Mixture trough material level control method

Abstract

The invention discloses a mixture trough material level control method which comprises the following steps: acquiring a current material level value and a material level value at a previous moment; the preset material level interval where the current material level is located is judged, and the material level change rate is calculated according to the current material level value and the material level value at the previous moment; selecting a preset adjustment strategy according to the preset material level interval and the material level change rate of the current material level value; the comprehensive feeding amount is controlled according to the selected adjustment strategy; delaying the time; and repeating the steps. According to the invention, the defects of lagging and frequent adjustment of material level adjustment in the mixing trough can be prevented.

Description

Technical Field

[0001] The invention relates to the technical field of material level control of a mixing tank, and in particular to a material level control method of a mixing tank. Background Art

[0002] The mixing trough is a buffer trough before the sintering mixed raw materials enter the sintering machine trolley. It is installed at the head of the sintering machine as a buffer feeding device for distributing materials to the sintering machine. The mixed material is transported to the entrance of the mixing trough by a belt conveyor, and then distributed into the mixing trough by a shuttle distributor. At the outlet of the mixing trough, the material is evenly distributed on the sintering machine trolley through round rollers and nine rollers. The unstable material level of the mixing trough will affect the continuity of sintering. When the material level is too high, it will affect the operation of the mixing system. When the material level is too low, it will affect the operation of the sintering machine, thereby affecting the output and quality. Maintaining a certain material level stability in the mixing trough is conducive to stable feeding to the sintering machine and stabilizing the entire sintering production. Therefore, it is very important to realize automatic control of the material level of the mixing trough.

[0003] Usually, the high and low material levels are set directly, and the comprehensive feeding amount is increased or decreased according to the height of the material level. Since it takes about 15 to 20 minutes to transport the material from the batching site to the mixing tank, the distribution in this way will delay the adjustment process.

[0004] In the prior art, a fuzzy control threshold is also used to control the material level balance of a mixing tank. However, the size of the fuzzy control threshold is difficult to adapt to various situations, which easily leads to frequent adjustments.

[0005] In summary, how to prevent the lag and frequent adjustment of the material level in the mixing tank is one of the important issues to be solved in this field. Summary of the invention

[0006] The object of the present invention is to provide a material level control method for a mixing tank to solve the deficiencies in the prior art and to prevent the defects of delayed and frequent adjustment of the material level in the mixing tank.

[0007] The present invention provides a mixing tank material level control method, which comprises the following steps:

[0008] Get the current material level value and the material level value at the previous moment;

[0009] Determine the preset material level interval where the current material level is located, and calculate the material level change rate based on the current material level value and the material level value at the previous moment;

[0010] Select the preset adjustment strategy according to the preset material level interval and material level change rate where the current material level value is located;

[0011] Control the comprehensive feeding amount according to the selected adjustment strategy;

[0012] Delay and repeat the above steps.

[0013] In the mixing tank material level control method as described above, optionally, the number of preset material level intervals is at least 3.

[0014] In the mixing tank material level control method as described above, optionally, there are 5 preset material level intervals, which are, in order from small to large, the first preset material level interval, the second preset material level interval, the third preset material level interval, the fourth preset material level interval and the fifth preset material level interval; wherein the third preset material level interval is the target interval.

[0015] In the above-mentioned mixing tank material level control method, optionally, the preset adjustment strategy includes:

[0016] When the current material level is in the first preset material level interval:

[0017] If the material level change rate is less than 0, increase the comprehensive feeding amount according to the first adjustment amount;

[0018] If the material level change rate is not less than 0 and less than the first set value, the comprehensive feeding amount is increased according to the second adjustment amount;

[0019] If the material level change rate is not less than the first set value, the comprehensive loading amount is kept unchanged;

[0020] When the current material level is in the second preset material level interval:

[0021] If the material level change rate is less than the second set value, the comprehensive feeding amount is increased according to the first adjustment amount;

[0022] If the material level change rate is greater than the third set value, the comprehensive feeding amount is reduced according to the third adjustment amount;

[0023] If the material level change rate is between the second set value and the third set value, the comprehensive loading amount is kept unchanged;

[0024] When the current material level is in the third preset material level interval:

[0025] Control the comprehensive feeding amount according to the size relationship between the current material level and the middle value of the first preset material level and the material level change rate;

[0026] When the current material level is in the fourth preset material level interval:

[0027] If the material level change rate is less than the fourth set value, the comprehensive feeding amount is increased according to the fourth adjustment amount;

[0028] If the material level change rate is greater than the fifth set value, the comprehensive loading amount is reduced according to the fifth adjustment amount;

[0029] If the material level change rate is between the fourth set value and the fifth set value, the comprehensive loading amount remains unchanged;

[0030] When the current material level is in the fifth preset material level interval:

[0031] If the material level change rate is greater than 0, reduce the comprehensive feeding amount according to the sixth adjustment amount;

[0032] If the material level change rate is between the sixth set value and 0, the comprehensive feeding amount is reduced according to the seventh adjustment amount;

[0033] If the material level change rate is less than the sixth set value, the comprehensive loading amount remains unchanged.

[0034] The material level control method of the mixing tank as described above, wherein, optionally, when the current material level is in the third preset material level interval;

[0035] If the current material level is greater than the middle value of the third preset material level interval, and the material level change rate is greater than the seventh set value, the comprehensive loading amount is reduced according to the fourth adjustment amount;

[0036] If the current material level is less than the middle value of the third preset material level interval and the material level change rate is less than the eighth set value, the comprehensive loading amount is increased according to the fourth adjustment amount.

[0037] In the above-mentioned mixing tank material level control method, optionally, the five preset material level intervals are divided by four set material level division thresholds; and the four set material level division thresholds are, from small to large, the first division threshold Level_LL, the second division threshold Level_L, the third division threshold Level_H and the fourth division threshold Level_HH;

[0038] Among them, the first adjustment amount is: Level_L-LI current -LI △ *60;

[0039] The second adjustment amount is: Level_L-Level_LL;

[0040] The third adjustment amount is: LI current -Level_L+LI △ *60;

[0041] The fourth adjustment is: -LI △ *60;

[0042] The fifth adjustment amount is: -(LI current -Level_H+LI △ *60);

[0043] The sixth adjustment amount is: -(LI current-Level_HH+LI △ *60);

[0044] The seventh adjustment amount is: -(Level_HH-Level_H);

[0045] The first setting value is: (Level_LL-LI current ) / T;

[0046] The second setting value is: current -Level_LL) / T;

[0047] The third setting value is: (Level_L+(Level_H-Level_L) / 2-LI current ) / T;

[0048] The fourth setting value is: current -Level_L+(Level_H-Level_L) / 2) / T;

[0049] The fifth setting value is: (Level_HH-LI current ) / T;

[0050] The sixth setting value is: -(LI current -Level_HH) / T;

[0051] The seventh setting value is: (Level_H-LI current ) / T;

[0052] The eighth setting value is: -(LI current -Level_L) / T;

[0053] Among them, LI current is the current material level value, LI △ is the material level change rate.

[0054] In the above-mentioned mixing tank material level control method, optionally, the delay step includes:

[0055] The judgment is whether the comprehensive feeding amount has changed, if yes, delay according to the first time; if no, delay according to the second time;

[0056] The first time length is the time required for the material to be transported from the batching place to the mixing tank.

[0057] The mixing tank material level control method as described above, wherein, optionally, the second time is 3 to 6 seconds.

[0058] In the mixing tank material level control method as described above, optionally, the time difference between the current material level value and the material level value at the previous moment is 1 minute.

[0059] In the above-mentioned mixing tank material level control method, optionally, the material level change rate is calculated as follows:

[0060] LI △ =Buffer_Lev

[11] -Buffer_Lev[0];

[0061] Among them, Buffer_Lev

[11] is the current material level value, and Buffer_Lev[0] is the material level value of the previous unit time; △ is the material level change rate.

[0062] Compared with the prior art, the present invention utilizes a control method combining the current material level and the change rate of the mixing tank, that is, through the current material level and the material level change rate, the material level change that is about to occur according to the current state can be sensed in advance. Therefore, by controlling the material level through the current material level and the material level change rate, when the material level is about to have a large deviation but has not yet occurred, the large deviation that is about to occur can be eliminated by controlling the comprehensive feeding amount. According to this feeding method, the feeding amount can be adjusted in advance and adjusted according to the actual production requirements, avoiding frequent adjustment of the feeding amount, thereby ensuring that the material level is stable within the required range. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a flow chart of the overall steps of the present invention;

[0064] Figure 2 It is a flow chart of data processing steps in a specific application of the present invention;

[0065] Figure 3 It is a flow chart of the delay steps proposed by the present invention. DETAILED DESCRIPTION

[0066] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but should not be construed as limiting the present invention.

[0067] Example 1

[0068] Please refer to Figure 1 and Figure 2 This embodiment proposes a mixing tank material level control method, which includes the following steps:

[0069] S1, obtain the current material level value and the material level value at the previous moment. In the specific implementation, the current material level value is obtained by reading the detection result of the weighing material level sensor, which is recorded as LI in the present invention. current; The material level change rate is obtained by calculation and is recorded as LI △ , the unit is t / min, that is, the difference between the current material level value and the material level value one minute ago. Of course, it can also be the difference between the current material level value and the material level value before other time periods. In specific applications, the detected material level value can be stored in the data buffer at set intervals, where the data buffer is recorded as Buffer_Lev; it is a string containing multiple data. For example, when the material level value at the previous moment is the material level value one minute ago, there are 12 data in the data buffer, which correspond to the material level values ​​1 minute ago, 55 seconds ago, 50 seconds ago, 45 seconds ago, 40 seconds ago, 35 seconds ago, 30 seconds ago, 25 seconds ago, 20 seconds ago, 15 seconds ago, 10 seconds ago, 5 seconds ago and the current material level value, which are recorded as Buffer_Lev[0], Buffer_Lev[1], Buffer_Lev[2], Buffer_Lev[3], Buffer_Lev[4], Bu Buffer_Lev[5], Buffer_Lev[6], Buffer_Lev[7], Buffer_Lev[8], Buffer_Lev[9], Buffer_Lev

[10] , Buffer_Lev

[11] ; and, when a new current material level value is obtained, the original data in Buffer_Lev[0] is deleted, and the data in Buffer_Lev[1] is stored in Buffer_Lev[0], and the data in Buffer_Lev[2] is stored in Buffer_Lev[3]. The data is stored in Buffer_Lev[1], the data in Buffer_Lev[3] is stored in Buffer_Lev[2], the data in Buffer_Lev[4] is stored in Buffer_Lev[3], the data in Buffer_Lev[5] is stored in Buffer_Lev[4], the data in Buffer_Lev[6] is stored in Buffer_Lev[5], the data in Buffer_Lev[7] is stored in Buffer_Lev[6], the data in Buffer_Lev[8] is stored in Buffer_Lev[7], the data in Buffer_Lev[9] is stored in Buffer_Lev[8], the data in Buffer_Lev

[10] is stored in Buffer_Lev[9], the data in Buffer_Lev

[11] is stored in Buffer_Lev

[10] , and the newly acquired current material level value is stored in Buffer_Lev

[11] ; so that each data has a corresponding relationship with the above-mentioned each moment.

[0070] S2, determine the preset material level interval where the current material level is located, and calculate the material level change rate according to the current material level value and the material level value at the previous moment. In specific implementation, step S2 includes two steps, namely, S21, determine the preset material level interval where the current material level is located; S22, calculate the material level change rate according to the current material level value and the material level value at the previous moment. In specific application, there is no necessary order requirement between step S21 and step S22.

[0071] In the specific implementation, the preset material level interval where the current material level is located is determined, that is, the preset material level interval in which the current material is located is determined. According to the current material level value and the material level value at the previous moment, the material level change rate is calculated, which is: LI △ =(Buffer_Lev

[11] -Buffer_Lev[0]) / T jg ; Among them, T jg is the time interval between the current material level value and the material level value at the previous moment. In some cases, for example, when the time interval between the current material level value and the material level value at the previous moment is 1 minute, the calculation formula of the material level change rate can also be recorded as LI △ = Buffer_Lev

[11] -Buffer_Lev[0], the unit is t / min. When the current material level is on an upward trend, LI △ >0, when the current material level is in a downward trend, LI △ <0;

[0072] LI current =Buffer_Lev

[11] ;

[0073] WT=LI △ *60+WT △ , WT △ To ensure that the final material level is stable in the target material level range, the amount of adjustment is made based on the specific situation to ensure the balance, so that the material level moves to the target material level range. Different material level values, WT △ The target material level interval is one of the preset material level intervals, usually the one in the middle of the preset material level interval. When setting the control program, you can press Figure 2 The data is acquired and processed according to the flowchart in the figure.

[0074] S3, select the preset adjustment strategy according to the preset material level interval and the material level change rate where the current material level value is located; this step is one of the key steps of the present invention. The preset adjustment strategy corresponds to the division of the preset material level interval. The adjustment strategy is different according to the number of preset material level intervals and the range of each interval.

[0075] In a specific implementation, the number of preset material level intervals is at least 3. In a specific implementation, when the target material level interval and the three preset material level intervals are arranged in order from small to large or from large to small, the preset material level interval in the middle.

[0076] S4, controlling the comprehensive loading amount according to the selected adjustment strategy; in specific implementation, multiple adjustment strategies can be stored according to the corresponding relationship. When in use, the corresponding adjustment strategy is extracted according to the preset material level interval and the material level change rate corresponding to the current material level, and the comprehensive loading amount is controlled according to the adjustment strategy. In specific implementation, the adjustment amount of the comprehensive loading amount is set according to the corresponding preset material level interval and the material level change rate.

[0077] S5, delay; in order to avoid repeated adjustment too frequently, the present invention sets a delay step, specifically, please refer to Figure 3 , the delay steps include:

[0078] The judgment is whether the comprehensive feeding amount has changed. If yes, the delay is based on the first time; if not, the delay is based on the second time; wherein the first time length is the time required for the material to be transported from the batching place to the mixing tank. In specific implementation, the first time length is 15 to 20 minutes. Preferably, the first time length is the time required for the material to be transported from the batching place to the mixing tank. The second time length is the set time interval for collecting the current material level value, which can be 3 seconds, 4 seconds, 5 seconds, 6 seconds, etc. Preferably, 5 seconds is selected.

[0079] S6, repeat the above steps S1-S5. That is, in the working state, the above steps S1 to S5 are continuously repeated to adjust the material level.

[0080] Through delayed operation, after each adjustment, it is necessary to wait for T before making another judgment and adjustment. T is the time it takes for the material to reach the mixing silo from the batching point. This cycle is repeated to achieve automatic control of the material level in the mixing trough.

[0081] Embodiment 2,

[0082] This embodiment is a further improvement on the basis of the embodiment 1, and the similarities are not repeated here, and only the differences are improved below.

[0083] Specifically, considering the accuracy and complexity of control, the number of preset material level intervals is preferably 5.

[0084] That is, there are 5 preset material level intervals, and they are the first preset material level interval, the second preset material level interval, the third preset material level interval, the fourth preset material level interval and the fifth preset material level interval in order from small to large; among which, the third preset material level interval is the target interval. When setting, the 5 preset material level intervals cover the entire material level value range, and there is no intersection between any two preset material level intervals.

[0085] In order to adapt to the five preset material level intervals, this embodiment proposes the following adjustment strategies:

[0086] (1) When the current material level is in the first preset material level interval: at this time, the current material level is low;

[0087] If the material level change rate is less than 0, increase the comprehensive feeding amount according to the first adjustment amount; at this time, the material level is in a downward trend, and the comprehensive feeding amount should be increased.

[0088] If the material level change rate is not less than 0 and less than the first set value, the comprehensive feeding amount is increased according to the second adjustment amount; at this time, the material level is in an upward trend, but the material level rises slowly, and the comprehensive feeding amount should be slightly increased.

[0089] If the material level change rate is not less than the first set value, the comprehensive feeding amount is kept unchanged; at this time, although the material level is at a lower position, the material level change becomes larger and is on an upward trend, and the comprehensive feeding amount does not need to be adjusted.

[0090] (2) When the current material level is in the second preset material level interval: At this time, the current material level is slightly lower than the minimum value of the target interval;

[0091] If the material level change rate is less than the second set value, increase the comprehensive feeding amount according to the first adjustment amount; at this time, the material level is low, and the material level is in a downward trend or the rising speed is too slow, and the material level decreases at a large speed, so the comprehensive feeding amount should be increased.

[0092] If the material level change rate is greater than the third set value, the comprehensive feeding amount is reduced according to the third adjustment amount; at this time, the material level is on an upward trend and the material level change rate is large, so the comprehensive feeding amount should be increased.

[0093] If the material level change rate is between the second set value and the third set value, the comprehensive loading amount is kept unchanged; at this time, the material level is in a slowly increasing trend, and the current comprehensive loading amount is kept unchanged.

[0094] (3) When the current material level is in the third preset material level interval: At this time, the current material level is in the target material level interval, and further precise control can be performed as needed;

[0095] When further precise control is required, the comprehensive material loading amount is controlled according to the relationship between the current material level and the intermediate value of the first preset material level and the material level change rate.

[0096] (4) When the current material level is in the fourth preset material level interval: at this time, the material level is high;

[0097] If the material level change rate is less than the fourth set value, at this time, the material level change rate is in a decreasing trend, and the decreasing speed is too fast, then the comprehensive feeding amount is increased according to the fourth adjustment amount.

[0098] If the material level change rate is greater than the fifth set value, at this time, the material level change rate is in an upward trend, and the increasing speed is too fast, then the comprehensive feeding amount is reduced according to the fifth adjustment amount.

[0099] If the material level change rate is between the fourth setting value and the fifth setting value, the material level change is slowly decreasing, and the comprehensive loading amount remains unchanged.

[0100] (5) When the current material level is in the fifth preset material level interval: at this time, the material level is too high;

[0101] If the material level change rate is greater than 0, at this time, the material level is too high and continues to rise, and the comprehensive feeding amount is reduced according to the sixth adjustment amount;

[0102] If the material level change rate is between the sixth set value and 0, at this time, although the material level is decreasing, the decreasing speed is too slow, and the comprehensive feeding amount is reduced according to the seventh adjustment amount.

[0103] If the material level change rate is less than the sixth set value, at this time, the material level drops rapidly, and the comprehensive feeding amount remains unchanged.

[0104] In specific implementation, when the current material level is in the third preset material level interval; in order to achieve more precise control of the material level, this embodiment also makes the following improvements:

[0105] If the current material level is greater than the middle value of the third preset material level interval, and the material level change rate is greater than the seventh set value, the comprehensive loading amount is reduced according to the fourth adjustment amount. At this time, the current material level is within the target range, slightly higher, but the material level change is on an upward trend. At this time, the comprehensive loading amount should be slightly reduced.

[0106] If the current material level is less than the middle value of the third preset material level interval, and the material level change rate is less than the eighth set value, the comprehensive feeding amount is increased according to the fourth adjustment amount. At this time, the current material level is in the target interval, slightly lower, but the material level change is in a downward trend. At this time, the comprehensive feeding amount should be slightly increased.

[0107] When the material level is in the third preset material level interval, except for the above two situations, the comprehensive loading amount is kept unchanged. In specific implementation, the optimal material level value should be the middle value of the third preset material level interval.

[0108] In one implementation, the entire range of the material level can be divided by several dividing thresholds, thereby obtaining multiple preset material level intervals. Specifically, the five preset material level intervals are divided by four set material level dividing thresholds; and the four set material level dividing thresholds are, from small to large, the first dividing threshold Level_LL, the second dividing threshold Level_L, the third dividing threshold Level_H and the fourth dividing threshold Level_HH. Specifically, the optimal material level value is (Level_H+Level_L) / 2.

[0109] According to the above classification, the first adjustment amount, the second adjustment amount, the third adjustment amount, the fourth adjustment amount, the fifth adjustment amount, the sixth adjustment amount, and the seventh adjustment amount in this embodiment are the amounts for increasing or decreasing the comprehensive loading amount; the first set value, the second set value, the third set value, the fourth set value, the fifth set value, the sixth set value, the seventh set value, and the eighth set value are the thresholds of the material level change rate in the control logic. For this group of set values, the patent of the present invention uses the material level threshold and the current real-time material level to calculate, that is, the result changes with the current material level. Compared with using a fixed set threshold, the present invention can avoid the situation where the adjustment has not been triggered due to a small change in the amount and the threshold has not been exceeded. Specifically:

[0110] The first adjustment amount is: Level_L-LI current -LI △ *60;

[0111] The second adjustment amount is: Level_L-Level_LL;

[0112] The third adjustment amount is: LI current -Level_L+LI △ *60;

[0113] The fourth adjustment is: -LI △ *60;

[0114] The fifth adjustment amount is: -(LI current -Level_H+LI △ *60);

[0115] The sixth adjustment amount is: -(LI current -Level_HH+LI △ *60);

[0116] The seventh adjustment amount is: -(Level_HH-Level_H);

[0117] The first setting value is: (Level_LL-LI current ) / T;

[0118] The second setting value is: current -Level_LL) / T;

[0119] The third setting value is: (Level_L+(Level_H-Level_L) / 2-LI current ) / T;

[0120] The fourth setting value is: current-Level_L+(Level_H-Level_L) / 2) / T;

[0121] The fifth setting value is: (Level_HH-LI current ) / T;

[0122] The sixth setting value is: -(LI current -Level_HH) / T;

[0123] The seventh setting value is: (Level_H-LI current ) / T;

[0124] The eighth setting value is: -(LI current -Level_L) / T;

[0125] Among them, LI current is the current material level value, LI △ It should be noted that due to the different intervals of the current material level value, the final calculation results of the same set value or the same change in different intervals may be different, and their positive and negative signs may also be different.

[0126] Through the above-mentioned Example 1 and Example 2, the present invention uses a control method that combines the current material level correction value of the mixing tank and the material level change rate to realize the control of the material level of the mixing tank. The whole control idea is to judge whether it will change to another preset material level interval after time T (the time for the material from the batching system to the mixing tank) according to the calculated material level change rate based on the preset material level interval where the current material level is located, and increase or decrease the comprehensive feeding amount in advance before the material level changes to another material level interval according to production requirements. The preset material level interval is set according to production requirements, and the interval threshold of the material level change rate is calculated using the current material level and the interval material level threshold in combination with the current material level change (increase or decrease), and changes in real time with the change of the current material level. According to such a control idea, it is possible to adjust the feeding amount in advance and adjust it according to the actual production requirements, avoiding frequent adjustment of the feeding amount, thereby ensuring that the material level is stable within a certain range.

[0127] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A method for controlling the material level of a mixing tank, Features: Get the current material level value and the material level value at the previous moment; Determine the preset material level interval where the current material level is located, and calculate the material level change rate based on the current material level value and the material level value at the previous moment; Select the preset adjustment strategy according to the preset material level interval and material level change rate where the current material level value is located; Control the comprehensive feeding amount according to the selected adjustment strategy; Delay; Repeat the above steps.

2. The mixing tank material level control method according to claim 1, Features: There are at least 3 preset material level intervals.

3. The mixing tank material level control method according to claim 2, Features: There are five preset material level intervals, which are, in ascending order, the first preset material level interval, the second preset material level interval, the third preset material level interval, the fourth preset material level interval and the fifth preset material level interval; wherein the third preset material level interval is the target interval.

4. The mixing tank material level control method according to claim 3, Features: The preset adjustment strategy includes: When the current material level is in the first preset material level interval: If the material level change rate is less than 0, increase the comprehensive feeding amount according to the first adjustment amount; If the material level change rate is not less than 0 and less than the first set value, the comprehensive feeding amount is increased according to the second adjustment amount; If the material level change rate is not less than the first set value, the comprehensive loading amount is kept unchanged; When the current material level is in the second preset material level interval: If the material level change rate is less than the second set value, the comprehensive feeding amount is increased according to the first adjustment amount; If the material level change rate is greater than the third set value, the comprehensive feeding amount is reduced according to the third adjustment amount; If the material level change rate is between the second set value and the third set value, the comprehensive loading amount is kept unchanged; When the current material level is in the third preset material level interval: Control the comprehensive feeding amount according to the size relationship between the current material level and the middle value of the first preset material level and the material level change rate; When the current material level is in the fourth preset material level interval: If the material level change rate is less than the fourth set value, the comprehensive feeding amount is increased according to the fourth setting; If the material level change rate is greater than the fifth set value, the comprehensive loading amount is reduced according to the fifth adjustment amount; If the material level change rate is between the fourth set value and the fifth set value, the comprehensive loading amount remains unchanged; When the current material level is in the fifth preset material level interval: If the material level change rate is greater than 0, reduce the comprehensive feeding amount according to the sixth adjustment amount; If the material level change rate is between the sixth set value and 0, the comprehensive feeding amount is reduced according to the seventh adjustment amount; If the material level change rate is less than the sixth set value, the comprehensive loading amount remains unchanged.

5. The mixing tank material level control method according to claim 4, Features: When the current material level is in the third preset material level interval; If the current material level is greater than the middle value of the third preset material level interval, and the material level change rate is greater than the seventh set value, the comprehensive loading amount is reduced according to the fourth adjustment amount; If the current material level is less than the middle value of the third preset material level interval and the material level change rate is less than the eighth set value, the comprehensive loading amount is increased according to the fourth adjustment amount.

6. The mixing tank material level control method according to claim 5, Features: The five preset material level intervals are divided by four set material level division thresholds; and the four set material level division thresholds are, from small to large, the first division threshold Level_LL, the second division threshold Level_L, the third division threshold Level_H and the fourth division threshold Level_HH; Among them, the first adjustment amount is: Level_L-LI current -LI △ *60; The second adjustment amount is: Level_L-Level_LL; The third adjustment amount is: LI current -Level_L+LI △ *60; The fourth adjustment is: -LI △ *60; The fifth adjustment amount is: -(LI current -Level_H+LI △ *60); The sixth adjustment amount is: -(LI current -Level_HH+LI △ *60); The seventh adjustment amount is: -(Level_HH-Level_H); The first setting value is: (Level_LL-LI current ) / T; The second setting value is: current -Level_LL) / T; The third setting value is: (Level_L+(Level_H-Level_L) / 2-LI current ) / T; The fourth setting value is: current -Level_L+(Level_H-Level_L) / 2) / T; The fifth setting value is: (Level_HH-LI current ) / T; The sixth setting value is: -(LI current -Level_HH) / T; The seventh setting value is: (Level_H-LI current ) / T; The eighth setting value is: -(LI current -Level_L) / T; Among them, LI current is the current material level value, LI △ is the material level change rate.

7. The mixing tank material level control method according to any one of claims 1 to 6, Features: The delay steps include: The judgment is whether the comprehensive feeding amount has changed, if yes, delay according to the first time; if no, delay according to the second time; The first time length is the time required for the material to be transported from the batching place to the mixing tank.

8. The mixing tank material level control method according to claim 7, Features: The second time is 3 to 6 seconds.

9. The mixing tank material level control method according to claim 7, Features: The time difference between the current material level value and the material level value at the previous moment is 1 minute.

10. The mixing tank material level control method according to claim 9, Features: The calculation formula of material level change rate is: LI △ =Buffer_Lev[11]-Buffer_Lev[0]; Among them, Buffer_Lev[11] is the current material level value, and Buffer_Lev[0] is the material level value of the previous unit time; △ is the material level change rate.

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