A method and apparatus for measuring viscosity

Abstract

This application relates to the field of viscosity measurement technology, and provides a viscosity measurement method and apparatus. The method involves establishing a negative pressure at a constant rate at the top of a container, causing the internal pressure to linearly decrease from atmospheric pressure to a target value. At the instant the negative pressure begins to build, a magnetic buoy is simultaneously released via the same control signal, achieving time synchronization between the negative pressure initiation and the buoy release. During the buoy's descent, the time taken for the buoy to pass through the first and second detection positions on the guide channel, as well as the real-time liquid surface position of the liquid to be measured, are simultaneously detected. These two data pairs are paired to form a time-series correlated data pair, enabling the synchronous acquisition and correlation of multiple parameters. Based on at least three time-series correlated data pairs and a pre-calibrated correlation relationship, the dynamic viscosity value of the liquid to be measured is determined. Through collaborative verification of multiple data pairs and calibration of the pre-calibrated correlation relationship, the accuracy and repeatability of viscosity measurement are improved, making it suitable for liquids with different viscosity ranges.

Description

Technical Field

[0001] This application relates to the field of viscosity measurement technology, and in particular to a viscosity measurement method and apparatus. Background Technology

[0002] Currently, the commonly used viscosity measurement methods in the industry mainly include capillary viscometer method, rotational viscometer method and float viscometer method. Among them, the float viscometer method is the most widely used in medium and low viscosity liquid measurement scenarios because of its simple structure, convenient operation and no need for complicated sample pretreatment.

[0003] As industrial production continues to demand higher accuracy, stability, and real-time performance in viscosity measurement, existing buoy-based viscosity measurement technology is gradually moving towards automation and precision. Automated measurement equipment based on sensor detection and microcontroller control has emerged, enabling automatic acquisition of buoy descent time and liquid surface position, as well as preliminary data processing. However, the overall technical solution has not yet broken through the limitations of traditional measurement logic.

[0004] Existing technologies only reduce the pressure inside the container by evacuating air with a vacuum pump, without precisely controlling the rate of pressure reduction. This results in non-linear fluctuations in the pressure reduction process, leading to instability in the rate at which the liquid being tested is drawn into the container through the capillary tube. The rising liquid level causes impacts and fluctuations, interfering with the free-falling motion of the buoy and causing deviations in the detection of buoy motion parameters, thus affecting the accuracy of viscosity measurements. Furthermore, the negative pressure activation and buoy release are often controlled independently, with signal transmission delays or misaligned timing between the two. This mismatch between the buoy release time and the start time of the rising liquid level results in abnormalities in the buoy's contact with the liquid and its trajectory during descent, further exacerbating measurement errors.

[0005] Existing technologies rely on a single parameter to calculate liquid viscosity, which cannot avoid errors caused by instantaneous interference. At the same time, they do not consider the dynamic coupling relationship between the buoy's descent and the rise of the liquid surface, resulting in insufficient validity and reliability of the measurement data. Furthermore, they are mostly based on a single buoy descent time or liquid surface rise height, which makes the measurement results greatly affected by factors such as fluctuations in operating conditions and changes in ambient temperature, thus failing to meet the requirements for high-precision measurement.

[0006] Based on the shortcomings of the prior art, the technical problem to be solved in this application is how to improve the accuracy, stability and reliability of viscosity measurement. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this application provides a viscosity measurement method and apparatus.

[0008] In a first aspect, this application provides a viscosity measurement method, which includes: establishing a negative pressure at a constant rate at the top of a container, causing the air pressure inside the container to decrease linearly from atmospheric pressure to a target value, and drawing the liquid to be measured upward into the container through a capillary tube set at the bottom of the container;

[0009] At the instant the negative pressure begins to build, a magnetic buoy located inside the container and above the liquid to be tested is released synchronously via the same control signal and falls freely in the guide channel set along the axis of the container.

[0010] During the descent of the magnetic buoy, the time it takes for the magnetic buoy to pass through the first and second detection positions on the guide channel is continuously detected to calculate the descent time. At the same time, the real-time liquid level position of the liquid to be tested in the container is detected to obtain the liquid level rise height. These are paired to form a time-series correlation data pair.

[0011] Based on at least three time-series correlation data pairs, the dynamic viscosity value of the liquid to be tested is determined through a pre-calibrated correlation relationship.

[0012] As an optional implementation, establishing negative pressure includes:

[0013] The real-time air pressure value inside the container and the real-time liquid level rise rate of the liquid to be measured are obtained, and the rate deviation between the real-time liquid level rise rate and the preset liquid level reference slope is calculated.

[0014] The pumping rate of the vacuum pump is adjusted based on the rate deviation to maintain the gas pressure inside the container decreasing linearly from atmospheric pressure to the target value at the constant rate.

[0015] As an optional implementation, the constant rate characterizes the linear decrease slope of the internal air pressure of the container over time, that is, the decrease in air pressure per unit time remains constant, which is used to provide a constant driving force for the capillary tube at the bottom of the container to draw the liquid to be tested into the container; the constant rate is determined in advance by calibration experiments using a standard viscosity liquid.

[0016] As an optional implementation, the free fall process of the magnetic buoy includes:

[0017] At the instant the negative pressure begins to build, a magnetic buoy placed inside the container and above the liquid to be tested is released synchronously via the same control signal, and the magnetic buoy is restricted to displacement along the container axis only via a guide channel;

[0018] Using the constant rate of linear decrease in air pressure inside the container as a timing reference, the detection signal of the magnetic buoy's descent position is synchronously calibrated.

[0019] The contact time between the magnetic buoy and the liquid to be tested is determined based on the real-time liquid level position, and the descent path after the contact time is determined as the descent detection interval.

[0020] As an optional implementation, the calculation of the fall time includes:

[0021] Determine the effective detection segment within the fall detection interval for the first and second detection positions on the guide channel;

[0022] Using the constant rate as a timing reference, the acquisition time of the detection signals at the first detection position and the second detection position are respectively time-calibrated.

[0023] The initial descent time is obtained by acquiring the time difference between the first and second detection positions within the effective detection segment after calibration of the magnetic buoy.

[0024] The initial descent time is corrected by combining the real-time liquid level rise rate to obtain the descent time.

[0025] As an optional implementation, determining the liquid level rise includes:

[0026] At the instant the negative pressure begins to build, the initial liquid level position inside the container is acquired synchronously, and the detection signal of the real-time liquid level position is time-aligned using the constant rate as the timing reference.

[0027] By combining the contact time between the magnetic buoy and the liquid to be measured, the real-time liquid surface position before and after the contact time is calibrated in segments, and the position difference between the calibrated real-time liquid surface position and the initial liquid surface position is calculated to obtain the initial liquid surface rise height.

[0028] The initial liquid level rise height is dynamically verified based on the real-time liquid level rise rate to obtain the liquid level rise height.

[0029] As an optional implementation, the pairing to form a time-series associated data pair includes:

[0030] Using the constant rate as a timing reference, the descent time and the liquid level rise height are synchronized twice in a timing sequence.

[0031] Based on the contact time, the time sequence is divided into multiple time segments of equal duration. The average descent time and average liquid level rise height of each time segment are extracted and matched accordingly to form basic correlation data pairs.

[0032] Based on the coupling relationship between the real-time liquid level rise rate and the constant rate, the rationality of the basic correlation data pairs is verified, and the data pairs that pass the verification are used as time-series correlation data pairs.

[0033] As an optional implementation, the pre-defined association relationships include:

[0034] Select at least three standard viscosity liquids with different known dynamic viscosities and measure the time series correlation data pairs for the corresponding time series segments;

[0035] Using the constant rate as the time series reference, the average descent time and average liquid level rise height in each set of time series correlation data pairs are fitted with the known dynamic viscosity and real-time liquid level rise rate of the corresponding standard viscosity liquid to establish a mapping relationship for different time series segments, which serves as a pre-calibrated correlation relationship.

[0036] As an optional implementation, determining the dynamic viscosity value of the liquid to be tested includes:

[0037] The average descent time, average liquid level rise height, constant rate and real-time liquid level rise rate of the liquid under test are matched with the pre-calibrated correlation to extract the corresponding initial viscosity value.

[0038] Based on the coupling deviation between the real-time liquid level rise rate and the constant rate during the current measurement process, the initial viscosity value is dynamically corrected.

[0039] The initial viscosity value after correction is checked for consistency. If the deviation of the viscosity value determined three times in a row is less than the preset deviation threshold, the average viscosity value is taken as the dynamic viscosity value of the liquid to be tested. Otherwise, the dynamic viscosity value is determined again after reconstructing the time-series correlation data pair.

[0040] Secondly, this application provides a viscosity measuring device, which includes: a suction module, including a container, a capillary tube disposed at the bottom of the container, and a vacuum pump connected to the top of the container via a regulating valve. The regulating valve is used to establish a negative pressure in the container at a constant rate, so that the liquid to be measured is sucked upward through the capillary tube.

[0041] The falling module includes a magnetic buoy disposed inside the container and above the liquid to be tested, a magnetic holding mechanism for adsorbing and holding the magnetic buoy, and a guide channel disposed along the axis of the container.

[0042] The magnetic buoy is released simultaneously with the start of the vacuum pump by the same control signal, allowing it to fall freely in the guide channel.

[0043] The detection module includes a first sensor group arranged vertically along the guide channel and a second sensor group disposed on the side wall of the container. The first sensor group is used to detect the falling time of the magnetic buoy at different detection positions, and the second sensor group is used to detect the rise height of the liquid surface of the liquid to be tested.

[0044] The processing module determines the dynamic viscosity value of the liquid under test based on the time-series correlation data output by the first and second sensor groups through a pre-calibrated correlation relationship.

[0045] Compared with the prior art, the beneficial effects of this application are: by establishing a negative pressure at a constant rate at the top of the container, the air pressure inside the container is linearly reduced from atmospheric pressure to the target value, ensuring that the rate at which the liquid to be tested is drawn into the container through the capillary is stable, and that there is no impact or fluctuation during the rise of the liquid surface, thus providing a stable and undisturbed free-fall environment for the magnetic buoy and reducing the interference of liquid surface fluctuations on the detection of buoy motion parameters.

[0046] At the moment the negative pressure begins to build, the magnetic buoy is released synchronously through the same control signal to achieve time synchronization between the start of negative pressure and the release of the buoy. This ensures that the release time of the buoy is precisely matched with the start time of the rise in the liquid level, and that the buoy's descent and the rise in the liquid level are coordinated in time. This avoids abnormal buoy trajectory and unstable contact with the liquid due to timing deviations, and improves the accuracy of parameter detection.

[0047] During the buoy's descent, the time it takes for the buoy to pass the first and second detection positions on the guide channel, as well as the real-time liquid level of the liquid to be measured, are simultaneously detected. These two data are then paired to form a time-series correlated data pair, enabling the synchronous acquisition and correlation of multiple parameters in time. This avoids single-parameter errors caused by instantaneous interference, improves the effectiveness and reliability of the measurement data, and provides data support for subsequent accurate calculations.

[0048] Based on at least three time-series correlation data pairs, combined with pre-calibrated correlation relationships, the dynamic viscosity value of the liquid to be tested is determined. Through collaborative verification of multiple data pairs and calibration of pre-calibrated correlation relationships, measurement deviations caused by factors such as operating condition fluctuations and changes in ambient temperature are offset, thereby improving the accuracy and repeatability of viscosity measurement and adapting to liquids to be tested with different viscosity ranges. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0050] Figure 1 This is a flowchart of a viscosity measurement method provided in an embodiment of this application;

[0051] Figure 2 The following is a logic flowchart for determining the dynamic viscosity value of the liquid to be tested, provided in an embodiment of this application.

[0052] Figure 3This is a structural diagram of a viscosity measuring device provided in an embodiment of this application.

[0053] Reference numerals: 1. Container; 2. Capillary tube; 3. Regulating valve; 4. Guide channel; 5. Magnetic holding mechanism; 6. Magnetic buoy; 7. Detection module. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0055] Example 1:

[0056] like Figure 1 As shown in the figure, a viscosity measurement method is provided in an embodiment of this application. The method includes:

[0057] S1. A negative pressure is established at the top of the container at a constant rate, causing the air pressure inside the container to decrease linearly from atmospheric pressure to the target value. The liquid to be tested is then drawn upward into the container through a capillary tube located at the bottom of the container.

[0058] Specifically, establishing negative pressure includes:

[0059] The real-time air pressure value inside the container and the real-time liquid level rise rate of the liquid to be measured are obtained, and the rate deviation between the real-time liquid level rise rate and the preset liquid level reference slope is calculated.

[0060] The pumping rate of the vacuum pump is adjusted based on the rate deviation to maintain the gas pressure inside the container decreasing linearly from atmospheric pressure to the target value at a constant rate.

[0061] The constant rate characterizes the linear decrease slope of the internal air pressure of the container over time, meaning that the decrease in air pressure per unit time remains constant, providing a constant driving force for the capillary tube at the bottom of the container to draw the liquid to be tested into the container; the constant rate is determined in advance through calibration experiments using a standard viscosity liquid.

[0062] Because different measuring devices have different container volumes and capillary sizes, the viscosity ranges of the liquids to be measured also vary. If a fixed constant rate is preset directly, it will cause the rate to be mismatched with the device hardware parameters and the viscosity characteristics of the liquid to be measured, which will lead to problems such as abnormal capillary liquid absorption rate and liquid surface fluctuations, and will not meet the stability requirements for establishing negative pressure. The constant rate means that the decrease in air pressure in the container remains constant per unit time. Mathematically, it is represented by the first derivative of air pressure with respect to time being a fixed constant, i.e., dp / dt=-C, where p represents the real-time air pressure value inside the container, t represents the real-time time during the negative pressure establishment process, and C is the constant rate. The negative sign indicates the physical trend of the air pressure in the container gradually decreasing over time. This constant rate only reflects the uniformity of the air pressure decrease, and its value is directly related to the strength of the capillary liquid absorption driving force.

[0063] A standard viscosity liquid commonly used in the field of viscosity measurement is selected as the calibration medium. The standard viscosity liquid must cover the conventional viscosity range of the liquid to be tested, and its viscosity value must be calibrated by a national metrology institution to ensure calibration accuracy. A gas pressure sensor installation interface is reserved at the top of the container, and a capillary tube mounting seat is set at the bottom of the container. At the same time, attention should be paid to the influence of the capillary tube material on the adsorption of the liquid. Before the calibration experiment, the container and capillary tube are cleaned to remove residual impurities and moisture to ensure that the measurement environment is free from interference.

[0064] A standard viscosity liquid is placed in a storage tank below the capillary tube. The pumping output power of the vacuum pump is adjusted, and the pressure data inside the container is acquired in real time through a pressure sensor installed on the top of the container. The liquid level change is acquired in real time through a laser liquid level sensor installed on the side wall of the container. The state of the liquid to be tested being drawn into the container through the capillary tube is observed. Pumping parameters with a stable liquid level rise, no impact fluctuations, and no interruption of flow and empty suction are selected, and the constant rate of linear pressure decrease is determined accordingly. Each standard viscosity liquid is calibrated three times. After removing abnormal data, the average value is taken as the constant rate corresponding to that standard viscosity liquid. The constant rate suitable for the viscosity range of the device and the liquid to be tested is determined by combining the calibration results of all standard viscosity liquids.

[0065] For example, after multiple calibration experiments, it was determined that the constant rate adapted to this device is -0.8 kPa / s, that is, the gas pressure inside the container decreases steadily by 0.8 kPa every 1 second. This constant rate is pre-stored to form a fixed reference control parameter for subsequent adjustment of negative pressure establishment.

[0066] This ensures that the constant rate is compatible with the hardware structure of the measuring device and the viscosity characteristics of the liquid being measured, guaranteeing that the benchmark for linear pressure reduction is adaptable to operating conditions and providing a guarantee for the stability of negative pressure establishment.

[0067] If the vacuum pump is directly controlled in an open-loop manner, it is impossible to eliminate the pressure variation deviations caused by factors such as capillary flow resistance fluctuations, differences in the viscosity of the liquid being tested, and slight changes in ambient temperature. This makes it difficult to ensure that the pressure inside the container decreases linearly at a strictly calibrated constant rate, which in turn leads to an uncontrolled rate of liquid level rise, affecting the accuracy of subsequent magnetic buoy descent detection and liquid level rise height calculation. Real-time pressure values ​​are obtained through a pressure sensor installed on the top of the container. The pressure sensor probe extends deep into the container and is sealed to the inner wall to avoid measurement errors caused by pressure leakage, ensuring real-time capture of pressure change details.

[0068] The real-time liquid level rise rate is obtained by a laser level sensor installed on the side wall of the container. The laser emitted by the sensor illuminates the liquid surface perpendicularly, and the real-time liquid level position is calculated by the reflected signal. The controller calculates the real-time liquid level rise rate based on the difference between two adjacent liquid level position acquisitions and the sampling period. The sampling period is consistent with that of the pressure sensor to ensure data synchronization. The preset liquid level reference slope is a liquid level rise reference rate that matches the calibrated constant rate. It is determined based on the constant rate, container volume, and capillary size. It serves as a comparison benchmark for closed-loop regulation and is used to determine whether the real-time liquid level rise rate meets expectations.

[0069] The rate deviation is the difference between the real-time liquid level rise rate and the preset liquid level reference slope. A positive deviation indicates that the real-time liquid level rise rate is too fast, and a negative deviation indicates that the real-time liquid level rise rate is too slow. This deviation is the direct basis for adjusting the vacuum pump's pumping speed. Specifically, after the negative pressure is established and started, the controller sends a control signal to start the vacuum pump and various sensors. The pressure sensor acquires the pressure value inside the container in real time and transmits it to the controller synchronously. The laser liquid level sensor acquires the real-time liquid level position of the liquid to be measured at the same period, transmits it to the controller, and calculates the real-time liquid level rise rate.

[0070] For example, the preset liquid level reference slope matched with the constant rate of -0.8 kPa / s is 0.2 mm / s. The difference between the acquired real-time liquid level rise rate and the reference slope of 0.2 mm / s is calculated to obtain the rate deviation. When the real-time liquid level rise rate is 0.25 mm / s, the rate deviation is +0.05 mm / s. The controller determines that the liquid level rises too fast and reduces the pumping power of the vacuum pump by outputting a control signal, thereby reducing the pumping rate. When the real-time liquid level rise rate is 0.15 mm / s, the rate deviation is -0.05 mm / s. The controller determines that the liquid level rises too slowly and increases the pumping power of the vacuum pump by outputting a control signal, thereby increasing the pumping rate. The pumping rate of the vacuum pump is continuously and dynamically corrected to maintain the air pressure inside the container at a calibrated constant rate, linearly decreasing from the standard atmospheric pressure of 101.3 kPa to the preset target air pressure of 90 kPa. At the same time, the liquid to be measured is smoothly drawn into the container through the capillary tube under the action of constant negative pressure driving force.

[0071] This counteracts pressure fluctuations caused by factors such as capillary flow resistance fluctuations, liquid viscosity differences, and ambient temperature changes, ensuring that the pressure inside the container decreases linearly at a constant rate, thus guaranteeing the stability and consistency of the negative pressure establishment process. It also provides a undisturbed liquid environment for the magnetic buoy's descent, while ensuring the synchronization of the liquid level rise process with the release and descent detection of the magnetic buoy.

[0072] S2. At the instant the negative pressure begins to build up, the magnetic buoy, which is set inside the container and above the liquid to be tested, is released synchronously through the same control signal and falls freely in the guide channel set along the axis of the container.

[0073] Specifically, the free fall process of the magnetic buoy includes:

[0074] At the moment the negative pressure begins to build up, the magnetic buoy, which is set inside the container and above the liquid to be tested, is released synchronously through the same control signal, and the magnetic buoy is restricted to moving only along the axis of the container through the guide channel.

[0075] Using the constant rate of linear decrease in air pressure inside the container as a time reference, the detection signal of the magnetic buoy's descent position is synchronously calibrated.

[0076] The contact time between the magnetic buoy and the liquid to be tested is determined based on the real-time liquid level position, and the descent path after the contact time is determined as the descent detection interval.

[0077] The entire viscosity measurement is based on the timing of negative pressure establishment. If there is a timing deviation between the release of the magnetic buoy and the start of negative pressure, it will directly cause the timing of the buoy's movement to be mismatched with the rise of the liquid level and the change of air pressure. At the same time, the magnetic buoy is prone to non-axial movements such as radial offset and circumferential rotation when it is unrestrained. Such movements will change the form of viscous resistance between the buoy and the liquid, making the descent parameters unable to truly reflect the viscosity characteristics of the liquid being measured. The same control signal refers to the single-channel level trigger signal output by the controller. This signal is simultaneously transmitted to the vacuum pump and the magnetic holding mechanism to ensure the timing consistency between negative pressure establishment and buoy release.

[0078] The outer wall of the magnetic buoy and the inner wall of the guide channel form a clearance fit. The guide channel is a cylindrical cavity arranged along the axis of the container. The inner wall of the channel is smoothed to eliminate additional frictional resistance. The deviation between the axis of the guide channel and the central axis of the container is controlled within a very small range. Structurally, this restricts the buoy to linear displacement along the vertical axis only, prohibiting radial movement and circumferential rotation. The initial placement position of the magnetic buoy is fixed above the initial liquid level of the liquid to be measured inside the container. It is pre-fixed by a positioning bracket. The release mechanism is an electromagnetic attraction structure. After receiving a control signal, the electromagnetic attraction disappears, the positioning bracket is released, and the buoy begins to fall under the action of gravity.

[0079] For example, the magnetic buoy is set to have a diameter of 3mm, a height of 8mm, an inner diameter of 3.2mm for the guide channel, a single-sided gap of 0.1mm between the buoy and the inner wall of the channel, and a vertical distance of 15mm between the initial positioning position of the buoy and the initial liquid surface of the liquid to be measured. The transmission delay of the output trigger signal to the negative pressure vacuum pump and the electromagnetic release mechanism is consistent, ensuring that the negative pressure starts to build up and the buoy release action is executed synchronously.

[0080] This eliminates the timing misalignment problem between buoy release and negative pressure establishment, ensuring that the buoy's movement is consistent with the core timing reference. At the same time, the axial constraint of the guide channel avoids parameter interference caused by the buoy's non-ideal motion state, so that the buoy's descent process is only affected by gravity, liquid buoyancy, and viscous resistance.

[0081] The magnetic sensing element used to detect the descent position of a magnetic buoy has inherent signal transmission delay and sampling response lag. This kind of timing deviation at the hardware level will cause a mismatch between the actual position of the buoy and the time of the detection signal output. The time change corresponding to the calibrated constant rate is used as a unified timestamp. This timestamp is not affected by the hardware characteristics of the sensing element and has timing reference. The timestamp of the buoy position signal obtained by the magnetoresistive sensor is aligned and corrected with the timestamp corresponding to the constant rate for synchronous calibration, eliminating the timing offset caused by the sensor's own response delay.

[0082] The detection element uses a magnetoresistive sensor arranged along the axial direction of the guide channel. The sensor acquires the buoy's magnetic field signal at a fixed period and outputs a position detection signal. When the controller receives the detection signal, it retrieves the timing data corresponding to the constant rate and matches and corrects the actual acquisition time of the detection signal with the theoretical time. For example, if the constant rate is -0.8 kPa / s, the signal sampling period of the magnetoresistive sensor is set to 10 ms, and the sensor's inherent response delay is about 2 ms, the controller will advance the output timing of the detection signal by 2 ms during the calibration process to make it completely aligned with the timestamp corresponding to the constant rate, thus completing the synchronous calibration of the detection signal.

[0083] This eliminates timing deviations caused by the position detection hardware, ensuring that the detection signal for the buoy's descent position has timing accuracy and preventing logical errors in subsequent processing due to timing offsets.

[0084] Before contacting the test liquid, the magnetic buoy undergoes free fall in the gas phase space inside the container. During this stage, the buoy is only affected by gravity and air resistance, and its motion parameters are unrelated to the viscosity of the test liquid, thus representing invalid motion data. The contact time refers to the time from the start of negative pressure when the magnetic buoy falls axially to its lower edge and just contacts the rising surface of the test liquid. This time is determined by the linkage between the buoy position detection signal and the real-time liquid surface position signal. That is, when the real-time liquid surface position is equal to the buoy's falling position, the corresponding time sequence is the contact time. The falling detection interval is the entire motion path of the buoy continuing to fall in the liquid phase after the contact time until the detection position signal is acquired. During this interval, the buoy remains in the test liquid, and its motion is dominated by the viscous resistance of the liquid.

[0085] For example, if the real-time liquid level rise rate of the liquid to be tested is 0.2 mm / s and the initial position of the buoy is 15 mm away from the initial liquid level, the contact time between the buoy and the liquid is calculated and detected in real time to be 75 ms after the negative pressure is started. Taking this contact time as the dividing point, the buoy's falling path before 75 ms is the gas phase ineffective segment, and the buoy's falling path in the liquid phase after 75 ms is the falling detection interval. This interval covers the entire path range between the first detection position and the second detection position on the guide channel.

[0086] This allows for the precise division of effective and ineffective paths, the elimination of motion data unrelated to liquid viscosity, and the retention of only the detection range that reflects the effect of viscous resistance. This provides a boundary basis for determining the effective detection segment and ensures that the subsequent descent time is only related to the viscosity of the liquid being measured, thus providing a foundation for the construction of time-series correlation data pairs.

[0087] S3. During the descent of the magnetic buoy, the time taken for the magnetic buoy to pass through the first and second detection positions on the guide channel is continuously detected to calculate the descent time. At the same time, the real-time liquid level position of the liquid to be tested in the container is detected to obtain the liquid level rise height. These are paired to form a time-series correlation data pair.

[0088] Furthermore, the calculation of the fall time includes:

[0089] Determine the effective detection segment within the descent detection interval between the first and second detection positions on the guide channel;

[0090] Using a constant rate as the timing reference, the acquisition time of the detection signals at the first detection position and the second detection position are time-calibrated respectively.

[0091] The initial descent time is obtained by acquiring the time difference between the first and second detection positions within the effective detection segment after calibration of the magnetic buoy.

[0092] The initial descent time is corrected by combining the real-time liquid level rise rate to obtain the descent time.

[0093] The defined descent detection range is the liquid phase descent path after the magnetic buoy comes into contact with the liquid to be tested. The first and second detection positions on the guide channel may be located outside this descent detection range. The buoy movement in the portion outside this range is in the gas phase invalid segment. If the signal of the entire detection position is used directly to calculate the descent time, invalid data will be introduced, and the calculation result will not reflect the viscosity characteristics of the liquid. The effective detection segment refers to the overlapping part of the first and second detection positions on the guide channel and the descent detection range. That is, only the section of the two detection positions located within the liquid phase descent path of the buoy is retained as the effective range for descent time detection.

[0094] Both the first and second detection positions are composed of magnetoresistive sensors, which are arranged sequentially from top to bottom along the axial direction of the guide channel. The detection range of the sensors is a certain distance above and below their installation position. The controller presets the coordinate parameters of the two detection positions and combines them with the determined boundary coordinates of the fall detection interval. The effective detection segment is selected by comparing the coordinates. At the same time, during the implementation process, the controller retrieves the detection position coordinates and the boundary data of the fall detection interval in real time, automatically completes the determination and selection of the effective detection segment, and only obtains the buoy position signal within the effective detection segment for subsequent time calculation.

[0095] For example, the total length of the guide channel is 80mm. The first detection position is set in the section 30mm to 32mm below the top of the guide channel, and the second detection position is set in the section 50mm to 52mm below the top of the guide channel. The drop detection range is the section 25mm to 75mm below the top of the guide channel, that is, from the position corresponding to the buoy contact time to the detection endpoint. Through coordinate comparison, the effective detection segment of the first detection position is the 30mm to 32mm section, and the effective detection segment of the second detection position is the 50mm to 52mm section. Both effective detection segments are completely within the drop detection range, and the invalid detection part outside the range is eliminated.

[0096] By eliminating invalid portions of the detection location that are outside the fall detection range, the detection signals used to calculate the fall time are ensured to all originate from the buoy's movement within the liquid phase, thus providing accurate data for fall time calculation.

[0097] The magnetoresistive sensors at the first and second detection positions have inherent response delays and transmission delays due to differences in hardware response characteristics and signal transmission paths. Furthermore, the delays of the two sensors may differ. If the original time data of the sensor sampling signals is used to calculate the descent time, it will lead to a deviation in the time difference. Using a constant rate as the timing reference and following the previously calibrated linear pressure descent rate, the corresponding timestamp is not affected by the sensor hardware characteristics. The acquisition time of the detection signal refers to the moment when the sensor acquires the output signal when the buoy passes through the effective detection segment. Timing calibration is to correct the timing offset of the hardware delay by comparing the timestamp with the original signal time of the sensor.

[0098] Specifically, the inherent response delay of the two detection position sensors is determined in advance through experiments, and the delay data is pre-stored in the controller. When the sensor outputs a signal that the buoy has passed through the effective detection section, the controller simultaneously retrieves the timestamp corresponding to the constant rate, subtracts its own inherent delay from the original signal time of the sensor, and obtains the calibrated signal acquisition time, thereby achieving unified alignment of the timing of the two detection position signals.

[0099] For example, the constant rate is -0.8 kPa / s, and the corresponding timestamp is updated synchronously at a 10 ms cycle with the negative pressure start time as 0. The inherent response delay of the first detection position sensor is 2 ms, and the inherent response delay of the second detection position sensor is 2.2 ms. When the first sensor obtains the original signal of the buoy passing through the effective detection section at 120 ms, the calibrated signal acquisition time is 120 ms - 2 ms = 118 ms. When the second sensor obtains the original signal at 180 ms, the calibrated signal acquisition time is 180 ms - 2.2 ms = 177.8 ms, in order to eliminate the delay difference between the two sensors.

[0100] This eliminates the hardware delay and transmission deviation of the two detection position sensors, ensuring that the signal acquisition time of the buoy passing through the two effective detection segments has timing accuracy and consistency, and avoiding errors in the calculation of the descent time due to timing deviation.

[0101] After effective detection segment screening and timing calibration, the signal acquisition time of the two detection positions has achieved accuracy and consistency. By calculating the difference between the two calibrated times, the original time data of the buoy passing through the effective detection segment can be obtained, namely the initial descent time. This time data is the basic parameter reflecting the buoy's speed in the liquid phase and is also the original basis for subsequent dynamic correction. Without calculating the time difference, it is impossible to obtain the motion time parameter that reflects the viscous resistance of the liquid.

[0102] The initial fall time refers to the time interval between the magnetic buoy passing through the first detection position within the effective detection segment and passing through the second detection position within the effective detection segment. That is, the initial fall time = the signal acquisition time after calibration at the second detection position - the signal acquisition time after calibration at the first detection position. The controller retrieves the signal acquisition time after calibration at the two detection positions, performs the difference calculation, obtains the initial fall time data, and stores it.

[0103] For example, after timing calibration, the signal acquisition time at the first detection position is 118ms and the signal acquisition time at the second detection position is 177.8ms. The controller performs the difference calculation: 177.8ms - 118ms = 59.8ms. This 59.8ms is the initial descent time, which reflects the original descent time of the buoy within the effective detection range, without considering the relative motion deviation caused by the rise of the liquid level.

[0104] This provides a clear basis for subsequent dynamic corrections and enables real-time calculation of descent time, ensuring the synchronous progress of motion parameter acquisition and subsequent viscosity measurement processes.

[0105] During the buoy's descent, the liquid to be tested is continuously drawn upward into the container through a capillary tube under negative pressure, resulting in a dynamic rise in the liquid level. A relative motion exists between the buoy and the liquid level. The initial descent time only reflects the absolute motion time of the buoy relative to the guide channel, without considering the relative motion deviation caused by the rising liquid level. This deviation prevents the initial descent time from accurately reflecting the actual motion time of the buoy in the liquid, thus affecting the accuracy of viscosity calculation. The real-time liquid level rise rate, acquired in real-time by the laser level sensor and transmitted to the controller, reflects the real-time dynamic rise of the liquid level. The relative motion time of the buoy corresponding to the distance the liquid level rises during the initial descent time is calculated and added to the initial descent time to obtain the final descent time, reflecting the actual motion time of the buoy in the liquid.

[0106] For example, if the initial descent time is 59.8 ms and the real-time liquid surface rise rate is 0.2 mm / s, the distance the liquid surface rises in 59.8 ms is approximately 0.01196 mm (0.2 mm / s × 0.0598 s ≈ 0.01196 mm). The distance the buoy travels relative to the liquid needs to be added to this liquid surface rise distance. The corresponding relative motion time is 0.01196 mm divided by the buoy's actual descent speed in the liquid (calculated by combining the buoy's weight and buoyancy). After calculation, this relative motion time is 0.2 ms. The corrected descent time is 59.8 ms + 0.2 ms = 60 ms. This time truly reflects the actual descent time of the buoy due to viscous resistance in the liquid.

[0107] This eliminates the relative motion deviation of the buoy caused by the dynamic rise of the liquid level, ensuring that the descent time truly reflects the actual motion state of the buoy in the liquid being tested, accurately reflects the effect of liquid viscous resistance, provides precise time parameters for the construction of time-series correlation data pairs, ensures that the data pairs truly reflect the correlation between liquid viscosity and motion parameters, and provides reliable data support for the subsequent determination of dynamic viscosity values.

[0108] Further, determining the height of the liquid level rise includes:

[0109] At the instant the negative pressure begins to build, the initial liquid level position inside the container is acquired synchronously, and the detection signal of the real-time liquid level position is time-aligned with a constant rate as the time reference.

[0110] By combining the contact time between the magnetic buoy and the liquid to be measured, the real-time liquid level position before and after the contact time is calibrated in segments, and the position difference between the calibrated real-time liquid level position and the initial liquid level position is calculated to obtain the initial liquid level rise height.

[0111] The initial liquid level rise height is dynamically verified based on the real-time liquid level rise rate to obtain the liquid level rise height.

[0112] The calculation of the liquid level rise is based on the initial liquid level position. If the acquisition of the initial liquid level position is not synchronized with the start of negative pressure, it will cause a deviation in the reference position, affecting the accuracy of subsequent height calculations. The liquid level detection sensor has inherent response delay and signal transmission deviation. The initial liquid level position refers to the spatial coordinates of the initial static liquid level of the liquid to be measured in the container at the moment of negative pressure start-up, which is used as the reference zero point for subsequent liquid level rise calculations. The controller sends the same control signal to trigger the liquid level detection sensor to acquire the initial liquid level position at the same time as the negative pressure is established, ensuring that the timing of negative pressure start-up and initial liquid level acquisition is completely consistent.

[0113] Using a constant rate as the timing reference, and following the previously calibrated linear rate of air pressure decrease, the corresponding timestamp is unique and uniform. Timing alignment uses this timestamp to correct the signal response delay of the liquid level detection sensor, ensuring that the detection signal's timing is synchronized with the timing sequence. Specifically, the liquid level detection sensor is a laser liquid level sensor. The sensor probe is fixed to the top of the container, parallel to the container's axis, i.e., vertically downward. The detection light shines perpendicularly onto the liquid surface along the container's axis, ensuring that the laser reflection path coincides with the axis, avoiding positional errors caused by sidewall reflections or angular deviations. At the moment of negative pressure activation, the control signal from the controller is simultaneously transmitted to the vacuum pump and the laser liquid level sensor, immediately acquiring the initial liquid level position and transmitting it to the controller. The vertical distance between the liquid level and the bottom of the container corresponding to this position is stored as the reference zero point.

[0114] For example, at the instant of negative pressure activation, the initial vertical distance between the liquid level sensor and the probe is 90mm. Combined with the effective height of the container (100mm), the initial liquid level position coordinates are calculated to be 10mm above the bottom of the container. This coordinate is the initial liquid level position. The constant rate is -0.8kPa / s, and the corresponding timestamp is updated synchronously at a period of 10ms. The inherent response delay of the laser liquid level sensor is 1.8ms. During the timing alignment process, the real-time liquid level position signal acquired by the sensor is subtracted by 1.8ms to make it completely aligned with the timestamp. For example, if the original signal time of a certain real-time liquid level position acquired by the sensor is 91.8ms, the calibrated timing time is 90ms, which is consistent with the timestamp corresponding to the constant rate.

[0115] This enables the synchronous acquisition of the initial liquid level position and the negative pressure start-up, ensuring the accuracy of the reference zero point for height calculation; it also eliminates the hardware delay and transmission deviation of the liquid level detection sensor, ensuring the timing accuracy of the liquid level position detection signal and avoiding timing misalignment that could lead to errors in subsequent calibration and calculation.

[0116] The moment the magnetic buoy contacts the liquid being measured, it causes a slight disturbance to the liquid surface, resulting in a deviation in the liquid surface position detection data before and after the contact time. If the detection data is not calibrated in segments, it will affect the accuracy of the liquid surface position. The contact time is the previously determined contact time between the buoy and the liquid, that is, the moment when the lower edge of the buoy just touches the liquid surface. Segment calibration means that the real-time liquid surface position detection data is divided into two segments: before contact and after contact, with this contact time as the dividing point. Before contact, the liquid surface is in a stable rising state, and only the inherent deviation of the sensor is corrected. After contact, due to the disturbance caused by the buoy contact, the position deviation caused by the disturbance needs to be additionally corrected to ensure the accuracy of the liquid surface position data.

[0117] The specific method for correcting disturbances is to define a 10ms disturbance correction window starting from the contact time, extract continuous sensor sampling data within the window, calculate the position difference between adjacent sampling points, identify sampling points whose absolute difference value exceeds the threshold corresponding to the real-time liquid level rise rate as disturbance anomalies and remove them, perform 5-point moving average processing on the remaining valid sampling points to eliminate residual fluctuations, and then perform linear fitting in combination with the stable upward trend of the liquid level before contact to finally obtain the disturbance-free real-time liquid level position.

[0118] The initial liquid level rise height refers to the spatial distance difference between the calibrated real-time liquid level position and the initial liquid level position, i.e., initial liquid level rise height = calibrated real-time liquid level position - initial liquid level position; the specific controller pre-stores buoy contact time data, retrieves the calibrated real-time liquid level position signal in real time, and performs segmented calibration with the contact time as the dividing point: before contact, only the time-aligned liquid level position data is used, and no additional correction is required; after contact, the disturbance is corrected and abnormal data of liquid level fluctuation is eliminated.

[0119] For example, the initial liquid level position is 10mm above the bottom of the container, the buoy contact time is timestamp 75ms, the real-time liquid level rise rate is 0.2mm / s, and the laser level sensor sampling period is 1ms. 75ms before contact, the real-time liquid level position after time alignment is 10.01mm, which does not require additional calibration and is directly used as valid data. From 75ms to 85ms is the disturbance correction window after contact. Among the 10 sets of original data, there are sudden increases in data due to disturbances. After differential elimination of outliers, moving average and linear fitting, the real-time liquid level position is calibrated from the original 10.08mm to 10.07mm. The controller performs difference calculation: 10.07mm-10mm=0.07mm. This 0.07mm is the initial liquid level rise height at that time.

[0120] This eliminates surface disturbance errors caused by the buoy contacting the liquid, ensuring the accuracy of real-time surface position data; it provides a basis for subsequent verification, enabling real-time calculation of the surface rise height and ensuring synchronization with the descent time.

[0121] Although the initial liquid level rise height has been calibrated in segments, it may still be affected by factors such as capillary flow resistance fluctuations and slight changes in ambient temperature, resulting in instantaneous abnormal data. Such abnormal data will cause the liquid level rise height to fail to accurately reflect the actual rise state of the liquid. The real-time liquid level rise rate uses the parameters obtained above, that is, the liquid level rise rate obtained in real time by the laser liquid level sensor and calculated by the controller. This data has been adjusted in a closed loop and has stability and reliability, serving as a reference benchmark for dynamic verification.

[0122] The preset reasonable deviation range is determined by combining the inherent measurement accuracy of the laser level sensor, the maximum allowable deviation of capillary flow resistance fluctuation, and the fluctuation range of the liquid level rise rate of the standard viscosity liquid in the calibration experiment. This reasonable deviation range needs to cover the hardware error of the device and the fluctuation of normal operating conditions, while meeting the accuracy requirements of viscosity measurement. In this embodiment, the measurement accuracy of the laser level sensor is ±0.001mm, and the fluctuation of the liquid level rise rate of the standard viscosity liquid in the calibration experiment does not exceed ±2%. Therefore, the preset reasonable deviation range is set to ±3% of the theoretical liquid level rise height to balance measurement accuracy and adaptability to operating conditions.

[0123] The theoretical liquid level rise is calculated by multiplying the real-time liquid level rise rate by time. This theoretical rise is then compared with the initial rise. If the deviation is within a preset reasonable deviation range, the initial rise is considered valid and requires no correction. If the deviation exceeds the preset reasonable deviation range, it is considered abnormal data, and the initial rise is corrected using the theoretical rise to obtain the final rise.

[0124] Specifically, the real-time liquid level rise rate, initial liquid level rise height, and corresponding time are retrieved to calculate the theoretical liquid level rise height, i.e., theoretical liquid level rise height = real-time liquid level rise rate × time from negative pressure start to the current moment. This is then compared and verified with the initial liquid level rise height, and abnormal data is removed and corrected.

[0125] For example, if the real-time liquid level rise rate is 0.2 mm / s and the current timestamp is 150 ms (150 ms after negative pressure is activated), the theoretical liquid level rise height is 0.2 mm / s × 0.15 s = 0.03 mm. The preset reasonable deviation range is ±0.0009 mm, which is ±3% of the theoretical liquid level rise height. The initial liquid level rise height at this moment is 0.0305 mm, and the deviation between the two is +0.0005 mm, which is within the preset reasonable deviation range. Therefore, the initial height is considered valid and is taken as the liquid level rise height. If the initial liquid level rise height at a certain moment is 0.031 mm, and the deviation from the theoretical height of 0.03 mm is +0.001 mm, which exceeds the preset reasonable deviation range, then it is judged as abnormal data, and 0.03 mm is taken as the corrected liquid level rise height.

[0126] This eliminates instantaneous abnormal data caused by capillary flow resistance fluctuations and changes in ambient temperature, corrects deviations in the initial liquid level rise, ensures that the liquid level rise truly reflects the actual rising state of the liquid being tested, and accurately reflects the influence of liquid viscous resistance on the absorption rate; it provides basic data for subsequent determination of dynamic viscosity values, ensuring that the viscosity calculation results truly reflect the viscosity characteristics of the liquid being tested.

[0127] Specifically, the pairings that constitute time-series correlated data pairs include:

[0128] Using a constant rate as the timing reference, the descent time and the height of the liquid surface rise are synchronized twice in time.

[0129] Based on the contact time, the time series is divided into multiple time segments of equal duration. The average descent time and average liquid level rise height of each time series segment are extracted and matched accordingly to form basic correlation data pairs.

[0130] Based on the coupling relationship between the real-time liquid level rise rate and the constant rate, the rationality of the basic correlation data pairs is verified, and the data pairs that pass the verification are used as time-series correlation data pairs.

[0131] Although the descent time and the liquid level rise height have been time-calibrated and verified separately, their detection paths and sensor types are different, resulting in inherent response differences and signal transmission path deviations. This causes micro-time misalignment to occur even though the time references for both parameters are derived from a constant rate. Direct pairing would lead to a mismatch between the descent time and the liquid level rise height under the same time sequence, making it impossible to establish an effective correlation. Secondary time synchronization refers to aligning and correcting the calculated descent time and the verified liquid level rise height using this time reference to ensure that the time stamps of the two parameters are completely consistent.

[0132] The controller pre-stores the timestamps corresponding to the constant rate and retrieves the original timestamps of the descent time and the liquid level rise height in real time. It compares the timestamps with the timestamps of the two types of parameters, corrects minute timing deviations, and ensures that the same timestamp corresponds to a unique descent time and liquid level rise height. For example, if the constant rate is -0.8 kPa / s, the corresponding timestamp is updated synchronously with the negative pressure start time as 0 and a cycle of 10 ms. The original timestamp corresponding to a certain descent time is calculated to be 170 ms, and the original timestamp of the corresponding liquid level rise height is verified to be 170.3 ms, with a timing deviation of 0.3 ms. During the secondary synchronization process, the controller uses the timestamp as a reference to correct the timestamp of the liquid level rise height to 170 ms, which is completely aligned with the timestamp of the descent time, thus achieving timing synchronization of the two types of parameters.

[0133] This eliminates the minute time-series misalignment between the descent time and the liquid level rise height, ensuring that the timing of the two types of parameters is completely homogeneous, avoiding pairing errors caused by timing deviations, and laying a precise timing foundation for subsequent timing segmentation and data pairing.

[0134] The descent time and liquid level rise at a single moment are easily affected by instantaneous disturbances, such as capillary flow resistance fluctuations and minor perturbations in the buoy's attitude. Pairing these two types of parameters at a single moment will generate a large number of invalid or abnormal data pairs, which cannot truly reflect the correlation between liquid viscosity and motion parameters. The contact time follows the previously determined contact time between the buoy and the liquid, that is, the time sequence when the buoy enters the liquid phase. This is used as the starting point for segmentation to ensure that all segments are within the buoy's liquid phase motion range. Using fixed time intervals, the time sequence after the contact time is divided into several continuous and equal-length time periods. The duration of each time sequence segment is set according to the measurement accuracy requirements to ensure that the data within the segment are representative.

[0135] The average fall time refers to the arithmetic mean of all synchronized fall times within each time series segment, and the average liquid level rise height refers to the arithmetic mean of all synchronized liquid level rise heights within each time series segment. By mapping the average fall time and average liquid level rise height of the same time series segment, basic correlation data pairs are formed, and each time series segment corresponds to a set of basic correlation data pairs.

[0136] The controller pre-stores contact time data, sets the duration of time-series segments, and automatically divides the time-series into segments starting from the contact time. It retrieves the descent time and liquid level rise height within each segment in real time, calculates the segment average, and completes the corresponding matching. For example, if the buoy contact time is a timestamp of 75ms, and the time-series segment duration is set to 50ms, then the first segment is 75ms-125ms, the second segment is 125ms-175ms, the third segment is 175ms-225ms, and so on. Within the first segment, there are three sets of synchronized descent time data with an average of 60ms, and three sets of synchronized liquid level rise height data with an average of 0.01mm. Matching the 60ms with the 0.01mm constitutes the first set of basic correlation data pairs. Within the second segment, the average descent time is 61ms, and the average liquid level rise height is 0.02mm, which are matched to form the second set of basic correlation data pairs. This process is repeated for all segments to complete the construction of basic correlation data pairs.

[0137] This ensures the validity of data within the segments and avoids interference from invalid gas phase data; it also makes the basic correlation data pairs representative, initially reflecting the correlation between liquid viscosity and motion parameters, and providing verification objects for subsequent rationality verification.

[0138] Although the basic correlation data pairs have undergone time synchronization and segmented averaging, abnormal data pairs may still appear due to fluctuations in operating conditions. Such abnormal data pairs will lead to deviations in subsequent viscosity calculations. The coupling relationship between the real-time liquid level rise rate and the constant rate means that the real-time liquid level rise rate shows a fixed trend as the constant rate changes. When the constant rate remains unchanged, the real-time liquid level rise rate should be within a stable range. The deviation between the two needs to be controlled within a preset reasonable range, which is the preset reasonable coupling deviation range.

[0139] The preset reasonable coupling deviation range is set by combining the device hardware parameters, calibration experimental data and measurement accuracy requirements. In this embodiment, it is set to ±5% of the standard liquid level rise rate corresponding to the constant rate. Specifically, when the constant rate is -0.8 kPa / s, the corresponding standard liquid level rise rate is 0.2 mm / s. Therefore, the preset reasonable coupling deviation range is 0.2 mm / s ± 0.01 mm / s, that is, between 0.19 mm / s and 0.21 mm / s. This reasonable coupling deviation range covers the rate deviation caused by device hardware errors, calibration fluctuations and normal operating condition fluctuations, and also meets the accuracy requirements of viscosity measurement, which can effectively distinguish between normal data and abnormal data.

[0140] The system determines whether the coupling deviation between the real-time liquid level rise rate and the standard liquid level rise rate corresponding to the constant rate for each basic associated data pair is within a preset reasonable coupling deviation range. If it is within the reasonable coupling deviation range, the basic data pair is considered valid and retained as a time-series associated data pair. If it exceeds the reasonable coupling deviation range, it is determined to be an abnormal data pair and is removed. The controller pre-stores the real-time liquid level rise rate and compares it with the standard liquid level rise rate corresponding to the constant rate. After calculating the coupling deviation, it compares it with the preset reasonable coupling deviation range to complete the rationality verification and select qualified data pairs.

[0141] For example, a constant rate of -0.8 kPa / s corresponds to a standard liquid level rise rate of 0.2 mm / s, with a preset reasonable coupling deviation range of 0.19 mm / s to 0.21 mm / s. A certain set of basic correlation data pairs corresponds to a real-time liquid level rise rate of 0.205 mm / s and a coupling deviation of +0.005 mm / s, which falls within the reasonable coupling deviation range. Therefore, this data pair is considered valid and is used as a time-series correlation data pair. Another set of basic correlation data pairs corresponds to a real-time liquid level rise rate of 0.22 mm / s and a coupling deviation of +0.02 mm / s, which exceeds the reasonable coupling deviation range. This is therefore considered an abnormal data pair and is discarded.

[0142] This effectively eliminates abnormal basic data pairs caused by fluctuations in operating conditions, ensures the reliability and validity of time-series correlated data pairs, and enables the data pairs to truly reflect the correlation between the viscosity of the liquid under test and the motion parameters, providing basic data for the subsequent determination of dynamic viscosity values ​​and ensuring the closed-loop reliability of the entire viscosity measurement process.

[0143] S4. Based on at least three time-series correlation data pairs, determine the dynamic viscosity value of the liquid to be tested through pre-calibrated correlation relationships.

[0144] Furthermore, the pre-defined relationships include:

[0145] Select at least three standard viscosity liquids with different known dynamic viscosities and measure the time series correlation data pairs for the corresponding time series segments;

[0146] Using a constant rate as the time series benchmark, the average descent time and average liquid level rise height in each set of time series correlation data pairs are fitted with the known dynamic viscosity and real-time liquid level rise rate of the corresponding standard viscosity liquid to establish a mapping relationship for different time series segments, which serves as a pre-calibrated correlation relationship.

[0147] One or two standard viscosity liquids cannot cover the conventional viscosity range of the liquid under test, nor can a universal mapping relationship be established. The standard viscosity liquids must be standard media calibrated by national metrology institutions in the field of viscosity measurement, with clear and stable viscosity values. The dynamic viscosity of at least three standard viscosity liquids must cover the conventional viscosity range of the liquid under test to ensure the suitability of the calibration correlation. For each standard viscosity liquid, the complete measurement process described above is followed to complete all steps, including establishing negative pressure, releasing the magnetic buoy, calculating the descent time, determining the liquid level rise height, and pairing time-series correlation data. Finally, time-series correlation data pairs corresponding to each time segment of each standard viscosity liquid are obtained to ensure that the acquisition logic and data type of the calibration data and the measured data are completely consistent.

[0148] Select standard viscosity liquids, determine the known dynamic viscosity value of each standard viscosity liquid, pre-treat the measuring device, clean the container, capillary tube and guide channel, remove residual impurities and water to avoid interfering with the calibration results; for each standard liquid, start the measurement process in sequence, establish negative pressure at a constant rate, release the magnetic float and define the fall detection interval, calculate the fall time and determine the liquid level rise height, complete the pairing of time series correlation data pairs, and extract the time series correlation data pairs corresponding to each time series segment for each standard liquid.

[0149] For example, select standard solution A (known dynamic viscosity 10 mPa). s), Standard solution B (known dynamic viscosity 50 mPa) s), standard solution C (known dynamic viscosity 100 mPa) The viscosity ranges of the three standard viscosity liquids cover the typical viscosity range (5 mPa) of the liquid being tested. s-120mPa For standard solution A, following the above procedure, the float contact time is 75ms, the time segment duration is set to 50ms, and three time segments are divided (75ms-125ms, 125ms-175ms, 175ms-225ms). Each segment corresponds to a set of time-series correlation data pairs (average descent time, average liquid level rise height), which are (60ms, 0.01mm), (61ms, 0.02mm), (62ms, 0.01mm), and (62ms, 0.01mm). 0.03mm); Similarly, the time-series correlation data pairs for each time segment of standard solution B and standard solution C are obtained. The time-series correlation data pairs for the segment corresponding to standard solution B are (70ms, 0.008mm), (71ms, 0.018mm), and (72ms, 0.028mm), and the time-series correlation data pairs for the segment corresponding to standard solution C are (80ms, 0.006mm), (81ms, 0.016mm), and (82ms, 0.026mm).

[0150] This ensures the comprehensiveness and adaptability of the calibration correlation, avoiding the limitations caused by calibration with a single standard solution; it also ensures the homology between calibration data and measured data, providing reliable and effective basic data for subsequent fitting and establishing mapping relationships, and ensuring that the mapping relationships can accurately adapt to actual measurement scenarios.

[0151] The correlation between a single parameter and dynamic viscosity is easily disturbed and cannot fully reflect viscosity characteristics. At the same time, there are subtle differences in the gas pressure driving conditions and buoy motion states corresponding to different time series segments. Multi-parameter fitting refers to correlating and fitting the average descent time and average liquid level rise height in each set of time series correlation data with the known dynamic viscosity and real-time liquid level rise rate of the corresponding standard liquid. The fitting process must follow the inherent logic of each parameter to ensure that the fitting result can reflect the inherent correlation between the four. The fitting method should be linear or nonlinear to ensure feasibility.

[0152] For each time series segment, a mapping relationship is established between the average descent time, average liquid level rise height, known dynamic viscosity, and real-time liquid level rise rate within that segment. Each segment corresponds to a set of mapping rules, which together constitute a pre-calibrated correlation. Specifically, parameter data for each time series segment corresponding to all standard solutions are retrieved, using the timestamp corresponding to the constant rate as a benchmark to ensure the temporal consistency of the data in each segment. For each time series segment, the parameter data of the three standard solutions are correlated and fitted to determine the correspondence rules between parameters within that segment, forming the mapping relationship for that time series segment. The fitting operation for all time series segments is completed sequentially, and the mapping relationships of all segments are summarized as a pre-calibrated correlation relationship for subsequent matching and viscosity calculation of the liquid data to be tested.

[0153] For example, for the first time segment (75ms-125ms), retrieve parameter data for three standard solutions: Standard Solution A (average descent time 60ms, average liquid level rise 0.01mm, known dynamic viscosity 10mPa). s, real-time liquid level rise rate 0.2 mm / s), standard solution B (average falling time 70 ms, average liquid level rise height 0.008 mm, known dynamic viscosity 50 mPa·s, real-time liquid level rise rate 0.18 mm / s), standard solution C (average falling time 80 ms, average liquid level rise height 0.006 mm, known dynamic viscosity 100 mPa·s). (s, real-time liquid level rise rate 0.16 mm / s); perform multi-parameter correlation fitting on this set of data to establish the mapping relationship of this time series segment. That is, within this time series segment, the longer the average descent time, the smaller the average liquid level rise height, and the slower the real-time liquid level rise rate, the larger the corresponding dynamic viscosity value. After fitting, determine the mapping rule of this time series segment and store it. Similarly, fit the mapping relationship of the second (125 ms-175 ms) and the third (175 ms-225 ms) time series segments respectively, summarize the mapping rules of the three segments, and form a pre-calibrated correlation relationship for subsequent viscosity matching of the liquid to be tested.

[0154] This improves the reliability and accuracy of the mapping relationship, avoids the limitations of fitting a single parameter, adapts to the working conditions of each time segment, ensures that the correlation relationship can accurately correspond to the data of each time segment in the actual measurement, provides a reference for matching the liquid data to be tested later, ensures the practicality of the calibration correlation relationship, and provides core support for the closed-loop reliability of the entire viscosity measurement process.

[0155] Specifically, such as Figure 2 As shown, determining the dynamic viscosity of the liquid to be tested includes:

[0156] The average descent time, average liquid level rise height, constant rate and real-time liquid level rise rate of the liquid under test are matched with the pre-calibrated correlation to extract the corresponding initial viscosity value.

[0157] Based on the coupling deviation between the real-time liquid level rise rate and the constant rate during the current measurement process, the initial viscosity value is dynamically corrected.

[0158] The consistency of the corrected initial viscosity value is checked. If the deviation of the viscosity value determined three times in a row is less than the preset deviation threshold, the average viscosity value is taken as the dynamic viscosity value of the liquid to be tested. Otherwise, the dynamic viscosity value is determined again after reconstructing the time-series correlation data pair.

[0159] The pre-calibrated correlation is a multi-parameter mapping relationship established in time series segments. Without parameter matching, it is impossible to obtain a viscosity reference based on the calibration correlation, and there is no clear object for subsequent correction and verification. The pre-calibrated correlation is the aforementioned time series segmented mapping relationship, and this mapping relationship is constructed based on the calibration data of three standard viscosity liquids with known viscosities, forming a continuous viscosity reference interval. Parameter matching and initial viscosity value extraction are implemented using piecewise linear interpolation. When performing parameter matching, the current time series segment of the liquid to be tested is first determined, and then the parameters of the time series segment are compared with the mapping rules of the time series segment in the calibration correlation to find the calibration data that best matches the parameters to be tested. The known dynamic viscosity value corresponding to the calibration data is extracted as the initial viscosity value of the liquid to be tested in that time series segment.

[0160] Specifically, it retrieves parameter data for each time segment of the liquid under test in real time, and simultaneously retrieves the stored pre-calibrated correlation relationships. It compares and matches parameters one by one according to the time segment, using the average descent time and the real-time liquid level rise rate as the core correlation parameters to determine which two sets of standard liquid calibration parameters the parameter under test falls between. Then, based on the known viscosity values ​​of the two sets of standard liquids and the difference ratio of the core correlation parameters, it calculates the initial viscosity value of the liquid under test through linear interpolation, so as to make full use of the three sets of calibration data to form a continuous viscosity range and achieve accurate matching calculation of the parameter under test.

[0161] For example, the parameters for a certain time segment (75ms-125ms) of the liquid to be tested are: average descent time 65ms, average liquid level rise 0.009mm, constant rate -0.8kPa / s, and real-time liquid level rise rate 0.17mm / s. Retrieving the mapping relationship for this time segment, the calibration data for the three standard solutions within this segment are: Standard Solution A (average descent time 60ms, average liquid level rise 0.01mm, constant rate -0.8kPa / s, real-time liquid level rise rate 0.2mm / s, known dynamic viscosity 10mPa). s), Standard solution B (average descent time 70ms, average liquid level rise height 0.008mm, constant rate -0.8kPa / s, real-time liquid level rise rate 0.18mm / s, known dynamic viscosity 50mPa) s), Standard solution C (average descent time 80ms, average liquid level rise height 0.006mm, constant rate -0.8kPa / s, real-time liquid level rise rate 0.16mm / s, known dynamic viscosity 100mPa) (s); After parameter comparison, the average falling time of the test liquid (65ms) falls between that of standard solution A (60ms) and standard solution B (70ms), and the real-time liquid level rise rate (0.17mm / s) falls between that of standard solution B (0.18mm / s) and standard solution C (0.16mm / s). Considering the range distribution of the core related parameters, the overall parameters of the test liquid fall within the parameter range of standard solution A and standard solution B. Using linear interpolation, the average falling time difference between standard solution A and standard solution B is 10ms, the viscosity difference is 40mPa·s, and the difference in average falling time between the test liquid and standard solution A is 5ms, accounting for 50% of the range. Based on this, the initial viscosity value is calculated to be 10mPa. s+(50mPa s-10mPa s)×50%=30mPa Similarly, complete the parameter matching and initial viscosity value extraction for all time segments of the liquid to be tested.

[0162] This ensures the reasonableness of the initial viscosity value reference, avoids deviations caused by cross-segment matching and parameter incompatibility, provides a reference object for subsequent dynamic correction, and achieves accurate extraction of the initial viscosity value of each time segment, ensuring consistency with the calibration logic.

[0163] During parameter matching, although the fit between parameters and calibration is ensured, there is a slight deviation between the coupling state of the real-time liquid level rise rate and the constant rate during the current measurement process and the coupling state during the calibration process. This will lead to a deviation between the initial viscosity value and the actual viscosity of the liquid being measured. At the same time, the generation of coupling deviation is related to operating conditions such as capillary flow resistance fluctuations and slight changes in ambient temperature, which cannot be completely avoided through parameter matching. The coupling relationship between the real-time liquid level rise rate and the constant rate follows the inherent relationship defined above, that is, when the constant rate remains unchanged, the real-time liquid level rise rate should be within a stable range. The coupling deviation between the two refers to the difference between the currently measured real-time liquid level rise rate and the standard liquid level rise rate corresponding to the constant rate. The magnitude and direction of this difference directly reflect the degree of influence of operating condition fluctuations.

[0164] The process involves adjusting the initial viscosity value based on the magnitude and direction of the coupling deviation, combined with pre-calibrated deviation correction rules. If the coupling deviation is positive, meaning the real-time liquid level rise rate is higher than the standard value, the initial viscosity value is appropriately reduced. If the coupling deviation is negative, meaning the real-time liquid level rise rate is lower than the standard value, the initial viscosity value is appropriately increased. The deviation correction rules are pre-set based on calibration data to ensure that the correction logic is consistent with the calibration correlation. Specifically, the coupling deviation between the real-time liquid level rise rate and the constant rate during the current measurement process is calculated in real time. The pre-set deviation correction rules are retrieved, and for the initial viscosity value of each time segment, the correction operation is performed according to the magnitude and direction of the coupling deviation, generating and storing the corrected viscosity value.

[0165] For example, a constant rate of -0.8 kPa / s corresponds to a standard liquid level rise rate of 0.2 mm / s. The preset deviation correction rule is that for every 0.01 mm / s of coupling deviation, the initial viscosity value is adjusted by 5 mPa. s; The initial viscosity of the liquid under test in a certain time segment is 30 mPa. The current measured real-time liquid level rise rate is 0.19 mm / s, and the coupling deviation is -0.01 mm / s (lower than the standard value). According to the deviation correction rule, the initial viscosity value is increased by 5 mPa. The corrected viscosity value is 35 mPa. s; If the initial viscosity value of another time segment is 60 mPa If the current coupling deviation is +0.01 mm / s (higher than the standard value), then the initial viscosity value will be reduced by 5 mPa. The corrected viscosity value is 55 mPa. s, sequentially complete the dynamic correction of the initial viscosity values ​​of all time segments.

[0166] This eliminates deviations caused by factors such as capillary flow resistance fluctuations and changes in ambient temperature, making the corrected viscosity value more closely match the actual viscosity characteristics of the liquid being tested, compensating for the unavoidable influence of operating condition fluctuations during parameter matching, and improving the accuracy of the viscosity value.

[0167] The dynamically corrected viscosity value may exhibit transient anomalies due to sudden changes in operating conditions. A single corrected viscosity value cannot guarantee stability and reliability. Consistency verification involves acquiring the corrected viscosity value three times consecutively, calculating the deviation between the three viscosity values, and comparing it with a preset deviation threshold to determine whether the viscosity value is stable. The preset deviation threshold is a reasonable deviation range pre-set based on measurement accuracy requirements and is determined according to the device hardware accuracy and calibration accuracy. The verification logic is as follows: if the deviation between the three consecutive corrected viscosity values ​​is less than the preset deviation threshold, it indicates that the viscosity value is stable, and the average of the three values ​​is taken as the final dynamic viscosity value. If the deviation exceeds the preset deviation threshold, it indicates that there is a transient anomaly, and the time-series correlation data pair needs to be reconstructed, and the entire viscosity value determination process needs to be repeated until the verification is successful.

[0168] Specifically, the corrected viscosity value is obtained three times consecutively, the deviation between adjacent values ​​is calculated, and the deviation is compared with a preset deviation threshold to perform a verification judgment. If the verification is qualified, the average of the three values ​​is calculated and stored as the final dynamic viscosity value of the liquid to be tested. If the verification is unqualified, the controller sends a control signal to re-execute the time-series correlation data pair construction step, and then repeats the parameter matching, dynamic correction and consistency verification process in sequence until a qualified viscosity value is obtained.

[0169] For example, the preset deviation threshold is ±2mPa. s, the viscosity values of the liquid to be measured after three consecutive corrections in a certain time sequence segment are 34 mPa s, 35 mPa s, 36 mPa s. The deviation between the three values is 1 mPa s, which is less than the preset deviation threshold. It is determined that the calibration is qualified, and the average value of the three, 35 mPa s, is taken as the final viscosity value of this time sequence segment; if the viscosity values after three consecutive corrections are 34 mPa s, 37 mPa s, 33 mPa s, and the deviation exceeds the preset deviation threshold, it is determined that the calibration is unqualified. The controller starts the re-acquisition process. After reconstituting the time sequence correlation data pair, all steps of determining the dynamic viscosity value are repeated.

[0170] Thus, abnormal viscosity values caused by instantaneous working condition mutations are eliminated, ensuring the stability and reliability of the final dynamic viscosity value. At the same time, the repeatability of the measurement results is achieved, meeting the accuracy requirements of viscosity measurement, avoiding measurement deviations caused by single data; ensuring that the output viscosity value meets the accuracy requirements, avoiding the output of unqualified data, improving the closed-loop logic of the entire viscosity measurement, and ensuring the integrity and rigor of the process.

[0171] [[ID=​​​​​​​​​​​​​The vacuum pump has a rated pumping speed of 10 L / min and is sealed to the top of container 1 via a pipeline. The regulating valve 3 is an electric proportional regulating valve connected in series in the pipeline between the vacuum pump and container 1. The regulating valve 3 can receive control signals from the processing module and precisely control the pumping flow by adjusting the valve core opening, so that the gas pressure in container 1 decreases linearly at a constant rate. The constant rate is preset and output by the processing module according to the aforementioned calibration results. After assembly, the capillary tube 2 at the bottom of container 1 is connected to the liquid sample storage part, and the entire pipeline and container 1 cavity are sealed to prevent negative pressure leakage. For example, the processing module presets the constant negative pressure rate to -0.8 kPa / s. The regulating valve 3 adjusts its opening in real time according to this parameter, so that the gas pressure in container 1 decreases smoothly and linearly from the standard atmospheric pressure of 101.3 kPa to the preset target value of 90 kPa. Under the drive of this constant negative pressure, the liquid to be tested is uniformly drawn upward into the container 1 through the capillary tube 2, and there is no impact or interruption in the liquid level rise process.

[0176] This allows for the establishment of a constant rate of negative pressure within the container and linear pressure reduction, providing uniform and stable absorption conditions for the liquid to be tested. It avoids violent disturbances of the liquid surface from interfering with the subsequent movement of the buoy. At the same time, the sealed structural design ensures the stability of the negative pressure establishment and prevents external gas from seeping in and causing parameter deviations.

[0177] The falling module includes a magnetic float 6 disposed inside the container 1 and above the liquid to be tested, a magnetic holding mechanism 5 for adsorbing and holding the magnetic float 6, and a guide channel 4 disposed along the axis of the container 1.

[0178] The magnetic buoy 6 is released simultaneously with the start of the vacuum pump using the same control signal, allowing it to fall freely in the guide channel 4.

[0179] The above viscosity measurement method requires the magnetic float 6 to be released synchronously with the negative pressure start-up, and to fall freely axially only along the axis of container 1. Existing float-type measuring devices mostly use mechanical snap-on release or have no guide structure, which have problems such as release timing deviation, radial offset and circumferential rotation of the float, and cannot guarantee the uniqueness of the float's movement trajectory. The magnetic attraction holding mechanism 5 is an electromagnetic attraction structure, which is fixedly installed at the center of the top of the container 1 cavity. When energized, it generates electromagnetic attraction to attract the magnetic float 6. When de-energized, the attraction disappears and the magnetic float 6 is released. The magnetic attraction holding mechanism 5 shares the same control signal source with the vacuum pump, ensuring that the electromagnetic attraction disappears synchronously when the vacuum pump starts. The initial position of the magnetic float 6 is attracted and fixed by the magnetic attraction holding mechanism 5 above the initial liquid surface of the liquid to be measured inside the container 1, with a vertical spacing of 15mm, in a constant temperature and sealed environment.

[0180] The guide channel 4 is a cylindrical cavity coaxially arranged along the axis of container 1. The inner wall is polished to reduce frictional resistance. The upper and lower ends of the channel are unobstructed and are connected to the cavity of container 1. The outer wall of the magnetic buoy 6 forms a 0.1mm single-sided gap with the inner wall of the guide channel 4, allowing the magnetic buoy 6 to only make linear displacement along the vertical axis and restricting radial movement and circumferential rotation. The control signal is the level signal output by the processing module, which is synchronously transmitted to the vacuum pump and the magnetic holding mechanism 5 to realize the timing synchronization of negative pressure start-up and buoy release. For example, the attraction force of the magnetic holding mechanism 5 is set to 2N to stably attract the magnetic buoy 6. After the power is cut off, the attraction force disappears instantly, and the magnetic buoy 6 falls vertically along the guide channel 4 under the action of gravity without trajectory deviation or attitude flipping.

[0181] This eliminates the timing deviation between buoy release and negative pressure activation. The axial constraint of the guide channel 4 ensures that the buoy's descent is only affected by gravity, liquid buoyancy, and viscous resistance, laying a structural foundation for accurate detection of descent time. This allows the detection module 7 to accurately capture the buoy's motion signal, avoiding signal loss or error due to buoy deviation. At the same time, the contact timing between the magnetic buoy 6 and the liquid to be tested can be accurately determined, providing a timing boundary for the segmented detection and data verification of the detection module 7 and the processing module.

[0182] The detection module 7 includes a first sensor group arranged coaxially along the guide channel 4 and a second sensor group set on the top of the container 1. The first sensor group is used to detect the falling time of the magnetic buoy 6 at different detection positions, and the second sensor group is used to detect the rise height of the liquid surface of the liquid to be tested.

[0183] The above method requires simultaneous detection of the buoy's descent time and the liquid level rise height, and the construction of a time-series correlation data pair. Existing devices mostly use a single sensor to detect a single parameter, which cannot achieve simultaneous acquisition of two parameters in time, and are easily affected by ambient light interference, resulting in insufficient detection accuracy. The first sensing group is a magnetoresistive sensor, with two sets of detection probes arranged coaxially along the guide channel 4, corresponding to the first detection position and the second detection position, respectively. The sensor probes are embedded in the inner wall of the guide channel 4. When the magnetic buoy 6 passes through the detection position, the change in the magnetic field distribution triggers a jump in the magnetoresistive resistance value, and the sensor outputs a level jump signal to record the time when the buoy passes through. The vertical distance between the two sets of probes is 20mm. The first detection position is 30mm from the top of the guide channel 4, and the second detection position is 50mm from the top of the guide channel 4, both of which are within the buoy descent detection range.

[0184] The second sensing group is a laser displacement sensor, fixedly installed on the top of container 1. It emits a laser to the surface of the liquid to be measured and calculates the real-time liquid surface position based on the laser's time of flight. The sampling period of both sensing groups is set to 10ms, and both are synchronized with a constant rate as the timing reference. The output detection signals are synchronously transmitted to the processing module. For example, when the magnetic buoy 6 passes the first detection position, the first sensing group outputs a low-level transition signal, marked as 118ms; when it passes the second detection position, it outputs another transition signal, marked as 177.8ms. The time difference between the two signals is the descent time. The second sensing group acquires the liquid surface displacement in real time and calculates the difference between it and the initial liquid surface position to obtain the liquid surface rise height.

[0185] This enables the synchronous acquisition of descent time and liquid level rise height without detection timing deviation; improves the stability and accuracy of detection signals, and outputs timing correlation data that meets the requirements; accurately detects signals to avoid data distortion, and enables the calibration relationship matching, dynamic correction and consistency verification of the processing module to be effectively executed.

[0186] The processing module determines the dynamic viscosity value of the liquid to be tested based on the time-series correlation data output by the first and second sensor groups through a pre-calibrated correlation relationship.

[0187] The aforementioned viscosity measurement method includes multiple data processing steps such as timing calibration, data pairing, calibration relationship matching, dynamic correction, and consistency verification. Manual processing cannot achieve precise timing control and rapid data calculation, and is prone to introducing human error. The processing module uses an industrial-grade PLC controller as its core hardware, integrating a data sampling unit, a storage unit, and a computing unit. The data sampling unit receives the detection signals from the first and second sensor groups and completes the signal timing calibration. The storage unit contains pre-calibrated segmented mapping relationship data, as well as preset parameters such as deviation thresholds and deviation correction rules. The computing unit, according to the aforementioned method logic, sequentially executes the calculation of the descent time, determination of the liquid level rise height, pairing of timing-related data, extraction of initial viscosity, dynamic correction, and consistency verification.

[0188] The processing module simultaneously outputs control signals to the regulating valve 3 of the suction module and the magnetic holding mechanism 5 of the descent module to achieve unified control of negative pressure regulation and buoy release. For example, after receiving the detection signal, the processing module completes the second synchronization of the timing sequence at a constant rate, divides the timing sequence into segments of 50ms, extracts the average descent time and average liquid level rise height of each segment to construct basic data pairs, matches the qualified data pairs with the calibration mapping relationship after rationality verification, extracts the initial viscosity value, and then completes the correction based on the coupling deviation between the real-time liquid level rise rate and the constant rate. After three consecutive verifications of the deviation being qualified, the average value is calculated to obtain the dynamic viscosity value.

[0189] This enables the automated operation of the entire viscosity measurement process without manual intervention; it effectively eliminates abnormal data and corrects operating condition deviations, ensuring the stability and repeatability of viscosity calculation results; it provides output data for viscosity measurement, while the processing module stores multiple sets of calibration data and measurement results, supporting repeated measurements and ensuring the continuous and stable use of the device. If the consistency verification fails, the processing module can automatically issue instructions to restart the detection and data processing process until a qualified viscosity value is output.

[0190] Since the principle of the device in this application embodiment for solving the problem is similar to the method described above in this application embodiment, the implementation of the device is the same as the implementation of the method, and the repeated parts will not be described again.

Claims

1. A method of viscosity measurement, characterized by, include: A negative pressure is established at the top of the container at a constant rate, causing the air pressure inside the container to decrease linearly from atmospheric pressure to the target value. The liquid to be tested is then drawn upward into the container through a capillary tube located at the bottom of the container. The establishment of negative pressure includes: The real-time air pressure value inside the container and the real-time liquid level rise rate of the liquid to be measured are obtained, and the rate deviation between the real-time liquid level rise rate and the preset liquid level reference slope is calculated. The pumping rate of the vacuum pump is adjusted based on the rate deviation to maintain the gas pressure inside the container decreasing linearly from atmospheric pressure to the target value at the constant rate. At the instant the negative pressure begins to build, a magnetic buoy located inside the container and above the liquid to be tested is released synchronously via the same control signal and falls freely in the guide channel set along the axis of the container. During the descent of the magnetic buoy, the time it takes for the magnetic buoy to pass through the first and second detection positions on the guide channel is continuously detected to calculate the descent time. At the same time, the real-time liquid level position of the liquid to be tested in the container is detected to obtain the liquid level rise height. These are paired to form a time-series correlation data pair. Based on at least three time-series correlation data pairs, the dynamic viscosity value of the liquid to be tested is determined through a pre-calibrated correlation relationship.

2. A method of measuring viscosity as claimed in claim 1, wherein, The constant rate characterizes the linear decrease slope of the internal air pressure of the container over time, that is, the decrease in air pressure per unit time remains constant, and is used to provide a constant driving force for the capillary tube at the bottom of the container to draw the liquid to be tested into the container; the constant rate is determined in advance through calibration experiments using a standard viscosity liquid.

3. A method of measuring viscosity as claimed in claim 1, wherein, The free fall process of the magnetic buoy includes: At the instant the negative pressure begins to build, a magnetic buoy placed inside the container and above the liquid to be tested is released synchronously via the same control signal, and the magnetic buoy is restricted to displacement along the container axis only via a guide channel; Using the constant rate of linear decrease in air pressure inside the container as a timing reference, the detection signal of the magnetic buoy's descent position is synchronously calibrated. The contact time between the magnetic buoy and the liquid to be tested is determined based on the real-time liquid level position, and the descent path after the contact time is determined as the descent detection interval.

4. A method of measuring viscosity as claimed in claim 3 wherein, The calculation of the fall time includes: Determine the effective detection segment within the fall detection interval for the first and second detection positions on the guide channel; Using the constant rate as a timing reference, the acquisition time of the detection signals at the first detection position and the second detection position are respectively time-calibrated. The initial descent time is obtained by acquiring the time difference between the first and second detection positions within the effective detection segment after calibration of the magnetic buoy. The initial descent time is corrected by combining the real-time liquid level rise rate to obtain the descent time.

5. A method of measuring viscosity as claimed in claim 4 wherein, Determining the height of the liquid level rise includes: At the instant the negative pressure begins to build, the initial liquid level position inside the container is acquired synchronously, and the detection signal of the real-time liquid level position is time-aligned using the constant rate as the timing reference. By combining the contact time between the magnetic buoy and the liquid to be measured, the real-time liquid surface position before and after the contact time is calibrated in segments, and the position difference between the calibrated real-time liquid surface position and the initial liquid surface position is calculated to obtain the initial liquid surface rise height. The initial liquid level rise height is dynamically verified based on the real-time liquid level rise rate to obtain the liquid level rise height.

6. A method of measuring viscosity as claimed in claim 5 wherein, The pairing constitutes a time-series associated data pair, including: Using the constant rate as a timing reference, the descent time and the liquid level rise height are synchronized twice in a timing sequence. Based on the contact time, the time sequence is divided into multiple time segments of equal duration. The average descent time and average liquid level rise height of each time segment are extracted and matched accordingly to form basic correlation data pairs. Based on the coupling relationship between the real-time liquid level rise rate and the constant rate, the rationality of the basic correlation data pairs is verified, and the data pairs that pass the verification are used as time-series correlation data pairs.

7. A method of measuring viscosity as claimed in claim 6 wherein, The pre-defined associations include: Select at least three standard viscosity liquids with different known dynamic viscosities and measure the time series correlation data pairs for the corresponding time series segments; Using the constant rate as the time series reference, the average descent time and average liquid level rise height in each set of time series correlation data pairs are fitted with the known dynamic viscosity and real-time liquid level rise rate of the corresponding standard viscosity liquid to establish a mapping relationship for different time series segments, which serves as a pre-calibrated correlation relationship.

8. A method of measuring viscosity as claimed in claim 7, wherein, Determining the dynamic viscosity value of the liquid to be tested includes: The average descent time, average liquid level rise height, constant rate and real-time liquid level rise rate of the liquid under test are matched with the pre-calibrated correlation to extract the corresponding initial viscosity value. Based on the coupling deviation between the real-time liquid level rise rate and the constant rate during the current measurement process, the initial viscosity value is dynamically corrected. The initial viscosity value after correction is checked for consistency. If the deviation of the viscosity value determined three times in a row is less than the preset deviation threshold, the average viscosity value is taken as the dynamic viscosity value of the liquid to be tested. Otherwise, the dynamic viscosity value is determined again after reconstructing the time-series correlation data pair.

9. A viscosity measuring device for carrying out a viscosity measuring method according to any one of claims 1 to 8, characterized in that include: The suction module includes a container, a capillary tube disposed at the bottom of the container, and a vacuum pump connected to the top of the container via a regulating valve. The regulating valve is used to establish a negative pressure in the container at a constant rate, so that the liquid to be tested is sucked upward through the capillary tube. The falling module includes a magnetic buoy disposed inside the container and above the liquid to be tested, a magnetic holding mechanism for adsorbing and holding the magnetic buoy, and a guide channel disposed along the axis of the container. The magnetic buoy is released simultaneously with the start of the vacuum pump by the same control signal, allowing it to fall freely in the guide channel. The detection module includes a first sensor group arranged vertically along the guide channel and a second sensor group disposed on the side wall of the container. The first sensor group is used to detect the falling time of the magnetic buoy at different detection positions, and the second sensor group is used to detect the rise height of the liquid surface of the liquid to be tested. The processing module determines the dynamic viscosity value of the liquid under test based on the time-series correlation data output by the first and second sensor groups through a pre-calibrated correlation relationship.

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