Online mud layer interface measurement algorithm

Abstract

The invention belongs to the technical field of iron separation production, and particularly relates to an online mud layer interface measurement algorithm which comprises the following steps: S1, calculating layered reference conductivity including clear liquid layer reference conductivity, settling layer reference conductivity and mud layer reference conductivity; s2, judging whether a difference value between the reference conductivity of the clear liquid layer and the reference conductivity of the settling layer is greater than 2 or not so as to judge whether a mud layer and the settling layer exist in the settling tank or not, and calculating the position of the mud layer; s3, after the mud layer is calculated through the conductivity, the mud layer is calculated through pressure in an auxiliary mode, and the auxiliary measurement logic is as follows: when the first buoyancy becomes large, it is judged that clear liquid is entered; if the buoyancy increases for the second time and continuously increases, it is judged that the water enters the settling layer; after the buoyancy change is stable for the second time, entering the mud layer is judged. The invention can solve the problems that the conductivity basic value is small, the change fluctuation of different working conditions is large, and the boundary layer cannot be distinguished through the simple absolute value of the conductivity and the increase and decrease of the conductivity when the conductivity is measured by an online mud layer interface measuring device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of iron ore dressing, and particularly relates to an online mud layer interface measurement algorithm. BACKGROUND

[0002] The metallurgical industry is a basic industry and a raw material source for the manufacturing industry, the automobile industry and civil engineering. The iron ore dressing industry is an important part of the metallurgical industry. In the iron ore dressing production process, the settling tank and the thickening tank are the most important part of the production process. In the process of the settling tank and the thickening tank, the settling effect of the material medium is related to the efficiency of the whole process and the quality and yield of the subsequent production. In the existing production process, the height of the medium in the tank is mainly measured manually, which is poor in timeliness and has large errors, resulting in poor control effect of the flocculating agent in the production process and easy occurrence of running mud, thereby reducing the efficiency of the whole production process. Moreover, the surface temperature of the production tank body reaches 70 DEG C in summer, which is a great burden on the workers.

[0003] The existing density boundary detection equipment and ultrasonic sludge detection equipment cannot adapt to high temperature or high alkalinity in the production process. The existing contact type mud layer interface instrument cannot distinguish the settling layer (mixed layer) and has defects such as complex maintenance means and high cost. Through experimental methods, it is found that the conductivity of the alkali solution in the iron ore dressing industry is relatively stable, and the conductivity of the mixed liquid changes obviously after the mixed metal particle material. Therefore, the conductivity of different heights of the settling tank is measured by the conductivity detection device, and an algorithm is designed to measure the layering of the iron ore settling tank. At the same time, due to the great difference between the liquid density in the settling tank and the mud layer density, the buoyancy of the same object in different media is different, and the position of the settling layer is calculated by the buoyancy.

[0004] When the online mud layer interface measurement device is used to measure the conductivity, the step motor is driven by the PLC to rotate the winch, and the proximity switch and the limit switch are matched to control the conductivity sensor to ascend and descend on the measured material tank. Because the material clear liquid and the mud layer have different densities, the buoyancy of the sensor probe generated by the material clear liquid and the mud layer is also different. In order to measure the buoyancy, the sensor wire is installed on the pulley support at the measurement point of the measured material, and the pressure sensor is installed on the pulley support point, so as to judge the buoyancy of the material to the sensor probe through the size of the pressure.

[0005] The data of the pressure sensor and the conductivity sensor are transmitted to the PLC in real time, and the PLC stores the real-time data in the fixed register address. In order to facilitate user operation and data recording, the upper computer is installed, the upper computer is linked with the PLC through the RJ45, and the communication protocol is ModBus. The PLC is internally provided with five working states of ready, measurement, reset, fault and stop, and the working state is set through the knob switch, the emergency stop switch, the probe position, the measurement signal and the fault trigger logic.

[0006] The host computer sends a start measurement signal to the PLC by reading the signal data of the external detection device such as the limit switch of the PLC or by the internal timer. After the PLC receives the start measurement signal sent by the host computer, the working state is set to "measurement", at this time the host computer starts to read the register data of the conductivity and pressure and stores it in the database of the host computer. When the probe position reaches the set measurement range, the PLC starts to recover the probe and controls the cleaning module to clean the probe, and at the same time changes the working state from measurement to "reset". At this time, the host computer stops reading data after reading the end of the measurement state, and starts to calculate.

[0007] The conductivity measured by the "online mud layer interface measuring device" has a small basic value, large fluctuation in different working conditions, and cannot distinguish the boundary layer through simple conductivity absolute value and increase and decrease, and needs a more detailed algorithm. Therefore, the application provides an online mud layer interface measurement algorithm.

[0008] The information disclosed in this background section is only intended to increase the understanding of the general background of the application, and should not be considered as acknowledging or implying in any form that this information constitutes prior art known to those skilled in the art. SUMMARY

[0009] The purpose of the application is to provide an online mud layer interface measurement algorithm to solve the problem of small conductivity basic value, large fluctuation in different working conditions, and inability to distinguish the boundary layer through simple conductivity absolute value and increase and decrease through the "online mud layer interface measuring device".

[0010] In order to achieve the above-mentioned purpose, the application provides the following technical scheme: An online mud layer interface measurement algorithm, comprising the following steps: S1, calculating the layered reference conductivity, including: clear liquid layer reference conductivity, sedimentation layer reference conductivity and mud layer reference conductivity; S2, judging whether the difference between the clear liquid layer reference conductivity and the sedimentation layer reference conductivity is greater than 2, so as to judge whether there is a mud layer and a sedimentation layer in the sedimentation tank, and calculate the position of the mud layer; S3, after the conductivity calculation of the mud layer is completed, the pressure is used to calculate the mud layer: the auxiliary measurement logic is as follows: When the buoyancy increases for the first time, it is judged to enter the clear liquid; The second buoyancy increases and continues to increase, and it is judged to enter the sedimentation layer; After the second buoyancy changes stably, it is judged to enter the mud layer.

[0011] As preferred, before calculating the stratified reference conductivity, the conductivity measuring probe and the pressure sensor are controlled to dive by PLC controlling the stepper motor or servo motor, and the measured position data and the conductivity and pressure data corresponding to the position are stored in the database.

[0012] As preferred, the stratified reference conductivity is calculated in S1, specifically comprising: The point with the minimum position data and the conductivity greater than the conductivity in the air in the database is taken to calculate the position of the data point, and the position is determined as the liquid level position; The average value of the conductivities of all data points between the point with the position at 10 cm above the liquid level position and the point with the maximum conductivity in the database is calculated, and the calculated data is set as the reference conductivity of the supernatant layer; The average value of the conductivities of the two position points is calculated, and the calculated data is set as the reference conductivity of the supernatant layer; The average value of the conductivities of all data points between the point with the maximum position and the point with the position reduced by 10 cm from the position of the point is calculated, and the calculated data is set as the reference conductivity of the mud layer.

[0013] As preferred, the mud layer position is calculated in S2, specifically as follows: If the “reference conductivity of the supernatant layer” is greater than 2, then: The supernatant height = “the installation height of the equipment” - “the liquid level position” The supernatant height = “the installation height of the equipment” - “the liquid level position” The supernatant height = “the installation height of the equipment” - “the liquid level position” If the “reference conductivity of the supernatant layer” is greater than 2, then: The supernatant height = “the installation height of the equipment” - “the liquid level position” The supernatant height = “the installation height of the equipment” - “the liquid level position” The supernatant height = “the installation height of the equipment” - “the liquid level position” If the “reference conductivity of the supernatant layer” is greater than 2, then: The supernatant height = “the installation height of the equipment” - “the liquid level position” The supernatant height = “the installation height of the equipment” - “the liquid level position” The mud layer height = 0 If ('installation height' - settlement layer stratification point) > 10cm, and'mud layer reference conductivity' < ('settlement layer reference conductivity' - 2), take the point with the smallest position in the data set greater than'settlement layer stratification point', conductivity <= ('settlement layer reference conductivity' - 2) as A n After this point, there are three non-decreasing trend points in succession, take the first point of the three points as the demarcation point of the settlement layer and the mud layer, then: The clear liquid height = 'liquid level position' -'settlement layer stratification point' The settlement layer height ='settlement layer stratification point' -'mud layer stratification point' The mud layer height = 'equipment installation height' -'mud layer stratification point' If A n After this point, there are three non-decreasing trend points in succession, take the first point of the three points as the demarcation point of the settlement layer and the mud layer, then: The clear liquid height = 'liquid level position' -'settlement layer stratification point' The settlement layer height ='settlement layer stratification point' -'mud layer stratification point' The mud layer height = 0.

[0014] As preferred, the mud layer is calculated by auxiliary pressure in S3, as follows: Record the position point of the first buoyancy change compared with the liquid level position, if the error is not more than 20cm, take the position point calculated by conductivity as the liquid level position; if the error exceeds 20cm, take the position point of the buoyancy change as the liquid level position; Record the point of the second buoyancy change, compare with the settlement layer stratification point, if the error is not more than 20cm, take the position point calculated by conductivity as the settlement layer stratification point; if the error exceeds 20cm, take the position point of the buoyancy change as the settlement layer stratification point; Record the point of the second buoyancy change, compare with the settlement layer stratification point, if the error is not more than 20cm, take the position point calculated by conductivity as the settlement layer stratification point; if the error exceeds 20cm, take the position point of the buoyancy change as the settlement layer stratification point.

[0015] Compared with the prior art, the present application has the following beneficial effects: the online mud layer interface measurement algorithm of the present application can accurately distinguish the demarcation positions of the liquid level, the settlement layer (mixed layer) and the mud layer, and can still accurately measure even if the concentration of the material in the settling tank changes, and can filter the measurement error caused by the shaking of the material flow in the settling tank. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the corresponding trend graph of conductivity B and inductor position; Figure 2 is the corresponding trend graph of pressure C and inductor position; Figure 3 is a layered reference conductivity calculation flowchart; Figure 4 is a mud layer calculation flowchart; Figure 5 is a pressure auxiliary calculation flowchart. DETAILED DESCRIPTION

[0017] The technical solutions of the patent will be described below in a clear and complete manner. Obviously, the described embodiments are part of the embodiments of the patent, rather than all the embodiments. Based on the embodiments in the patent, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the patent.

[0018] In the description of the patent, it should be noted that the orientations or positional relationships indicated by terms such as “center”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the patent and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the patent.

[0019] In the description of the patent, it should be noted that, unless otherwise explicitly specified and limited, terms such as “mounting”, “connection”, “connection” should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the connection inside two elements. For those skilled in the art, the specific meaning of the above terms in the patent can be understood according to the specific circumstances.

[0020] The conductivity change data sample measured by the online mud layer interface measuring device in the iron separation industry is shown in the following table: Figure 1 The measured data is the conductivity at different positions, and the sampling height interval of the data can be adjusted by modifying the measurement speed of the device. By obtaining the conductivity at different positions, the following rules are found: 1. Weak conductivity exists in the air due to alkali gas, and the conductivity of the clear liquid is strong; 2. When the alkali solution mixed with iron powder enters the settling layer, the conductivity decreases, and the higher the mixing concentration, the lower the conductivity; 3. When it enters the mud layer, the iron content is stable, and the conductivity no longer decreases and tends to be stable.

[0021] Through the above rule changes, the algorithm can be determined as follows: Downward trend point: the conductivity at this position is less than the conductivity at the adjacent previous position. Non-descending trend point: The conductivity of this point is greater than or equal to the conductivity of the previous point adjacent to this point.

[0022] Reference Appendix Figure 1 The graph shows the correlation between conductivity B and sensor position; (attached) Figure 2 This is a trend graph showing the relationship between pressure value C and sensor position.

[0023] In this embodiment, a PLC-controlled stepper motor or servo motor is used to control a conductivity measuring probe for submersion measurement via a mechanical device. This process requires ensuring the precision of the motor's control over the mechanical device to guarantee the accuracy of the measurement data. A pressure sensing device is installed on the fixed structure of the motor and probe. Because the weight of the conductor is fixed, the pressure steadily increases as the probe moves downwards during the measurement process. Upon contact with the liquid, the buoyancy of the liquid causes the conductor to become lighter, resulting in a decrease in the pressure measured by the pressure sensor. This allows for the reverse calculation of buoyancy.

[0024] The density of the mud layer in the settling tank is greater than that of the clear liquid. When the probe enters the settling layer, the concentration and density of the material increase as it gets closer to the mud layer, resulting in higher buoyancy. Once the probe enters the mud layer, the material concentration and buoyancy stabilize.

[0025] The conductivity probe needs real-time feedback capability, and the motor requires stable control by a PLC. The measurement process is controlled by the PLC, which also needs to provide feedback on the "measurement" status to the algorithm to ensure that the captured data can be used for algorithm calculations. When the PLC returns the device's operating status as "measurement," the real-time position and conductivity of the motor are read every 0.5 seconds and recorded in the database. When the PLC returns the device's operating status as non-measurement, data acquisition ends, and calculation begins.

[0026] The online mud interface measurement algorithm of the present invention includes the following steps: Step 1: Calculate the layered reference conductivity, refer to the attached... Figure 3 ; Once the equipment finishes measuring, it begins calculations, and the measurement data is stored in the database. Each set of measurement data includes two points, A and B. A is the probe's diving distance (position), B is the conductivity at that position, and C is the pressure data at that point. Given fixed parameter 1: the equipment installation height, which is also the distance measured by the probe; Given a fixed parameter 2: electrical conductivity in air; Parameter 3: Liquid level; The point in the database with the lowest conductivity (greater than that in air) and the smallest location data is selected. The location of this data point is calculated and determined as the liquid surface location. Parameter 4: Reference conductivity of the clear liquid layer; Take the point in the database where the position is 10 cm above the liquid level position and the point where the conductivity is the largest, and calculate the average conductivity of all data points between the two points; Set the data obtained by calculation as the reference conductivity of the clear liquid layer; Parameter 5: Reference conductivity of the sedimentation layer; Take the point with the largest position in the database and the point with the largest conductivity, and calculate the average conductivity of the two points; Set the data obtained by calculation as the reference conductivity of the sedimentation layer; Parameter 6: Reference conductivity of the mud layer; Take the point with the largest position in the database and the point with the largest conductivity, and calculate the average conductivity of the two points; Set the data obtained by calculation as the reference conductivity of the sedimentation layer;

[0027] Step two: Calculate the position of the mud layer, refer to the attached Figure 4 ; After the reference conductivity is calculated, start the layering by conductivity calculation; preset the equipment installation height, if the case of "reference conductivity of the sedimentation layer" > ("reference conductivity of the clear liquid layer" - 2) occurs, it can be determined that there is no mud layer and no sedimentation layer in the settling tank; At this time, the measurement result is: Clear liquid height = "equipment installation height" - "liquid level position" Sedimentation layer height = 0 Mud layer height = 0; If "reference conductivity of the sedimentation layer" ≤ ("reference conductivity of the clear liquid layer" - 2), it can be determined that there is a sedimentation layer in the settling tank; At this time, take the largest position data in all data groups where "conductivity" ≥ "reference conductivity of the clear liquid layer" - 2, and after this data, there are three consecutive conductivity decreasing trend points, then determine the position of the first point of the consecutive points as the layering point of the clear liquid layer and the sedimentation layer; If ("installation height" - sedimentation layer layering point) < 10 cm, it is determined that there is no mud layer, and the measurement result at this time is: Clear liquid height = "liquid level position" - "sedimentation layer layering point" Sedimentation layer height = "equipment installation height" - "sedimentation layer layering point" Mud layer height = 0; If ("installation height" - sedimentation layer layering point) > 10 cm, and "reference conductivity of the mud layer" ≥ ("reference conductivity of the sedimentation layer" - 2), it is also determined that there is no mud layer; At this time, the measurement result is: Clear liquid height = "liquid level position" - "sedimentation layer layering point" Sedimentation layer height = "equipment installation height" - "sedimentation layer layering point" Mud layer height = 0; If ("installation height" - "settling layer stratification point") > 10 cm, and "mud layer reference conductivity" < ("settling layer reference conductivity" - 2), take the point with the smallest position in the data set greater than "settling layer stratification point", conductivity ≤ ("settling layer reference conductivity" - 2) as A n After this point, there are 3 consecutive non-decreasing points, take the first point of the 3 points as the demarcation point between the settling layer and the mud layer; At this time, the measurement results are: Clear liquid height = "liquid level position" - "settling layer stratification point" Settling layer height = "settling layer stratification point" - "mud layer stratification point" Mud layer height = "equipment installation height" - "mud layer stratification point" If A n After this point, there are 3 consecutive non-decreasing points, take the first point of the 3 points as the demarcation point between the settling layer and the mud layer; At this time, the measurement results are: Clear liquid height = "liquid level position" - "settling layer stratification point" Settling layer height = "equipment installation height" - "settling layer stratification point" Mud layer height = 0.

[0028] Step three: pressure auxiliary judgment; After the conductivity calculation of the mud layer is completed, auxiliary pressure calculation of the mud layer is used, refer to the attached Figure 5 ; Synchronously measure the buoyancy of the material at different positions during the measurement process, which is used to assist in verifying the accuracy of the measurement data; After the probe enters the liquid from the air, because the liquid has buoyancy, a pressure sensor is installed at the support of the conductivity pulley to detect the difference in buoyancy through the change in pressure; During the measurement process, as the probe continues to descend, the pressure value C should continue to increase, and if the stratification is passed, the pressure value C will decrease; The auxiliary measurement logic is as follows: When the buoyancy increases for the first time, it is judged to enter the clear liquid; The second time the buoyancy increases, and continues to increase, it is judged to enter the settling layer; After the second time the buoyancy changes stably, it is judged to enter the mud layer; Record the position point of the first time the buoyancy changes and the liquid level position, if the error does not exceed 20 cm, take the position point calculated by the conductivity as the liquid level position; If the error exceeds 20 cm, take the position point of the buoyancy change as the liquid level position; Record the point where the second time the buoyancy increases, and compare it with the settling layer stratification point, if the error does not exceed 20 cm, take the position point calculated by the conductivity as the settling layer stratification point; If the error exceeds 20 cm, take the position point of the buoyancy change as the settling layer stratification point; After recording the stable point position of the second time of buoyancy change, the error is compared with the mud layer layering point, if the error is not more than 20 cm, the position point calculated by the conductivity is taken as the mud layer layering point; if the error is more than 20 cm, the position point of the buoyancy change is taken as the mud layer layering point; After the pressure auxiliary data is completed, the new data is used for calculation.

[0029] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments are chosen and described in order to explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. An online mudline interface measurement algorithm, characterized in that, The method comprises the following steps: S1, calculating the layered reference conductivity, including: supernatant layer reference conductivity, sediment layer reference conductivity and mud layer reference conductivity; S2, judging whether the difference between the supernatant layer reference conductivity and the sediment layer reference conductivity is greater than 2, so as to judge whether there is a mud layer and a sediment layer in the settling tank, and calculating the mud layer position; S3, after the conductivity calculates the mud layer, the pressure is used to calculate the mud layer: the auxiliary measurement logic is as follows: When the buoyancy increases for the first time, it is judged to enter the supernatant; The second time the buoyancy increases and continues to increase, it is judged to enter the sediment layer; After the second time the buoyancy changes stably, it is judged to enter the mud layer.

2. The online mudline interface measurement algorithm of claim 1, wherein, Before calculating the layered reference conductivity, the conductivity measurement probe and the pressure sensor are controlled to dive by a PLC controlled stepper motor or a private service motor, and the measured position data and the conductivity and pressure data corresponding to the position are stored in a database.

3. The online mudline interface measurement algorithm of claim 2, wherein, In S1, the layered reference conductivity is calculated, specifically including: Taking the point with the minimum position data in the database and the conductivity greater than the conductivity in the air, the position of the data point is calculated to determine the liquid level position; Taking all data points between the point with the maximum position and the point with the maximum conductivity, the average value of the conductivities of all data points is calculated; the calculated data is set as the supernatant layer reference conductivity; Taking the point with the maximum position and the point with the maximum conductivity, the average value of the conductivities of the two position points is calculated; the calculated data is set as the sediment layer reference conductivity; Taking all data points between the point with the maximum position and the point with the maximum conductivity, the average value of the conductivities of all data points is calculated; the calculated data is set as the mud layer reference conductivity.

4. The online mudline interface measurement algorithm of claim 3, wherein, In S2, the mud layer position is calculated, specifically as follows: If "sediment layer reference conductivity" > ("supernatant layer reference conductivity" - 2), then: Supernatant height = "equipment installation height" - "liquid level position" Sediment layer height = 0 Mud layer height = 0 If "sediment layer reference conductivity" ≤ ("supernatant layer reference conductivity" - 2), take the maximum position data in all data groups with "conductivity" ≥ "supernatant layer reference conductivity" - 2, and after this data, there are three continuous conductivity decreasing trend points, then the position of the first point of the continuous points is judged as the layered point of the supernatant layer and the sediment layer; if ("installation height" - sediment layer layered point) < 10 cm at this time, it is judged that there is no mud layer, and the measurement result is: Supernatant height = "liquid level position" - "sediment layer layered point" Sediment layer height = "equipment installation height" - "sediment layer layered point" Mud layer height = 0 If ("installation height" - sediment layer layered point) > 10 cm and "mud layer reference conductivity" ≥ ("sediment layer reference conductivity" - 2), then: Supernatant height = "liquid level position" - "sediment layer layered point" Sediment layer height = "equipment installation height" - "sediment layer layered point" Mud layer height = 0 If ("installation height" - "settlement layer stratification point") > 10 cm, and "mud layer reference conductivity" < ("settlement layer reference conductivity" - 2), take the point with the smallest position in the data set greater than "settlement layer stratification point", conductivity ≤ ("settlement layer reference conductivity" - 2) as A n After this point, there are 3 consecutive non-decreasing trend points, take the first point of the 3 points as the demarcation point between the settlement layer and the mud layer, then: Supernatant height = "liquid level position" - "sediment layer layered point" Sediment layer height = "sediment layer layered point" - "mud layer layered point" Mud layer height = "equipment installation height" - "mud layer layered point"; If there are not 3 non-falling trend points in a row after A n then: Clear liquid height = "liquid level" - "settling layer demixing point" Settling layer height = "equipment installation height" - "settling layer demixing point" Mud layer height = 0.

5. The online mudline interface measurement algorithm of claim 4, wherein, S3 auxiliary pressure calculation mud layer, as follows: Record the first buoyancy change point compared with the liquid level, the error is not more than 20 cm, take the conductivity calculated position point as the liquid level; if the error exceeds 20 cm, take the buoyancy change point as the liquid level; Record the second buoyancy change point compared with the settling layer demixing point, the error is not more than 20 cm, take the conductivity calculated position point as the settling layer demixing point; if the error exceeds 20 cm, take the buoyancy change point as the settling layer demixing point; Record the second buoyancy change point compared with the settling layer demixing point, the error is not more than 20 cm, take the conductivity calculated position point as the settling layer demixing point; if the error exceeds 20 cm, take the buoyancy change point as the settling layer demixing point.

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