Automatic control method and device for particle sedimentation sample preparation

Abstract

The application provides a kind of particle sedimentation sample preparation automatic control method and device, it is related to the technical field of sample pretreatment of optical dating.The device comprises: central control unit, rotary drive unit, temperature control unit and liquid replacement unit, rotary drive unit is used to drive the rotation of sedimentation container, temperature control unit is used to obtain the real-time temperature of suspension in sedimentation container and adjust the temperature of suspension, liquid replacement unit is used to replace the liquid in sedimentation container.The method comprises: driving rotary drive unit to make sedimentation container rotate;After the rotation of sedimentation container stops, the real-time temperature is obtained, and the Stokes sedimentation time is corrected according to the real-time temperature compensation;According to the corrected Stokes sedimentation time, control liquid replacement unit to replace the liquid in sedimentation container.The application strips the wall surface adsorption particles by rotation and corrects the sedimentation time according to the real-time temperature, significantly improves the target particle recovery rate, eliminates the influence of temperature on sorting accuracy, and realizes the automation and standardization of sample preparation process.

Description

Technical Field

[0001] This invention relates to the field of sample pretreatment technology for optically stimulated luminescence dating, and in particular to an automatic control method and apparatus for particle sedimentation sample preparation. Background Technology

[0002] Optically stimulated luminescence (OSL) dating is an important technique widely used in Quaternary geology and environmental studies, active tectonics, archaeology, and paleoseismology. OSL dating typically employs two particle sizes: fine particles, usually 4-11 μm in diameter; and coarse particles, between 90-300 μm in diameter, with 90-125 μm and 150-180 μm being the most common. Fine-grained samples (4-11 μm) are crucial for dating in scenarios where coarse-grained samples are difficult to obtain, such as fluvial and lacustrine sediments, fault gouge, and archaeological sites. Currently, laboratories commonly use a wet sedimentation technique for separating and preparing samples of this particle size: a sample suspension containing multiple particle sizes is injected into a beaker or graduated cylinder, allowed to stand for a specific time according to Stokes' law, the supernatant is removed by siphoning or pouring, and finally, the concentrated bottom liquid is transferred to a dating disc and dried.

[0003] However, in existing technologies, fine particles tend to form aggregates during settling, causing their actual settling velocity to deviate from Stokes' law. This reduces the separation accuracy between different particle sizes. The entire settling and siphoning process relies entirely on the operator's manual operation and subjective experience, resulting in poor consistency between batches and introducing human error that is difficult to quantify. Therefore, there is an urgent need for an automated, high-precision particle settling sample preparation scheme. Summary of the Invention

[0004] This invention provides an automatic control method and apparatus for particle sedimentation sample preparation to solve the problems of low automation and sedimentation accuracy in existing technologies.

[0005] In a first aspect, embodiments of the present invention provide an automatic control method for particle sedimentation sample preparation. The automatic control device for particle sedimentation sample preparation includes: a central control unit, a rotation drive unit, a temperature control unit, and a liquid replacement unit. The rotation drive unit is used to drive the sedimentation container to rotate. The temperature control unit is used to acquire the real-time temperature of the suspension in the sedimentation container and adjust the temperature of the suspension. The liquid replacement unit is used to replace the liquid in the sedimentation container. The method includes: driving the rotary drive unit to rotate the settling container; after the settling container stops rotating, acquiring the real-time temperature, and compensating and correcting the Stokes settling time based on the real-time temperature; and controlling the liquid replacement unit to replace the liquid in the settling container based on the corrected Stokes settling time. This not only solves the core problems of fine particle adsorption loss and temperature affecting sorting accuracy, but also achieves automated control of the sample preparation process, eliminating human interference.

[0006] Among these methods, by driving the container to rotate before settling, the liquid shear stress is used to detach the particles adsorbed on the wall and allow them to enter the suspension, thus solving the problem of severe adsorption loss of fine particles; by correcting the settling time according to the real-time temperature, the interference of ambient temperature fluctuations on the sorting accuracy is eliminated, thus solving the problem that the sorting accuracy is greatly affected by temperature.

[0007] In one possible implementation, the central control unit drives the rotary drive unit to rotate the settling container at a preset speed, and after a preset time, controls the rotary drive unit to stop rotating.

[0008] In one possible implementation, the preset rotational speed ranges from 0.5 to 5 rpm.

[0009] In one possible implementation, the sedimentation sample preparation device further includes an ultrasonic dispersion unit, and the central control unit is connected to the ultrasonic dispersion unit; while driving the rotary drive unit, the central control unit also controls the ultrasonic dispersion unit to apply ultrasonic energy to the suspension in an intermittent mode.

[0010] In one possible implementation, the ultrasonic energy is applied at a frequency of 40 to 80 kHz, with each application lasting 30 to 60 seconds and an interval of 2 minutes.

[0011] In one possible implementation, the central control unit compensates for and corrects the Stokes settling time based on the relationship between fluid viscosity and temperature.

[0012] In one possible implementation, the Stokes settling time is calculated based on Stokes' law, and the central control unit determines the Stokes settling time based on the diameter of the target particle, the density difference between the target particle and the suspension, the settling height, and the gravitational acceleration.

[0013] In one possible implementation, the central control unit calculates the corrected Stokes settling time based on the Stokes settling time at a preset reference temperature and the ratio of the fluid viscosity at the real-time temperature to the fluid viscosity at the reference temperature.

[0014] In one possible implementation, the central control unit calculates the fluid viscosity at the real-time temperature by linear interpolation, the linear interpolation being based on a pre-stored table of the correspondence between temperature and fluid viscosity.

[0015] In one possible implementation, the reference temperature is a standard temperature, and the central control unit calculates a standard settling time based on Stokes' law at the standard temperature, wherein the standard settling time is the Stokes settling time at the standard temperature.

[0016] In one possible implementation, the central control unit controls the liquid replacement unit to draw in the supernatant via siphoning, and then discharges the concentrated target particle suspension via bottom discharge to collect the target particles.

[0017] In one possible implementation, the central control unit sets the siphon position at a height of 80% to 90% below the liquid surface and controls the aspiration of the supernatant at a constant rate, which ensures that the target particles are not resuspended.

[0018] In a second aspect, embodiments of the present invention provide an automatic control device for fine particle sedimentation sample preparation, comprising: a sedimentation container; a rotation drive unit connected to the sedimentation container for driving the sedimentation container to rotate; a temperature control unit for acquiring the real-time temperature of the suspension in the sedimentation container and adjusting the temperature of the suspension; a liquid replacement unit for replacing the liquid in the sedimentation container; and a central control unit connected to the rotation drive unit, the temperature control unit, and the liquid replacement unit respectively, for executing the method described in the first aspect or any embodiment of the first aspect.

[0019] The above scheme achieves automation and standardization of the sedimentation sample preparation process through the collaborative work of each unit, significantly improving sample preparation efficiency and consistency.

[0020] The embodiments of the present invention have the following beneficial effects: First, it significantly improves the recovery rate of target particles. Through the synergistic effect of rotation and ultrasound, the liquid shear stress generated by rotation keeps the particles away from the wall, while the ultrasonic cavitation effect breaks up the aggregates and allows the particles adsorbed on the wall to re-enter the suspension. This combined mechanism effectively solves the problem of severe adsorption loss of fine particles.

[0021] Second, it eliminates the influence of temperature and improves sorting accuracy. By introducing real-time temperature monitoring and compensation, the settling time is accurately corrected based on the relationship between fluid viscosity and temperature, eliminating the interference of laboratory ambient temperature fluctuations on the Stokes settling formula calculation results, and ensuring that the target particle size can be accurately extracted in each sample preparation.

[0022] Third, the sample preparation process is standardized and automated. All steps are coordinated by the central control unit, enabling "one-click" operation, eliminating differences in human experience, and significantly improving the repeatability of sample preparation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an automatic control device for particle sedimentation sample preparation provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the implementation of an automatic control method for particle sedimentation sample preparation according to an embodiment of the present invention. Among them, 1-sedimentation container, 2-rotation drive unit, 3-temperature control unit, 4-liquid replacement unit, 5-ultrasonic dispersion unit, 41-siphon assembly, and 42-discharge valve. Detailed Implementation

[0024] The foregoing section introduced the commonly used "wet sedimentation" technique in laboratories for particle separation and sample preparation. However, in practice, the existing "wet sedimentation" technique has the following drawbacks: First, particle adsorption losses are significant. Fine particles (especially those smaller than 10 μm) have a large specific surface area and are easily adsorbed onto the inner wall and bottom edges of glass beakers due to electrostatic and van der Waals forces. According to literature reports, the recovery rate of target particles in traditional manual sedimentation processes is usually only 50%-70%, resulting in the waste of a large number of valuable samples (especially archaeological samples).

[0025] Second, particle agglomeration is a prominent issue. Fine particles tend to form aggregates during settling, causing the actual settling velocity to deviate from Stokes' law. This reduces the separation accuracy between different particle sizes and ultimately affects the reliability of the dating results.

[0026] Third, the effects of temperature are not compensated. The dynamic viscosity of water changes significantly with temperature, with a viscosity change of about 11% between 20°C and 25°C. However, existing technologies do not consider the effect of temperature on settling time, resulting in sorting accuracy being greatly affected by fluctuations in ambient temperature.

[0027] Fourth, it has poor repeatability and relies heavily on human experience. The entire sedimentation and siphoning process depends entirely on the manual operation and subjective experience of the experimenter. The consistency of sample preparation between different batches is poor, and the introduced human error is difficult to quantify.

[0028] Fifth, the level of automation is low. Existing methods cannot achieve automated and standardized continuous sample preparation, making it difficult to meet the needs of modern high-throughput laboratories.

[0029] In existing technologies, the patent CN107631920B disclosed by Wang Shoutong et al. uses the principle of cyclone separation, which belongs to centrifugal sedimentation rather than gravity sedimentation. Its ultrasound is used in the initial selection stage rather than the sedimentation stage, and there is no temperature compensation. Ba Huibin's master's thesis, "Separation of Microparticles Based on Ultrasonic Rotation Drive," uses the principle of ultrasonic rotation drive, which belongs to dry separation, targeting coarse particles with a particle size of 250-330μm, which is fundamentally different from the wet sedimentation of fine particles (4-11μm) in this scheme. While the Desliming Machine from VU University Amsterdam uses gravity sedimentation and automated control, it lacks core features such as container rotation, ultrasonic dispersion, and temperature compensation. None of the above-mentioned existing technologies have solved the three major technical challenges in wet sedimentation of fine particles: adsorption loss, agglomeration, and the influence of temperature.

[0030] The present invention aims to solve the technical problems existing in the prior art, such as severe adsorption loss, easy agglomeration, uncompensated temperature effects, and poor repeatability of particles (especially fine particles of 4-11μm) during sedimentation sample preparation. It provides a sedimentation sample preparation device and method that can significantly improve the recovery rate of target particles, improve dispersibility, eliminate temperature effects, and achieve automation and standardization.

[0031] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1 As shown, this embodiment provides an automatic control device for fine particle sedimentation sample preparation. The device includes: a sedimentation container 1, a rotary drive unit 2, a temperature control unit 3, a liquid replacement unit 4, and a central control unit (…). Figure 1 (Not shown in the image).

[0033] Settling container 1 is used to hold suspensions containing fine particles. Specifically, settling container 1 is made of stainless steel or glass, and its inner wall is coated with a hydrophobic and oleophobic coating, such as polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene copolymer (FEP), to reduce particle adhesion to the wall surface. The bottom of settling container 1 is designed with a conical structure, with a cone angle ranging from 60° to 90°. This design allows the settled target particles to concentrate at the lowest point of the container, facilitating subsequent collection.

[0034] The rotary drive unit 2 is connected to the settling container 1 and is used to drive the settling container 1 to rotate. Specifically, the rotary drive unit 2 includes a stepper motor (or servo motor) and its driver, as well as a reduction mechanism and a transmission shaft. The output shaft of the drive motor is connected to a rotating platform, and the settling container 1 is fixed on the rotating platform. The drive motor drives the rotating platform and causes the settling container 1 to rotate around its central axis. The rotary drive unit 2 can also be equipped with an encoder for real-time feedback of rotational speed information, forming a closed-loop control. Figure 1 In the example, the rotary drive unit 2 is positioned below the settling container 1, directly driving the container to rotate via a drive shaft. It should be understood that the rotary drive unit 2 can also employ other methods such as magnetic drive or belt drive, as long as it can achieve low-speed rotation of the settling container 1 (e.g., 0.5 to 5 rpm). By configuring the rotary drive unit 2, the settling container is rotated, and the resulting liquid shear force causes particles adsorbed on the wall to detach and enter the suspension, thereby improving the recovery rate of the target particles.

[0035] The temperature control unit 3 is used to acquire the real-time temperature of the suspension in the settling container 1 and adjust the temperature of the suspension.

[0036] Specifically, the temperature control unit 3 includes a temperature sensor and a temperature regulating element. The temperature sensor can be a PT100 platinum resistance thermometer, a thermocouple, or a digital temperature sensor (such as a DS18B20), with its probe extending into the sedimentation container 1 or closely attached to the outer wall of the container, for real-time monitoring of the suspension temperature. The temperature regulating element can be a semiconductor cooling / heating element (Peltier), a heating resistance wire, or a cooling coil, for heating or cooling the suspension as needed, regulating the suspension temperature to maintain stability. Figure 1 In the example, the temperature regulating element is wrapped around the outer wall of the settling container 1, sensing and regulating the temperature of the suspension through heat conduction. The temperature regulating element is evenly distributed circumferentially on the outer wall of the settling container 1 to ensure uniform heating. The temperature control unit 3 transmits the collected real-time temperature data to the central control unit, providing a data basis for subsequent temperature compensation and correction.

[0037] The liquid replacement unit 4 is used to replace the liquid in the settling container 1. Specifically, the liquid replacement unit 4 includes a siphon assembly 41 and a discharge valve 42 (an enlarged schematic diagram of the discharge valve is shown in Figure 1). Figure 1(Partial enlarged schematic diagram on the right side). The siphon assembly 41 is located at the upper part of the settling container 1 and includes a siphon tube, a drive motor (such as a precision lead screw motor), and a peristaltic pump. The drive motor drives the siphon tube to move vertically up and down to adjust the depth of the siphon orifice below the liquid surface; the peristaltic pump provides negative pressure to draw in the supernatant at a constant rate. The discharge valve 42 is located at the lowest point of the conical bottom of the settling container 1 and can be an electromagnetically driven ball valve, butterfly valve, or diaphragm valve. It is used to open after the siphoning is completed to discharge the concentrated target particle suspension to the collection unit. Figure 1 In the example, the siphon assembly 41 is fixed above the settling container 1 by a bracket, and the siphon tube extends into the container through a sealing gasket; the discharge valve 42 is fixed to the bottom of the container by a threaded connection or a flange connection. By setting up the liquid replacement unit 4, the liquid replacement unit replaces the liquid in the settling container. By first siphoning and then discharging from the bottom, precise separation of particles of different sizes is achieved.

[0038] The central control unit is connected to the rotary drive unit 2, the temperature control unit 3, and the liquid displacement unit 4, respectively. Specifically, the central control unit uses an industrial-grade microcontroller (such as an STM32F407) or a programmable logic controller (PLC), which integrates a processor, memory, input / output interfaces, and communication modules. The central control unit is connected to the motor driver of the rotary drive unit 2 via signal lines to send speed commands and receive encoder feedback; it is also connected to the temperature sensor of the temperature control unit 3 via signal lines to receive temperature data; and it is connected to the siphon motor and discharge valve of the liquid displacement unit 4 via signal lines to control their start / stop and operation. Figure 2 As shown, the central control unit also includes functional modules such as a temperature compensation algorithm module, a PID control module, and a timing management module. The temperature compensation algorithm module is used to execute the calculation logic to correct the Stokes settling time based on real-time temperature compensation; the PID control module is used to perform closed-loop regulation of the rotation speed of the rotary drive unit 2 to ensure constant speed; and the timing management module is used to coordinate the timing logic of each stage, such as rotation, static settling, and liquid replacement.

[0039] The rotary drive unit 2 is configured to drive the settling container 1 to rotate; the central control unit is configured to correct the Stokes settling time based on real-time temperature compensation to accurately control particle size separation. Specifically, after receiving real-time temperature data transmitted by the temperature control unit 3, the central control unit calls the internally stored Stokes' law formula and temperature-viscosity lookup table, calculates the fluid viscosity at the current temperature using a linear interpolation algorithm, and then calculates the corrected settling time. This correction process eliminates the influence of ambient temperature fluctuations on settling accuracy. Through the above hardware architecture, the automatic control device for fine particle settling sample preparation in this embodiment materializes each step into specific hardware modules and their connection relationships, realizing a binary binding between hardware and function. Under the unified coordination of the central control unit, each hardware module automatically completes the entire process of rotational anti-adsorption, temperature-compensated settling, and liquid displacement separation, significantly improving the automation level, recovery rate, and sorting accuracy of fine particle settling sample preparation.

[0040] In addition, the automatic control device for particle sedimentation sample preparation also includes a light-proof housing. The housing is made of opaque material and has built-in red light illumination with a wavelength greater than 590nm to meet the light-proof requirements for OSL sample preparation.

[0041] In this embodiment, an automatic control device for fine particle sedimentation sample preparation is constructed by organically combining a sedimentation container, a rotation drive unit, a temperature control unit, a liquid replacement unit, and a central control unit. Through the coordinated work of each module, the container is rotated before sedimentation, and the liquid shear force is used to detach the particles adsorbed on the wall and enter the suspension. This achieves the two core functions of "rotational anti-adsorption" and "temperature compensation," solving the problem of severe adsorption loss of fine particles. By correcting the sedimentation time according to the real-time temperature, the interference of ambient temperature fluctuations on the sorting accuracy is eliminated, solving the problem that the sorting accuracy is greatly affected by temperature.

[0042] like Figure 1 As shown, in addition to the above components, it also includes a lead screw support, guide rods, and a sliding block, forming a complete linear transmission structure. These three components together constitute the high-precision lifting and positioning carrier for the siphon tube, which is vertically assembled within the support frame above the settling container. Bearing seats are installed at both ends of the lead screw support to support the precision transmission lead screw (the threaded structure in the figure). The top of the support is fixed to the light-shielding outer shell of the entire machine, bearing the vertical loads of the siphon tube, pipeline, and pump body connector. Two parallel, smooth guide rods are symmetrically distributed on both sides of the lead screw, remaining parallel to it and passing through the slider throughout its entire length. These guide rods constrain the slider to move only in a vertical direction, eliminating radial offset and torsional sway caused by lead screw rotation, ensuring the verticality of the siphon tube's lifting and lowering, and preventing the suction nozzle from tilting and touching the inner wall of the container.

[0043] The slider is a composite sliding base with internal threaded holes for the lead screw and through holes for the guide rods. The lead screw and two guide rods are synchronously connected. A clamping seat is pre-installed on the side of the slider to lock and secure the siphon tube. When the lead screw is driven to rotate by a small servo motor at its top, the threaded transmission causes the slider to slide linearly up and down along the guide rods, thus precisely adjusting the siphon tube's immersion depth in the liquid. This, combined with the central control unit, achieves precise positioning of the siphon height below the liquid surface. The entire assembly of the lead screw support, guide rods, and slider is synchronized throughout the siphon lifting and lowering process, solving the problems of easy skew and insufficient positioning accuracy associated with single-screw lifting. This prevents uncontrolled extraction depth of the upper clear liquid due to siphon tube inlet position deviation and avoids the accidental aspiration of target sedimentary particles into the waste liquid.

[0044] In addition, the discharge valve is a solenoid ball valve. For example... Figure 1 The enlarged schematic diagram shows that the top electromagnetic actuator is connected to a ball inside the valve body via a valve stem, driving the ball to rotate. The valve body contains a ball and a through-hole. When the ball blocks the through-hole, the flow path is cut off; when the ball rotates to align the through-hole with the valve body's inlet and outlet, the flow path is open. The lower end of the valve body connects to a lower interface, which is connected to a discharge pipe for discharging the concentrated target particle suspension. The electromagnetic drive responds quickly and can open and close precisely; the discharged sample falls into the collection unit. The upper interface of the discharge valve is sealed to the conical bottom discharge port of the settling container via a gasket to prevent liquid leakage and avoid fine particle retention and blockage.

[0045] Figure 1 An ultrasonic dispersion unit is also provided above the temperature regulation element. The ultrasonic dispersion unit is equidistantly distributed along the outer wall of the sedimentation container 1. It is used to apply ultrasonic energy to the suspension in the sedimentation container 1. The micro-jet generated by the cavitation effect and the shock wave break up the particle agglomerates. At the same time, the liquid shearing action generated by the rotation causes the particles adsorbed on the wall to detach and be evenly dispersed in the suspension, thereby improving the efficiency and purity of subsequent sedimentation separation.

[0046] See Figure 2 It shows a flowchart of the implementation of the automatic control method for particle sedimentation sample preparation provided in an embodiment of the present invention, such as... Figure 2 As shown, the method specifically includes the following steps: S201, drives the rotary drive unit to rotate the settling container.

[0047] Specifically, after the suspension containing fine particles is injected into the settling container, the central control unit activates the rotary drive unit, causing the settling container to rotate at a low speed around its central axis. In this embodiment, this rotation before settling utilizes the liquid shear force generated by the rotation to detach fine particles that were originally adsorbed by electrostatic and van der Waals forces from the inner wall and bottom corners of the settling container, allowing them to re-enter the suspension. It should be understood that fine particles (especially those smaller than 10 μm) have a large specific surface area and are easily adsorbed onto glass or metal walls, often resulting in low recovery rates of the target particles in traditional static settling methods.

[0048] This embodiment reduces particle adsorption loss on the container wall by introducing a rotation step before sedimentation, thus improving the recovery rate of the target particles. In this embodiment, the rotation drive unit can be implemented using a stepper motor or a servo motor in conjunction with a reduction mechanism. Its rotation speed and duration can be adjusted according to the specific particle characteristics, as long as the adsorbed particles are detached from the wall.

[0049] S202: After the settling container stops rotating, the real-time temperature is acquired, and the Stokes settling time is compensated and corrected based on the real-time temperature.

[0050] Specifically, after the rotation step is completed, the central control unit stops the rotation drive unit, ensuring the settling container is stationary so that the particles can settle freely under gravity. At this time, the temperature control unit collects real-time temperature data of the suspension in the settling container and transmits it to the central control unit. Based on this real-time temperature data, the central control unit compensates for and corrects the preset Stokes settling time. This is because the dynamic viscosity of a fluid changes significantly with temperature; for example, the viscosity of water changes by about 11% between 20°C and 25°C. Without compensation, the actual settling time will deviate significantly from the theoretical calculation, thus affecting the accuracy of particle size separation.

[0051] This embodiment introduces a temperature compensation mechanism to eliminate the interference of ambient temperature fluctuations on sedimentation sorting accuracy, ensuring the accuracy and repeatability of sample preparation results. The corrected sedimentation time can more realistically reflect the sedimentation pattern of target particles under the current temperature conditions.

[0052] S203, based on the corrected Stokes settling time, controls the liquid replacement unit to replace the liquid in the settling container.

[0053] Specifically, after calculating the corrected settling time, the central control unit initiates a timing function. When the corrected settling time is reached, it means that particles of the target size have settled to the predetermined depth or the bottom of the container, while particles of other sizes remain suspended in the upper liquid. At this point, the central control unit controls the liquid replacement unit to remove the upper clear liquid containing non-target particles from the settling container, while retaining the concentrate containing the target particles, thereby achieving the separation of particles of different sizes. The liquid replacement unit can be implemented using fluid control components such as a siphon assembly, a peristaltic pump, or a solenoid valve. By precisely controlling the timing of liquid replacement, this embodiment ensures the accuracy of particle size separation and avoids separation errors caused by insufficient human operating experience.

[0054] In this embodiment, by coordinating the timing of the three steps described above, particularly the process flow of "first rotating to prevent adsorption, then allowing static settling and temperature compensation," a standardized automated control method for fine particle sedimentation sample preparation is provided. This method solves the problem of severe fine particle adsorption loss by driving the container to rotate before sedimentation, utilizing the liquid shear force generated by the rotation to detach particles adsorbed on the wall and allow them to enter the suspension. By correcting the sedimentation time based on real-time temperature, the interference of ambient temperature fluctuations on sorting accuracy is eliminated, resolving the issue of sorting accuracy being greatly affected by temperature. This not only solves the core problems of fine particle adsorption loss and temperature-related impacts on sorting accuracy but also achieves automated control of the sample preparation process, eliminating human interference and significantly improving the quality and efficiency of fine particle sample pretreatment in applications such as optically stimulated luminescence dating.

[0055] Based on the aforementioned embodiments, the rotational speed parameters of the rotary drive unit are further optimized. Specifically, the central control unit drives the rotary drive unit to rotate the settling container at a preset rotational speed, and after a preset time, controls the rotary drive unit to stop rotating. The preset rotational speed ranges from 0.5 to 5 rpm.

[0056] It should be understood that the rotational speed is not set arbitrarily, but is based on precise calculations using particle force analysis and fluid dynamics principles. In this embodiment, the lower limit of the preset rotational speed of 0.5 rpm is determined based on the critical rotational speed at which particles detach from the wall. Fine particles (especially those smaller than 10 μm) are adsorbed by van der Waals forces on the wall in a suspension. For particles to detach from the wall, the liquid shear force generated by rotation must be greater than the van der Waals adhesion force.

[0057] According to the critical speed formula: in, For van der Waals adhesion, For particle mass, Let be the radius of rotation.

[0058] Taking 4μm micrometer quartz particles as an example, van der Waals adhesion The value is 1.25 × 10⁻⁸ N, and the particle mass is... Quartz density =2650 kg / m³, diameter =4×10⁻⁶ m, The distance from the particle to the center of rotation is taken as 0.05 m, and the critical speed calculated using the formula for calculating the critical speed is approximately 0.3 rpm. Considering the irregularity of particle shape and the influence of wall roughness in actual working conditions, this embodiment adopts a safety factor of approximately 1.67, setting the lower limit of the speed to 0.5 rpm. If the speed is lower than this lower limit, the liquid shear force is insufficient to overcome the van der Waals force, and the particles will still be adsorbed on the wall surface, failing to effectively improve the recovery rate.

[0059] On the other hand, the preset upper limit of 5 rpm is determined based on the Reynolds number limitation in fluid mechanics. During sedimentation sample preparation, it is essential to ensure that the suspension is in a laminar flow state to avoid turbulence interfering with subsequent static sedimentation and stratification. When the rotation speed exceeds 5 rpm, the Reynolds number of the liquid in the sedimentation container will exceed the critical value, generating a significant turbulence effect. This causes particles that have already settled or are settling to resuspend or mix, severely affecting the accuracy of particle size separation. Therefore, setting the upper limit of the rotation speed to 5 rpm ensures that particles effectively detach from the wall while also ensuring that the liquid quickly returns to stillness after rotation stops, without affecting the subsequent gravity sedimentation process.

[0060] According to Newton's law of internal friction, the formula for the shear stress at the wall is: in, For the dynamic viscosity of the liquid, The circumferential velocity of the liquid. This is the distance from the wall. This represents the velocity gradient near the wall.

[0061] Theoretical estimates show that the shear stress generated at a rotation speed of 0.5-5 rpm is sufficient to overcome the van der Waals adhesion of 4-11 μm fine particles, thereby achieving effective detachment.

[0062] For a rotating container, the linear velocity of the wall... =2πrn / 60 (where n is the number of revolutions per minute), assuming a linear velocity distribution within the boundary layer, the shear stress can be approximated as: ,in, Boundary layer thickness (approximately equal to particle diameter) The viscous shear force acting on the particles is: .

[0063] Particle detachment conditions: ( (Equivalent adhesion force in actual water-based suspensions).

[0064] In theoretical calculations, taking 4μm quartz particles as an example, the dynamic viscosity of the liquid... =1.0×10⁻³ Pa·s (water at 20℃), particle diameter =4×10⁻⁶m, take the radius of the container. =0.05 m. The dry density of 4 μm quartz particles. =1.25×10⁻⁸ N; however, numerous studies have shown that in water-based suspensions, the actual effective adhesion force can be reduced by 2–3 orders of magnitude due to the repulsion of the hydration layer, the electric double layer force, and the influence of surface roughness. Based on the fluid shear force model and experimental experience, we take... =3.3×10⁻¹¹ N, substituting, we get: =3.3×10-11 / 1.0×10-3×π×4×10-6≈2.6×10-3 m / s Corresponding speed: =60×0.0026 / 2π×0.05≈0.5 rpm To ensure reliability under various operating conditions, the lower limit of the rotational speed is set at 0.5 rpm. The upper limit of 5 rpm is determined based on the critical Reynolds number to ensure that the settling process remains in a laminar state (Re < 2000).

[0065] To avoid flow disturbances caused by rotation affecting particle settling accuracy, the liquid flow within the container must remain laminar. For a rotating cylindrical container, the Reynolds number is defined as: Where ω = 2πn / 60, and ν is the kinematic viscosity of water (approximately 1 × 10⁻⁶ m² / s). Let... =0.05 m, when At 5 rpm, ω = 2π × 5 / 60 = 0.53 rad / s. =0.53×(0.05)2 / 1×10-6≈1325, this value is less than the critical Reynolds number (generally considered to be...). <2000 indicates laminar flow. Higher rotation speeds may cause turbulence, disrupting the settled particle layer and reducing separation purity.

[0066] In this embodiment, a balance mechanism between "anti-adsorption" and "sedimentation protection" is established by limiting the rotational speed of the rotary drive unit to the range of 0.5 to 5 rpm. This parameter range solves the problem of fine particle adsorption loss and avoids the introduction of new interference factors due to excessive rotational speed, thus ensuring the stability and reliability of the sedimentation sample preparation process.

[0067] Based on the aforementioned embodiments, the dispersion and anti-adsorption stage (step S201) is further optimized. Specifically, the sedimentation sample preparation device also includes an ultrasonic dispersion unit, and the central control unit is connected to the ultrasonic dispersion unit; while driving the rotary drive unit, the central control unit also controls the ultrasonic dispersion unit to apply ultrasonic energy to the suspension in an intermittent mode. The frequency of ultrasonic energy application is 40 to 80 kHz, each application lasts for 30 to 60 seconds, and the interval is 2 minutes.

[0068] It should be understood that fine particles in suspension not only face the problem of wall adsorption, but also readily form agglomerates due to van der Waals forces and electrostatic forces. If these agglomerates are not broken up, their actual settling velocity will be greater than the single-particle velocity predicted by Stokes' law, leading to a decrease in particle size separation accuracy.

[0069] In one possible implementation, an ultrasonic dispersion unit is introduced, utilizing the shock waves and microjets generated by the cavitation effect of ultrasound in the liquid to break the aggregation bonds between particles, causing the aggregates to deagglomerate. However, the ultrasonic cavitation effect generates a significant thermal effect while releasing energy. If a continuous ultrasonic mode is used, the suspension temperature will rise sharply in a short period of time, leading to uncontrollable changes in fluid viscosity, which in turn seriously affects the temperature compensation accuracy of the subsequent static settling stage (step S202).

[0070] This embodiment employs an intermittent mode. Specifically, the applied ultrasonic energy frequency is set to 40 to 80 kHz, a range determined based on cavitation threshold theory. Within this frequency range, the cavitation threshold acoustic pressure of the water-based suspension is approximately 0.2 to 0.5 MPa, enabling stable cavitation effects and effectively breaking up agglomerates of 4-11 μm fine particles. If the frequency is too low (e.g., below 20 kHz), the cavitation bubbles become too large, generating excessively violent shock waves that may damage the particle surface and affect the stability of the OSL signal. Conversely, if the frequency is too high (e.g., above 100 kHz), the cavitation threshold increases sharply, making it difficult to generate effective cavitation effects. Furthermore, each application lasts 30 to 60 seconds, with an interval of 2 minutes. This interval ratio (approximately 1:3 to 1:5) is designed based on heat conduction estimation. The heat generated during ultrasonic operation can be dissipated to the environment through the container wall during the interval, ensuring the overall temperature rise of the suspension remains below 2°C, thereby guaranteeing the effectiveness of the subsequent temperature compensation algorithm.

[0071] The temperature of the suspension may rise too much after ultrasound is used for a period of time, which may introduce errors in the sedimentation time calculation. Therefore, in one possible implementation, the preset time is 10 minutes.

[0072] In this embodiment, by configuring the ultrasonic dispersion unit to work in conjunction with the rotary drive unit and employing a specific intermittent mode and frequency parameters, a balance is achieved between "dispersion and anti-agglomeration" and "temperature rise control." The liquid shear force generated by rotation causes particles to detach from the wall surface, while the cavitation effect generated by ultrasound breaks up agglomerates. The synergistic effect of both significantly improves the monodispersity of fine particles in the suspension, laying the foundation for subsequent high-precision sedimentation separation. At the same time, the intermittent mode effectively avoids the interference of thermal effects on sedimentation accuracy, ensuring the reliability of the sample preparation process.

[0073] Based on the aforementioned embodiments, the specific implementation process of temperature compensation correction is described in detail. Specifically, the central control unit compensates for and corrects the Stokes settling time based on the relationship between fluid viscosity and temperature. It should be understood that the dynamic viscosity of a fluid (such as water) is a key parameter affecting particle settling velocity and is extremely sensitive to temperature changes. For example, the dynamic viscosity of water at 20°C is approximately 1.002 × 10⁻³ Pa·s, while at 25°C it drops to approximately 0.890 × 10⁻³ Pa·s, a change of about 11%. Without considering temperature compensation, the actual settling time will deviate from the theoretically calculated value when the ambient temperature fluctuates, leading to a decrease in particle size separation accuracy. This embodiment achieves dynamic correction of the settling time by establishing a functional relationship between fluid viscosity and temperature.

[0074] Specifically, the Stokes settling time is calculated based on Stokes' law. The central control unit determines the Stokes settling time based on the diameter of the target particle, the density difference between the target particle and the suspension, the settling height, and the acceleration due to gravity. in, For settlement height, The particle diameter is Particle density, For fluid density, This is the acceleration due to gravity.

[0075] In this embodiment, the central control unit pre-stores the above formula, and the user only needs to input the target particle diameter. (e.g., 4μm or 11μm) The system can automatically calculate the theoretical settling time under standard conditions based on the preset particle density (e.g., quartz density 2650kg / m³), fluid density (water density 1000kg / m³) and settling height (e.g., 0.1m).

[0076] Furthermore, the central control unit calculates the corrected Stokes settling time based on the preset Stokes settling time at a reference temperature and the ratio of the fluid viscosity at the real-time temperature to the fluid viscosity at the reference temperature. This embodiment uses a ratio method for correction, and the correction formula is as follows: in, This is the corrected actual settlement time. The standard settling time at the reference temperature. The fluid viscosity at real-time temperature. This represents the fluid viscosity at the reference temperature.

[0077] The physical meaning of this formula is that settling time is directly proportional to fluid viscosity. When temperature increases and viscosity decreases, the settling time should be shortened accordingly; conversely, it should be lengthened. This ratio correction eliminates the influence of temperature fluctuations on settling accuracy.

[0078] To obtain the fluid viscosity at real-time temperature The central control unit calculates the fluid viscosity at real-time temperature using linear interpolation, based on a pre-stored temperature-to-fluid viscosity correspondence table. Specifically, the central control unit's non-volatile memory stores a standard temperature-viscosity lookup table, for example: When the temperature control unit acquires the real-time temperature T (e.g., 22℃), the central control unit first locates the temperature range of T in the lookup table (20℃ to 25℃ in this example), and then calls the linear interpolation formula: Taking a measured temperature of 22℃ as an example, =20℃, =25℃, substituting into the formula, we get: η (22℃) = 1.002 + (0.890 - 1.002) (22-20) / (25-20)≈0.957×10⁻³Pa·s. Compared with the complex exponential fitting formula, the linear interpolation method has a small computational load, is suitable for real-time processing in embedded systems such as microcontrollers, and its accuracy fully meets the engineering requirements of sedimentation sample preparation when the interval between adjacent temperature points is small (such as 5℃).

[0079] In this embodiment, the reference temperature is the standard temperature. The central control unit calculates the standard settling time based on Stokes' law at the standard temperature. The standard settling time is the Stokes settling time at the standard temperature. Preferably, 20°C is selected as the standard temperature in this embodiment because 20°C is close to the ambient temperature of a typical laboratory environment, and the fluid viscosity data at this temperature is a commonly used physical constant, which is convenient for calibration and calculation. Of course, depending on the actual application scenario, other temperatures (such as 25°C) can also be selected as the standard temperature; only the pre-stored viscosity data needs to be adjusted accordingly.

[0080] The temperature compensation process in this embodiment is illustrated below with a specific example: Assume the target particle is a 4μm quartz particle with a settling height of 0.1m. First, the central control unit calculates the settling time at a standard temperature of 20℃. Substituting into Stokes' formula, we get Approximately 7200 seconds. If the real-time temperature collected by the temperature control unit is 22℃, the central control unit first calculates the dynamic viscosity of water at 22℃ using linear interpolation. η (22℃)≈0.957×10⁻³Pa·s, then the ratio correction formula is used to calculate the actual settlement time: t (22℃) = 7200 × (0.957 / 1.002) ≈ 6870 seconds. It can be seen that due to a 2℃ increase in temperature, the settling time is shortened by approximately 330 seconds. If no compensation is made and the time is still set at 7200 seconds, some particles smaller than 4μm will settle to the bottom, severely reducing the sorting accuracy. This embodiment, through the aforementioned temperature compensation mechanism, controls the settling time error caused by temperature fluctuations to within 2%, significantly improving the accuracy and reliability of fine particle settling sample preparation.

[0081] Based on step S203 in the aforementioned embodiments, the specific operation process of liquid replacement is described in detail. Specifically, the central control unit controls the liquid replacement unit to draw in the upper clear liquid by siphoning, and then discharges the concentrated target particle suspension by bottom discharge to collect the target particles.

[0082] It should be understood that after the settling in step S202, the suspension in the settling container forms a distinct stratified structure: the upper layer is a clear liquid containing particles smaller than the lower limit of the target particle size (e.g., less than 4 μm), the lower layer is a concentrated liquid containing particles within the target particle size range (e.g., 4-11 μm), and the bottom layer contains coarse particles larger than the upper limit of the target particle size (e.g., greater than 11 μm). This embodiment achieves precise separation of particles of different sizes through a two-step separation strategy of "siphoning first, then discharging".

[0083] Furthermore, the central control unit sets the siphon position at a height of 80% to 90% below the liquid surface and controls the extraction of the upper clear liquid at a constant rate, ensuring that the target particles are not resuspended.

[0084] Regarding the setting of the siphon position, this embodiment uses precise calculations based on Stokes's law of sedimentation and the boundary layer theory of fluid dynamics. At the end of the sedimentation process, the sedimentation depth of target particles (e.g., 4μm particles) is approximately 90% to 95% below the liquid surface, while non-target particles (e.g., particles smaller than 4μm) are mainly distributed within the range of 0% to 80% below the liquid surface. If the siphon position is set too shallow (e.g., 50% below the liquid surface), a large number of non-target particles will remain in the container, reducing the separation purity; if the siphon position is set too deep (e.g., 95% below the liquid surface), it is very easy to suck up the settled target particles, resulting in a decrease in recovery rate. Therefore, setting the siphon position at 80% to 90% below the liquid surface achieves the best balance between "removing non-target particles" and "retaining target particles". In specific implementation, the liquid replacement unit includes a movable siphon assembly 41, and the central control unit drives the siphon assembly 41 to descend to the preset depth via a precision lead screw, with a positioning accuracy of ±0.1mm.

[0085] Regarding the setting of the constant flow rate, this embodiment estimates it based on the critical suspension velocity in fluid mechanics. When liquid is drawn out, a local velocity field is generated near the siphon. If the flow rate is too high, the resulting shear force will exceed the critical suspension shear force of the settled particles, causing the particles to resuspend and be drawn away with the supernatant, resulting in sample loss. According to theoretical analysis and experimental data reported in relevant literature, for fine-particle quartz samples of 4-11 μm, when the siphon rate exceeds 10 mL / min, the bottom sedimentation layer begins to show significant disturbance; when the rate is controlled below 5 mL / min, the sedimentation layer remains stable. Therefore, this embodiment sets the default siphon rate to 5 mL / min, a safe value derived from fluid mechanics calculations and existing literature data, ensuring efficient drainage without causing resuspension of the target particles. Of course, users can also fine-tune the rate on the human-computer interface according to the specific concentration, particle size distribution, or viscosity characteristics of the sample, for example, appropriately reducing the rate when processing high-concentration samples or appropriately increasing the rate when processing large-particle samples.

[0086] After the siphon process is completed, the central control unit controls the discharge valve 42 located at the lowest point of the conical bottom of the settling container to open, discharging the concentrated target particle suspension to the collection unit (such as a filtration device or a dating disc). Because the settling container adopts a conical bottom design, the target particles are concentrated at the lowest point under the action of gravity. A high collection rate can be achieved by discharging from the bottom, avoiding the loss of residue on the container wall in the traditional pouring method.

[0087] In this embodiment, by precisely controlling the siphon position and constant rate, combined with a bottom discharge method, high-precision and high-recovery particle size separation is achieved. This automated separation process eliminates the uncertainties of manual operation and significantly improves the repeatability and reliability of fine particle sedimentation sample preparation.

[0088] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0089] In one specific embodiment, taking the preparation of fine-particle (4-11 μm) samples in the field of optically stimulated luminescence (OSL) dating as an example, the complete operational process and technical effects of the present invention in a practical application scenario are described in detail. It should be understood that sample pretreatment for OSL dating has certain requirements for particle size purity and recovery rate, and traditional manual sedimentation methods sometimes struggle to simultaneously achieve both efficiency and stability. This embodiment verifies the practical value of the present invention in improving sample preparation quality through a two-step sample preparation process.

[0090] The first step is to remove coarse particles (particle size greater than 11μm).

[0091] The sample suspension, after chemical pretreatment (removal of organic matter and carbonates), was injected into sedimentation container 1, with the liquid level controlled at the 100mm mark. The central control unit was set to an upper limit of 11μm for the target particle size. The dispersion and anti-adsorption phase was first executed: the central control unit drove the rotary drive unit 2 to rotate sedimentation container 1 at 2 rpm, while simultaneously controlling the ultrasonic dispersion unit 5 to operate in intermittent mode (45 seconds of ultrasound followed by a 2-minute interval) for 10 minutes. The liquid shear force generated by the rotation caused the particles adsorbed on the wall to detach, and the ultrasonic cavitation effect broke up the agglomerates; the combined effect of these two mechanisms ensured the monodispersity of the particles in the suspension. Then, the static sedimentation phase began: rotation and ultrasound were stopped, and the temperature control unit 3 collected the real-time temperature (assumed to be 22℃). The central control unit calculated the corrected sedimentation time for 11μm particles at the current temperature according to Stokes' law. According to Stokes' law, the particle settling velocity is proportional to the square of the particle size; particles larger than 11μm settle faster and reach the bottom of the container in a shorter time. After the timing is completed, the central control unit controls the siphon assembly 41 of the liquid replacement unit 4 to descend to 80% of the liquid level, and aspirates the upper suspension containing particles smaller than 11 μm at a constant rate of 5 mL / min, transferring it to a clean intermediate container for temporary storage. The bottom discharge valve 42 discharges and discards the coarse particles (greater than 11 μm) that have settled at the bottom of the container. Thus, the first step of sample preparation is complete, successfully removing the coarse particulate component from the sample.

[0092] The second step is to collect the target particles (particle size 4-11 μm).

[0093] The upper suspension collected in the first step is reinjected into sedimentation container 1. The central control unit sets the target particle size lower limit to 4μm. The dispersion and anti-adsorption stage is executed again: the rotation and ultrasonic parameters are the same as in the first step. Then, the static sedimentation stage begins: the temperature control unit 3 collects the real-time temperature (assuming ambient temperature fluctuations, the actual measurement is 25℃), and the central control unit calculates the corrected sedimentation time for 4μm particles at 25℃. Because the sedimentation rate of 4μm particles is slower, the sedimentation time is significantly longer than in the first step. After the timing is completed, the central control unit controls the siphon assembly 41 to draw up and discharge the clear liquid containing particles smaller than 4μm from the upper layer. Finally, the bottom discharge valve 42 is opened to discharge the concentrated 4-11μm target particle suspension to the dating disc or vacuum filter, completing the sample preparation.

[0094] This embodiment achieves precise extraction of target particles ranging from 4 to 11 μm through the aforementioned two-step process. The technical effectiveness of this invention is then verified using specific data.

[0095] Regarding the actual effect of temperature compensation: During the second settling process, if the ambient temperature fluctuates from the standard temperature of 20℃ to 25℃, the dynamic viscosity of water will decrease from 1.002×10⁻³ Pa·s to 0.890×10⁻³ Pa·s, a change of approximately 11%. Without temperature compensation, if the theoretical settling time at 20℃ is used, the actual settling time will be shortened by approximately 11%, causing some particles smaller than 4μm to fail to settle to the predetermined depth before the timer ends, thus mixing into the target particles and reducing the sorting purity. This embodiment uses a temperature compensation algorithm in the central control unit to correct the settling time based on the real-time temperature of 25℃, controlling the settling time error to within 2%, ensuring the accuracy of particle size separation. Experimental data shows that within a temperature range of 10-30℃, the temperature compensation mechanism of this invention can control the settling time deviation to within 2%, significantly better than the 11% deviation without compensation.

[0096] Regarding the effect of synergistic rotation and ultrasound in improving recovery rate: Traditional manual sedimentation methods typically result in only 50%-70% recovery rate of target particles due to significant particle adsorption losses. This embodiment utilizes the liquid shear force generated by the rotation drive unit 2 to continuously move particles away from the container wall, combined with the cavitation effect of the ultrasonic dispersion unit 5 to break up agglomerates and resuspend adsorbed particles, effectively solving the problem of fine particle adsorption loss. Using the device and method of this invention, the recovery rate of target particles is improved compared to traditional manual methods, making it suitable for processing rare archaeological samples and thus improving sample utilization.

[0097] In this embodiment, the feasibility and effectiveness of the technical solution of the present invention in practical applications were verified through the complete operation of the two-step sample preparation process. The synergistic effect of technical features such as rotational anti-adsorption, ultrasonic dispersion, temperature compensation, and constant-rate siphon not only improves the recovery rate and sorting purity of target particles, but also realizes the automation and standardization of the sample preparation process, eliminates human experience differences, and significantly improves the quality and efficiency of sample pretreatment for optically stimulated luminescence dating.

[0098] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not detailed or described in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Unless otherwise specified or in conflict with logic, the terminology and / or descriptions between different embodiments are consistent and can be referenced interchangeably. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0099] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. An automatic control method for particle sedimentation sample preparation, characterized in that, The automatic control device for particle sedimentation sample preparation includes: a central control unit, a rotary drive unit, a temperature control unit, and a liquid replacement unit. The rotary drive unit is used to drive the sedimentation container to rotate. The temperature control unit is used to acquire the real-time temperature of the suspension in the sedimentation container and adjust the temperature of the suspension. The liquid replacement unit is used to replace the liquid in the sedimentation container. The method includes: The rotary drive unit is driven to rotate the settling container. After the settling container stops rotating, the real-time temperature is acquired, and the Stokes settling time is compensated and corrected based on the real-time temperature. The liquid replacement unit is controlled to replace the liquid in the settling container based on the corrected Stokes settling time.

2. The method according to claim 1, characterized in that, The Stokes settling time is compensated and corrected based on the relationship between fluid viscosity and temperature.

3. The method according to claim 2, characterized in that, The Stokes settling time is calculated based on Stokes' law; The Stokes settling time is determined based on the diameter of the target particle, the density difference between the target particle and the suspension, the settling height, and the gravitational acceleration.

4. The method according to claim 3, characterized in that, The Stokes settling time is corrected based on the real-time temperature compensation, including: The corrected Stokes settling time is calculated based on the Stokes settling time at a preset reference temperature and the ratio of the fluid viscosity at the real-time temperature to the fluid viscosity at the reference temperature.

5. The method according to claim 4, characterized in that, The fluid viscosity at the real-time temperature is calculated by linear interpolation, which is determined based on a pre-stored table of the correspondence between temperature and fluid viscosity.

6. The method according to claim 4, characterized in that, The reference temperature is the standard temperature; the standard settling time is the Stokes settling time at the standard temperature.

7. The method according to claim 1, characterized in that, The rotary drive unit is driven to rotate the settling container at a preset speed, and after a preset time, the rotary drive unit is controlled to stop rotating.

8. The method according to claim 7, characterized in that, The preset speed range is 0.5 to 5 rpm.

9. The method according to claim 1, characterized in that, The sedimentation sample preparation device further includes an ultrasonic dispersion unit; the central control unit is connected to the ultrasonic dispersion unit. The system includes, while driving the rotary drive unit, controlling the ultrasonic dispersion unit to apply ultrasonic energy to the suspension in an intermittent mode.

10. An automatic control device for fine particle sedimentation sample preparation, characterized in that, include: Settling containers; A rotary drive unit, connected to the settling container, is used to drive the settling container to rotate; A temperature control unit is used to acquire the real-time temperature of the suspension in the settling container and adjust the temperature of the suspension. A liquid replacement unit is used to replace the liquid in the settling container; The central control unit is connected to the rotary drive unit, the temperature control unit, and the liquid displacement unit, respectively, and is used to perform the method as described in any one of claims 1 to 9.

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