JP2817859B2 - Vertical crusher - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical grinding machine for grinding raw materials such as limestone, slag, clinker, cement raw material and chemicals by cooperation of a rotary table and a grinding roller.

[0002]

2. Description of the Related Art As one type of a crusher for finely pulverizing raw materials such as limestone, slag, and cement raw materials into powder, FIG.
As shown in FIG. 1, a vertical pulverizer 1 having a rotary table and a pulverizing roller is widely used. This kind of crusher is
The disk-shaped rotary table 3A, which is driven by the speed reducer 2 by the motor 2A at a lower portion of the cylindrical casing 15 and rotates at a low speed, is pressed by hydraulic pressure or the like to a portion equally dividing the outer peripheral portion of the upper surface in the circumferential direction, and is driven to rotate. And a plurality of crushing rollers 4.

The crushing roller 4 is connected to a piston rod 10 of a hydraulic cylinder 9 via an arm 5 and an arm 7 which are pivotally supported on a casing 15 by a shaft 6 so that the crushing roller 4 is actuated. The crushing roller 4 is pressed on the rotary table 3A to apply crushing pressure to the raw material. 3B is a dam ring provided on the outer periphery of the rotary table 3A to adjust the thickness of the raw material layer, 14 is an annular space passage for gas blowing around the rotary table 3A, 14A is a gas supply path, and 13 is a raw material pulverized by the blade 13A. A rotary separator for classification, 16 is an outlet for taking out the product together with the gas, and 17 is a raw material input chute.

In such a vertical pulverizer, the raw material supplied to the center of the rotary table by the raw material charging chute 17 receives the centrifugal force in the table radial direction by the rotation of the rotary table 3A and slides on the rotary table 3A. When a force in the rotating direction is received by the rotating table 3A,
A slides with A and makes a rotation somewhat slower than the rotation speed of the turntable 3A. The above two forces, that is, the force in the radial direction and the force in the rotational direction are synthesized, and the raw material is
A moves to the outer periphery of the turntable 3A in a spiral locus on A. Since a roller is pressed against this outer peripheral portion and rotated, the raw material describing the spiral enters the crushing roller 4 and the rotary table 3A from a direction forming an angle with the roller axis direction and is caught. Rarely crushed.

On the other hand, a gas such as air or hot air is guided to the base of the casing 15 by a duct.
This gas blows up from the annular space 14 between the outer peripheral surface of the turntable 3A and the inner peripheral surface of the casing,
The pulverized fine powder rises inside the casing 15 together with the gas, and the blades 13A of the separator 13 located at the upper part thereof
, The product having a predetermined particle size is discharged from the outlet 16 together with the gas and sent to the next step.

In the conventional vertical crusher as described above, a considerable amount of the material to be crushed reaching the biting side of the crushing roller on the table is not caught by the crushing roller but enters the annular space. It is normal to be washed away. Of the objects to be crushed, which have been flushed into the annular space at the biting side of the crushing roller, those having a large particle diameter become stones, fall down the annular space, increase the amount of stones removed, and reduce the amount of processing work. Increase. In addition, among the crushed materials that have been washed away into the annular space, those with a small particle size will be scattered again,
The load applied to the separator increases, and the classification efficiency tends to decrease. Further, a large amount of the material to be crushed is flushed into the annular space, so that the ventilation pressure loss in the annular space increases, thereby increasing the fan power.

Therefore, the raw material is supplied to the vertical grinding machine 1 and crushed, and all the raw material which overflows the rotary table 3A and falls downward is transferred to the annular space passage 1 on the outer periphery of the rotary table 3A.
4 is sent to the separator 13 by the rising airflow blown from the rotary table 4 or the rotary table 3A against the gravity of the raw material.
To return it upward, a high-speed airflow of, for example, 20 to 50 m / sec is required, and the fan power is extremely large. For this reason, the wind speed of the ascending airflow in the annular space passage is made very small so that only the fine powder near the final product particle size is transferred to the separator 13, and most of the raw materials other than the fine powder and the crushed products of the raw materials are left as they are. A so-called external circulation system (a stone circulating system) in which the rotary table 3A is dropped from the periphery thereof, discharged to the outside of the machine, and returned to the raw material supply pipe by a transport device such as a belt conveyor or a bucket elevator. Became.

[0008]

In the external circulation system described above, the amount of pulverization (t / h) supplied into the pulverizer is the same as in the conventional method of operating a vertical pulverizer. The feed rate is controlled so that the feed rate remains constant, but the mill differential pressure fluctuates every second, and the milling section of the mill becomes overloaded, resulting in a particle size that becomes a product for the given feed rate. Without sufficient pulverization, the state in which the coarse particles and coarse powder cannot be passed through the separator and remain filled in the mill continues, which appears as a phenomenon in which the mill differential pressure increases. Therefore, in the method of adjusting the amount of the raw material supplied according to the magnitude of the differential pressure of the mill, there is a problem that the time constant is large and the control response is poor. In particular, when a material having a high powder ratio and relatively poor grindability is subjected to ultrafine pulverization, mill vibration frequently occurs, and if the vibration value (amplitude) is particularly large, the equipment may be damaged. In some cases, the operation was suspended due to damage or inability to operate.

[0009]

In order to solve the above-mentioned problems, a vertical pulverizer according to the present invention is provided with a rotary table pivotally supported so that an upper surface thereof is horizontal and driven to rotate around a vertical axis by a driving device; A rotary table provided with a raw material supply pipe for supplying raw material toward the rotary table, a crushing roller slidably disposed on the rotary table, and a rotary separator for classification disposed on the top of the rotary table; The pulverized material falling from the rising air supply section on the periphery is taken out of the pulverizer, returned to the raw material supply pipe of the pulverizer by a transport device installed outside the pulverizer, and re-input to the pulverizer. The crusher is equipped with a constant feed ware for feeding the raw material from the raw material hopper to the crusher, and a belt ware is provided on a belt conveyor for transporting the crushed material discharged out of the crusher. A particle size detector for measuring the powder ratio of the raw material in the belt conveyor is provided on the belt conveyor, and when the measured powder ratio of the particle size detector and the measured wheel feed amount of the belt wear exceed predetermined values, the constant feed is performed. -A configuration is provided with a control device that sends a command to change the rotation speed of the variable speed motor of the wear.

[0010]

In the vertical crusher of the present invention, a belt conveyor and a particle size detector are provided on a belt conveyor for transporting the raw material discharged from the crusher in the external circulation system, and the discharge amount of the discharged raw material obtained every time ( t / h) and the raw material powder ratio (the ratio of fine powder contained in the raw material) are converted into electric signals and transmitted to the control device, and the reference discharge amount set in advance by a comparator inside the control device When the set value is exceeded by comparing with the powder and powder ratio, to prevent overload in the mill, a command is sent from the control unit to the variable speed motor for constant feed wear drive according to the degree of the overload. , The output rotation speed is reduced and the supply amount is reduced. In this way, to reduce the load in the mill quickly in response to the change in grindability of the raw material and the rapid change (increase) in the raw material powder ratio, the raw material supply amount is reduced, and The present invention prevents the mill from being stopped due to equipment damage or inoperability due to sudden increase in mill vibration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a vertical pulverizer according to an embodiment of the present invention. FIG. 1 is a flow sheet, and FIG. 2 is a control block diagram of a control device. In the figure, 1 is a vertical mill, 50 is a raw material belt conveyor, 60 is a raw material hopper, 7
0 is a constant feed wear, 70a is a variable speed motor, 80 is a discharge belt conveyor, 90 is a bucket elevator, 100 is a dust collector, 110 is a suction fan, 12
0 is a particle size detector, 130 is belt wear, and 140 is a control device. The control device 140 contains therein a setting device, a controller (including a regulator and an operating device), an amplifier, and the like. Each device of the vertical mill 1 is as shown in FIG.
The description is omitted because it is the same as that described in the related art.

Next, the operation of the control device 140 will be described. As shown in FIG. From the measurement result of the raw material particle size detector 120 on the discharge belt conveyor 80, which is measured every time interval set by a timer, the raw material powder ratio (fine powder ratio in the raw material) is obtained. The discharged raw material transport amount (t / h) is measured, converted into an electric signal, and input to the comparator of the control device 140. In the control device 140 which has received this information, the reference powder ratio (percentage of fine powder in the raw material permitted in operation) and the reference discharge amount (permitted raw material amount in operation) input to the setting device in advance
The set value is compared with the measured raw material powder ratio and the raw material discharge amount. If the measured value exceeds the set value, a command is transmitted to the variable speed motor 70a via the controller in accordance with the degree of the excess to output the rotation. The number is reduced, the supply amount in the mill is reduced, the load in the mill is reduced, and the occurrence of vibration and the stoppage due to the inability to operate the mill are prevented.

The controller is composed of a controller and an operating device.
The controller reduces the output rotation speed of the constant feedware 70 in accordance with the degree to which the measured value (raw material fraction, raw material discharge amount) exceeds the set value (standard powder ratio, standard discharge amount). Are proportional operation (P operation),
The integration operation (I operation), the differentiation operation (D operation), the proportional integration operation (PI operation), the proportional differentiation operation (PD operation), and the like are used to determine the correlation between the raw material powder rate and the raw material supply amount and the load in the mill and the state of vibration generation. You can use it properly after grasping. The operation device transmits an operation command to the variable speed motor 70a based on the command from the controller. The line with the arrow in the figure indicates the signal flow.

In this way, after a certain period of time (for example, every 5 seconds) elapses by the timer after the operation is changed, the measured values obtained by the particle size detector 120 and the belt wear 130 are compared again with the set values, and the set values are compared. When it exceeds, the feed amount of the raw material is reduced again, but when the measured value falls below the set value, the raw material supply amount is increased according to the degree, and of course it is returned to the original operating state. . As a reference powder ratio, when the amount of fine powder having a particle size of 300 μ or less exceeds about 5%, it is tentatively used. However, since it slightly differs depending on the type of raw material, it is preferable to determine the reference based on past operation results. In addition, the standard emission amount is determined with reference to the operation results of the emission amount at the standard capacity according to the crusher model number.

The particle size detector 120 is an application of a measuring device of a constant feed wear (hereinafter referred to as CFW) 70. The CFW 70 includes a load detecting unit and a belt traveling distance detecting unit in one part of the conveyor, While the raw material is being sent, the load on the belt and the travel distance of the belt are converted into electric signals and transmitted to the arithmetic and control unit. In the arithmetic controller, the passage volume is calculated by integrating the passage cross-sectional area with the belt traveling distance, and the instantaneous bulk specific gravity is calculated from the accumulated weight and the accumulated passage volume. When the passage volume is maintained at a constant value, the bulk specific gravity becomes small and the bulk specific gravity becomes small when there are many bulk materials having a small amount of powder. On the other hand, when the amount of fine particles is small and the amount of fine powder is large, the porosity decreases, and the bulk specific gravity increases accordingly. Therefore, there is a correlation between the bulk specific gravity and the proportion of the fine powder contained in the raw material, that is, the raw material powder ratio. By knowing the bulk specific gravity, the value of the raw material powder ratio can be generally but known. The particle size detector 120 applies the above principle. Note that a load cell is used for a load detection unit that performs weight detection.

By performing the automatic control having the above-described feedback mechanism, the operation with a quick response can be continued. Therefore, even if the load in the mill becomes excessive and the vibration value suddenly increases and the operation becomes impossible, the operation becomes impossible. In addition, it is possible to monitor the amount of raw material discharged and the powder ratio of the raw material every moment, and to take measures to appropriately reduce the amount of raw material input.

[0017]

As is clear from the above description, in the vertical pulverizer of the present invention, the amount of raw material discharged from the pulverizer and the raw material powder ratio are maintained at appropriate values set in advance by a quick response. Operation is continued, and when the set value is exceeded, the raw material supply amount is automatically reduced to keep the raw material biting into the pulverizing roller without overload and prevent overload in the mill. In order to prevent this, stable operation with less vibration can be continued, and driving operability is improved.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a vertical crusher showing an embodiment of the present invention.

FIG. 2 is a control block diagram of the control device according to the embodiment of the present invention.

FIG. 3 is an overall vertical sectional view of a conventional vertical crusher.

[Description of Signs] 1 Vertical grinding machine 3A Rotary table 4 Grinding roller 17 Raw material feeding chute 50 Raw material conveyor 60 Raw material hopper 70 Constant feed wear 70a Variable speed motor 80 Discharge belt conveyor 90 Bucket elevator 100 Dust collector 110 Suction fan 120 Particle size detector 130 Belt wear 140 Controller

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B02C 15/00-15/04

Claims (1)

(57) [Claims] 1. A rotary table which is pivotally supported so that an upper surface thereof is horizontal and is driven to rotate around a vertical axis by a driving device, a raw material supply pipe for supplying raw material toward the rotary table, and a rotary table on the rotary table. A grinding roller slidably disposed on the rotary table and a rotary separator for classification disposed on the top, and the pulverized material falling from the rising air supply section at the periphery of the rotary table is taken out of the pulverizer and is taken out. Constant feedware that transports the raw material from the raw material hopper to the crusher in a vertical crusher that can be returned to the raw material supply pipe of the crusher by a transport device installed outside the crusher and re-input to the crusher. A belt conveyor for transporting the pulverized material discharged out of the pulverizer is provided with belt wear, and a particle size detector for measuring the powder ratio of the raw material being transported is disposed on the belt conveyor. A control device for issuing a command to change the rotation speed of the variable speed motor of the constant feed wear when the measured powder ratio of the particle size detector and the measured transport amount of the belt wear exceed predetermined values. Vertical crusher.