Control methods for large flotation machines

Abstract

This invention discloses a control method for a large-scale flotation machine, comprising: a programmable logic controller (PLC) electrically connected to a rangefinder, a slurry level detector, and a slurry discharge gate, respectively, to acquire real-time foam height data and slurry level data, and to control the foam output based on the foam height data and slurry level data. By directly using the foam height data of the foam tank for judgment and regulation, influencing factors are reduced, thereby ensuring uniform foam output after regulation and making the flotation machine's operation more stable.

Description

Technical Field

[0001] This invention relates to the field of flotation machine control technology, and more specifically, to a control method for a large flotation machine. Background Technology

[0002] Flotation machines are an important piece of equipment in mining machinery. Their main function is to aerate the air, causing minerals with common characteristics to adhere to the bubbles, float, and overflow through the overflow weir, while other minerals sink. The most crucial step is foam removal. Flotation machines need to maintain a stable foam removal rate to ensure the stability of the next process. This is achieved through scrapers or by allowing the foam to flow by gravity into the foam tank. Currently, the simplest control method is to regulate the foam removal rate by controlling the liquid level. However, due to variations in mineral properties and conditions, the abundance of foam is not constant; sometimes there is little foam, and sometimes there is a lot, which negatively impacts the stable control of the flotation machine.

[0003] The prior art (application number: 201911341940.6, application date: 2019.12.24) discloses an intelligent monitoring device and method for the slurry and foam fullness of a flotation cell, including: Step 3, based on the establishment of a standard model, setting a reasonable corresponding foam height safety threshold Hmax according to the actual situation of the concentrator, the safety threshold Hmax can be customized in the BIM server as needed; Step 4, installing LDGMIK electromagnetic flowmeters on the slurry input and output pipes of the flotation cell using pipe flanges to monitor the slurry volume change Vx in the cell. The computer calculates the flow rate according to the formula... The changes in the slurry level within the flotation cell are calculated. A DS-2CD3T86FWDV2-I5S high-definition camera is installed diagonally above the flotation cell to obtain real-time images of the foam on the surface. The camera's field of view provides full coverage of the flotation cell surface. Water-powered ZDLP-40 electronic single-seat regulating valves (containing a 381L electronic actuator) are installed on the slurry input and output pipes of the flotation cell using pipe flanges to adjust the actual diameter of the slurry input and output pipes, thereby regulating the slurry output rate. The electric regulating valves are equipped with 381L electronic actuators for automatic control. The actuator program transmits information to the BIM server via an open OPC interface through a network switch. When the foam layer height in the flotation cell is normal, the valve opening is h1 = 0.11m. When the foam layer height in the flotation cell reaches the safety threshold, the valve opening automatically adjusts to h2 = 0.17m. In other words, existing technologies disclose adjusting the pulp output rate by controlling the thickness of the froth layer within the flotation cell, and adjusting the pulp output rate affects the froth output. Since there is a relatively long process from the froth in the flotation cell to its discharge from the froth tank, and many factors affect the froth discharge during this process, even if existing technologies can indirectly affect the froth output from the froth tank by controlling the thickness of the froth layer within the flotation cell, this control of the froth output still has a significant margin of error.

[0004] Therefore, how to directly use the amount of foam output as a regulatory factor to reduce the impact of errors is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention provides a control method for a large-scale flotation machine, comprising:

[0006] The rangefinder detects foam height data, including: the rangefinder is installed on the side of the foam tank of the flotation machine away from the ground, the measuring end of the rangefinder is parallel to the ground, and along a direction perpendicular to the ground, the orthographic projection of the measuring end of the rangefinder onto the ground is within the orthographic projection range of the foam tank onto the ground; the rangefinder detects the height information of the position corresponding to the position of the foam liquid surface in the foam tank and the measuring end of the rangefinder along a direction perpendicular to the ground, and uses the height information as the foam height data;

[0007] The slurry level detector detects slurry level height data, including: the slurry level detector extends in a direction perpendicular to the ground and is fixed in the flotation cell of the flotation machine; the slurry level in the flotation cell contacts the float of the slurry level detector, and the slurry level detector detects the slurry level height data according to the position of the float;

[0008] The programmable logic controller (PLC) is electrically connected to a rangefinder, a slurry level detector, and a slurry discharge gate, respectively, to acquire the foam height data and the slurry level data in real time. Based on the foam height data and the slurry level data, the PLC controls the foam discharge rate, including:

[0009] At time t, the programmable logic controller acquires the foam height data and the slurry level height data at time t;

[0010] Determine whether the foam height data at time t is greater than the foam height limit;

[0011] If the foam height data at time t is greater than the foam height limit, obtain all the foam height data from time t to time t+k, and determine whether all the foam height data from time t to time t+k are greater than the foam height limit.

[0012] If all the foam height data from time t to time t+k are greater than the foam height limit, the slurry level height data at time t is taken as the current level value, and the opening of the slurry discharge gate is increased until the latest acquired slurry level height data is equal to the current level value minus the preset change value, and then the opening of the slurry discharge gate remains unchanged.

[0013] If the foam height data at time t is less than or equal to the foam height limit, or if at least one foam height data is less than or equal to the foam height limit between time t and time t+k, determine whether the slurry surface height data at time t is less than the surface low limit.

[0014] If the slurry level height data at time t is less than the minimum level value, obtain all the slurry level height data from time t to time t+k, and determine whether all the slurry level height data from time t to time t+k are less than the minimum level value.

[0015] If all the slurry level height data from time t to time t+k are less than the minimum level value, the slurry level height data at time t is taken as the current level value, and the opening of the slurry discharge gate is reduced until the latest acquired slurry level height data is equal to the current level value plus a preset change value, and then the opening of the slurry discharge gate remains unchanged.

[0016] If the slurry level height data at time t is greater than or equal to the lower limit of the slurry level, or if at least one slurry level height data is greater than or equal to the lower limit of the slurry level between time t and time t+k, the judgment ends.

[0017] Optionally, if the slurry level height data at time t is greater than or equal to the lower limit of the liquid level, the method further includes: within a preset time range from the time when it is determined that the slurry level height data at time t is greater than or equal to the lower limit of the liquid level, the programmable logic controller does not acquire the foam height data and the slurry level height data.

[0018] Optionally, if at least one of the slurry level height data is greater than or equal to the lower limit value between time t and time t+k, the method further includes: within a preset time range from the time when it is determined that at least one of the slurry level height data is greater than or equal to the lower limit value between time t and time t+k, the programmable logic controller does not acquire the foam height data and the slurry level height data.

[0019] Optionally, the orthographic projection of the measuring end of the rangefinder onto the ground along a direction perpendicular to the ground lies within the orthographic projection range of the foam tank onto the ground, including:

[0020] The foam tank includes a circular groove and an opening communicating with the circular groove. The orthographic projection of the measuring end of the rangefinder onto the ground is located within the orthographic projection range of the opening onto the ground along a direction perpendicular to the ground.

[0021] Optionally, the orthographic projection of the measuring end of the rangefinder onto the ground along a direction perpendicular to the ground lies within the orthographic projection range of the foam tank onto the ground, including:

[0022] The foam tank includes a circular groove and two openings communicating with the circular groove. The diameter of the circular groove is taken, and the two openings are symmetrically arranged along the diameter. In a direction perpendicular to the ground, the orthographic projection of the measuring end of the rangefinder on the ground is located within the orthographic projection range of the circular groove on the ground, and the orthographic projection of the measuring end of the rangefinder on the ground at least partially overlaps with the orthographic projection of the diameter on the ground. Taking the orthographic projection of the center of the circular groove on the ground as the vertex, the angle formed by the orthographic projection of the connection point between any of the openings and the circular groove on the ground and the orthographic projection of the measuring end of the rangefinder on the ground is an acute angle.

[0023] Compared with the prior art, the control method for large-scale flotation machines provided by the present invention achieves at least the following beneficial effects:

[0024] 1. The control method for a large-scale flotation machine provided by this invention includes: a programmable logic controller (PLC) electrically connected to a rangefinder, a slurry level detector, and a slurry discharge gate, respectively, to acquire real-time foam height data and slurry level data, and to control the foam output based on the foam height data and slurry level data. By directly using the foam height data of the foam tank for judgment and regulation, influencing factors are reduced, thereby ensuring uniform foam output after regulation and making the flotation machine's operation more stable.

[0025] 2. The control method for a large-scale flotation machine provided by this invention includes: determining whether the foam height data at time t is greater than a foam height limit; if the foam height data at time t is greater than the foam height limit, acquiring all foam height data from time t to time t+k, and determining whether all foam height data from time t to time t+k are greater than the foam height limit; if the foam height data at time t is less than or equal to the foam height limit, or if at least one foam height data from time t to time t+k is less than or equal to the foam height limit, determining whether the slurry level height data at time t is less than a slurry level limit; if the slurry level height data at time t is less than the slurry level limit, acquiring all slurry level height data from time t to time t+k, and determining whether all slurry level height data from time t to time t+k are less than the slurry level limit. Through multi-level judgment and control of foam height data and slurry level height data, the control of foam output is made more precise.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the technical effects described above at the same time.

[0027] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0029] Figure 1 This is a schematic flowchart of a control method for a large flotation machine provided by the present invention.

[0030] Figure 2 This is another schematic diagram of the control method for a large flotation machine provided by the present invention.

[0031] Figure 3 This is another schematic diagram of the control method for a large flotation machine provided by the present invention.

[0032] Figure 4 This is a schematic diagram of a foam tank structure.

[0033] Figure 5 yes Figure 4 A cross-sectional view of line A-A'.

[0034] In the diagram: 1. Foam tank; 2. Circular tank; 3. Tank opening; 4. Foam liquid surface; 5. Rangefinder; Z, direction perpendicular to the ground. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0038] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0040] Example 1

[0041] Reference Figure 1 , Figure 1 This is a flowchart illustrating a control method for a large-scale flotation machine provided by the present invention, used to illustrate a specific embodiment of the control method for a large-scale flotation machine provided by the present invention, including:

[0042] S101: The rangefinder detects foam height data, including: the rangefinder is installed on the side of the foam tank of the flotation machine away from the ground, the measuring end of the rangefinder is parallel to the ground, and the orthographic projection of the measuring end of the rangefinder on the ground is within the orthographic projection range of the foam tank on the ground along the direction perpendicular to the ground; the rangefinder detects the height information of the position corresponding to the measuring end of the rangefinder in the foam tank along the direction perpendicular to the ground, and uses the height information as foam height data;

[0043] S102: The slurry level detector detects the slurry level height data, including: the slurry level detector extends in a direction perpendicular to the ground and is fixed in the flotation cell of the flotation machine; the slurry level in the flotation cell contacts the float of the slurry level detector, and the slurry level detector detects the slurry level height data according to the position of the float;

[0044] S103: The programmable logic controller (PLC) is electrically connected to the rangefinder, slurry level detector, and slurry discharge gate to acquire real-time foam height and slurry level data. Based on these data, it controls the foam discharge rate, including:

[0045] S1031: At time t, the programmable logic controller acquires the foam height data and the slurry level height data at time t;

[0046] S1032: Determine whether the foam height data at time t is greater than the foam height limit;

[0047] S10321: If the foam height data at time t is greater than the foam height limit, obtain all foam height data from time t to time t+k, and determine whether all foam height data from time t to time t+k are greater than the foam height limit.

[0048] S103211: If all foam height data from time t to time t+k are greater than the foam height limit, the slurry level height data at time t is used as the current level value, and the slurry discharge gate is opened more frequently until the latest slurry level height data is equal to the current level value minus the preset change value, and then the opening of the slurry discharge gate remains unchanged.

[0049] S10322: If the foam height data at time t is less than or equal to the foam height limit, determine whether the slurry surface height data at time t is less than the surface lower limit.

[0050] S103212: If there is at least one foam height data less than or equal to the foam height limit between time t and time t+k, determine whether the slurry liquid level height data at time t is less than the liquid level limit.

[0051] S10331: If the slurry level height data at time t is less than the lower limit of the slurry level, obtain all slurry level height data from time t to time t+k, and determine whether all slurry level height data from time t to time t+k are less than the lower limit of the slurry level.

[0052] S103311: If all slurry level height data from time t to time t+k are less than the lower limit of the slurry level, the slurry level height data at time t is used as the current slurry level value, and the opening of the slurry discharge gate is reduced until the latest slurry level height data is equal to the current slurry level value plus the preset change value, and then the opening of the slurry discharge gate remains unchanged.

[0053] S10332: If the slurry level height at time t is greater than or equal to the lower limit of the slurry level, the judgment ends;

[0054] S103312: If at least one slurry level height data is greater than or equal to the lower limit value between time t and time t+k, the judgment ends.

[0055] It should be noted that the rangefinder can be a conventional laser rangefinder. This embodiment does not modify the specific structure of the rangefinder. The laser rangefinder uses its laser to measure the foam surface in the foam tank. The laser rangefinder can directly obtain the distance from its measuring end to the foam surface in the foam tank. Combined with the rangefinder's own calibration height, it outputs the height information of the foam surface in the foam tank corresponding to the measuring end of the laser rangefinder, i.e., the foam height data. Similarly, the slurry level detector can also use existing technology, such as the "Novel Slurry Level Detection Device" disclosed in application number 202020693915.6, but it is not limited to this. The Programmable Logic Controller (PLC) executes the control judgment. Specifically, the PLC uses PID logic control when controlling the opening of the slurry discharge gate. Monitoring the actual liquid level in the flotation cell and controlling the valve opening in real time based on optimized PID logic control parameters is a relatively mature technology in this field. There are also various methods for PID logic control calculations, such as the control method mentioned in the "High-Precision Automatic Liquid Level Control System" disclosed in application number 202511193880.3. Of course, it is not limited to this method, and adjustments and selections can be made according to actual needs. This application does not impose specific restrictions on this.

[0056] Understandably, the programmable logic controller (PLC) is electrically connected to the rangefinder, slurry level detector, and slurry discharge gate to acquire real-time data on foam height and slurry level. Based on this data, the foam output is controlled. The foam profile flow rate in the foam tank is linearly related to the foam height data, representing the total flow rate of the foam tank. By directly using the foam height data for judgment and control, influencing factors are reduced, ensuring uniform foam output after control and making the flotation machine's operation more stable. The system determines whether the foam height data at time t is greater than the foam height limit. If the foam height data at time t is greater than the foam height limit, it retrieves all foam height data from time t to time t+k and determines whether all foam height data from time t to time t+k are greater than the foam height limit. If the foam height data at time t is less than or equal to the foam height limit, or if at least one foam height data from time t to time t+k is less than or equal to the foam height limit, it determines whether the slurry level height data at time t is less than the slurry level limit. If the slurry level height data at time t is less than the slurry level limit, it retrieves all slurry level height data from time t to time t+k and determines whether all slurry level height data from time t to time t+k are less than the slurry level limit. Through multi-level judgment and control of foam height data and slurry level height data, the control of foam output becomes more precise.

[0057] Example 2

[0058] Reference Figure 2 , Figure 3 , Figure 4 and Figure 5 , Figure 2 This is another schematic flowchart of the control method for a large flotation machine provided by the present invention. Figure 3 This is another schematic diagram of the control method for a large flotation machine provided by the present invention. Figure 4 This is a schematic diagram of a foam tank structure. Figure 5 yes Figure 4 A cross-sectional view along line A-A' is provided to illustrate another specific embodiment of the control method for a large-scale flotation machine provided by the present invention, including:

[0059] S201: A rangefinder detects foam height data, including: the rangefinder is installed on the side of the foam tank of the flotation machine away from the ground, with the measuring end of the rangefinder parallel to the ground; the foam tank includes a circular tank and an opening communicating with the circular tank, and along the direction perpendicular to the ground, the orthographic projection of the measuring end of the rangefinder onto the ground is located within the orthographic projection range of the opening onto the ground; or, the foam tank includes a circular tank and two openings communicating with the circular tank, taking the diameter of the circular tank, with the two openings symmetrically arranged along the diameter; along the direction perpendicular to the ground, the rangefinder's measurement... The orthographic projection of the measuring end on the ground is located within the orthographic projection range of the circular groove on the ground, and the orthographic projection of the measuring end of the rangefinder on the ground at least partially overlaps with the orthographic projection of the diameter on the ground; taking the orthographic projection of the center of the circular groove on the ground as the vertex, the angle formed by the orthographic projection of any groove opening and the connection point of the circular groove on the ground and the orthographic projection of the measuring end of the rangefinder on the ground is an acute angle; the rangefinder detects the height information of the position corresponding to the measuring end of the rangefinder in the foam tank along the direction perpendicular to the ground, and uses the height information as foam height data.

[0060] S202: The slurry level detector detects the slurry level height data, including: the slurry level detector extends in a direction perpendicular to the ground and is fixed in the flotation cell of the flotation machine; the slurry level in the flotation cell contacts the float of the slurry level detector, and the slurry level detector detects the slurry level height data according to the position of the float;

[0061] S203: The programmable logic controller (PLC) is electrically connected to the rangefinder, slurry level detector, and slurry discharge gate to acquire real-time foam height and slurry level data. Based on these data, it controls the foam discharge rate, including:

[0062] S2031: At time t, the programmable logic controller acquires the foam height data and the slurry level height data at time t;

[0063] S2032: Determine whether the foam height data at time t is greater than the foam height limit;

[0064] S20321: If the foam height data at time t is greater than the foam height limit, obtain all foam height data from time t to time t+k, and determine whether all foam height data from time t to time t+k are greater than the foam height limit.

[0065] S203211: If all foam height data from time t to time t+k are greater than the foam height limit, the slurry level height data at time t is used as the current level value, and the slurry discharge gate is opened more frequently until the latest slurry level height data is equal to the current level value minus the preset change value, and then the opening of the slurry discharge gate remains unchanged.

[0066] S20322: If the foam height data at time t is less than or equal to the foam height limit, determine whether the slurry surface height data at time t is less than the surface lower limit.

[0067] S203212: If there is at least one foam height data less than or equal to the foam height limit between time t and time t+k, determine whether the slurry liquid level height data at time t is less than the liquid level limit.

[0068] S20331: If the slurry level height data at time t is less than the lower limit of the slurry level, obtain all slurry level height data from time t to time t+k, and determine whether all slurry level height data from time t to time t+k are less than the lower limit of the slurry level.

[0069] S203311: If all slurry level height data from time t to time t+k are less than the lower limit of the slurry level, the slurry level height data at time t is used as the current slurry level value, and the opening of the slurry discharge gate is reduced until the latest slurry level height data is equal to the current slurry level value plus the preset change value, and then the opening of the slurry discharge gate remains unchanged.

[0070] S20332: If the slurry level height data at time t is greater than or equal to the lower limit of the slurry level, the judgment ends, and within a preset time range from the time when the slurry level height data at time t is determined to be greater than or equal to the lower limit of the slurry level, the programmable logic controller does not acquire foam height data and slurry level height data.

[0071] S203312: If at least one slurry level height data is greater than or equal to the lower limit of the slurry level between time t and time t+k, the judgment ends, and within a preset time range from the time when it is determined that at least one slurry level height data is greater than or equal to the lower limit of the slurry level between time t and time t+k, the programmable logic controller does not acquire foam height data and slurry level height data.

[0072] It should be noted that, referring to Figure 4 and Figure 5The foam tank 1 includes a circular tank and an opening 3 connected to the circular tank. Foam is discharged only from the opening 3. The measuring end of the rangefinder 5 measures the height of the foam liquid level 4 at the opening 3 to most accurately represent the foam output. Therefore, the measuring end of the rangefinder 5 is set parallel to the ground, along the direction Z perpendicular to the ground, and the orthographic projection of the measuring end of the rangefinder 5 on the ground is within the orthographic projection range of the opening 3 on the ground. When the foam tank includes a circular tank and two openings connected to the circular tank, the foam flows to the two openings and is discharged from the two openings. The two openings are close together, and the two flowing liquid pairs will cause large fluctuations in the foam liquid level height at the opening, resulting in a large difference from the actual foam output at the opening. Therefore, the measuring end of the rangefinder is set to measure the foam liquid level height near the opening of the circular tank to improve the accuracy of the foam liquid level height measurement. In this embodiment, the value of k ranges from 10 seconds to 30 seconds, referring to... Figure 3 Taking a value of 30 seconds as an example, the value of k can be selected according to actual needs, such as k=10 seconds, k=15 seconds, k=20 seconds, k=25 seconds, k=30 seconds, or any value between 10 and 30 seconds. After determining that the foam height data is greater than the foam height limit and the slurry level height data is less than the slurry level limit, the duration needs to be determined. The duration is to reduce the sensitivity to slurry level fluctuations. The longer the duration, i.e., the length of k, the lower the sensitivity and the lower the probability of false triggering. However, the duration cannot be too long, as this may cause the flotation cell to fill up. Therefore, k is set to be less than or equal to 30 seconds. If the duration is too short, the reaction will be too frequent, and the flotation machine will constantly adjust the slurry level, resulting in slurry level oscillations. Therefore, the value of k should be greater than or equal to 10 seconds. Of course, the value of k can be adjusted for different flotation machines and is not limited to 10 to 30 seconds. (Refer to...) Figure 3In steps S203211 and S203311, the preset change value can be 10, but it is not limited to this and can be selected according to specific circumstances. This embodiment does not impose specific restrictions on this. In step S20322, when it is determined that the foam height data at time t is less than or equal to the foam height limit, the process immediately proceeds to determine whether the slurry surface height data at time t is less than the slurry surface lower limit. In step S203212, when it is determined that there is at least one foam height data less than or equal to the foam height limit between time t and time t+k, the process immediately proceeds to determine whether the slurry surface height data at time t is less than the slurry surface lower limit. In steps S20332 and S203312, the programmable logic controller (PLC) does not acquire foam height data and slurry level height data within a preset time range starting from the moment it is determined that the slurry level height data at time t is greater than or equal to the lower limit of the slurry level. Similarly, the PLC does not acquire foam height data and slurry level height data within a preset time range starting from the moment it is determined that at least one slurry level height data is greater than or equal to the lower limit of the slurry level between time t and time t+k. This is because the flotation machine is large, and level control requires reaction time. Without a preset waiting time range, the flotation machine would continuously fluctuate between the settling tank and the full tank. For details, refer to... Figure 3 The preset time range can be 2 minutes, or it can be 2.5 minutes, 3 minutes, etc., and can be set according to actual needs. This embodiment does not impose specific restrictions on this.

[0073] Understandably, the control method for large flotation machines provided by this invention involves installing a laser rangefinder in the flotation machine's froth collection tank (i.e., the froth tank). The froth thickness in the froth tank is used to determine the froth discharge rate, thereby controlling the froth discharge gate. When the froth is thicker, it indicates a larger froth discharge rate; in this case, the gate opening is increased to lower the froth level and reduce the froth discharge. Conversely, when there is less froth, the gate opening is decreased to raise the level and increase the froth discharge. This effectively solves the problem of uneven froth discharge caused by froth variations. It directly controls the flotation machine based on its fundamental needs, rather than indirectly controlling the froth discharge rate by controlling the froth level in the flotation tank. This avoids all influencing factors and directly controls the root cause based on the result. Uniform froth discharge has less impact on the system, making it more stable. Through multi-level judgment and control based on froth height data and slurry level data, the control of froth discharge rate becomes more precise.

[0074] As can be seen from the above embodiments, the control method for large-scale flotation machines provided by the present invention achieves at least the following beneficial effects:

[0075] 1. The control method for a large-scale flotation machine provided by this invention includes: a programmable logic controller (PLC) electrically connected to a rangefinder, a slurry level detector, and a slurry discharge gate, respectively, to acquire real-time foam height data and slurry level data, and to control the foam output based on the foam height data and slurry level data. By directly using the foam height data of the foam tank for judgment and regulation, influencing factors are reduced, thereby ensuring uniform foam output after regulation and making the flotation machine's operation more stable.

[0076] 2. The control method for a large-scale flotation machine provided by this invention includes: determining whether the foam height data at time t is greater than a foam height limit; if the foam height data at time t is greater than the foam height limit, acquiring all foam height data from time t to time t+k, and determining whether all foam height data from time t to time t+k are greater than the foam height limit; if the foam height data at time t is less than or equal to the foam height limit, or if at least one foam height data from time t to time t+k is less than or equal to the foam height limit, determining whether the slurry level height data at time t is less than a slurry level limit; if the slurry level height data at time t is less than the slurry level limit, acquiring all slurry level height data from time t to time t+k, and determining whether all slurry level height data from time t to time t+k are less than the slurry level limit. Through multi-level judgment and control of foam height data and slurry level height data, the control of foam output is made more precise.

[0077] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A control method for a large-scale flotation machine, characterized in that, include: The rangefinder detects foam height data, including: the rangefinder is installed on the side of the foam tank of the flotation machine away from the ground, the measuring end of the rangefinder is parallel to the ground, and along a direction perpendicular to the ground, the orthographic projection of the measuring end of the rangefinder onto the ground is within the orthographic projection range of the foam tank onto the ground; the rangefinder detects the height information of the position corresponding to the position of the foam liquid surface in the foam tank and the measuring end of the rangefinder along a direction perpendicular to the ground, and uses the height information as the foam height data; The slurry level detector detects slurry level height data, including: the slurry level detector extends in a direction perpendicular to the ground and is fixed in the flotation cell of the flotation machine; the slurry level in the flotation cell contacts the float of the slurry level detector, and the slurry level detector detects the slurry level height data according to the position of the float; The programmable logic controller (PLC) is electrically connected to a rangefinder, a slurry level detector, and a slurry discharge gate, respectively, to acquire the foam height data and the slurry level data in real time. Based on the foam height data and the slurry level data, the PLC controls the foam discharge rate, including: At time t, the programmable logic controller acquires the foam height data and the slurry level height data at time t; Determine whether the foam height data at time t is greater than the foam height limit; If the foam height data at time t is greater than the foam height limit, obtain all the foam height data from time t to time t+k, and determine whether all the foam height data from time t to time t+k are greater than the foam height limit. If all the foam height data from time t to time t+k are greater than the foam height limit, the slurry level height data at time t is taken as the current level value, and the opening of the slurry discharge gate is increased until the latest acquired slurry level height data is equal to the current level value minus the preset change value, and then the opening of the slurry discharge gate remains unchanged. If the foam height data at time t is less than or equal to the foam height limit, or if at least one foam height data is less than or equal to the foam height limit between time t and time t+k, determine whether the slurry surface height data at time t is less than the surface low limit. If the slurry level height data at time t is less than the minimum level value, obtain all the slurry level height data from time t to time t+k, and determine whether all the slurry level height data from time t to time t+k are less than the minimum level value. If all the slurry level height data from time t to time t+k are less than the minimum level value, the slurry level height data at time t is taken as the current level value, and the opening of the slurry discharge gate is reduced until the latest acquired slurry level height data is equal to the current level value plus a preset change value, and then the opening of the slurry discharge gate remains unchanged. If the slurry level height data at time t is greater than or equal to the lower limit of the slurry level, or if at least one slurry level height data is greater than or equal to the lower limit of the slurry level between time t and time t+k, the judgment ends.

2. The control method for a large-scale flotation machine according to claim 1, characterized in that, If the slurry level height data at time t is greater than or equal to the lower limit of the liquid level, the method further includes: within a preset time range from the time when it is determined that the slurry level height data at time t is greater than or equal to the lower limit of the liquid level, the programmable logic controller does not acquire the foam height data and the slurry level height data.

3. The control method for a large-scale flotation machine according to claim 1, characterized in that, If at least one of the slurry level height data is greater than or equal to the lower limit value between time t and time t+k, the method further includes: within a preset time range starting from the time when it is determined that at least one of the slurry level height data is greater than or equal to the lower limit value between time t and time t+k, the programmable logic controller does not acquire the foam height data and the slurry level height data.

4. The control method for a large-scale flotation machine according to claim 1, characterized in that, The condition that the orthographic projection of the measuring end of the rangefinder onto the ground lies within the orthographic projection range of the foam tank onto the ground along a direction perpendicular to the ground includes: The foam tank includes a circular groove and an opening communicating with the circular groove. The orthographic projection of the measuring end of the rangefinder onto the ground is located within the orthographic projection range of the opening onto the ground along a direction perpendicular to the ground.

5. The control method for a large-scale flotation machine according to claim 1, characterized in that, The condition that the orthographic projection of the measuring end of the rangefinder onto the ground lies within the orthographic projection range of the foam tank onto the ground along a direction perpendicular to the ground includes: The foam tank includes a circular groove and two openings communicating with the circular groove. The diameter of the circular groove is taken, and the two openings are symmetrically arranged along the diameter. In a direction perpendicular to the ground, the orthographic projection of the measuring end of the rangefinder on the ground is located within the orthographic projection range of the circular groove on the ground, and the orthographic projection of the measuring end of the rangefinder on the ground at least partially overlaps with the orthographic projection of the diameter on the ground. Taking the orthographic projection of the center of the circular groove on the ground as the vertex, the angle formed by the orthographic projection of the connection point between any of the openings and the circular groove on the ground and the orthographic projection of the measuring end of the rangefinder on the ground is an acute angle.

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