SU980832A1 - Method of controlling disintegration process in closed cycle type mill - Google Patents

Description

(5) METHOD OF MANAGING THE PROCESS OF GRINDING IN A MILL OF A CLOSED CYCLE

one

The invention relates to the automation of grinding processes and can be used in the cement, ceramic, metallurgical and other industries related to the processes of fine grinding of materials.

There is a known method for controlling the loading of a ball mill, including. changing the material feed to the mill depending on the load level by the signal of the extreme performance regulator, analyzing the mill overloads by measuring the mill load increments while reducing its performance, fixing the overloads when the allowable load level increments and eliminating 2o overloads by making increased steps towards reducing the consumption of the source material. P.

The disadvantage of this method is the high criticality of the efficiency of the control over the choice of the magnitude of the increased load step, which cannot be unambiguously established due to incomplete information about the object.

There is a known method for controlling the grinding process in a closed-cycle mill, which includes measuring the material consumption in the mill, the total load consumption and the finished product consumption, changing the material consumption in the mill depending on the set task and changes in the total load of the mill, changing the set task when regulating the flow of material into the mill, fixing emergency overloads and their prevention by temporary exclusion; kstremalnogo Ranging measurements

the rate of change in the flow rate of the finished product with the temporary exclusion of extreme control and the resumption of the extreme control after the transition time C 2.

The disadvantages of this method are the presence of significant losses in the search for maximum performance after completing the unloading step while eliminating emergency overloads and the lack of measures to reduce the number of emergency overloads, which leads to a decrease in the productivity of the mill. :

The purpose of the invention is to improve the accuracy of control.

This goal is achieved by the fact that according to the method of controlling the grinding process in a closed-cycle mill, including measuring the consumption of the material in the mill, the consumption of the total load and the consumption of the finished product, the change in the consumption of material in the mill, depending on the set task and the total load of the mill, extreme regulation mill performance by changing the set task when controlling the flow of material into the mill, fixing emergency overloads and their prevention by temporarily excluding extreme control, measuring the rate of change in the flow rate of the finished product, with BpeNjeHHOM eliminating extreme control and resuming extreme control after a transient time, with extreme regulation, the set task is fixed, at the time of reversing the direction of change, with temporary exclusion of extreme control, the sign is fixed the rate of change of consumption of the finished product and after the resumption of extreme regulation re-exclusion of extreme regulation is performed, and when resuming extreme regulation, the boundary setting of the material consumption is established depending on the total load and the finished product consumption measured at the moment of changing the sign of the rate of change of the finished product consumption, and the extreme regulation is repeated when the boundary reference is fixed task at the time of the reverse direction of the task change.

Based on the analysis of the transition process with the excluded extreme regulation, the boundary value of the task is determined, which, when the extreme regulation is resumed, reduces the search losses. Comparison of the task set at the time of the reversal of the direction of the task with the limit value, and the repeated exclusion of extreme regulation when the limit value of the task is exceeded, reduces the likelihood of emergency situations. Setting the boundary value of the task provides compensation for disturbances acting on the grinding process.

The control of the grinding process in a closed-cycle mill using the proposed method is carried out as follows.

The value is determined by the tasks of the material consumption in the mill during the initial activation (resumption) of extreme regulation depending on the averaged values of the maximum productivity of the mill and the value of the total load corresponding to the maximum performance at a known ratio of the magnitude of the change in the source material to the value of the change in the total load when controlling the material consumption in the mill (hereinafter this task value is called the boundary value).

Claims (2)

In this case, the averaged values of the maximum productivity and the magnitude of the total load corresponding to the maximum performance are determined in advance on the basis of an experimental study of the static characteristics of the mill or of an analytical calculation. For example, if the regulation of the material flow to the mill, depending on the set task, is proportional to the change in the total load, then the initial value of the target value is determined by summing the maximum performance value with the value of the corresponding total load, taken with the known proportionality factor, changes the material flow rate Depending on the magnitude of the task and changes in the total load, extreme regulation of the the duration of the mill by changing the task of material flow to the mill. For example, with extreme regulation, an increase in the total load occurs with an increase in the task of material consumption per mill. Then, with a non-JOTOPOM value of the task for the material consumption in the mill and total load, the conditions for reversing the direction of change of the task for the flow of the source material into the mill are fulfilled. temporarily excludes and measures the rate of change in the consumption of the finished product during a period of time due to the duration of the transition process. The ratio of material consumption to the mill and the total load at the moment of reversal conditions depends on the chosen method of extreme performance control (for example, step search for an extremum with analysis of the sign of the increment of productivity or continuous search of the extremum taking into account the sign of the first and second derivatives of the performance) static characteristic drifts. In the general case, the state of the mill at the time of reversal does not correspond to a stable equilibrium in the extremum of the static characteristic, i.e. this state of the object, in which the consumption of material in the mill is equal to the maximum productivity at the value of the total load corresponding to the maximum performance. Suppose that the value of the total load at the time of exclusion of the extreme control is less than the value corresponding to the maximum performance, and the value of the material consumption at the time of reaching the total load at the value of the task on material consumption recorded at the time of exclusion of the extreme control exceeds the maximum performance .. In this case the rate of change in the consumption of the finished product, measured during the transition process at the beginning, is positive and changes sign in m ment when the total load passed through the total load value corresponding to the maximum actual static characteristics of the object. The value of the total load and productivity at this moment is measured, the new current and equal to it boundary value of the task for the material flow to the mill is determined and set, and after a period of time due to the duration of the transition process, the extremal regulation of productivity is resumed. Similarly, the control is carried out in the case when the value of the total load at the time of exclusion of extreme regulation exceeds the value corresponding to the maximum performance, and the value of material consumption at the time of reaching this value of total loading at the value of the task on material consumption recorded at the moment of exclusion of extreme regulation , less than maximum performance. In the case when the rate of change in the consumption of the finished product during the transition process after exclusion of extreme regulation is sign-based and positive, the extreme regulation is resumed, and if the rate of change of consumption of the finished product during the period of time due to the duration of the transition process after exclusion of extreme control is signified and negative, analyze the presence of emergency overload by comparing the increment of the total load with the allowable By the reason, and if the increment of the total load is less than permissible, extreme regulation is resumed, and if the increment permissible value is exceeded, the presence of an emergency overload is predicted, the flow rate of the finished product is predicted for the time the material passes through the mill, the value of the material used in the mill. equal to the predicted consumption of the finished product and repeat all the operations associated with analyzing the rate of change of the finished product by adjusting the boundary value for the consumption of the starting material and resuming the extreme adjustment in the sequence outlined. The drawing shows a device that implements the method. The device contains the original shaft that enters the mill 1, mill 2, the total load coming from the mill to separator 3, se parator C, the product returned to the grinding unit (grains) 5, the finished product 6, the regulator, changing the flow rate of the initial charge 7. Flow sensor of the initial charge 8, flow sensor of the total load 9 finished product flow sensor 10, load controller 11, load control setpoint 12, emergency overload diagnostics unit 13, controlled switch 14, extreme controller 15, differentiator 16, n The terminal 17 sets the limit value setpoint to the load controller 18, the comparison block 19, the match block 20, the OR 21 block, the trigger 22, the job calculation block 23, the controlled multi-channel switch 2, controlled by KJB04 25, the job calculation block 26, the differentiator 27, the delay unit (time relay) 28, the zero-body 29. The device operates as follows. The initial charge 1 is crushed in the mill 2, from the sum of the mill, the load 3 enters the separator C, where it is divided into the coarse product 5 returned to the mill and the finished product 6. The change in the flow rate of the initial charge to the chili is made by the regulator. The costs of the initial charge, the total load and the finished product are changed respectively by sensors 8-10, the outputs of sensors 8 and 9 are connected to the inputs of the load controller 11, which changes the flow rate of the original charge using the regulator 7 depending on the changes in the total load flow and the task , the value of which is determined by the load control controller 12. The emergency overload diagnostics block 138 records the fact that there is an emergency overload of the mill based on the analysis of signals from the initial charge flow sensors, total load and finished product. In the initial state. To the input of the setting knob of the load controller 12 through the contacts of the controlled switch H are connected the output of the extreme controller 15, which searches for the maximum productivity of the mill. The differentiator 16 measures the rate of change of the task set by the setting device 12, and the null organ 17 records the moment of change of the sign of the rate of change of the task, i.e. moment of reversal of the extreme regulator. The position of the setting device 12 is compared with the boundary value of the task determined by the setting unit of the boundary value of task 18 using the comparison block 19. Output More comparison block 19 and the output of the null organ 17 are fed to the inputs of the match block 20, the output of which is connected to the first input of the OR 21 block. To the second input of the OR unit, the output of the diagnostics block for emergency overload 13 is connected. Thus, if an emergency overload is fixed or if two events coincide: reverse of the extreme regulator and overloading of the load regulator, compared to the setting of the reference from the block OR 21, a signal is sent to the first input of the trigger 22. When the state of the trigger 22 changes, the position of the controlled switch 1 changes, as a result of which the extreme regulator 15 is disconnected from the input of the setting unit 12, and the setting of the setting unit 12 is enabled. with the block for calculating the task 23 through the switch 24. In the event of an avalanche of the 1st overload, the key 25 closes and the input of the block for the calculation of the block 26, to the input of which the sensor outputs Yes, the total load 9 and the differentiator 27, which measures the rate of change of the finished product flow rate 10. Thus, fixing the emergency overload ensures that the set position of the load controller is set at which the flow rate of the batch charge to the mill is reached, equal to the predicted flow rate of the finished product. The second output of the trigger 22 through a no-time closed contact switch l 24 includes a delay unit 23, for example, a time relay, which starts counting the time delay corresponding to the duration of the transient process. The zero-body 29 fixes the moment of change of the sign of the rate of change in the consumption of the finished product measured by the differentiator. 2. The output of the zero-organ 29 is connected to a controlled multi-channel switch 2C. If for a period of time equal to the set duration of the transient process, the position of the switch 2k does not change, i.e. the rate of change of the finished product is sign-wise, then after a delay, the delay delay 28 moves the trigger 22 to another position and turns off, while the control switch C returns to its original state, thereby restarting extreme regulation. In the case when the rate of change of the finished product changes sign during the transition process, at the moment of changing the sign of speed, the null organ 29 changes the position of the multichannel switch 2, as a result of which the load control setpoint 12 and the limit value block 18 are connected by the flow of the calculation block of task 23 to the inputs of which are connected the outputs of the flow sensors of the total load and the flow rate of the finished product 10. At the same time, the value of the task to the load controller is set so that you in the mill at the total load measurement value is the measured value of the finished product and limit reference value is set equal to the set value specifying controller torus loading. At the same time, the contact of the switch 24 resets the delay unit 28, after which the transient time begins again. This method improves control accuracy. 2 10 The invention The method of controlling the grinding process in a closed-cycle mill, including measuring the material consumption per mill, total load flow rate and finished product flow rate, changing the material flow rate per mill depending on the set task and changes in the total mill load, extreme control of the mill productivity by changing set task in controlling the flow of material into the mill, fixing emergency leregruzku and their prevention by temporary eliminating extreme regulation, measuring the rate of change in the flow rate of the finished product with temporary elimination of extreme regulation, and resuming extreme regulation after the transition time, characterized in that, in order to improve the control accuracy, with extreme regulation, the set task is fixed at the time of reversing its direction of change , with the temporary exclusion of extreme regulation, determine the sign of the rate of change in the consumption of the finished product and After resuming extreme control, extreme control is re-excluded, and when extreme control is resumed, the boundary setting of material consumption is established depending on the total load and finished product flow measured at the moment of changing the sign of the change in the flow rate of the finished product, and re-excluding extreme control is performed at when the boundary task is exceeded by a fixed task at the moment of reversal of the direction of change of adani. Sources of information taken into account in the examination 1. The author's certificate of the USSR N 538736, cl. At 02 C 25/00, 1976, 2, USSR Copyright Certificate K 622497, cl. B 02 C 25/00, 1978 (prototype). one.