Tri-axial ultra-high pressure pressure-maintaining loading device

Abstract

The application provides a triaxial ultrahigh-pressure pressure-maintaining loading device, which realizes mechanical compensation of the gravity of a loading rod by improving the structure of the triaxial ultrahigh-pressure pressure-maintaining loading device. The triaxial ultrahigh-pressure pressure-maintaining loading device comprises an upper cover part, a loading rod and a main cylinder, the main cylinder is provided with spaced-apart main cavities and a containing cavity, the main cavities and the containing cavity are communicated through a first hole channel, the upper cover part is used to block the containing cavity, and the upper cover part is further provided with a second hole channel; the loading rod passes through the second hole channel, the containing cavity and the first hole channel to the main cavities in sequence; from top to bottom, the first hole channel is provided with, in sequence, a first sealing structure used to be matched with the loading rod, a first guide ring and a stop ring; the second hole channel is provided with, in sequence, a dustproof part used to be matched with the loading rod, a second guide ring and a second sealing structure; the first sealing structure comprises a plurality of sealing parts stacked in the axial direction; and / or the second sealing structure comprises a plurality of sealing parts stacked in the axial direction.

Description

Technical Field

[0001] This invention relates to the field of mechanical testing equipment technology, specifically to a triaxial ultra-high pressure holding and loading device. Background Technology

[0002] In triaxial ultra-high pressure holding and loading devices, pressurizing the workpiece typically relies on the downward movement of the loading rod, a process achieved by injecting pressure into the loading or balancing chamber to move the loading rod. However, in this pressurization mechanism, the weight of the loading rod and its attached components has a significant impact on testing accuracy. To counteract this gravity error, traditional methods adjust the air pressure in the upper and lower compensation chambers, theoretically generating an upward force that balances the weight of the loading rod. However, determining the precise compensation air pressure value in practical applications is extremely complex and sensitive. Too low a value cannot completely counteract gravity, while too high a value may introduce unnecessary additional forces, both leading to testing errors. Secondly, changes in internal system factors such as temperature and pressure distribution can cause fluctuations in the compensation pressure, affecting the stability of the loading rod and making the pressure state of the test piece unstable. Furthermore, this method, dependent on the accuracy of air pressure control and the system's resistance to external interference, limits further improvements in testing accuracy, especially under high-precision requirements. Finally, achieving precise compensation pressure control requires high-precision equipment, increasing system complexity, operational difficulty, and equipment cost. Summary of the Invention

[0003] The purpose of this invention is to provide a triaxial ultra-high pressure holding and loading device. By improving the structure of the triaxial ultra-high pressure holding and loading device, the gravity of the loading rod is offset by mechanical means. Thus, while ensuring effective and stable offsetting of the gravity of the loading rod, the structure of the triaxial ultra-high pressure holding and loading device is simplified and the cost is reduced.

[0004] To achieve the above objectives, the present invention provides a triaxial ultra-high pressure holding and loading device, comprising an upper cover, a loading rod, and a main cylinder. The main cylinder has a main cavity and a receiving cavity spaced apart from each other, and the main cavity and the receiving cavity are connected by a first channel. The upper cover is used to seal the receiving cavity, and the upper cover is also provided with a second channel. The loading rod passes sequentially through the second channel, the receiving cavity, and the first channel into the main cavity. From top to bottom, the first channel is sequentially provided with a first sealing structure, a first guide ring, and a retaining ring adapted to the loading rod. The second channel is sequentially provided with a dustproof component, a second guide ring, and a second sealing structure adapted to the loading rod. The first sealing structure includes a plurality of sealing components stacked axially. And / or, the second sealing structure includes a plurality of sealing components stacked axially.

[0005] By incorporating at least one sealing structure within the first and second channels, comprising several axially stacked seals, the weight of the loading rod is offset by mechanical support rather than pneumatic compensation, significantly improving system stability and testing accuracy. This reduces loading rod instability caused by changes in internal system factors and lowers reliance on high-precision equipment and complex control systems. Consequently, while ensuring effective and stable offsetting of the loading rod's weight, the structure of the triaxial ultra-high pressure holding loading device is simplified, and costs are reduced.

[0006] Optionally, a portion of the first channel is radially recessed to form a first mounting groove, and the first sealing structure is located within the first mounting groove; a portion of the second channel is radially recessed to form a second mounting groove, and the second sealing structure is located within the second mounting groove.

[0007] By setting up mounting grooves to accommodate the first and second sealing structures, on the one hand, space is provided for the first and second sealing structures, and on the other hand, axial positioning is limited, while ensuring that several sealing elements are located in the same mounting groove, thereby improving the support strength of the loading rod.

[0008] Optionally, the first channel is further provided with a third sealing structure, the third sealing structure including a single sealing element, the third sealing structure being located axially above the first sealing structure.

[0009] In this method, the third sealing structure is located above the first sealing structure, that is, closer to the cavity. As the first sealing part, it needs to withstand pressure from different directions. The setting of the third sealing structure helps to optimize the distribution of these pressures and reduce the situation where the deformation of the first sealing structure caused by uneven pressure weakens its axial support force on the loading rod.

[0010] Optionally, the first channel is further provided with a radially concave third mounting groove for mounting the third sealing structure; the radial dimension of the third mounting groove is smaller than the radial dimension of the first mounting groove. Thus, the first sealing structure has a larger contact area with the first channel, further optimizing its stability in supporting the loading rod along the axial direction.

[0011] Optionally, a fourth sealing structure is further provided between the first guide ring and the retaining ring. The fourth sealing structure includes a plurality of sealing elements stacked axially. The first guide ring ensures the coaxiality of the loading rod and the first channel, the retaining ring provides circumferential anti-rotation for the loading rod, and the fourth sealing structure is further provided between them. The fourth sealing structure also includes a plurality of sealing elements stacked axially.

[0012] By adding a fourth sealing structure between the first guide ring and the retaining ring, the sealing performance of the system is further enhanced, preventing leakage of the pressurized medium from the tiny gap between the loading rod and the channel. Furthermore, the overlapping seals along the axial direction provide additional axial support. This design helps to better distribute the gravitational load of the loading rod, improving the overall structural stability and load-bearing capacity.

[0013] Optionally, the first channel may also have a radially concave fourth mounting groove, the radial dimension of which is the same as that of the first mounting groove. This increases the installation strength between the fourth sealing structure and the fourth mounting groove.

[0014] Optionally, the radial and axial dimensions of the first, second, and fourth mounting slots are all identical. This increases the compatibility of the accessories, allowing them to be used interchangeably within these mounting slots.

[0015] Optionally, the portion of the loading rod located within the accommodating cavity is provided with a plug, the plug being sealed and adapted to the cavity wall of the accommodating cavity; the plug dividing the accommodating cavity into an upper cavity and a lower cavity; the main cylinder also has a first inlet channel and a first outlet channel communicating with the upper cavity, the first inlet channel and the first outlet channel extending radially; it also includes a second inlet channel and a second outlet channel communicating with the lower cavity, the second inlet channel and the second outlet channel extending radially.

[0016] The technical solution of this application utilizes a radially extending channel design to more effectively utilize the space within the accommodating cavity, avoiding excessive axial space occupation. The radially extending channel allows for smoother airflow into and out of the upper and lower cavities, reducing airflow resistance caused by channel bending or turning. Furthermore, the radially extending channel serves as additional structural support, enhancing the structural strength of the accommodating cavity or related components, thereby increasing the pressurization limit of the triaxial ultra-high pressure holding and loading device in this solution.

[0017] Optionally, the system also includes a third inlet channel and a third outlet channel communicating with the main cavity, the third inlet channel and the third outlet channel extending radially. This further increases the structural strength of the main cylinder.

[0018] Optionally, the first entry channel, the second entry channel, and the third entry channel are axially aligned; the first discharge channel, the second discharge channel, and the third discharge channel are axially aligned; and the first entry channel and the first discharge channel are at the same height, the second entry channel and the second discharge channel are at the same height; and the third entry channel and the third discharge channel are at the same height.

[0019] By employing axially aligned inlet and outlet channels, the airflow within the equipment becomes more orderly and controllable. This design helps reduce airflow turbulence, improves gas flow efficiency and stability, and, because the inlet and outlet channels are axially aligned and highly consistent, facilitates the uniformity and standardization of the sealing structure. This contributes to improved equipment sealing performance and prevents gas leakage.

[0020] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0022] Figure 1 This is a schematic diagram of the structure of the triaxial ultra-high pressure holding and loading device in an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Partial structural diagram;

[0024] Figure 3 This is a structural diagram of part of the cylinder block, showing the passageway;

[0025] Figure 4 This is a schematic diagram of the lock structure;

[0026] Figure 5 yes Figure 4 Top view;

[0027] Figure 6 This is one of the processes by which the lock structure changes from the locked position to the unlocked position in the embodiments of the present invention;

[0028] Figure 7 This is the second process in the embodiment of the invention where the lock structure changes from the locked position to the unlocked position;

[0029] Figure 8 This is the third process in the embodiment of the invention where the lock structure changes from the locked position to the unlocked position;

[0030] Figure 9 This is a schematic diagram of the unlocking tube;

[0031] Figure 10 yes Figure 9 Top view;

[0032] Figure 11 This is a bottom view of the transfer pipe;

[0033] Figure 12 This is a schematic diagram of the push rod structure;

[0034] Figure 13 This is a side view of the retaining ring;

[0035] Figure 14 This is a top view of the retaining ring;

[0036] Figure 15 This is a structural diagram of the upper cover.

[0037] Figure 16 This is a schematic diagram of the master cylinder;

[0038] Figure 17 yes Figure 16 A schematic diagram of its cross-section.

[0039] Figure label:

[0040] 100-Cylinder body; 101-Main cavity; 102-Channel; 102a-Insertion; 102b-Slot; 102b-1-Slot top wall; 102b-2-Slot bottom wall; 102b-3-Slot side wall; 103-Lower cover; 104-Upper cover; 104-1-Second channel; 104-1a-Fifth mounting slot; 104-1b-Sixth mounting slot; 104-1c-Second mounting slot; 105-Main cylinder; 101-Main cavity; 106-Receiving cavity; 106-1-Upper cavity; 106-2-Lower cavity; 107-First channel; 107-1-Third mounting slot; 107-2-First mounting slot; 107-3-Fourth mounting slot; 107-4-Eighth mounting slot; 107-5-Seventh mounting slot; 108a-First inlet channel; 108b-First outlet channel; 109a-Second inlet channel; 109b-Second outlet channel; 110a-Third inlet channel; 110b-Third outlet channel; 111-Sealing part; 112-Flange; 200-Push rod; 201-Front rod section; 202-Stop part; 202a-Retaining ring; 203-Rear rod section; 200-1-Transfer pipe; 200-2-Unlocking pipe; 300-Lock structure; 301-Petal part; 301a-Inner side; 301b-Outer side; 301-1-Head end; 301-2-Tail end; 302-Head spring; 303-Tail spring; 304-Mounting groove; 400-Loading rod; 401-Plug; 900-Test piece. Detailed Implementation

[0041] This invention provides a triaxial ultra-high pressure holding and loading device. By improving the structure of the triaxial ultra-high pressure holding and loading device, the gravity of the loading rod is offset by mechanical means. Thus, while ensuring effective and stable offsetting of the gravity of the loading rod, the structure of the triaxial ultra-high pressure holding and loading device is simplified and the cost is reduced.

[0042] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0044] Please refer to Figures 1 to 17 , Figure 1 This is a schematic diagram of the structure of the triaxial ultra-high pressure holding and loading device in an embodiment of the present invention; Figure 2 yes Figure 1 Partial structural diagram; Figure 3 This is a structural diagram of part of the cylinder block, showing the passageway; Figure 4 This is a schematic diagram of the lock structure; Figure 5 yes Figure 4 Top view; Figure 6 This is one of the processes by which the lock structure changes from the locked position to the unlocked position in the embodiments of the present invention; Figure 7 This is the second process in the embodiment of the invention where the lock structure changes from the locked position to the unlocked position; Figure 8 This is the third process in the embodiment of the invention where the lock structure changes from the locked position to the unlocked position; Figure 9 This is a schematic diagram of the unlocking tube; Figure 10 yes Figure 9 Top view; Figure 11 This is a bottom view of the transfer pipe; Figure 12 This is a schematic diagram of the push rod structure; Figure 13 This is a side view of the seal; Figure 14 This is a top view of the seal; Figure 15 This is a structural diagram of the upper cover. Figure 16 This is a schematic diagram of the master cylinder; Figure 17 yes Figure 16 A schematic diagram of its cross-section.

[0045] like Figure 1 as well as Figures 15 to 17 As shown, the triaxial ultra-high pressure holding and loading device includes a cylinder body 100 and a loading rod 400. The cylinder body 100 includes an upper cover 104, a lower cover 103, and a main cylinder 105. The main cylinder 105 has a spaced-apart main cavity 101 and a receiving cavity 106. The main cavity 101 serves as a test cavity to accommodate the test piece and to perform pressure testing on the test piece.

[0046] In the example shown, a receiving cavity 106 is provided on the upper side of the main cylinder 105, extending through the upper surface of the main cylinder 105. A main cavity 101 is provided on the lower side of the main cylinder 105, extending through the lower surface of the main cylinder 105. The main cylinder 105 has a variable diameter structure, with the portion containing the receiving cavity 106 radially recessed relative to the portion containing the main cavity 101. The receiving cavity 106 is used to accommodate the plug 401 of the capping rod. The portion of the loading rod 400 located within the receiving cavity 106 is fitted with the plug 401, which is sealed and adapted to the cavity wall of the receiving cavity 106. The plug 401 divides the receiving cavity 106 into an upper cavity 106-1 and a lower cavity 106-2. The upper cavity 106-1 is located further away from the main cavity 101, and the lower cavity 106-2 is located closer to the main cavity 101.

[0047] The main cavity 101 and the receiving cavity 106 are connected by a first channel 107. The first channel 107 extends axially, that is, it is distributed perpendicular to the receiving cavity 106 and the main cavity 101. The inner diameter of the first channel 107 is smaller than that of the receiving cavity 106 and the main cavity 101 so as to be compatible with the radial dimension of the loading rod 400.

[0048] The upper cover 104 is used to seal the receiving cavity 106. The upper cover 104 has a flange structure, with its lower part protruding to be inserted into the receiving cavity 106 through the opening of the receiving cavity 106. Its edge is pressed against the upper surface of the main cylinder 105 and is aligned with the upper surface of the main cylinder 105.

[0049] The upper cover 104 is also provided with a second channel 104-1. The second channel 104-1 extends axially through the upper cover 104 and is used to insert the loading rod 400. The second channel 104-1, the first channel 107, the receiving cavity 106, and the main cavity 101 are coaxially arranged. The loading rod 400 passes sequentially through the second channel 104-1, the receiving cavity 106, and the first channel 107 into the main cavity 101, and can move axially up and down. The length of its upward and downward movement path is limited by the retaining ring described below, and the specific limiting method will be explained in detail later.

[0050] From top to bottom, the first channel 107 is sequentially provided with a first sealing structure, a first guide ring, and a retaining ring for adaptation to the loading rod 400. The first guide ring is adapted to the loading rod 400 to ensure coaxiality with the first channel 107 during its movement. Specifically, the first channel 107 is radially concave to form an eighth mounting groove 107-4 for accommodating the first guide ring. The retaining ring is used to provide a circumferential anti-rotation fit to the loading rod 400. Axially, the retaining ring is located on the side closest to the main cavity 101. The inner wall of the first channel 107 is radially concave to form a seventh mounting groove 107-5, which is used to accommodate the retaining ring. One end of the seventh mounting groove 107-5 penetrates the wall of the main cavity 101 to communicate with it.

[0051] The anti-rotation engagement between the retaining ring and the loading rod 400 can be a spline engagement, where a spline is provided on the retaining ring or the loading rod 400, and a corresponding spline groove is provided on the other side. When the loading rod 400 is inserted into the first channel 107, the spline and spline groove engage, thereby preventing the loading rod 400 from rotating circumferentially. Alternatively, a keyway engagement can be used: one or more keys are provided on the loading rod 400, and keyways are provided at corresponding positions on the retaining ring or the first channel 107. The engagement of the keys and keyways restricts the circumferential rotation of the loading rod 400. Alternatively, an elastic locking element can be used: elements such as spring clips or elastic rings are used, which, after installation, can hold the loading rod 400 radially, thereby preventing its circumferential rotation. Of course, a shape fit can also be used: by designing a special shape fit, such as a polygonal cross-section or a non-circular cross-section, a tight circumferential fit is formed between the loading rod 400 and the retaining ring or the first channel 107. All of the above engagement methods are within the scope of protection of this patent. If a spline or keyway fit is used, the axial extension dimension of the slot limits the axial movement path of the loading rod 400. In other words, the two ends of the slot restrict the two extreme positions of the loading rod 400's axial movement.

[0052] The second channel 104-1 is sequentially provided with a dustproof component, a second guide ring, and a second sealing structure adapted to the loading rod 400. The dustproof component is used to prevent external dust and impurities from entering the receiving cavity 106. The first sealing structure includes a plurality of axially stacked sealing components; and / or, the second sealing structure includes a plurality of axially stacked sealing components.

[0053] Specifically, the first and second sealing structures may include at least two axially stacked seals, with the loading rod 400 passing through the middle of the seal. The seals may employ one or more of the following sealing structures: metal flat gasket seal, C-ring seal, Wood's seal, double cone ring seal, fingertip seal, and O-ring seal, to provide axial support for the loading rod 400. In this application, the first, second, and subsequent fourth sealing structures all refer to sealing devices composed of two or more independent complementary seals, and the structure and type of each seal can be selected by those skilled in the art.

[0054] By incorporating at least one sealing structure within the first channel 107 and the second channel 104-1, the sealing structure comprising several axially stacked seals allows the gravity of the loading rod 400 to be offset by mechanical support rather than pneumatic compensation, thereby significantly improving system stability and testing accuracy. This reduces instability of the loading rod 400 caused by changes in internal system factors, while also reducing reliance on high-precision equipment and complex control systems. Thus, while ensuring effective and stable offsetting of the gravity of the loading rod 400, the structure of the triaxial ultra-high pressure holding loading device is simplified, and costs are reduced.

[0055] In the above embodiment, a portion of the first channel 107 is radially recessed to form a first mounting groove 107-2, and a first sealing structure is located within the first mounting groove 107-2. A portion of the second channel 104-1 is radially recessed to form a second mounting groove 104-1c, and a second sealing structure is located within the second mounting groove 104-1c.

[0056] The term "outer" is defined relative to the axial centerline of the master cylinder 105, which extends along the axis and passes through the center of the cylinder body. The direction radially towards the axial centerline is "inner," and vice versa. This provides space for the first and second sealing structures, limiting their axial movement while ensuring that multiple seals are located in the same mounting groove, thus improving the support strength for the loading rod 400.

[0057] Optionally, the first channel 107 is further provided with a third sealing structure, which includes a single sealing element and is located axially above the first sealing structure. The first channel 107 is also provided with a radially concave third mounting groove 107-1 for mounting the third sealing structure. The radial dimension of the third mounting groove 107-1 is smaller than the radial dimension of the first mounting groove 107-2. Therefore, the first sealing structure has a larger contact area with the first channel 107, further optimizing its stability in supporting the loading rod 400 axially.

[0058] The first mounting groove 107-2 and the third mounting groove 107-1 are spaced apart axially, meaning that each mounting groove is separated from the others. Optionally, the axial dimension of the first mounting groove 107-2 is larger than the axial dimension of the third mounting groove 107-1. In this configuration, the third sealing structure is located above the first sealing structure, that is, closer to the accommodating cavity 106. As the first sealing part 111, it needs to withstand pressure from different directions. The arrangement of the third sealing structure helps to optimize the distribution of these pressures and reduce the possibility of deformation of the first sealing structure due to uneven pressure, which could weaken its axial support force on the loading rod 400.

[0059] In the example shown, a fourth sealing structure is provided between the first guide ring and the retaining ring. This fourth sealing structure includes several seals stacked axially. The fourth sealing structure is the same as the first and second sealing structures and will not be described again here. The first channel 107 also has a radially concave fourth mounting groove 107-3, the radial dimension of which is consistent with the radial dimension of the first mounting groove 107-2. This increases the installation strength between the fourth sealing structure and the fourth mounting groove 107-3. The first guide ring ensures the coaxiality of the loading rod 400 and the first channel 107, the retaining ring provides circumferential anti-rotation for the loading rod 400, and the fourth sealing structure is further provided between them. This fourth sealing structure also includes several seals stacked axially.

[0060] By adding a fourth sealing structure between the first guide ring and the retaining ring, the sealing performance of the system is further enhanced, preventing leakage of the pressurized medium from the tiny gap between the loading rod 400 and the channel. Furthermore, the overlapping seals along the axial direction provide additional axial support. This design helps to better distribute the gravitational load of the loading rod 400, improving the overall structural stability and load-bearing capacity.

[0061] In the above embodiments, the radial and axial dimensions of the first mounting groove 107-2, the second mounting groove 104-1c, and the fourth mounting groove 107-3 are all identical. This increases the compatibility of the accessories, allowing them to be used interchangeably within these mounting grooves.

[0062] In the technical solution of this application, in order to drive the loading rod 400 to move axially, the main cylinder 105 is also provided with a first inlet channel 108a and a first outlet channel 108b that are connected to the upper cavity 106-1, and the first inlet channel 108a and the first outlet channel 108b extend radially; it also includes a second inlet channel 109a and a second outlet channel 109b that are connected to the lower cavity 106-2, and the second inlet channel 109a and the second outlet channel 109b extend radially.

[0063] The technical solution of this application utilizes a radially extending channel design to more effectively utilize the space within the accommodating cavity 106, avoiding excessive axial space occupation. The radially extending channel allows for smoother airflow into and out of the upper cavity 106-1 and lower cavity 106-2, reducing airflow resistance caused by channel bending or turning. The radially extending channel also serves as additional structural support, enhancing the structural strength of the accommodating cavity 106 or related components, thereby increasing the pressurization limit of the triaxial ultra-high pressure holding and loading device in this solution.

[0064] It also includes a third inlet channel 110a and a third outlet channel 110b connected to the main cavity 101, which extend radially. This further increases the structural strength of the main cylinder 105. Simultaneously, by providing a fourth and third sealing structure, communication between the main cavity 101 and the lower cavity 106-2 is prevented, ensuring pressure within the main cavity 101.

[0065] In the above embodiment, the first inlet channel 108a, the second inlet channel 109a, and the third inlet channel 110a are axially aligned; the first outlet channel 108b, the second outlet channel 109b, and the third outlet channel 110b are axially aligned; and the first inlet channel 108a and the first outlet channel 108b are at the same height, the second inlet channel 109a and the second outlet channel 109b are at the same height, and the third inlet channel 110a and the third outlet channel 110b are at the same height. That is, the first inlet channel 108a and the first outlet channel 108b are on the same plane, the second inlet channel 109a and the second outlet channel 109b are on the same plane, and the third inlet channel 110a and the third outlet channel 110b are on the same plane.

[0066] Therefore, the technical solution of this application includes three inlet channels and three outlet channels, each equipped with a pressure valve. The channels are evenly spaced circumferentially, meaning there is a 60° interval between any two adjacent circumferential channels.

[0067] During the pressurization process, liquid is injected or discharged into the upper chamber 106-1 and the main chamber 101 to apply or reduce axial and confining pressures on the sample. Liquid or gas is injected into the lower chamber 106-2 via its pressure valve, causing the loading rod 400 to reset. Externally, a pipe connects the upper chamber 106-1 and the main chamber 101 to ensure pressure balance within each chamber. The pressure valve in the lower chamber 106-2 is open, but no liquid is injected or discharged. This triaxial ultra-high pressure holding loading device lays the foundation for conducting triaxial loading tests on high-fidelity samples under ultra-high pressure conditions, thus studying more realistic rock mechanical behavior.

[0068] In the aforementioned embodiments, the upper cover 104 and the main cylinder 105 are connected by threads. Specifically, the upper cover 104 is provided with 12 circumferentially distributed hexagonal head screws for connection with the main cylinder 105. An annular sealing portion 111 is provided at the edge of the upper cover 104 that contacts the upper surface of the main cylinder 105. The sealing portion 111 is distributed around the accommodating cavity 106. Specifically, the sealing portion 111 is located at the corner where the central protrusion of the upper cover 104 meets its edge. The sealing portion 111 has an annular groove on the surface of the upper cover 104 or the cylinder body, and a sealing ring is disposed within the annular groove.

[0069] The lower cover 103 also has a flange structure, identical to that of the upper cover 104. However, the middle portion of the lower cover 103 is not inserted into the main cavity 101, but rather abuts against the lower surface of the main cylinder 105, and its radial dimension matches that of the lower surface of the main cylinder 105. A flange 112 is formed in the middle of the lower cover 103. The flange 112 is embedded in the main cavity 101, thereby limiting the installation position of the main cylinder 105 and the lower cover 103 while forming a radial stop. A sealing portion 111 is also provided on the outer side of the flange 112, that is, at the position where the lower cover 103 contacts the lower surface of the main cylinder 105. The sealing portions 111 are distributed around the main cavity 101, and their structure can be understood with reference to the structure of the sealing portion 111 of the upper cover 104. The lower cover 103 is provided with 16 hexagonal head screws evenly distributed circumferentially for connection with the main cylinder 105. In the two examples above, the number of screws can be chosen by those skilled in the art, and no specific limit is made here.

[0070] In the above embodiments, the overall wall thickness of the cylinder is increased, thereby increasing the pressure bearing capacity of the cylinder. In addition, by adopting the technical solution of this application, unnecessary drilling can be avoided, further increasing the upper limit of the pressure bearing capacity of the cylinder.

[0071] In some other embodiments of this application, the triaxial ultra-high pressure holding and loading device further includes a push rod 200 and a locking structure 300 that can deform radially. The lower cover has a main cavity 101 and a channel 102 that are connected. The push rod 200 can move along the channel 102. The channel 102 extends axially and is disposed on the lower side of the main cavity 101. At this time, the top end of the push rod 200 is used to support the test piece 900. During the loading process, the push rod 200 can be inserted into the channel 102 from bottom to top and push the test piece 900 into and hold it at a set height in the main cavity 101. Of course, if the channel 102 is located on the upper side of the main cavity 101, then the bottom end of the push rod 200 is equipped with the test piece 900. During the feeding process, the push rod 200 is inserted into the channel 102 from top to bottom and pushes the test piece 900 into and fixes it at the set height of the main cavity 101. Similarly, the channel 102 can also be extended in the left and right direction and located on the left or right side of the main cavity 101. These are all within the protection scope of this patent.

[0072] In this embodiment, in order to accommodate and fix the lock structure 300, a portion of the channel 102 is radially recessed to form a groove 102b for accommodating the lock structure 300. The groove 102b has an annular structure, surrounds the outside of the push rod 200, and is spaced from the outer side wall of the push rod 200. The space between the grooves is used to accommodate the lock structure 300 and allow the lock structure 300 to deform radially within the space between the grooves to switch between the unlocked and unlocked positions.

[0073] The groove 102b has a bottom wall 102b-2 and a top wall 102b-1 that are opposite each other along the height direction. The bottom wall 102b-2 and the top wall 102b-1 extend radially. A side wall 102b-3 is provided between the bottom wall 102b-2 and the top wall 102b-1. The side wall 102b-3 extends axially and is radially opposite to the groove opening. The groove opening penetrates the wall of the channel 102, thereby realizing the connection between the groove 102b and the channel 102.

[0074] The locking structure 300 includes a plurality of petals 301, which may be two, three or more; in an example shown in the figure, the number of petals 301 is eight. The plurality of petals 301 are elastically connected circumferentially and arranged around the push rod 200.

[0075] The locking structure 300 includes a closed-loop spring assembly. Under the action of the spring assembly, the individual petals 301 are closely distributed circumferentially. The spring assembly includes at least one spring, thereby generating a spring force on each petal 301 along its circumferential direction. Each petal 301 has an axially opposite head end 301-1 and a tail end 301-2. The end faces of both the head end 301-1 and the tail end 301-2 extend horizontally. The petal 301 has an inclined structure, with its inner surface 301a forming a 75° slope and its outer surface 301b forming a 74° slope. Other inclination angles are also possible and are not specifically limited here. In a specific example, the petals 301 form a trapezoidal frustum structure, the middle of which is hollow, and the cross-sectional shape of its middle part along the axial direction is trapezoidal. Both the inner surface 301a and the outer surface 301b of the petal 301 are curved surfaces. Of course, the inner surface 301a and the outer surface 301b of the petal 301 can also be straight surfaces, or the inner surface 301a can be straight surfaces and the outer surface 301b can be curved surfaces, or the outer surface 301b can be straight surfaces and the inner surface 301a can be curved surfaces.

[0076] The locking structure 300 is located within the groove 102b. The tail end 301-2 abuts against the groove wall at least axially, meaning the outer surface 301b of the tail end 301-2 presses against the bottom wall 102b-2 of the groove. The head end 301-1 can be radially flipped outwards to the unlocked position or radially flipped inwards to the locked position. The push rod 200 includes a stop portion 202. The push rod 200 includes a rod body and a stop portion 202 formed by the radial outer edge of the rod body. The stop portion 202 matches the radial dimension of the channel 102, while the radial dimension of the rod body is smaller than the radial dimension of the channel 102. The rod body itself can be a constant diameter structure or its radial dimension can vary in a stepped manner; here, it is sufficient that the radial dimension of the stop portion 202 is the maximum value of the radial dimension of the push rod 200. Furthermore, the stop portion 202 is located in the middle of the rod body. Here, "middle" does not specifically refer to the axial midpoint of the rod body, but rather to any area between the top and bottom ends of the rod body.

[0077] The locking end 301-1 abuts axially against the stop part 202. The specific rotation method of the flap 301 will be explained in detail below.

[0078] By adopting the technical solution of this application, a locking structure 300 is set in the channel 102 to form an axial stop on the push rod 200, thereby ensuring the stability and reliability of the axial position of the push rod 200 and improving the accuracy and durability of the entire experimental system.

[0079] In an optional example, the tail end 301-2 abuts radially against a portion of the groove wall of the groove 102b. This secures the locking structure 300 within the groove 102b while maintaining its radial position within the groove 102b. Specifically, at least one spring in the spring assembly can be used to achieve this radial abutment. Specifically, the spring assembly includes a tail spring 303, which is disposed on the inner surface 301a of the tail end 301-2 to apply an outward elastic force to the flap 301. The tail spring 303 is disposed on the inner surface 301a of the flap 301 near the tail end 301-2, and by providing the tail spring 303, the tail end 301-2 of the flap 301 is radially pressed against the groove wall using a mechanical structure. Of course, the switching between the unlocked and locked positions can also be achieved if the tail end 301-2 does not abut against the groove side wall 102b-3 of the groove 102b. For example, a magnetic suction element can be set in a groove to generate radial magnetic force on the petal 301, or a positioning groove can be opened in the bottom wall 102b-2 of the groove so that the tail end 301-2 of the petal 301 can be inserted into the positioning groove. In addition, besides using the tail spring 303 to drive the petal 301 to radially press against the groove side wall 102b-3, an electromagnetic drive element can also be used.

[0080] The spring assembly also includes a closed-loop first spring 302, which is disposed on the outer wall of the petal portion 301 near the first end 301-1 to apply an inward elastic force to the petal portion 301. In this way, the tail spring 303 is subjected to an outward elastic force by the inner side surface 301a of the petal portion 301, and the bottom of the petal portion 301 always remains in an outwardly expanded state and abuts against the groove side wall 102b-3. At this time, the tail spring 303 is still in a deformed state. The first spring 302, located on the outer side surface 301b of the petal portion 301, applies an inward elastic force to drive the first end 301-1 near the push rod 200 so that the axial projection plane of the first end 301-1 can partially coincide with the projection range of the stop portion 202, thereby abutting against the stop portion 202 in the axial direction. In this way, the first spring 302 is driven to deform during the radial outward rotation in the unlocked position. After the external force disappears, it can automatically rotate inward, thus realizing the self-locking of the lock structure 300.

[0081] To secure the head spring 302 and tail spring 303, a C-shaped annular mounting groove 304 is provided on the inner side 301a and outer side wall of the petal portion 301. The opening of the mounting groove 304 is used to stop the head spring 302 and tail spring 303 within the mounting groove 304 to prevent them from popping out. During the flipping process of the petal portion 301, both the head spring 302 and tail spring 303 can rotate relative to the mounting groove 304, thereby preventing the mounting groove 304 from interfering with the deformation of the head spring 302 and tail spring 303.

[0082] In the example shown, the channel 102 penetrates the bottom surface of the cylinder 100 to form an insertion port 102a. The bottom of the locking structure 300, i.e., the tail end 301-2 of each petal 301, faces the side where the opening is located, while the head end 301-1 faces the side where the main cavity 101 is located. The inner diameter of the bottom of the locking structure 300 is larger than the inner diameter of the head end 301-1 of the locking structure 300, and is also larger than the inner diameter of the stop part 202.

[0083] The following is a detailed description of the feeding process of the triaxial ultra-high pressure holding and loading device in this application, as well as the adaptation method between the push rod 200 and the lock structure 300 during the testing process.

[0084] Feeding process

[0085] During the loading process, the test piece 900 is first installed on the top of the rod body. Then, the radial dimension of the test piece 900 is smaller than the inner diameter of the stop part 202 and smaller than the inner diameter of the first end 301-1 of the lock structure 300. In the axial direction, the portion of the rod body located near the main cavity 101 of the stop portion 202 (as shown in the example, the portion of the rod body located on the upper side of the stop portion 202 is defined as the front rod segment 201; conversely, the portion of the rod body located away from the main cavity 101 of the stop portion 202, i.e., the portion of the rod body located on the lower side of the stop portion 202, is defined as the rear rod segment 203) has a radial dimension smaller than that of the stop portion 202. This ensures that during the insertion of the lock structure 300, the stop portion 202 first contacts the inner surface 301a of the flap portion 301, meaning that neither the test piece 900 nor the front rod segment 201 will contact the inner surface 301a of the flap portion 301. The inner diameter of the tail end 301-2 is greater than or equal to the radial dimension of the channel 102. Thus, in the unlocked state, the stop portion 202 can move along the channel 102 through the middle of the tail end 301-2 for loading operations.

[0086] Specifically, the stop 202 first enters the tail of the lock structure 300. The side edge of the top of the stop 202 abuts against the inner side surface 301a of the tail of the lock structure 300. As the stop 202 is further inserted, the flap 301 is driven by the stop 202 to flip outward to the unlocked position. In the unlocked position, the inner diameter of the tip 301-1 of the flap 301 is large enough to allow the stop 202 to pass through.

[0087] After the stop portion 202 passes through the first end 301-1 of the plate portion, under the drive of the first elastic member, the petal portion 301 flips inward to reset, or flips inward to abut radially against the side wall of the portion of the push rod 200 located away from the central cavity of the stop portion 202, that is, against the rear rod section 203 of the push rod 200. At the same time, under the action of gravity, the push rod 200 presses down to the end face of the first end 301-1 of each petal portion 301 to form a lock, completing the loading operation.

[0088] As one implementation method, the insertion process of the push rod 200 can be performed manually or electrically. In the electrically inserted method, a drive component and an adapter pipe 200-1 are included to move the push rod 200. The drive component can be a motor, hydraulic press, etc. The adapter pipe 200-1 is fitted onto the rear rod section 203 and is detachably connected to the rear rod section 203, specifically through a threaded connection. The radial dimension of the adapter pipe 200-1 is smaller than the radial dimension of the channel 102 so that the adapter pipe 200-1 can also be inserted into the channel 102. The adapter pipe 200-1 is directly or indirectly connected to the output end of the drive component, thereby connecting the push rod 200 and the drive component through the adapter pipe 200-1. Optionally, the edge of the adapter pipe 200-1 near the top of the stop portion 202 has a 45° chamfer.

[0089] After the material loading operation is completed, the test piece 900 can be tested. During this process, the locking structure 300 always keeps the push rod 200 locked.

[0090] In the aforementioned embodiment, the end of the stop portion 202 near the main cavity 101 is provided with a second inclined surface to adapt to the inner wall of the flap portion 301. By providing the second inclined surface, the resistance of the stop portion 202 in driving the flap portion 301 to flip is reduced, and the unlocking tube 200-2 can also be introduced into the inner side of the lock structure 300.

[0091] The unlocking method and material cutting operation of lock structure 300 are explained in detail below.

[0092] In order to unlock the lock structure 300 for unloading after testing, either mechanical unlocking or electronic unlocking can be used. In electronic unlocking, an electromagnetic drive can be used to drive the petal 301 to flip outward again to the unlock position. Those skilled in the art can also choose other electric unlocking methods as needed.

[0093] The mechanical unlocking method is described here with a specific embodiment. It also includes an unlocking tube 200-2 that can be inserted into the channel 102. The unlocking tube 200-2 can be sleeved on the outside of the push rod 200, and the outer diameter of the unlocking tube 200-2 matches the outer diameter of the stop portion 202. By providing the unlocking tube 200-2, the flap 301 can be driven to flip outward during the insertion of the unlocking tube 200-2 into the channel 102, thereby switching from the locked position to the unlocked position.

[0094] Specifically, the inner diameter of the unlocking tube 200-2 is larger than that of the rear rod section 203 and smaller than that of the channel 102. During the loading and testing process, the rear rod section 203 and the channel 102 are radially spaced apart, and the unlocking tube 200-2 can be inserted into this gap. The outer diameter of the unlocking tube 200-2 is consistent with the outer diameter of the stop section 202.

[0095] Optionally, the end of the unlocking tube 200-2 is provided with a first inclined surface adapted to fit the inner wall of the flap 301. The radial dimension of the first inclined surface increases from the side closer to the main cavity 101 to the side farther away from the main cavity 101. By providing the first inclined surface, the resistance of the unlocking tube 200-2 in driving the flap 301 to flip is reduced, and the unlocking tube 200-2 can also be guided into the inner side of the lock structure 300. As an option, the first inclined surface is 75°, but other inclination angles are also possible, which can be selected by those skilled in the art.

[0096] The unlocking and unloading methods of lock structure 300 will be further explained below.

[0097] Material feeding process

[0098] Separate the adapter tube 200-1 from the rear rod section 203 and unload it from the channel 102. Then, put the unlocking tube 200-2 on the outside of the rear rod section 203 and insert it into the gap between the rear rod section 203 and the channel 102. Continue to push it upward until it abuts against the inner side 301a of the tail end 301-2 of the petal 301. As the unlocking tube 200-2 is further inserted axially, the petal 301 is driven to turn outward until the tube end face of the unlocking tube 200-2 abuts axially against the end face of the stop part 202. At this time, pull out the push rod 200 along the direction of the push-out channel 102. The stop part 202 and the unlocking tube 200-2 can then be withdrawn from the locking structure 300 together, completing the unloading operation.

[0099] In the above embodiments, at least a portion of the outer side wall of the stop 202 is sealed to the wall of the channel. This seals the main cavity 101. Specifically, the stop 202 and the retaining ring 202a combine to form an annular receiving groove for accommodating the rubber sealing ring. The outer side wall of the retaining ring 202a is radially the same as that of the stop 202, and the outer side wall of the retaining ring 202a is inclined at 75°.

[0100] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A triaxial ultra-high pressure holding and loading device, characterized in that, The device includes an upper cover (104), a loading rod (400), and a main cylinder (105). The main cylinder (105) has a spaced-apart main cavity (101) and a receiving cavity (106). The main cavity (101) and the receiving cavity (106) are connected by a first channel (107). The upper cover (104) is used to seal the receiving cavity (106). The upper cover (104) is also provided with a second channel (104-1). The loading rod (400) passes through the second channel (104-1), the receiving cavity (106), and the first channel (107) in sequence to the main cavity (101). The portion of the loading rod (400) located within the accommodating cavity (106) is provided with a plug (401), and the plug (401) is sealed and adapted to the cavity wall of the accommodating cavity (106); The plug (401) divides the accommodating cavity (106) into an upper cavity (106-1) and a lower cavity (106-2); From top to bottom, the first channel (107) is sequentially provided with a first sealing structure, a first guide ring and a retaining ring for adapting to the loading rod (400); the second channel (104-1) is sequentially provided with a dustproof component, a second guide ring and a second sealing structure for adapting to the loading rod (400); The first sealing structure includes a plurality of seals stacked axially; and / or, the second sealing structure includes a plurality of seals stacked axially.

2. The triaxial ultra-high pressure holding and loading device according to claim 1, characterized in that, A portion of the first channel (107) is radially recessed to form a first mounting groove (107-2), and the first sealing structure is located within the first mounting groove (107-2); A portion of the second channel (104-1) is radially recessed to form a second mounting groove (104-1c), and the second sealing structure is located within the second mounting groove (104-1c).

3. The triaxial ultra-high pressure holding and loading device according to claim 2, characterized in that, The first channel (107) is also provided with a third sealing structure, which includes a single sealing element and is located axially above the first sealing structure.

4. The triaxial ultra-high pressure holding and loading device according to claim 3, characterized in that, The first channel (107) is also provided with a radially concave third mounting groove (107-1) for mounting the third sealing structure; The radial dimension of the third mounting groove (107-1) is smaller than the radial dimension of the first mounting groove (107-2).

5. The triaxial ultra-high pressure holding and loading device according to claim 4, characterized in that, A fourth sealing structure is also provided between the first guide ring and the retaining ring, the fourth sealing structure comprising a plurality of sealing elements stacked together along the axial direction.

6. The triaxial ultra-high pressure holding and loading device according to claim 2, characterized in that, The first channel (107) is also provided with a fourth mounting groove (107-3) that is radially concave, and the radial dimension of the fourth mounting groove (107-3) is consistent with the radial dimension of the first mounting groove (107-2).

7. The triaxial ultra-high pressure holding and loading device according to claim 6, characterized in that, The radial and axial dimensions of the first mounting groove (107-2), the second mounting groove (104-1c), and the fourth mounting groove (107-3) are all the same.

8. The triaxial ultra-high pressure holding and loading device according to any one of claims 1-7, characterized in that, The main cylinder (105) is also provided with a first inlet channel (108a) and a first outlet channel (108b) that communicate with the upper cavity (106-1), and the first inlet channel (108a) and the first outlet channel (108b) extend radially. It also includes a second inlet channel (109a) and a second outlet channel (109b) communicating with the lower cavity (106-2), the second inlet channel (109a) and the second outlet channel (109b) extending radially.

9. The triaxial ultra-high pressure holding and loading device according to claim 8, characterized in that, It also includes a third inlet channel (110a) and a third outlet channel (110b) communicating with the main cavity (101), the third inlet channel (110a) and the third outlet channel (110b) extending radially.

10. The triaxial ultra-high pressure holding and loading device according to claim 9, characterized in that, The first inlet channel (108a), the second inlet channel (109a), and the third inlet channel (110a) are axially aligned; the first outlet channel (108b), the second outlet channel (109b), and the third outlet channel (110b) are axially aligned. Furthermore, the first entry channel (108a) and the first discharge channel (108b) are located at the same height, the second entry channel (109a) and the second discharge channel (109b) are located at the same height, and the third entry channel (110a) and the third discharge channel (110b) are located at the same height.

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