Flexible feeding low-damage core diameter fixing and polishing device and polishing method

Abstract

The application discloses a flexible feeding type low-damage core diameter fixing and polishing device and a polishing method, and belongs to the technical field of core processing equipment. The device is composed of a core rotating driving module, a pneumatic flexible feeding module, a diameter limiting control module, a waterway cooling module, a piezoelectric ceramic actuator and a safety protection module. The core rotating driving module controls the clamping force through a pressure sensor, realizes core clamping and stable rotation, and avoids periodic damage through slight swinging of the actuator. The pneumatic flexible feeding module drives the flexible feeding of the diamond sand plate through a cylinder and a return spring, cooperates with an arc-shaped working surface and a multi-granularity design, and is suitable for polishing requirements of cores with different lithology. The diameter limiting control module realizes diameter fixing and polishing and automatic shutdown and resetting through a precise scale and a touch point type electric control limiter. The device has the characteristics of low damage, high precision and uniform polishing, is widely applicable, safe and convenient to operate, and is suitable for core pretreatment operations in the fields of geological exploration and oil exploitation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of core processing equipment, and particularly relates to a flexible feeding type low-damage core diameter fixing polishing device and a polishing method. BACKGROUND

[0002] In the experimental research in the fields of rock mechanics, geological exploration and oil and gas reservoir development, obtaining a standard core sample with accurate geometric size and maximum preservation of the integrity of the original microstructure is a necessary prerequisite for carrying out high-precision industrial CT scanning, permeability measurement and micro-pore structure analysis. The reliability of subsequent analysis techniques highly depends on the surface finish, diameter consistency and the integrity of the internal structure of the core sample. Research shows that even micron-level surface defects or structural damage can lead to experimental data distortion, and thus affect the accurate judgment of the true characteristics of the stratum rock mass.

[0003] At present, core diameter fixing preparation technologies mainly fall into two categories: traditional rigid processing technology (such as bench lathe cutting) and manual / semi-automatic polishing technology. The bench lathe cutting adopts a hard tool to perform point contact turning on a rotating core, which has a high processing efficiency, but the cutting force is concentrated, which can easily induce micro-cracks or even macro-fractures in brittle and heterogeneous cores (such as shale and loose sandstone), and seriously damages the in-situ mechanical characteristics and pore structure of the core. The manual or sandpaper polishing can partially reduce the impact damage, but it is highly dependent on the experience of the operator, and has problems such as low processing efficiency, difficult control of size accuracy, large deviation of the roundness of the sample, and lack of comparability of experimental data of different batches or different sections of the same core.

[0004] In order to solve the damage problem of rigid processing, relevant technical fields have appeared targeted improvement schemes, but most of the existing schemes continue the basic ideas of "tool rotation, workpiece feeding" or "workpiece rotation, tool feeding". For example, the "micro core sample clamping and polishing device and coaxial polishing method thereof" disclosed in Chinese patent CN109277892 A adopts a polishing method of core fixation and rotating grinding wheel feeding, which can reduce the damage risk of the core to a certain extent. However, there are still significant technical defects: first, the tangential linear velocity of the rotating grinding wheel is high, and a large tangential impact force will still be generated in the contact moment, and the damage risk of the low-strength brittle core such as argillaceous cementation loose sandstone and shale is still prominent; second, the rotating system (motor, spindle) of the grinding wheel has large rotational inertia and slow response, and even if an elastic component is provided, the buffering effect is limited, and it is difficult to realize true flexible constant force contact, and the controllability of the polishing pressure is poor; third, this scheme relies on the accurate calibration of the coaxiality of the grinding wheel and the core, and the clamping centering requirement is strict, and the diameter control relies on manual monitoring or simple mechanical limiting, and the precision is insufficient, and it is difficult to balance the two core demands of accurate diameter fixing and ultra-low damage.

[0005] In summary, existing technologies, whether traditional rigid machining, manual grinding, or improved rotary grinding, all suffer from inherent contradictions: rigid machining offers high precision but causes significant damage; manual grinding causes less damage but lower precision; and while rotary grinding attempts to balance these two aspects, it is limited by the mechanical characteristics of tool rotation, failing to address the core issues of tangential impact damage and precise constant force control. Therefore, there is an urgent need for a novel core grinding device with a fixed diameter, which, by reconstructing the interaction between the tool and the workpiece, achieves gentle and controllable low-stress grinding, fundamentally overcoming the technical bottleneck of the difficulty in simultaneously achieving high precision and low damage. Summary of the Invention

[0006] To address the problems of traditional core grinding devices, such as rigid feed leading to structural damage like edge chipping and microcracks in brittle cores, low grinding accuracy at fixed diameters, poor batch processing consistency, easy formation of periodic spiral grinding marks on the surface, limited adaptability, and insufficient operational safety, this invention aims to provide a flexible feed type low-damage core grinding device at fixed diameters. By integrating three core modules—core rotation drive, pneumatic flexible feed, and precise diameter limiting—and combining them with water cooling, micro-oscillation assistance, and a multi-layered safety protection structure, it achieves low-damage, high-precision, and uniform core grinding. This meets the stringent requirements for core pretreatment in fields such as geological exploration, oil extraction, and geotechnical engineering.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a flexible feed type low-damage core fixed-diameter grinding device, comprising: a core rotation drive module, used to drive the core to rotate around its own central axis and having a core clamping function; a pneumatic flexible feed module, symmetrically distributed on both sides of the core, used to drive the grinding components to flexibly feed towards the core to achieve grinding operations; and a diameter limit control module, which cooperates with the pneumatic flexible feed module to precisely control the core grinding diameter and trigger grinding termination.

[0008] Furthermore, the core rotation drive module, the pneumatic flexible feed module, and the diameter limit control module are all located inside the outer shell of the device. The outer shell is made of transparent material, and a core loading and unloading port is provided on the side of the outer shell. A splash guard that can be flexibly opened and closed is adapted to be installed at the core loading and unloading port.

[0009] Further, the core rotating driving module comprises: a driving motor fixed to the outer shell; a driving shaft connected with the output end of the driving motor through a shaft coupling and rotatably connected with the bottom surface of the outer shell through a bearing; an upper driving wheel and a lower driving wheel coaxially fixed to the upper and lower ends of the driving shaft, respectively; a lower clamping rod connected with a fixed rod through a base at the bottom and fixed to the side wall of the outer shell at both ends; a lower driven wheel fixed to the outer periphery of the lower clamping rod and engaged with the lower driving wheel; an upper driven wheel engaged with the upper driving wheel; and an upper clamping mechanism comprising a driving rod, an upper clamping rod, a rotating threaded rod and a ratchet handle, wherein the top of the driving rod is rotatably connected with a fixed block through a bearing, the fixed block is fixed to the outer shell, and the upper driven wheel is fixed to the outer periphery of the driving rod; the upper clamping rod is slidably assembled in the driving rod, and an internal thread is arranged in the upper clamping rod; the main body of the rotating threaded rod is matched with the upper clamping rod through a threaded pair, the upper part of the rotating threaded rod is rotatably connected with the fixed block, the top outer periphery of the rotating threaded rod is provided with an external thread, a butterfly nut and an anti-skid washer are assembled, the butterfly nut is matched with the top surface of the fixed block to limit the axial displacement of the rotating threaded rod, and the ratchet handle is detachably fixed to the top of the rotating threaded rod.

[0010] Further, the bottom of the upper clamping rod is provided with an upper clamping plate, and a pressure sensor is arranged on the bottom surface of the upper clamping plate; the top of the lower clamping rod is provided with a lower clamping plate, and a ring-shaped positioning mark is arranged at the center of the clamping surface of the lower clamping plate; the upper clamping plate, the lower clamping plate and the rotating threaded rod are coaxially arranged.

[0011] Further, the outer side wall of the upper clamping rod is provided with a sliding block and a longitudinal flat key, and the inner wall of the driving rod is correspondingly provided with a sliding groove and a key groove, and the flat key is matched with the key groove to realize the circumferential linkage of the driving rod and the upper clamping rod.

[0012] Further, the pneumatic flexible feeding module comprises: a support fixed horizontally in the inner part of the outer shell, a guide groove arranged on the bottom surface of the support, and a slide arranged on both sides of the guide groove and extending along the length direction of the support; a fixed table arranged in the middle part of the support, a through hole arranged in the middle part of the fixed table for avoiding the upper clamping rod; a sliding table, one sliding table arranged on each side of the fixed table, the sliding table slidably assembled in the slide, a connecting rod arranged at the bottom of the sliding table, and the bottom end of the connecting rod extending to the lower part of the support through the guide groove; a carborundum plate, the top of the carborundum plate detachably connected with the connecting rod, the inner side of the carborundum plate being an arc-shaped working surface, and the particle size of the carborundum plate being selected from the range of 180#-600#; an air pump arranged above the support; a cylinder symmetrically assembled in the inner part of the support, the cylinder communicated with the air pump through a high-pressure air pipe, the piston rod of the cylinder connected with the corresponding side of the sliding table; and a pair of return springs, one return spring arranged between each side of the sliding table and the fixed table for driving the sliding table to retreat to the initial position when the cylinder is depressurized.

[0013] Further, the diameter limiting control module comprises: a precision scale fixed horizontally on the rear side of the support, and two precision scales symmetrically distributed between the sliding table and the fixed table along the sliding direction of the sliding table, with a polishing diameter adjustment range of Φ20 mm-Φ150 mm and a resolution of 0.1 mm; a contact type electric control limiter detachably assembled on the precision scale, with a trigger end aligned with the side surface of the sliding table and a signal output end electrically connected to the gas path electromagnetic valve through a control line, and the electromagnetic valve being connected in series to the high-pressure gas pipeline between the air pump and the air cylinder.

[0014] Further, piezoelectric ceramic actuators are arranged between the four corners of the base and the fixed rod to drive the core to realize micro-amplitude reciprocating swing of-5°~5° around the center axis thereof.

[0015] Further, the device comprises a water cooling module for delivering cooling medium to the polishing area, and the water cooling module comprises: a water tank arranged outside the outer shell and internally carrying a submersible pump; and a sprayer arranged inside the outer shell and in communication with the submersible pump through a water pipe.

[0016] Further, the device further comprises a safety protection module, which comprises: an emergency stop button with normally closed contacts and electrically connected to the power supply control end of each module; LED status indicator lights with red / green / yellow three colors corresponding to fault / emergency stop, standby / normal operation, and polishing in progress / feed adjustment working conditions, respectively; a start pedal and a reset pedal, which are connected in series in the start-up circuit of the driving motor and the air pump by using interlocking control logic, the start pedal is used for starting the collaborative polishing process of core rotation and pneumatic feeding, and the reset pedal is used for stopping the current process and controlling the pneumatic flexible feeding module to retreat to the initial position.

[0017] The application also discloses a polishing method based on the flexible feeding type low-damage core diameter limiting polishing device.

[0018] S1. Equipment pre-check and parameter pre-setting:

[0019] S1.1. Turn on the total power supply of the device, confirm that the electrical system is normal by the constant green light of the LED status indicator light, start the air pump, adjust the air pressure to the preset working pressure, and check that there is no leakage in the gas path;

[0020] S1.2. According to the lithology of the core, select the corresponding grit size of the diamond sand plate, detachably connect the diamond sand plate and the connecting rod at the bottom of the sliding table, and ensure that the arc-shaped working surface of the diamond sand plate faces the core side;

[0021] S2. Core clamping and centering calibration:

[0022] S2.1. Rotate the butterfly nut counterclockwise until it is completely separated from the non-slip washer, open the splash baffle, and rotate the handle clockwise to drive the upper clamp rod upward, so that the distance between the upper and lower clamps is greater than the length of the core;

[0023] S2.2. Place the core on the clamping surface of the lower clamp, adjust the position of the core by the annular positioning mark in the center of the lower clamp so that the center of the core coincides with the center of the mark, and complete the initial centering;

[0024] S2.3. Rotate the handle counterclockwise to drive the upper clamp downward until the pressure sensor at the bottom of the upper clamp detects that the clamping force reaches the preset range of 5 N-10 N, stop rotating the handle and lock the butterfly nut, and close the splash baffle of the outer shell;

[0025] S3. Flexible polishing and diameter control:

[0026] S3.1. According to the target diameter of the core to be polished, set the position of the touch-controlled limit switch on the precision scale, and preset the maximum inward distance of the sliding table;

[0027] S3.2. Step on the start pedal of the safety protection module, simultaneously start the drive motor of the core rotation drive module, the submersible pump of the water cooling module, and the air cylinder of the pneumatic flexible feeding module. At this time, the LED status indicator light changes from green to yellow, indicating that the equipment is in polishing state;

[0028] S3.3. The core rotates around its central axis, the water cooling module starts, the air cylinder pushes the sliding table to flexibly feed along the slide to the core, the diamond plate arc working surface contacts and starts to polish the core surface, and the piezoelectric ceramic actuator drives the core to realize-5°~5° micro reciprocating swing, and the water mist sprays cover the polishing area;

[0029] S3.4. When the core diameter is polished to the target value, the sliding table side contacts and triggers the touch-controlled limit switch, the limit switch sends a signal to the air circuit electromagnetic valve, the electromagnetic valve switches to exhaust state, the compressed air in the air cylinder is discharged, the sliding table is reset under the action of the return spring, the drive motor and the submersible pump are stopped in turn, and the LED status indicator light changes from yellow to green, indicating that the polishing work is completed;

[0030] S4. Core removal and equipment cleaning:

[0031] S4.1. After the equipment is completely stopped, open the splash baffle, unlock the butterfly nut, and move the upper clamp upward by the handle to remove the core and detect the diameter accuracy and surface quality;

[0032] S4.2. Turn off the main power, clean the debris and water in the outer shell, blow off the residual particles on the sliding table slide and diamond plate surface, and complete the equipment maintenance.

[0033] The beneficial effects of the present application are:

[0034] 1、The core diameter straightening and polishing device disclosed in the present application adopts a pneumatic flexible feeding structure driven by a pneumatic cylinder, and the elastic buffering effect of a return spring is matched, so that the diamond sand plate and the core surface are kept in flexible surface contact instead of traditional point contact or high-speed tangential impact. The feeding pressure is accurately controlled through a controllable air pressure of 0.6-0.8 MPa, and the damage of the tangential impact force to the core is completely avoided. At the same time, the pressure sensor at the bottom of the upper clamping plate can monitor the clamping force in real time, strictly control the clamping strength, and prevent the core structure from being damaged due to excessive clamping. Even for low-strength and fragile cores such as argillaceous cementation loose sandstone and shale, the original microstructure integrity can be maximally maintained, the core contradiction of "high precision and low damage" in the prior art is solved, and the unification of low damage and high precision is realized.

[0035] 2、The present application can accurately set the target diameter of the core through the synergistic effect of the precision scale of the diameter limiting control module and the touch point type electric control limiter. The automatic stop mechanism of the limit triggered by the sliding table is used to realize high-precision control of the core diameter error ≤0.1 mm. In addition, the sliding table and the diamond sand plate symmetrically distributed on both sides, together with the annular positioning mark of the lower clamping plate and the strict coaxial design, can ensure uniform polishing of the core circumferential surface without complex centering calibration, and significantly improve the diameter consistency during batch processing.

[0036] 3、In the present application, the diamond sand plate adopts a multi-granularity optional design of 180#-600#, and the arc-shaped working surface can accurately adapt to the cylindrical surface of the core, reducing the polishing dead angle. At the same time, the-5°~5° micro-amplitude reciprocating swing realized by the piezoelectric ceramic actuator can effectively break the periodic cutting trajectory of the abrasive grains, and eliminate the spiral scratches from the root, thereby improving the polishing quality and process adaptability of the core surface.

[0037] 4、The present application integrates an effective cooling and protection mechanism. The water mist spraying of the waterway cooling module not only can cool the polishing area to avoid the influence of high temperature on the core structure and the diamond sand plate, but also can clean the debris generated during polishing together with the splash baffle to reduce the secondary damage of the debris to the polished surface. Combined with the adaptive selection of diamond sand plates of different granularities, the surface roughness of the core can meet the stringent requirements of subsequent experiments such as strength test and permeability test.

[0038] 5、In the present application, the safety protection module constructs a three-layer protection system of emergency stop button, foot pedal interlocking combined state indicator light. The foot switch realizes convenient start and stop of the equipment, the emergency stop button can instantaneously cut off the power of the whole system, and the three-color indicator light feedback standby, polishing and fault three working conditions, so that the operator can intuitively master the equipment state, and the operation risk is greatly reduced.

[0039] 6、The application can widely adapt to the core polishing needs of different lengths, diameters and lithology (brittleness, compactness, etc.) by adjusting the clamping distance, replacing different grit sand plates, adjusting the core rotation speed and swing frequency, effectively solving the problem of single adaptability of traditional devices; at the same time, the transparent shell body facilitates the real-time observation of the polishing state by the operator, timely adjustment of parameters or handling of abnormal conditions, and is suitable for core pretreatment operations in many fields such as geological exploration, oil exploitation, geotechnical engineering, etc., and has a wide application scenario. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a front view schematic diagram of a flexible feeding type low-damage core diameter fixing polishing device.

[0041] Figure 2 It is a centering relationship diagram of the upper clamp plate and the lower clamp plate.

[0042] Figure 3 It is an isometric view of the lower clamp plate.

[0043] Figure 4 It is an isometric view of the pneumatic flexible feeding module.

[0044] Figure 5 It is an isometric view of the diamond sand plate.

[0045] Among them, 1 is an outer shell, 2 is a core rotation driving module, 3 is a pneumatic flexible feeding module, 4 is a diameter limiting control module, 5 is a water cooling module, 6 is a piezoelectric ceramic actuator, and 7 is a safety protection module.

[0046] 11 is a splash guard.

[0047] 21 is a driving motor, 22 is a driving shaft, 23 is an upper driving wheel, 24 is a lower driving wheel, 25 is an upper driven wheel, 26 is a lower driven wheel, 27 is a lower clamping rod, 28 is an upper clamping mechanism, and 29 is a base.

[0048] 271 is a lower clamp plate, and 272 is an annular positioning mark.

[0049] 281 is a driving rod, 282 is an upper clamping rod, 283 is a rotating threaded rod, 284 is a crank handle, 285 is a fixed block, 286 is a butterfly nut, 287 is an anti-slip washer, 288 is an upper clamp plate, and 289 is a pressure sensor.

[0050] 31 is a support, 32 is an air pump, 33 is an air cylinder, 34 is a return spring, 35 is a sliding table, 36 is a diamond sand plate, 37 is a fixed table, 38 is a through hole, and 39 is a connecting rod.

[0051] 41 is a touch type electric control limiter, and 42 is a precision scale.

[0052] 51 - water tank, 52 - DC 12V submersible pump, 53 - water pipe, 54 - sprinkler;

[0053] 71 - emergency stop button, 72 - LED status indicator, 73 - reset pedal, 74 - start pedal. DETAILED DESCRIPTION

[0054] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions of the present application will be further described below in combination with the drawings and examples.

[0055] Example 1

[0056] The present embodiment discloses a flexible feeding low-damage core diameter fixing and polishing device, referring to Figures 1-4 The device is composed of an outer shell 1, a core rotating drive module 2, a pneumatic flexible feeding module 3, a diameter limiting control module 4, and a water cooling module 5, which work together to realize low-damage diameter fixing and polishing of the core.

[0057] In order to facilitate the placement of the core to be polished and the removal of the polished core, a core taking and placing opening is formed on the side surface of the outer shell 1. At the same time, in order to prevent the flying of rock debris, dust and other debris generated during polishing to the outside of the device, polluting the working environment or causing safety hazards, a flexible opening and closing splash-proof baffle 11 is installed at the core taking and placing opening. The baffle is connected by hinge type (or sliding type structure), which is convenient to open and close, and can be tightly fitted with the edge of the taking and placing opening when closed, forming an effective protective barrier.

[0058] In order to facilitate the operator to observe the core polishing process in real time (especially the dynamic cooperation of the core rotating drive module driving the core to rotate and feed polishing), to find out the problems such as core centering deviation, uneven surface polishing, and debris accumulation in time, so as to quickly adjust the parameters or trigger emergency response, the outer shell 1 is made of transparent material with high transparency and high strength (such as polycarbonate PC plate or acrylic plate, without limitation on the specific preparation material type).

[0059] The core rotating drive module 2 is the core power component for driving the core to rotate and polish, which is composed of a driving motor 21, a driving shaft 22, an upper driving wheel 23, a lower driving wheel 24, an upper driven wheel 25, a lower driven wheel 26, a lower clamping rod 27, and an upper clamping mechanism 28, which work together to realize stable rotation and accurate clamping of the core. The specific structure is as follows:

[0060] The driving motor 21 is fixedly installed on the outer shell 1 as a power source; the driving shaft 22 is rigidly connected with the output end of the driving motor 21 through a shaft coupling, rotates under the driving of the driving motor 21, and the bottom end of the driving shaft 22 is rotatably connected with the bottom surface of the outer shell 1 through a bearing, so as to ensure the coaxiality and stability when the driving shaft 22 rotates. The upper driving wheel 23 and the lower driving wheel 24 with the same diameter specification are coaxially fixed on the upper and lower ends of the driving shaft 22 respectively, and when the driving shaft 22 rotates, the upper driving wheel 23 and the lower driving wheel 24 are synchronously driven to rotate at the same speed, so as to provide power for the transmission mechanisms on the upper and lower sides.

[0061] The upper clamping mechanism 28 is composed of a driving rod 281, an upper clamping rod 282, a rotating threaded rod 283, a handle 284, a butterfly nut 286 and an anti-skid washer 287.

[0062] The upper driven wheel 25 is fixedly installed on the outer circumferential surface of the driving rod 281, the top of the driving rod 281 is rotatably connected with a fixed block 285 through a bearing, the fixed block 285 penetrates through the top surface of the outer shell 1 and is fixedly connected with the outer shell 1, so as to provide stable axial support for the driving rod 281.

[0063] The upper driving wheel 23 is engaged with the upper driven wheel 25, when the driving motor 21 drives the upper driving wheel 23 to rotate, the upper driven wheel 25 is synchronously driven to rotate through the engagement transmission, and then the driving rod 281 fixedly connected with the upper driven wheel 25 is driven to rotate, so as to lay a power transmission foundation for the rotation of the rock core.

[0064] The upper clamping rod 282 is assembled in the driving rod 281 in a sliding connection mode, in order to realize the accurate up-down movement adjustment of the upper clamping rod 282, the inner thread is pre-assembled in the upper clamping rod 282, and the upper part thereof is matched with the rotating threaded rod 283 through a threaded pair, the top of the rotating threaded rod 283 is rotatably connected with the fixed block 285 through a bearing, specifically: an annular shaft shoulder is arranged on the upper part of the rotating threaded rod 283, a deep groove ball bearing is matched with a bearing seat in the fixed block 285 below the shaft shoulder, and the outer ring of the bearing is limited by the shaft shoulder retainer, so as to ensure that the rotating threaded rod 283 can freely rotate around the axis in the circumferential direction and cannot axially move.

[0065] The rotating threaded rod 283 is coaxially arranged with the driving rod 281, the top thereof is designed as a hollow structure, and the handle 284 is assembled in the hollow structure in a plug-in fixed mode, the connection form is convenient for the quick installation and disassembly of the handle 284; the operator can drive the rotating threaded rod 283 to rotate by rotating the handle 284, and the upper clamping rod 282 is pushed to stably move up and down in the driving rod 281 by the mechanical action of the threaded transmission, so as to flexibly adjust the distance between the upper clamping mechanism 28 and the lower clamping rod 27, and adapt to rock cores with different length specifications.

[0066] To realize the axial position limit of the rotating threaded rod 283 (prevent the threaded pair from loosening due to polishing vibration), an outer thread is processed on the outer circumferential surface of the hollow section at the top of the rotating threaded rod 283, and a butterfly nut 286 and an anti-skid washer 287 are assembled in a matched manner; after adjusting the upper clamping rod 282 to the rock core clamping position, the butterfly nut 286 is rotated clockwise, so that it is tightly attached to the top surface of the fixed block 285 through the anti-skid washer 287, and only the friction force is used to limit the axial displacement of the rotating threaded rod 283, without affecting the circumferential rotation, so as to ensure that the rotation power transmission is not disturbed.

[0067] To monitor the clamping force of the rock core in real time and avoid damage to the rock core due to excessive clamping force, an upper clamping plate 288 is fixedly arranged at the bottom of the upper clamping rod 282, and a pressure sensor 289 is installed on the bottom surface of the upper clamping plate 288. The pressure sensor 289 can collect and feed back the actual pressure value in the clamping process in real time, so as to provide accurate data support for the operator to control the clamping force, and further ensure the structural integrity of the rock core.

[0068] The lower driven wheel 26 is coaxially fixed on the outer circumferential surface of the lower clamping rod 27, and the diameter of the lower driven wheel 26 is the same as that of the upper driven wheel 25, so as to ensure that the transmission rotation speeds of the upper and lower sides are completely matched; the top of the lower clamping rod 27 is coaxially fixedly installed with a lower clamping plate 271, which forms an opposite clamping mechanism with the upper clamping plate 288, so as to realize the stable clamping and fixing of the rock core; the bottom of the lower clamping rod 27 is fixed on the base 29, and the base 29 is fixed on the horizontally arranged fixed rod, and the two ends of the fixed rod are fixedly connected with the side wall surfaces of the outer shell body 1, so as to provide stable support for the lower clamping rod 27 and ensure the structural stability when the upper and lower clamping plates clamp the rock core.

[0069] As a preferred structure, to avoid the rotation deviation of the upper clamping rod 282 during the upward and downward movement, and to ensure smooth transmission of the rotation power, a sliding block and a longitudinal flat key are arranged on the outer side wall of the upper clamping rod 282; correspondingly, a longitudinally extending sliding groove is formed in the inner wall of the driving rod 281 at a position corresponding to the sliding block, and a key groove is also formed in the sliding groove. The cooperation of the sliding block and the sliding groove limits the circumferential rotation deviation of the upper clamping rod 282, and the cooperation of the flat key and the key groove realizes the forced circumferential linkage of the driving rod 281 and the upper clamping rod 282; at the same time, the internal thread in the upper clamping rod 282 and the external thread of the rotating threaded rod 283 are designed in a clearance fit, so as to ensure that the upper clamping rod 282 can smoothly drive the rotating threaded rod 283 to rotate synchronously in the circumferential direction when the upper clamping rod 282 rotates, and form a complete rotation power transmission closed loop.

[0070] As a preferred solution, to ensure the centering of the core clamping from the structural root, it is necessary to strictly ensure that the upper clamp plate 288, the lower clamp plate 271 and the rotating threaded rod 283 are coaxially arranged: the upper clamp plate 288 is coaxially assembled with the rotating threaded rod 283, and the axis line of the lower clamp plate 271 is completely coincident with that of the upper clamp plate 288. Through this accurate coaxial design, the deviation of the core clamping from the center caused by the position deviation of the clamp plate is avoided from the root.

[0071] Meanwhile, an annular positioning mark 272 is additionally arranged at the center position of the clamping surface of the lower clamp plate 271. In the embodiment, a 1 mm wide annular line is preferably used as the positioning mark, which is processed by high-precision laser engraving process. The edge of the line is flat and has high definition, which is convenient for the operator to quickly identify. When the operator places the core to be polished on the lower clamp plate 271 to prepare for the subsequent polishing operation, the alignment of the bottom edge of the core with the annular line can be directly observed to quickly adjust the position of the core, so that the center of the core is coincident with the center of the line. This can effectively reduce the positioning error caused by visual judgment deviation during manual placement, and further improve the initial centering accuracy before the core clamping.

[0072] The pneumatic flexible feeding module 3 is the core component for realizing the core polishing feeding action, and bears the key function of approaching and contacting the diamond sand plate to the core. It is composed of a bracket 31, a gas pump 32, a gas cylinder 33, a return spring 34, a sliding table 35 and a diamond sand plate 36. The assembly relationship of each part is as follows:

[0073] The horizontally arranged bracket 31 is used as the basic support structure of the module, and its two ends are fixedly connected with the inner side of the outer shell 1 through support rods. The connection parts of the support rods, the bracket 31 and the outer shell 1 are reinforced by bolts to ensure that the bracket 31 does not shake during the operation of the device, and to provide a stable reference for the subsequent feeding action. A guide groove extending along the length direction of the bracket is arranged at the middle position of the bottom surface of the bracket 31. Meanwhile, strip-shaped sliding tracks extending along the length direction of the bracket 31 are arranged on both sides of the guide groove on the bottom surface of the bracket 31. The sliding tracks provide directional constraint for the movement of the sliding table 35, avoiding deviation or jamming of the sliding table 35 during movement.

[0074] Two ends of the bracket 31 are respectively equipped with a sliding table 35, the bottom of the sliding table 35 is in clearance fit with the slide, and can smoothly slide along the slide; a fixed table 37 is fixedly arranged at the central position of the bracket 31, the fixed table 37 is integrally processed or welded with the bracket 31, and the structural rigidity is ensured. A return spring 34 is arranged between each sliding table 35 and the fixed table 37, both ends of the return spring 34 are connected with the sliding table 35 and the fixed table 37 through spring seats, and the return spring 34 is in a natural elongation state in an initial state. When the sliding table 35 moves towards the fixed table 37, the return spring 34 is compressed and stores elastic potential energy, and after the driving force of the sliding table disappears, the return spring 34 pulls the sliding table 35 to move away from the fixed table 37 through the elastic return force, and finally returns to the initial position, realizing the flexible return of the sliding table 35 and avoiding the impact on the parts caused by the rigid return.

[0075] A longitudinal through circular through hole 38 is formed in the middle of the fixed table 37, the diameter of the through hole 38 is slightly larger than the outer diameter of the upper clamping rod 282, and the core role of the through hole 38 is to avoid the upper clamping rod 282: after the upper clamping rod 282 passes through the through hole 38, the lower end of the upper clamping rod 282 is fixedly connected with the upper clamping plate 288 arranged below the bracket 31, which does not affect the upward and downward movement of the upper clamping rod 282 through threaded transmission, and avoids the interference between the upper clamping rod 282 and other parts of the pneumatic flexible feeding module 3, ensuring that the actions of each module are independent and coordinated.

[0076] A connecting rod 39 is vertically fixed at the central position of the bottom of the sliding table 35, the lower end of the connecting rod 39 extends to below the bracket 31 through the guide groove, the connecting rod 39 is welded or screw-connected with the sliding table 35, and the connecting strength is ensured. An external thread is formed on the bottom outer circumferential surface of the connecting rod 39, and an internal thread hole is formed in the top of the carborundum plate 36, and the two are detachably connected through the threaded connection, so that different specifications of the carborundum plate 36 can be quickly replaced on the same set of devices to adapt to different polishing requirements. The carborundum plates 36 on both sides are symmetrically distributed on both sides of the upper and lower clamping plates, so that the rock core on both sides is uniformly polished at the same time. The granularity of the carborundum plate 36 can be selected in the range of 180#-600#, and the inner side working surface of the carborundum plate 36 is prefabricated into an arc profile, the curvature of the arc profile can be designed according to the diameter of the common rock core, which can better fit the cylindrical surface of the rock core, cover the circumferential surface of the rock core, reduce the polishing dead angle, and improve the uniformity of the rock core surface polishing.

[0077] The air pump 32 is fixedly installed above the support 31 as a power source of the feeding action, and the output end thereof is sealingly connected with the air inlet of the air cylinder 33 through a high-pressure air pipe. The air cylinder 33 is symmetrically arranged inside the support 31: two air cylinders 33 are fixed on the inner side walls at both ends of the support 31 through air cylinder seats, and the axis of the air cylinder 33 is consistent with the extension direction of the slide way; and the end of the piston rod of each air cylinder 33 is rigidly connected with the side of the slide table 35 on the corresponding side through a flange or a pin shaft (a buffer pad is additionally arranged at the connection position to reduce the impact during power transmission).

[0078] When the air pump 32 is started, compressed air is generated and delivered into the air cylinder 33 through the high-pressure air pipe, the compressed air drives the piston rod of the air cylinder 33 to extend outward, the piston rod drives the slide table 35 connected therewith to move along the slide way to the direction close to the core, until the arc-shaped working surface of the diamond plate 36 is in contact with the rotating core surface, at this time, the polishing feeding action starts; if it is needed to adjust the polishing feeding amount (i.e. the contact pressure of the diamond plate and the core), the extension length of the piston rod of the air cylinder can be controlled by adjusting the output air pressure of the air pump 32 (the air pressure range can be set as 0.6-0.8 MPa), the higher the air pressure is, the longer the piston rod extends, the greater the moving distance of the slide table 35 is, the greater the contact pressure of the diamond plate and the core is, and the higher the polishing efficiency is; on the contrary, the smaller the contact pressure is, which is suitable for the polishing of the fragile core and other damaged samples, and effectively avoids the core surface from being cracked or the diameter from being out of tolerance due to the excessive feeding amount. When the polishing is completed (such as the diameter limiting control module 4 is triggered) or needs to be paused, the air pump 32 stops supplying air, the compressed air in the air cylinder 33 is quickly discharged through an exhaust valve, the piston rod of the air cylinder loses the air pressure support, at this time, the reset spring 34 releases the stored elastic potential energy, pulls the slide table 35 to reset to the direction away from the core, and the piston rod of the air cylinder 33 is also driven to retract by the slide table, thereby completing a complete feeding-polishing-resetting cycle.

[0079] The present application utilizes the air cylinder 33 to realize flexible feeding, the core of which is based on the compressibility of compressed air and the elastic adjustment of the reset spring: when the piston rod of the air cylinder 33 is driven to extend by compressed air, the compressed air can be slightly adjusted in pressure according to the actual condition of the core surface (such as the small protrusions on the core surface and the roundness error), when the diamond plate 36 contacts the protruding part of the core surface, the compressed air is slightly compressed, the extension speed of the piston rod of the air cylinder is slowed down, and the damage to the core caused by rigid impact is avoided; at the same time, the reset spring 34 is always in a slightly compressed state, provides a reverse elastic pulling force for the slide table 35, and makes the diamond plate 36 and the core surface keep flexible contact instead of rigid compression, thereby ensuring that the contact pressure is stable and adjustable during the polishing process, and adapting to the polishing requirements of cores with different lithology.

[0080] The advantages of this flexible feeding mode compared with the traditional rigid feeding polishing structure are as follows:

[0081] Effective protection of brittle rock cores: Traditional rigid feed (such as screw drive) is prone to cracking and micro-cracks on the surface of the rock core due to uncontrollable pressure. However, the cylinder flexible feed can precisely control the contact pressure within a safe range through the dual adjustment of air pressure and spring, which is especially suitable for low-damage grinding of brittle rock cores such as shale and coal.

[0082] Adaptive surface morphology improves grinding uniformity: If the core has roundness error or uneven surface, rigid feed will cause local over-grinding or under-grinding. However, the flexible feed of the cylinder can use a small amount of compressed air to buffer the diamond plate to keep it in contact with the core surface, ensuring uniform grinding of the circumferential surface and improving diameter accuracy.

[0083] Reduce accidental collision damage: During rigid feeding, if the core is accidentally deviated, it is easy to cause the diamond plate to collide rigidly with the core, resulting in chipping of the diamond plate and damage to the slide. The cylinder flexible feeding can reduce the impact force of the collision through the pressure relief of compressed air, and extend the service life of components such as diamond plate and slide.

[0084] In addition, it is easy to adjust and has wide adaptability. The feed pressure and speed can be changed simply by adjusting the air pressure valve of the air pump. There is no need to disassemble or adjust the mechanical structure. It is easy to operate and can quickly adapt to the grinding parameters of different grit diamond plates and different rock cores, thus improving work efficiency.

[0085] The diameter limit control module 4 is a key component that ensures the precision of core grinding. It works in conjunction with the pneumatic flexible feed module 3. The module consists of a contact-type electronically controlled limiter 41 and a precision scale 42. The two work together to precisely control the core grinding diameter.

[0086] The precision scale 42, as the core component for diameter preset and distance monitoring, is horizontally mounted on the rear side of the bracket 31 and adopts a symmetrical layout. That is, a precision scale 42 is set between each slide 35 and the fixed platform 37 to ensure that the movement distance of the two slides 35 can be independently monitored and calibrated. The scale on it is used to preset the target grinding diameter. The grinding diameter adjustment range is Φ20 mm-Φ150 mm with a resolution of 0.1 mm. The operator can accurately preset the maximum inward distance of the slide 35 (i.e., the contact grinding depth between the diamond plate 36 and the surface of the rock core) according to the target diameter of the rock core to be ground, and mark the limit position of the slide 35 with the scale as a reference, providing a precise physical reference for the subsequent adjustment of the contact-type electronic limiter 41.

[0087] Each of the two precision scales 42 is detachably equipped with a contact-type electrically controlled limiter 41 (in this embodiment, the contact-type electrically controlled limiter 41 is fixed to the bracket 31 by bolts), and its fixed position can be adjusted along the length of the scale. The trigger point of the contact-type electrically controlled limiter 41 faces the side of the slide table 35, and the height of the trigger contact is aligned with the contact position on the side of the slide table 35, ensuring that the slide table 35 can accurately contact the contact point when it moves. Its signal output terminal is electrically connected to the solenoid valve in the air circuit system through a control line, and the solenoid valve is connected in series in the high-pressure air pipeline between the air pump 32 and the cylinder 33. The specific control process is as follows:

[0088] The operator calculates the maximum inward distance of the slide table 35 based on the target grinding diameter and the scale of the precision ruler 42. Then, the operator adjusts the fixed position of the contact-type electronic limiter 41 along the length of the ruler so that the slide table 35 can just touch the trigger contact of the limiter when it moves to the preset distance. After adjustment, the limiter is fixed to ensure that the limit position does not deviate.

[0089] Initially, the air circuit solenoid valve is in the air intake open state. Compressed air output from the air pump 32 can enter the cylinder 33 through the solenoid valve, pushing the piston rod to extend and causing the slide table 35 and the diamond abrasive plate 36 to move towards the rock core. The diamond abrasive plate 36 then approaches the surface of the rock core, and the grinding operation begins. During the grinding process, the diameter of the rock core continues to decrease as grinding progresses. Under the driving force of the cylinder 33, the slide table 35 continues to move inward towards the rock core, while the side of the slide table 35 gradually approaches the trigger contact of the contact-type electronic control limiter 41.

[0090] When the core diameter reaches the preset value, the slide table 35 moves to the preset maximum inward distance, and its side contacts the trigger contact of the contact-type electronic limit switch 41. After the limit switch is triggered, it immediately generates an electrical signal and transmits it to the air circuit solenoid valve through the control line. After receiving the electrical signal from the limit switch, the solenoid valve immediately switches its working state from air intake conduction to exhaust conduction: on the one hand, it cuts off the air intake channel from the air pump 32 to the cylinder 33, and on the other hand, it opens the exhaust channel between the cylinder 33 and the outside. The compressed air in the cylinder 33 is quickly discharged through the solenoid valve. After the air pressure disappears, the slide table 35 moves away from the core under the elastic tension of the return spring 34, and at the same time drives the cylinder piston rod to retract. Until the slide table 35 returns to the initial position, the entire grinding and resetting process is completed, effectively avoiding the core diameter from being too small due to over-grinding, and ensuring the consistency of the grinding diameter of each batch of cores.

[0091] The diameter limiting control module 4 is designed by combining mechanical reference (precision scale) and electric control trigger (limiting device), which can ensure the accuracy of the core polishing diameter (error ≤0.1mm) and realize automatic reset after polishing, effectively avoiding the problem of excessive polishing or insufficient polishing caused by manual monitoring; at the same time, the independent limiting control on both sides can adapt to the possible "initial diameter asymmetry" of the core, and by adjusting the position of the unilateral limiting device, the uniformity of the core circumference polishing is ensured, and the consistency of the polishing diameter of each batch of cores is further improved.

[0092] In order to further improve the uniformity of the polished surface of the core and enhance the adaptability of the system to the small centering error, a piezoelectric ceramic actuator 6 is respectively arranged between the four corners of the base 29 and the fixed rod. The core rotates around its center axis under the drive of the core rotation driving module 2, and at the same time, through the accurate drive of the piezoelectric ceramic actuator 6, a small angle of reciprocating swing can be superimposed on the original rotation, the swing angle range is controlled between-5°~5°, and the swing frequency can be flexibly adjusted according to the polishing requirements (both high-frequency swing and controllable low-frequency swing are supported), which is suitable for different core materials (such as low-frequency slow swing for brittle core and high-frequency fast swing for dense core) and polishing precision requirements.

[0093] From the perspective of polishing effect optimization, if the core only rotates at a uniform speed in one direction, the fixed diamond plate 36 will form a "fixed track cutting effect" on the core surface: the cutting points of the diamond plate 36 abrasive grains are periodically distributed relative to the core rotation track, which is easy to leave spiral scratches on the core surface along the rotation direction (especially when the core rotation speed and the diamond plate 36 feed amount are fixed, the periodicity of the scratches is more obvious), which directly affects the surface finish; after superimposing a small reciprocating swing on the core through the piezoelectric ceramic actuator 6, the rotation track of the core will produce a small deviation, which can disrupt the fixed period of the abrasive cutting in real time, making the abrasive cutting point distribution on the core surface more random and uniform, effectively weakening or even eliminating the spiral scratches, and significantly improving the surface quality after core polishing.

[0094] At the same time, the small swing design can also improve the robustness of the system: in actual operation, even if there is a small centering error between the physical rotation axis of the core and the feed reference line of the diamond plate 36 due to assembly precision deviation (such as small deviation of the coaxiality of the upper and lower clamping plates) or core roundness error, the small reciprocating swing superimposed on the core rotation can drive the core circumference to be more fully contacted with the fixed diamond plate, and the problem of local polishing caused by the centering error can be compensated by the small angle deviation of the core during the swing process, ensuring that every part of the circumference can be effectively polished, avoiding the diameter deviation caused by insufficient local polishing, and further ensuring the accuracy and consistency of the core diameter polishing.

[0095] The water cooling module 5 is composed of a water tank 51, a DC 12V submersible pump 52, a water pipe 53 and a sprayer 54, and each component cooperates to realize efficient cooling and environmental cleaning functions.

[0096] The water tank 51 is arranged outside the outer shell 1 and serves as a cooling water storage unit; the DC 12V submersible pump 52 (head 5m, flow 15L / h) is carried inside the water tank 51 and can stably provide cooling water delivery power. The cooling water is delivered to the sprayer 54 through the water pipe 53 (silicone tube) with a specification of Φ8 mm under the driving of the submersible pump. The sprayer 54 is assembled inside the outer shell 1 and fixedly installed below the support 31, and the nozzle aperture specification of the sprayer 54 is Φ1.5 mm.

[0097] During the polishing operation, the sprayer 54 continuously sprays uniform water mist: on the one hand, it can directly act on the high-speed rubbing core surface, quickly take away the heat generated by polishing, effectively reduce the core temperature, and avoid damage to the core structure or aggravation of the diamond sand plate 36 due to high temperature; on the other hand, the water mist can wet and gather the rock debris and dust generated by polishing, form a closed protection space with the splash-proof baffle 11, prevent debris from splashing, and promote the debris to be discharged along the drainage channel (not shown in the figure) at the bottom of the outer shell 1 (a drainage opening can be added according to actual needs), thereby achieving the functions of efficiently cleaning debris and keeping the working environment clean.

[0098] The polishing device is also equipped with a safety protection module 7, which realizes full-process monitoring and risk control of device operation through multi-level design of emergency shutdown, state feedback and operation interlocking. The module is composed of an emergency stop button 71, an LED state indicator 72 (red / green / yellow three colors) and two independent waterproof foot switches (IP65, DC 24V, trigger force 30-50N). The two foot switches correspond to a reset pedal 73 and a start pedal 74 respectively. The start pedal 74 is responsible for triggering device operation and adopts a normally open contact design. When not operated, the contact is disconnected to avoid accidental start. The reset pedal 73 is responsible for interrupting device operation and adopts a normally closed contact design. When normally operating, the contact remains open to ensure the timeliness of shutdown response. Through the independent operation logic of “start-reset”, the risk of accidental triggering is avoided. The LED state indicator 72 is used to feedback the device operation state in real time. Different colors correspond to different working conditions (green indicates standby / normal operation, yellow indicates polishing / feeding adjustment, and red indicates fault / emergency stop), which facilitates the operator to quickly judge the device state and handle exceptions in time.

[0099] The emergency stop button 71 adopts a normally closed contact design, the input end is connected with the device total power supply module (not shown in the figure) through a wire, and the output end is electrically connected with the power control end of the drive motor 21 of the core rotation driving module 2, the air pump 32 of the pneumatic flexible feeding module 3 and the DC12V submersible pump 52 of the water cooling module 5 respectively. Under normal working conditions, the emergency stop button 71 remains closed, the power supply path of each module is conducted, and the equipment can operate normally; when emergency situations such as core severe deviation, component abnormal noise, waterway failure and the like occur, the operator presses the emergency stop button 71, the contact is immediately disconnected, the power supply of the drive motor 21, the air pump 32 and the DC12V submersible pump 52 is cut off at the same time, and each module stops running instantly, so as to avoid the risk from expanding.

[0100] The control end of the LED status indicator 72 is connected with the state monitoring end of each functional module through a signal line: the green indicator is connected with the power-on detection end of the total power supply module, and the green light is always on after the total power supply is turned on, prompting that the equipment is in the power-on standby state and there is no basic fault in the electrical system; the yellow indicator is connected with the cylinder electromagnetic valve control end of the pneumatic flexible feeding module 3 and the drive motor speed detection end of the core rotation driving module 2, when the electromagnetic valve is in the “air conduction” state (the diamond plate 36 is polished and fed) and the drive motor reaches the working speed, the yellow light is on, accurately feeding that the equipment is in the polishing operation; the red indicator is connected with the disconnection contact of the emergency stop button 71 and the limit switch fault detection end of the diameter limiting control module 4, when any fault is triggered, the red light flashes, and the buzzer can be linked to alarm, prompting the operator that the equipment has a fault and needs to be stopped for troubleshooting, so as to avoid the risk caused by running with fault.

[0101] Two waterproof foot switches (start pedal and reset pedal) adopt “interlocking control logic”, the power supply ends of the two are connected with DC24V control power supply, and the signal output ends are commonly connected in series in the start-up loop of the drive motor 21 of the core rotation driving module 2 and the start-up loop of the air pump 32 of the pneumatic flexible feeding module 3, and the specific connection and control logic are as follows:

[0102] When the start pedal 74 is not stepped on, the normally open contact is disconnected, and the start-up loop of the drive motor 21 and the air pump 32 is not conducted; when the start pedal 74 is stepped on by the operator, the contact is closed, if the reset pedal 73 is not triggered at this time (the normally closed contact remains closed), the start-up loop is completely conducted, the drive motor 21 is started to drive the core rotation, the air pump 32 is started to drive the diamond plate 36 to feed, and at the same time the signal end of the start pedal 74 sends a signal to the control end of the yellow indicator, and the yellow light is on, feeding back that “the equipment enters the polishing state”.

[0103] When the device is in normal operation, the reset pedal 73 is not pressed, the normally closed contact remains closed, and the starting circuit is continuously on; when it is necessary to temporarily stop (such as replacing the core or cleaning the debris), the operator presses the reset pedal 73, the normally closed contact is disconnected, the starting circuit is immediately interrupted, the driving motor 21 and the air pump 32 stop working, and at the same time the signal end of the reset pedal 73 sends an interruption signal to the yellow indicator lamp control end, the yellow lamp is extinguished, the green lamp remains always on, and the device returns to standby state; after releasing the reset pedal 73, its contact is automatically reset and closed, and the device can be restarted by the starting pedal 74.

[0104] The overall operation scheme of the device is as follows:

[0105] Step 1, equipment pre-check and system initialization

[0106] 1.1, take the drilled and pretreated core sample to be polished, connect the water pipe 53 of the equipment side water cooling module 5, and ensure that the waterway is sealed and leak-free.

[0107] 1.2, according to the core lithology (such as brittle core, select coarse particle size 180#, dense core, select fine particle size 600#) and surface accuracy requirement, replace the corresponding particle size of diamond sand plate 36 through the threaded connection structure at the bottom of connecting rod 39, and ensure that the arc-shaped working surface faces the core side during installation, and the threaded connection is firm to avoid loosening during polishing.

[0108] 1.3, connect the total power supply of the device, observe the LED state indicator 72 of the safety protection module 7, at this time the standby indicator (green) should be normally lit, at the same time the electrical system automatically completes self-checking (emergency stop button 71 contact closure detection, reset pedal 73 / starting pedal 74 passage detection), if the red fault lamp does not flicker, it means that the electrical system has no basic fault.

[0109] 1.4, airway pressure test: start the air pump 32 of the pneumatic flexible feeding module 3, observe the airway pressure gauge, ensure that the pressure is stable in the range of 0.6-0.8 MPa, check that the air cylinder 33 and the air pipe interface have no leakage; simultaneously verify the zero point state of the bottom surface pressure sensor 289 of the upper clamping plate 288 (the display value should be ≤0.1N), ensure that the clamping force monitoring system works normally.

[0110] Step 2: core clamping and centering calibration

[0111] 2.1, counterclockwise rotate the butterfly nut 286 (fastening device) above the upper clamping mechanism 28 in the core rotating drive module 2 until it is completely separated from the anti-slip washer 287 on the top surface of the fixed block 285, remove the axial limitation of the rotating threaded rod 283, and pull open the openable splash-proof baffle 11 at the core taking and placing opening on the side surface of the outer shell 1.

[0112] 2.2 Insert the crank handle 284 into the hollow structure at the top of the rotating threaded rod 283, and rotate the crank handle 284 clockwise: through the threaded transmission between the rotating threaded rod 283 and the upper clamping rod 282, the upper clamping rod 282 is driven to slide upward along the sliding groove (including the keyway) on the inner wall of the drive rod 281 until the distance between the bottom surface of the upper clamping plate 288 and the top surface of the lower clamping plate 271 is greater than the length of the rock core to be installed, and the 1 mm annular positioning mark 272 at the center of the clamping surface of the lower clamping plate 271 is fully exposed, and stop rotating the crank handle 284.

[0113] 2.3 Place the core sample steadily on the lower clamping plate 271, aligning the bottom edge of the core with the annular positioning mark 272 to complete the initial centering; then slowly rotate the handle 284 counterclockwise to drive the upper clamping plate 288 downward, slowing down the rotation speed when it approaches the top of the core to avoid colliding with the core surface.

[0114] 2.4 When the bottom surface of the upper clamping plate 288 contacts the rock core and continues to descend, and the pressure sensor 289 detects that the clamping force has reached the preset value (5 N-10 N), the LED status indicator (green) of the safety protection module 7 will automatically light up to indicate that the clamping is complete. Immediately stop turning the crank handle 284 and remove the crank handle 284 from the top of the rotating threaded rod 283 to prevent it from being thrown out during subsequent rotation. Rotate the wing nut 286 clockwise until it is slightly in contact with the top surface of the fixing block 285 through the anti-slip washer 287 (it is advisable to feel a slight resistance when the hand is on it, without over-tightening). This only restricts the axial displacement of the rotating threaded rod 283 and does not affect the rotation. Close the splash guard 11 to prevent rock chips from splashing during grinding.

[0115] Step 3: Diameter setting and automated grinding

[0116] 3.1. Based on the target core diameter, refer to the precision scale 42 (resolution 0.1mm) of the diameter limit control module 4 to calculate the distance that the two slides 35 need to advance inward. Adjust the fixed position of the two contact-type electric limiters 41 so that the trigger point is aligned with the side position of the slide 35 after advancing to the target position. After adjustment, tighten the limiter bolts to prevent displacement.

[0117] 3.2 After confirming that the area around the equipment is safe, the operator presses the start pedal 74 of the safety protection module 7 (reset pedal not triggered state), and the system starts sequentially according to the preset program:

[0118] The drive motor 21 of the core rotation drive module 2 starts, driving the core to rotate around its own central axis at a set speed;

[0119] Simultaneously start the DC12V submersible pump 52 of the water cooling module 5, and spray water mist from the sprayer 54 to the core grinding area;

[0120] The electromagnetic valve of the pneumatic flexible feeding module 3 is turned on, the cylinder 33 pushes the sliding table 35 to move along the slide at the bottom of the support 31 towards the core, and the return spring 34 is compressed.

[0121] 3.3、When the arc-shaped working surface of the diamond plate 36 contacts the rotating core surface, the full-range profiling polishing begins; at the same time, the piezoelectric ceramic actuator 6 between the four corners and the fixed rod of the base 29 is started to drive the core to realize a micro-amplitude reciprocating swing of-5°~5° around its central axis, which breaks the cutting period of the abrasive particles and avoids the spiral-shaped grinding marks.

[0122] 3.4、With the polishing advancing, the diameter of the core gradually decreases, and the sliding table 35 continuously advances towards the core; when the diameter of the core reaches the target value, the side of the sliding table 35 accurately touches the triggering contact of the contact-type electric control limiter 41, the limiter immediately sends a signal to the air path electromagnetic valve, and the electromagnetic valve is switched from the air inlet to the air outlet: the air inlet of the air pump 32 to the cylinder 33 is cut off, and the cylinder exhaust passage is turned on; the compressed air in the cylinder 33 is quickly discharged, the sliding table 35 is reset to the original position under the elastic tension of the return spring 34, and the cylinder piston rod is synchronously withdrawn; after the sliding table 35 returns to the original position, the driving motor 21 and the DC12V submersible pump 52 are sequentially stopped, and the LED status indicator 72 is switched back from yellow (polishing) to green (standby).

[0123] Step 4: Core unloading and quality verification

[0124] 4.1、After the equipment is completely stopped, open the splash guard 11.

[0125] 4.2、Insert the crank 284 and rotate it clockwise, which drives the upper clamping rod 282 to rise along the groove, so that the upper clamping plate 288 is separated from the core; carefully take out the core sample to avoid touching the polished surface.

[0126] 4.3、Quality inspection:

[0127] Use the digital caliper to measure the diameter of 3 points uniformly distributed along the length of the core to confirm that the accuracy meets the requirements;

[0128] Observe the surface through a magnifying glass to see if there are micro-cracks or edge collapse (due to the flexible feeding and pressure monitoring of the device, such defects can be reduced);

[0129] Use a handheld roughness meter to detect the surface finish to verify the effect of the piezoelectric ceramic actuator 6 in eliminating spiral-shaped grinding marks.

[0130] Step 5: System cleaning and maintenance

[0131] 5.1、Close the water tank 51 valve of the water cooling module 5, sequentially cut off the power of the air pump 32, driving motor 21, and DC12V submersible pump 52, and finally turn off the main power supply, and the LED status indicator 72 is turned off.

[0132] 5.2, clean the debris and water in the outer shell 1 with special tools, and blow the residual particles on the contact surface of the bracket 31 slide, slide 35 and the surface of the diamond plate 36 with compressed air; Focus on cleaning the debris at the annular positioning mark 272 on the lower clamp plate 271, and ensure accurate centering next time.

[0133] 5.3, maintenance:

[0134] Check the flatness of the arc-shaped working surface of the diamond plate 36, and replace it through threaded connection if it is severely worn;

[0135] Clean the filter of the air path system and check whether the piston rod of the air cylinder 33 has abnormal noise;

[0136] Calibrate the value of the pressure sensor 289 on the upper clamp plate 288 to ensure accurate monitoring of the clamping force;

[0137] Check the insulation of the wiring terminal of the piezoelectric ceramic actuator 6 to ensure stable swing function.

[0138] The basic principles, main features and advantages of the present application are shown and described above. However, the above description is only a specific embodiment of the present application, and the technical features of the present application are not limited to this. Any other implementation derived by those skilled in the art without departing from the technical solution of the present application should be covered in the scope of the present application.

Claims

1. A flexible feed low-damage core diameter setting and polishing device, characterized in that, The application relates to a core polishing device. The core rotating driving module is used for driving the core to rotate around the central axis of the core and has a core clamping function. The pneumatic flexible feeding module is symmetrically distributed on the two sides of the core and is used for driving the polishing component to flexibly feed towards the core to realize polishing work. The diameter limiting control module cooperates with the pneumatic flexible feeding module and is used for accurately controlling the core polishing diameter and triggering polishing termination. The core rotating driving module, the pneumatic flexible feeding module and the diameter limiting control module are arranged inside the shell body of the device. The core rotating driving module comprises a driving motor fixed on the shell body, a driving shaft connected with the output end of the driving motor through a shaft coupling and rotatably connected with the bottom surface of the shell body through a bearing, upper and lower driving wheels coaxially fixed on the upper and lower ends of the driving shaft respectively, a lower clamping rod connected with a fixed rod through a base at the bottom and fixed on the side wall of the shell body through the fixed rod at the two ends, a lower driven wheel fixed on the outer periphery of the lower clamping rod and engaged with the lower driving wheel, and an upper driven wheel engaged with the upper driving wheel. The upper clamping mechanism comprises a driving rod, an upper clamping rod, a rotating threaded rod and a handle. The top of the driving rod is rotatably connected with a fixed block through a bearing, the fixed block is fixed on the shell body, and the upper driven wheel is fixed on the outer periphery of the driving rod. The upper clamping rod is slidably arranged in the driving rod and is internally provided with an internal thread. The main body of the rotating threaded rod is matched with the upper clamping rod through a threaded pair, the upper part of the rotating threaded rod is rotatably connected with the fixed block, the top outer periphery of the rotating threaded rod is provided with an external thread, a butterfly nut and an anti-skid washer are matched and assembled, the butterfly nut is matched with the top surface of the fixed block to limit the axial displacement of the rotating threaded rod, and the handle is detachably fixed on the top of the rotating threaded rod. The pneumatic flexible feeding module comprises a support fixed horizontally in the shell body, a guide groove arranged on the bottom surface of the support and a slide arranged on the two sides of the guide groove and extending along the length direction of the support. A fixed table is arranged in the middle of the support, a through hole is arranged in the middle of the fixed table for avoiding the upper clamping rod, and a slide table is arranged on the two sides of the fixed table. A corundum plate is detachably connected with the connecting rod at the top, the inner side of the corundum plate is an arc-shaped working surface, and the granularity can be selected in the range of 180#-600#. An air pump is arranged above the support. A cylinder is symmetrically arranged in the support and is communicated with the air pump through a high-pressure air pipe, the piston rod of the cylinder is connected with the slide table on the corresponding side, and a pair of reset springs are arranged between each slide table and the fixed table for driving the slide table to retreat to the initial position when the cylinder is depressurized. The shell body is made of transparent material, the side surface of the shell body is provided with a core taking and placing opening, and a flexible opening and closing splash-proof baffle is matched and arranged at the core taking and placing opening. The bottom of the upper clamping rod is provided with an upper clamping plate, and the bottom surface of the upper clamping plate is provided with a pressure sensor. The top of the lower clamping rod is provided with a lower clamping plate, and the clamping surface of the lower clamping plate is provided with a ring-shaped positioning mark. The upper clamping plate, the lower clamping plate and the rotating threaded rod are coaxially arranged. The outer side wall of the upper clamping rod is provided with a sliding block and a longitudinal flat key, the inner wall of the driving rod is correspondingly provided with a sliding groove and a key groove, and the flat key is matched with the key groove to realize the circumferential linkage of the driving rod and the upper clamping rod. ​ ​ ​ ​ ​ 2. A flexible feed low-damage core diameter setting and polishing device according to claim 1, characterized in that, ​ 3. A flexible feed low-damage core diameter setting and polishing apparatus according to claim 2, characterized in that, ​ ​ ​ ​ 4. A flexible feed low-damage core diameter setting and polishing apparatus according to claim 1, characterized in that, The diameter limiting control module comprises: A precision scale is horizontally fixed to the rear side of the support, and two precision scales are symmetrically distributed between the sliding table and the fixed table along the sliding direction of the sliding table; A contact type electric control limiter is detachably assembled on the precision scale at any position, the triggering end of the contact type electric control limiter is aligned with the side surface of the sliding table, the signal output end is electrically connected with the gas path electromagnetic valve through a control line, and the electromagnetic valve is connected in series in the high-pressure gas pipeline between the air pump and the air cylinder.

5. A flexible feed low-damage core diameter setting and polishing apparatus according to claim 1, characterized in that, A piezoelectric ceramic actuator is arranged between the four corners of the base and the fixed rod, and is used to drive the core to realize micro-amplitude reciprocating swing of-5°-5° around the center axis of the core.

6. A flexible feed low-damage core diameter setting and polishing apparatus according to claim 2, characterized in that, The water cooling module comprises: A water tank is arranged outside the outer shell and carries a submersible pump inside; A sprayer is arranged inside the outer shell and faces the polishing area and is in communication with the submersible pump through a water pipe.

7. A flexible feed low-damage core diameter setting and polishing apparatus according to claim 2, characterized in that, The safety protection module comprises: An emergency stop button is a normally closed contact and is electrically connected with the power supply control end of each module; LED status indicator lights are red / green / yellow three colors, corresponding to fault / emergency stop, standby / normal operation, polishing / movement adjustment working condition; A start pedal and a reset pedal are connected in series in the start circuit of the power source of the core rotation driving module and the power source of the pneumatic flexible feeding module by using interlocking control logic; the start pedal is used to start the cooperative polishing process of the core rotation and pneumatic feeding; and the reset pedal is used to stop the current process and control the pneumatic flexible feeding module to retreat to the initial position.

8. A method of polishing based on the flexible feed low-damage core diameter straightening and polishing device according to any one of claims 1-7, characterized in that, The method comprises the following steps: S1. Equipment pre-inspection and parameter pre-setting: S1.

1. Turn on the device power supply, confirm that the electrical system is normal through the green light of the LED status indicator light, start the air pump, adjust the air pressure to the preset working pressure, and check that there is no leakage in the gas path; S1.

2. According to the lithology of the core, select the corresponding grit size of the diamond sand plate, detachably connect the diamond sand plate and the connecting rod at the bottom of the sliding table, and ensure that the arc-shaped working surface of the diamond sand plate faces the core side; S2. Core clamping and centering calibration: S2.

1. Rotate the butterfly nut counterclockwise until the butterfly nut is completely separated from the non-slip washer, open the splash baffle, and rotate the handle driving the upper clamping rod counterclockwise to move upward, so that the distance between the upper clamping plate and the lower clamping plate is greater than the length of the core; S2.

2. Place the core on the clamping surface of the lower clamping plate, adjust the position of the core through the annular positioning mark in the center of the lower clamping plate, so that the center of the core coincides with the center of the mark, and the preliminary centering is completed; S2.

3. Rotate the handle counterclockwise to drive the upper clamping plate downward, until the pressure sensor at the bottom of the upper clamping plate detects that the clamping force reaches the preset range of 5 N-10 N, stop rotating the handle and lock the butterfly nut, and close the splash baffle of the outer shell; S3. Flexible polishing and diameter control: S3.

1. According to the target diameter of the core to be polished, set the position of the contact type electric control limiter on the precision scale, and preset the maximum inner feeding distance of the sliding table; S3.

2. Press the start pedal of the safety protection module to simultaneously start the drive motor of the core rotation drive module, the submersible pump of the water cooling module and the cylinder of the pneumatic flexible feed module. At this time, the LED status indicator light switches from green to yellow, indicating that the equipment has entered the grinding operation state. S3.

3. The core rotates around its own central axis, the water cooling module is activated, the cylinder pushes the slide table to flexibly feed towards the core along the slide, the diamond plate arc working surface contacts the core surface and begins to grind, at the same time the piezoelectric ceramic actuator drives the core to achieve a micro-amplitude reciprocating swing of -5°~5°, and water mist spray covers the grinding area. S3.

4. When the core diameter is ground to the target value, the side of the slide table contacts and triggers the contact-type electronic limit switch. The limit switch sends a signal to the air circuit solenoid valve, the solenoid valve switches to the exhaust state, the compressed air in the cylinder is discharged, the slide table is reset under the action of the return spring, the drive motor and submersible pump stop in sequence, and the LED status indicator light switches from yellow to green, indicating that the grinding operation is completed. S4. Core unloading and equipment cleaning: S4.

1. After the equipment has completely stopped, open the splash guard, unlock the wing nut and use the crank to move the upper clamp plate up, take out the rock core and check the diameter accuracy and surface quality; S4.

2. Turn off the main power supply, clean the rock debris and accumulated water inside the casing, blow away residual particles on the slide rail and diamond plate surface, and complete the equipment maintenance.

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