A liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device

Abstract

The utility model provides a kind of liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device, belong to low temperature brittle fracture sample preparation equipment technical field, including experimental bin, horizontal clamping mechanism and horizontal two-way stretching execution mechanism;Horizontal clamping mechanism includes first clamping head and second clamping head, two clamping heads are mirror image symmetry about the vertical plane between two;Lead screw is sequentially set first thread segment and second thread segment of equal lead and opposite rotation along axial direction, respectively with first nut block and second nut block slidingly connected in linear guide rail are threadedly connected, to drive first clamping head and second clamping head along horizontal axis equal speed reverse movement;The utility model has the beneficial effect that: using horizontal placement mode makes film surface perpendicular to gravity direction, avoids interlayer shear deformation in freezing process;Adopt two-way symmetric stretching mode to ensure that sample is coaxial brittle fracture along axial direction, improves the fidelity of brittle fracture surface and the repeatability of sample preparation between batches.

Description

Technical Field

[0001] This utility model belongs to the technical field of low-temperature brittle fracture sample preparation equipment, and relates to a horizontal coaxial brittle fracture sample preparation device in a liquid nitrogen environment. Background Technology

[0002] The interface structure and cross-sectional morphology of thin film materials are crucial for evaluating their performance. For multilayer composite films, microporous functional films, and surface coatings, the cross-sectional morphology typically requires observation and analysis using techniques such as scanning electron microscopy (SEM). The reliability of the observation results largely depends on the quality of the cross-sectional sample preparation. If the cross-section is subjected to compression or interlayer displacement during preparation, the original characteristics such as the micropore shape and interlayer interfaces will be destroyed, making it difficult to reflect the true state of the sample. To obtain a faithful cross-section, the sample is usually cooled to an embrittled state in a liquid nitrogen environment and then broken axially, using low-temperature brittle fracture to expose the undeformed internal structure.

[0003] Current methods for preparing cryogenic brittle fracture samples often employ a vertical liquid nitrogen tank combined with a vertical suspension clamping technique. This involves vertically suspending the membrane sample and immersing it in liquid nitrogen for cooling, then applying tension from the top or bottom to induce fracture. In this vertical suspension structure, the membrane sample is placed vertically with its surface parallel to the direction of gravity. During the cooling and freezing process, the flexible membrane layers are continuously pulled along the membrane surface by their own weight, causing relative slippage between layers. This leads to the collapse and deformation of the microporous structure, and the membrane sample's interface deviates from its true state before complete freezing.

[0004] Furthermore, most existing tensile loading mechanisms are based on single-end drive or cantilever configurations, meaning one end of the sample is fixed while the other end is subjected to force. Under this loading method, the forces acting on the two ends of the sample are asymmetrical. Combined with the assembly clearances and off-center loading effects inherent in the kinematic pairs, additional bending moments are easily introduced into the sample. Under the action of these bending moments, the sample deflects, and the fracture direction deviates from the tensile axis, resulting in an inclined cross-section. This introduces systematic errors into the quantitative evaluation of interfacial bonding performance.

[0005] In summary, existing low-temperature brittle fracture sample preparation equipment has two main problems: First, the parallelism between the film surface and the direction of gravity causes interlayer shearing during the freezing process, which destroys the original structure of the interface. Second, single-end drive leads to asymmetrical forces at both ends of the sample, introducing bending moments, causing the sample to deflect and form oblique fracture surfaces. Both of these factors together restrict the fidelity of the brittle fracture surface and the repeatability of sample preparation between batches. Utility Model Content

[0006] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device.

[0007] The objective of this utility model can be achieved through the following technical solution: a liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device, comprising: An experimental chamber configured to contain liquid nitrogen and samples; A horizontal clamping mechanism, comprising a first clamping head and a second clamping head, both located within the experimental chamber, wherein the clamping openings of the first clamping head and the second clamping head are located on the same horizontal axis, and the first clamping head and the second clamping head are arranged in a mirror-symmetrical manner about the vertical plane between them; A horizontal bidirectional tension actuator, comprising a servo motor, a linear guide, and a lead screw; The linear guide rail is slidably connected with a first nut block and a second nut block, and the sliding trajectory of the first nut block and the sliding trajectory of the second nut block are both parallel to the horizontal axis. The servo motor is motion-coupled with the lead screw. The lead screw is provided with a first threaded section and a second threaded section arranged sequentially along its axial direction. The lead of the first threaded section and the second threaded section are equal and opposite in direction. The first threaded section is threadedly connected to the first nut block, and the second threaded section is threadedly connected to the second nut block. The first nut block is provided with a first connecting rod, which passes through the wall of the experimental chamber and is fixedly connected to the first clamping head; the second nut block is provided with a second connecting rod, which passes through the wall of the experimental chamber and is fixedly connected to the second clamping head. The first clamping head and the second clamping head are configured to be driven by the lead screw to move in opposite directions at the same speed along the horizontal axis.

[0008] Preferably, the horizontal bidirectional tension actuator further includes a reducer, the output shaft of the servo motor is connected to the input shaft of the reducer, and the output shaft of the reducer is connected to the lead screw.

[0009] Preferably, the experimental chamber has a first through hole on the side wall corresponding to the first clamping head, and the experimental chamber has a second through hole on the side wall corresponding to the second clamping head. The first connecting rod passes through the first through hole, the second connecting rod passes through the second through hole, and sealing rings are provided between the first connecting rod and the first through hole, and between the second connecting rod and the second through hole.

[0010] Preferably, the system also includes a liquid nitrogen storage chamber and a liquid nitrogen delivery mechanism, wherein the input end of the liquid nitrogen delivery mechanism is connected to the liquid nitrogen storage chamber, the output end of the liquid nitrogen delivery mechanism is connected to the experimental chamber, and the liquid nitrogen delivery mechanism is configured to deliver liquid nitrogen from the liquid nitrogen storage chamber to the experimental chamber.

[0011] Preferably, the liquid nitrogen delivery mechanism includes a liquid nitrogen replenishment pump, a solenoid valve, and a replenishment pipeline. The two ends of the replenishment pipeline are respectively connected to the experimental chamber and the liquid nitrogen storage chamber. The liquid nitrogen replenishment pump and the solenoid valve are both connected in series on the replenishment pipeline.

[0012] Preferably, the experimental chamber also includes a controller, and a liquid level probe is installed inside the experimental chamber. The liquid level probe, the liquid nitrogen replenishment pump, the solenoid valve, and the servo motor are all electrically connected to the controller.

[0013] Preferably, a weighing sensor is provided at the bottom of the liquid nitrogen storage chamber, and the weighing sensor is electrically connected to the controller.

[0014] Preferably, the experimental chamber has an opening for taking out and placing samples, and the experimental chamber is equipped with a cover for controlling the opening and closing of the opening. A chip collection bin is installed at the bottom of the experimental chamber, and the chip collection bin is provided with a waste inlet and an exhaust port. A cleaning port is provided on the bottom wall of the experimental chamber, and the chip collection bin is connected to the cleaning port of the experimental chamber through the waste inlet. A valve is provided between the waste inlet and the cleaning port.

[0015] Preferably, it also includes a linear drive element and a magnetic coupling element. The magnetic coupling element is connected to the linear drive element and is displaced by the linear drive element. A slidable scraper is installed on the inner bottom surface of the experimental chamber. The scraper is in contact with the inner bottom surface of the experimental chamber. The cleaning port is located at the end of the movement path of the scraper. A magnetic force-receiving part is provided at one end of the scraper close to the side wall of the experimental chamber. The magnetic coupling element is magnetically coupled to the magnetic force-receiving part of the scraper through the side wall of the experimental chamber.

[0016] Preferably, the liquid nitrogen storage chamber includes an outer shell and an inner liner, the inner liner being disposed inside the outer shell, and a vacuum insulation interlayer being formed between the inner liner and the outer shell, the vacuum insulation interlayer being lined with an insulation layer made of alternating layers of aluminized polyester film and glass fiber paper.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. The horizontal placement method ensures that the film surface is perpendicular to the direction of gravity, avoiding interlayer shear deformation during the freezing process; the bidirectional symmetrical loading method eliminates the bending moment introduced by single-end drive, ensuring that the sample fractures coaxially along the axial direction, improving the fidelity of the brittle fracture surface and the repeatability of sample preparation between batches.

[0018] 2. The liquid nitrogen replenishment pump is used to provide power for liquid nitrogen delivery, and the solenoid valve is used to control the opening and closing of the replenishment pipeline. This allows the liquid nitrogen delivery to be controlled according to the actual replenishment needs, reducing the continuous flow of liquid nitrogen in non-replenishment states and ensuring that replenishment disturbances avoid the sample's breakage-sensitive phase.

[0019] 3. It can utilize the pressure generated by the natural evaporation of liquid nitrogen to assist in chip removal, reducing the need to open the experimental chamber during the chip removal process; therefore, it is not necessary to drain all the liquid nitrogen in the experimental chamber, nor is it necessary to wait for the experimental chamber to heat up before cleaning, which is conducive to maintaining the low-temperature environment required for subsequent sample preparation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram showing the connection relationship between the experimental chamber, the horizontal clamping mechanism, the horizontal bidirectional tensioning actuator, and the liquid nitrogen storage chamber of this utility model.

[0021] Figure 2 This is a schematic diagram showing the connection relationship between the horizontal clamping mechanism and the horizontal bidirectional tensioning actuator of this utility model.

[0022] Figure 3 This is a schematic diagram of the internal structure of the brittle fracture sample preparation device of this utility model.

[0023] Figure 4 This is a schematic diagram of the magnetic coupling component and scraper of this utility model.

[0024] Figure 5 This is an isometric view of the brittle fracture sample preparation device of this utility model.

[0025] In the diagram, 100 is the experimental chamber; 110 is the liquid level probe; 120 is the chamber cover; 130 is the cleaning port; 140 is the scraper; 141 is the magnetic force-bearing part; 210 is the first clamping head; 220 is the second clamping head; 300 is the servo motor; 310 is the reducer; 400 is the linear guide rail; 410 is the first nut block; 411 is the first connecting rod; 420 is the second nut block; 421 is the second connecting rod; 500 is the lead screw; 510 is the first threaded section; 520 is the second threaded section; 600 is the liquid nitrogen storage chamber; 700 is the liquid replenishment pipeline; 800 is the chip collection chamber; 810 is the valve; 900 is the linear drive element; and 910 is the magnetic coupling element. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0027] like Figures 1 to 5As shown, a horizontal coaxial brittle fracture sample preparation device in a liquid nitrogen environment includes an experimental chamber 100, a horizontal clamping mechanism, and a horizontal bidirectional tensile actuator. The experimental chamber 100 is configured to contain liquid nitrogen and a sample. The horizontal clamping mechanism includes a first clamping head 210 and a second clamping head 220, both located within the experimental chamber 100. The clamping openings of the first clamping head 210 and the second clamping head 220 are located on the same horizontal axis, and the first clamping head 210 and the second clamping head 220 are mirror-symmetrically arranged about their midline. The horizontal bidirectional tensile actuator includes a servo motor 300, a linear guide rail 400, and a lead screw 500. The linear guide rail 400 is slidably connected to a first nut block 410 and a second nut block 420, and the sliding trajectories of the first nut block 410 and the second nut block 420 are... Parallel to the horizontal axis; the servo motor 300 is motion-coupled with the lead screw 500, which is provided with a first threaded section 510 and a second threaded section 520 arranged sequentially along its axial direction. The lead of the first threaded section 510 and the second threaded section 520 are equal and opposite in direction of rotation. The first threaded section 510 is threadedly connected to the first nut block 410, and the second threaded section 520 is threadedly connected to the second nut block 420. The first nut block 410 is provided with a first connecting rod 411, which passes through the wall of the experimental chamber 100 and is fixedly connected to the first clamping head 210. The second nut block 420 is provided with a second connecting rod 421, which passes through the wall of the experimental chamber 100 and is fixedly connected to the second clamping head 220. The first clamping head 210 and the second clamping head 220 are configured to be driven by the lead screw 500 to move in opposite directions at the same speed along the horizontal axis.

[0028] In this embodiment, the experimental chamber 100 can be made of a cryogenic metal material, and its interior forms an experimental space for containing liquid nitrogen and samples. The first clamping head 210 and the second clamping head 220 can be opposing flat-mouth clamps with their clamping openings facing each other, used to clamp both ends of the sample. The clamping working surfaces of the clamping openings can be provided with anti-slip textures to improve the clamping stability of the sample under cryogenic conditions.

[0029] The linear guide 400 can be made up of two parallel linear guides 400. The first nut block 410 and the second nut block 420 are slidably engaged with the linear guide 400 through sliders. The linear guide 400 is used to limit the movement of the first nut block 410 and the second nut block 420 in a non-horizontal direction and to limit the deflection of the nut blocks, so that the two nut blocks can move stably in a direction parallel to the horizontal axis.

[0030] When the servo motor 300 drives the lead screw 500 to rotate, the first threaded section 510 drives the first nut block 410 to move in one direction, and the second threaded section 520 synchronously drives the second nut block 420 to move in the opposite direction. Since the lead of the first threaded section 510 and the second threaded section 520 is equal, the moving speed of the first nut block 410 and the second nut block 420 is equal. The first connecting rod 411 and the second connecting rod 421 respectively drive the first clamping head 210 and the second clamping head 220 to move in opposite directions at the same speed, applying horizontal pulling forces in opposite directions from both ends of the sample.

[0031] The core of this implementation lies in achieving synchronous, counter-clockwise mechanical movement of the two clamping heads through two threaded segments with opposite directions and equal leads on the same lead screw 500. When the sample is located between the two clamping heads, the sample center will not shift to one side due to the movement of one clamping head. The two clamping heads move along the same horizontal axis, allowing the tensile load to be transmitted along the sample length. The horizontally arranged clamping heads enable the sample to be frozen and fractured in a horizontal posture in liquid nitrogen. For thin film samples, the direction of gravity is mainly perpendicular to the sample plane, which helps to reduce the interlayer relative movement caused by suspension forces during the freezing process. The linear guide rail 400 and the lead screw 500 transmission structure together restrict the movement direction of the clamping heads, which helps to reduce the influence of eccentric loads and additional bending moments on the fracture surface.

[0032] With the above structure, the sample can be subjected to horizontal, coaxial and symmetrical tensile forces in a liquid nitrogen environment, thereby reducing gravity interference, overall translation caused by unilateral drive and bending deformation caused by off-center loading.

[0033] Based on the above embodiments, the horizontal bidirectional tension actuator also includes a reducer 310, the output shaft of the servo motor 300 is connected to the input shaft of the reducer 310, and the output shaft of the reducer 310 is connected to the lead screw 500.

[0034] In this embodiment, the reducer 310 can be a planetary reducer 310; the power output by the servo motor 300 is transmitted to the lead screw 500 through the reducer 310. The reducer 310 is used to reduce the speed of the lead screw 500 and increase the output torque of the lead screw 500, so that the lead screw 500 can stably drive the first nut block 410 and the second nut block 420 to move at a lower speed.

[0035] Based on the above implementation method, the experimental chamber 100 is provided with a first through hole on the side wall corresponding to the first clamping head 210, and the experimental chamber 100 is provided with a second through hole on the side wall corresponding to the second clamping head 220. The first connecting rod 411 passes through the first through hole, and the second connecting rod 421 passes through the second through hole. Sealing rings are provided between the first connecting rod 411 and the first through hole, and between the second connecting rod 421 and the second through hole.

[0036] In this embodiment, the first through hole and the second through hole are located on two opposite side walls of the experimental chamber 100, respectively. The first connecting rod 411 and the second connecting rod 421 can reciprocate horizontally within the corresponding through holes. A sealing ring is installed between the connecting rod and the wall of the through hole to form a dynamic sealing structure. The sealing ring can be a polytetrafluoroethylene (PTFE) sealing ring, used to reduce the escape of liquid nitrogen vapor from the through holes and to reduce the entry of external heat into the experimental chamber 100 through the through holes.

[0037] like Figures 1 to 3 , Figure 5 As shown, based on the above embodiment, it also includes a liquid nitrogen storage chamber 600 and a liquid nitrogen conveying mechanism. The input end of the liquid nitrogen conveying mechanism is connected to the liquid nitrogen storage chamber 600, and the output end of the liquid nitrogen conveying mechanism is connected to the experimental chamber 100. The liquid nitrogen conveying mechanism is configured to convey liquid nitrogen in the liquid nitrogen storage chamber 600 to the experimental chamber 100.

[0038] In this embodiment, the liquid nitrogen storage tank 600 is used to store the liquid nitrogen required for replenishment, and the liquid nitrogen storage tank 600 is connected to the experimental chamber 100 through a liquid nitrogen delivery mechanism. When the liquid nitrogen level in the experimental chamber 100 drops, the liquid nitrogen delivery mechanism replenishes the liquid nitrogen in the liquid nitrogen storage tank 600 into the experimental chamber 100.

[0039] The liquid nitrogen storage chamber 600 and the liquid nitrogen delivery mechanism form an independent liquid replenishment path, which can replenish liquid nitrogen without frequently opening the experimental chamber 100, thereby reducing the entry of external heat and airflow into the experimental chamber 100 during manual liquid replenishment.

[0040] Based on the above embodiments, the liquid nitrogen delivery mechanism includes a liquid nitrogen replenishment pump, a solenoid valve, and a replenishment pipeline 700. The two ends of the replenishment pipeline 700 are connected to the experimental chamber 100 and the liquid nitrogen storage chamber 600, respectively. The liquid nitrogen replenishment pump and the solenoid valve are both connected in series on the replenishment pipeline 700.

[0041] In this embodiment, a liquid nitrogen replenishment pump is used to provide power for liquid nitrogen delivery, and a solenoid valve is used to control the opening and closing of the replenishment pipeline 700. During replenishment, the solenoid valve opens, the liquid nitrogen replenishment pump operates, and liquid nitrogen is delivered from the liquid nitrogen storage chamber 600 to the experimental chamber 100 via the replenishment pipeline 700. In non-replenishment mode, the solenoid valve closes to cut off the liquid nitrogen delivery channel.

[0042] Based on the above implementation method, a controller is also included. A liquid level probe 110 is installed in the experimental chamber 100. The liquid level probe 110, liquid nitrogen replenishment pump, solenoid valve and servo motor 300 are all electrically connected to the controller.

[0043] In this embodiment, the liquid level probe 110 is used to detect the liquid nitrogen level in the experimental chamber 100. The controller can be a programmable controller, an embedded controller, or an industrial computer. The controller acquires the liquid level signal from the liquid level probe 110, and simultaneously acquires the speed and acceleration signals of the servo motor 300. The speed and acceleration signals of the servo motor 300 can be fed back to the controller by the servo driver. Based on the liquid nitrogen level and the motion state of the servo motor 300, the controller controls the start and stop of the liquid nitrogen replenishment pump and the opening and closing of the solenoid valve.

[0044] When the servo motor 300 is in the acceleration or deceleration phase, the controller keeps the solenoid valve closed, preventing liquid replenishment to the experimental chamber 100. When the servo motor 300 is stationary or running at a constant speed, and the liquid level probe 110 detects that the liquid nitrogen level is lower than the preset threshold, the controller opens the solenoid valve and controls the liquid nitrogen replenishment pump to replenish liquid to the experimental chamber 100.

[0045] It should be noted that the liquid replenishment control is not solely based on the liquid level; it also establishes an interlock relationship with the motion state of the servo motor 300. When the gripper head is accelerating or decelerating, the stress state of the sample is changing. The liquid replenishment action may cause liquid nitrogen flow, liquid surface fluctuations, and local temperature fluctuations, affecting the formation of the brittle fracture interface of the sample. The controller restricts the liquid replenishment action to the time period when the gripper head is stationary or moving at a constant speed, so that the liquid replenishment disturbance avoids the fracture-sensitive stage of the sample.

[0046] Through the above control mechanism, the experimental chamber 100 can be replenished with liquid nitrogen, and the impact of the replenishment process on the brittle fracture conditions of the sample is reduced, which is conducive to maintaining a relatively consistent liquid nitrogen environment and loading conditions in each sample preparation process.

[0047] Based on the above implementation method, a weighing sensor is installed at the bottom of the liquid nitrogen storage chamber 600, and the weighing sensor is electrically connected to the controller.

[0048] In this embodiment, the liquid nitrogen storage tank 600 is mounted on the support of the weighing sensor. The weighing sensor detects the weight of the liquid nitrogen storage tank 600 and the liquid nitrogen inside it, and sends the weight signal to the controller. The controller determines the remaining liquid nitrogen in the liquid nitrogen storage tank 600 based on the weight signal. When the weight is lower than a preset threshold, the controller outputs a liquid nitrogen shortage warning message.

[0049] like Figures 1 to 5As shown, based on the above-described embodiment, the experimental chamber 100 is provided with a sample loading and unloading port, and the experimental chamber 100 is equipped with a chamber cover 120 for controlling the opening and closing of the loading and unloading port. A chip collection chamber 800 is installed at the bottom of the experimental chamber 100. The chip collection chamber 800 is provided with a waste inlet and an exhaust port. A cleaning port 130 is provided on the bottom wall of the experimental chamber 100. The chip collection chamber 800 is connected to the cleaning port 130 of the experimental chamber 100 through the waste inlet. A valve 810 is provided between the waste inlet and the cleaning port 130.

[0050] In this embodiment, the loading / unloading port can be located at the top of the experimental chamber 100. The chamber cover 120 can be made of a permanent magnet plate, which is magnetically connected to the metal mating parts around the loading / unloading port for quick closure. The chip collection chamber 800 is located at the bottom of the experimental chamber 100. A chip discharge channel is formed between the cleaning port 130 and the waste inlet. The valve 810 can be a cryogenic ball valve. When the valve 810 is closed, the chip discharge channel between the experimental chamber 100 and the chip collection chamber 800 is disconnected. When the valve 810 is open, liquid nitrogen and debris in the experimental chamber 100 can flow into the chip collection chamber 800 through the cleaning port 130.

[0051] After the sample breaks, the debris settles at the bottom of the experimental chamber 100. During debris removal, the chamber cover 120 is closed, creating a relatively sealed space within the experimental chamber 100. Residual liquid nitrogen within the chamber evaporates naturally, causing the pressure inside to gradually increase. When valve 810 is opened, the pressure within the experimental chamber 100 forces the liquid nitrogen, carrying the debris, through the cleaning port 130 into the debris collection chamber 800. Once inside the collection chamber 800, the liquid nitrogen continues to evaporate, and the gas is discharged through the exhaust port, leaving the debris inside. This structure utilizes the pressure created by the natural evaporation of liquid nitrogen to assist in debris removal, eliminating the need to completely drain the liquid nitrogen from the experimental chamber 100 or wait for it to heat up before cleaning.

[0052] Based on the above embodiments, it also includes a linear drive element 900 and a magnetic coupling element 910. The magnetic coupling element 910 is connected to the linear drive element 900 and is driven by the linear drive element 900 to move. A slidable scraper 140 is installed on the inner bottom surface of the experimental chamber 100. The scraper 140 is in contact with the inner bottom surface of the experimental chamber 100. The cleaning port 130 is located at the end of the movement path of the scraper 140. A magnetic force receiving part 141 is provided at one end of the scraper 140 close to the side wall of the experimental chamber 100. The magnetic coupling element 910 is magnetically coupled to the magnetic force receiving part 141 of the scraper 140 through the side wall of the experimental chamber 100.

[0053] In this embodiment, a linear drive element 900 is disposed outside the experimental chamber 100 and can be an electric push rod, a cylinder, or a linear motor. The linear drive element 900 is connected to a magnetic coupling element 910 and is used to drive the magnetic coupling element 910 to move along the outer wall of the experimental chamber 100. Both the magnetic coupling element 910 and the magnetic force-receiving part 141 are magnetic components. When the linear drive element 900 drives the magnetic coupling element 910 to move, the magnetic coupling element 910 drives the magnetic force-receiving part 141 to move synchronously through magnetic force, thereby driving the scraper 140 to slide towards the cleaning port 130. The scraper 140 scrapes and sends the debris that has settled on the bottom surface of the experimental chamber 100 to the cleaning port 130.

[0054] It should be noted that the magnetic coupling element 910 is located outside the experimental chamber 100, while the scraper 140 is located inside the experimental chamber 100, with the two transmitting driving force through the side wall of the experimental chamber 100. The experimental chamber 100 does not require a through-drive shaft for the scraper 140, and the experimental chamber 100 does not need to be opened during the movement of the scraper 140. This structure allows the internal scraper 140 to be driven to clean debris while maintaining the experimental chamber 100 in a closed state.

[0055] Based on the above embodiments, the liquid nitrogen storage chamber 600 includes an outer shell and an inner liner. The inner liner is disposed inside the outer shell, and a vacuum insulation interlayer is formed between the inner liner and the outer shell. The vacuum insulation interlayer is lined with an insulation layer made of alternating layers of aluminized polyester film and glass fiber paper.

[0056] When external heat is transferred to the interior of the liquid nitrogen storage chamber 600, it must pass through the outer shell, vacuum insulation layer, insulation layer, and inner liner. The vacuum insulation layer and insulation layer together slow down the transfer of external heat into the liquid nitrogen storage chamber 600, thereby slowing down the evaporation of liquid nitrogen.

[0057] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment 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 indicator will also change accordingly.

[0058] Furthermore, in this utility model, the use of terms such as "first," "second," and "a" is 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0059] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it 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 utility model according to the specific circumstances.

[0060] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A horizontal coaxial brittle fracture sample preparation device in a liquid nitrogen environment, characterized in that, include: Experimental chamber (100), the experimental chamber (100) being configured to contain liquid nitrogen and samples; A horizontal clamping mechanism, comprising a first clamping head (210) and a second clamping head (220), both the first clamping head (210) and the second clamping head (220) being located within the experimental chamber (100), the clamping openings of the first clamping head (210) and the second clamping head (220) being located on the same horizontal axis, and the first clamping head (210) and the second clamping head (220) being mirror-symmetrically arranged about the vertical plane between them; A horizontal bidirectional tension actuator, comprising a servo motor (300), a linear guide rail (400), and a lead screw (500); The linear guide rail (400) is slidably connected to a first nut block (410) and a second nut block (420), and the sliding trajectory of the first nut block (410) and the sliding trajectory of the second nut block (420) are both parallel to the horizontal axis. The servo motor (300) is motion-coupled with the lead screw (500). The lead screw (500) is provided with a first threaded section (510) and a second threaded section (520) arranged sequentially along its axial direction. The lead of the first threaded section (510) and the second threaded section (520) are equal and opposite in direction. The first threaded section (510) is threadedly connected to the first nut block (410), and the second threaded section (520) is threadedly connected to the second nut block (420). The first nut block (410) is provided with a first connecting rod (411), which passes through the wall of the experimental chamber (100) and is fixedly connected to the first clamping head (210); the second nut block (420) is provided with a second connecting rod (421), which passes through the wall of the experimental chamber (100) and is fixedly connected to the second clamping head (220); The first clamping head (210) and the second clamping head (220) are configured to be driven by the lead screw (500) to move in opposite directions at the same speed along the horizontal axis.

2. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 1, characterized in that, The horizontal bidirectional tension actuator also includes a reducer (310), the output shaft of the servo motor (300) is connected to the input shaft of the reducer (310), and the output shaft of the reducer (310) is connected to the lead screw (500).

3. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 1, characterized in that, The experimental chamber (100) has a first through hole on the side wall corresponding to the first clamping head (210), and the experimental chamber (100) has a second through hole on the side wall corresponding to the second clamping head (220). The first connecting rod (411) passes through the first through hole, and the second connecting rod (421) passes through the second through hole. Sealing rings are provided between the first connecting rod (411) and the first through hole, and between the second connecting rod (421) and the second through hole.

4. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 1, characterized in that, It also includes a liquid nitrogen storage chamber (600) and a liquid nitrogen delivery mechanism. The input end of the liquid nitrogen delivery mechanism is connected to the liquid nitrogen storage chamber (600), and the output end of the liquid nitrogen delivery mechanism is connected to the experimental chamber (100). The liquid nitrogen delivery mechanism is configured to deliver liquid nitrogen from the liquid nitrogen storage chamber (600) to the experimental chamber (100).

5. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 4, characterized in that, The liquid nitrogen delivery mechanism includes a liquid nitrogen replenishment pump, a solenoid valve, and a replenishment pipeline (700). The two ends of the replenishment pipeline (700) are connected to the experimental chamber (100) and the liquid nitrogen storage chamber (600), respectively. The liquid nitrogen replenishment pump and the solenoid valve are both connected in series on the replenishment pipeline (700).

6. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 5, characterized in that, It also includes a controller. The experimental chamber (100) is equipped with a liquid level probe (110). The liquid level probe (110), the liquid nitrogen replenishment pump, the solenoid valve and the servo motor (300) are all electrically connected to the controller.

7. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 6, characterized in that, A weighing sensor is installed at the bottom of the liquid nitrogen storage chamber (600), and the weighing sensor is electrically connected to the controller.

8. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 1, characterized in that, The experimental chamber (100) has an opening for taking out and putting in samples. The experimental chamber (100) is equipped with a cover (120) for controlling the opening and closing of the opening. A chip collection chamber (800) is installed at the bottom of the experimental chamber (100). The chip collection chamber (800) is provided with a waste inlet and an exhaust port. A cleaning port (130) is provided on the bottom wall of the experimental chamber (100). The chip collection chamber (800) is connected to the cleaning port (130) of the experimental chamber (100) through the waste inlet. A valve (810) is provided between the waste inlet and the cleaning port (130).

9. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 8, characterized in that, It also includes a linear drive element (900) and a magnetic coupling element (910). The magnetic coupling element (910) is connected to the linear drive element (900) and is driven by the linear drive element (900) to move. A slidable scraper (140) is installed on the inner bottom surface of the experimental chamber (100). The scraper (140) is in contact with the inner bottom surface of the experimental chamber (100). The cleaning port (130) is located at the end of the movement path of the scraper (140). A magnetic force receiving part (141) is provided at one end of the scraper (140) close to the side wall of the experimental chamber (100). The magnetic coupling element (910) is magnetically coupled to the magnetic force receiving part (141) of the scraper (140) through the side wall of the experimental chamber (100).

10. The liquid nitrogen environment horizontal coaxial brittle fracture sample preparation device as described in claim 4, characterized in that, The liquid nitrogen storage chamber (600) includes an outer shell and an inner liner. The inner liner is disposed inside the outer shell, and a vacuum insulation interlayer is formed between the inner liner and the outer shell. The vacuum insulation interlayer is lined with an insulation layer made of alternating layers of aluminized polyester film and glass fiber paper.

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