JP6135976B2 - How to operate the vertical crusher - Google Patents

Description

  The present invention relates to the field of fine pulverization of granular materials, and a method for operating a vertical pulverizer suitable for finely pulverizing organic raw materials including slag, clinker, limestone, coal, and other inorganic raw materials and biomass. It relates to a mold crusher.

Conventionally, a crusher called a vertical crusher (sometimes referred to as a vertical mill or a vertical roller mill) has been widely used as a crusher for crushing coal or the like.
Here, the vertical crusher has an excellent characteristic that it can efficiently finely pulverize the material to be crushed (sometimes simply referred to as a raw material in this specification), but the type of raw material. There is a problem that abnormal vibration occurs depending on the pulverization conditions. Since the abnormal vibration generated in the vertical crusher is induced by various causes, it is necessary to take various measures according to the cause of the vibration, and many countermeasures for preventing abnormal vibration have been proposed.

For example, in a vertical pulverizer, abnormal vibration may be induced when an operation of pulverizing a bulky raw material layer (in a state where the bulk density is low) at once is performed. This is because the bulky raw material layer contains a large amount of air, so that the crushing roller and the like are slippery, and apparently the friction coefficient of the raw material layer is small and slippery. Therefore, when a bulky raw material layer is pulverized all at once by the pulverizing roller, there is a high possibility that the pulverizing roller slips and slips on the raw material layer.
If the grinding roller slips on the raw material layer, the grinding roller itself rotates irregularly, and as a result, abnormal vibration occurs.

As one of the situations where the raw material layer becomes bulky, a case of finely pulverizing the raw material is known. This is because when the raw material is finely pulverized, it is necessary to repeatedly pulverize the raw material in a vertical pulverizer, and the raw material has the property of containing a larger amount of air as it becomes finer powder. The raw material that is repeatedly pulverized in the machine is called a circulating raw material, but the average particle diameter of the circulating raw material is naturally smaller than the average particle diameter of the raw material before being pulverized newly input to the vertical crusher.
If it is intended to obtain a fine product with a vertical grinder, the amount of the above-mentioned circulating raw material will inevitably increase. Therefore, if the raw material is to be finely pulverized, the amount of the circulating raw material will increase.
As a result, the raw material layer on the turntable is in a so-called bulky state in which the ratio of the raw material having a small particle diameter increases and the porosity is high. As a reference, FIG. 8 shows the relationship between the particle diameter and the dynamic friction coefficient. It can be seen that there is a difference in the apparent dynamic friction coefficient between coarse particles and fine particles.

  As one of the methods for solving the above-described problems of the prior art, the prior art as disclosed in Patent Document 1 is known. The conventional technique disclosed in Patent Document 1 is a technique in which a raw material layer on a rotary table is once compacted and uniformed using an auxiliary roller, and is then bitten by a grinding roller. If the air contained in the bulky raw material layer is degassed, vibration is reduced.

Japanese Patent Laid-Open No. 2-174946

Here, the conventional technique disclosed in Patent Document 1 can be expected to have a certain effect in terms of preventing vibration. For reference, an example of the relationship between the pressure density and the dynamic friction coefficient is shown in FIG. 9, and it can be seen that the friction coefficient tends to increase when the bulky raw material is consolidated.
In consideration of the case where the same volume of raw material is supplied to the auxiliary roller, the pressure density tends to be higher when the layer thickness is smaller. Therefore, the pressure density of the raw material in the vertical crusher can be considered as the thickness of the raw material layer.

Here, the thickness of the raw material layer below the auxiliary roller is determined by the balance between the pressure and reaction force of the auxiliary roller. Usually, immediately after the start of roller pressurization, the pressure for roller pressurization is not fully increased, and the pressure density is low in the raw material layer below the auxiliary roller.
Then, after the pressure for roller pressurization gradually increases and the pressurization is completed, the pressure density of the raw material layer below the auxiliary roller becomes high.
Therefore, by using an auxiliary roller, even in a vertical crusher that is in a state where sudden abnormal vibration is suppressed with low vibration during continuous operation, abnormal vibration may occur suddenly at startup. Therefore, the improvement was desired.
When abnormal vibration occurs, a safety device such as an interlock provided in a motor that drives the rotary table of the vertical crusher is activated to automatically stop the vertical crusher. In general, a motor for driving a rotary table or the like has an allowable start frequency from the viewpoint of motor protection, and cannot be repeatedly started and stopped continuously. Therefore, if it stops due to abnormal vibration, it may not be able to restart immediately, and production is interrupted during that time.

  The present invention has been made in view of the problems as described above, and relates to an operation method and apparatus for a vertical crusher suitable for finely pulverizing a raw material.

In order to achieve the above object, the operation method of the vertical crusher according to the present invention is as follows.
(1) A vertical crusher operating method comprising a crushing roller, an auxiliary roller, and a rotary table, wherein the raw material put on the rotary table is compressed by the auxiliary roller and degassed, and then crushed by the crushing roller. And
The auxiliary roller is made smaller than the crushing roller , and when the vertical crusher is started, the pressure start operation of the auxiliary roller and the pressure start operation of the crushing roller are individually controlled , and the pressure applied to the auxiliary roller is completed. Then, by starting the pressurization operation of the grinding roller, the pressurization start operation of the grinding roller is delayed after the pressurization start operation of the auxiliary roller.

(2) In the operation method of the vertical crusher described in (1) , the delay time from the pressing start operation of the auxiliary roller to the pressing start operation of the crushing roller is set in a range from 4 seconds to 8 seconds.

  According to the present invention, when the raw material is finely pulverized, the abnormal vibration generated due to the grinding roller slipping on the bulky raw material layer is suppressed, and the raw material is efficiently pulverized.

It is a figure explaining the whole structure of a vertical crusher in connection with embodiment of this invention. It is a figure explaining arrangement | positioning of a crushing roller, an auxiliary roller, and a rotary table in connection with embodiment of this invention. It is a flowchart explaining the pressurization start timing of an auxiliary roller and a crushing roller according to the embodiment of the present invention. It is a chart which shows the relationship of the timing of the press operation | movement of an auxiliary | assistant roller and a grinding | pulverization roller, the thickness of a raw material layer, and a vibration state concerning embodiment of this invention. It is a figure which shows the relationship between the pressurization time difference (delay time of roller pressurization instruction | indication timing) of an auxiliary | assistant roller and a grinding | pulverization roller, and a vibration state concerning embodiment of this invention. It is a conceptual diagram explaining the relationship between a crushing roller and a raw material layer in connection with this embodiment. It is a reference figure which shows the relationship between the raw material layer layer thickness under an auxiliary roller, and an apparent dynamic friction coefficient. It is a reference figure which shows the relationship of the apparent dynamic friction coefficient between the roller and raw material layer which change with the rotational speed of a roller. It is a reference figure which shows the relationship of the apparent dynamic friction coefficient between the roller and raw material layer which change with the pressure densities of a raw material layer. It is a figure which shows the vibration state by the prior art which carries out the pressurization start operation | movement of an auxiliary roller and a grinding roller simultaneously.

Hereinafter, an example of a preferred embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 to FIG. 5 show a preferred example according to the embodiment of the present invention. FIG. 1 is a conceptual diagram for explaining the overall configuration of a vertical crusher. FIG. It is a figure explaining arrangement | positioning of an auxiliary roller and a rotary table. FIG. 3 is a diagram for explaining the pressing start timing of the auxiliary roller and the crushing roller. FIG. 4 is a chart showing the relationship between the pressing operation timing of the auxiliary roller and the crushing roller, the thickness of the raw material layer, and the vibration state. FIG. 5 is a diagram showing the relationship between the pressure time difference between the auxiliary roller and the grinding roller (the delay time of the grinding roller pressure instruction timing with respect to the auxiliary roller pressure instruction timing) and the vibration state.

  FIGS. 6 to 10 are reference diagrams for reference in understanding the present invention. FIG. 6 is a diagram for explaining the relationship between the roller and the material layer. FIG. 7 is a diagram of the material layer under the auxiliary roller. FIG. 8 is a diagram showing the relationship between the layer thickness and the apparent dynamic friction coefficient, FIG. 8 is a diagram showing the relationship between the apparent dynamic friction coefficient between the roller and the raw material layer, which varies with the rotational speed of the roller, and FIG. 9 is the pressure density of the raw material layer. FIG. 10 is a diagram showing a vibration state of a conventional vertical crusher in which the auxiliary roller and the crushing roller are simultaneously started to pressurize. is there.

Hereinafter, the preferable structure of the vertical crusher 1 which concerns on this embodiment is demonstrated.
The vertical crusher 1 used in the present embodiment is attached to the casings 1B and 1A forming the outline of the vertical crusher 1 and the vertical crusher casing, as shown in FIG. Vibration sensor S1, rotating table 2 driven by a reduction gear 2B and a drive motor 2M installed at the bottom of the vertical crusher 1, and a conical crushing roller 3 that rotates following the rotation table 2 (drawing) In some cases, the auxiliary roller 5 is provided.
Further, the vertical crusher 1 shown in FIG. 1 includes an inverter power supply as a driving power source for the drive motor 2M, and a variable speed vertical mold in which the rotation speed of the rotary table 2 can be arbitrarily changed during operation. A crusher 1.

As shown in FIG. 2 (1), two crushing rollers 3 of the vertical crusher 1 used in this embodiment are arranged on the upper surface of the rotary table 2 so as to be pressed in the direction of the rotary table 2. It is comprised, and when the turntable 2 rotates, it rotates following the turntable 2 via the raw material. Further, in the vertical pulverizer 1 used in the present embodiment, two auxiliary rollers 5 are arranged such that the phase is shifted by 90 degrees with respect to the pulverizing roller 3. 2 is rotated following the raw material.
In the present embodiment, a roller smaller than the grinding roller 3 is used as the auxiliary roller 5 .

  Here, as shown in FIG. 2 (2), the crushing roller 3 is attached to the swing lever 3A and is pivotally supported by the casing 1B so as to be rotatable about the shaft 3C. The arm 3B of the swing lever 3A is supported by the arm 3B. A first hydraulic cylinder 3D is attached. The hydraulic unit 55 shown in FIG. 1 is connected to the first hydraulic cylinder 3D via a hydraulic line (not shown). In the present embodiment, by operating the hydraulic unit 55 to increase the hydraulic pressure of the hydraulic oil flowing in the hydraulic line connected to the first hydraulic cylinder 3D, the hydraulic cylinder 3D is operated to drive the arm 3B. The swing lever 3A is moved to press the crushing roller 3 against the rotary table 2 with a desired pressure.

  Similar to the crushing roller 3, the auxiliary roller 5 is attached to the swing lever 5A and is pivotally supported by the casing 1B so as to be rotatable about the shaft 5C. The arm 5B of the swing lever 5A has a second hydraulic cylinder 5D. Is attached. The hydraulic unit 55 shown in FIG. 1 is connected to the second hydraulic cylinder 5D via a hydraulic line (not shown). In the present embodiment, the hydraulic unit 55 is operated to increase the hydraulic pressure of the hydraulic oil flowing in the hydraulic line connected to the second hydraulic cylinder 5D, thereby operating the hydraulic cylinder 5D to drive the arm 5B. Thus, the swing lever 5A is moved to press the auxiliary roller 5 against the rotary table 2 with a desired pressure.

Hereinafter, the control device 50 will be described as a hydraulic control mechanism for individually controlling the grinding roller 3 and the auxiliary roller 5.
The vertical crusher 1 shown in FIG. 1 includes the above-described hydraulic unit 55 and a controller 50 that controls the hydraulic unit 55 to control the pressure applied to the auxiliary roller 5 and the crushing roller 3. The apparatus 50 has a setting device 51 that can set the pressurization start timing and the pressurizing force separately for the auxiliary roller 5 and the crushing roller 3, respectively, and a timer device 53 that measures the time related to the auxiliary roller 5 and the pressurization start timing of the crushing roller. And a control unit 52 for transmitting a predetermined command signal to the hydraulic unit 55 when the time set in the setter 51 and the timer time set in the timer 53 are compared or calculated to satisfy the condition. ing.
The control device 50 controls the hydraulic unit 55 with the above-described configuration to individually control the hydraulic pressure of the hydraulic oil to be sent to the first hydraulic cylinder 3D and the second hydraulic cylinder 5D. For 5, the lowering timing, pressurization start timing and pressurizing force are individually controlled.
In the embodiment shown in FIG. 1, the vibration sensor S1 is provided to constantly monitor the state of vibration generated in the vertical crusher during operation, and in the event that abnormal vibration is detected, a safety device is provided. And the operation of the vertical crusher 1 is stopped by activating the interlock.

Hereinafter, the internal structure of the vertical crusher 1 will be described.
The vertical crusher 1 shown in FIG. 1 includes an internal cone 19 having a substantially inverted conical shape above the rotary table 2, and a fixed primary classifying blade 14 and an internal cone 19 above the internal cone 19. And a rotary classifier 13 having a rotary classifying blade inside the primary classifying blade 14.
The rotary blades provided in the rotary classifier 13 are driven by a drive motor (not shown) installed at the top of the vertical crusher 1 so as to freely rotate.

  Furthermore, the vertical crusher 1 shown in FIG. 1 includes a gas supply port 33 for introducing gas below the rotary table 2 and a lower outlet 34 for taking out an extremely heavy material. An upper outlet 39 is provided above the rotary table so that the product can be taken out together with the gas.

  The vertical crusher 1 shown in FIG. 1 has the above-described configuration, and by introducing gas (air in the present embodiment) from the gas supply port 33 during operation, the primary classification blades 14 and 14 A gas stream that passes through the rotary classifier 13 and flows to the upper outlet 39 is generated.

  The raw material pulverized on the rotary table 2 is blown up by the gas and moves up in the casing and flows in the direction of the primary classification blade 14, but the raw material having a large diameter and a large weight falls without reaching the primary classification blade 14. Then, it is pulverized again on the rotary table 2. The extremely heavy raw material is discharged out of the machine from the lower outlet 34 at the lower part of the vertical crusher 1.

  The raw material that has passed through the primary classifying blade 14 and failed to pass through the rotary classifier 13 falls on the internal cone 19 and is supplied to the vicinity of the central portion of the rotary table 2 and is pulverized again on the rotary table 2. . On the other hand, the raw material having a small diameter that has passed through the rotary classifier 13 is taken out from the upper outlet 39 as a product. Even after being pulverized by the pulverizing roller 3, the raw material supplied to the rotary table 2 and pulverized again without passing through the primary classifying blade 14 or the rotary classifier 13 is a circulating raw material. Called.

Hereinafter, a preferable example of the operation method of the vertical crusher 1 according to the present embodiment will be described. In the operation method of the vertical pulverizer 1 according to the present embodiment, before the operation of the vertical pulverizer 1 is started, the pressing start timing of the auxiliary roller 5 and the pulverizing roller 3 is set in advance with respect to the setting device 51 of the control device 50. input.
Specifically, taking into account the time until the thickness of the raw material layer is secured to the extent that the auxiliary roller 5 can be lowered onto the rotary table 2 after the raw material is charged, Sets the time for transmitting the auxiliary roller lowering instruction signal.
In addition, about the time when the thickness of the raw material layer required at the minimum for lowering the auxiliary roller 5 is secured differs depending on the state of the raw material placed on the rotary table 2 at the time of activation, depending on the situation at the time of activation. Adjustment is required.

  Next, the time from when the lowering instruction signal is transmitted to the auxiliary roller 5 until the lowering instruction signal is transmitted to the crushing roller 3 is set as the timer T1, and the lowering instruction signal is transmitted to the auxiliary roller 5. The time from when the pressure command signal is transmitted to the auxiliary roller 5 is set as the timer T2. Then, a time from when the lowering instruction signal to the pulverizing roller 3 is transmitted until the pressurizing instruction signal to the pulverizing roller 3 is transmitted is set as a timer T3.

  In this embodiment, the time from when the pressure instruction signal is transmitted to the auxiliary roller 5 to when the pressure instruction signal is transmitted to the crushing roller 3 is ΔT, and pressurization of the auxiliary roller 5 is started. After ΔT from the operation, the timer T1, the timer T2, and the time of the timer T3 are set in the setting device 51 so that the pressing operation of the crushing roller 3 is started.

  Hereinafter, after the operation of the vertical pulverizer 1 is started, the raw material (coal which is a material to be pulverized in this embodiment) input to the raw material input port 35 of the vertical pulverizer 1 is rotated through the raw material input chute. It is thrown near the center of the table 2 and moves to the outer peripheral side of the rotary table 2 while drawing a spiral trajectory.

  After the raw material is charged, when the raw material reaches the rotary table 2 to form a raw material layer, a lowering instruction signal for the auxiliary roller 5 is transmitted from the control device 50, and the hydraulic unit 55 is controlled to operate the hydraulic cylinder 5D. Then, the auxiliary roller 5 is slowly lowered to the rotary table 2 side. The timer T1 and the timer T2 start timing simultaneously with the lowering instruction signal of the auxiliary roller 5, and after the set time of the timer T1 has elapsed, the lowering instruction signal is transmitted to the grinding roller 3 and the timer T2 After the set time elapses, a pressure instruction signal to the auxiliary roller 5 is transmitted. Then, after the pressurization of the auxiliary roller 5 is completed, the set time of the timer T3 elapses, and a pressurization instruction signal to the grinding roller 3 is transmitted.

During the operation of the vertical pulverizer 1, the raw material charged into the raw material inlet 35 of the vertical pulverizer 1 is. It is thrown into the vicinity of the center of the turntable 2 via the raw material throwing chute and moves to the outer peripheral side of the turntable 2 while drawing a spiral trajectory. The raw material charged on the rotary table 2 is combined with the circulating raw material, which will be described later, on the rotary table 2, and most of the raw material is compressed by the auxiliary roller 5 and degassed, and then the rotary table 2 and the grinding roller 3. And is crushed.
The material crushed by being smashed by the rotary table 2 and the pulverizing roller 3 passes over the dam ring 15 provided around the outer edge of the rotary table 2 and is a gap between the outer peripheral portion of the upper surface 2 of the rotary table and the casing. It goes to the annular passage 30 (sometimes referred to as an annular space 30).

The raw material that has reached the annular passage 30 is blown up by the gas and rises in the casing and tends to flow in the direction of the primary classification blade 14, but the raw material having a large diameter and a large weight reaches the primary classification blade 14. However, most of them fall on the turntable 2 and are crushed again.
In addition, among the raw materials that cannot pass through the primary classification blade 14, those that are extremely heavy fall down to the lower side of the rotary table 2 and are taken out from the lower outlet 34 as waste stone. In addition, the raw material that has passed through the primary classifying blade 14 and failed to pass through the rotary classifier 13 is collected by the internal cone 19 by being dropped, supplied again to the rotary table 2 and pulverized. .

  Here, when the raw material is finely pulverized, it is necessary to reduce the diameter of the raw material that can pass through the rotary classifier 13, and as a result, the primary classifying blade 14 or the rotary classifier 13 cannot pass through and falls. The ratio of the raw material to be increased increases, the ratio of the circulating raw material repeatedly pulverized to the new raw material input from the raw material input chute increases, and a bulky raw material layer is formed.

  The circulating raw material is repeatedly supplied onto the rotary table until it reaches a predetermined particle size and discharged outside the machine, and is entrapped and pulverized by the rotary table 2 and the pulverizing roller 3. On the other hand, the raw material pulverized small to a predetermined particle size passes through the rotary classifier 13 and is taken out as a pulverized product from the upper outlet 39.

  As described above, when fine pulverization is performed in the vertical pulverizer 1, separately from the new raw material, the circulating raw material that falls through the primary classifying blade 14 or the rotary classifier 13 and circulates inside is increased. . Naturally, the more the raw material is pulverized, the more the proportion of the internal circulating raw material increases. However, the circulating raw material is bulky because it is smaller in diameter than the new raw material, and fine voids are generated in the raw material layer. In addition, the amount of gas carried in the gap inevitably increases.

  FIG. 7 shows an apparent relationship between the thickness of the raw material layer under the auxiliary roller and the dynamic friction coefficient between the rollers. In terms of the dynamic friction coefficient, the thicker the layer, the smaller.

  FIG. 8 shows the relationship between the roller speed and the apparent dynamic friction coefficient between the raw material layer and the roller. As for the dynamic friction coefficient, except for some extremely slow regions, the finer particle size is smaller in terms of the dynamic friction coefficient.

  FIG. 6 shows a conceptual diagram, in which a layer containing a large amount of gas is present in the raw material layer, and a slippery portion is formed. When the raw material is finely pulverized, the pulverized roller pulverizes the recycled raw material with a large gap for holding the gas and the new raw material together, causing slippage between the layers, leading to abnormal vibration. It becomes impossible to drive.

  Here, the relationship between the thickness of the raw material layer under the roller and the vibration state is shown in the chart of FIG. When the crushing roller 3 and the auxiliary roller 5 are simultaneously pressed by the same roller pressurization instruction signal, the motor current value of the rotary table 2 starts to increase, and at the same time, the vibration suddenly increases and the operation is impossible. The motor has tripped due to abnormal motor current.

In the case of this embodiment, the relationship between the pressure start timing of the auxiliary roller 5 and the grinding roller 3, the thickness of the raw material layer, and the vibration state is shown in the chart of FIG.
In the present embodiment, a timer is provided so that the pressure instruction signal for the grinding roller 3 is transmitted ΔT seconds after the pressure instruction signal is transmitted to the auxiliary roller 5 (6 seconds in the present embodiment). T1 to timer T3 were set. In the present embodiment in which the crushing roller 3 is started to be pressed after a lapse of a set time after the auxiliary roller 5 starts to pressurize, the vibration does not suddenly increase and stable operation is possible.

    The relationship between ΔT and vibration is shown in FIG. It can be seen that the vibration increases when ΔT, which is the delay time from the pressurization start operation of the auxiliary roller 3 to the pressurization start operation of the grinding roller 5, is too short or too long. Assuming that the maximum vibration amplitude value is 100 μm or less as a region where stable operation is possible, a preferable time range of ΔT is a range from 4 seconds to 8 seconds, and particularly preferably 6 seconds.

FIG. 7 shows the relationship between the thickness of the raw material layer under the auxiliary roller and the dynamic friction coefficient.
Immediately after the start of pressurization of the auxiliary roller 5, the pressurizing force of the auxiliary roller 5 is not sufficiently increased and the pressure density is 70% or less, assuming that the pressurizing state is completely increased. Since it is still slippery, it is presumed that abnormal vibration has occurred in the prior art in which the crushing roller 5 and the auxiliary roller 3 are started to press simultaneously.

  On the other hand, if the operation is continued in a state where the pressure is applied only to the auxiliary roller 5 and the pulverizing roller 3 is not functioning, the balance between the supply of raw materials and the pulverizing ability is lost to cause abnormal vibration. It is presumed that it is not preferable to delay the pressing start operation of the crushing roller 3.

  As described above, the operation method of the vertical crusher according to the present invention can be particularly preferably used when the raw material is finely pulverized using the auxiliary roller and the pulverizing roller.

DESCRIPTION OF SYMBOLS 1 Vertical crusher 2 Rotary table 3 Crushing roller 3A Swing lever 3B Arm 3C shaft 3D 1st hydraulic cylinder 5 Auxiliary roller 5A Swing lever 5B arm 5C shaft 5D 2nd hydraulic cylinder 13 Rotary classifier 14 Primary classifying blade 15 Dam ring 19 Internal cone 35 Raw material inlet 39 Upper outlet 50 Hydraulic 55 control device 51 Setting machine 52 Control unit 53 Timer device 55 Hydraulic unit S1 Vibration sensor

Claims (2)

A method of operating a vertical crusher comprising a crushing roller, an auxiliary roller, and a rotary table, wherein the raw material charged on the rotary table is compacted and degassed by the auxiliary roller and then crushed by the crushing roller,
The auxiliary roller is made smaller than the crushing roller , and when the vertical crusher is started, the pressure start operation of the auxiliary roller and the pressure start operation of the crushing roller are individually controlled , and the pressure applied to the auxiliary roller is completed. The operation method of the vertical pulverizer in which the pressurizing operation of the pulverizing roller is started later than the pressurizing start operation of the auxiliary roller by performing the pressurizing start operation of the pulverizing roller after that . The method for operating the vertical crusher according to claim 1, wherein a delay time from the pressure start operation of the auxiliary roller to the pressure start operation of the crushing roller is in a range from 4 seconds to 8 seconds.

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