Tension and compression test kettle in high-temperature and high-pressure environment

Abstract

The invention relates to the technical field of deep well drilling tool mechanical property test equipment, in particular to a high-temperature and high-pressure environment tension and compression test kettle which comprises a horizontal kettle body, and the two ends of the horizontal kettle body are each provided with a gas leakage compensation device and a clamp rod. The gas leakage compensation device comprises a one-way valve, an end cover and a cover plate; the cover plate is connected to one end of the horizontal kettle body, the outer end surface of the cover plate is hermetically connected with the end cover, the end cover and the cover plate are hermetically sleeved on the clamp rod on the same side, a first sealing piece is embedded at the joint of the cover plate and the clamp rod, and the one-way valve is hermetically arranged on the cover plate; the horizontal kettle body and the clamp rods and the cover plates at the two ends of the horizontal kettle body enclose a test cavity, and the clamp rods, the end covers and the cover plates on the same side enclose a collection cavity; two ends of the one-way valve are respectively communicated with the collection cavity and the test cavity on the same side, and the connection direction of the one-way valve is from the collection cavity to the test cavity. Through collaborative design of leakage collection and dynamic compensation, stable pressure control is realized, personnel maintenance intensity is reduced, and test safety and reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of scientific drilling engineering experimental equipment technology, specifically to a high-temperature and high-pressure environment tensile and compressive testing vessel. Background Technology

[0002] In scientific drilling projects, drill pipes and other downhole tools are often subjected to extreme environments of high temperature and high pressure, placing extremely stringent requirements on the mechanical properties and durability of drill pipe materials. Therefore, it is of great significance to conduct mechanical property tests on drill pipe materials under high temperature and high pressure environments in the laboratory, simulating actual downhole working conditions.

[0003] Horizontal high-temperature and high-pressure reactors are widely used in tensile and compression tests of drill pipe materials due to their ease of horizontal specimen clamping and good load alignment. In this type of testing apparatus, specimens are typically fabricated into small-scale proportions according to drilling material standards and fixed inside the horizontal reactor body using clamping rods. The clamping rods must penetrate both end caps of the horizontal reactor body to connect to external loading devices and apply tensile, compressive, or alternating loads.

[0004] Due to the weight of the horizontally arranged clamp rod and its axial movement during the test, instantaneous pressure fluctuations occur at the seal between the clamp rod and the end cap (hereinafter referred to as the end cap seal). This leads to gas leakage at the end cap seal, resulting in a decrease in pressure within the reactor cavity, i.e., the test chamber, and affecting the accuracy of the drill rod's mechanical properties test. Ensuring the sealing performance of the end cap seal during the test is one of the key challenges in maintaining the high-pressure environment inside the horizontal reactor.

[0005] During the test, the clamp rod needs to move axially with the specimen. For long tensile specimens, the axial displacement during the test can reach tens of millimeters, which leads to reciprocating friction and wear at the sealing interface, causing the end cap seal to fail, resulting in gas leakage and pressure fluctuations in the test chamber. These pressure fluctuations will directly cause the test conditions to deviate from the preset values, affecting the accuracy of the drill pipe mechanical performance data and reducing the test precision.

[0006] Furthermore, deep well operations often encounter high-temperature (e.g., 300℃) and high-pressure (e.g., 175MPa) environments, which can easily cause aging, deformation, or failure of sealing materials. Currently, end cap seals mostly use single static seals such as O-rings and lip seals, relying on the clamping flange to provide initial preload. This type of end cap seal structure has significant shortcomings under long-term dynamic conditions of high temperature and high pressure. The end cap seal is prone to deformation or wear, making gas leakage more likely, and pressure compensation is difficult to achieve; that is, the gas compensated for entering the test chamber will immediately leak through the end cap seal. In addition, frequent stops of the test to repressurize the test chamber not only affect efficiency but may also introduce additional test interference.

[0007] Therefore, given the special requirements of the high-temperature and high-pressure testing environment in drilling, there is an urgent need to develop a high-temperature and high-pressure environment tensile and compressive testing vessel that can adapt to the dynamic displacement of the clamp rod, has gas compensation capability, and enhances sealing performance, so as to improve the reliability, safety, and experimental efficiency of drill pipe material testing. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a high-temperature and high-pressure environment tensile and compressive testing vessel, which solves the technical problem that gas leakage is more likely to occur at the sealing point of the end cover seal of the existing high-temperature and high-pressure environment tensile and compressive testing vessel.

[0010] (II) Technical Solution

[0011] To achieve the above objectives, the high-temperature and high-pressure environment tensile and compressive test vessel of the present invention includes a horizontal vessel body, wherein a gas leakage compensation device and a clamping rod are provided at each end of the horizontal vessel body;

[0012] The gas leakage compensation device includes a one-way valve, an end cap, and a cover plate; the cover plate is connected to one end of the horizontal vessel and the outer end face of the cover plate is sealed to the end cap; the end cap and the cover plate are both sealed and sleeved on the clamp rod on the same side; a first sealing element is embedded at the connection between the cover plate and the clamp rod; and the one-way valve is sealed and disposed on the cover plate.

[0013] The horizontal vessel body, the clamp rods at both ends, and the cover plate form a test cavity, and the clamp rods, end caps, and cover plates on the same side form a collection cavity;

[0014] The two ends of the one-way valve are respectively connected to the collection chamber and the test chamber on the same side, and the conduction direction of the one-way valve is from the collection chamber to the test chamber.

[0015] Optionally, the gas leakage compensation device further includes a sleeve that is sealed to the outer end face of the cover plate; the sleeve is sealed onto the clamp rod on the same side;

[0016] The sleeve, the clamping rod, and the cover plate on the same side form a first flow guiding cavity, and the sleeve is provided with a first flow guiding hole that connects the collection cavity and the first flow guiding cavity.

[0017] Optionally, the gas leakage compensation device further includes a gas pump and a cartoon connector that is sealed to the annular top plate of the end cap;

[0018] The air inlet of the cartoon connector is connected to the air pump, and the exhaust end is connected to the collection chamber.

[0019] The first guide hole and the exhaust end of the cartoon connector are both arranged along the axial direction parallel to the clamp rod, and the two are offset in the radial direction of the clamp rod.

[0020] Optionally, the air inlet of the one-way valve is located on the extension line of the axis of the cartoon connector.

[0021] Optionally, the plurality of said cartoon connectors are evenly arranged around the axis of the clamp rod;

[0022] Multiple one-way valves are evenly arranged around the axis of the clamp rod.

[0023] Optionally, the gas leakage compensation device further includes an annular housing coaxial with and sealed to the cover plate; the annular housing is built into the test chamber;

[0024] The annular shell and the cover plate form a second flow guiding cavity; a second flow guiding hole is provided on the side of the annular shell facing the clamp rod, close to the clamp rod; the second flow guiding cavity, the second flow guiding hole and the test chamber are connected in sequence;

[0025] The outlet of the one-way valve is built into the second flow guide cavity.

[0026] Optionally, the one-way valve is inclined and the outlet of the one-way valve is far away from the second guide hole.

[0027] Optionally, the gas leakage compensation device further includes a second seal;

[0028] The second seal is clamped between the cover plate and the horizontal vessel body, and the three are connected by bolts; the axial direction of the bolts is parallel to the axial direction of the clamp rod.

[0029] Optionally, the first seal includes a metal skeleton sealing ring and a flexible sealing ring embedded in the cover plate;

[0030] The flexible sealing ring is fitted onto the clamp rod; the metal skeleton sealing ring is fitted onto the flexible sealing ring.

[0031] Optionally, the one-way valve includes a valve body, a valve core, and a spring;

[0032] The valve body has an internal flow channel; the two ends of the flow channel are respectively configured as the air inlet and the air outlet of the one-way valve; one end of the spring is connected to the inner wall of the valve body, and the other end is connected to the valve core.

[0033] The spring can elastically press against the valve core to seal the air inlet of the one-way valve.

[0034] (III) Beneficial Effects

[0035] The beneficial effects of this invention are:

[0036] The high-temperature and high-pressure environment tensile and compressive testing vessel is symmetrically designed, with the specimen clamping position located at the center of the testing chamber. This symmetrical layout ensures that pressure fluctuations or leaks generated inside the testing chamber during the test are essentially consistent at the pair of gas leakage compensation devices, thereby effectively reducing pressure disturbances inside the testing chamber and improving test accuracy.

[0037] The first sealing element is the primary sealing structure of the high-temperature and high-pressure environment tensile and compressive testing vessel, used to prevent gas leakage from the test chamber. An independent chamber, the collection chamber, is constructed to the side of the test chamber. This collection chamber forms the second sealing structure of the high-temperature and high-pressure environment tensile and compressive testing vessel, collecting any gas leaked from the first sealing structure and preventing leakage to the outside environment, thus protecting the environment. Simultaneously, the preset pressure of the collection chamber is higher than the preset pressure of the test chamber, creating a pressure gradient between the collection chamber and the test chamber. A one-way valve establishes a one-way connection between the collection chamber and the test chamber. When pressure leakage occurs in the test chamber, causing the pressure in the collection chamber to rise to the preset value, the one-way valve opens, allowing gas from the collection chamber to flow into the test chamber, achieving pressure compensation after gas leakage from the test chamber. This improves the sealing adaptability of the high-temperature and high-pressure environment tensile and compressive testing vessel to dynamic displacement of the clamp rods during the test. This pressure compensation mechanism responds quickly, without requiring the test to be stopped for pressure replenishment, effectively ensuring test efficiency and avoiding or reducing additional test interference.

[0038] Through the synergistic design of "leakage collection-dynamic compensation-sealing enhancement", the leakage problem between the clamp rod and the end cap through hole of the existing high temperature and high pressure environment tensile and compressive test vessel is effectively solved, achieving stable pressure control, reducing the intensity of personnel maintenance, and improving the safety and reliability of the test. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the high-temperature and high-pressure environment tensile and compressive testing vessel of the present invention;

[0040] Figure 2 for Figure 1 Sectional view along the middle AA;

[0041] Figure 3 for Figure 2 A sectional view along the middle edge BB;

[0042] Figure 4 for Figure 2 Enlarged view of point C in the middle;

[0043] Figure 5 This is a schematic diagram of the one-way valve of the present invention;

[0044] Figure 6 This is a cross-sectional view of the one-way valve of the present invention.

[0045] Explanation of reference numerals in the attached figures

[0046] 1: Rack;

[0047] 2: Loading device;

[0048] 3: Horizontal reactor body; 31: Box body; 32: Sample; 33: Second seal; 34: Cover plate; 35: End cap;

[0049] 4: Gas leakage compensation device; 41: Gas pump; 42: Cartoon connector; 43: Collection chamber; 44: First guide chamber; 441: First guide hole; 45: One-way valve; 451: Inlet; 452: Outlet; 453: Valve core; 454: Spring; 46: Second guide chamber; 461: Second guide hole;

[0050] 5: Clamp rod;

[0051] 6: First sealing element; 61: Flexible sealing ring; 62: Metal skeleton sealing ring. Detailed Implementation

[0052] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0054] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; "connection" can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] See Figures 1 to 4 This invention provides a high-temperature and high-pressure environment tensile and compressive testing vessel, which includes a clamping rod 5 coaxially arranged, a horizontal vessel body 3, and a gas leakage compensation device; a pair of gas leakage compensation devices 4 and a pair of clamping rods 5 are symmetrically arranged at both ends of the horizontal vessel body 3; the gas leakage compensation device includes a one-way valve 45, and an end cap 35, a cover plate 34, and a first sealing element 6 coaxially and sealed with the clamping rods 5; the outer end face of the cover plate 34 is sealed with the end cap 35, and the inner end face is connected to the horizontal vessel body 3; both the end cap 35 and the cover plate 34 are sleeved on the clamping rods 5. The three components together form a collection cavity 43; the clamp rod 5, the horizontal vessel body 3, and a pair of cover plates 34 form a test cavity; a first sealing element 6 is embedded at the connection between the cover plate 34 and the clamp rod 5. The first sealing element 6 can be embedded in the cover plate 34 and sleeved on the clamp rod 5; or the first sealing element 6 can be embedded in the clamp rod 5 and abut against the cover plate 34 for sealing; a one-way valve 45 is sealed on the cover plate 34; the air inlet 451 of the one-way valve 45 is connected to the collection cavity 43, and the air outlet 452 is connected to the test cavity; the conduction direction of the one-way valve 45 is from the collection cavity 43 to the test cavity.

[0057] In this embodiment, the high-temperature and high-pressure environment tensile and compression test vessel also includes a frame 1 and a loading device 2. The horizontal vessel body 3 is fixedly mounted on the frame 1, which provides a rigid support structure to ensure stable force transmission and precise equipment operation during the test, while also ensuring operational safety. The loading device 2 drives the clamp rods 5 to perform tensile or compressive actions on the sample 32 (drill rod) by outputting controllable force or displacement. After the two ends of the sample 32 are clamped by a pair of clamp rods 5, they move synchronously in opposite directions to apply an axial load to the sample 32. The test chamber of the horizontal vessel body 3 constructs a sealed extreme environment space, providing stable and controllable high-temperature and high-pressure conditions for tensile and compression tests to simulate the mechanical properties of the drill rod under actual harsh working conditions. The first sealing element 6 forms an initial sealing structure under the compression of the clamp rods 5 and the cover plate 34. The gas leakage compensation device 4 collects the gas leaking into the test chamber and circulates it back into the test chamber to ensure the test temperature and pressure inside the test chamber and to strengthen the sealing. End cap 35 and cover plate 34 can be integrated to eliminate the connection gap between them, prevent gas leakage through the connection gap, improve the sealing performance of collection chamber 43, and thus ensure the pressure replenishment effect of collection chamber 43 to test chamber.

[0058] To address the core requirements of cost control, experimental safety assurance, and operational stability optimization in the media selection process, nitrogen is prioritized as the working medium. As an inert gas, nitrogen possesses stable chemical properties. Under the high-temperature and high-pressure conditions set in the experiment, it can effectively avoid oxidation reactions or other chemical interactions with the sample 32 and the high-temperature and high-pressure tensile-compression test vessel, reducing potential safety hazards in the experimental system from the outset, while ensuring the accuracy and repeatability of experimental data. Furthermore, nitrogen has a mature industrial preparation process and ample supply. Compared to other inert media such as argon, it significantly reduces the procurement and usage costs of the medium. Its characteristic of no significant phase change or performance fluctuation over a wide temperature and pressure range further ensures the reliability of the test vessel's long-term continuous operation, fully meeting the practical needs of high-temperature and high-pressure tensile-compression testing.

[0059] In this embodiment, the high-temperature and high-pressure environment tensile and compressive testing vessel is symmetrically arranged, with the clamping position of the sample 32 located at the center of the testing chamber. This symmetrical layout ensures that pressure fluctuations or leaks generated inside the testing chamber during the test are essentially consistent at the pair of gas leakage compensation devices, thereby effectively reducing pressure disturbances inside the testing chamber and improving test accuracy.

[0060] The contact surfaces of the first sealing element 6 and the cover plate 34 with the clamp rod 5 form the first sealing structure of the high-temperature and high-pressure environment tensile and compressive testing vessel, used to prevent gas leakage inside the test chamber. However, in actual testing, due to the weight of the clamp rod 5 and its axial movement, gas leakage can still occur at the first sealing element 6. Therefore, this invention constructs an independent chamber, namely a collection chamber 43, on the side of the test chamber. The collection chamber 43 forms the second sealing structure of the high-temperature and high-pressure environment tensile and compressive testing vessel. This second sealing structure can collect the gas leaked from the first sealing structure, preventing gas leakage to the outside and protecting the environment. Simultaneously, a one-way connection path is established between the collection chamber 43 and the test chamber through a one-way valve 45. When the pressure in the test chamber leaks and causes the pressure in the collection chamber 43 to rise to a preset value, the one-way valve 45 opens, allowing the gas in the collection chamber 43 to flow into the test chamber through the one-way valve 45, achieving pressure compensation after gas leakage in the test chamber and improving the sealing adaptability of the high-temperature and high-pressure environment tensile and compressive testing vessel to the dynamic displacement of the clamp rod 5 during the test. This pressure compensation mechanism responds quickly, without requiring the test to be stopped for pressure replenishment, effectively ensuring test efficiency and avoiding or reducing additional test interference.

[0061] In this embodiment, the gas leakage compensation device further includes a second sealing element 33; the second sealing element 33 is clamped between the cover plate 34 and the horizontal vessel body 3, and the three are connected by bolts; the axial direction of the bolts is parallel to the axial direction of the clamp rod 5; the preset pressure of the collection chamber 43 is slightly greater than the preset pressure of the test chamber. Specifically, the box body 31 of the horizontal vessel body 3 is a pressure-resistant container with flanges at both ends, and its material is selected from high-temperature and high-pressure resistant alloy steel to ensure structural stability under extreme working conditions. The cover plate 34 is bolted to the flange of the box body 31 to facilitate the disassembly and assembly of the horizontal vessel body 3 and the cover plate 34 for maintenance and replacement of internal components; the second sealing element 33 is an O-ring seal, which is pressed between the cover plate 34 and the flange of the box body 31. Since the preset pressure of the collection chamber 43 is greater than the preset pressure of the test chamber, the gas in the collection chamber 43 can exert an axial force on the cover plate 34, pressing the cover plate 34 tightly onto the box 31. This, in conjunction with the pre-tightening force of the bolt along the axial direction of the clamp rod 5, improves the sealing effect at the second seal 33.

[0062] Optionally, in a test environment with a high temperature of 300℃ and a high pressure of 175MPa in the test chamber, the temperature inside the collection chamber 43 is set to 300℃, the air pressure is set to 176~177MPa, and the pressure difference between the two ends of the one-way valve 45 is set to 0.5~1MPa. Compared with the implementation where the preset air pressure of the test chamber and the collection chamber 43 is the same, this creates a certain pressure difference between the test chamber and the collection chamber 43, forming a pressure gradient distribution. On the one hand, this enhances the axial compressive force on the second seal 33, improving the sealing effect of the second seal 33. On the other hand, the air pressure in the collection chamber 43 that is higher than that in the test chamber can apply prestress to the one-way valve 45, increasing the "sensitivity" of the one-way valve 45 to the pressure difference between its two ends, and reducing the influence of the spring 454 of the one-way valve 45 on the opening resistance of the valve core 453.

[0063] In summary, this invention effectively solves the leakage problem between the clamp rod and the 34 through holes of the cover plate in the existing high-temperature and high-pressure environment tensile and compressive test vessel through the synergistic design of "leakage collection-dynamic compensation-sealing enhancement", achieves stable pressure control, reduces personnel maintenance intensity, and improves test safety and reliability.

[0064] Furthermore, the gas leakage compensation device 4 also includes a sleeve coaxially and sealingly connected to the outer end face of the cover plate 34; the sleeve is sealed and fitted onto the clamp rod 5 on the same side; the sleeve, clamp rod 5, and cover plate 34 on the same side form a first guide cavity 44, and the sleeve is provided with a first guide hole 441 connecting the collection cavity 43 and the first guide cavity 44. Specifically, when gas leakage occurs at the first seal 6, the test chamber and the collection cavity 43 are instantaneously connected, and a large amount of gas from the test chamber enters the collection cavity 43, causing the gas pressure in the test chamber to deviate from the set value, thus reducing the test accuracy. Based on this, a sleeve is added to the outer end face of the cover plate 34 to buffer the gas leaking from the test chamber at the first seal 6. When the gas in the test chamber enters the first guide cavity 44 through the first seal 6, the volume of the first guide cavity 44 is smaller than that of the collection cavity 43, and the aperture of the first guide hole 441 is smaller. Therefore, the flow rate of the first guide hole 441 per unit time is smaller, which allows the first guide cavity 44 to "block" the gas from the test chamber from seeping into the collection cavity 43. Only a small portion of the gas can leak into the first guide cavity 44, while most of the gas is blocked by the first guide cavity 44 and flows back into the test chamber, effectively "locking" the gas inside the test chamber, reducing the amount of gas leakage at the first seal 6, and ensuring the accuracy of the test.

[0065] Secondly, the gas leakage compensation device 4 also includes a gas pump 41 and a cartoon connector 42 that is sealed to the annular top plate of the end cover 35. The inlet end of the cartoon connector 42 is connected to the gas pump 41, and the exhaust end is connected to the collection chamber 43. The first guide hole 441 and the exhaust end of the cartoon connector 42 are both arranged along the axial direction parallel to the clamp rod 5, and the two are offset in the radial direction of the clamp rod 5, that is, the difference between the axis and the axis of the clamp rod 5 is d. Specifically, when the pressure in the collection chamber 43 is lower than the preset value, the gas pump 41 is started to pressurize the cartoon connector 42, that is, the collection chamber 43, to ensure that the pressure inside the collection chamber 43 is always within the preset pressure range, so as to timely replenish the pressure of the test chamber and improve the pressure replenishment adaptability to tests with large pressure fluctuations. Optionally, the cartoon connector 42 is a high-pressure connector with a shut-off function, and has a sealing valve core inside. When the connection is disconnected, the passage is cut off to ensure the airtightness of the collection chamber 43.

[0066] The axes of the first guide hole 441 and the cartoon connector 42 are offset, with a radial difference of d. This causes the flow paths of the leaking airflow discharged through the first guide hole 441 and the high-pressure airflow discharged through the cartoon connector 42 to be staggered, effectively avoiding direct contact between the two airflows and causing gas turbulence. This ensures stable airflow at the air inlet 451, enabling the one-way valve 45 to stably deliver gas into the test chamber.

[0067] In addition, the air inlet 451 is located on the extension line of the axis of the cartoon connector 42. The gas discharged through the cartoon connector 42 forms a high-pressure jet. By placing the air inlet 451 on the path of the high-pressure jet, the diffusion time of the high-pressure jet pressure inside the collection chamber 43 can be shortened, enabling the one-way valve 45 to operate efficiently and replenish the pressure to the test chamber in a timely manner.

[0068] In this embodiment, four cartoon connectors 42 are evenly arranged around the axis of the clamp rod 5; four one-way valves 45 are evenly arranged around the axis of the clamp rod 5. The evenly arranged multiple cartoon connectors 42 and multiple one-way valves 45 improve the efficiency of pressure compensation and adaptability to larger pressure fluctuations within the test chamber. Furthermore, the multiple air outlets 452 evenly jet into the test chamber, effectively reducing pressure disturbances and ensuring that the overall pressure value of the test chamber remains stable within a preset fluctuation range. Similarly, multiple air inlets 451 are evenly arranged within the collection chamber 43, effectively reducing pressure disturbances to the collection chamber 43 caused by leaked airflow.

[0069] Furthermore, the gas leakage compensation device 4 also includes an annular housing coaxially and sealed with the cover plate 34; the annular housing is built into the test chamber; the annular housing and the cover plate 34 form a second flow guiding cavity 46; a second flow guiding hole 461 is provided on the side of the annular housing facing the clamp rod 5, close to the clamp rod 5; the second flow guiding cavity 46, the second flow guiding hole 461, and the test chamber are connected in sequence; the air outlet 452 is built into the second flow guiding cavity 46. Specifically, the end cap 35, the cover plate 34, the sleeve, and the annular housing can be integrated to eliminate connection gaps and improve the airtightness of the corresponding cavities. The second flow guiding cavity 46 is used to block the airflow discharged through the air outlet 452, preventing the airflow from directly hitting the central area of ​​the test chamber, that is, reducing the test interference to the sample 32 at the center position of the test chamber and improving the test accuracy. The second guide hole 461 is located near the clamp rod 5 and near the first seal 6, so that the gas flowing out through the second guide hole 461 flows directly to the first seal 6 where the pressure fluctuation is large. Only in a very small area near the cover plate 34, that is, in the open cavity formed by the cover plate 34, the clamp rod 5 and the inner ring of the annular shell, a real-time dynamic compensation micro-circulation of airflow is formed to avoid or reduce the interference of gas leakage at the first seal 6 on the test.

[0070] It should be noted that the sealing connections of the end cap 35, the cover plate 34, the one-way valve 45, the sleeve, the cartoon connector 42, and the annular shell are existing technologies and can be sealed using sealing rings, sealing strips, or sealant, as long as the sealing effect is ensured. This invention primarily focuses on improving the test chamber, aiming to enhance the stability of the pressure within the test chamber.

[0071] The number of first guide holes 441 and second guide holes 461 can be set to multiple, and the diameter and specific number of holes can be reasonably set based on the pressure requirements. Optionally, multiple first guide holes 441 are evenly arranged around the axis of the clamp rod 5, and multiple second guide holes 461 are arranged similarly, in order to reduce the pressure disturbance of the airflow on the corresponding cavity.

[0072] In this embodiment, the axial length of the test chamber is 1000 mm, the axial length of the first guide cavity 44 does not exceed 30 mm, and the axial length of the second guide cavity 46 does not exceed 50 mm. The limitation on the axial length of the second guide cavity 46 and the first guide cavity 44 is mainly to avoid excessively large cavity volumes that would lead to slow gas pressure adjustment, thereby ensuring the gas microcirculation speed at the seal.

[0073] Optionally, the check valve 45 is tilted, with the tilt angle being 30°~60° between the axis of the check valve 45 and the axis of the clamp rod 5; and the outlet 452 is far away from the second guide hole 461. By setting the outlet 452 at the end far away from the second guide hole 461, when pressure leakage occurs at the first seal 6, the chamber space of the second guide cavity 6 can effectively buffer pressure fluctuations, preventing the check valve 45 from opening wide due to instantaneous pressure difference, thus reducing the impact of pressure fluctuations on the outlet 452, thereby avoiding excessive pressure entering the test chamber through the check valve 45, and improving the reliability of the check valve 45 at the gas leakage point of the first seal 6.

[0074] Secondly, the first sealing element 6 includes a metal skeleton sealing ring 62 embedded in the cover plate 34 and a flexible sealing ring 61; the flexible sealing ring 61 is sleeved on the clamping rod 5; the metal skeleton sealing ring 62 is sleeved on the flexible sealing ring 61. Specifically, the metal skeleton sealing ring 65 provides rigid support, effectively limiting the flexible sealing ring 61 and improving the sealing stability of the flexible sealing ring 61. The flexible sealing ring 61 seals through contact and compression with the clamping rod 5. Both the flexible sealing ring 61 and the inner ring of the cover plate 34 abut against the clamping rod 5 for sealing, serving as the first sealing structure. The flexible sealing ring 61 can be made of high-temperature resistant fluororubber, improving its adaptability to high temperature and high pressure and its wear resistance, thereby ensuring its sealing performance.

[0075] like Figure 5 and Figure 6 As shown, the one-way valve 45 includes a valve body, a valve core 453, and a spring 454. A flow guide channel is provided inside the valve body. The two ends of the flow guide channel are respectively configured as an inlet 451 and an outlet 452. One end of the spring 454 is connected to the inner wall of the valve body, and the other end is connected to the valve core 453. The spring 454 can elastically press against the valve core 453 to seal the inlet 451. Specifically, the one-way valve 45 is a spring-loaded one-way valve, and the starting pressure of the valve core 453 is adjusted by adjusting the material and structure of the spring 454. The valve body is made of forged carbon steel, and the sealing surface is ground to ensure a tight seal. The flow guide channel is linearly arranged to improve the smoothness of airflow within the one-way valve 45. The advantage of the spring-loaded check valve is that it opens and closes the corresponding size of the inlet 451 based on the pressure at the inlet 451 and outlet 452, i.e., based on the pressure difference. The greater the pressure difference, the greater the compression of the spring 454, and the greater the flow rate of the check valve 45 per unit time. This allows the check valve 45 to adaptively adjust the flow rate based on the pressure difference between the test chamber and the collection chamber 43, ensuring the pressure stability inside the test chamber.

[0076] This embodiment focuses on the mechanical property testing of drill pipe material sample 32 in a simulated downhole extreme environment (300℃ high temperature, 175MPa high pressure). During the test, the system dynamically maintains pressure stability through a gas compensation mechanism. At various stages of the tensile test, if slight leakage occurs due to clamp rod movement or leakage increases under high load, the gas in the collection chamber 43 is replenished to the horizontal vessel 3 (test chamber) through the one-way valve 45 under the pressure difference, offsetting the leakage and maintaining a sealing effect. Especially during the high-load plastic deformation stage of the sample, the increased pressure difference triggers a rapid compensation mechanism, increasing the opening of the one-way valve 45 to provide a large flow of gas compensation, absorbing pressure fluctuations, and ensuring the accuracy of test data and system stability. After the test, the pressure in the horizontal vessel 3 and the collection chamber is synchronously and slowly reduced by the control system. During the depressurization process, the pressure inside the collection chamber 43 is maintained slightly higher than the pressure inside the horizontal vessel 3, keeping the one-way valve closed during depressurization to prevent reverse gas flow and ensure operational safety. Specifically:

[0077] Initial pressurization phase: Before the test begins, the horizontal vessel 3 is preheated while gas is introduced into the test chamber. A slow pressurization strategy is adopted to gradually increase the internal pressure of the test chamber to the set working pressure to avoid gas leakage due to excessive instantaneous pressure and to ensure the pressure accuracy of the test chamber. At the same time, high-pressure gas slightly higher than the internal pressure of the horizontal vessel 3 is introduced into the collection chamber 43 through the connector 42. This pressure gradient distribution design has multiple benefits: First, the higher pressure generates a significant additional clamping force on the outside of the cover plate 34, effectively enhancing the sealing reliability of the first seal 6 between the cover plate 34 and the flange of the housing 31; second, an initial pressure gradient is established between the collection chamber 43 and the horizontal vessel 3, providing the necessary driving force for subsequent automatic pressure compensation.

[0078] The gas leakage stage of the steady-state test: During the initial loading stage of the tensile test, the clamp rod 5 moves at a slow and stable speed. Despite the presence of the first seal 6, a very small amount of gas leakage may still occur due to the weight of the clamp rod 5 and the high-pressure environment. At this time, since the pressure in the collection chamber 43 is maintained slightly higher than that in the horizontal vessel 3, a stable pressure gradient is formed. The gas enters the one-way valve 45 through the inlet 451, pushing the valve core 453 to compress the spring 454 and produce a slight displacement. The valve opening is limited, keeping the one-way valve 45 in a moderately open state. The gas in the collection chamber 43 replenishes the horizontal vessel 3 with a small and continuous flow rate. This continuous low-flow compensation not only completely offsets the micro-leakage at the sealing interface, but more importantly, maintains the "pressure self-reinforcing sealing" effect, effectively overcoming the defect of the gradual decay of the sealing effect of traditional sealing components during long-term operation.

[0079] When the test reaches the high-load plastic deformation stage, the displacement of the clamp rod 5 increases significantly, and the wear of the first seal 6 intensifies accordingly, which may lead to an increase in leakage. When leakage causes a decrease in the internal pressure of the horizontal vessel 3, the pressure difference between the collection chamber 43 and the horizontal vessel 3 increases, and the system enters a gas compensation state. The leaked gas first enters the first guide chamber 44, and then enters the collection chamber 43 under the action of the first guide hole 441. Because the circumferential diameter of the first guide hole 441 is much smaller than the circumferential diameter of the cartoon connector 42 at the top of the collection chamber 43, the exhaust ends of the first guide hole 441 and the cartoon connector 42 are completely misaligned in the horizontal direction, with no direct alignment. This avoids direct contact between the first guide hole 441 and the high-pressure gas entering the collection chamber 43 through the cartoon connector 42, which could lead to gas turbulence. When the internal pressure of the collecting chamber 43 is greater than the internal pressure of the horizontal vessel 3, gas enters the one-way valve 45 through the inlet 451, pushing the valve core 453 to compress the spring 454, causing a large displacement and increasing the opening of the one-way valve 45. This results in a corresponding increase in the compensation flow rate to cope with the increased leakage. The gas flows out from the outlet 452 of the one-way valve and first enters the second guide chamber 46. Under the guidance of the second guide hole 461, it flows towards the contact leakage area between the clamp rod 5 and the inner wall of the cover plate 34. This ensures that gas pressure fluctuations only occur in a very small area near the seal, preventing gas from flowing into the central test area and affecting the test. This keeps the pressure in the central area where the sample 32 is located stable, ensuring the accuracy of the test.

[0080] During this stage, due to the increased displacement of the clamp rod 5, gas leakage is highly likely to persist in the contact area between the clamp rod 5 and the inner wall of the through hole of the cover plate 34. This device allows the leaking gas to first enter the collection chamber 43 through the first guide hole 441 of the first guide chamber 44. Under the action of the first guide hole 441, the leaking gas avoids direct contact with the high-pressure gas input into the collection chamber 43 through the connector 42, thus preventing gas turbulence. When the gas leakage causes a decrease in the internal pressure of the horizontal vessel 3, the internal pressure of the collection chamber 43 becomes greater than that of the horizontal vessel 3. The gas pushes the valve core 453 to compress the spring 454 and enters the second guide chamber 46 through the one-way valve 45. Under the action of the second guide hole 461, the gas flows to the contact leakage area between the clamp rod 5 and the inner wall of the cover plate 34, completing the gas circulation and compensation in the gas leakage area.

[0081] In extreme cases, such as an abnormality or sudden large leak in the first seal 6, causing a rapid drop in internal pressure of the horizontal vessel 3, the system automatically activates a rapid compensation mechanism when the pressure difference reaches a critical set value. The four circumferentially arranged check valves 45 reach their maximum opening under the pressure difference, rapidly increasing the compensation flow rate to a higher level. This prevents further pressure drop inside the horizontal vessel 3 within a short time and quickly restores it to the set range. Simultaneously, the input power of the gas pump 41 increases, and the pressure within the collection chamber 43 increases. This higher pressure helps improve the sealing performance of the first seal 6, generating a greater axial clamping force and creating a stronger sealing effect, thereby actively inhibiting the continued expansion of the gas leakage gap.

[0082] Specimen fracture impact stage: When specimen 32 reaches its strength limit and fractures, two important physical effects occur: first, the clamp rod 5 experiences a sudden, rapid displacement; second, the instantaneous release of energy causes significant pressure fluctuations. The gas leakage compensation device of this invention exhibits excellent response characteristics to these effects: firstly, the continuously maintained high-pressure gas within the collection chamber 43 can press the cover plate 34, enhancing the sealing reliability at the first sealing element 6; secondly, when the fracture impact causes a momentary drop in pressure inside the horizontal vessel 3, the pressure difference between the collection chamber 43 and the test chamber instantly widens, causing the one-way valve 45 to fully open within a very short time, providing a large flow of gas compensation, effectively absorbing pressure fluctuations, and maintaining system stability. The pressure sensing system accurately records this characteristic pressure change, providing important reference for experimental data analysis.

[0083] To clearly explain the working mechanism and necessity of the high-temperature and high-pressure environment tensile and compressive testing vessel, we will take the TC4 titanium alloy (Ti-6Al-4V) tensile specimen as an example to illustrate the axial displacement generated at the moment of fracture in the high-temperature tensile test and its influence on the gas sealing performance.

[0084] According to Appendix A.4 of the national standard GB / T228.2—2015 "Metallic materials, tensile testing—Part 2: High temperature test method", this method is applicable to rod-shaped specimens with a diameter greater than or equal to 4 mm. A TC4 titanium alloy cylindrical specimen with a diameter of 40 mm was selected, and its original gauge length L0 was specified in the standard as L0=5d0=200 mm. Based on existing literature and experimental data, the elongation after fracture of this material under high temperature and high pressure is known to be between 15% and 20%.

[0085] In the tensile test, when specimen 32 breaks, the residual elongation of its gauge length after fracture can be calculated by the following formula: 0.2 × 200 mm = 40 mm.

[0086] The elongation is only the residual deformation displacement after the specimen 32 breaks. In reality, the axial displacement generated by the specimen 32 at the moment of breakage also includes elastic deformation. Therefore, the maximum deformation during the experiment is greater than the calculated value. In addition, the fracture process of the specimen 32 is sudden and impactful. At the moment of fracture, the clamp rod 5 will further separate to both ends, generating a new and larger displacement. This displacement will be released rapidly in a very short time, causing a violent impact on the seal between the clamp rod 5 and the cover plate 34 of the test vessel.

[0087] When specimen 32 fractures, the accumulated elastic strain energy inside is suddenly released, causing the testing machine's clamping system to withstand a severe impact load. Simultaneously, due to the sudden disappearance of the tensile force, the clamping rod 5 will experience a significant axial rebound displacement within a very short time. This dynamic response not only leads to gas leakage within the horizontal vessel 3 but may also interfere with the testing machine's sensors and data acquisition system.

[0088] Based on this, the present invention, through the synergistic design of "leakage collection-dynamic compensation-sealing enhancement", can effectively cope with the pressure fluctuations and gas leakage generated at the seal when the sample 32 reaches its strength limit and breaks, thereby improving the safety and reliability of the test.

[0089] End of test phase: After the test is completed, the pressure inside the horizontal vessel 3 and the collection chamber 43 is slowly reduced by the control system. Throughout the depressurization process, since the pressure inside the collection chamber 43 is maintained at a level slightly higher than that inside the horizontal vessel 3, the one-way valve 45 remains closed, effectively preventing the gas inside the horizontal vessel 3 from flowing back into the collection chamber 43, ensuring the safety and controllability of the depressurization process.

[0090] The gas leakage compensation device can completely collect and effectively reuse leaked gas, ensuring that no gas leaks into the atmosphere. Throughout the entire test, including the moment the sample 32 breaks, the internal working pressure of the horizontal vessel 3 remains highly stable, with a fluctuation range superior to traditional devices. The improved pressure stability directly enhances the accuracy and reliability of material performance test data. Under the effect of "pressure self-reinforcing sealing," the service life of the sealing system is significantly extended. It eliminates the need to interrupt the test due to pressure drop, greatly improving test efficiency and reducing gas consumption.

[0091] In summary, the high-temperature and high-pressure environment tensile and compressive testing vessel of the present invention, by innovatively introducing a gas compensation mechanism and the principle of "pressure self-reinforcing sealing" within a very small sealed space area at both end cover plates 34, effectively solves the technical problem of dynamic sealing under ultra-high pressure and high temperature conditions, and effectively solves the sealing problem at the cover plate 34 of the high-temperature and high-pressure environment tensile and compressive testing vessel. This can significantly improve the stability and reliability of the high-temperature and high-pressure environment tensile and compressive testing vessel equipment, providing reliable technical support for high-precision performance testing of drilling pipe materials and other petroleum equipment materials, and is of great significance for improving the safety and reliability of drilling equipment.

[0092] It should be understood that the above description of specific embodiments of the present invention is only for illustrating the technical approach and features of the present invention, and is intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. However, the present invention is not limited to the specific embodiments described above. All changes or modifications made within the scope of the claims of the present invention should be covered within the protection scope of the present invention.

Claims

1. A high-temperature and high-pressure environment tensile and compressive testing vessel, comprising a horizontal vessel body (3), characterized in that, The horizontal vessel body (3) is provided with a gas leakage compensation device (4) and a clamp rod (5) at each end. The gas leakage compensation device includes a one-way valve (45), an end cap (35), and a cover plate (34); the cover plate (34) is connected to one end of the horizontal vessel body (3) and the outer end face of the cover plate (34) is sealed to the end cap (35); the end cap (35) and the cover plate (34) are both sealed and fitted onto the clamp rod (5) on the same side; a first sealing element (6) is embedded at the connection between the cover plate (34) and the clamp rod (5); the one-way valve (45) is sealed and installed on the cover plate (34); The horizontal vessel body (3) and the clamp rods (5) and the cover plate (34) at both ends form a test cavity, and the clamp rods (5), end caps (35) and the cover plate (34) on the same side form a collection cavity (43). The two ends of the one-way valve (45) are respectively connected to the collection chamber (43) and the test chamber on the same side, and the conduction direction of the one-way valve (45) is the collection chamber (43) leading to the test chamber.

2. The high-temperature and high-pressure environment tensile and compressive testing vessel according to claim 1, characterized in that, The gas leakage compensation device (4) further includes a sleeve that is sealed and connected to the outer end face of the cover plate (34); the sleeve is sealed and fitted onto the clamp rod (5) on the same side; The sleeve, the clamp rod (5), and the cover plate (34) on the same side form a first flow guiding cavity (44), and the sleeve is provided with a first flow guiding hole (441) that connects the collection cavity (43) and the first flow guiding cavity (44).

3. The high-temperature and high-pressure environment tensile and compressive testing vessel according to claim 2, characterized in that, The gas leakage compensation device (4) also includes a gas pump (41) and a cartoon connector (42) that is sealed to the annular top plate of the end cap (35). The air inlet of the cartoon connector (42) is connected to the air pump (41), and the exhaust end is connected to the collection chamber (43). The exhaust ends of the first guide hole (441) and the cartoon connector (42) are both arranged along the axial direction parallel to the clamp rod (5), and the two are offset in the radial direction of the clamp rod (5).

4. The high-temperature and high-pressure environment tensile and compressive testing vessel according to claim 3, characterized in that, The air inlet (451) of the one-way valve (45) is located on the extension line of the axis of the cartoon connector (42).

5. The high-temperature and high-pressure environment tensile and compressive testing vessel according to claim 4, characterized in that, Multiple of the cartoon connectors (42) are evenly arranged around the axis of the clamp rod (5); Multiple one-way valves (45) are evenly arranged around the axis of the clamp rod (5).

6. The high-temperature and high-pressure environmental tensile and compressive testing vessel according to any one of claims 1-5, characterized in that, The gas leakage compensation device (4) further includes an annular housing that is coaxial with and sealed to the cover plate (34); the annular housing is built into the test chamber; The annular shell and the cover plate (34) form a second flow guiding cavity (46); a second flow guiding hole (461) is provided on the side of the annular shell facing the clamp rod (5) and located near the clamp rod (5); the second flow guiding cavity (46), the second flow guiding hole (461) and the test chamber are connected in sequence; The outlet (452) of the one-way valve (45) is built into the second flow guide cavity (46).

7. The high-temperature and high-pressure environment tensile and compressive testing vessel according to claim 6, characterized in that, The one-way valve (45) is inclined, and the outlet (452) of the one-way valve (45) is far away from the second guide hole (461).

8. The high-temperature and high-pressure environment tensile and compressive testing vessel according to any one of claims 1-5, characterized in that, The gas leakage compensation device also includes a second seal (33). The second seal (33) is clamped between the cover plate (34) and the horizontal vessel body (3), and the three are connected by bolts; the axial direction of the bolt is parallel to the axial direction of the clamp rod (5).

9. The high-temperature and high-pressure environment tensile and compressive testing vessel according to any one of claims 1-5, characterized in that, The first seal (6) includes a metal skeleton sealing ring (62) embedded in the cover plate (34) and a flexible sealing ring (61). The flexible sealing ring (61) is sleeved on the clamp rod (5); the metal skeleton sealing ring (62) is sleeved on the flexible sealing ring (61).

10. The high-temperature and high-pressure environmental tensile and compressive testing vessel according to any one of claims 1-5, characterized in that, The one-way valve (45) includes a valve body, a valve core (453), and a spring (454). The valve body has a flow channel inside; the two ends of the flow channel are respectively constructed as the air inlet (451) and the air outlet (452) of the one-way valve (45); one end of the spring (454) is connected to the inner wall of the valve body, and the other end is connected to the valve core (453). The spring (454) can elastically press against the valve core (453) to seal the air inlet (451) of the one-way valve (45).

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