Pipeline flange type pressure test plug

Abstract

The utility model discloses a pipeline flange type pressure test plug, including screw, outer nut, blind hub, rear gasket, seal ring, front gasket and inner nut, blind hub, rear gasket, seal ring, front gasket and inner nut all sleeve on the screw in concentric mode, the center of screw is provided with through hole, seal ring is located between the front gasket and rear gasket, and the inner nut is located in the through hole. The blind hub is located outside the pipeline and fixed to a flange of the pipeline, the rear gasket, the sealing ring and the front gasket can be inserted into the pipeline, the blind hub, the rear gasket, the sealing ring and the front gasket are all located between the outer nut and the inner nut, and the sealing ring expands to seal the pipeline by screwing the outer nut. The novel pressure test plug is high in reusability, convenient to install in place, convenient to disassemble, short in operation time, high in safety coefficient and high in flexibility, and the damage of raw materials is zero.

Description

Technical Field

[0001] The present invention relates to a pressure test plug, in particular to a pipeline flange type pressure test plug. Background Art

[0002] Pipeline pressure test is a work to inspect the strength of pipeline welds and the tightness of intermediate flange connections in the pipeline after installation. The pressure test level is usually defined as four pressure levels: low-pressure pipeline 0.1≤P≤1.6MPa; medium-pressure pipeline 1.6<P≤10MPa; medium-high pressure pipeline 11<P≤49MPa; high-pressure pipeline 50≤P≤100MPa; ultra-high pressure P>101MPa.

[0003] Traditional inspection methods generally adopt the form of blind flange (FF, RF, API, ASE, HUB) + gasket (graphite gasket, RTJ-Ring, conforming gasket). The blind flange and the pipeline flange are sealed by gasket extrusion, and the flanges are connected by high-strength bolts. To ensure the tightness between the flanges, the flange bolts need to be tightened evenly with a torque wrench according to the flange management requirements (torque application) to achieve the sealing effect. This traditional method is applicable from low pressure to ultra-high pressure, but there are the following problems: The gasket uses extrusion hard sealing, which is easy to damage and has a low reuse rate; the test requires blind flanges of the same standard as the project, sealing gaskets and bolts of the same grade, and the direct test cost is high; the test steps are cumbersome (installing and removing flanges, applying torque), the auxiliary working hours of the crane are long, and the torque application time is long, etc. The process is cumbersome and the construction time is long; there are potential hazards of leakage and flange connector detachment. The flange sealing surface is easily damaged due to frequent use, the gasket has a low number of recycling times and a high leakage risk, the bolts are fatigued by cyclic use, and the NPT connectors are frequently disassembled, all of which will cause leakage or detachment during the test, posing safety hazards.

[0004] WO2017031233A1 discloses a pressure test plug, the structure of which is as Figure 5 shown. The pressure test plug has a plurality of circumferentially spaced metal tooth rows 138 and a set of circumferentially spaced holders 128, having a rear plate 136 and a front plate 122. The rear plate 136 and the front plate 122 can slide longitudinally along the shaft 112. Nuts 116, 118 are provided at both ends of the shaft, and there is a central hole 114 on the shaft 112. It may also include, for example, an O-ring 130, a hardened washer 132, a compression tube 134, etc. Figure 5 It shows a pressure test plug 110 inserted into the open end of a straight pipe section 164, and Figure 5The test plug 110 is shown tightened (i.e., in a compressed state) with the retainer 128 secured and advanced into secure clamping engagement with the inner surface of the straight pipe section 164. Of course, further tightening of the test plug 110 will cause the sealing element 124 of the test plug 110 to be compressed and expanded into sealing engagement with the inner wall. The sealing gasket 162 prevents any extrusion of the sealing element 124 into the gap between the cam element 126 and the shaft 112. The shaft 112 extends concentrically within the open passage 160 of the tapered element 126 and the cylindrical inner surface wall of the tube 164, and the metal teeth row 138 is securely engaged with the inner wall of the tube 164. The pressure test plug of WO2017031233A1 has the following problems: it adopts a technical solution of metal teeth engaging with the inner wall of the pipe to stop retreat. The pressure that the engaging part can withstand is relatively low, so this pressure test plug is only suitable for low-pressure or medium-pressure testing; on the other hand, the metal teeth will exert a large tension on the inner wall of the pipe during the engaging process, which will damage the inner wall of the pipe, especially for pipes with protective coating on the inner wall, this pressure test plug is not suitable; moreover, during repeated use, the metal teeth are easily squeezed and deformed, resulting in the pressure test plug being unable to effectively engage with the inner wall of the pipe and falling off. Utility Model Content

[0005] In view of the defects of the prior art, the present invention provides a pipeline flange type pressure test plug.

[0006] A pipeline flange type pressure test plug comprises a screw, an outer nut, a blind hub, a rear gasket, a sealing ring, a front gasket and an inner nut, wherein the blind hub, the rear gasket, the sealing ring and the front gasket are all concentrically sleeved on the screw, a through hole is provided at the center of the screw, the sealing ring is located between the front gasket and the rear gasket, the blind hub is outside the pipeline and is fixed to the flange of the pipeline, the rear gasket, the sealing ring and the front gasket can be inserted into the pipeline, the blind hub, the rear gasket, the sealing ring and the front gasket are all located between the outer nut and the inner nut, and the sealing ring is expanded and sealed by tightening the outer nut; the sealing ring is a rubber or polyester sealing ring.

[0007] Optionally, the through hole runs through one end of the screw to the other end, and the inside of the pipeline is communicated with the outside of the pipeline through the through hole; the two ends of the screw are provided with an upper threaded section and a lower threaded section, and a smooth shaft is provided between the upper threaded section and the lower threaded section; a clamping portion is formed at the top of the screw to prevent the screw from rotating with the rotation of the external nut; the blind hub is planar, and its maximum diameter is greater than or equal to the diameter of the pipeline flange; the blind hub has a protruding flange and a boss, the diameter of the flange is greater than the diameter of the boss, and the diameter of the flange is greater than or equal to the diameter of the pipeline flange; a retaining ring is also provided between the rear gasket and the sealing ring; a retaining ring is also provided between the sealing ring and the front gasket; the rear gasket and the front gasket are rigid gaskets; a bend is provided on the through hole.

[0008] This new type of pressure test plug has high reusability, is easy to install and remove, has a short operation time, a high safety factor, is convenient, has a "0" chance of leakage, has no risk of falling off, and greatly reduces costs. It has a wide range of applications, is not limited by pressure levels, has "0" damage to the formal flange sealing surface, "0" damage to the inner wall material of the pipeline, and "0" safety falling off risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a three-dimensional diagram of the pressure test plug;

[0010] Figure 2 This is the exploded view of the pressure test plug;

[0011] Figure 3 is a cross-sectional view of the pressure test plug;

[0012] Figure 4 It is the structural diagram of the test system;

[0013] Figure 5 It is a structural schematic diagram of a pilot plug in the prior art. DETAILED DESCRIPTION

[0014] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings, so that the above-mentioned and other purposes, features and advantages of the present invention will be clearer. The same reference numerals in all the drawings indicate the same parts. The drawings are not deliberately drawn to scale, and the focus is on illustrating the main purpose of the present invention.

[0015] The terms and words used in the following description and claims are not limited to the written meanings, but are only used by the novel person so that the novel can be clearly and consistently understood. Therefore, it is obvious to those skilled in the art that the following description of various embodiments of the novel is provided for the purpose of illustration only, and not for the purpose of limiting the novel as defined by the attached claims and their equivalents.

[0016] like Figure 1 As shown, the new pressure test plug is suitable for pressure testing of pipelines with flanges at the ends, and comprises a screw 1, an outer nut 2, a blind hub 3, a rear gasket 4, a sealing ring 7, a front gasket 6 and an inner nut 5. The blind hub 3, the rear gasket 4, the sealing ring 7 and the front gasket 6 are all concentrically sleeved on the screw 1, and threads are provided at both ends of the screw 1, so that the outer nut 2 and the inner nut 5 can be screwed on the screw 1. The sealing ring 7 is located between the front gasket 6 and the rear gasket 4, and the blind hub 3, the rear gasket 4, the sealing ring 7 and the front gasket 6 are all located between the outer nut 2 and the inner nut 5. The blind hub 3 is outside the pipeline, and the rear gasket 4, the sealing ring 7 and the front gasket 6 can be inserted into the pipeline. The blind hub 3, the rear gasket 4, the sealing ring 7 and the front gasket 6 can all slide freely along the screw 1.

[0017] See also Figure 2 and Figure 3 The center of the screw 1 is provided with a through hole 1.1, which runs from one end of the screw 1 to the other end. Through the through hole 1.1, the inside of the pipeline to be tested can be communicated with the outside of the pipeline. Both ends of the screw 1 are provided with threads, namely an upper thread section 1.3 and a lower thread section 1.5. A smooth shaft 1.4 is provided between the upper thread section 1.3 and the lower thread section 1.5. A clamping portion 1.2 is formed at the top of the screw 1 to prevent the screw 1 from rotating with the rotation of the external nut 2. The clamping portion 1.2 can be a hole shape, an external hexagonal shape, an external quadrilateral shape, etc., as long as it can prevent the screw 1 from rotating. For example, in the external hexagonal form, a wrench can be engaged with the clamping portion 1.2, so that when the external nut 2 rotates, the screw 1 does not rotate with the external nut 2.

[0018] The center of the blind hub 3 is provided with an opening 3.3, through which the screw 1 can pass. The blind hub 3 can be planar or boss-shaped, and the maximum diameter of the blind hub 3 is greater than or equal to the diameter of the pipe flange. Figure 2 As shown, the blind hub 3 has a protruding flange 3.2 and a boss 3.1, the diameter of the flange 3.2 is larger than the diameter of the boss 3.1, and the diameter of the flange 3.2 is larger than or equal to the diameter of the pipeline flange, so that the blind hub 3 is outside the pipeline, providing support for the pressure test plug. A retaining ring 8 can also be arranged between the rear gasket 4 and the sealing ring 7, and the retaining ring 8 can prevent the sealing ring from being squeezed into the rear gasket 4 when it is stressed. Of course, the retaining ring 8 can also be arranged between the sealing ring 7 and the front gasket 6, or between the sealing ring 7 and the front gasket 6, and between the rear gasket 4 and the sealing ring 7.

[0019] Figure 3The state diagram after the pressure test plug is inserted into the pipe 9 is shown. The end of the pipe 9 has a flange 9.1. The blind hub 3 can be fixed to the flange 9.1, for example, by a snap or a screw. The rear gasket 4, the sealing ring 7, the front gasket 6 and the inner nut 5 are located in the pipe 9, and the inner nut 5 is in a tightened state. After the blind hub 3 can be fixed to the flange 9.1, it can be engaged with the engaging portion 1.2 by a wrench, and then the outer nut 2 is rotated. As the outer nut 2 is rotated and tightened, the screw 1 will gradually extend out of the pipe 9. Since the blind hub 3 and the flange 9.1 are fixedly connected, the rear gasket 4 will abut the blind hub 3. The rear gasket 4 and the front gasket 6 are rigid gaskets and will not deform. The sealing ring 7 can be a rubber or polyester sealing ring, which can undergo elastic deformation. In this way, as the outer nut 2 is tightened, the rear gasket 4 and the front gasket 6 will apply pressure to the sealing ring 7. Under the action of pressure, the sealing ring 7 will expand and deform. As the sealing ring 7 expands, the sealing ring 7 will abut against the inner wall of the pipe 9, thereby achieving sealing of the pipe 9 through the sealing ring 7.

[0020] Next, combine Figure 4 Introduce the specific test process. Figure 4 The invention is introduced in the context of a water pressure test, but the novel pressure test plug can also be used for tests such as air pressure and oil pressure. Figure 4 It is shown that both ends of the pipeline 9 are sealed and pressure tested by pressure test plugs. Of course, the pressure test plug can be set at only one end of the pipeline 9 and the other end can be sealed by, for example, a blind flange. The through hole 1.1 is connected to the water pump 14 through the connector 1.6 and the valve 15. A downwardly bent elbow 13 can be set on the through hole 1.1 of the left pressure test plug. The elbow 13 is located in the pipeline 9. Figure 4 The pressure test plug on the left side is fixedly connected to the left flange of the pipeline 9 by a screw 11. An upwardly bent elbow 12 is installed on the pressure test plug on the right side of the pipeline 9, and the pressure test plug on the right side is fixedly connected to the right flange of the pipeline 9 by a buckle 10, and a pressure gauge 17 is connected to the through hole of the pressure test plug on the right side.

[0021] During the test, after the pressure test plug is fixed by a screw or a buckle, the outer nut 2 is tightened to expand the sealing ring 7 in the pressure test plug, and the pipeline 9 is sealed by the sealing ring 7. Then the water pump 14 is started to inject water into the pipeline 9. The current pressure value in the pipeline 9 can be read by the pressure gauge 17. When the set value is reached, the welding condition, sealing condition, pressure resistance value, etc. of the pipeline 9 can be tested.

[0022] This new type adopts a blind hub and a flange to be fixedly connected, and realizes pipeline sealing by inserting a sealing plug into the pipeline, which changes the practice of adding a blind plate and a gasket in the traditional pressure test process. It does not require torque and pressure test gaskets, saving the cost of pressure test gaskets and the labor cost of bolt torque. The construction steps are flexible and simple (installation and removal) and short in time. There is no leakage risk. The sealing ring adopts a soft sealing material and can be frequently reused (no leakage risk). The sealing ring does not damage the inner wall of the pipeline. It is not only suitable for pressure tests of conventional pipelines, but also more suitable for anti-corrosion coated pipelines with protective coatings on the inner wall. The blind hub and the formal pipeline flange are fixed with screws or buckles, so that the entire pressure test plug can withstand all the thrust generated by the continuous increase in pressure during the pressure test. It can withstand greater pressure and is more suitable for high pressure or ultra-high pressure testing.

[0023] This new type of pressure test plug has high reusability, is easy to install and remove, has a short operation time, a high safety factor, is convenient, has a "0" chance of leakage, has no risk of falling off, and greatly reduces costs. It has a wide range of applications, is not limited by pressure levels, has "0" damage to the formal flange sealing surface, and has "0" safety risks.

[0024] Although the technology has been illustrated and described with respect to one or more embodiments, changes and / or modifications may be made to the illustrated examples without departing from the spirit and scope of the appended claims. In particular, with respect to the various functions performed by the above-described components or structures (assemblies, devices, circuits, systems, etc.), the terms used to describe such components (including references to "means") are intended to correspond to any component or structure (e.g., functionally equivalent) that performs the specified function of the described component, even if not structurally equivalent to the disclosed structure that performs the function in the example embodiments described herein, unless otherwise specified. In addition, although a particular feature may have been disclosed with respect to one of several embodiments, such a feature may be combined with one or more other features in other embodiments as may be desired and advantageous for any given or particular application. In addition, to the extent that the terms "comprising," "including," "having," "having," "containing," or variations thereof are used in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term "comprising."

[0025] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited by the specific implementation disclosed above. At the same time, any person familiar with the technical field can make many possible changes and modifications to the present technical solution using the methods and technical contents disclosed above without departing from the scope of the present technical solution, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the present technical solution still falls within the scope of protection of the present technical solution.

Claims

1. A pipeline flange type pressure test plug, characterized in that: It includes a screw, an outer nut, a blind hub, a rear gasket, a sealing ring, a front gasket and an inner nut. The blind hub, the rear gasket, the sealing ring and the front gasket are all concentrically sleeved on the screw. A through hole is provided at the center of the screw. The sealing ring is located between the front gasket and the rear gasket. The blind hub is outside the pipeline and is fixed to the flange of the pipeline. The rear gasket, the sealing ring and the front gasket can be inserted into the pipeline. The blind hub, the rear gasket, the sealing ring and the front gasket are all located between the outer nut and the inner nut. The sealing ring expands and closes the pipeline by tightening the outer nut. The sealing ring is a rubber or polyester sealing ring.

2. The pipeline flange type pressure test plug according to claim 1, characterized in that: The through hole runs through one end of the screw rod to the other end, and the inside of the pipeline is communicated with the outside of the pipeline through the through hole.

3. The pipeline flange type pressure test plug according to claim 1, characterized in that: An upper thread segment and a lower thread segment are arranged at both ends of the screw rod, and a smooth shaft is arranged between the upper thread segment and the lower thread segment.

4. The pipeline flange type pressure test plug according to claim 1, characterized in that: A clamping portion is formed at the top end of the screw rod, which can prevent the screw rod from rotating along with the rotation of the outer nut.

5. The pipeline flange type pressure test plug according to claim 1, characterized in that: The blind hub is planar, and its maximum diameter is greater than or equal to the diameter of the pipeline flange.

6. The pipeline flange type pressure test plug according to claim 1, characterized in that: The blind hub has a protruding flange and a boss, the diameter of the flange is larger than the diameter of the boss, and the diameter of the flange is larger than or equal to the diameter of the pipe flange.

7. The pipeline flange type pressure test plug according to claim 1, characterized in that: A retaining ring is also arranged between the rear gasket and the sealing ring.

8. The pipeline flange type pressure test plug according to claim 1, characterized in that: A retaining ring is also arranged between the sealing ring and the front gasket.

9. The pipeline flange type pressure test plug according to claim 1, characterized in that: The rear gasket and the front gasket are rigid gaskets.

10. The pipeline flange type pressure test plug according to claim 1, characterized in that: A bent pipe is arranged on the through hole.

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