JP5277967B2 - Control method of vertical crusher - Google Patents

Description

  The present invention relates to a control method and a control apparatus for a vertical crusher that mainly uses coal, oil coke, limestone, slag, clinker, cement raw materials, or chemicals as raw materials, and in particular, the raw material in a vertical crusher The present invention relates to a control method and a control device for a vertical crusher suitable for preventing or suppressing abnormal vibrations that are likely to occur when finely pulverizing a powder.

  Conventionally, a crusher called a vertical crusher (sometimes called a vertical mill or a vertical roller mill) has been widely used as a crusher for crushing coal, oil coke or the like.

  In recent years, in particular, the number of cases in which raw materials are finely pulverized by a vertical pulverizer is increasing, and the number of vertical pulverizers having a classification mechanism in the vertical pulverizer is increasing. As a vertical grinder equipped with this classification mechanism, a conventional technique as disclosed in Patent Document 1 below is known.

Japanese Patent Laid-Open No. 5-104012

  The vertical pulverizer disclosed in this Patent Document 1 conveys and raises the pulverized raw material by an air flow blown from the lower part of the pulverizer, and by a classification mechanism arranged at the upper part in the vertical pulverizer, This is a vertical pulverizer of a type that selects only fine powder from the conveyed raw materials and takes it out of the apparatus, and is a type of vertical pulverizer generally called an air sweep type.

  Hereinafter, the structure of the air swept type vertical crusher disclosed in Patent Document 1 will be briefly described. The vertical crusher disclosed in Patent Document 1 includes a rotary separator having a plurality of rotary blades as a classification mechanism above a rotary table, and extends vertically through the central axis of the rotary separator. The material input chute is arranged. And it is comprised so that a raw material can be injected | thrown-in on a turntable from a raw material insertion port via a raw material injection | chute chute | shoot (it may be called supply).

  The raw material supplied to the central portion of the rotary table from above the rotary table by the raw material charging chute moves toward the outer peripheral portion of the rotary table while drawing a spiral trajectory on the rotary table. A dam ring is provided on the outer peripheral edge of the rotary table and is configured to maintain the required raw material thickness on the rotary table, so that the raw material that has moved to the outer periphery of the rotary table is blocked by the dam ring. Then, it is crushed by being bitten by the rotary table and the crushing roller.

  In addition, a part of the raw material that is pulverized by the rotary table and the crushing roller gets over the dam ring that is provided around the outer edge of the rotary table, and is a ring that is a gap between the outer peripheral portion of the upper surface of the rotary table and the casing. Head to the passage (sometimes called an annular space).

  During operation of the vertical pulverizer, gas is introduced into the vertical pulverizer from the gas inlet provided at the lower part of the pulverizer by a blower such as an exhaust fan, and the upper part of the pulverizer is It is discharged out of the machine through the take-out port. As a result, a gas flow from the lower side of the rotary table to the upper side of the rotary separator is generated in the casing of the vertical crusher. Accordingly, a part of the raw material that has reached the annular passage over the dam ring is blown up by the gas flow and rises in the casing.

  The airflow rising in the casing is an airflow rising while swirling under the influence of the blade effect provided in the rotary separator and the annular passage. Therefore, among the raw materials blown up by the airflow, the raw material having a large diameter and a large weight falls from the airflow due to the centrifugal force generated in the raw material itself due to the weight of the raw material falling below the casing due to the weight. It cannot fall through the rotating separator, for example, it falls downward. The raw material that cannot pass through the rotary separator and falls on the rotary table is again caught in the pulverizing roller and pulverized. In addition, the raw material with a small diameter passes through between the blades, passes through the rotary separator, and is taken out from the upper outlet.

  Among the raw materials that have reached the annular passage, the raw material having a particularly large particle diameter falls below the rotary table from the annular passage and is taken out of the vertical crusher from the lower outlet, and then a carrier such as a packet elevator is used. Then, it is charged again from the raw material inlet of the vertical grinder and pulverized.

  In addition, it is abnormal vibration of a vertical grinder that is likely to be a problem in the vertical grinder described above. In the above-mentioned Patent Document 1, a temporal change in the raw material layer thickness is monitored during operation of the vertical crusher, and the raw material layer on the turntable is monotonously reduced when the raw material layer thickness monotonously decreases in a preset time width. In order to improve the thickness and avoid vibrations, a control method for a vertical crusher that adjusts the rotation speed of the rotary table to prevent abnormal vibrations is disclosed.

  By the way, regardless of whether the pulverizer is of the pressure type (method of blowing gas into the pulverizer with a fan) or negative pressure type (method of sucking the gas in the pulverizer with a fan), the vertical pulverizer is usually It is preferable to stop the operation after all the materials are dispensed on the rotary table. In practice, however, even if some of the raw material remains on the rotary table, in most cases, the operation is stopped by stopping the electric motor after a certain time has elapsed.

  For example, when an attempt is made to stop a vertical grinder, a stop command for a raw material supply device that inputs raw materials to the vertical grinder is first issued, and then a stop command for the vertical grinder is transmitted after a certain time has elapsed. Is done.

  However, in the conventional technology for predicting the occurrence of abnormal vibration by monitoring the thickness of the raw material layer on the rotary table, for example, it is necessary to always monitor the thickness of the raw material layer placed on the rotary table. Since the layer thickness may vary depending on conditions such as the measurement position, attention was required.

  In particular, there is a time lag between when the amount of new raw material supplied to the vertical crusher changes and when the thickness of the raw material layer on the rotary table actually changes. In the case where the amount of water changes drastically during operation, there is a possibility of delaying control.

  For example, in a vertical crusher that crushes coal for boilers, the input amount (supply amount) of new raw materials to be supplied to the vertical crusher is adjusted according to the boiler load. In the nighttime, the load changes every hour, and at night, the load is often reduced to 1/3 to 1/2 of the daytime. As described above, when the supply amount of the new raw material changes drastically, the conventional control method tries to suppress the vibration corresponding to the load, but there is a case where the control is delayed and the abnormal vibration cannot be effectively suppressed. there were.

  Further, in the case of the conventional stopping method described above, the rotation of the rotary table of the vertical grinder stops after a certain period of time. The air volume caused by the rotation of the rotary separator and the rotational speed of the rotary separator continue to move under certain conditions. Therefore, the rotary table continues to move at the rated speed until the vertical crusher stops after a certain time has elapsed, during which the rotary table in the vertical grinder rotates at the rated speed. In spite of this, the raw material put on the rotary table is blocked, and the thickness of the raw material layer on the rotary table is extremely thin.

  Therefore, the phenomenon that the crushing roller hits the table surface of the rotary table occurs from when the raw material supply device stop command is transmitted until the vertical crusher stops, and noise is generated. Although this noise is different depending on whether the grinding roller is provided with a mechanical stopper or not, there are many cases where this noise becomes a large noise and becomes a problem.

  In addition, when the inside of the vertical crusher is inspected, even if the supply of new raw materials is stopped when the vertical crusher is stopped, a large amount of the circulating material remains in the vertical crusher. It is accumulating. Since this deposited material is a fine powder, it may spontaneously ignite, and there is a risk of ignition and explosion at the time of restart, so when stopping, a considerable amount of water is sprinkled into the vertical crusher, etc. Measures were taken.

  However, during operation, the vertical pulverizer is often heated, and cold water is injected into the heated vertical pulverizer, causing the material of the vertical pulverizer to crack due to thermal shock. There was also a problem that occurred. Therefore, when the vertical crusher is stopped, how to suppress the generation of noise and mill vibration and how to leave no fine powder in the vertical crusher has become a major issue.

  The present invention has been made in view of the above-described requirements, and suppresses noise that is likely to occur during the operation of stopping the vertical crusher to prevent abnormal vibration, resulting from the raw material remaining in the vertical crusher. It is an object of the present invention to provide a vertical crusher control method suitable for reducing the risk of stopping in a safe state.

In order to achieve the above object, the vertical crusher control method according to the present invention comprises:
(1) A gas provided with a plurality of rotating crushing rollers and supplied onto the rotary table is pulverized between the rotary table and the crushing roller, and the crushed raw material is provided under the rotary table. A method for controlling a vertical crusher that blows up with a gas introduced from an introduction port and takes out the gas together with the gas from a product outlet provided above the rotary table, and reduces the amount of raw material supplied to the vertical crusher In this case, the number of revolutions of the rotary table is reduced before actually changing the supply amount of the raw material.

  (2) The raw material supplied on the rotary table having a plurality of rotating crushing rollers is pulverized between the rotary table and the crushing roller, and the pulverized raw material is provided below the rotary table. A method for controlling a vertical crusher that blows up with a gas introduced from an introduction port and takes out the gas together with the gas from a product outlet provided above the rotary table, and reduces the amount of raw material supplied to the vertical crusher In this case, the rated rotational speed of the electric motor that drives the rotary table is reduced by inverter control to reduce the rotational speed of the rotary table.

  (3) In the vertical pulverizer control method according to (1) or (2), when a supply amount change signal for changing the supply amount of the raw material is received when the vertical pulverizer is stopped. Prior to actually changing the supply amount of the raw material, the rotational speed of the rotary table is reduced.

  (4) In the method for controlling a vertical crusher according to any one of (1) to (3), when the rotational speed of the rotary table is reduced, the air volume of a fan for taking out the pulverized raw material to the outside Reduce.

  (5) The vertical crusher control method according to the present invention includes a plurality of rotatable crushing rollers, and crushes the raw material supplied on the rotating table between the rotating table and the crushing roller. In the vertical pulverizer control method, the amount of new raw material supplied to the vertical pulverizer is detected, and the rotational speed of the rotary table is adjusted according to the amount of the new raw material.

  (6) In the method for controlling a vertical crusher according to (5), the relationship between the amount of new raw material supplied to the vertical crusher and the rotational speed of the rotary table is stored in advance, and the stored relationship Based on the above, the number of rotations of the rotary table is adjusted according to the detected amount of the new raw material.

The vertical crusher control device according to the present invention includes:
(7) A control device for a vertical crusher that performs the control method according to (6), the measuring device for detecting the amount of new raw material supplied to the vertical grinder, and the amount of the new raw material, A storage device for storing the relationship with the table rotational speed, and in accordance with the amount of the new raw material detected by the measuring device based on the relationship between the amount of the new raw material stored in the storage device and the table rotational speed. Adjust the rotation speed of the rotary table.

According to the present invention, when the vertical crusher is stopped, the thickness of the raw material layer on the rotary table is reduced by reducing the rotational speed of the rotary table prior to changing the supply amount of the raw material by the raw material supply device. Can be maintained in a constant state, so that occurrence of a phenomenon that the crushing roller hits the table surface of the rotary table can be suppressed, and noise can be reduced.
In addition, according to the present invention, abnormal vibration of the vertical crusher can be predicted from the amount of new raw material supplied into the vertical crusher, so the rotational speed of the rotary table of the vertical crusher is reduced before abnormal vibration occurs. Thus, abnormal vibration can be suppressed.

It is explanatory drawing for demonstrating the schematic structure of the vertical crusher which implement | achieves the control method of the vertical crusher which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating notionally the grinding | pulverization system using the same saddle-type grinder. It is a graph showing the relationship between the pulverization amount and the air volume in the same type pulverizer. It is a graph showing the relationship between the table rotation speed of the rotary table and the mill load in the same crusher. It is a graph showing the relationship between the speed of a granular material and a dynamic friction coefficient in the same saddle-type grinder. It is a graph showing the relationship between a frequency ratio and a vibration amplification coefficient. It is explanatory drawing for demonstrating the schematic structure of the vertical crusher which implement | achieves the control method of the vertical crusher which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vertical crusher 2 Rotary table 3 Crushing roller 13 Raw material input chute 14 Rotating separator 15 Dam ring 1B Casing 20 Raw material hopper (for new raw material supply)
21 Raw material hopper 25 Bucket elevator 30 Annular passage 33 Gas inlet 34 Lower inlet 35 Raw material inlet 39 Upper outlet 50 Control panel 50A Controller 50B Timer device 50C Memory 89 Exhaust fan (blower)

  Hereinafter, preferred embodiments of a control method for a vertical crusher according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an explanatory diagram for explaining a schematic structure of a vertical pulverizer that realizes the vertical pulverizer control method according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram for conceptually explaining a pulverization system using the same type pulverizer. FIG. 3 is a graph showing the relationship between the pulverization amount and the air volume in the same type pulverizer. FIG. 4 is a graph showing the relationship between the table rotation speed of the rotary table and the mill load in the same crusher. FIG. 5 is a graph showing the relationship between the speed of the granular material and the dynamic friction coefficient in the same type crusher. FIG. 6 is a graph showing the relationship between the frequency ratio and the vibration amplification coefficient.

First, a preferable configuration of the vertical crusher 1 that realizes the control method according to the first embodiment will be described.
As shown in FIG. 1, the vertical crusher 1 includes, for example, a casing 1B that constitutes the entire outer shell, a rotary table 2 that rotates horizontally in the casing 1B, and an upper surface 2A ( And a plurality of conical crushing rollers 3 disposed at positions that equally divide the outer peripheral portion of the rotating table upper surface 2A in the circumferential direction.

  The vertical crusher 1 includes, for example, a speed reducer 2B installed below the rotating roller 2, a variable speed motor 2M that drives the rotary table 2 via the speed reducer 2B, and the motor 2M. And a control panel 50 for controlling the number of rotations. The control device 50A provided in the control panel 50 includes a CPU, a ROM, a RAM, and the like, and controls the rotation speed of the electric motor 2M based on information from the boiler master and the vibration sensor S2 provided in the casing 1B.

  When the control device 50A receives a supply amount change signal for changing the supply amount of the raw material from the boiler master to the vertical crusher 1, the timer device 50B counts whether a predetermined time has elapsed. To do. The time measured by the timer device 50B can be arbitrarily set.

  The crushing roller 3 is connected to the piston rod 9 of the hydraulic cylinder 8 through an upper arm 6 pivotally attached to the lower casing by a shaft 7 and a lower arm 6A formed integrally with the upper arm 6. ing. The crushing roller 3 is pressed in the direction of the upper surface 2A of the turntable 2 by operating the hydraulic cylinder 8, and rotates by being driven by the raw material through the turntable upper surface 2A.

  A rotary separator 14 is provided at the upper center of the rotary table upper surface 2A of the casing 1B, and a raw material charging chute 13 is disposed so as to penetrate the central axis of the rotary separator 14 vertically. The vertical crusher 1 of this example is configured so that a raw material can be charged or supplied from the raw material charging port 35 of the raw material charging chute 13 to the upper surface 2A of the rotary table via the raw material charging chute 13.

  The rotary separator 14 includes, for example, a plurality of blades 14A arranged in a reverse truncated cone shape having a diameter increased upward with the rotation axis of the rotary separator 14 as a center, with a gap of a predetermined interval between them. It is rotationally driven by a driving device (not shown). An annular passage 30 is provided in the gap between the outer peripheral portion of the turntable upper surface 2A and the casing 1B.

  In the first embodiment, the electric motor 2M is configured by a method capable of variable speed by an inverter power source (not shown), for example, and the electric motor 2M can drive the rotary table 2 via the speed reducer 2B. It is connected with. Therefore, the electric motor 2M can freely change the rotation speed and the rotation speed of the turntable 2 by freely changing the rotation speed according to the control signal transmitted from the control device 50A of the control panel 50.

  Next, a preferred example of a grinding system using the vertical grinder 1 configured as described above will be described with reference to FIG. As illustrated in FIG. 2, the pulverization system 10 includes, for example, a vertical pulverizer 1, raw material hoppers 20 and 21, a bucket elevator 25, and an exhaust fan 89. The raw material stored in the raw material hopper 20 is put into the vertical crusher 1 through the bucket elevator 25 and the raw material hopper 21 and pulverized.

  The raw material pulverized in the vertical pulverizer 1 is moved upward in the vertical pulverizer 1 by the gas flow of the exhaust fan 89 and taken out from the upper outlet 39. Further, among the raw materials charged into the vertical crusher 1, some raw materials that have not been taken out of the machine from the upper take-out port 39 are taken out from the lower take-out port 34 to the bucket. It is again put into the vertical crusher 1 through the elevator 25 and the raw material hopper 21 and pulverized.

  Hereinafter, the operation and control method of the vertical crusher 1 will be described. In the vertical crusher 1 used in the first embodiment described above, for example, the number of crushing rollers 3 is 3, the number of rotations of the rotary table 2 is 73 rpm, and the center diameter of the crushing rollers 3 is. D is 0.4 m, and the diameter T of the turntable 2 is 0.64 m.

  First, the raw material supplied chute 13 feeds the raw material supplied to the central portion of the rotary table 2 toward the outer peripheral portion of the rotary table 2, and is caught between the rotary table 2 and the grinding roller 3 and pulverized. The A part of the raw material that is pulverized by being sandwiched between the rotary table 2 and the pulverizing roller 3 thus passes over the dam ring 15 provided around the outer edge of the rotary table 2, and the outer periphery of the upper surface 2A of the rotary table. It heads for the annular channel | path 30 which is a clearance gap between a part and the casing 1B.

  During operation of the vertical pulverizer 1, gas is introduced into the apparatus by an exhaust fan 89 from a gas inlet 33 provided at the lower portion of the vertical pulverizer 1, and vertical pulverization is performed via the rotary separator 14. It is discharged out of the machine from an upper outlet 39 provided above the machine 1. As a result, in the casing 1 </ b> B of the vertical crusher 1, a gas airflow is generated from below the rotary table 2 to above the rotary separator 14. Therefore, a part of the raw material that has passed over the dam ring 15 and reached the annular passage 30 is blown up by the gas flow and rises in the casing 1B.

  The airflow rising in the casing 1B is influenced by the rotary separator 14 and is an airflow rising while turning. Therefore, among the raw materials blown up by the air current, the raw material having a large diameter and a large weight falls below the casing 1B due to the weight, or from the air current due to centrifugal force generated in the raw material itself by swirling by the air current. It deviates and falls below the casing 1B and cannot pass through the rotary separator 14.

  The raw material that cannot pass through the rotary separator 14 circulates in the vertical pulverizer 1 as described above, and is re-engaged in the pulverizing roller 3 and pulverized. Alternatively, the dropped raw material falls below the rotary table 2 through the annular passage 30 and is taken out of the vertical crusher 1 from the lower take-out port 34, and then via a conveyor such as the bucket elevator 25, It is charged again from the raw material charging port 35 of the vertical crusher 1 and pulverized. The raw material having a small diameter passes between the blades 14 </ b> A, passes through the rotary separator 14, and is taken out from the upper outlet 39.

Next, a control method when stopping the vertical crusher 1 will be described.
First, in the first embodiment of the vertical pulverizer 1 according to the present invention, when the amount of raw material supplied to the vertical pulverizer 1 is decreased, the supply amount of the new raw material by the raw material hopper 20 is actually changed. Prior to this, control is performed so as to reduce the rotational speed of the rotary table 2. Specifically, for example, when the vertical pulverizer 1 is stopped, the vertical pulverizer 1 from a boiler master (boiler control device) (not shown) in a plant such as a combustion facility provided with the vertical pulverizer 1 is used. When a supply amount change signal for changing (for example, reducing the supply amount) the supply amount of the new raw material to be supplied by the material hopper 20 is received, the following control is performed.

  That is, before actually changing the supply amount of the raw material, for example, wait until a predetermined time elapses from the time when the supply amount change signal is received until the start of the supply amount change by the raw material hopper 20, and during that time, the inverter power supply not shown is controlled Thus, the rotational speed of the electric motor 2M that drives the rotary table 2 is reduced from the rated rotational speed. Then, even if the circulating raw material remaining in the vertical crusher 1 is purged by the suction force of the exhaust fan 89 by changing the supply amount of the raw material after a predetermined time has passed, Since the remaining raw material layer thickness can be maintained at a predetermined height, it is possible to effectively prevent noise caused by vibration when the vertical crusher 1 stops, and to cause problems such as ignition of fine powder. Can be suppressed.

  As the rotational speed of the turntable 2 is controlled in this way, if the suction amount (air volume) of the exhaust fan 89 is reduced together, the particle size of the raw material discharged out of the vertical crusher 1 is reduced. It is more preferable because it does not change greatly as compared with normal operation. FIG. 3 shows the relationship between the pulverization amount of the vertical pulverizer 1 and the air volume. Usually, the work amount of the vertical pulverizer 1 is proportional to the rotational speed of the rotary table 2, and the vertical pulverizer 1 The amount of air passing through the vertical crusher 1 when the load is turned down to about 1/3 to 1/2 of the rated load (load reduction) is set as shown in FIG.

  As shown in FIG. 4, for example, when a turndown signal (a supply amount change signal or the like) is output from the boiler master, the control device 50 </ b> A of the control panel 50 actually changes the supply amount of the raw material such as the raw material hopper 20. Prior to (ie, before changing), the number of rotations of the rotary table 2 of the vertical crusher 1 is reduced to reduce the load as shown. Thereafter, the supply amount of the raw material is actually changed after a predetermined time has elapsed. For example, in the graph shown in FIG. 3, if the pulverization amount is maintained at about 70% at the time of turndown, the lower limit speed in the piping portion of the conveyance air (including fine powder) conveyed to the burner portion (combustion portion) of the plant (not shown). Can be secured.

  In this way, the thickness of the raw material layer on the rotary table 2 is made extremely thin by actually changing the supply amount of the raw material after reducing the rotational speed of the rotary table 2 and reducing the air volume, the pulverization amount, and the like. Therefore, it is possible to prevent the noise by suppressing the vibration of the entire vertical crusher 1 due to the impact vibration of the crushing roller 3 or the like.

  This can be explained from the relationship between the rotation speed of the turntable 2 and the dynamic friction coefficient. FIG. 5 shows the relationship between the rotational speed of the turntable 2 and the dynamic friction coefficient (dynamic friction coefficient between the grinding roller 3 and the raw material). According to the present embodiment, since the rotational speed of the turntable 2 is reduced before a predetermined time elapses before the supply amount of the raw material is changed, the thickness of the raw material layer on the turntable 2 is set to a predetermined height. Can keep. As a result, the friction coefficient between the pulverizing roller 3 and the raw material increases, and as a result, slippage hardly occurs in the pulverizing portion.

  For this reason, when the vertical crusher 1 is stopped, the rotational speed of the turntable 2 is changed prior to changing the supply amount of the new raw material fed from the raw material hopper 20 or the like into the vertical crusher 1. Should be reduced from the rated speed. In accordance with this, even if the rotational speed of the rotary separator 14 is reduced or the circulating raw material remaining in the vertical crusher 1 is purged by the suction force of the exhaust fan 89, the first implementation is performed. According to the vertical crusher 1 according to the embodiment, the thickness of the raw material layer on the rotary table 2 can be maintained at a constant height, and as described above, the risk of noise prevention and explosion can be avoided. It is effective for.

  In the first embodiment, the inverter power source (inverter control) is used to reduce the rotational speed of the rotary table 2 from the rated rotational speed. However, the rotational speed of the rotary table 2 is reduced from the rated rotational speed. The method of making is not limited to this, and various methods can be adopted.

  By the way, the relationship between the friction coefficient and the vibration of the vertical crusher 1 tends to be the starting point of vibration and noise when the friction coefficient is lowered, and can be said to be the starting point of self-excited vibration. Conventionally, the vertical crusher is operated in a state where the air volume is constant as described above. In addition to the friction coefficient, the vibration that is the source of noise generated in the vertical crusher 1 can also be considered as follows.

  Displacement due to vibration (A) = (Excitation force / Spring constant) x M (Vibration amplification factor)

A displacement amount (A) is obtained by dividing the excitation force by the spring constant.
Moreover, as shown in FIG. 6, it turns out that it changes with the proportionality of the vibration amplification coefficient M, the vibration frequency ((omega)), and the frequency ((omega) 0) of a grinding | pulverization layer (raw material layer). Usually, in FIG. 6, since ω / ω0 is operated at 1.0 or less (= resonance point or less), the frequency (ω0) of the pulverized layer is not changed (proportional to the particle size of the product, By reducing the excitation frequency (ω), the vibration amplification coefficient M can be reduced.

  Since the vibration frequency (ω) is proportional to the rotation speed of the grinding roller 3, the vibration frequency (ω) can be reduced by changing the rotation speed of the rotating table 2 to be synchronized. As a result, if the inner molecule of the denominator numerator ω / ω0 is lowered, the vibration amplification coefficient M decreases, so that the vibration of the vertical crusher 1 can be suppressed.

  As described above, methods for suppressing or suppressing vibration and noise include a friction coefficient securing method and an excitation frequency control method. What is common to these two methods is the rotational speed of the rotary table 2, and by setting the appropriate rotational speed each time according to the raw material properties, the capacity of the vertical crusher 1 can be maximized. it can.

  That is, when the supply amount of the raw material to the vertical crusher 1 is decreased, the rotational speed of the turntable 2 is decreased prior to actually changing the supply amount of the raw material. Specifically, when the vertical crusher 1 is stopped, prior to changing the supply amount of the raw material, the rotational frequency of the rotary table 2 is decreased to decrease the vibration frequency (ω), thereby amplifying the vibration. If the coefficient M is reduced, vibration and noise factors can be eliminated while the raw material layer thickness on the turntable 2 is maintained at a constant height.

  Next, a control method and control device for a vertical crusher according to a second embodiment of the present invention will be described. FIG. 7 is an explanatory diagram for explaining a schematic structure of a vertical pulverizer that realizes the vertical pulverizer control method according to the second embodiment of the present invention. In the following description, the same reference numerals are assigned to portions that overlap with the portions that have already been described, and description thereof is omitted, and portions other than those particularly related to the present invention may not be specified.

  As shown in FIG. 7, the type of vertical pulverizer 1 that can be used in the second embodiment is not limited to that described above. For example, the vertical pulverizer is a tire type vertical pulverizer in which the shape of the pulverizing roller 3 is a spherical shape. 1 may be sufficient. Further, the rotary separator 14 may be a fixed type according to the required particle size of the product (powder particles).

  Here, in 2nd Embodiment, the grinding | pulverization system 10 (refer FIG. 2) measures the quantity of the new raw material supplied to the vertical crusher 1 from the hopper 20 shown in FIG. 2 in 1st Embodiment. A flow rate sensor S1 and a vibration sensor S2 for measuring a vibration value of the vertical crusher 1 are provided as a measuring instrument for performing the measurement. The flow sensor S1 in the second embodiment measures the weight of the raw material discharged from the hopper 20 per unit time.

  The control panel 50 of the vertical crusher 1 according to the second embodiment is detected by the vibration sensor S2 by changing the supply amount of a new raw material in advance during operation of the vertical crusher 1 together with the control device 50A. A storage device 50C is provided that detects and records the supply amount of a new raw material immediately before the vibration value exceeds the allowable range of the vertical crusher 1 as a boundary value by the flow rate sensor S1.

  4 used in the first embodiment shows the relationship between the table rotation speed of the turntable 2 and the mill load (amount of new raw material supplied to the vertical crusher 1). This is a graph of changes in boundary values that differ for each rotation speed. In FIG. 4, for example, the rated rotation speed of the turntable 2 is set to 100, and the minimum amount of new raw material that can be supplied without causing abnormal vibration at this time is set to 100, which is the reference value.

  And as shown in FIG. 4, it turns out that it is necessary to slow down a table rotation speed, so that the quantity of the new raw material grind | pulverized with the vertical grinder 1 is small. In other words, when the amount of new raw material supplied to the vertical crusher 1 is decreased from 100, the amount of new raw material that can be supplied without causing abnormal vibration is reduced. In order to suppress the occurrence of abnormal vibration when reduced to 30% of the reference value), the table rotation speed of the rotary table 2 must be reduced to 50 (50% of the rated rotation speed which is the reference value). I understand that.

  The above relationship depends on the type of the vertical crusher 1 or the type of raw material to be crushed, but can be reproduced if it is the same raw material and the same type. However, when the air volume of the gas introduced into the vertical pulverizer 1 changes, the amount of raw material circulating in the vertical pulverizer 1 changes, and the pulverization amount changes as shown in FIG. It is preferable to take this into consideration, and when controlling in the second embodiment, it is preferable to keep the gas flow rate constant. Further, when the gas air volume changes greatly, it is preferable to correct the relationship between the amount of the new raw material and the table rotation speed of the turntable 2 in consideration of the effect of the air volume.

  In the second embodiment, the table rotation speed of the turntable 2 that is appropriate for the amount of the new material measured by the flow sensor S1, and the relationship between the amount of the new material stored in the storage device 50C and the table rotation speed. And a control device 50A for transmitting a control signal for increasing or decreasing the rotational speed of the electric motor 2M.

  Next, the control method of the vertical crusher 1 of 2nd Embodiment is demonstrated. First, the vertical crusher 1 according to the second embodiment of the present invention operates while detecting the amount of a new raw material supplied from the hopper 20 in advance with the flow sensor S1 as described above. The generated vibration value is measured by the vibration sensor S2.

  Then, the supply amount of the new raw material immediately before the vibration value exceeds the allowable range of the vertical crusher 1 is detected as a boundary value, and the change in the boundary value that differs for each table rotation speed of the rotary table 2 is determined as the amount of the new raw material. It is stored in the storage device 50C as the relationship with the table rotation speed.

  Thus, the vertical crusher 1 which concerns on 2nd Embodiment has memorize | stored the change of the boundary value which changes for every table rotation speed of the turntable 2 as the relationship between the quantity of a new raw material, and a table rotation speed. . Then, the rotational speed of the electric motor 2M is controlled so that the amount of the new raw material supplied from the hopper 20 and the rotational speed of the rotary table 2 are in this relationship. The relationship between the amount of the new raw material and the table rotation speed is actually measured before the control operation, and is input to the control panel 50 as a set value in advance and stored in the storage device 50C before the control operation. It may be.

  In other words, during the control operation of the vertical crusher 1, the amount of the raw material is detected by the flow rate sensor S1, and an appropriate table rotational speed of the rotary table 2 is calculated from the amount of the raw material detected by the flow rate sensor S1. The control device 50A transmits a control signal for adjusting the rotational speed to the electric motor 2M and adjusts the rotational speed of the rotary table 2 by increasing or decreasing it, thereby preventing abnormal vibration.

  In the second embodiment, the weight of the new raw material actually supplied from the hopper 20 is measured and detected by the flow sensor S1, but the scope of application of the present invention is not limited to this, and is transmitted to the hopper 20, for example. The weight of the new raw material may be detected from the supply amount command signal or the supply amount setting value.

  FIG. 5 shows the relationship between the rotation speed of the turntable 2 and the dynamic friction coefficient (dynamic friction coefficient between the crushing roller 3 and the raw material) as described above. It can be seen that slipping and the like are less likely to occur, so that there is an effect of suppressing the vibration of the vertical crusher 1. For these reasons, during operation of the vertical crusher 1, it is considered effective to prevent vibrations by adjusting the rotational speed of the rotary table 2 and restoring the dynamic friction coefficient between the crushing roller 3 and the raw material. .

  That is, when the differential pressure of the vertical crusher 1 deviates from a predetermined value and increases, the vertical rotation is reduced if the table rotation number is arbitrarily reduced, the excitation frequency is decreased, and the vibration amplification coefficient is decreased. It is possible to eliminate the vibration factor before the vibration of the machine 1 is generated.

Claims (2)

The raw material supplied to the rotary table with a plurality of rotating pulverizing rollers is pulverized between the rotary table and the pulverizing roller, and the pulverized raw material is supplied from a gas inlet provided below the rotary table. A control method for a vertical crusher that is blown up by introduced gas and is taken out together with the gas from a product outlet provided above the rotary table,
When actually reducing the amount of raw material supplied to the vertical crusher, prior to actually changing the amount of raw material supplied, the rotational speed of the rotary table is reduced,
A method for controlling a vertical crusher, characterized in that when the rotational speed of the rotary table is reduced, the air volume of a fan for taking out the pulverized raw material to the outside is reduced. When a supply amount change signal for changing the supply amount of the raw material is received when stopping the vertical crusher, the rotational speed of the rotary table is set before actually changing the supply amount of the raw material. The method for controlling a vertical crusher according to claim 1, wherein the control is performed.

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