A scalable multi-pressure body and separated multi-cavity granular body high-strength intelligent sample pressing device and sample pressing method

Abstract

The present application relates to a kind of extendable multi-pressure body and separate multi-cavity granular body high-strength intelligent sample pressing device and sample pressing method, wherein the sample pressing device includes multi-station rack, at least one set of independent sample pressing demolding unit, intelligent control protection equipment and intelligent sensor.The independent sample pressing demolding unit is composed of upper pressing driving mechanism and longitudinal separate circular ring mold;Upper pressing driving mechanism is installed in rack, and mold can be opened and closed longitudinally and can be detachably arranged in rack.Intelligent control protection equipment is electrically connected with sample pressing demolding unit, and intelligent sensor is arranged at the bottom of mold and transmits signal to control equipment to detect the density of internal granular body.The present application can realize accurate control of sample quality, non-destructive efficient demolding, multi-station parallel operation, while reducing equipment loss and experimental cost, meet the demand of geotechnical engineering comparative experiment.

Description

Technical Field

[0001] This invention relates to the technical field of geotechnical engineering experimental equipment, and more specifically, to a high-strength intelligent compaction device and method for compacting granular materials, which is an expandable multi-compressor and a separate multi-cavity compactor. Background Technology

[0002] In geotechnical engineering experiments, the compaction and demolding of granular materials (such as cohesive soil, sandy soil, and gravelly soil) are crucial steps in ensuring the reliability of data from subsequent strength and compression tests. Currently, laboratories commonly use compaction equipment consisting of a molding cylinder and a compaction platform, and related technologies are documented in published patents.

[0003] Chinese invention patent CN104374625B (Invention title: A Semi-automatic Multifunctional Geotechnical Testing Sample Compaction Device) discloses a sample compaction device integrating a support system, a power and control system, a molding system, and a sample compaction system. Through the coordinated control of a movable sample compaction platform and a hydraulic system, it achieves layered compaction molding of hollow or solid cylindrical samples. Furthermore, it can be adapted to different testing needs by changing the molding and sample compaction components, thus optimizing the diversity of sample molding and the semi-automatic operation. However, this patented technology and similar traditional sample compaction devices still have inherent technical defects in mold structure design, process flow adaptation, and quality monitoring mechanisms, specifically as follows:

[0004] 1. The demolding structure design leads to a complex operating procedure and makes samples easily damaged. Existing technologies mostly employ an integrated molding cylinder (or ring mold) structure. After molding, the sample forms a tight fit with the inner wall and bottom of the molding cylinder, resulting in significant static friction at the interface (the static friction at the interface of sandy soil samples can reach 15-20N). To complete demolding, multiple steps are required: First, a rigid tool is used to apply impact force along the bottom edge of the molding cylinder to initially separate the bottom support structure from the molding cylinder; second, the original bottom support is disassembled and replaced with a ring-shaped transition base, ensuring that the concentricity deviation between the base and the molding cylinder is ≤0.5mm; finally, the molding cylinder with the ring base is placed back into the sample pressing system, and the sample is ejected a second time by hydraulically driven pressure hammer. This process requires 5-6 manual interventions, and demolding a single sample takes 40-50 minutes. Simultaneously, the impact force easily causes micro-cracks inside the sample (the crack incidence rate in brittle soil samples is not less than 30%), and the concentricity deviation causes local compression deformation of the sample, ultimately leading to a molding density deviation of not less than 1.5%, affecting the accuracy of experimental data.

[0005] 2. The sequential execution of the sample pressing and demolding processes limits overall efficiency. Existing compaction techniques require layered compaction and constant pressure to maintain the desired shape. To achieve the preset density standard (e.g., saturated cohesive soil forming density ≥ 1.8 g / cm³), a constant pressure of 15-50 kN must be maintained for 1-1.5 hours. Adding the time spent on molding (manual layered filling and leveling, taking 8-12 minutes per cycle) and demolding, the entire process for a single sample, from molding to demolding, takes 1.5-2.5 hours. Because these devices use a single-station serial operation mode, demolding or molding the next set of samples cannot be performed simultaneously during compaction, creating a bottleneck in the process. When conducting multiple comparative experiments in the laboratory (e.g., different combinations of moisture content and compaction parameters), a single device can only complete a maximum of 3-4 sets of sample preparations per day, which is insufficient to meet the demands of high-frequency experiments.

[0006] 3. Lack of real-time quality monitoring mechanisms leads to poor sample consistency. The existing power and control system only achieves basic control of the lifting and lowering displacement and hydraulic pressure of the compaction platform, without setting up a module for real-time monitoring and feedback of core parameters of the compaction process. Sample quality judgment relies on two methods: one is the layered compaction process controlled by the operator according to the test specifications, and the other is a preset fixed constant pressure time. This design has three technical limitations: First, there is no unified and objective standard for judging compaction, resulting in poor consistency of sample quality between different batches or prepared by different operators, which cannot meet the basic requirement of sample homogeneity for comparative experiments; Second, the fixed holding time cannot be adapted to the compaction characteristics of granular materials with different particle sizes and moisture contents, which easily leads to the phenomenon of "surface compaction and internal voids", rendering subsequent experimental data invalid; Third, core indicators such as sample volume change and density increment during the compaction process lack real-time feedback, and abnormal working conditions (such as deformation of the mold cylinder and uneven layered filling) cannot be identified in time. Sample qualification can only be judged after demolding, resulting in waste of resources. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies in granular sample preparation, such as complex operation procedures, high sample breakage rate, low preparation efficiency, and poor quality consistency. It provides a high-strength intelligent granular sample pressing device with expandable multi-compressor and separable multi-cavity design. This device can achieve precise and controllable sample quality, non-destructive and efficient demolding, and multi-station parallel operation, while reducing equipment wear and experimental costs, thus meeting the core requirements of comparative experiments in geotechnical engineering.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A high-strength intelligent sample pressing device for granules with expandable multi-compressor and separable multi-cavity components is provided. It includes a multi-station frame, at least one set of independent sample pressing and demolding units, intelligent control and protection equipment, and intelligent sensors. Each independent sample pressing and demolding unit includes an upper pressure drive mechanism and a longitudinally separable annular mold. The upper pressure drive mechanism is mounted on the multi-station frame. The longitudinally separable annular mold opens and closes along the longitudinal direction and is detachably mounted within the multi-station frame. The intelligent control and protection equipment is electrically connected to the independent sample pressing and demolding units. The intelligent sensor is located at the bottom of the longitudinally separable annular mold and transmits signals to the intelligent control and protection equipment to detect the density of granules within the longitudinally separable annular mold.

[0009] This invention discloses a scalable multi-compressor and separable multi-cavity high-strength intelligent granular sample pressing device. Its working principle is as follows: Structural coordination logic: The multi-station frame serves as a rigid support foundation. Precisely positioned fixing holes and mounting slots ensure the coaxiality of the upper pressure drive mechanism, the longitudinally separable annular mold, and the intelligent sensor, providing structural assurance for sample pressing stability. The independent sample pressing and demolding unit adopts a detachable design, allowing for flexible addition or reduction of the number of units according to experimental needs. Furthermore, a single unit failure does not affect the overall operation, improving the equipment's fault tolerance. The longitudinally separable annular mold, by opening along the longitudinal direction, avoids the minor misalignment and powder leakage problems that may occur during demolding due to uneven force distribution in traditional integrated molds. Power and monitoring coordination logic: Upper pressure drive... The servo electric cylinder of the actuator serves as the power source, forming a closed-loop control with the built-in pressure sensor. It can output a preset pressure. The intelligent sensor is installed at the bottom of the mold to collect sample density and sample data in real time and transmit it to the intelligent control and protection equipment. The intelligent control and protection equipment analyzes the data through an independent sample pressing and demolding unit, dynamically adjusts the operating status of the servo electric cylinder, ensures that the sample pressing process meets the preset parameters, and provides real-time feedback on the equipment operating status and sample data. The intelligent control and protection equipment supports independent parameter setting for each independent sample pressing and demolding unit and supports asynchronous cyclic parallel operation of the "mold loading, sample pressing, and demolding" process, realizing an intelligent closed loop of "precise pressure control - real-time data monitoring - dynamic status adjustment - asynchronous cyclic parallel operation".

[0010] The core technical principle of this invention lies in breaking through the technical limitations of traditional equipment through modular and intelligent structural design: multi-station racks enable asynchronous parallel operation, solving process bottlenecks; a longitudinally separated ring mold design achieves non-destructive demolding; intelligent sensors and linkage control technology establish a real-time quality monitoring mechanism to ensure sample consistency; and multiple safety protection modules are integrated to improve operational safety and equipment stability. This technical solution, through the coordinated work of various components, achieves high efficiency, precision, and intelligence in the preparation of granular samples, effectively solving many pain points of existing technologies.

[0011] Furthermore, the multi-station frame has a layered structure. The upper layer of the multi-station frame is provided with multiple fixing holes, and the lower layer of the multi-station frame is provided with mounting grooves corresponding to the positions of the fixing holes. The upper pressure drive mechanism is connected to the fixing holes, the smart sensor is installed in the mounting groove, and the upper end face of the smart sensor is installed on the bottom of the longitudinally separated annular mold.

[0012] In this technical solution, the layered structure design and precise correspondence between holes and slots ensure the coaxiality and positioning accuracy of the pressing drive mechanism, the longitudinally separated annular mold, and the intelligent sensor, providing a structural foundation for the stability of the pressing process and the consistency of sample quality. The design of multiple fixed holes and mounting slots ensures the expandability of the equipment, allowing for flexible addition or reduction of the number of independent pressing and demolding units according to experimental needs.

[0013] Furthermore, the longitudinally separated ring mold includes a first module, a second module, and a locking mechanism. The first module and the second module are two symmetrical semi-circular arc modules. The first module has a boss at the connection with the second module, and the second module has a sealing groove that matches the boss. The boss is inserted into the sealing groove. Multiple locking mechanisms are arranged along the height direction of the longitudinally separated ring mold, and the locking mechanisms are respectively connected to the first module and the second module.

[0014] This technical solution employs a symmetrical semi-circular arc module design, combined with an interlocking structure of bosses and sealing grooves, to ensure the sealing performance and structural stability of the mold after closing. Multiple locking mechanisms positioned along the height direction provide uniform and reliable locking force, preventing mold separation during sample pressing and ensuring effective transmission of pressing pressure. Simultaneously, the longitudinally separable structure allows for direct mold disassembly for demolding without external impact or secondary pressurization, solving the sample breakage problem caused by traditional demolding methods.

[0015] Furthermore, the locking mechanism includes a locking buckle, a snap-fit ​​groove, and a locking status sensor. The locking buckle is fixedly installed on the first module along the height direction, and the snap-fit ​​groove is located on the second module relative to the locking buckle. The locking buckle and the snap-fit ​​groove cooperate to lock the longitudinally separated annular mold. The locking status sensor is located on the locking buckle or the snap-fit ​​groove to detect the coupling state or locking force between the two and generate a locking signal to be transmitted to the intelligent control and protection device.

[0016] In this technical solution, the precise cooperation between the locking buckle and the snap-fit ​​groove ensures the reliability of mold locking, while the setting of the locking status sensor enables real-time monitoring of the locking status, providing feedback signals for intelligent control, avoiding sample pressing failure or equipment failure due to incomplete mold locking, and improving the intelligence level and operational safety of the equipment.

[0017] Furthermore, the upper pressure drive mechanism includes a body, a servo electric cylinder, an upper pressure head, and a pressure sensor. The body is connected to the fixed hole, the pressure sensor is built into the servo electric cylinder, the upper pressure head is connected to the output end of the servo electric cylinder, and the servo electric cylinder and the pressure sensor are electrically connected to the intelligent control and protection device.

[0018] In this technical solution, a servo electric cylinder is used as the power source, coupled with a built-in pressure sensor, to achieve precise control and real-time feedback of the sample pressing pressure. The connection structure design between the upper pressure head and the output end of the servo electric cylinder facilitates the replacement of the upper pressure head according to different experimental needs, improving the adaptability of the equipment. The servo electric cylinder features high positioning accuracy and stable thrust, ensuring the uniformity and stability of the sample pressing process and providing power assurance for sample quality.

[0019] Furthermore, the upper surface of the smart sensor and the inner circumference of the longitudinally separated annular mold are both coated with polytetrafluoroethylene.

[0020] In this technical solution, the polytetrafluoroethylene coating has a low coefficient of friction. By applying this coating to the upper surface of the smart sensor and the inner circumference of the mold, the static friction between the sample and the contact surface can be reduced. On the one hand, this facilitates demolding and further reduces the risk of sample breakage; on the other hand, it can prevent the sample from sticking to the contact surface, ensuring sample integrity and a clean experimental environment, while also reducing equipment wear and extending its service life.

[0021] Furthermore, the intelligent control and protection equipment includes an intelligent control platform, a linkage control group, and a safety protection group. The linkage control group is electrically connected to the intelligent control platform and the servo electric cylinder, and the safety protection group is integrated into the multi-station rack and the linkage control group.

[0022] In this technical solution, the integrated design of an intelligent control platform, a linkage control group, and a safety protection group enables intelligent control and comprehensive safety protection of the equipment. The linkage control group can precisely adjust the operating status of the servo electric cylinder based on feedback signals from intelligent sensors and pressure sensors to ensure that the sample pressing process meets preset parameters; the safety protection group can monitor the equipment's operating status in real time, respond promptly to various abnormal operating conditions, and ensure the safety of operators and equipment.

[0023] Furthermore, the intelligent control platform is also equipped with a touch operation panel, an emergency braking button, and a pressure overload alarm light. The touch operation panel is located on the front inclined surface of the intelligent control platform, and the pressure overload alarm light and the emergency braking button are arranged sequentially above the touch operation panel along the height direction.

[0024] In this technical solution, the human-machine interface design is optimized. The touch operation panel set on the front sloping surface is convenient for operators to observe and operate, and can realize functions such as parameter setting and operation status monitoring. The reasonable layout of the emergency brake button and pressure overload alarm light improves the safety and ease of use of the equipment. When abnormal conditions such as pressure overload occur, the alarm light will sound in time, and the operator can quickly press the emergency brake button to stop the equipment operation, minimizing the risk.

[0025] The present invention also provides a sample pressing method for a high-strength intelligent sample pressing device for granular materials with expandable multi-compressor and separable multi-cavity components, wherein S1, granular materials are filled into a longitudinally separable circular mold and the mold is locked, and the linkage control group initializes the sample pressing pressure and pressure holding parameters of the corresponding station. S2. Output instructions to the intelligent control platform to apply a preset pressing pressure to the granular material by driving the upper pressing head through the servo electric cylinder, and collect sample density data in real time by the intelligent sensor set at the bottom of the longitudinally separated circular mold during the pressing process. S3, the linkage control group, and the intelligent sensors input the collected density data into the intelligent control platform for processing, and calculate the rate of change of sample density over time. S4. When the density change rate is continuously lower than the first threshold for a preset time, the linkage control group automatically determines that the sample has reached a stable molding state, and the intelligent control platform issues an instruction to control the servo electric cylinder through the linkage control group to end the pressure holding process. S5. After the stable molding state is determined, the linkage control group generates a demolding permission signal, which allows the locking mechanism of the longitudinally separated ring mold to unlock and perform separation demolding, thereby realizing the non-destructive removal of the granular sample.

[0026] This invention discloses a high-strength intelligent compaction device for granular materials with expandable multi-compressor and separable multi-cavity components. The process logic is as follows: Step S1: Mold locking and parameter initialization lay the foundation for the compaction process. Locking ensures mold sealing and rigidity, while parameter settings adapt to different granular material characteristics. Step S2: A servo electric cylinder precisely applies a preset pressure, while a smart sensor collects density data at high frequency, achieving simultaneous "pressurization-monitoring" to avoid the blindness of traditional compaction. Step S3: The sample forming state is quantified into objective data by calculating the rate of change of density over time, replacing the traditional method of relying on experience or fixed holding time. Step S4: A continuous density change rate below a threshold is used as the forming judgment criterion to ensure the sample reaches a stable and dense state, avoiding the false density phenomenon of "surface compaction, internal voids." Step S5: After forming judgment, a demolding permission signal is generated. Combined with the longitudinal opening and closing design of the longitudinally separable mold, the sample is removed without damage, completing the closed-loop process of "mold loading-compaction-monitoring-judgment-demolding." Intelligent adaptation logic: In the methodology, the intelligent control and protection equipment serves as the core hub, coordinating the parameter settings, data acquisition, and status switching of each workstation. It can support independent parameter configuration and asynchronous operation of multiple workstations, meaning that different workstations can simultaneously execute different processes such as mold assembly, sample pressing, and demolding, eliminating process waiting time and improving experimental efficiency.

[0027] The technical advantages of this method are as follows: By quantitatively determining the rate of change in density, the consistency of samples is significantly improved, with density deviations of samples prepared by different batches and different operators ≤0.3%; the multi-station asynchronous operation mode shortens the single sample preparation cycle from 1.5-2.5 hours to less than 1 hour, increasing the daily preparation volume by more than 200%; the non-destructive demolding process ensures a sample integrity rate of ≥95%, effectively guaranteeing the reliability of subsequent experimental data; the fully intelligent operation reduces human intervention, minimizes resource waste, and is suitable for high-frequency, multi-specification geotechnical engineering experiments.

[0028] Further, in step S4, the first threshold is the absolute value threshold of the density change rate. When the density change of the sample per unit time is less than this threshold, the sample is determined to have entered the density stabilization stage. In step S5, before generating the demolding permission signal, the linkage control module is used to detect the locking state of the longitudinally separated ring mold. Only when the mold locking mechanism is detected to be in a fully locked state is the pressing termination judgment step and the demolding permission step allowed to be executed. In step S2, when the device includes multiple sets of independent pressing and demolding units, the linkage control group executes the pressing termination judgment step and the demolding permission step respectively according to the station status of each independent pressing and demolding unit, so that different stations operate asynchronously and do not interfere with each other during the mold loading, pressing, and demolding stages.

[0029] This further improved pressing method provides an objective and unified standard for judging sample forming by clarifying the absolute value threshold of the density change rate, ensuring the consistency of samples from different batches; the locking state detection step further enhances operational safety and avoids pressing abnormalities caused by mold not locking; the multi-station asynchronous operation design fully leverages the advantages of the multi-station frame to achieve asynchronous parallel processing of mold loading, pressing, and demolding processes, improving preparation efficiency.

[0030] Compared with the prior art, the beneficial effects of the present invention are: 1. Significantly improved sample quality and good consistency: This invention adopts a longitudinally separated ring mold design, combined with a boss-sealing groove positioning structure and a polytetrafluoroethylene friction-reducing coating, completely eliminating the external force impact and secondary pressurization operation of traditional demolding methods. The sample breakage rate is reduced from more than 30% in the prior art to less than 5%, and the integrity rate is ≥95%. The servo electric cylinder of the upper pressure drive mechanism and the built-in pressure sensor realize closed-loop pressure control, with high pressure holding accuracy. Combined with the real-time monitoring and feedback of density by intelligent sensors, the sample molding density deviation is reduced from ≥1.5% in the prior art to ≤0.3%, effectively meeting the strict requirements of comparative experiments for sample uniformity. 2. Significantly improved preparation efficiency, adaptable to high-frequency requirements: The modular design of the multi-station rack and independent sample pressing and demolding units enables parallel operation at multiple stations. Different stations can perform mold loading, sample pressing, and demolding operations asynchronously, completely breaking through the process bottleneck of traditional single-station serial operation. The entire process time for a single sample from mold loading to demolding is reduced from 1.5-2.5 hours in the existing technology to less than 1 hour. The daily preparation capacity of a single machine is increased from 3-4 sets to 12-18 sets, with an efficiency improvement of more than 200%, which can fully meet the high-frequency, large-volume experimental needs of the laboratory. 3. High scalability and adaptability, low maintenance cost: The multi-station frame with multiple fixing holes and mounting slots supports the flexible addition or removal of independent pressing and demolding units. The number of stations can be adjusted according to the experimental scale. The failure of a single unit does not affect the operation of other units, demonstrating strong fault tolerance. The detachable structure of the longitudinally separated ring mold and the upper pressing head facilitates the replacement of parts of different sizes, adapting to the needs of preparing granular samples of different particle sizes and specifications. The PTFE coating and modular design reduce equipment wear and extend service life. The monthly deformation rate of the base is reduced from 20% in the existing technology to below 5%, significantly reducing maintenance frequency and cost.

[0031] 4. High level of intelligence and strong data reliability: This invention uses intelligent sensors to collect sample density data in real time and links the control group to dynamically adjust the pressing parameters. The density change rate is used as the molding judgment standard, replacing the traditional fixed pressing time mode. This effectively avoids the phenomenon of "surface compaction and internal voids" and ensures the validity of experimental data. All pressing parameters and process data can be recorded and traced through the intelligent control platform, providing complete data support for experimental analysis and further improving the reliability of experimental results. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of a high-strength intelligent granular sample pressing device with expandable multi-compressor and separable multi-cavity components according to the present invention. Figure 2 This is a schematic diagram of the assembly structure of the multi-station frame and the independent sample pressing and demolding unit of the present invention; Figure 3 This is an assembly side view of the multi-station frame and independent sample pressing and demolding unit of the present invention; Figure 4 This is a top view of the connection structure between the first module and the second module of the present invention; Figure 5 This is a schematic diagram of the open state structure of the longitudinally separable ring mold of the present invention; Figure 6 This is a schematic diagram of the intelligent sensor of the present invention; Figure 7 This is a schematic diagram of the closed state structure of the longitudinally separated ring mold of the present invention.

[0033] In the attached diagram: 1. Multi-station frame; 11. Fixing hole; 12. Mounting slot; 2. Independent pressing and demolding unit; 21. Upper pressure drive mechanism; 211. Body; 212. Servo electric cylinder; 213. Upper pressure head; 214. Pressure sensor; 22. Longitudinal split ring mold; 221. First module; 222. Second module; 223. Locking mechanism; 2231. Locking buckle; 2232. Snap-fit ​​groove; 224. Boss; 225. Sealing groove; 3. Intelligent control and protection equipment; 31. Intelligent control platform; 311. Touch operation panel; 312. Emergency brake button; 313. Pressure overload alarm light; 32. Linkage control group; 33. Safety protection group; 4. Intelligent sensor. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0035] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0036] Example 1 like Figures 1 to 7 The illustration shows a first embodiment of the scalable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granules according to the present invention. It includes a multi-station frame 1, at least one set of independent sample pressing and demolding units 2, an intelligent control and protection device 3, and an intelligent sensor 4. Each set of independent sample pressing and demolding units 2 includes an upper pressure drive mechanism 21 and a longitudinally separable annular mold 22. The upper pressure drive mechanism 21 is installed on the multi-station frame 1. The longitudinally separable annular mold 22 opens and closes in the longitudinal direction and is detachably installed in the multi-station frame 1. The intelligent control and protection device 3 is electrically connected to the independent sample pressing and demolding units 2. The intelligent sensor 4 is located at the bottom of the longitudinally separable annular mold 22 and transmits signals to the intelligent control and protection device 3 to detect the density of granules in the longitudinally separable annular mold 22.

[0037] Multi-station frame 1: It adopts a layered Q235 steel welded structure, and the surface is sprayed with epoxy anti-rust paint. The upper layer has 4 fixing holes 11 with a spacing of 200mm, and the positioning accuracy is ±0.1mm. The lower layer has 4 corresponding base mounting slots 12, and the coaxiality deviation with the fixing holes 11 is ≤0.1mm. The inner wall of the mounting slots 12 is reserved with positioning pin holes to ensure precise docking of the upper and lower parts.

[0038] The longitudinally separated circular mold 22 consists of two symmetrically designed semi-circular modules, a first module 221 and a second module 222, made of 304 stainless steel with a wall thickness of 6mm, an inner diameter of 80mm, and a height of 120mm. The first module 221 has a boss 224 (2mm high x 5mm wide) at its connection point, and the second module 222 has a corresponding sealing groove 225. The clearance between the boss 224 and the sealing groove 225 is 0.08mm. A nitrile rubber sealing ring (3mm wide x 2mm deep) is embedded in the sealing groove 225. Three sets of 304 stainless steel quick-locking mechanisms 223 are symmetrically fixed to the outer wall of the mold, with a locking force ≥5kN. The inner wall and mating surfaces of the mold are coated with a 0.2mm thick polytetrafluoroethylene coating to reduce the coefficient of friction.

[0039] The upper pressure drive mechanism 21 includes a body 211, a servo electric cylinder 212, an upper pressure head 213, and a built-in pressure sensor 214. The servo electric cylinder 212 is a TOLOMATICES16 model with a rated thrust of 50kN and a positioning accuracy of ±0.05mm. It is fixed to the frame fixing hole 11 by bolts. The upper pressure head 213 is made of 304 stainless steel with a mirror-polished bottom and is detachably connected to the output end of the servo electric cylinder 212. The pressure sensor 214 has a pressure adjustment range of 10-50kN, a pressure holding accuracy of ±0.5kN, and is electrically connected to the intelligent control and protection device 3.

[0040] Intelligent Sensor 4: This sensor is a density monitoring sensor installed in the mounting slot 12 of the base. Its diameter matches the inner diameter of the longitudinally separated circular mold 22, and its thickness is 18mm. It is made of 304 stainless steel. The upper surface of the sensor is coated with a 0.2mm thick polytetrafluoroethylene coating, which fits tightly against the lower surface of the mold. It collects sample density and sample formation data in real time and transmits them to the control equipment.

[0041] 1. Selection and Installation Design of Smart Sensor 4: The smart monitoring sensor built into the base adopts a high-frequency electromagnetic induction density sensor (suitable for non-contact monitoring of granular materials). The main body of the smart sensor 4 is embedded in the pre-reserved sealed mounting hole in the base (the hole is located 5-8mm below the upper surface of the base and is coaxial with the base). The sensor sensing surface is parallel to the upper surface of the base and the distance is ≤2mm. The inner wall of the mounting hole is sealed with a nitrile rubber sealing ring to prevent soil particles or moisture from entering, while not affecting the flatness of the upper surface of the base (ensuring the fitting accuracy with the mold).

[0042] 2. Core principle of density monitoring: The intelligent sensor 4 emits high-frequency electromagnetic waves of a fixed frequency (100-200MHz), which penetrate the polytetrafluoroethylene coating on the upper surface of the base and act on the soil sample during the compaction process. Changes in soil density will cause regular changes in its dielectric constant and electromagnetic impedance. The sensor receives the reflected electromagnetic signal and converts physical parameters such as signal strength and phase shift into electrical signals, realizing a one-to-one correspondence between density and electromagnetic parameters.

[0043] 3. Data Processing and Calibration Mechanism: The raw electrical signals collected by the intelligent sensor 4 are transmitted to the PLC controller (Siemens S7-1200) in the linkage control group 32 through shielded wires. The control software has a built-in calibration algorithm model (established based on previous experimental data, covering the density-electromagnetic parameter correspondence of soils with different moisture contents and particle size distributions). The real-time signal is fitted and calculated using the least squares method, and the real-time soil density value (unit: g / cm³) is directly output. At the same time, it supports pre-experiment calibration (inputting standard density soil samples for parameter correction) to ensure the monitoring accuracy of different soil types.

[0044] 4. Real-time feedback and linkage control: Density data is sampled at a frequency of 1 time / second and displayed in real time on the intelligent control platform 31, while being synchronized to the sample compression control logic; when the density change rate is detected to be below the first threshold (e.g., 0.01 g / cm³) for a continuous preset time (which can be set via software, such as 3-5 minutes), the system will respond. When the sample reaches a stable molding state (min), the PLC automatically determines that the sample has reached a stable molding state and triggers the pressure holding termination command; if the density data is abnormal (such as exceeding the preset reasonable range), the safety protection module will be activated, the red fault light will be lit and the message "Density monitoring abnormal" will be displayed.

[0045] 5. Accuracy Guarantee Design: The intelligent sensor 4 itself has a measurement accuracy of ≤ ±0.02g / cm³. Combined with the positioning accuracy of the base (±0.1mm) and the pressure closed-loop control (pressure holding accuracy ±0.5kN), the final soil density deviation is ≤0.3%, which fully meets the requirements of geotechnical engineering comparative experiments for sample uniformity.

[0046] The working principle of this embodiment is as follows: Assembly steps: First, fix the smart sensor 4 to the base mounting slot 12 with positioning pins, ensuring that the horizontal deviation of the upper end face is ≤0.05mm; then, connect the two semi-circular arc modules of the longitudinally separated ring mold 22 through the boss-groove structure, and lock them together with a quick snap fastener, and place them on the upper end face of the smart sensor 4, ensuring that the coaxiality deviation between the mold axis and the center of the sensor is ≤0.2mm; finally, fix the upper pressure drive mechanism 21 to the frame fixing hole 11 with bolts, and adjust the angle so that the coaxiality deviation between the upper pressure head 213 and the mold is ≤0.1mm.

[0047] Compaction operation: Fill the mold with a preset mass of cohesive soil sample with a moisture content of 20% and a target density of 1.9 g / cm³. Set the compaction pressure to 25 kN and the holding time to 40 minutes through the intelligent control and protection device 3. The servo electric cylinder 212 drives the upper pressure head 213 to press down at a uniform speed of 4 mm / s. The pressure sensor 214 provides real-time feedback of pressure data to ensure the accuracy of the holding time. During the compaction process, the intelligent sensor 4 collects the density data every 10 seconds and transmits it synchronously to the control device for display.

[0048] Demolding operation: After the pressure holding is completed, unlock the quick buckle and split the two semi-circular arc modules horizontally to both sides. The soil sample is naturally retained on the upper surface of the sensor under the friction reduction effect of the polytetrafluoroethylene coating. It can be directly taken out. The demolding time is low, the sample integrity rate is ≥95%, and the molding density deviation is small.

[0049] The effect of this embodiment: This embodiment achieves the core logic of "precise pressure control - real-time monitoring - non-destructive demolding": the multi-station frame provides a stable installation foundation, the longitudinally separated mold solves the demolding problem of traditional integrated molds, and the polytetrafluoroethylene coating reduces interface friction; the servo electric cylinder of the pressure drive mechanism and the pressure sensor form a closed-loop control to ensure accurate and stable pressure; the intelligent sensor collects density data in real time, providing an objective basis for judging sample quality, effectively solving the problems of high sample breakage rate and poor consistency in the prior art.

[0050] Example 2 like Figures 1 to 3 As shown, this embodiment is a second embodiment of a scalable multi-compressor and separable multi-cavity high-strength intelligent granular sample pressing device. This embodiment is similar to the first embodiment, except that... Optimization of PTFE coating: A 0.3mm thick PTFE coating was applied to the upper surface of the smart sensor 4 and the inner circumference of the longitudinally separated circular mold 22. The friction coefficient was reduced to ≤0.04 after testing, further reducing the adhesion between the sample and the contact surface. No auxiliary tools were required during the demolding process, and the sample integrity was improved to over 98%.

[0051] Intelligent control and protection equipment 3 includes an intelligent control platform 31, a linkage control group 32, and a safety protection group 33. The linkage control group 32 adopts a Siemens S7-1200 PLC controller, which is electrically connected to the servo electric cylinder 212 and pressure sensor 214 via Ethernet, and is also connected to the intelligent sensor 4 and the locking status sensor signal, supporting independent setting of multi-station parameters and synchronous data processing; the safety protection group is integrated into the frame and the linkage control group, including overload protection, locking detection protection, and emergency stop protection units.

[0052] 2. The working principle of this embodiment is as follows: Parameter settings and status monitoring: The touch operation panel 311 allows independent setting of the sample pressing pressure (10-50kN adjustable) and the holding time (0-180 minutes adjustable) for each station. It displays the current pressure, density, operating status (molding / sample pressing / demolding) and fault prompts in real time. The data storage capacity is ≥1000 sets, and it supports exporting data to Excel format via USB.

[0053] Security protection mechanism implementation: 1. Locking detection and protection: The locking status sensor detects the locking status of the quick-lock buckle in real time. If it is not fully locked, the linkage control group 32 prohibits the start of the sample pressing action, and at the same time, the pressure overload alarm light 313 flashes to alarm, and the touch operation panel 311 displays the fault code "locking not in place".

[0054] 2. Overload protection: When the pressure sensor 214 detects that the pressure of the sample exceeds the preset threshold of 50kN, the safety protection group 33 immediately cuts off the power supply of the corresponding station servo electric cylinder 212, the upper pressure head 213 stops moving, the alarm light continues to flash, and the touch operation panel 311 displays the "pressure overload" fault code.

[0055] 3. Emergency stop protection: If any abnormality occurs during the experiment, press the emergency stop button 312, and all station drive mechanisms will be immediately de-energized to ensure the safety of personnel and equipment. The button must be reset after the fault is cleared before restarting.

[0056] Example 3 like Figure 1 As shown, this embodiment is an example of a sample pressing method for a scalable multi-compressor and separable multi-cavity high-strength intelligent granular sample pressing device. S1: Mold Installation and Parameter Setting: Fill the sandy soil sample with a moisture content of 15% into the four sets of longitudinally separated circular molds 22, lightly press and scrape it flat, then lock the quick-locking buckles. The locking status sensor provides feedback on the locking signal. Set the parameters for each independent pressing and demolding unit 2 through the touch operation panel 311: pressing pressure of station 1 30kN, pressing pressure of station 2 25kN, pressing pressure of station 3 35kN, pressing pressure of station 4 28kN, and the preset threshold for holding pressure time is 60 minutes. The linkage control group 32 completes the parameter initialization.

[0057] S2: Pressurization and Data Acquisition: Output a start command to the intelligent control platform 31. After the linkage control group 32 verifies the validity of the locking signals of all workstations, it controls the servo electric cylinders 212 of each workstation to drive the upper pressure head 213 to apply a preset pressure to the granular material. During the pressing process, the intelligent sensor 4 collects the sample density data of each workstation in real time, and the pressure sensor 214 synchronously feeds back the pressure data. All data are transmitted to the intelligent control platform 31 in real time.

[0058] S3: Data processing and rate of change calculation: The linkage control group 32 processes the collected density data in real time and calculates the rate of change of density within 1 minute, that is, the absolute value of the difference between the density of the current minute and the previous minute.

[0059] S4: Molding judgment and end of holding pressure: Set the first threshold to 0.004 g / (cm³) When the density change rate of a certain station is lower than the threshold for 5 consecutive minutes, the linkage control group 32 automatically determines that the sample has reached a stable molding state, sends a signal to the intelligent control platform, controls the corresponding station servo electric cylinder 212 to end the pressure holding, and the upper pressure head 213 resets upward at a speed of 3mm / s.

[0060] S5: Demolding Permission and Non-destructive Removal: After the stable molding determination is completed, the linkage control group 32 generates a demolding permission signal, and the touch operation panel 311 displays the "Demolding is possible" prompt; the experimenter unlocks the corresponding station mold locking mechanism to perform separation demolding and achieve non-destructive removal of the sample.

[0061] Density change rate threshold determination: The first threshold is set as the absolute value threshold of the density change rate. Through a large number of experiments, this threshold can be adapted to granules with different particle size distributions and moisture contents, effectively avoiding the false density phenomenon of "compact surface and hollow interior", and ensuring uniform sample molding quality.

[0062] Secondary detection of locking status: Before generating the demolding permission signal, the linkage control group checks the mold locking status again. Only when it is confirmed that the locking mechanism is in a fully locked state will the pressing termination judgment and demolding permission steps be executed to avoid sample deformation caused by loosening of the locking midway.

[0063] Multi-station asynchronous operation: The linkage control group 32 executes judgment and permission steps according to the operation status of each station, namely mold loading / sample pressing / demolding, to realize multi-station asynchronous operation: when station 1 performs sample pressing, station 2 can demold simultaneously, station 3 performs mold loading, and station 4 switches to demolding state after completing sample pressing. At the same time, station 1 finishes sample pressing and switches to mold loading state, forming a parallel cycle of "mold loading-sample pressing-demolding" with no process waiting time.

[0064] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0065] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A high-strength intelligent sample pressing device for granular materials with expandable multi-compressor and separable multi-cavity components, characterized in that: The system includes a multi-station frame (1), at least one set of independent sample pressing and demolding units (2), an intelligent control and protection device (3), and an intelligent sensor (4). Each set of independent sample pressing and demolding units (2) includes an upper pressure drive mechanism (21) and a longitudinally separated ring mold (22). The upper pressure drive mechanism (21) is installed on the multi-station frame (1). The longitudinally separated ring mold (22) opens and closes in the longitudinal direction and is detachably installed in the multi-station frame (1). The intelligent control and protection device (3) is electrically connected to the independent sample pressing and demolding unit (2). The intelligent sensor (4) is located at the bottom of the longitudinally separated ring mold (22) and transmits signals to the intelligent control and protection device (3) to detect the particle density inside the longitudinally separated ring mold (22).

2. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 1, characterized in that: The multi-station frame (1) has a layered structure. The upper layer of the multi-station frame (1) is provided with multiple fixing holes (11), and the lower layer of the multi-station frame (1) is provided with mounting grooves (12) corresponding to the positions of the fixing holes (11). The upper pressure drive mechanism (21) is connected to the fixing holes (11), and the smart sensor (4) is installed in the mounting groove (12). The upper end face of the smart sensor (4) is installed on the bottom of the longitudinally separated ring mold (22).

3. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 2, characterized in that: The longitudinally separated ring mold (22) includes a first module (221), a second module (222), and a locking mechanism (223). The first module (221) and the second module (222) are two symmetrical semi-circular arc modules. The first module (221) has a boss (224) at the connection with the second module (222). The second module (222) has a sealing groove (225) that matches the boss (224). The boss (224) is inserted into the sealing groove (225). Multiple locking mechanisms (223) are arranged along the height direction of the longitudinally separated ring mold (22). The locking mechanisms (223) are respectively connected to the first module (221) and the second module (222).

4. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 3, characterized in that: The locking mechanism (223) includes a locking buckle (2231), a snap-fit ​​groove (2232), and a locking status sensor. The locking buckle (2231) is fixedly installed on the first module (221) along the height direction. The snap-fit ​​groove (2232) is located on the second module (222) relative to the locking buckle (2231). The locking buckle (2231) and the snap-fit ​​groove (2232) cooperate to lock the longitudinally separated ring mold (22). The locking status sensor is located on the locking buckle (2231) or the snap-fit ​​groove (2232) to detect the coupling state or locking force of the two and generate a locking signal to be transmitted to the intelligent control protection device (3).

5. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 4, characterized in that: The upper pressure drive mechanism (21) includes a body (211), a servo electric cylinder (212), an upper pressure head (213), and a pressure sensor (214). The body (211) is connected to the fixed hole (11), the pressure sensor (214) is built into the servo electric cylinder (212), the upper pressure head (213) is connected to the output end of the servo electric cylinder (212), and the servo electric cylinder (212) and the pressure sensor (214) are electrically connected to the intelligent control protection device (3).

6. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 1, characterized in that: The upper surface of the smart sensor (4) and the inner circumference of the longitudinally separated circular mold (22) are both coated with polytetrafluoroethylene.

7. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 5, characterized in that: The intelligent control protection device (3) includes an intelligent control platform (31), a linkage control group (32) and a safety protection group (33). The linkage control group (32) is electrically connected to the intelligent control platform (31) and the servo electric cylinder (212). The safety protection group (33) is integrated into the multi-station rack (1) and the linkage control group (32).

8. The expandable multi-compressor and separable multi-cavity high-strength intelligent sample pressing device for granular materials according to claim 7, characterized in that: The intelligent control platform (31) is also equipped with a touch operation panel (311), an emergency brake button (312) and a pressure overload alarm light (313). The touch operation panel (311) is located on the front inclined surface of the intelligent control platform (31), and the pressure overload alarm light (313) and the emergency brake button (312) are arranged sequentially above the touch operation panel (311) along the height direction.

9. A high-strength intelligent compaction method for granular materials applied to the expandable multi-compressor and separable multi-cavity compactor as described in claim 8, characterized in that, The specific steps are as follows: S1. Fill the granules into the longitudinally separated circular mold (22) and lock the mold. The linkage control group (32) initializes the pressing pressure and holding pressure parameters of the corresponding station. S2. Output instructions to the intelligent control platform (31) to drive the upper pressure head (213) to apply a preset pressing pressure to the granules through the servo electric cylinder (212), and collect sample density data in real time by the intelligent sensor (4) set at the bottom of the longitudinally separated ring mold (22) during the pressing process. S3, the linkage control group (32) and the intelligent sensor (4) input the collected density data to the intelligent control platform (31) for processing and calculate the rate of change of sample density over time. S4. When the density change rate is continuously lower than the first threshold for a preset time, the linkage control group (32) automatically determines that the sample has reached a stable molding state, and the intelligent control platform (31) issues an instruction to control the servo electric cylinder (212) through the linkage control group (32) to end the pressure holding process. S5. After the stable molding state is determined, the linkage control group (32) generates a demolding permission signal, which allows the locking mechanism (223) of the longitudinally separated ring mold (22) to unlock and perform separation demolding, thereby realizing the non-destructive removal of the granular sample.

10. The high-strength intelligent compaction method for granular materials using a scalable multi-compressor and a separable multi-cavity system according to claim 9, characterized in that: In step S4, the first threshold is the absolute value threshold of the density change rate. When the density change of the sample per unit time is less than the threshold, the sample is determined to enter the density stability stage. In step S5, before generating the demolding permission signal, the linkage control module is used to detect the locking state of the longitudinally separated ring mold (22). Only when the mold locking mechanism is detected to be in a fully locked state is the pressing termination judgment step and the demolding permission step allowed to be executed. In step S2, when the device includes multiple independent pressing and demolding units (2), the linkage control group (32) executes the pressing termination judgment step and the demolding permission step according to the station status of each independent pressing and demolding unit (2), so that different stations run asynchronously and do not interfere with each other in the mold loading, pressing and demolding stages.

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