Automatic cleaning control method of horizontal centrifuge and centrifuge

Abstract

The present application relates to the technical field of centrifuge cleaning, in particular to an automatic cleaning control method of a horizontal centrifuge and the centrifuge. The method periodically cleans the horizontal centrifuge, collects turbidity data of heavy phase end and light phase end discharge of each cycle; determines a desorption index according to turbidity difference characteristics between the turbidity data of the heavy phase end and the turbidity data of the light phase end of each cycle; determines a change index according to the change trend of the desorption index; if the change index is not less than a preset speed-up threshold, determines a differential speed adjustment coefficient according to the change index and the desorption index; adjusts the upper limit value of the differential speed based on the differential speed adjustment coefficient, and updates the upper limit value of the differential speed of all subsequent cycles to a target upper limit value of the differential speed; if the desorption indexes of continuous M cycles meet the end cleaning condition, executes the end cleaning strategy in the current cycle; if the desorption indexes of continuous T cycles meet the stop cleaning condition, stops cleaning in the current cycle, thereby intelligently cleaning the centrifuge and improving the cleaning efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of centrifuge control, and particularly relates to an automatic cleaning control method of a horizontal centrifuge and the centrifuge. BACKGROUND

[0002] The horizontal centrifuge is widely applied to the solid-liquid separation process in the chemical industry, pharmaceutical industry, food industry, environmental protection industry and the like. In the long-term operation of the centrifuge, the phenomenon of material residues on the inner wall of the drum and the structure of the screw propeller is inevitable, and if the cleaning is not in time, the centrifugal separation effect will be affected, and even the equipment will be damaged. Therefore, cleaning the centrifuge has become an important technical means to ensure the stable operation of the horizontal centrifuge.

[0003] At present, in the prior art, when the cleaning operation is performed on the horizontal centrifuge, the differential speed of the drum speed and the screw propeller is set as a fixed value, and the centrifuge is cleaned by this static control method. However, this method lacks real-time sensing and dynamic response ability to the residue state of the internal pollutants of the equipment, and is prone to problems such as increased energy consumption and accelerated equipment wear due to excessively high speed, or incomplete cleaning and prolonged time due to excessively low speed, and the like. Moreover, since the degree of desorption of the residues on the inner wall of the drum and the screw propeller is different at different periods as the cleaning process continuously advances, the desorption trend of the residues is not considered, and the differential speed is not dynamically adjusted in time during the cleaning process, which makes it difficult to guarantee the cleaning accuracy and efficiency. Especially in the final stage of cleaning, the residues are reduced, and the centrifuge is cleaned by the static control method, which is prone to resource waste. SUMMARY

[0004] In order to solve the technical problem, the present application provides an automatic cleaning control method of a horizontal centrifuge and the centrifuge, and the technical solution is as follows:

[0005] The present application provides an automatic cleaning control method of a horizontal centrifuge, which comprises the following steps:

[0006] Periodically cleaning the horizontal centrifuge, collecting the turbidity data of the heavy phase end and the light phase end of each cycle, wherein the upper limit value of the differential speed of the screw propeller and the drum is preset for each cycle;

[0007] For each cycle, according to the turbidity difference characteristics between the turbidity data of the heavy phase end and the turbidity data of the light phase end, a desorption index for quantifying the desorption degree of the residues is determined;

[0008] According to the change trend of the desorption index in the current period and the previous N consecutive periods, a change index is determined; if the change index is not less than a preset acceleration threshold, a difference rotation speed adjustment coefficient is determined according to the change index and the desorption indexes of the previous N consecutive periods; based on the difference rotation speed adjustment coefficient, the upper limit value of the difference rotation speed is adjusted to obtain a target upper limit value of the difference rotation speed, and the upper limit value of the difference rotation speed of all subsequent periods is updated to the target upper limit value of the difference rotation speed;

[0009] If the desorption indexes of the previous M consecutive periods meet the end cleaning condition, the rotation speed of the screw propeller is kept synchronous with the rotation speed of the drum and the weir height of the light phase overflow port is reduced in the current period;

[0010] If the desorption indexes of the previous T consecutive periods meet the stop cleaning condition, cleaning is stopped in the current period, and the centrifuge is converted to a dewatering mode, wherein N, M and T are positive integers, N≥2, and T is greater than M.

[0011] Further, each period includes three consecutive difference rotation speed control stages, an automatic cleaning control method of a horizontal centrifuge includes:

[0012] In the first stage, the difference rotation speed of the screw propeller and the drum is gradually increased from an initial value to an upper limit value of the difference rotation speed at a preset first rate;

[0013] In the second stage, the difference rotation speed is gradually decreased from the upper limit value of the difference rotation speed to a stable value at a preset second rate, wherein the stable value is less than or equal to the initial value;

[0014] In the third stage, the difference rotation speed is kept at the stable value until the next period.

[0015] Further, an automatic cleaning control method of a horizontal centrifuge includes:

[0016] For each period, turbidity data of heavy phase end drainage in the second and third stages is collected as a first data set, and turbidity data of light phase end drainage in the first stage is collected as a second data set;

[0017] The first data set is arranged in ascending order of turbidity value to generate a first turbidity sequence; a subset greater than the upper quartile in the first turbidity sequence is extracted as first effective turbidity data of the heavy phase end;

[0018] The second data set is arranged in ascending order of turbidity value to generate a second turbidity sequence; a subset less than the lower quartile in the second turbidity sequence is extracted as second effective turbidity data of the light phase end.

[0019] Further, the desorption index determination process includes:

[0020] calculating an average value of all turbidity values in the first effective turbidity data to obtain a first average value;

[0021] calculating an average value of all turbidity values in the second effective turbidity data to obtain a second average value;

[0022] taking a difference value between the first average value and the second average value as a desorption index.

[0023] Further, the change index determination process comprises:

[0024] obtaining historical same-period cleaning records, the historical same-period cleaning records comprising second average values of respective historical periods;

[0025] for a time sequence composed of N consecutive periods to a current period, for each period, extracting a second average value of a historical period at a same sequence position as the i-th period from the historical same-period cleaning records; taking a maximum value of the second average values of the historical periods as a maximum second average value, wherein i=1, 2, …, N+1, i=N+1 corresponds to the current period;

[0026] based on the second average value corresponding to the i-th period and the maximum second average value, obtaining a desorption confidence of the i-th period through a preset confidence calculation function;

[0027] taking the desorption confidence as a weight, performing weighted linear regression on the desorption indexes in the current period and the N consecutive periods to obtain a fitting straight line, and taking a slope of the fitting straight line as a change index.

[0028] Further, taking the desorption confidence as a weight, performing weighted linear regression on the desorption indexes in the current period and the N consecutive periods to obtain a fitting straight line, comprises:

[0029] obtaining a starting time of the i-th period;

[0030] taking the starting time of the i-th period as an independent variable, the desorption index of the i-th period as a dependent variable, and the desorption confidence as a weight, performing weighted linear regression on the desorption indexes in the current period and the N consecutive periods to obtain a regression curve, performing linear fitting on the regression curve through a least square method to obtain a fitting straight line.

[0031] Further, the difference rotation speed adjustment coefficient determination process comprises:

[0032] selecting a minimum desorption index from the desorption indexes of the N consecutive periods;

[0033] calculating a difference value between the desorption index of the current period and the minimum desorption index to obtain a first difference value;

[0034] normalizing a product of the first difference value and the change index to obtain a difference rotation speed adjustment coefficient.

[0035] Further, the end-stage cleaning condition comprises that there are continuous M cycles, and simultaneously, M is not more than a preset first cycle number threshold, and the desorption index of each cycle in the continuous M cycles is less than a preset desorption threshold.

[0036] Further, the stop cleaning condition comprises that there are continuous T cycles, and simultaneously, T is not less than a preset second cycle number threshold, and the desorption index of each cycle in the continuous T cycles is less than a preset desorption threshold, wherein the preset second cycle number threshold is greater than the preset first cycle number threshold.

[0037] A horizontal centrifuge, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of the automatic cleaning control method of the horizontal centrifuge when executing the computer program.

[0038] The present application has the following beneficial effects:

[0039] The periodic cleaning horizontal centrifuge collects turbidity data of heavy phase end and light phase end discharge in each cycle, so as to determine the desorption index according to the turbidity data difference between the heavy phase end and the light phase end discharge, and quantize the desorption degree of the residual in different periods in the cleaning process through the desorption index. Next, the change trend (change index) of the desorption index of continuous multiple cycles is used to intelligently decide whether the differential speed between the drum and the screw propeller needs to be adjusted in the current cycle, and simultaneously, the upper limit value of the differential speed of all subsequent cycles is updated in advance, so as to optimize the future cleaning efficiency. Then, the end-stage cleaning condition and the stop cleaning condition are used to intelligently judge whether the cleaning effect has reached the platform or is completed, so that more efficient end-stage cleaning strategy can be executed or the cleaning can be directly stopped, resource waste is avoided, and the cleaning efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0041] Figure 1 A flow chart of an automatic cleaning control method of a horizontal centrifuge provided by an embodiment of the present application;

[0042] Figure 2 An example diagram of a horizontal centrifuge provided by an embodiment of the present application;

[0043] Figure 3An example of a desorption index determination process is provided for an embodiment of the present invention.

[0044] Figure 2 Reference numerals in the drawings are designated as follows:

[0045] Feed inlet 1; heavy phase end 2; housing 3; discharge outlet 4; screw propeller 5; light phase end 6; power source 7; heavy phase end turbidity sensor 8; bowl 9; light phase end turbidity sensor 10; differential 11. DETAILED DESCRIPTION

[0046] In order to further clarify the technical means and effects taken by the present application to achieve the predetermined purposes, the following describes in detail the specific embodiments, structure, features and effects of the automatic cleaning control method of a horizontal centrifuge and the centrifuge according to the present application, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0048] The following describes in detail the specific scheme of the automatic cleaning control method of a horizontal centrifuge and the centrifuge provided by the present application.

[0049] Please refer to Figure 1 which shows the flowchart of the automatic cleaning control method of a horizontal centrifuge provided by an embodiment of the present application. The method comprises:

[0050] S101: periodically clean the horizontal centrifuge, and collect turbidity data of each cycle of heavy phase end and light phase end liquid discharge, wherein each cycle is preset with an upper limit value of the differential rotation speed of the screw propeller and the bowl.

[0051] It should be noted that, during the cleaning of the horizontal centrifuge, the bowl rotation speed is kept at the rated value, and the rotation speed of the screw propeller is controlled in a periodic manner, so as to periodically adjust the differential rotation speed of the screw propeller and the bowl, so as to form high-intensity disturbance through the change of the differential rotation speed, and realize the operation of cleaning the horizontal centrifuge.

[0052] It should be noted that the specific value of the rated rotation speed of the bowl is determined according to the actual situation, and the present embodiment does not make specific limitations, for example, the bowl rotation speed is set to 2500 rpm in the cleaning mode, and it can be found that the centrifugal force and the impact effect of the cleaning liquid are in the best balance state.

[0053] For example, the example diagram of the horizontal centrifuge is as shown in Figure 2As shown in the figure, wherein, the feed inlet 1, for input need centrifugal material and washing solution; heavy phase end 2, for output centrifugal after the solid component in the material, also can be used for discharge turbidity higher washing liquid when cleaning; machine shell 3, protect centrifugal force; discharge port 4, the material is input to the centrifuge drum; Spiral propeller 5, there is a certain difference between the rotational speed and the drum, can push the material in the inner wall of the drum to the heavy phase port; Light phase end 6, for output centrifugal after the liquid component in the material; Power source 7, provides centrifuge rotation power; Heavy phase end turbidity sensor 8, for detecting the turbidity of the liquid discharged from the heavy phase end when cleaning; Drum 9, provides centrifugal force, so that the heavy phase material is close to the inner wall of the drum; Light phase end turbidity sensor 10, for detecting the turbidity of the liquid discharged from the light phase end; Differential 11, for controlling the differential speed between the spiral propeller and the drum.

[0054] It should be noted that the specific time interval of the cycle is determined according to the actual situation, and the embodiment is not limited, for example, the time interval of the cycle is set to 150 seconds, and it can be found that each cycle can have good cleaning effect.

[0055] It should be understood that when the differential speed is in the state of increasing speed, the cleaning liquid will impact and strip off the large residual material, and if the differential speed is in the state of decreasing speed, the attached material will be loosened and shaken, and if the differential speed is in the state of stable speed, the residual material will be continuously washed and carried away, therefore, in order to achieve better dynamic cleaning effect, each cycle can be divided into three continuous differential speed control stages.

[0056] In the embodiment, in the first stage, the differential speed between the spiral propeller and the drum is controlled to gradually increase from the initial value to the upper limit value of the differential speed at a preset first rate; in the second stage, the differential speed is controlled to gradually fall from the upper limit value of the differential speed to the stable value at a preset second rate, wherein the stable value is less than or equal to the initial value; in the third stage, the differential speed is controlled to remain at the stable value until the next cycle.

[0057] It should be noted that the ratio of the duration of the first stage, the duration of the second stage and the duration of the third stage is a preset time ratio.

[0058] For example, in the cleaning mode, the drum speed is set to 2500 rpm (medium-high speed range), and each cycle is set to 150 seconds, wherein in the first stage (first 60 seconds), the differential speed gradually increases from the initial value (10 rpm) to the upper limit value (40 rpm) of the differential speed at a preset first rate (0.5 rpm per second), in the second stage (last 60 seconds), the differential speed gradually decreases from the upper limit value (40 rpm) of the differential speed to the stable value (8 rpm) at a preset second rate (0.5 rpm per second), and in the third stage (last 30 seconds), the differential speed is controlled to remain at the stable value (8 rpm).

[0059] It should be noted that the specific values of the differential rotation speed upper limit value, the initial value and the stable value are determined according to actual conditions, and the present embodiment is not specifically limited. For example, when the differential rotation speed upper limit value is set to 40 rpm, it can be found that there is no obvious increase in energy consumption and device wear due to excessively high rotation speed. When the initial value is set to 10 rpm, it can be found that the differential rotation speed is better increased to the differential rotation speed upper limit value. When the stable value is set to 8 rpm, it can be found that the cleaning liquid can better continuously flush and remove residues.

[0060] It should be noted that the specific value of the preset time ratio is determined according to actual conditions, and the present embodiment is not specifically limited. For example, when the preset time ratio is set to 2:2:1, the time required for impact stripping, oscillation loosening and stable flushing can be better balanced.

[0061] It should be noted that even for the same cycle, the residue carrying characteristics and turbidity data of different phase ends are different.

[0062] It should be understood that in actual operation, the distribution of residues inside the rotating drum has obvious spatial non-uniformity, especially near the heavy phase end, where a more obvious deposition zone is formed. In the first stage of the cycle, as the difference gradually accelerates, the mechanical disturbance generated in the first stage gradually increases, driving the contaminants attached to the inner wall of the rotating drum to gradually detach. However, since the propulsion intensity is still in the rising stage, the turbidity data of the heavy phase end discharge in the first stage cannot fully reflect the total amount of residue detachment in the entire cycle. Instead, in the subsequent second and third stages, the differential rotation speed gradually decreases, and since the residues have been sufficiently stripped, the cleaning liquid flows relatively stably at this time, mainly playing a carrying and discharging role. Therefore, the turbidity data of the heavy phase end discharge in the second and third stages can more truly reflect the overall effect of the cleaning action in the cycle.

[0063] It should be understood that compared with the heavy phase end, the liquid flow at the light phase end mainly flows along the center to the weir outlet, and the residue concentration carried by the discharge is usually low and relatively stable. However, as the cleaning process progresses, the turbidity of the light phase end discharge will gradually increase. Therefore, the turbidity data of the light phase end discharge in the first stage can be selected. In this stage, the residue concentration carried by the light phase end discharge is low, which can be well used as a contrast group to analyze the overall residue detachment effect in the corresponding cycle by analyzing the difference between the heavy phase end turbidity and the light phase end turbidity in the corresponding cycle.

[0064] In the embodiment, for each cycle, turbidity data of the heavy phase end effluent collected in the second stage and the third stage is taken as a first data set, and turbidity data of the light phase end effluent collected in the first stage is taken as a second data set; the first data set is arranged in ascending order of turbidity value to generate a first turbidity sequence; a subset greater than the upper quartile in the first turbidity sequence is extracted as first effective turbidity data of the heavy phase end; the second data set is arranged in ascending order of turbidity value to generate a second turbidity sequence; a subset less than the lower quartile in the second turbidity sequence is extracted as second effective turbidity data of the light phase end.

[0065] It should be noted that the specific way of calculating the upper quartile and the lower quartile is a technical means familiar to those skilled in the art, and will not be described here.

[0066] The first effective turbidity data represents part of the data with a larger turbidity value in the turbidity data of the heavy phase end effluent collected in the second stage and the third stage.

[0067] The second effective turbidity data represents part of the data with a smaller turbidity value in the turbidity data of the light phase end effluent collected in the first stage.

[0068] S102: For each cycle, according to the turbidity difference characteristics between the turbidity data of the heavy phase end and the turbidity data of the light phase end, determine a desorption index for quantifying the degree of desorption of the residual.

[0069] The desorption index determination process is as shown in Figure 3 , which includes:

[0070] S102-1: Calculate the average value of all turbidity values in the first effective turbidity data to obtain a first average value.

[0071] The first average value reflects the quantity of the relative concentration trend of each turbidity value in the first effective turbidity data.

[0072] S102-2: Calculate the average value of all turbidity values in the second effective turbidity data to obtain a second average value.

[0073] The second average value reflects the quantity of the relative concentration trend of each turbidity value in the second effective turbidity data.

[0074] S102-3: Take the difference between the first average value and the second average value as the desorption index.

[0075] Since, if the difference between the first average value and the second average value is large in a certain cycle, it indicates that there is a strong release and concentration of residual in the heavy phase end, then the cleaning effect in this cycle is better, and the degree of desorption of the residual is higher, therefore, the desorption index can be represented by the following formula:

[0076]

[0077] wherein, denotes the desorption index of the xth period; E denotes the mean value function; denotes the jth turbidity value in the first effective turbidity data; denotes the sth turbidity value in the second effective turbidity data; denotes the first average value; denotes the second average value; || denotes taking the absolute value.

[0078] S103: According to the desorption index change trend in the current period and the continuous N periods before the current period, determine the change index; if the change index is not less than the preset speed-up threshold, determine the difference speed adjustment coefficient according to the change index and the desorption index of the continuous N periods; based on the difference speed adjustment coefficient, adjust the difference speed upper limit value to obtain the target difference speed upper limit value, and update the difference speed upper limit value of all subsequent periods to the target difference speed upper limit value.

[0079] It needs to be understood that in the actual cleaning process, due to the influence of many factors such as instantaneous disturbance, local deposition structure, and cleaning liquid distribution, there may be short-term fluctuations or occasional abnormalities in the turbidity change in a single period. If the desorption index in the current period is used to adjust the differential speed, there is a risk of excessive response or strategy fluctuation. Therefore, in order to avoid using inappropriate differential speed to clean the centrifuge, thereby increasing energy consumption and wasting cleaning liquid, the desorption degree trend of continuous multiple periods can be analyzed to ensure that the turbidity data change is in the trend of smooth short-term fluctuations, and the stability and reliability of the control strategy are improved.

[0080] In the embodiment, the historical same period cleaning record is obtained, and the historical same period cleaning record includes the second average value of each historical period; for a time sequence composed of continuous N periods to the current period, for each period, the second average value of the historical period at the same sequence position as the ith period is extracted from the historical same period cleaning record; the maximum value of the second average value of the historical period is taken as the maximum second average value, wherein i=1, 2, …, N+1, i=N+1 corresponds to the current period; based on the second average value corresponding to the ith period and the maximum second average value, the desorption confidence of the ith period is obtained through a preset confidence calculation function; the desorption index in the current period and the continuous N periods is weighted linearly with the desorption confidence as the weight to obtain a fitting straight line, and the slope of the fitting straight line is taken as the change index.

[0081] The same sequence position indicates the position of the same sequence as i.

[0082] For example, the historical same period cleaning record of a cleaning horizontal centrifuge is obtained, the historical same period cleaning record includes each historical period and the second average value of each historical period, and it is assumed that 3 historical periods, i.e., the 1st historical period, the 2nd historical period and the 3rd historical period, are consumed for cleaning the centrifuge in the historical same period cleaning record, the second average value of the historical period in the same sequence position of the i-th period is extracted from the time sequence composed of the last N periods in the historical same period cleaning record, and the second average value of the 2nd historical period is extracted from the historical same period cleaning record if i is 2.

[0083] It should be noted that the specific value of N is determined according to actual needs, and the embodiment is not limited, for example, in the case of setting N as 7, the change trend of the desorption degree of the residual substance can be obviously judged.

[0084] It should be noted that the desorption index is calculated by analyzing the turbidity difference characteristics between the turbidity data of the heavy phase end and the turbidity data of the light phase end, and the turbidity data of the light phase end is used as a comparison group to explore the desorption degree of the residual substance in this process. However, due to the inconsistent turbidity change in different periods, the turbidity of the light phase end will change significantly, and the corresponding desorption index will be further affected by the sudden increase of the turbidity of the light phase end, thereby causing the misjudgment of the desorption degree of the residual substance in the later cleaning period. Therefore, the confidence degree can also be calculated by the desorption index of the light phase end, so as to analyze the reliability and accuracy of the predicted change index.

[0085] Since, if the second average value of the light phase end is smaller in a period, the difference between the second average value and the maximum second average value is larger, which indicates that the turbidity fluctuation of the light phase end is smaller, and the predicted change index is less affected by the turbidity change of the light phase end, then it also indicates that the predicted change index has high reliability. Therefore, the desorption confidence degree can be represented by the following preset confidence degree calculation function:

[0086]

[0087] wherein, represents the desorption confidence degree of the i-th period; , represents the second average value; represents the mean value function; represents the maximum second average value.

[0088] It should be noted that in the process of cleaning the centrifuge, the residues have not been completely stripped and discharged in the actual scene, so even in the earliest cycle, the light phase end liquid discharge contains a low concentration of residues, but still contains residues, and the light phase end will not have a turbidity value of zero at a certain moment, so, It will also be zero.

[0089] It should be understood that in order to clearly understand the change trend of the desorption index in the current cycle and the continuous N cycles before the current cycle, the least squares curve fitting method can be used to obtain a fitting function defined in the continuous set (the desorption index set in the current cycle and the continuous N cycles before the current cycle), that is, a fitting straight line.

[0090] In this embodiment, the starting time of the i-th cycle is obtained; the starting time of the i-th cycle is taken as the independent variable, and the desorption index of the i-th cycle is taken as the dependent variable. The desorption confidence is weighted, and the desorption index in the current cycle and the continuous N cycles is weighted linearly. The regression curve is obtained, and the least squares method is used to linearly fit the regression curve to obtain a fitting straight line.

[0091] It should be noted that the specific construction method of the regression curve is a technical means familiar to those skilled in the art, and this embodiment will not be repeated. For example, the function F of the regression curve can be represented as:

[0092]

[0093] wherein, represents the desorption index of the i-th cycle; represents the desorption confidence of the i-th cycle; represents the fitting value of the i-th cycle, wherein, ; represents the fitting value, which means that the regression coefficient is applied to the independent variable , so as to calculate the predicted value of the regression; represents the starting time of the i-th cycle; represents the regression constant; represents the regression coefficient.

[0094] It should be noted that, and The specific solution method of and is a technical means familiar to those skilled in the art, and this embodiment will not be repeated. For example, the unknown and can be obtained by using the least squares method.

[0095] It can be understood that the least squares method is used to linearly fit the regression curve F to obtain a fitting straight line, is the slope of the fitting straight line, then the slope determined by the least square method is is the change index.

[0096] It should be understood that if the desorption index gradually decreases over time, it reflects that the change of the desorption degree of the residues in the continuous multiple periods The trend of monotonic decrease or significant decrease in the decrease amplitude, i.e. the change index is small, indicates that the influence of the change of time on the change of the desorption degree of the residues is gradually decreasing, and at this time, the residues on the inner wall of the drum are less, and the cleaning intensity should be reduced; correspondingly, if the continuous multiple periods The fluctuation is large or there is no obvious downward trend, i.e. the change index is large, which indicates that there are still a large amount of residues that have not been desorbed from the inner wall of the drum, and the maximum difference rotational speed should be further increased.

[0097] It should be noted that the specific value of the preset speed-up threshold is determined according to the actual situation, and the present embodiment does not make specific limitations, for example, the preset speed-up threshold is set to 0, and it is found that the change trend of the desorption index in the continuous multiple periods can be well distinguished.

[0098] In order to accurately obtain the difference rotational speed adjustment coefficient, the smallest desorption index is selected from the desorption indexes of the continuous N periods; the difference between the desorption index of the current period and the smallest desorption index is calculated to obtain a first difference value; and the product of the first difference value and the change index is normalized to obtain the difference rotational speed adjustment coefficient.

[0099] The first difference value represents the difference between the desorption index of the current period and the smallest desorption index, and if the first difference value is larger, it reflects that the desorption index of the current period and the smallest desorption index have larger difference, which indicates that the desorption degree of the residues in the current period fluctuates greatly, and the difference rotational speed needs to be further increased, and then the difference rotational speed adjustment coefficient can be increased.

[0100] The difference rotational speed adjustment coefficient represents the adjustment degree of the upper limit value of the difference rotational speed.

[0101] Since, if the value is large, and the corresponding slope, i.e. the change index, is also large, it indicates that the adjustment degree of the upper limit value of the difference rotational speed needs to be increased, and then the value of the difference rotational speed adjustment coefficient in the subsequent period is also large, therefore, the target upper limit value of the difference rotational speed can be represented by the following formula:

[0102]

[0103] wherein, represents the preset upper limit value of the difference rotational speed in the current period; represents the difference rotational speed adjustment coefficient; represents the target upper limit value of the difference rotational speed.

[0104] S104: If the desorption indexes of the continuous M periods before the current period meet the end-stage cleaning condition, the rotation speed of the screw propeller is controlled to be synchronized with the rotation speed of the rotating drum and the weir height of the light phase overflow port is reduced in the current period.

[0105] It should be noted that the end-stage cleaning condition includes the existence of continuous M periods, and at the same time, M is not more than the preset first period threshold, and the desorption indexes of each period in the continuous M periods are all less than the preset desorption threshold.

[0106] It should be noted that the specific value of the preset first period threshold is determined according to the actual situation, and the embodiment is not limited, for example, the preset first period threshold is a positive integer, and the value range of the preset first period threshold is 3-5.

[0107] It should be noted that the specific value of the preset desorption threshold is determined according to the actual situation, and the embodiment is not limited, for example, in the case that the value of the preset desorption threshold is 0.05, it is found that the desorption degree of the residual material on the rotating drum and the screw propeller in the corresponding period is high, and the residual material has been roughly detached.

[0108] It should be understood that in the stage of the end-stage cleaning, although the turbidity of the whole drainage is low, the residual material of a certain concentration may still remain in the area near the overflow port of the light phase, which may be difficult to be completely carried out due to insufficient flow rate or limited flow of the cleaning liquid. Therefore, in the end-stage cleaning stage, the end-stage cleaning strategy of controlling the rotation speed of the screw propeller to be synchronized with the rotation speed of the rotating drum and the end-stage cleaning strategy of reducing the weir height of the light phase overflow port are executed, so as to form a more symmetrical and stable liquid flow distribution, so that more cleaning liquid is actively discharged from the light phase end, and the residual residual material is carried out.

[0109] S105: If the desorption indexes of the continuous T periods before the current period meet the stop cleaning condition, the cleaning is stopped in the current period, and the centrifuge is converted to a dehydration mode, wherein N, M and T are positive integers, N≥2, and T is greater than M.

[0110] It should be noted that the stop cleaning condition includes the existence of continuous T periods, and at the same time, T is not less than the preset second period threshold, and the desorption indexes of each period in the continuous T periods are all less than the preset desorption threshold, wherein the preset second period threshold is greater than the preset first period threshold.

[0111] It should be noted that the specific value of the preset second period threshold is determined according to the actual situation, and the embodiment is not limited, for example, the preset second period threshold is a positive integer, and the value range of the preset second period threshold is 6-8.

[0112] In the dewatering mode, in order to prevent material layer disturbance caused by sudden change of differential rotation speed from high differential rotation speed to low differential rotation speed, firstly, the differential rotation speed between the screw propeller and the drum is gradually faded to the dewatering working interval; next, the strength of the centrifugal force field is increased in steps; then, in order to maintain the stability of the pressure in the drum, the light phase end liquid discharge valve is closed, and the light phase end liquid discharge valve is switched to a pulse mode; finally, the dewatering effect is monitored in real time, and when the dewatering effect meets the expected effect, it is determined that the dewatering is completed.

[0113] One embodiment of the present application provides a horizontal centrifuge, which comprises a memory, a processor and a computer program stored in the memory and running on the processor, and the processor implements the steps of the automatic cleaning control method of the horizontal centrifuge when executing the computer program.

[0114] It should be noted that the above-mentioned sequence of the embodiments of the present application is only for description, and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or can be advantageous.

[0115] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment mainly describes the difference from other embodiments.

Claims

1. An automated cleaning control method for a horizontal centrifuge, characterized by, The method comprises: Periodically cleaning the horizontal centrifuge, collecting the turbidity data of the heavy phase end and the light phase end of each cycle, wherein the upper limit value of the differential speed of the screw propeller and the drum is preset for each cycle; For each cycle, the desorption index for quantifying the degree of desorption of the residual material is determined according to the turbidity difference between the turbidity data of the heavy phase end and the turbidity data of the light phase end; According to the change trend of the desorption index in the current cycle and the continuous N cycles before the current cycle, a change index is determined; if the change index is not less than a preset speed-up threshold, a differential speed adjustment coefficient is determined according to the change index and the desorption index of the continuous N cycles; based on the differential speed adjustment coefficient, the upper limit value of the differential speed is adjusted to obtain a target upper limit value of the differential speed, and the upper limit value of the differential speed of all subsequent cycles is updated to the target upper limit value of the differential speed; If the desorption index of the continuous M cycles before the current cycle meets the end cleaning condition, the speed of the screw propeller and the speed of the drum are kept synchronous and the weir height of the light phase overflow port is reduced in the current cycle; If the desorption index of the continuous T cycles before the current cycle meets the stop cleaning condition, the cleaning is stopped in the current cycle, and the centrifuge is converted to a dewatering mode, wherein N, M and T are positive integers, N≥2, and T is greater than M; Wherein each cycle includes three continuously performed differential speed control stages, the method comprises: In the first stage, the differential speed of the screw propeller and the drum is gradually increased from an initial value to an upper limit value of the differential speed at a preset first rate; In the second stage, the differential speed is gradually decreased from the upper limit value of the differential speed to a stable value at a preset second rate, wherein the stable value is less than or equal to the initial value; In the third stage, the differential speed is kept at the stable value until the next cycle; The method further comprises: For each cycle, the turbidity data of the heavy phase end is collected as a first data set in the second and third stages, and the turbidity data of the light phase end is collected as a second data set in the first stage; The first data set is arranged in ascending order of turbidity value to generate a first turbidity sequence; a subset greater than the upper quartile in the first turbidity sequence is extracted as the first effective turbidity data of the heavy phase end; The second data set is arranged in ascending order of turbidity value to generate a second turbidity sequence; a subset less than the lower quartile in the second turbidity sequence is extracted as the second effective turbidity data of the light phase end; The differential speed adjustment coefficient determination process comprises: Selecting the smallest desorption index from the desorption index of the continuous N cycles; Calculating the difference between the desorption index of the current cycle and the smallest desorption index to obtain a first difference value; The product of the first difference value and the change index is normalized to obtain the differential speed adjustment coefficient.

2. The method of claim 1, wherein the method further comprises: The desorption index determination process comprises: Calculating the average value of all turbidity values in the first effective turbidity data to obtain a first average value; Calculating the average value of all turbidity values in the second effective turbidity data to obtain a second average value; The difference between the first average value and the second average value is taken as the desorption index.

3. The method of claim 1, wherein the method further comprises: The change index determination process comprises: Obtaining historical concurrent cleaning records, the historical concurrent cleaning records including the second average value of each historical cycle; For a time sequence composed of the current period and N continuous previous periods, for each period, a second average value of a historical period corresponding to a same sequence position as the i-th period is extracted from historical cleaning records of a same period; a maximum of the second average values of the historical periods is taken as a maximum second average value, where i=1, 2, …, N+1, i=N+1 corresponds to the current period; Based on the second average value corresponding to the i-th period and the maximum second average value, a desorption confidence of the i-th period is obtained through a preset confidence calculation function; A fitting straight line is obtained by performing weighted linear regression on the desorption indicators in the current period and the N continuous previous periods with the desorption confidence as a weight, and a slope of the fitting straight line is taken as a change indicator.

4. The method of claim 3, wherein the method further comprises: The obtaining of the fitting straight line by performing the weighted linear regression on the desorption indicators in the current period and the N continuous previous periods with the desorption confidence as the weight includes: An initial time of the i-th period is obtained; A regression curve is obtained by performing weighted linear regression on the desorption indicators in the current period and the N continuous previous periods with the desorption confidence as a weight and the initial time of the i-th period as an independent variable, and a fitting straight line is obtained by performing linear fitting on the regression curve through a least square method.

5. The method of claim 1, wherein the method further comprises: The end cleaning condition includes that there are M continuous periods, and simultaneously, M is not more than a preset first period number threshold, and the desorption indicators of the M continuous periods are all less than a preset desorption threshold.

6. The method of claim 5, wherein the method further comprises: The stop cleaning condition includes that there are T continuous periods, and simultaneously, T is not less than a preset second period number threshold, and the desorption indicators of the T continuous periods are all less than the preset desorption threshold, where the preset second period number threshold is greater than the preset first period number threshold.

7. A horizontal centrifuge, characterized by The centrifuge includes a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the method according to any one of claims 1-6 when executing the computer program.

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