JPH0584447A - Vertical grinder - Google Patents

Abstract

PURPOSE:To provide a vertical grinder capable of quietening abnormal vibration and of returning to an original stable operation state by automatically changing both the tension hydraulic pressure of a grinding roll and the rpm of a turntable before vibration value is suddenly increased by some cause during operation and also this state is continued and thereby operation is made impossible. CONSTITUTION:A vibrometer 140 is fitted to a casing 15 and also a variable speed motor 2A is used for a motor for driving a turntable. A controlling device 150 is equipped which lowers the tension hydraulic pressure of a hydraulic unit 9A or lowers the rpm of the variable speed motor 2A when a vibration mode recorded by the vibrometer 140 is compared with the previously set vibration mode and both coincide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical crusher for crushing raw materials such as limestone, slag, clinker, cement raw materials and chemicals in cooperation with a rotary table and a pulverizing roller.

[0002]

2. Description of the Related Art FIG. 4 is a kind of crusher for pulverizing raw materials such as limestone, slag, and cement raw materials into fine powder.
As shown in (1), a vertical crusher 1 having a rotary table and a crushing roller is widely used. This kind of crusher
At the lower part of the cylindrical casing 15, a disk-shaped rotary table 3A is driven by the speed reducer 2K by the constant speed motor 2K and rotates at a low speed, and 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 a plurality of crushing rollers 4 which are driven to rotate.

The crushing roller 4 has a casing 15 and a rotating shaft 6
Is connected to a piston rod 10 of a hydraulic cylinder 9 via an arm 5 and an arm 7 which are swingably supported by, and by operating the hydraulic cylinder 9, the crushing roller 4 is pressed onto the rotary table 3A. To give crushing pressure to the raw materials. 3B is a dam ring provided on the outer peripheral edge of the rotary table 3A for adjusting the raw material layer thickness, 14 is a gas blowing annular space passage around the rotary table 3A, 14A is a gas supply passage, and 13 is a raw material crushed by blades 13A. A rotary separator for classification, 16 is an outlet for taking out a product together with gas, and 17 is a raw material charging chute.

In such a vertical crusher, the raw material supplied to the central portion of the rotary table by the raw material feeding chute 17 receives the centrifugal force in the radial direction of the rotary table 3A and slides on the rotary table 3A. At times, the rotary table 3A receives a force in the rotation direction, and the rotary table 3A
It slides with A and performs a rotation somewhat slower than the rotation speed of the rotary table 3A. The above two forces, that is, the radial direction force and the rotational direction force are combined, and the raw material is the rotary table 3.
A spiral locus is drawn on A to move to the outer peripheral portion of the rotary table 3A. Since the roller is pressed against the outer periphery and is rotating, the raw material in which the spiral is drawn enters the crushing roller 4 and the rotary table 3A from a direction forming an angle with the roller axial direction and is bitten. It is crushed and crushed.

On the other hand, at the base of the casing 15, gas such as air or hot air is introduced by a duct,
This gas blows up from the annular space portion 14 between the outer peripheral surface of the rotary table 3A and the inner peripheral surface of the casing, so that the pulverized fine powder is entrained in the gas and the casing 1
5, the blade 1 of the separator 13 that is located in the upper part
The product having a predetermined particle size is subjected to the classification action by 3A and is discharged together with the gas from the discharge port 16 and sent to the next step.

[0006]

In the conventional vertical crusher as described above, in order for the raw material dropped on the rotary table 3A of the pulverizer to be successfully brought into contact with the pulverizing roller 4 and to be bitten, the raw material is In the case of a raw material having a smooth surface with a smooth surface and a small friction coefficient, even if the crushing roller 4 is strongly pressed toward the rotary table 3A, the raw material interposed between the two is It is not possible to escape to the side and give effective crushing power to the raw material. Raw materials with a small coefficient of friction generally contain less water, so
The coefficient of friction must be increased by adjusting the water content of the raw material to an appropriate value in advance. Of these raw materials with low water content and low friction coefficient, especially those with relatively poor pulverizability,
Mill vibration often occurs, and when the vibration value (amplitude) is particularly large, the equipment may be damaged or operation may stop, and the machine may be forced to suspend operation.

As described above, when the vibration value of the mill during operation becomes much larger than the normal value of 50 μm of one-sided amplitude, and when this state continues, some measure is taken to reduce the vibration value of the mill immediately. There must be. As a means for that, for example, the raw material supplied to the crusher is temporarily reduced, the air flow of the mill is increased, water is added to the raw material, or the mill operation is stopped. .. However, a decrease in the supply of raw materials and suspension of mill operation lead to a decrease in processing capacity. An increase in air flow through the mill results in coarser product grain size, resulting in lower product quality. Improving the friction coefficient by adding moisture increases product moisture. Then, the quality of the product is deteriorated, which in turn has a secondary adverse effect.

The vibrations of the vertical crusher are roughly classified into transient vibrations and self-excited vibrations. The transient vibrations are shown in FIG.
As shown in, the amplitude is small and the amplitude is small and converges in a short time.
On the other hand, the self-excited vibration is also called "chatter vibration", and as shown in Fig. 6, once the vibration starts, it lasts for a considerable time and the amplitude is large, resulting in damage to the equipment and reduction in pulverization efficiency. ， In extreme cases, it becomes impossible to operate.

[0009]

In order to solve the above problems, in the vertical crusher of the present invention, a plurality of rotatable crushing rollers are arranged on the upper surface of the outer peripheral portion of the rotary table. A vertical pulverizer provided with a hydraulic means for varying the oil pressure for pressing the crushing roller against the rotary table and crushing the raw material supplied to the central part of the rotary table between the upper surface of the rotary table and the peripheral surface of the crushing roller, in the casing. With the vibrometer attached, the electric motor for driving the rotary table is a variable speed electric motor, and when the vibration mode measured by the vibrometer matches a preset vibration mode, the hydraulic pressure of the hydraulic means is lowered, Alternatively, a control device for reducing the rotation speed of the variable speed motor is provided.

[0010]

In the vertical crusher of the present invention, the vibration mode measured momentarily by the vibrometer attached to the casing of the vertical crusher is compared with the preset vibration mode, and only when the set vibration mode is met. , The hydraulic pressure of the hydraulic means (hydraulic cylinder), which is a means for pressing the crushing roller against the rotary table, is reduced to suppress abnormal vibration. If the hydraulic pressure has already dropped at this time, the vibration value is reduced by lowering the rotational speed of the variable speed electric motor for driving the rotary table. The designated vibration mode that requires measures against vibration is so-called self-excited vibration (also called "chatter vibration"), and other than that, action is taken for transient vibration that has small amplitude and disappears instantaneously. Even if you don't take it, there is no problem because it will calm down soon. As a result of implementing the above countermeasures against abnormal vibration, after returning to a stable state, the operating conditions will return to normal even if the hydraulic pressure and the number of revolutions are gradually increased.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 3 show a vertical crusher according to an embodiment of the present invention, FIG. 1 is a flow sheet of the vertical crusher, FIG. 2 is a control block diagram of a controller, and FIG. 3 is a control system diagram. .. In the figure, 1 is a vertical crusher, 2A is a variable speed electric motor for driving a rotary table, 2B is a controller for the variable speed electric motor 2A, 9A is a hydraulic unit of a hydraulic cylinder 9 which is a hydraulic means for tensioning the crushing roller 4, 9B is a pressure gauge, 6
0 is a raw material conveyor, 70 is a raw material hopper, 80 is a constant feed ware, 80a is a variable speed electric motor for the same, 8
0b is a constant feed ware 80 weighing machine, 9
0 is a dust collector, 100 is a suction fan, 130 is a vibrometer,
140 is a differential pressure gauge, 140a and 140b are pressure gauges, 1
Reference numeral 50 denotes a control device, and the control device 150 includes a setter, a controller (regulator and operator), as shown in FIG.
The amplifier is stored. Each device of the main body of the vertical crusher 1 is as described in the related art, and its description is omitted.

Next, the operation of the controller 150 will be described. As shown in FIG. 2, the measurement result of the vibrometer 140, which is measured at every time interval set by the timer, the rotation speed of the variable speed motor 2A, the crushing roller 4, and the tensioning hydraulic cylinder 9
The tension pressure of the pressure gauge 9B and the information of the differential pressure gauge 140 are converted into an electric signal and input to the control device 150. Of these four pieces of information (vibration value, rotation speed, tension pressure and mill differential pressure), the vibration mode (vibration waveform) is compared with the designated vibration mode input to the setting device in advance by the comparator, and the measured vibration When the mode matches the specified vibration mode,
Although the hydraulic pressure of the hydraulic cylinder 9 for tensioning the crushing roller 4 is reduced via the controller, when the hydraulic pressure is already low, the rotational speed of the variable speed electric motor 2A is controlled to reduce the rotational speed of the rotary table 3A. The setter has a specified vibration mode, standard speed,
Turn on the standard tension hydraulic pressure. The controller is composed of an adjuster and an operating device, and the adjuster adjusts the tension hydraulic pressure and the rotation speed of the variable speed electric motor 2A for driving the rotary table according to the difference between the vibration mode and the vibration value (maximum amplitude) and the set value. The range of extinction is instructed, and its control operation is proportional operation (P operation), integral operation (I operation), derivative operation (D operation), proportional integral operation (PI operation), proportional derivative operation (PD operation). ) Etc. can be used properly according to the situation of the change of the vibration value. In addition to the above, the controller also has a role of instructing the width of decreasing the rotational speed and the width of decreasing the tension hydraulic pressure according to how the measured value exceeds the set value of vibration. The operation unit transmits the operation command to the controller 2B of the variable speed electric motor 2A and the hydraulic unit 9A based on the instruction from the controller. The lines with arrows in the figure show the flow of signals.

FIG. 3 shows the flow of the control system of the present invention, in which the measured vibration waveform and vibration value are compared with the designated vibration mode,
When the tension hydraulic pressure of the hydraulic cylinder 9 is lower than the designated range when the designated mode is matched or substantially matched, the rotation speed of the variable speed electric motor 2A for driving the rotary table is decreased, and when the tension hydraulic pressure is not lower than the designated range, the hydraulic pressure is adjusted. Decrease. On the other hand, when the vibration value is low and the vibration mode is different from the specified one,
If the tension hydraulic pressure is below the specified range, the hydraulic pressure is increased, and if the tension hydraulic pressure is within the specified range, the decrease in the rotational speed is covered and increased. The control in the case of Fig. 3 performs two operations of oil pressure and rotation speed when vibration occurs, and selectively uses oil pressure change operation and rotation speed change operation according to the degree of vibration. According to the above, the person who is effective in suppressing the vibration is mainly controlled. The above-mentioned vibration mode designation modes are all self-excitatory vibration modes as shown in FIG. 6, but in addition to this, a medium vibration mode is designated.
You may implement the operation with respect to this. Compared to the method of changing only the hydraulic pressure or the change of the number of rotations of the rotary table in response to the occurrence of abnormal vibration, the above method can be applied to the type of raw material, the situation of vibration, or the fineness of the product. Since there is a wide range of choices for vibration countermeasures, and both can be weighted (specifically, how much the oil pressure should be reduced or how many revolutions should be reduced, depending on the degree of abnormal vibration). Appropriate operation is possible.

In addition, with respect to the above-mentioned two operations, a constant feed rate is adjusted so that the initially set mill differential pressure is obtained in accordance with the change in the mill internal pressure loss (mill differential pressure) due to the change in the operating condition in the mill. The rotation speed of the variable speed electric motor 80a of the wear 80 is adjusted, and as a result, the raw material supply amount changes. When the abnormal vibration as described above is subsided and returns to a stable operating state, the hydraulic pressure and the table rotation speed are returned to the original state within a possible range.

By performing the automatic control having the feedback mechanism as described above, when the vibration value sharply increases and this state is continued, the oil pressure is lowered to promptly improve this state. By lowering the rotation speed or lowering the rotation speed, the biting and crushing action of the raw material is improved, and the original stable operating state can be restored.

[0016]

As is apparent from the above description, in the vertical crusher of the present invention, the vibration value of the crushing roller is automatically increased before the vibration value becomes large during operation and the vibration value continues and eventually becomes inoperable. The hydraulic pressure and rotary table speed are changed to suppress the continuation of abnormal vibration and restore the original stable operating condition. In addition, after abnormal vibration is stopped, it automatically returns to the standard operating state to prevent a reduction in the crushing amount, ensuring long-term stable continuous operation, and improving maintenance, operability, and production efficiency.

[Brief description of 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 a control system diagram showing one embodiment of a vertical crusher of the present invention.

FIG. 4 is an overall vertical sectional view of a conventional vertical crusher.

FIG. 5 is a vibration state (transient vibration) diagram of a conventional vertical crusher.

FIG. 6 is a vibration state (self-excited vibration) diagram of a conventional vertical crusher.

[Explanation of symbols]

 1 Vertical Grinder 2 Speed Reducer 2A Variable Speed Motor 2K Constant Speed Motor 3A Rotary Table 4 Grinding Roller 5 Arm 9 Hydraulic Cylinder 9A Hydraulic Unit 9B Pressure Gauge 15 Casing 60 Raw Material Conveyor 70 Raw Material Hopper 80 Constant Feed Wear 80a Variable Speed Electric Motor 80b Weighing machine 90 Dust collector 100 Suction fan 130 Vibrometer 140 Differential pressure gauge 140a Pressure gauge 140b Pressure gauge 150 Control device

Claims (1)

[Claims] 1. A rotary table is provided with a plurality of rotatable crushing rollers on an upper surface of an outer peripheral portion thereof, and a hydraulic means having a variable oil pressure for pressing the crushing rollers against the rotary table is provided, and is supplied to a central portion of the rotary table. In a vertical crusher that crushes the raw material between the upper surface of the rotary table and the peripheral surface of the crushing roller, a vibrometer is installed in the casing, and the electric motor for driving the rotary table is a variable speed electric motor. Vertical crushing, which is provided with a control device for lowering the hydraulic pressure of the hydraulic means or for lowering the rotational speed of the variable speed electric motor when the vibration mode matches a preset vibration mode. Machine.