CN217874630U - Long-distance natural gas pipeline pipe and long-distance natural gas conveying system - Google Patents

Abstract

The utility model discloses a pipe for long-distance natural gas pipeline and a long-distance natural gas transportation system, wherein the pipe for long-distance natural gas pipeline comprises a pipe body with a socket end and a socket end adapted to the socket end; There is a sealing rubber ring installation structure for placing the sealing rubber ring, and the pipe body is a ductile iron pipe. The isotropy, air tightness, consistency and corrosion resistance of the long-distance natural gas pipeline pipe of the utility model are all better than steel pipes, and the connection process of the pipeline formed by using it does not need to use solder, and the quality of the weld seam is eliminated. The inspection process greatly improves the service life of the pipeline while reducing the operating cost of the pipeline, and ensures the stability of the quality of the pipeline; moreover, the pipeline formed by the socket-type flexible seal connection can absorb certain axial expansion and diameter It is a long-distance natural gas pipeline with stable performance, long service life, high production and installation efficiency, and low operation and maintenance costs.

Description

Pipes for long-distance natural gas pipelines and long-distance natural gas transmission systems

technical field

The utility model relates to the technical field of long-distance natural gas pipelines, in particular to a pipe for long-distance natural gas pipelines and a long-distance natural gas delivery system.

Background technique

At present, long-distance natural gas pipelines generally need to be connected by welding. However, connecting pipelines by welding will have the following problems:

Due to the high price of solder, and after welding, not only the stress relief and anti-corrosion treatment of the weld seam, but also the quality inspection of the weld seam are required, resulting in long construction period and high cost.

At the same time, compared with the pipe body, the strength and corrosion resistance of the weld seam are reduced, which shortens the maintenance period of the long-distance natural gas pipeline.

In addition, since the welding process often needs to rely on the manual operation of the welders, the quality of the welds will fluctuate and the quality of the welds will be unstable. As a result, long-distance natural gas pipelines will fail due to natural gas leakage if they are not inspected and maintained in time during the maintenance period. Cause serious secondary disasters such as explosions and fires.

Utility model content

One of the objectives of the present utility model is to provide a long-distance natural gas pipeline pipe with high production efficiency, low cost, good quality and stability, so as to solve at least one of the above technical problems.

The pipe for long-distance natural gas pipelines includes a pipe body with a socket end and a straight pipe section, the socket end is located at one end of the pipe body, and the end of the straight pipe section away from the socket end is a socket end adapted to the socket end; wherein , the inner wall of the socket end is provided with a sealing rubber ring installation structure for placing the sealing rubber ring; the pipe body is a ductile iron pipe.

When installing the long-distance natural gas pipeline of the utility model, the sealing rubber ring is first placed in the sealing rubber ring installation structure, and then the pipe body of the adjacent long-distance natural gas pipeline passes through the socket end of one of the pipe bodies. The socket-type flexible sealing connection is completed by inserting the sealing rubber ring in the sealing rubber ring installation structure of the socket end of the other pipe body to form a long-distance natural gas pipeline. This flexible sealing connection method makes the long-distance natural gas pipeline It can absorb a certain amount of axial expansion and contraction, so it can resist the destructive force of geological disasters such as earthquakes and land subsidence, and keep the pipeline intact.

Since there is no need to use welding to connect adjacent pipe bodies, there is no need to carry out post-processing procedures such as pressure testing, anti-corrosion treatment of weld seams, quality inspection, and welding stress relief after subsequent on-site installation of pipe bodies, which greatly shortens the construction period. , The on-site installation and construction speed is 6-7 times faster than that of steel pipes, and the cost of installation, operation and maintenance of the pipe body is reduced by 20%-30%, and there will be no leakage due to weld failure during use.

When the pipeline steel pipe is used as the long-distance natural gas pipeline, since the pipe steel pipe is welded by rolling the steel plate after crimping, the steel plate will form fibrous crystals in the longitudinal direction when the steel plate is rolled, causing the longitudinal and transverse fracture of the steel plate There are differences in strength, especially when there are inclusions between transverse fibrous crystals, it will further reduce the transverse strength of the steel plate. In addition, the corrosion resistance of steel is poor, and natural gas contains a small amount of corrosive media such as _H2S and _CO2 . When these corrosive media meet water, they form acid and react with steel pipes to produce hydrogen atoms that enter the steel, and along some segregation The phase interface of the tissue expands. Once the hydrogen atoms combine into _H2 molecules, a hydrogen pressure of about 300MPa can be generated, causing cracks along the rolling direction, and the phenomenon of tearing large cracks in the pipeline steel pipe instantly. This is "hydrogen induced cracking" (HIC) and sulfide stress corrosion cracking (SCC). This kind of stress corrosion cracking has no obvious signs, and it is easy to cause sudden catastrophic accidents. And because the long-distance natural gas pipeline pipe of the present utility model is a ductile iron pipe, it has mechanical strength isotropy and strong corrosion resistance (particularly to H ₂ S and _CO Formed weak acid corrosion medium tolerance is very strong ), good air tightness, and good quality consistency of materials. The service life, safety, reliability, and cost performance of the pipeline are all superior to the current pipeline steel pipes. Not only the service life is several times higher than that of pipeline steel pipes, And during use, "hydrogen-induced cracking" (HIC) and sulfide stress corrosion cracking (SCC) will not occur like pipeline steel pipes, and the performance of the pipe body is more stable.

In some embodiments, the dimensional accuracy of the socket end is not less than ±0.2 mm; and/or the surface roughness Ra of the sealing working surface of the socket end and the sealing working surface of the socket end are both≯3.2 μm.

Since the dimensional accuracy of the socket end is not less than ±0.2mm, when the socket end is inserted into the sealing rubber ring in the sealing rubber ring installation structure of the socket end of the adjacent pipe body for socket connection, the relative swing between the two is not large. Guarantee the smooth progress of the socket connection; at the same time, due to the flexible socket connection of adjacent pipe bodies, the sealing rubber ring is mainly connected to the sealing working surface of the socket end (that is, the sealing working surface of the sealing rubber ring installation structure) and the corresponding socket end. The sealing working surfaces are in contact, and the surface roughness Ra of the two sealing working surfaces is controlled at ≯3.2μm, which can improve the tightness of the pipe connection, and can be inflated with 15MPa high-pressure gas for pressure test and tightness test for more than 24 hours No pressure drop, to ensure that the long-distance natural gas pipeline can transport natural gas with a pressure of 8MPa-12MPa (because the pressure of the tightness test is not lower than 1.10-1.25 times the pressure after the product is installed), without the risk of leakage.

In some embodiments, the inner wall of the pipe body is provided with at least one of the drag-reducing coating and the drag-reducing anti-corrosion coating; or the inner wall of the pipe body is provided with both the drag-reducing coating and the drag-reducing anti-corrosion coating At least one of them, and the outer wall of the pipe body is provided with an anti-corrosion coating. Therefore, while improving the anti-corrosion ability of the pipe body, the flow rate of the pipe body can be increased by reducing the resistance of the fluid flow, and the pressure drop of the fluid transported by the pipe body can be reduced, thereby reducing the cost of the pressurization station installed when transporting natural gas. Quantity, reduce operating costs.

Preferably, the thickness of the drag-reducing coating or the drag-reducing anti-corrosion coating is not less than 200 μm; the thickness of the anti-corrosion coating is not less than 70 μm. In order to avoid the coating from falling off due to wear and tear.

In some embodiments, the material grade of the ductile iron pipe for long-distance natural gas pipeline is either of the two ferrite matrix ductile iron materials QT400-18L and QT350-22L, or the material grade is QT450-18, QT500 Any of the three solid solution strengthened ferrite matrix ductile iron materials -14 and QT600-10. Therefore, ductile iron pipes of suitable materials can be used according to different use environments and special requirements of users.

In some embodiments, the installation structure of the sealing rubber ring is a stepped annular groove; the stepped annular groove includes a first annular groove for accommodating the working section of the sealing rubber ring on the inner wall of the socket end and a first annular groove for accommodating the sealing rubber The second annular groove of the hook of the ring, the first annular groove and the second annular groove communicate with each other, the depth of the second annular groove is greater than the depth of the first annular groove; the sealing working surface of the socket end includes at least the groove bottom of the first annular groove .

The main purpose of setting the sealing rubber ring installation structure into a stepped annular groove is to install a stepped sealing rubber ring therein. One end of the step-shaped sealing rubber ring extends radially outwards to form a protrusion (that is, the hook of the sealing rubber ring), and the part of the sealing rubber ring in the axial direction except the hook is the working section of the sealing rubber ring. When installing the sealing rubber ring, place the hook of the sealing rubber ring in the second annular groove, and place the working section of the sealing rubber ring in the first annular groove. Therefore, the sealing rubber ring installed in the stepped annular groove is not easy to come out of it, and the safety and stability are high.

In some embodiments, the inner wall of the socket end of the pipe body is provided with a guide section, a load-bearing section, and an allowance for making the pipeline formed by the pipe based on the long-distance natural gas pipeline have axial expansion and radial deflection. At least one of the three grooves.

By forming the guide section on the inner wall of the socket end, when the adjacent long-distance natural gas pipeline is connected with the pipe socket, it can provide a guiding function for the socket end to be inserted into the socket of the socket end, so as to ensure the smooth progress of the socket connection. Exemplarily, the guide section is arranged on the inner wall of the opening of the inner hole of the socket end of the pipe body, so that the socket end can be more easily inserted into the inner hole of the socket end when the adjacent pipe bodies are socket-connected. As one of the embodiments of the guide section, the guide section is a chamfer structure in which the inner diameter of the inner hole of the socket end gradually decreases from the outside to the inside.

By forming a load-bearing section on the inner wall of the socket end, the socket end can be supported by the load-bearing section below the socket end at the socket connection, avoiding the sealing rubber ring clamped between the socket end and the socket end at the socket The part below the end is overpressured by the self-weight of the tube body, resulting in uneven sealing effect from top to bottom.

In some embodiments, the guide section is set so that the one-sided fit gap between the socket end inserted into the corresponding socket end and the minimum diameter of the guide section is not greater than 2mm; the load-bearing section is set so that the socket end inserted into the corresponding socket end The matching gap with the load-bearing section is not greater than the matching gap with the smallest diameter of the guide section. Preferably, the one-side matching gap between the minimum diameter of the guide segment and the socket end inserted into the corresponding socket end is between 1mm and 2mm.

Preferably, the accommodating groove is set so that the long-distance natural gas pipeline is connected with a pipe socket to have a deflection angle not greater than 4°. Exemplarily, the accommodating groove capable of enabling long-distance natural gas pipelines to be connected with pipe sockets to have a deflection angle is implemented as a groove-shaped structure with an inner diameter larger than an outer diameter of the socket end. More preferably, allow the inner diameter of the groove to gradually increase from the side close to the socket end to the side close to the socket end; and/or allow the sidewall of the end of the groove away from the socket end from the bottom of the groove to the top It is inclined to the side away from the socket end, so as to ensure that the connected pipe has a deflection angle that meets the requirements, and at the same time reduce the processing allowance of the allowance groove, so as to improve the production effect, or avoid The wall thickness of the socket end is too thin to ensure the strength of the socket end.

In some embodiments, the pipe for long-distance natural gas pipelines further includes a sealing rubber ring fitted in the stepped annular groove. Preferably, the sealing rubber ring includes a working section and a fixing section with a hook, and at least part of the cross section of the free end of the working section is in a "V" shape, so that the socket end and the socket end of the socket connection can carry out the sealing of the sealing rubber ring. compression. Further, the second annular groove is located on the side of the first annular groove facing the socket end, and the "V"-shaped opening is set toward the side where the socket end is located. This arrangement will not insert the corresponding socket end into the socket end. Increase the barrier in the sealing rubber ring inside the mouth port.

In particular, the inner diameter of the inner working surface of the sealing rubber ring gradually decreases from the free end of the fixed section to the free end of the working section. When the adjacent pipe bodies are socketed and connected, the socket end inserted into the sealing rubber ring placed at the socket end increases with the depth of its insertion into the socket end, and the compression amount of the socket end to the sealing rubber ring gradually increases, and the sealant The tightness of the ring is gradually improved, thereby improving the tightness of the socket-type flexible sealing connection without increasing the difficulty of inserting the socket end.

In some embodiments, the sealing rubber ring is an oil-resistant sealing rubber ring.

According to another aspect of the utility model, a high-quality and stable long-distance natural gas transportation system is provided. The long-distance natural gas transmission system includes at least two aforementioned long-distance natural gas pipeline pipes; wherein, the outer surface of the spigot end of one of the two adjacent pipe bodies abuts against the outer surface of the other pipe body. The inner working surface of the sealing rubber ring in the sealing rubber ring installation structure in the socket end, so as to press the outer working surface of the sealing rubber ring on the sealing working surface of the sealing rubber ring installation structure where it is located.

Since the pipe body is a ductile iron pipe, there will be no problems such as HIC and SCC that often occur in pipeline steel pipes, and the ductile iron pipe not only has more stable performance, but also has better air tightness; at the same time, because the connection method of adjacent pipe bodies is The socket-type sealed connection, while increasing the construction speed, does not need to carry out post-processing procedures such as pressure test, anti-corrosion treatment of weld seam, quality inspection, and welding stress relief after the subsequent on-site installation of the pipe body. The cost of operation and maintenance is reduced by 20% to 30%. In addition, the long-distance natural gas transmission system obtained by the socket-type flexible sealing connection can absorb certain axial expansion and radial deflection, so it can resist earthquakes and ground subsidence, etc. The destructive power of geological disasters.

In some embodiments, there is a gap between the end of the socket end inserted into the corresponding socket end and the side wall of the corresponding receiving groove. Thus, the gas in the connected pipeline can pass through the gap, as well as the gap between the socket end of the connection and the bottom wall of the accommodation groove, and exert pressure on the surface of the "V"-shaped opening of the sealing rubber ring The sealing effect of the sealing rubber ring is improved by increasing the pressure of the inner and outer sealing working surfaces of the sealing rubber ring and the sealing working surfaces of the socket end and the sealing working surface of the socket end at the joint.

Description of drawings

Fig. 1 is a schematic cross-sectional structure diagram of a long-distance natural gas pipeline pipe according to an embodiment of the present invention;

Fig. 2 is a schematic cross-sectional structure diagram of a long-distance natural gas pipeline with a sealing rubber ring placed in an embodiment of the present invention;

Fig. 3 is the schematic diagram of the enlarged structure at A of the long-distance natural gas pipeline pipe shown in Fig. 2;

Fig. 4 is a schematic cross-sectional structure diagram of a long-distance natural gas transportation system according to an embodiment of the present invention;

Reference signs: 20, pipe body; 21, socket end; 22, socket end; 23, sealing rubber ring installation structure; 231, first annular groove; 232, second annular groove; 24, sealing rubber ring; 241, Fixed section; 2411, hook; 242, working section; 243, outer working surface; 244, inner working surface; 201, guide section; 202, tolerance groove; 203, bearing section.

Detailed ways

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

It should also be noted that in this article, the terms "comprising" and "comprising" not only include those elements, but also include other elements that are not explicitly listed, or also include the elements included in the process, method, article or equipment. inherent elements. Without further limitations, an element defined by the statement "comprising..." does not exclude the presence of additional same elements in the process, method, article or device comprising said element. The terms used herein are generally commonly used terms by those skilled in the art. If there is any inconsistency with commonly used terms, the terms herein shall prevail.

It should be noted that, the nodular cast iron rough pipe or nodular cast iron pipe mentioned in the embodiment of the utility model includes a socket end and a straight pipe section, wherein the inner diameter of the socket end is larger than the outer diameter of the straight pipe section, and the straight pipe section The free end is the socket end.

In the present utility model, when the pipeline formed based on the connection of the long-distance natural gas pipeline with the pipe socket is subjected to an external force, the adjacent pipe bodies 20 in the pipeline can undergo relative displacement along its axial direction, so that the pipeline has a certain displacement along the axial direction. The amount of expansion and contraction, that is, the pipe can absorb axial expansion and contraction.

In order to make the purpose, technical solutions and advantages of the embodiments of the utility model more clear, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described The embodiments are some embodiments of the present utility model, but not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Fig. 1 schematically shows a long-distance natural gas pipeline according to an embodiment of the present invention.

1, the long-distance natural gas pipeline includes a pipe body 20, which is a ductile iron pipe. The pipe body 20 includes an integrally formed or processed socket end 21 and a straight pipe section. The socket end 21 is located at the end of the pipe body 20. One end, the remaining part of the pipe body 20 except the socket end 21 is a straight pipe section, and the end of the straight pipe section away from the socket end 21 is a socket end 22, and the socket end 22 is adapted to the socket end 21, that is, the socket The end 22 can be inserted into the inner hole of the bell end 21 of another pipe body 20 ; the inner wall of the bell end 21 is integrally formed or processed with a sealing rubber ring installation structure 23 for accommodating the sealing rubber ring 24 .

When using the pipe for long-distance natural gas pipeline of the present utility model, the adjacent pipe body 20 is connected to the socket end 21 through the socket end 22, and the sealing rubber ring 24 is installed in the sealing rubber ring installation structure 23, so that the plug-in Adjacent pipe bodies 20 connected by bearings can be sealed and connected. Specifically, adjacent pipe bodies 20 are inserted through the socket end 22 of one pipe body 20 into the sealing rubber ring in the socket end 21 of the other pipe body 20. The method in the method realizes the socket-type flexible sealing connection of the two (as shown in Figure 4), so that after the connection, the adjacent pipe bodies 20 can move relative to each other along the axial direction of the pipe body 20, that is, they can be connected in the pipeline system after being plugged. In the case of integrity and no leakage, it can absorb a certain amount of axial expansion and contraction; moreover, since the long-distance natural gas pipeline pipe of the utility model is a ductile iron pipe, it has isotropic mechanical properties and corrosion resistance compared with pipeline steel pipes Strong, high-pressure airtightness, good material quality consistency, etc., the service life and cost performance are better than pipeline steel pipes, not only the service life is several times that of steel pipes, but also will not cause rolling along the line during use Cracks in the direction of the steel pipe and the phenomenon of tearing large cracks in the steel pipe instantly, that is, there will be no stress corrosion cracking such as "hydrogen-induced cracking" (HIC) and sulfide stress corrosion cracking (SCC) without obvious symptoms, so as to avoid sudden catastrophic accidents happened. At the same time, since there is no need to use welding to connect adjacent pipe bodies 20, and there is no need to carry out post-processing procedures such as on-site pressure testing, anti-corrosion treatment of weld seams, quality inspection, and elimination of welding stress, the construction period is greatly shortened, and on-site installation The construction speed is 6-7 times faster than that of the steel pipe, and the cost of installation, operation and maintenance of the pipe body 20 is reduced by more than 20%, and no leakage will occur due to weld seam failure during use.

In a preferred embodiment, the dimensional accuracy of the socket end is not less than ±0.2mm. To reduce the relative swing amount when the adjacent pipe bodies 20 are socket connected, so as to ensure the smooth progress of the socket connection.

In a preferred embodiment, the sealing working surface of the socket end 21 (the surface on the inner wall of the socket end 21 that cooperates with the outer working surface of the sealing rubber ring 24) and the sealing working surface of the socket end 22 (the surface of the socket end 22 and the external working surface of the sealing rubber ring 24) The surface roughness Ra of the outer peripheral surface corresponding to the sealing working surface of the opposite socket end 21 during the socket connection, which is matched with the inner working surface of the sealing rubber ring 24 when the adjacent pipe body 20 is socket connected) is ≯ 3.2 μm. Specifically, the sealing working surface of the socket end 21 is at least one surface of the sealing rubber ring installation structure 23. When the sealing rubber ring mounting structure 23 is an annular groove, the sealing working surface of the socket end 21 is in the shape of an annular groove The sealing rubber ring is installed on the bottom surface of the groove of the structure 23 to ensure that the tightness test (holding pressure for more than 24 hours) under the high-pressure gas line of no more than 15MPa will not drop pressure, so as to ensure that the pipeline formed after the long-distance natural gas pipeline is plug-in connected The nominal pressure of the pump is PN=10MPa (delivery pressure is 12.0~8.0MPa), and there is no risk of leakage. The surface roughness can be changed by machining, such as grinding or polishing, and a layer of organic resin coating can be applied on the ground or polished sealing surface according to the needs, so as to further improve the flexible sealing connection of the pipe body The tightness of the part.

In a preferred embodiment, the inner wall of the pipe body 20 is coated with a drag-reducing coating or provided with a drag-reducing and anti-corrosion coating, so as to improve the corrosion resistance of the pipe body 20 while reducing the resistance of the fluid flow to improve the performance of the pipe. The flow rate of the pipe body 20 is reduced to reduce the pressure drop of the fluid transported by the pipe body 20, thereby reducing the number of pressurization stations set up when transporting natural gas and reducing operating costs. Preferably, when the inner wall of the pipe body 20 is coated with a drag-reducing coating or a drag-reducing anti-corrosion coating, the outer wall of the pipe body 20 is coated with an anti-corrosion coating, so as to improve the comprehensive anti-corrosion ability of the pipe body 20 . Preferably, the thickness of the drag-reducing coating or the drag-reducing and anti-corrosion coating is not less than 200 μm, preferably in the range of 200 μm to 230 μm; the outer wall of the pipe body 20 is coated with an anti-corrosion coating with a thickness of not less than 70 μm, preferably in the range of 70 μm to 100 μm. Exemplarily, the drag-reducing coating or the drag-reducing anti-corrosion coating can be made of epoxy resin, polyurethane or polyurea; the anti-corrosion coating can be made of epoxy resin or polyurethane.

In some embodiments, the grade selection of ductile iron pipes should be selected according to the geographical environment temperature conditions for installation and use of the pipes. E.g:

Pipelines laid in low-latitude tropical or subtropical regions can be made of solid solution strengthened ferritic ductile iron materials with grades QT450-18, QT500-14, and QT600-10.

For pipelines laid in temperate or cold regions of middle and high latitudes or areas near the plateau snow line, or for transporting low-temperature natural gas released by LNG decompression and compression, the material of ductile iron pipes shall be made of materials with grades QT400-18L or QT350-22L The physical properties of these grades of materials are shown in Table 1 and Table 2, so as to ensure that the average low-temperature impact toughness of ductile iron pipe samples is not less than 12 joules when used at -20°C or -60°C.

The physical properties of the above-mentioned different grades of ductile iron materials are shown in Table 1 and Table 2:

Table 1. Mechanical properties of ductile iron grades (according to GB/T 1348-2019)

Note: The performance of the test rod is the basis for the acceptance of the mechanical properties of the cast pipe product, and the data collected by other methods (chemical composition data of thermal analysis, ultrasonic, spectral and chemical analysis, and metallographic analysis results) are the reference basis for the judgment of the cast pipe performance. The molten iron in the split casting test rod is the same molten iron taken when pouring the cast pipe.

Table 2. Impact absorption energy of low-temperature impact-resistant ductile iron V-notch casting samples

In a preferred embodiment, as shown in FIG. 1 , a guide section 201 is integrally formed or processed at the opening of the inner hole of the socket end 21 of the pipe body 20, and the guide section 201 is used to insert the socket end 22 of other pipe bodies 20. Guiding is provided in the socket end 22 of the tube 20 . As one of the implementations of the guide section 201, as shown in Figure 1, the guide section 201 is integrally formed or processed on the chamfer or bevel at the opening end of the inner hole of the socket end 21, and the chamfer or bevel is close to the socket The inner diameter of the end portion of the end 21 is greater than the inner diameter near the socket end, so as to reduce the resistance of the socket end 22 to insert the sealing rubber ring 24, shorten the time for inserting the sealing rubber ring 24, thereby improving the speed of field installation and construction. As another implementation of the guide section 201 , the guide section 201 is integrally formed or processed at the rounded corner of the opening end of the inner hole of the socket end 21 .

In a preferred embodiment, continue to refer to FIG. 1, the socket end 21 of the pipe body 20 is integrally formed or processed so that the pipe formed after the socket connection with the pipe body 20 has a certain axial expansion and diameter. The tolerance groove 202 for deflection. Exemplarily, the accommodating groove 202 is realized as a sunken groove structure capable of accommodating the socket end 22 inserted into the socket end 22 where it is located. Preferably, the inner diameter of the accommodating groove 202 is larger than the outer diameter of the socket end 22 inserted therein, so that the pipe body 20 inserted into the accommodating groove 202 through the socket end 22 can radially oppose the accommodating groove 202 A certain deflection occurs, which is the radial deflection described in the present invention, and the deflection amount of the radial deflection can be represented by the angle between the central axes of the two pipe bodies 20 connected by sockets. Preferably, the accommodating groove 202 is processed so that the pipe obtained by the socket connection has a radial deflection not greater than 4°. More preferably, the inner diameter of the accommodating groove 202 gradually increases from the side near the end of the socket end 21 to the side near the socket end 22, that is, the groove bottom of the accommodating groove 202 (accommodating the groove) The surface of the groove 202 opposite to the outer peripheral surface of the socket end 22 inserted therein) is inclined relative to the axial direction of the pipe body 20, that is, the groove depth of the groove 202 is from the side away from the socket end 22 to its close to the socket end. 22 gradually increases; the side wall of the end of the accommodation groove 202 away from the socket end 21 can also be set to incline from the bottom of the groove to the top of the groove to the side away from the socket end 21 (accommodating the groove The groove top of the groove 202 is closer to the outer peripheral surface of the socket end 22 inserted therein than the groove bottom of the groove 202), specifically, the groove 202 has only one side wall, and the side wall faces the socket inserted therein. The end of end 21. In order to ensure that the connected pipe has a deflection angle that meets the requirements, reduce the machining allowance of the allowance groove to improve the production effect, and at the same time, avoid the wall thickness of the socket end at the allowance groove from being too thin, so as to The strength of the socket end 21 is ensured, so as to provide conditions for the pipeline to resist geological disasters and reduce the amount of elbows, and at the same time provide a passage for the high-pressure gas in the pipeline to pressurize the sealing rubber ring 24 .

In a preferred embodiment, as shown in FIG. 1, a load-bearing section 203 is integrally formed or processed on the socket end 21 of the pipe body 20, so that the load-bearing section 203 located below the socket end 22 of the socket connection is connected to the socket end. 22 to support, to avoid clamping the seal rubber ring 24 between the socket end 22 and the socket end 21, the part below the socket end is overpressured by the body's own weight and causes uneven sealing effect up and down. Exemplarily, the guide section 201 is processed so that the one-sided fit gap between the socket end 22 inserted into the corresponding socket end 21 and the smallest diameter of the guide section 201 is not greater than 2mm; the load-bearing section 203 is processed so that it can be inserted into the The matching gap between the socket end 22 of the corresponding socket end 21 and the load-bearing section 203 is not greater than the matching gap between the socket end 22 and the minimum diameter of the guide section 201 . Preferably, the one-sided matching gap between the minimum diameter of the guide segment 201 and the socket end 22 inserted into the corresponding socket end 21 is between 1mm and 2mm.

Preferably, regardless of whether the guide section 201, the load-bearing section 203, the seal rubber ring installation structure 23 and the accommodation groove 202 are simultaneously arranged in the socket end 21, the guide section 201, the load-bearing section 203, the seal rubber ring installation structure 23 and the accommodation groove The order in which the groove 202 is arranged in the socket end 21 is: from the side where the end of the socket end 21 is located to the side close to the socket end 22, the guide section 201, the load-bearing section 203, the sealing section are arranged in sequence. Apron mounting structure 23 and tolerance groove 202, to avoid load-bearing section 203 from affecting the guiding effect of guide section 201 and affecting the deflection angle of the pipeline obtained by socket connection; Let the groove 202 work together to ensure that the pipe obtained by the socket connection has a deflection angle that meets the requirements.

As a preferred embodiment of the sealing rubber ring installation structure 23, continue to refer to shown in Figure 1, the sealing rubber ring installation structure 23 is integrally formed or processed in a stepped annular groove on the inner wall of the socket end 21, and the stepped annular groove includes a depth The shallower first annular groove 231 and the deeper second annular groove 232, and the first annular groove 231 and the second annular groove 232 communicate with each other; wherein, the stepped annular groove is used to accommodate the stepped sealing rubber ring 24 Specifically, the first annular groove 231 is used to accommodate the working section 242 of the sealing rubber ring 24 , and the second annular groove 232 is used to accommodate the hook 2411 of the sealing rubber ring 24 . Generally, the sealing working surface of the stepped annular groove at least includes the groove bottom of the first annular groove 231 .

In a preferred embodiment, as shown in FIG. 2 , the pipe for long-distance natural gas pipeline further includes a sealing rubber ring 24 fitted in the stepped annular groove. Preferably, as shown in FIG. 3 , the sealing rubber ring 24 includes a fixed section 241 and a working section 242. In this embodiment, for the convenience of description, the sealing rubber ring 24 extends radially outward to form a protrusion (that is, The section of the hook 2411) is called the fixed section 241, that is, the protrusion of the sealing rubber ring 24 and the position on the same radial direction as the protrusion are the fixed section 241, and the parts of the sealing rubber ring 241 other than the fixed section 241 are called Work section 242. Preferably, at least part of the cross-section of the free end of the working section 242 is "V" (fishtail), that is, the free end of the working section 242 has a gap; One side of the mouth end 21, and the "V"-shaped opening is set toward the side where the socket end 22 is located. At this time, the outer peripheral surface of the working section 242 of the sealing rubber ring 24, that is, the outer working surface of the sealing rubber ring 24 is against the groove bottom of the first annular groove 231 (the direction of the first annular groove 231 toward the socket end 22 inserted thereinto). surface, that is, the sealing working surface of the sealing rubber ring mounting structure 23). When adjacent pipe bodies 20 are socket connected, the socket end 22 is inserted into the sealing rubber ring 24 placed in the sealing rubber ring installation structure 23 of the adjacent socket end 21, and the sealing working surface of the socket end 22 at the socket connection is Compressed on the inner working surface of the sealing rubber ring (the two sides of the "V" shape are respectively distributed on the outer working surface and the inner working surface of the sealing rubber ring 24), so that the outer working surface of the sealing rubber ring 24 is Compress on the sealing working surface of the socket end 21, so that the connection of the adjacent pipe bodies 20 is a sealed connection. Further, the inner diameter of the inner working surface of the sealing rubber ring 24 gradually decreases from the end of the fixed section to the end of the working section, that is, the inner diameter of the sealing rubber ring 24 installed in the socket end 21 is from the outside (the socket end 21 where the end of 21) gradually narrows inwards, so that while the difficulty of inserting the socket end 22 is not increased, as the depth of the socket end 22 inserted into the socket end 21 increases, the socket end 22 will seal against the sealant. The compression amount of the ring 24 gradually increases, and the sealing performance of the sealing rubber ring 24 gradually improves, thereby improving the sealing performance of the socket-type flexible sealing connection. As shown in Figure 4.

The axial length of the sealing working surface of the socket end 22 is at least three times the axial length of the sealing rubber ring installation structure 23 .

In some embodiments, when the long-distance natural gas pipeline of the present utility model is connected with pipes, flexible sealing is preferred. The maximum deflection angle of the pipe body obtained by the flexible sealing connection can reach 4°, and the installation time of the interface is shortened to less than half a minute, and, even in cold seasons and regions, the installation time will not be increased due to the hardening of the sealing rubber ring ; At the same time, due to the increase of the deflection angle, it can also enhance the overall ability of the long-distance natural gas pipeline to deal with ground subsidence and earthquake damage to the pipeline; moreover, the increase of the deflection angle can also reduce the number of elbow fittings used in the installation process .

In a preferred embodiment, the sealing rubber ring 24 is an oil-resistant sealing rubber ring. Exemplarily, the sealing rubber ring is made of nitrile rubber with good oil resistance and wear resistance.

Fig. 4 exemplarily shows a long-distance natural gas transportation system according to an embodiment of the present invention.

As shown in Figure 4, the long-distance natural gas transmission system includes at least two aforementioned long-distance natural gas pipeline pipes; wherein, the socket end 22 of one of the two adjacent pipe bodies 20 is inserted into the other The sealing rubber ring 24 in the sealing rubber ring installation structure 23 of the socket end 21 of the root canal body 20, and the outer surface (seal working surface) of the socket end 22 abuts against the socket placed on another tube body 20 The inner working surface of the sealing rubber ring 24 in the sealing rubber ring installation structure 23 in the end 21, so as to press the outer working surface of the sealing rubber ring 24 on the sealing working surface of the sealing rubber ring installation structure 23 where it is located , so as to realize the socket type flexible sealing connection of two adjacent pipe bodies 20 . Since the connection mode of adjacent pipe bodies 20 is a socket-type sealed connection, while increasing the construction speed, it is not necessary to carry out pressure testing, anti-corrosion treatment of weld seams, quality inspection, and elimination of welding stress after subsequent on-site installation of pipe bodies. The post-processing process reduces the cost of installation, operation and maintenance of the pipe body 20 by 20% to 30%. In addition, the long-distance natural gas transmission system obtained by the socket-type sealed connection can absorb certain axial expansion and radial deflection. Therefore, it can resist the destructive force of geological disasters such as earthquakes and land subsidence.

Preferably, as shown in FIG. 4 , there is a gap between the end of the socket end 22 inserted into the corresponding socket end 21 and the side wall of the corresponding accommodation groove 202 . When the pipe body 20 is provided with an accommodation groove 202, and the sealing rubber ring used in the connection has a "V"-shaped cross-section, the gas in the connected pipeline can pass through the gap, and the socket end 22 at the connection The gap between the groove bottom wall and the accommodation groove 202 exerts pressure on the surface of the "V"-shaped opening of the sealing rubber ring, by increasing the inner and outer sealing working surface of the sealing rubber ring 24 and the socket end 22 at the connection. The pressure on the sealing working surface and the sealing working surface of the socket end 21 improves the sealing effect of the sealing rubber ring 24 .

What have been described above are only some embodiments of the present utility model. For those skilled in the art, without departing from the inventive concept of the present utility model, some modifications and improvements can be made, and these all belong to the protection scope of the present utility model.

Claims (18)

1. The pipe for the long-distance natural gas pipeline is characterized by comprising

The pipe body is provided with a female end and a straight pipe section, the female end is positioned at one end of the pipe body, and the end part, far away from the female end, of the straight pipe section is a socket end matched with the female end; wherein,

a sealing rubber ring mounting structure for placing a sealing rubber ring is arranged on the inner wall of the female end;

the pipe body is a nodular cast iron pipe.

2. The pipe for a long distance natural gas pipeline according to claim 1, wherein the dimensional accuracy of the female end is not less than ± 0.2mm; and/or

The surface roughness Ra of the sealing working surface of the female end and the sealing working surface of the female end is not more than 3.2 mu m.

3. The pipe for a long distance natural gas pipeline according to claim 1, wherein an inner wall of the pipe body is provided with at least one of a drag-reducing coating and a drag-reducing corrosion-preventing coating; or the inner wall of the pipe body is provided with either one of a drag reduction coating and a drag reduction anticorrosion coating, and the outer wall of the pipe body is provided with an antirust coating.

4. The pipe for a long distance natural gas pipeline according to claim 3, wherein the thickness of the drag-reducing coating layer or the drag-reducing corrosion-resistant coating layer is not less than 200 μm; the thickness of the rust-proof coating is not less than 70 μm.

5. The pipe for a long distance natural gas pipeline according to claim 1, wherein the nodular cast iron pipe uses any one of two low temperature impact resistant ferrite matrix nodular cast iron materials with the material grades of QT400-18L and QT350-22L, or uses any one of three solid solution strengthened ferrite matrix nodular cast iron materials with the material grades of QT450-18, QT500-14 and QT 600-10.

6. The long distance natural gas pipeline pipe according to any one of claims 1 to 5, wherein the packing rubber ring mounting structure is a stepped annular groove; the stepped annular groove comprises a first annular groove and a second annular groove, the first annular groove is formed in the inner wall of the female end and used for accommodating the working section of the sealing rubber ring, the second annular groove is used for accommodating a hook of the sealing rubber ring, the depth of the second annular groove is larger than that of the first annular groove, and the first annular groove and the second annular groove are communicated with each other;

the sealing face of the female end comprises at least the groove bottom of the first annular groove.

7. The pipe for a long distance natural gas pipeline according to claim 6, wherein at least one of a guide section, a bearing section and a tolerance groove for allowing a pipeline formed based on the pipe for a long distance natural gas pipeline to have an axial expansion amount and a radial deflection amount is provided on an inner wall of the female end of the pipe body;

the guide section is arranged so that a one-sided fit clearance at a minimum diameter of the guide section and a spigot end inserted to the respective spigot end is not more than 2mm;

the bearing section is arranged so that the fit clearance of the spigot end inserted into the corresponding socket end with the bearing section is not greater than the fit clearance at the smallest diameter of the bearing section with the guide section.

8. The pipe for a long distance natural gas pipeline according to claim 7, wherein the inside diameter of the allowance groove is gradually increased from a side near the female end to a side near the female end; and/or the side wall of the end part of the accommodating groove far away from the female end inclines from the groove bottom to the groove top to the side far away from the female end.

9. The pipe for a long distance natural gas pipeline according to claim 6, further comprising a packing rubber ring fitted in the stepped annular groove.

10. The pipe for the long-distance natural gas pipeline according to claim 9, wherein the sealing rubber ring comprises a working section and a fixing section with a hook, and at least part of the cross section of the free end of the working section is V-shaped;

the second annular groove is positioned on one side of the first annular groove, which faces the female end, and the V-shaped opening is arranged on one side, which faces the female end.

11. The pipe for a long distance natural gas pipeline according to claim 9, wherein the inner diameter of the inner working surface of the packing rubber is gradually reduced from the free end of the fixed section to the free end of the working section.

12. The pipe for a long distance natural gas pipeline according to claim 10, wherein the inner diameter of the inner working surface of the packing rubber is gradually reduced from the free end of the fixed section to the free end of the working section.

13. The pipe for a long distance natural gas pipeline according to claim 9, wherein the seal rubber ring is an oil-resistant seal rubber ring.

14. The pipe for a long distance natural gas pipeline according to claim 10, wherein the seal rubber ring is an oil-resistant seal rubber ring.

15. The pipe for the long-distance natural gas pipeline according to claim 11, wherein the sealing rubber ring is an oil-resistant sealing rubber ring.

16. The pipe for a long distance natural gas pipeline according to claim 12, wherein the seal rubber ring is an oil-resistant seal rubber ring.

17. A long-distance natural gas transportation system comprising at least two long-distance natural gas pipeline pipes according to any one of claims 1 to 16; wherein,

the outer surface of the socket end of one of the two adjacent pipe bodies abuts against the inner side working surface of the sealing rubber ring in the sealing rubber ring mounting structure in the socket end of the other pipe body, so that the outer side working surface of the sealing rubber ring is tightly pressed on the sealing working surface of the sealing rubber ring mounting structure where the sealing rubber ring is located.

18. The long-haul natural gas delivery system of claim 17, wherein the end of the spigot end inserted into the corresponding female end has a gap with a sidewall of the corresponding tolerance groove.

Images