A stone cultural relic repairing device and surface repairing method

Abstract

The application discloses a kind of stone cultural relics's repair equipment and surface repair method, it is related to cultural relic repair technical field, including the placing table for placing cultural relics to be repaired, still including visual scanning unit, control unit, material supply and premix unit and execution perfusion unit, material supply and premix unit are electrically connected with control unit, this unit includes bacteria liquid warehouse, cementing liquid warehouse, pH regulator warehouse, dilution buffer solution warehouse, powder slurry warehouse and a batch processing type mixing tank, above-mentioned each warehouse body is communicated with batch processing type mixing tank, for supplying repair raw material as needed.The application realizes the adaptive repair to crack morphology;Through batch, variable concentration perfusion strategy, the problem of uneven filling caused by traditional one-time perfusion is solved;Through the cooperation of elastic stirring blade in batch processing type mixing tank and self-bleeding air pressure structure, efficient switching of mixing and discharging and automatic cleaning of pipeline are realized, the accuracy and reliability of multi-batch perfusion process are ensured.

Description

Technical Field

[0001] This invention relates to the field of cultural relic restoration technology, and in particular to a restoration device and surface restoration method for stone cultural relics. Background Technology

[0002] Stone artifacts are precious carriers of human civilization, and surface cracks are a major cause of structural instability and accelerated weathering and erosion. Microbial-induced calcium carbonate precipitation (MICP) technology, as an emerging biomineralization restoration method, has become a cutting-edge research direction in this field because its restoration products are similar in composition to the original carbonate rock artifacts, are environmentally friendly, and have both penetrating reinforcement and adhesive filling capabilities.

[0003] There are two process routes for MICP technology in engineering applications: one is the "two-phase injection method," which involves injecting the bacterial solution first, and then injecting the cementing liquid after the bacterial solution adheres to the inner wall of the crack, allowing the two to meet and react inside the crack; the other is the "one-phase mixing method," which involves pre-mixing the bacterial solution and cementing liquid and then injecting them all at once. Although the two-phase injection method can avoid premature reactions during the grouting process, it is complex to operate, requiring precise control of the time interval and injection sequence between the two injections. Furthermore, the bacterial solution is prone to loss due to gravity or uneven distribution after the first injection, leading to uneven subsequent reactions. In contrast, the one-phase mixing method has become the mainstream choice for on-site repair due to its simple operation and ease of engineering implementation.

[0004] To address the problem of immediate reaction between bacterial solution and cementitious liquid in single-phase mixing methods, leading to localized solidification of the slurry before full penetration, existing technologies propose adjusting the initial pH of the mixed slurry to the acidic range (e.g., 4.5-6.0) by adding a pH adjuster. This temporarily inhibits bacterial urease activity, delays calcium carbonate formation, and provides a time window for slurry penetration. This low-pH inhibition technology is well-known to those skilled in the art and has been applied in laboratory research and some engineering practices.

[0005] Currently, on-site repair mainly relies on manual labor or semi-automatic equipment. Operators usually rely on experience to pre-mix a fixed ratio of bacterial solution and cementing solution (i.e., "one-phase method" slurry), and then use a handheld injection device to inject it. The cracks are formed by extending from the surface opening to the inside, and there are a large number of radial microcracks at the bottom. The traditional handheld injection method of filling in one go is very easy to generate calcium carbonate crystals quickly in the shallow area of ​​the crack, causing the slurry to solidify locally before it can fully diffuse into the deep part of the crack, and finally forming a non-uniform structure of "material accumulation and hardening near the opening and void filling in the internal area".

[0006] Therefore, the grout needs to fill a large space in the crack cavity, but the microcrack area at the bottom needs to be preferentially penetrated and anchored by low-concentration grout, while the wide cavity in the middle and upper part needs to be filled with sufficient material by subsequent grout to form structural strength. If a fixed formula grout is used for one-time injection, it is impossible to simultaneously meet the dual requirements of "preferential penetration and anchoring of microcrack areas" and "effective filling and reinforcement of wide cavities". Even if the time window is gained by low pH inhibition, it is difficult to avoid non-uniform repair results with insufficient filling of microcracks at the bottom and sparse material in the upper cavity. Summary of the Invention

[0007] The purpose of this invention is to solve the problem that existing technologies cannot simultaneously achieve the goals of penetrating and anchoring microcracks and effectively filling large cavities, and to propose a restoration device and surface restoration method for stone cultural relics.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A restoration device and surface restoration method for stone cultural relics, including a platform for placing the cultural relic to be restored, and further comprising: A visual scanning unit is used to acquire images or point cloud data of the cracks to be repaired. The control unit, which is communicatively connected to the visual scanning unit, is used to process the data to generate control instructions that include a three-dimensional model of the crack and a repair plan. The material supply and premixing unit is electrically connected to the control unit. The material supply and premixing unit includes a bacterial liquid tank, a cementing liquid tank, a pH adjuster tank, a dilution buffer tank, a powder slurry tank, and a batch mixing tank. The bacterial liquid tank, cementing liquid tank, pH adjuster tank, dilution buffer tank, and powder slurry tank are all connected to the batch mixing tank. An execution infusion unit is electrically connected to the control unit. The execution infusion unit includes a multi-axis motion platform, and the batch mixing tank is fixed on the moving parts of the multi-axis motion platform. A bracket is installed at the bottom of the batch mixing tank, and an infuser and the vision scanning unit are fixedly installed on the bracket. The output hole at the bottom of the batch mixing tank is connected to the infuser through a conduit.

[0009] Preferably, the batch mixing tank has an open top and a piston disc that is slidably installed inside, forming a sealed chamber inside the batch mixing tank; the piston disc is provided with multiple feed inlets, and each feed inlet is connected to the bacterial liquid tank, the cementing liquid tank, the pH adjuster tank, the dilution buffer tank and the powder slurry tank respectively through a pipe equipped with a metering pump.

[0010] Preferably, a servo motor is installed at the bottom of the batch mixing tank, and the output end of the servo motor passes through the batch mixing tank and is equipped with a stirring shaft; an inner sleeve is provided in the middle of the piston plate, and the stirring shaft is sealed and movably connected to the inner sleeve; an axial groove is opened on the outer wall of the stirring shaft, and an elastic stirring blade with its bottom end bent outward is installed at the upper end of the groove, and the elastic stirring blade is adapted to the groove.

[0011] Preferably, an electric push rod is installed above the batch mixing tank to drive the piston disc to move axially along the batch mixing tank; when the electric push rod drives the piston disc to move downward, the inner sleeve compresses the elastic stirring blade to retract into the slot; when the piston disc returns to its original position, the elastic stirring blade pops outward under its own elastic force to form stirring blades.

[0012] Preferably, a retaining ring is installed on the upper part of the piston disc, and an outer sleeve is slidably and sealingly provided on the inner sleeve; the telescopic end of the electric push rod is fixedly connected to the outer sleeve; a sealing plate is installed at the bottom end of the outer sleeve, which slides and seals against the inner wall of the retaining ring, forming a pressure chamber between the retaining ring and the sealing plate; a one-way air inlet valve is provided on the sealing plate, and a one-way exhaust valve communicating with the pressure chamber is provided at the bottom of the piston disc, the one-way exhaust valve corresponding to the output hole at the bottom of the batch mixing tank; a spring is provided between the sealing plate and the piston disc.

[0013] Preferably, the control unit is configured to: compare the opening width of the crack three-dimensional model with a preset crack opening width threshold, thereby automatically selecting one of two repair modes; the repair modes include a first mode and a second mode; the preset crack opening width threshold is 0.5mm.

[0014] Preferably, the control unit is further configured to: calculate and output the flow parameters of each metering pump for the selected repair mode to prepare the target slurry, and at the same time generate the movement trajectory command of the multi-axis motion platform and the injection flow command associated with the position of each point on the movement trajectory in real time.

[0015] A method for surface restoration of stone artifacts includes the following steps: Step 1, Scanning and Modeling: Crack information is acquired using the vision scanning unit fixed on the support, and a three-dimensional model of the crack is constructed by the control unit; Step 2, Decision Planning: The control unit analyzes the three-dimensional model, selects the repair mode based on the crack opening width, and generates a repair plan including slurry formulation, movement path, and synchronous flow planning. Step 3, slurry preparation: According to the slurry formula in the repair scheme, control each metering pump to pump a preset amount of bacterial solution, cementing solution, pH adjuster, dilution buffer and powder slurry into the sealed chamber of the batch mixing tank, start the servo motor to drive the stirring shaft to rotate, so that the elastic stirring plate stirs the mixture to form an inhibitory slurry with an initial pH value adjusted to between 4.5 and 6.0; Step 4, Intelligent Infusion in Batches: S1, Positioning and Injection: Drive the multi-axis motion platform to make the injector move at a constant speed from the crack start position to the end position, drive the electric push rod to make the piston disc move downward, and squeeze the current batch of slurry in the sealed chamber out of the injector through the output hole and the conduit. S2, Quantitative control: The control unit controls the advance stroke of the electric push rod according to the planned injection volume of the current batch, so that the volume of slurry pushed out in a single operation is equal to the planned injection volume of the batch. S3, Intermittent venting: After the current batch of injection is completed, the electric push rod is driven to continue to move down, and the gas in the air pressure chamber is used to discharge the residual slurry in the conduit and injection device into the crack or waste liquid area to complete the pipeline cleaning; S4, Reaction Waiting: Suspend equipment operation and wait for 5-12 hours for the microbial induction reaction time; S5, Judgment and Cycle: Determine whether all planned batches have been completed. If not, dynamically allocate the next batch of slurry to the sealed chamber according to the repair plan, and repeat steps S1 to S4 until all batches are completed. Step 5, Final Cleaning: After the last batch of slurry is injected and drained, the equipment is cleaned for the final cleaning.

[0016] Preferably, in step two, when the crack opening width is less than 0.5 mm, the first mode is selected; when the crack opening width is greater than or equal to 0.5 mm, the second mode is selected; in the first mode, no powder slurry is added to the slurry; in the second mode, powder slurry is added to the slurry according to a preset ratio.

[0017] Preferably, in step four, during the batch-based quantitative injection, the bacterial concentration of each batch of slurry is set to increase in a stepwise manner, with the bacterial concentration of the later batch being higher than that of the previous batch; the number of injection batches is determined based on the total volume of the crack and the effective diffusion range of a single injection, preferably 2-4 batches.

[0018] Compared with the prior art, the present invention has the following advantages: This invention uses a visual scanning unit to accurately acquire a three-dimensional model of the crack. The control unit automatically selects the repair mode based on the crack opening width and a preset crack opening width threshold (0.5mm). Although existing low-pH inhibition technology provides the grout with time to penetrate, it cannot address the varying grout properties required for cracks of different widths if only a fixed-formula grout is injected in a single application. This invention ensures that different cracks can receive a suitable injection strategy through intelligent selection of two modes. By injecting in batches with varying concentrations, the time window gained by low-pH inhibition is transformed into an orderly and controllable layer-by-layer filling process. Powder reinforcement provides a true physical enhancement mechanism for wide cracks. The synergistic effect of these three factors enables the single-phase mixing method to achieve high-quality repair of complex cracks while maintaining its ease of operation, providing a reliable technical solution for the engineering application of MICP technology in the field of cultural relic protection.

[0019] This invention is based on the latest research results on the MICP reaction mechanism and adopts a control strategy of gradually increasing bacterial solution concentration while keeping the cementing solution concentration constant. The cementing solution concentration is stably controlled within the optimal range of 0.5-0.75 mol / L to ensure that calcium carbonate precipitation occurs in a stable chemical environment, avoiding the formation of metastable crystals induced by excessive concentration, while ensuring a stable supply of raw materials. The bacterial solution concentration is gradually increased. The first batch uses a low bacterial solution concentration (OD600≈0.3-0.5), taking advantage of the higher urease activity of low-density bacteria to preferentially penetrate into the radial microcrack area at the bottom of the V-shaped crack, forming a uniformly dispersed crystal nucleus layer on the inner wall of the microcrack, achieving preferential anchoring of the weakest area. Subsequent batches gradually increase the bacterial solution concentration (OD600 gradually increases to 1.0), adding reaction sites on the existing crystal nucleus framework, guiding the orderly growth of calcium carbonate crystals, and finally forming a uniform and dense overall repair structure from microcracks to macrocracks.

[0020] For cracks with a width greater than or equal to the crack opening width threshold (second mode), this invention introduces a powder-reinforcing grout in subsequent injection batches. The cementing liquid chamber stores mineral powder compatible with the stone artifact material (such as the same type of stone powder), which is added in a preset proportion in the batches injecting the wide cavity. The powder particles accumulate in the wide cavity of the crack to form a physical skeleton. The subsequently generated calcium carbonate crystals cement the powder particles together to form a "calcium carbonate-powder composite material". The powder particles occupy the volume, which greatly reduces the shrinkage after pure MIP curing. At the same time, the strength of the powder skeleton cemented by calcium carbonate is significantly higher than that of pure MIP restorations. In addition, the powder can be stone powder consistent with the artifact itself, realizing true "stone to stone", perfectly meeting the material compatibility principle of cultural relic protection.

[0021] The batch mixing tank designed in this invention adopts a combination structure of piston disc and elastic stirring blade. When the piston disc is in a high position, the elastic stirring blade pops outward under its own elastic force to form stirring blades. The servo motor drives the stirring shaft to rotate, which efficiently and uniformly mixes the multi-component materials in the sealed chamber, ensuring the proportioning accuracy of each batch of slurry. When the electric push rod drives the piston disc to move downward, the inner sleeve compresses the elastic stirring blade, causing it to retract completely into the slot, restoring the outer wall of the stirring shaft to a smooth state, ensuring the sealing between the piston disc and the tank wall, and preventing slurry leakage from the stirring shaft during the filling process. The mixing and filling functions are integrated into the same chamber, eliminating the need for separate mixing tanks and filling cylinders, avoiding loss and contamination during material transfer, and greatly simplifying the equipment structure and improving reliability.

[0022] This invention features a pneumatic chamber on the upper part of the piston disc, consisting of a retaining ring, an outer sleeve, a sealing plate, and a spring. It also includes a one-way air inlet valve and a one-way air outlet valve. This structure ensures that there is no residue in the pipeline after each injection, preventing cross-contamination between the previous batch of slurry and the next batch of mixed liquid. This guarantees the accuracy of the slurry ratio for each batch in the variable concentration batch injection process, and is the fundamental guarantee for achieving batch-by-batch incremental control of bacterial concentration. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a stone artifact restoration device proposed in this invention; Figure 2 A schematic diagram of the crack to adapt to the first mode; Figure 3 A schematic diagram of the crack to adapt to the second mode; Figure 4 This is a schematic diagram of the batch mixing tank in a stone artifact restoration device proposed in this invention; Figure 5 This is a schematic diagram of the piston disc structure in a stone artifact restoration device proposed in this invention; Figure 6 This is a schematic diagram of the stirring shaft in a stone artifact restoration device proposed in this invention; Figure 7 This is a schematic diagram of the initial state of the piston disc in a stone artifact restoration device proposed in this invention; Figure 8 This is a schematic diagram of the piston disc in the downward pressing state in a stone artifact restoration device proposed in this invention; Figure 9 for Figure 7 A magnified structural diagram of part A in the middle.

[0024] In the diagram: 1. Vision scanning unit; 2. Control unit; 3. Material supply and premixing unit; 31. Bacterial liquid tank; 32. Cementing liquid tank; 33. pH adjuster tank; 34. Dilution buffer tank; 35. Powder slurry tank; 36. Batch processing mixing tank; 361. Piston disc; 362. Sealed chamber; 363. Feed inlet; 364. Servo motor; 365. Stirring shaft; 366. Inner sleeve; 367. Groove; 368. Elastic stirring blade; 369. Electric push rod; 3611. Snap ring; 3612. Outer tube; 3613. Sealing plate; 3614. Air pressure chamber; 3615. One-way air inlet valve; 3616. One-way exhaust valve; 3617. Output port; 3618. Spring; 4. Actuation filling unit; 41. Multi-axis motion platform; 42. Filler; 43. Support; 44. Conduit. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0026] Traditional techniques for repairing cracks in stone artifacts, especially in the application of microbial induced calcium carbonate precipitation (MICP), mainly rely on manual or semi-automatic equipment for injecting premixed slurry. Due to its reaction kinetics, this "one-phase" slurry tends to solidify prematurely in the shallow area of ​​the crack, resulting in uneven filling inside the restoration. This leads to structural defects such as "material accumulation and hardening near the crack and hollow filling in the internal area," which seriously affects the overall strength and durability of the restoration and makes it difficult to meet the high standards required for long-term preservation of cultural relics.

[0027] This invention relates to a stone artifact restoration device and method based on microbial induced calcium carbonate precipitation (MICP) technology. In order to overcome the problems of uneven filling of cracks and shallow solidification blocking deep penetration caused by one-time injection in the prior art, this invention constructs a closed-loop system integrating visual perception, intelligent decision-making, precise material preparation and cyclic injection. The specific embodiments of this invention are described in detail below with reference to the accompanying drawings.

[0028] Reference Figure 1-3 This application proposes a restoration device for stone cultural relics, including a visual scanning unit 1, a control unit 2, a material supply and premixing unit 3, and an execution pouring unit 4.

[0029] The visual scanning unit 1 is fixedly mounted on the bracket 43 of the injection unit 4. This near-axial arrangement makes the scanning angle and the injection angle highly consistent, eliminating the positional deviation between the visual guide and the execution mechanism. The visual scanning unit 1 adopts a high-precision structured light 3D scanner or laser structured light industrial camera in the existing technology. Its function is to collect the geometric information of the surface of the crack to be repaired. In actual operation, the visual scanning unit 1 emits a grating or laser line to the crack surface, and calculates the opening width, depth, direction and internal three-dimensional point cloud data of the crack by receiving the reflected light deformation. These raw data are transmitted to the control unit 2 in real time through the communication link.

[0030] The control unit 2 uses an industrial-grade PLC or high-performance industrial control computer from existing technologies. Its internal storage contains crack 3D reconstruction algorithms and repair decision models programmed by technicians in this field. After receiving point cloud data, the control unit 2 first performs noise reduction and registration processing to construct a digital 3D model of the crack. The control unit 2 is configured to execute a pattern recognition algorithm based on geometric features: the system presets a crack opening width threshold of 0.5mm. The control unit 2 automatically extracts the cross-sectional dimensions at the crack opening and compares them with the 0.5mm threshold. If the opening width is less than 0.5mm, it is determined to be a "micro crack" and the first repair mode is selected; if the opening width is greater than or equal to 0.5mm, it is determined to be a "wide crack" and the second repair mode is selected. This ensures that the subsequent injection strategy is highly adapted to the crack morphology. In addition, the control unit 2 is also responsible for generating the movement trajectory instructions of the multi-axis motion platform 41 and calculating and outputting the injection flow instructions associated with the position in real time according to the cross-sectional area change of the crack model to achieve precise material supply.

[0031] Reference Figure 1-5 The material supply and premixing unit 3 includes a bacterial liquid tank 31, a binder liquid tank 32, a pH adjuster tank 33, a dilution buffer tank 34, a powder slurry tank 35, and a batch mixing tank 36.

[0032] The bacterial culture chamber 31 contains a culture of expanded Bacillus pasteurellium, the cementing solution chamber 32 contains a mixed solution of urea and calcium source (such as calcium chloride), the pH adjuster chamber 33 is used to store dilute hydrochloric acid or citric acid to adjust the acidity, the dilution buffer chamber 34 is used to maintain ionic strength, and the powder slurry chamber 35 stores mineral micro powders (such as calcite powder or quartz powder) that are compatible with the material of the cultural relic. All of the above chambers are connected to the batch mixing tank 36 through pipelines with metering pumps to ensure that the chemical ratio of each batch of slurry strictly meets the design value.

[0033] Reference Figure 5-9The batch mixing tank 36 adopts a cylindrical structure with an open top. Inside, there is an axially sliding piston disc 361. The outer edge of the piston disc 361 is embedded with a corrosion-resistant sealing ring (such as polytetrafluoroethylene material), which fits tightly against the inner wall of the batch mixing tank 36, thereby forming a sealed chamber 362 at the bottom inside the batch mixing tank 36. The piston disc 361 has multiple feed ports 363. Each feed port 363 is connected to the connecting pipes of the bacterial liquid chamber 31, the cementing liquid chamber 32, the pH adjuster chamber 33, the dilution buffer chamber 34, and the powder slurry chamber 35 through an independent pipe, so that the material can be directly pumped into the sealed chamber 362.

[0034] Reference Figure 2-9 To resolve the conflict between mixing and sealing, a servo motor 364 is installed at the center of the bottom of the batch mixing tank 36. The output shaft of the servo motor 364 passes through the bottom of the tank and is connected to the stirring shaft 365. The stirring shaft 365 extends upward into the sealed chamber 362 and passes through the inner sleeve 366 at the center of the piston disc 361. The inner sleeve 366 and the stirring shaft 365 are connected by a mechanical seal to ensure that the liquid in the sealed chamber 362 does not leak along the shaft.

[0035] The outer wall of the stirring shaft 365 is provided with a groove 367 along the axial direction. The groove 367 is preferably dovetail-shaped. An elastic stirring blade 368 is fixedly installed at the top of the groove 367. The bottom end of the elastic stirring blade 368 is bent outward. In its natural state (piston disc 361 is in a high position), the elastic stirring blade 368 pops outward under its own elastic force to form stirring blades and increase the stirring radius. When the servo motor 364 is started, the stirring shaft 365 rotates at high speed. The popped-out elastic stirring blade 368 performs intense shearing and stirring on the material in the sealed chamber 362 to ensure that the bacterial liquid, cementing liquid, buffer solution and powder slurry are uniformly mixed in a short time to form an inhibitory slurry with an initial pH value between 4.5 and 6.0.

[0036] When grouting is required, the electric push rod 369 installed above the batch mixing tank 36 is activated, driving the piston disc 361 to move downward. During this process, the inner sleeve 366 fixed on the piston disc 361 moves downward as well. The lower edge of the inner sleeve 366 contacts and compresses the elastic stirring blade 368, causing it to retract into the slot 367. At this time, the outer wall of the stirring shaft 365 returns to a smooth cylindrical shape, and the piston disc 361 can slide downward without obstruction. Moreover, the sealing between the stirring shaft 365 and the piston disc 361 is not affected by the stirring blade, effectively preventing the slurry from leaking from the gaps under pressure.

[0037] To achieve complete isolation between multiple injection batches and prevent cross-contamination of slurries of different concentrations or formulations in the pipeline, this invention features a retaining ring 3611 coaxially mounted on the upper part of the piston disc 361. An outer sleeve 3612 is slidably fitted around the outer sleeve 366. The telescopic end of the electric push rod 369 is fixedly connected to the outer sleeve 3612. A sealing plate 3613 is fixed to the bottom end of the outer sleeve 3612. The outer edge of the sealing plate 3613 makes sealing sliding contact with the inner wall of the retaining ring 3611, thereby ensuring proper sealing between the piston disc 3611 and the inner sleeve 3612. A closed air pressure chamber 3614 is formed between the 11 and the sealing plate 3613. A one-way air inlet valve 3615 is installed on the sealing plate 3613, which only allows external air to enter the air pressure chamber 3614. A one-way exhaust valve 3616 communicating with the air pressure chamber 3614 is opened at the bottom of the piston plate 361. The outlet of the one-way exhaust valve 3616 is directly opposite the output hole 3617 at the bottom of the batch mixing tank 36. A spring 3618 is also provided between the sealing plate 3613 and the piston plate 361 to provide a reset spring force.

[0038] Reference Figure 2-9 During normal slurry preparation and mixing, piston disc 361 is in a high position, and the air pressure chamber 3614 has a large volume, with internal air pressure balanced with atmospheric pressure. When grouting, electric push rod 369 drives piston disc 361 downwards to discharge the slurry. After this batch of slurry is discharged, if a switch to the next batch is needed, electric push rod 369 does not retract but continues to press down for a short distance. At this time, outer sleeve 3612 continues to descend with electric push rod 369, compressing spring 3618, causing the volume of air pressure chamber 3614 to decrease, and the internal air pressure... As the pressure rises, the high-pressure gas opens the one-way exhaust valve 3616 and rushes into the conduit 44 through the output hole 3617. This high-pressure airflow will thoroughly blow out the residual slurry on the inner wall of the conduit 44 and at the needle of the injector 42, and discharge it into the end of the crack or the waste liquid collection area. Subsequently, the electric push rod 369 retracts, the volume of the air pressure chamber 3614 increases to form a negative pressure, and external air is replenished through the one-way air inlet valve 3615 to prepare for the next evacuation. This air-pumped liquid self-cleaning mechanism is the physical guarantee for achieving high-precision batch-by-batch variable concentration injection.

[0039] Reference Figure 1 and Figure 7-9 The infusion unit 4 includes a multi-axis motion platform 41 and an infusion device 42. The batch mixing tank 36 is fixed on the mover of the multi-axis motion platform 41, so that the batch mixing tank 36 and the infusion device 42 can move synchronously in three dimensions. The bracket 43 is fixed to the bottom of the batch mixing tank 36 and carries both the vision scanning unit 1 and the infusion device 42, ensuring that the relative position between the scanning field of view and the infusion needle of the infusion device 42 is constant. The infusion device 42 is connected to the output hole 3617 at the bottom of the batch mixing tank 36 through a corrosion-resistant conduit 44. The multi-axis motion platform 41 drives the infusion device 42 to move at a constant speed along the crack path according to the trajectory command generated by the control unit 2.

[0040] Based on the above-mentioned equipment, the repair method of the present invention includes the following detailed steps: Step 1, Scanning and Modeling: Adjust the artifact placement platform to a suitable position, start the visual scanning unit 1, the scanning unit 1 moves along the crack surface to take pictures and obtain high-density point cloud data, the control unit 2 performs surface reconstruction on the point cloud data, and generates a three-dimensional solid model including the crack opening width, depth variation, internal cavity volume and microcrack distribution.

[0041] Step two, decision planning: The decision algorithm of control unit 2 automatically analyzes the 3D model. The system uses 0.5mm as a boundary to determine the width of the crack opening.

[0042] If the width is <0.5mm (first mode): the system determines that the crack is mainly a permeable repair, generates a repair scheme without powder slurry, and sets the bacterial concentration to a low constant value or a slowly increasing gradient.

[0043] If the width is ≥0.5mm (second mode): the system determines that the crack has a "V" shaped structure, the bottom microcracks need to be anchored first, and the upper wide cavity needs to be filled and reinforced. The system generates a repair plan that includes a powder slurry addition plan and a step-by-step increase plan for bacterial solution concentration. Specifically, the system calculates the total volume of the crack and divides the repair process into N batches (N is preferably 2-4 batches). The first batch contains only basic cementing liquid and low-concentration bacterial solution to penetrate the microcracks; the bacterial solution concentration is gradually increased in subsequent batches, and powder slurry is added in the second batch and thereafter.

[0044] Step 3, slurry preparation: Taking the first batch as an example, the control unit 2 sends instructions to each metering pump, and the bacterial liquid tank 31, the cementing liquid tank 32, the pH adjuster tank 33, and the dilution buffer tank 34 (the powder slurry tank 35 is only for subsequent batches in the second mode) are injected into the sealed chamber 362 in proportion. After the injection is completed, the servo motor 364 is started, and the stirring shaft 365 drives the pop-out elastic stirring plate 368 to rotate. The stirring time is set to 30-60 seconds to ensure that the slurry is evenly dispersed and the bacterial activity is not significantly affected. After stirring, an acidic inhibitory slurry is formed.

[0045] Step 4, Intelligent Infusion in Batches: S1, Positioning and Injection: The multi-axis motion platform 41 drives the injector 42 to move from the beginning of the crack along the crack trajectory to the end. The electric push rod 369 pushes the piston disc 361 downward. During this process, the inner sleeve 366 gradually compresses and retracts the elastic stirring plate 368. The piston disc 361 squeezes the slurry in the sealed chamber 362, causing it to be squeezed out of the injector 42 through the output hole 3617 and the conduit 44.

[0046] S2, Quantitative control: The volume of grout in each batch is calculated based on the total volume of the cracks and the number of batches, ensuring that the volume of grout delivered in a single batch is equal to the planned quantity for that batch.

[0047] S3, Intermittent venting: After the current batch of infusion is completed, the electric push rod 369 does not retract, but continues to descend a set distance. The outer tube 3612 compresses the spring 3618, and the air pressure in the air pressure chamber 3614 increases. The one-way exhaust valve 3616 is pushed open, and high-pressure gas enters the conduit 44, forming a gas-liquid two-phase flow. This completely discharges the residual slurry from the conduit 44 wall and the needle of the infusion device 42, ensuring that there is no dead volume residue in the pipeline and preventing the mixing of the low-concentration bacterial solution of the previous batch with the high-concentration bacterial solution of the next batch, as well as the sedimentation and blockage of residual slurry in the pipeline.

[0048] S4, Reaction Waiting: The equipment is suspended and left to stand for 5-12 hours. During this period, due to the initial pH of the slurry being acidic (4.5-6.0), the bacterial urease activity is inhibited, the slurry remains liquid and continues to penetrate deeper into the cracks. At the same time, low-concentration bacterial solution preferentially adheres to the bottom micro-cracks and begins to slowly metabolize.

[0049] S5, Judgment and Loop: After the waiting time ends, control unit 2 determines whether all N batches have been completed.

[0050] If not completed (for the second mode): Control unit 2 instructs the metering pump to inject the next batch of raw materials into the empty sealed chamber 362. At this time, the powder slurry hopper 35 is opened, the flow rate of the bacterial solution pump increases, and the servo motor 364 is started again for stirring. Then S1-S4 are repeated. It is worth noting that the bacterial solution concentration (OD600) of the subsequent batches is higher than that of the previous batch (for example, from 0.4 to 0.7 and then to 1.0). The addition ratio of powder slurry is also increased batch by batch. The high concentration of bacterial solution reacts rapidly on the formed crystal nucleus layer to generate a large number of calcium carbonate crystals. The powder forms a skeleton in the wide cavity, and the crystals grow and encapsulate the powder to form a high-strength composite material.

[0051] If completed, proceed to step five.

[0052] Step 5, final cleaning: After the last batch of filling and purging operations are completed, the electric push rod 369 is reset. At this time, the air pressure chamber 3614 generates negative pressure again to draw in air. Optionally, the control unit 2 controls the metering pump to pump in a small amount of cleaning fluid (such as buffer solution) and repeats the above filling and purging operations to perform a final flushing of the entire flow path, ensuring that the inside of the equipment is clean and preventing residual slurry from solidifying and clogging the pipeline.

Claims

1. A restoration device for stone cultural relics, comprising a platform for placing the cultural relic to be restored, characterized in that, Also includes: The visual scanning unit (1) is used to acquire images or point cloud data of the crack to be repaired; The control unit (2) is communicatively connected to the visual scanning unit (1) and is used to process the data to generate control instructions containing a three-dimensional model of the crack and a repair plan; The material supply and premixing unit (3) is electrically connected to the control unit (2). The material supply and premixing unit (3) includes a bacterial liquid tank (31), a cementing liquid tank (32), a pH adjuster tank (33), a dilution buffer tank (34), a powder slurry tank (35), and a batch processing mixing tank (36). The bacterial liquid tank (31), cementing liquid tank (32), pH adjuster tank (33), dilution buffer tank (34), and powder slurry tank (35) are all connected to the batch processing mixing tank (36). The execution infusion unit (4) is electrically connected to the control unit (2). The execution infusion unit (4) includes a multi-axis motion platform (41). The batch mixing tank (36) is fixed on the moving parts of the multi-axis motion platform (41). A bracket (43) is installed at the bottom of the batch mixing tank (36). An infusion device (42) and the vision scanning unit (1) are fixedly installed on the bracket (43). The output hole (3617) at the bottom of the batch mixing tank (36) is connected to the infusion device (42) through a conduit (44).

2. The restoration equipment for stone cultural relics according to claim 1, characterized in that, The batch mixing tank (36) has an opening at the top and a piston disc (361) is slidably installed inside, forming a sealed chamber (362) inside the batch mixing tank (36). The piston disc (361) is provided with multiple feed inlets (363), and each feed inlet (363) is connected to the bacterial liquid tank (31), the cementing liquid tank (32), the pH adjuster tank (33), the dilution buffer tank (34), and the powder slurry tank (35) respectively through a pipe equipped with a metering pump.

3. The restoration equipment for stone cultural relics according to claim 2, characterized in that, A servo motor (364) is installed at the bottom of the batch mixing tank (36). The output end of the servo motor (364) passes through the batch mixing tank (36) and is equipped with a stirring shaft (365). An inner sleeve (366) is provided in the middle of the piston disc (361). The stirring shaft (365) is sealed and movably connected to the inner sleeve (366). An axial groove (367) is opened on the outer wall of the stirring shaft (365). An elastic stirring plate (368) with its bottom end bent outward is installed at the upper end of the groove (367). The elastic stirring plate (368) is adapted to the groove (367).

4. The restoration equipment for stone cultural relics according to claim 3, characterized in that, An electric push rod (369) is installed above the batch mixing tank (36) to drive the piston disc (361) to move axially along the batch mixing tank (36). When the electric push rod (369) drives the piston disc (361) to move downward, the inner sleeve (366) compresses the elastic stirring blade (368) to retract it into the slot (367). When the piston disc (361) returns to its original position, the elastic stirring blade (368) pops outward under its own elastic force to form a stirring blade.

5. The restoration equipment for stone cultural relics according to claim 4, characterized in that, A retaining ring (3611) is installed on the upper part of the piston disc (361), and an outer sleeve (3612) is provided for sealing and sliding outside the inner sleeve (366). The telescopic end of the electric push rod (369) is fixedly connected to the outer sleeve (3612). A sealing plate (3613) is installed at the bottom of the outer sleeve (3612) and slides in sealing with the inner wall of the retaining ring (3611), forming a pressure chamber (3614) between the retaining ring (3611) and the sealing plate (3613). A one-way air inlet valve (3615) is provided on the sealing plate (3613), and a one-way exhaust valve (3616) communicating with the pressure chamber (3614) is provided at the bottom of the piston disc (361). The one-way exhaust valve (3616) corresponds to the output hole (3617) at the bottom of the batch mixing tank (36). A spring (3618) is provided between the sealing plate (3613) and the piston disc (361).

6. The restoration equipment for stone cultural relics according to claim 1, characterized in that, The control unit (2) is configured to: compare the opening width of the crack three-dimensional model with a preset crack opening width threshold, thereby automatically selecting one of the two repair modes; the repair modes include a first mode and a second mode; the preset crack opening width threshold is 0.5mm.

7. The restoration equipment for stone cultural relics according to claim 6, characterized in that, The control unit (2) is also configured to: calculate and output the flow parameters of each metering pump for the selected repair mode to prepare the target slurry, and at the same time generate the movement trajectory command of the multi-axis motion platform (41) and the injection flow command associated with the position of each point on the movement trajectory in real time.

8. A method for surface restoration of stone cultural relics, characterized in that, The repair device according to any one of claims 1 to 7 comprises the following steps: Step 1, scanning and modeling: The visual scanning unit (1) fixed on the bracket (43) is used to obtain crack information, and the control unit (2) constructs a three-dimensional model of the crack; Step 2, decision planning: The control unit (2) analyzes the three-dimensional model, selects the repair mode according to the opening width of the crack, and generates a repair plan including slurry formula, movement path and synchronous flow planning; Step 3, slurry preparation: According to the slurry formula in the repair scheme, control each metering pump to pump a preset amount of bacterial solution, cementing solution, pH adjuster, dilution buffer and powder slurry into the sealed chamber (362) of the batch mixing tank (36), start the servo motor (364) to drive the stirring shaft (365) to rotate, so that the elastic stirring plate (368) stirs the mixture to form an inhibitory slurry with an initial pH value adjusted to between 4.5 and 6.0; Step 4, Intelligent Infusion in Batches: S1, Positioning and Injection: Drive the multi-axis motion platform (41) to make the injector (42) move at a constant speed from the beginning position to the end position of the crack, drive the electric push rod (369) to make the piston disc (361) move downward, and squeeze the current batch of slurry in the sealed chamber (362) out of the injector (42) through the output hole (3617) and the guide tube (44); S2, quantitative control: The control unit (2) controls the advance stroke of the electric push rod (369) according to the planned injection volume of the current batch, so that the volume of slurry pushed out in one go is equal to the planned injection volume of the batch; S3, Intermittent venting: After the current batch of injection is completed, drive the electric push rod (369) to continue to move down, and use the gas in the air pressure chamber (3614) to discharge the residual slurry in the conduit (44) and the injector (42) into the crack or waste liquid area to complete the pipeline cleaning; S4, Reaction Waiting: Suspend equipment operation and wait for 5-12 hours for the microbial induction reaction time; S5, Judgment and Cycle: Determine whether all planned batches have been completed. If not, dynamically allocate the next batch of slurry to the sealed chamber (362) according to the repair plan, and repeat steps S1 to S4 until all batches are completed. Step 5, Final Cleaning: After the last batch of slurry is injected and drained, the equipment is cleaned for the final cleaning.

9. The surface restoration method for stone cultural relics according to claim 8, characterized in that, In step two, when the crack opening width is less than 0.5 mm, the first mode is selected; when the crack opening width is greater than or equal to 0.5 mm, the second mode is selected. In the first mode, no powder slurry is added to the slurry; in the second mode, powder slurry is added to the slurry according to a preset ratio.

10. The surface restoration method for stone cultural relics according to claim 8, characterized in that, In step four, during the batch-based quantitative injection, the bacterial concentration of each batch of slurry is set to increase in a stepwise manner, with the bacterial concentration of the later batch being higher than that of the previous batch. The number of injection batches is determined based on the total volume of the crack and the effective diffusion range of a single injection, preferably 2-4 batches.

Images