Self-constant-pressure under-pressure testing tool

Abstract

The invention relates to a self-constant-pressure type under-pressure test tool, relates to the technical field of technical cutting equipment, and is used for solving the problem that a test tool cannot test a hot melting cutting tool in a constant-pressure state. Comprising a main pipe; the pressurizing assembly is arranged at one end of the main pipe and used for pressurizing an inner cavity of the main pipe; the overflow assembly is arranged at the other end of the main pipe and used for controlling the pressure in the inner cavity to be constantly kept at a preset pressure value; wherein a sealing test cavity is defined among the main pipe, the pressurizing assembly and the overflow assembly, and the hot melting cutting tool is fixed in the sealing test cavity for constant pressure test. The overflow assembly is arranged, so that when the hot melting cutting tool works and extra pressure is generated, the overflow assembly can work in time to relieve pressure, and the pressure in the sealing test cavity is always kept in a constant pressure state. Therefore, the constant-pressure test requirement of the hot-melting cutting tool is met.

Description

Technical Field

[0001] The invention relates to the technical field of cutting equipment, in particular to a self-constant pressure type pressure testing tool. Background Art

[0002] Hot melt cutting tools are special equipment used to cut pipes such as oil pipes, casings and drill pipes. This technology can complete the cutting operation by heating and igniting high-energy agents to form a ring-shaped, high-temperature, molten metal ion heat flow without using explosives and dangerous chemicals. Hot melt cutting tools need to be tested under constant pressure before use, but hot melt cutting tools will generate pressure when working. The test tooling in related technologies will be affected by this pressure, and hot melt cutting tools cannot be tested under constant pressure. Summary of the invention

[0003] The present invention provides a self-constant pressure type pressure testing tool, which solves the problem that the testing tool cannot test the hot melt cutting tool under a constant pressure state.

[0004] The present invention provides a self-constant pressure type pressure testing tool, which is used to test a hot melt cutting tool, comprising: a main pipe; and a pressurizing component, which is arranged on one end of the main pipe and is used to pressurize the inner cavity of the main pipe; and an overflow component, which is arranged on the other end of the main pipe and is used to control the pressure in the inner cavity to be constant at a preset pressure value; wherein a sealed test cavity is defined between the main pipe, the pressurizing component and the overflow component, and the hot melt cutting tool is fixed in the sealed test cavity for constant pressure testing.

[0005] In one embodiment, the overflow assembly includes: an overflow valve mounting seat, which is arranged on the other end of the main pipe; and an overflow valve assembly, which is at least partially slidably arranged in the overflow valve mounting seat; wherein, an overflow channel is arranged on the overflow valve mounting seat, and the overflow channel is connected to the inner cavity of the main pipe. When the pressure in the inner cavity is less than or equal to a preset pressure value, the overflow valve assembly is in sealing contact with the inner cavity wall of the overflow channel to block the overflow channel. When the pressure in the inner cavity is greater than the preset pressure value, the overflow valve assembly is pushed open, and the overflow channel is opened to overflow.

[0006] In one embodiment, a first mounting hole, a second mounting hole and a connecting hole are provided in the overflow valve mounting seat, the first mounting hole is used to connect with the main pipe, the second mounting hole is used to install the overflow valve assembly, the connecting hole is used to connect the first mounting hole and the second mounting hole, the overflow valve assembly can slide in the second mounting hole to open or close the connecting hole, and an overflow hole connected to the second mounting hole is also provided on the outer periphery of the overflow valve mounting seat, and the connecting hole, the second mounting hole and the overflow hole constitute an overflow channel.

[0007] In one embodiment, the overflow valve assembly includes: a cone head shaft, which is slidably disposed in a second mounting hole; and an elastic member mounting seat, which is connected to the overflow valve mounting seat and defines an installation chamber with the overflow valve mounting seat and the cone head shaft; and a spring, which is installed in the installation chamber; wherein, when the pressure in the inner cavity is less than or equal to a preset pressure value, the spring presses the cone head shaft against the connecting hole to block the overflow channel, and when the pressure in the inner cavity is greater than the preset pressure value, the cone head shaft is pushed open, and the overflow channel opens to overflow.

[0008] In one embodiment, the communicating hole is a tapered hole, and one end of the cone head shaft in contact with the communicating hole is a tapered annular surface, and the tapered annular surface cooperates with the tapered hole to seal the communicating hole.

[0009] In one embodiment, an annular sealing groove is formed on the conical annular surface, and a sealing ring is disposed in the annular sealing groove. The sealing ring is used to seal the gap between the conical annular surface and the inner wall surface of the communicating hole.

[0010] In one embodiment, a first magnetic component is installed at the tail end of the first mounting hole, an inner cavity is provided in the cone head shaft, the inner cavity is connected to the annular sealing groove, a second magnetic component is slidably provided in the inner cavity, and both ends of the second magnetic component extend into the annular sealing groove. The first magnetic component can magnetically attract the second magnetic component to move the second magnetic component toward the direction close to the first magnetic component, and both ends thereof slide in the annular sealing groove to press against the sealing ring.

[0011] In one embodiment, a mounting frame is provided at the tail end, and the mounting frame is used to fix the first magnetic member.

[0012] In one embodiment, the pressurizing assembly includes: an oil filling nipple, one end of which is sealed and connected to one end of the main pipe; and a pressure plate assembly, which is sealed and connected to the other end of the oil filling nipple, and the pressure plate assembly is used to pressurize the inner cavity.

[0013] In one embodiment, the pressure plate assembly includes: a pressure plate, which is sealed and connected to the other end of the oil filling short section; and a pressurization joint, which is arranged on the pressure plate and is used to pressurize the inner cavity; and an exhaust joint, which is arranged on the pressure plate and is used to exhaust the gas in the inner cavity; and an end plug, which is arranged on the pressure plate and is used to seal the inner cavity.

[0014] In one embodiment, it also includes an oil pipe seat, which is fixedly connected to the inner cavity of the main pipe. The oil pipe seat is connected to the hot melt cutting tool to fix it in the inner cavity.

[0015] In one embodiment, a monitoring device is further included, which is disposed on the overflow assembly and is used to monitor the temperature and pressure in the overflow assembly.

[0016] Compared with the prior art, the advantage of the present invention is that, when the hot melt cutting tool generates additional pressure during operation, the overflow component can be used to release the pressure in time, and the pressure in the sealed test chamber is always kept at a constant pressure state. This avoids the problem that the test tool in the related art cannot test the hot melt cutting tool under a constant pressure state. This satisfies the constant pressure test requirements of the hot melt cutting tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0018] Figure 1 2 is a main cross-sectional view of a self-constant pressure type pressure testing tool in an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Schematic diagram of the connection relationship between the middle pressurized component and the main pipe;

[0020] Figure 3 yes Figure 1 Schematic diagram of the connection relationship between the overflow assembly and the main pipe;

[0021] Figure 4 yes Figure 1 Section view at AA in the middle.

[0022] Figure 5 yes Figure 1 Magnified view at A in the middle;

[0023] Figure 6 yes Figure 5 Magnified view at B.

[0024] Reference numerals:

[0025] 10. Main pipe; 20. Pressurizing assembly; 21. Oil filling nipple; 22. Pressure plate assembly; 221. Pressure plate; 222. Pressure joint; 223. Exhaust joint; 224. End plug; 30. Overflow assembly; 31. Overflow valve mounting seat; 312. Second mounting hole; 313. Connecting hole; 314. Overflow hole; 315. First mounting hole; 3151. Tail end; 32. Overflow valve assembly; 321. Cone shaft; 3211. Content Cavity; 3212, annular sealing groove; 322, elastic member mounting seat; 323, spring; 324, sealing ring; 3241, inclined plane; 325, second magnetic member; 3251, top pressure member; 326, first magnetic member; 327, mounting frame; 40, oil pipe seat; 50, monitoring device; 51, pressure sensor; 52, temperature sensor; 100, self-constant pressure type pressure test tool; 200, hot melt cutting tool; 300, oil pipe. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] like Figure 1 As shown, the present invention provides a self-constant pressure type pressure test fixture 100, which is used to test a hot melt cutting tool 200, and includes a main pipe 10, a pressurizing component 20 and an overflow component 30. The pressurizing component 20 is arranged at one end of the main pipe 10, and is used to pressurize the inner cavity of the main pipe 10. The overflow component 30 is arranged at the other end of the main pipe 10, and is used to control the pressure in the inner cavity to be constant at a preset pressure value. A sealed test cavity is defined between the main pipe 10, the pressurizing component 20 and the overflow component 30, and the hot melt cutting tool 200 is fixed in the sealed test cavity for constant pressure testing.

[0028] In the above configuration, the overflow assembly 30 is provided so that when the hot melt cutting tool 200 generates additional pressure during operation, the overflow assembly 30 can work in time to release the pressure, and the pressure in the sealed test chamber is always maintained at a constant pressure state. This avoids the problem that the test tool in the related art cannot test the hot melt cutting tool 200 under a constant pressure state. This satisfies the constant pressure test requirements of the hot melt cutting tool 200.

[0029] Specifically, Figure 1 and Figure 3 As shown, in one embodiment, the overflow assembly 30 includes an overflow valve mounting seat 31 and an overflow valve assembly 32. The overflow valve mounting seat 31 is arranged on the other end of the main pipe 10, and the overflow valve assembly 32 is partially slidably arranged in the overflow valve mounting seat 31. An overflow channel is arranged on the overflow valve mounting seat 31, and the overflow channel is connected with the inner cavity of the main pipe 10. When the pressure in the inner cavity is less than or equal to a preset pressure value, the overflow valve assembly 32 is in sealing contact with the inner cavity wall of the overflow channel to block the overflow channel. When the pressure in the inner cavity is greater than the preset pressure value, the overflow valve assembly 32 is pushed open, and the overflow channel is opened for overflow.

[0030] Specifically, Figure 3 and Figure 5 As shown, in one embodiment, a first mounting hole 315, a second mounting hole 312 and a connecting hole 313 are provided in the relief valve mounting seat 31, the first mounting hole 315 is used to connect with the main pipe 10, the second mounting hole 312 is used to install the relief valve assembly 32, the connecting hole 313 is used to connect the first mounting hole 315 and the second mounting hole 312, the relief valve assembly 32 can slide in the second mounting hole 312 to open or close the connecting hole 313, and an overflow hole 314 connected to the second mounting hole 312 is also provided on the outer periphery of the relief valve mounting seat 31, and the connecting hole 313, the second mounting hole 312 and the overflow hole 314 constitute an overflow channel.

[0031] Specifically, Figure 3 and Figure 5 As shown, in one embodiment, the overflow valve assembly 32 includes a cone head shaft 321, an elastic member mounting seat 322 and a spring 323. The cone head shaft 321 is slidably disposed in the second mounting hole 312, the elastic member mounting seat 322 is connected to the overflow valve mounting seat 31, and defines an installation chamber with the overflow valve mounting seat 31 and the cone head shaft 321. The spring 323 is installed in the installation chamber. When the pressure in the inner cavity is less than or equal to the preset pressure value, the spring 323 presses the cone head shaft 321 against the connecting hole 313 to block the overflow channel. When the pressure in the inner cavity is greater than the preset pressure value, the cone head shaft 321 is pushed open, and the overflow channel is opened for overflow.

[0032] Specifically, Figure 3 and Figure 5 As shown, in one embodiment, the communicating hole 313 is a tapered hole, and one end of the cone head shaft 321 that contacts the communicating hole 313 is a tapered annular surface, and the tapered annular surface cooperates with the tapered hole to seal the communicating hole 313 .

[0033] Specifically, Figure 3 and Figure 5 As shown, in one embodiment, an annular sealing groove 3212 is opened on the conical annular surface, and a sealing ring 324 is arranged in the annular sealing groove 3212 . The sealing ring 324 is used to seal the gap between the conical annular surface and the inner wall surface of the communicating hole 313 .

[0034] Specifically, Figure 3 , Figure 5 and Figure 6 As shown, in one embodiment, a first magnetic component 326 is installed at the tail end 3151 of the first mounting hole 315, an inner cavity 3211 is provided in the cone head shaft 321, the inner cavity 3211 is connected to the annular sealing groove 3212, a second magnetic component 325 is slidably provided in the inner cavity 3211, both ends of the second magnetic component 325 extend into the annular sealing groove 3212, the first magnetic component 326 can magnetically attract the second magnetic component 325 so that the second magnetic component 325 moves in a direction close to the first magnetic component 326, and both ends thereof slide in the annular sealing groove 3212 to press the sealing ring 324.

[0035] Specifically, Figure 3 and Figure 5 As shown, in one embodiment, the second magnetic member 325 and the first magnetic member 326 are permanent magnets, and the second magnetic member 325 and the first magnetic member 326 have opposite polarities.

[0036] Specifically, Figure 5 As shown, in one embodiment, a mounting bracket 327 is provided at the tail end, and the mounting bracket 327 is used to fix the first magnetic member 326.

[0037] Specifically, Figure 2As shown, in one embodiment, the pressurizing assembly 20 includes an oil injection nipple 21 and a pressure plate assembly 22. One end of the oil injection nipple 21 is sealed and connected to one end of the main pipe 10, and the pressure plate assembly 22 is sealed and connected to the other end of the oil injection nipple 21, and the pressure plate assembly 22 is used to pressurize the inner cavity.

[0038] Specifically, Figure 2 As shown, in one embodiment, the pressure plate assembly 22 includes a pressure plate 221, a pressure joint 222, an exhaust joint 223 and an end plug 224. The pressure plate 221 is sealed and connected to the other end of the oil filling nipple 21, the exhaust joint 223 is arranged on the pressure plate 221 to discharge the gas in the inner cavity, and the end plug 224 is arranged on the pressure plate 221 to seal the inner cavity.

[0039] Specifically, Figure 1 As shown, in one embodiment, the self-constant pressure type pressure test tool 100 also includes an oil pipe seat 40, which is fixedly connected to the inner cavity of the main pipe 10, and the oil pipe seat 40 is connected to the hot melt cutting tool 200 to fix it in the inner cavity. At the same time, the oil pipe seat 40 is used to install the oil pipe 300.

[0040] Specifically, Figure 4 As shown, in one embodiment, a monitoring device 50 is further included. The monitoring device 50 is disposed on the overflow assembly 30 and is used to monitor the temperature and pressure inside the overflow assembly 30 .

[0041] Combine the following Figures 1 to 6 , describing a complete embodiment of the present application:

[0042] The present invention provides a self-constant pressure type pressure test tool 100, including a main pipe 10, the main pipe is made of high-quality alloy steel, the yield strength is 1069MPa, and the maximum high pressure resistance is 180Mpa. One end of the main pipe 10 is a pressurized end for injecting a medium, and the pressurized medium can be water, oil or gas, etc. The other end of the main pipe is an overflow end for maintaining a constant pressure, and the overflow end is provided with a fixed value overflow structure (overflow component 30).

[0043] Specifically, the overflow end is provided with an overflow channel and a cone head shaft 321, one end of the cone head shaft 321 is conical, and the connecting hole 313 of the overflow channel is an inverted cone. The cone head end of the cone head shaft 321 is pressed against the output port of the overflow channel (the output port of the connecting hole 313) under the action of a spring 323 (a disc spring can be used) to achieve sealing.

[0044] Specifically, a sealing ring 324 and an annular groove for accommodating the sealing ring are provided on the cone head shaft 321 , and the sealing ring 324 and the conical surface of the cone head shaft 321 form two sealing structures to ensure reliable sealing.

[0045] Specifically, an inner cavity 3211 is provided in the cone head shaft 321, and the inner cavity 3211 is connected to the annular sealing groove 3212. A second magnetic member 325 is movably provided in the inner cavity 3211, and a pressing member 3251 is provided between the second magnetic member 325 and the sealing ring (the pressing member 3251 is provided at both ends of the second magnetic member 325 and is an integrated structure with the second magnetic member 325). A first magnetic member 326 is fixedly provided in the overflow channel, and the first magnetic member 326 is fixed by a cross-shaped mounting frame (mounting frame 327). .

[0046] Specifically, when the cone head shaft 321 is against the output port of the overflow channel, the first magnetic part 326 correspondingly attracts the second magnetic part 325, and the first magnetic part 326 moves in the inner cavity 3211 toward the side close to the first magnetic part 326, and the sealing ring 324 is pushed out of the annular sealing groove 3212 by the pressing part 3251, so that the sealing ring 324 is attached to and sealed with the inner wall of the connecting hole 313 of the overflow channel.

[0047] Specifically, a pressure inclined surface is provided on the side of the sealing ring 324 facing the first magnetic member 326. When a gap is generated between the conical surface of the cone head shaft 321 and the inner wall of the overflow channel, the pressure in the cavity acts on the sealing ring 324 through the pressure inclined surface, so that the sealing ring 324 can be retracted into the annular groove.

[0048] Specifically, the cross section of the annular sealing groove 3212 is rectangular, and the side wall of the annular sealing groove 3212 is arranged along the normal of the conical surface of the cone head on the cone head shaft 321. The cross section of the sealing ring 324 is composed of a rectangular portion at the bottom and a triangular portion at the top. The width of the rectangular portion of the sealing ring 324 is the same as the width of the annular sealing groove 3212. The sealing ring 324 is elastic. When the pressing piece 3251 pushes the sealing ring 324 outward, the sealing ring 324 expands outward along the side wall of the annular groove so that the sealing ring 324 fits the inner wall of the overflow channel. The inclined surface 3241 of the triangular portion of the sealing ring 324 is a pressure-bearing inclined surface.

[0049] Specifically, the inner cavity 3211 is in the shape of a vertical strip, and the upper and lower ends of the inner cavity 3211 are respectively connected to two symmetrical locations on the annular sealing groove 3212. The second magnetic member 325 is also in the shape of a vertical strip, and the thickness of the second magnetic member 325 is smaller than that of the inner cavity 3211, so that the second magnetic member 325 can move in the inner cavity toward or away from the first magnetic member 326.

[0050] Specifically, the top pressure piece 3251 includes two arc-shaped top pressure strips arranged at the upper and lower ends of the second magnetic piece 325 (an integrally formed structure with the second magnetic piece 325, and of course, a split structure can also be provided), and the arc-shaped top pressure strip is arranged at the bottom of the annular sealing groove 3212, and the width of the arc-shaped top pressure strip is smaller than the width of the annular sealing groove 3212, so that the arc-shaped top pressure strip can move in the annular sealing groove 3212.

[0051] Specifically, the overflow end of the main pipe 10 is provided with an overflow valve mounting seat 31, the spring 323 is a disc spring arranged in the overflow valve mounting seat 31, and the end of the overflow valve mounting seat 31 is provided with an elastic member mounting seat 322; a pressing ring that presses against the disc spring is provided on the cone head shaft 321. By adjusting the installation form and compression amount of the disc spring, a variety of constant pressure values ​​can be achieved in the main pipe 10.

[0052] Specifically, the relief valve mounting seat 31 is provided with a temperature sensor 52 and a pressure sensor 51 for detecting the temperature and pressure inside the main pipe, so as to obtain the temperature and pressure information inside the main pipe 10 and facilitate the adjustment and control of the pressure inside the main pipe 10 .

[0053] Specifically, the overflow channel is arranged in the overflow valve mounting seat 31 , and an overflow hole 314 is arranged between the overflow channel and the top pressure ring on the overflow valve mounting seat 31 , and the overflowed medium flows out of the main pipe 10 from the overflow port.

[0054] Specifically, the pressurizing end is provided with an oil filling nipple 21, on which a pressure plate 221 is provided, and on which an end plug 224, a pressure joint 222 and an exhaust joint 223 are provided. The pressure plate 221 and the end plug 224 seal the pressurizing end, and the pressure pump injects the medium through the pressure joint 222 to increase the pressure in the cavity. When the medium is liquid, the exhaust joint 223 is used to exhaust the gas in the cavity.

[0055] Specifically, an oil pipe seat 40 for installing the oil pipe is provided in the main pipe 10 , and a hot melt cutting tool 200 is provided in the oil pipe, so that the hot melt cutting tool 200 can be used to test cutting the oil pipe in the main pipe 10 .

[0056] It should be noted that one end of the main pipe of the test fixture of the present invention is the pressurized end, and the pressure in the cavity is increased by injecting the medium. The pressurized end is sealed with a pressure plate, and the other end of the main pipe 10 is the overflow end, which adopts a fixed value overflow structure. There are two seals, a cone surface and a sealing ring 324, between the overflow valve mounting seat 31 and the cone head shaft 321 to ensure reliable sealing. A disc spring is installed between the cone head shaft 321 and the elastic member mounting seat 322. By adjusting the installation form and compression amount of the disc spring, a variety of constant pressure settings in the main pipe 10 can be achieved. When the thrust generated by the pressure in the main pipe 10 is higher than the thrust generated by the compression of the disc spring, it overflows. When the two are equal, the cone surfaces are instantly fitted to achieve constant pressure maintenance, which is suitable for occasions where additional pressure is generated when the tool is working and constant pressure testing is required.

[0057] From the specific description of the above specific implementation method, it can be seen that a second magnetic part is arranged in the cone head shaft, and a first magnetic part is arranged in the overflow channel. When the conical surface of the cone head shaft fits with the inner wall of the overflow channel, the first magnetic part attracts the second magnetic part through magnetic force, and the second magnetic part moves toward the side close to the first magnetic part in the inner cavity, and pushes the sealing ring out of the annular sealing groove through the pressing part, so that the sealing ring fits and seals with the inner wall of the overflow channel to assist the cone head shaft in sealing, and the sealing effect is better; and when a gap is generated between the conical surface of the cone head shaft and the inner wall of the overflow channel, the pressure in the cavity acts on the sealing ring through the pressure inclined surface, and the sealing ring drives the second magnetic part to move toward the side away from the first magnetic part. At this time, the bottom space of the annular sealing groove becomes larger, so that the sealing ring can be retracted into the annular sealing groove, thereby avoiding damage to the sealing ring due to the pressure in the cavity, and the service life of the sealing ring can be improved.

[0058] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0060] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A self-constant pressure type pressure testing tool (100), characterized in that: The self-constant pressure type pressure testing tool (100) is used to test a hot melt cutting tool (200), comprising: Supervisor (10); and a pressurizing assembly (20), disposed on one end of the main pipe (10), and used for pressurizing the inner cavity of the main pipe (10); and An overflow assembly (30) is arranged on the other end of the main pipe (10) and is used to control the pressure in the inner cavity to be constantly maintained at a preset pressure value; A sealed test cavity is defined between the main pipe (10), the pressurizing component (20) and the overflow component (30), and the hot melt cutting tool (200) is fixed in the sealed test cavity for constant pressure testing.

2. The self-constant pressure type pressure testing tool (100) according to claim 1, characterized in that: The overflow assembly (30) comprises: A relief valve mounting seat (31) is arranged on the other end of the main pipe (10); and A relief valve assembly (32) is at least partially slidably disposed in the relief valve mounting seat (31); Wherein, an overflow channel is provided on the overflow valve mounting seat (31), and the overflow channel is connected to the inner cavity of the main pipe (10). When the pressure in the inner cavity is less than or equal to the preset pressure value, the overflow valve assembly (32) is in sealing contact with the inner cavity wall of the overflow channel to block the overflow channel. When the pressure in the inner cavity is greater than the preset pressure value, the overflow valve assembly (32) is pushed open, and the overflow channel is opened to overflow.

3. The self-constant pressure type pressure testing tool (100) according to claim 2, characterized in that: The relief valve mounting seat (31) is provided with a first mounting hole (315), a second mounting hole (312) and a connecting hole (313); the first mounting hole (315) is used to connect with the main pipe (10); the second mounting hole (312) is used to mount the relief valve assembly (32); the connecting hole (313) is used to connect the first mounting hole (315) and the second mounting hole (312); the relief valve assembly (32) can slide in the second mounting hole (312) to open or close the connecting hole (313); an overflow hole (314) connected to the second mounting hole (312) is also provided on the outer periphery of the relief valve mounting seat (31); the connecting hole (313), the second mounting hole (312) and the overflow hole (314) constitute the overflow channel.

4. The self-constant pressure type pressure testing tool (100) according to claim 3, characterized in that: The relief valve assembly (32) comprises: a cone head shaft (321) slidably disposed in the second mounting hole (312); and an elastic member mounting seat (322) connected to the relief valve mounting seat (31) and defining a mounting chamber together with the relief valve mounting seat (31) and the cone head shaft (321); and A spring (323) is installed in the installation chamber; When the pressure in the inner cavity is less than or equal to the preset pressure value, the spring (323) presses the cone head shaft (321) against the connecting hole (313) to block the overflow channel; when the pressure in the inner cavity is greater than the preset pressure value, the cone head shaft (321) is pushed open and the overflow channel is opened to overflow.

5. The self-constant pressure type pressure testing tool (100) according to claim 4, characterized in that: The communicating hole (313) is a tapered hole, and one end of the cone head shaft (321) in contact with the communicating hole (313) is a tapered annular surface, and the tapered annular surface cooperates with the tapered hole to seal the communicating hole (313).

6. The self-constant pressure type pressure testing tool (100) according to claim 5, characterized in that: An annular sealing groove is provided on the conical annular surface, a sealing ring (324) is provided in the annular sealing groove, and the sealing ring (324) is used to seal the gap between the conical annular surface and the inner wall surface of the connecting hole (313).

7. The self-constant pressure type pressure testing tool (100) according to claim 6, characterized in that: A first magnetic component (326) is installed at the tail end (3151) of the first mounting hole (315), and an inner cavity (3211) is arranged in the cone head shaft (321), and the inner cavity (3211) is communicated with the annular sealing groove. A second magnetic component (325) is slidably arranged in the inner cavity (3211), and both ends of the second magnetic component (325) extend into the annular sealing groove. The first magnetic component (326) can magnetically attract the second magnetic component (325) so that the second magnetic component (325) moves in a direction close to the first magnetic component (326), and both ends of the second magnetic component (325) slide in the annular sealing groove to press the sealing ring (324).

8. The self-constant pressure type pressure testing tool (100) according to claim 7, characterized in that: The tail end is provided with a mounting frame (327), and the mounting frame (327) is used to fix the first magnetic member (326).

9. The self-constant pressure type pressure testing tool (100) according to claim 1, characterized in that: The pressurizing component (20) comprises: An oil injection nipple (21), one end of which is sealed and connected to one end of the main pipe (10); and A pressure plate assembly (22) is sealedly connected to the other end of the oil injection nipple (21), and the pressure plate assembly (22) is used to pressurize the inner cavity.

10. The self-constant pressure type pressure testing tool (100) according to claim 9, characterized in that: The pressure plate assembly (22) comprises: A pressure plate (221) is sealed and connected to the other end of the oil injection nipple (21); and a pressure joint (222), arranged on the pressure plate (221), for applying pressure to the inner cavity; and an exhaust joint (223), arranged on the pressure plate (221) and used for exhausting the gas in the inner cavity; and An end plug (224) is arranged on the pressure plate (221) and is used to seal the inner cavity.

11. The self-constant pressure type pressure testing tool (100) according to claim 1, characterized in that: It also includes an oil pipe seat (40), which is fixedly connected to the inner cavity of the main pipe (10). The oil pipe seat (40) is connected to the hot melt cutting tool (200) to fix it in the inner cavity.

12. The self-constant pressure type pressure testing fixture (100) according to claim 1 further comprises a monitoring device (50), wherein the monitoring device (50) is arranged on the overflow assembly (30) and is used to monitor the temperature and pressure inside the overflow assembly (30).

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