter of the sealing rubber ring is slightly larger than the inner diameter of the inner straight groove. The outer ring opening bevel and the outer convex ring rubber elastic force are tightly attached to the inner diameter of the inner straight groove to form two seals. In the high-pressure state, the rubber elastic body is filled with the inner diameter of the inner straight groove by the liquid pressure to form a self-sealing effect. The inner seal is formed by the inner lip and the inner convex cone of the inner lip edge respectively contacting the outer diameter of the pipeline groove connecting steel pipe and the outer circle inclined surface of the groove pipe joint clamp ring; In the low-pressure state, the inner lip line of the inner lip edge and the outer diameter cylindrical surface of the groove pipe joint at the end of the pipeline groove connecting the steel pipe cooperate with two seals. In the high-pressure state, the inner lip edge and the inner convex cone at its root are tightly attached to the outer diameter cylindrical surface of the groove pipe joint by the liquid pressure, playing a self-sealing role; The inner convex cone of the sealing rubber ring is set to ensure that when the grooved steel pipe has a certain amount of relative angular displacement and corresponding axial deflection, it still has good central insertion performance.

2. The seal of the safety joint for grooved steel pipe according to claim 1, characterized in that: The outer lip edge of the sealing rubber ring, the bottom of the sealing rubber ring and the inner straight groove are interference fit to form an external seal; the bottom of the sealing rubber ring and the outer end of the inner straight groove, the opening oblique end surface and the inner end of the inner straight groove form a sealing pair, the bottom of the sealing rubber ring is tightly attached to the outer end of the inner straight groove, and the opening oblique end surface and the inner end of the inner straight groove are interference fit, the opening oblique end surface naturally becomes a straight surface, and the outer ring opening oblique edge is tightly attached to the inner diameter of the inner straight groove; The inner lip of the inner lip edge of the sealing rubber ring contacts the outer diameter of the pipeline groove connecting steel pipe, and the inner convex truncated cone contacts the outer circular inclined surface of the groove pipe joint clamping ring to form an inner seal.

3. The seal of the safety joint for grooved steel pipe according to claim 1, characterized in that: The cross section of the sealing rubber ring is a polygonal structure, the bottom of the sealing rubber ring is a plane, the front part of the outer ring of the outer lip of the sealing rubber ring is the outer ring opening bevel, and the front of the outer lip of the sealing rubber ring is an open bevel end face.

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