JP7205690B2 - Vertical grinder - Google Patents

Description

The present invention mainly grinds coal, oil coke, limestone, slag, clinker, cement raw materials, other inorganic raw materials, or organic raw materials such as chemicals and biomass into powder with a driven crushing roller on a rotary table. The present invention relates to a vertical pulverizer, and more particularly to a vertical pulverizer equipped with a means for sprinkling water on raw materials in order to reduce vibration of pulverizing rollers.

Vertical pulverizers are widely used as pulverizers for pulverizing raw materials such as blast furnace slag, cement, coal, and biomass. A conventional vertical pulverizer is equipped with a rotary table in a casing that forms the outer shell of the pulverizer, and a plurality of pulverizing rollers and sub-rollers arranged at positions that equally divide the outer periphery of the upper surface of the rotary table in the circumferential direction. ing.
In such a vertical pulverizer, when raw material to be pulverized is supplied to the center of the rotary table, the raw material to be pulverized moves to the outer peripheral portion of the rotary table due to the rotation of the rotary table. Since the crushing rollers are pressed against and rotate at the outer peripheral portion, the raw material to be crushed enters between the crushing rollers and the rotary table and is crushed. The hot air blowing up from the annular passage between the outer peripheral surface of the rotary table and the inner peripheral surface of the casing dries the powder together with the hot air, and rises in the casing. The granules are sorted by classifying means provided in the upper part of the casing, and products having a predetermined grain size are discharged to the outside. Coarse powder that cannot pass through the classifying means falls on the rotary table again and is pulverized.

FIG. 6 is an explanatory diagram of vibration generation in the vertical pulverizer. In the vertical pulverizer, when the pulverized raw material on the rotary table has a predetermined layer thickness, the pulverizing roller maintains a predetermined number of revolutions synchronized with the rotation of the table and becomes a stable steady state ((a) in FIG. 6 reference).
Normally, the crushing roller should rotate at a rotational speed synchronized with the rotation of the table, but if the crushing roller slips or slips between the layers of the crushed raw material that are caught, the rotation speed decreases accordingly. Sometimes. As a result, the layer thickness of the crushing roller becomes low (thin) (see (b) in FIG. 6).
If such a state continues, the crushing roller completely slips at a certain moment, and the number of revolutions of the crushing roller stops momentarily. As a result, although the crushing roller stops rotating (does not get caught), the particle groups are supplied one after another onto the rotary table, so the crushing roller is largely pushed upward (see (c) in FIG. 6). ).
The pulverizing roller, which is greatly pushed upward, then drops abruptly onto the rotary table due to its recoil (see (d) in FIG. 6).
This up-and-down motion spreads without convergence, and the violent rocking of the crushing roller becomes a vibration source, causing mill vibration (see (e) in FIG. 6). Mill vibrations adversely affect operations such as roller wear, vibration, and noise.

Conventionally, in order to reduce such mill vibrations, there have been various vertical pulverizers provided with water sprinkling means capable of reducing the occurrence of slippage of the pulverizing rollers by adding water to the pulverized raw material inside or outside the pulverizer.
Among them, the water content of the pulverized raw material being conveyed is measured, and a water sprinkler that sprinkles water based on the measured value is provided outside the vertical pulverizer (see Patent Document 1) (see Patent Document 1). It is not desirable because it increases. For this reason, the mainstream configuration is provided with a sprinkler for spraying water on the upper surface of the rotary table inside the crusher and near the raw material chute (see Patent Documents 2 and 3).
FIG. 7 is an explanatory view of a conventional vertical pulverizer provided with water sprinkling means inside a casing. As shown in the figure, the conventional watering means (watering device 1 in the figure) has a structure in which a watering nozzle 3 is provided for each crushing roller 2, and each watering nozzle 3 is connected to a branch pipe 5 from a unified watering pump 4. We are hiring. Such a water sprinkler 1 is provided with a flow meter 6 downstream of the water pump 4 and automatically controls a flow rate adjustment valve 7 so as to achieve a predetermined flow rate. At this time, the total flow rate of all the water nozzles 3 (for example, three water nozzles in the case of three water nozzles) is collectively controlled.

In order to prevent the occurrence of mill vibration, when the state of (b) in FIG. ) is desirable.
Condition (b), which is a precursor to mill vibration, may result in a reduction in the number of rotations of only one particular grinding roller, such as any one of the three grinding rollers. This is because the amount and condition of the raw material supplied to each crushing roller is not uniform due to the position where the raw material is supplied to the upper surface of the rotary table and the effect of hot air blowing up from the outer circumference of the table. In addition, since the operating state of the crusher changes each time, the crushing roller falling into the state (b) is not always in the same place.
The conventional water spraying means is configured to control only the total flow rate of water spraying, and water is sprayed not only on the rollers of the plurality of crushing rollers whose rotational speed has decreased, but also on the rollers in a steady state, resulting in a large amount of water spraying. end up Therefore, in the case of cement grinding, for example, the quality of cement deteriorates. Moreover, the amount of energy required for the drying process after pulverization will increase. In addition, if the operator does not notice the decrease in the number of revolutions of the crushing roller, a vibration trip may occur, which may affect the operating cost.

Japanese Patent No. 2655022 Japanese Utility Model Publication No. 4-33954 JP-A-9-215936

The problem to be solved by the present invention is to provide a vertical pulverizer capable of efficiently pulverizing by reducing the amount of water sprinkled in the pulverizing process in view of the above-described problems of the conventional technology.

As a first means for solving the above-described problems, the present invention provides a vertical pulverizer in which a plurality of pulverizing rollers in contact with each other on a rotary table are driven to pulverize the raw material to be pulverized,
a water sprinkling means having a sprinkling nozzle for sprinkling water on the pulverized raw material immediately before pulverization by the pulverizing roller on the upper surface of the rotary table, and adjusting the amount of water sprayed from the water sprinkling nozzle for each of the pulverizing rollers ;
a roller rotation detector capable of detecting the number of revolutions of each of the crushing rollers;
a control unit electrically connected to the roller rotation detector and the water spraying means, and capable of increasing the amount of water sprayed by the water spraying means based on the detected number of revolutions when the number of revolutions is less than a predetermined number of revolutions;
The control unit increases the amount of water sprayed by the water spraying means during steady operation and controls the roller rotation speed to be equal to or higher than a set value, and then performs control to return the amount of water sprayed to the initial amount after a lapse of a predetermined time. To provide a vertical pulverizer for
According to the above-described first means, among the plurality of crushing rollers, for example, only a specific crushing roller whose roller rotation speed has decreased can efficiently sprinkle water on the immediately preceding crushed raw material. Therefore, excessive water is not sprayed on the pulverized raw material immediately before another pulverizing roller in a steady state, and the total amount of water sprayed by the water sprinkling means can be reduced.

As a second means for solving the above problems, the present invention provides, in the first means, a roller rotation detector capable of detecting the number of revolutions of each of the crushing rollers;
a control unit electrically connected to the roller rotation detector and the water spraying means, and capable of increasing the amount of water sprayed by the water spraying means based on the detected number of revolutions when the number of revolutions is less than a predetermined number of revolutions; To provide a vertical pulverizer characterized by:
According to the second means, it is possible to efficiently sprinkle water on the pulverized raw material in front of only the pulverizing rollers of the plurality of pulverizing rollers that do not meet the predetermined number of revolutions. Therefore, excessive water is not sprayed on the raw material to be pulverized immediately before the pulverizing rollers in a steady state, and the total amount of water sprayed by the water sprinkling means can be reduced.

As a third means for solving the above problems, the present invention provides, in the second means, the roller rotation detector detects the number of rotations of a sub-roller provided upstream of the crushing roller, output is possible, and the control unit is capable of controlling to increase the amount of water sprayed by the water spraying means based on the detected value of the rotation speed of the sub -roller when the rotation speed is less than a predetermined rotation speed. is to provide
According to the third means, water can be efficiently sprinkled only on the crushed raw material in front of only the crushing rollers and/or sub-rollers that do not meet the predetermined number of rotations among the plurality of crushing rollers and/or sub-rollers. Therefore, excessive water is not sprayed on the raw material to be pulverized immediately before the pulverizing rollers in a steady state, and the total amount of water sprayed by the water sprinkling means can be reduced. This makes it possible to prevent sudden vibrations.

The present invention is a fourth means for solving the above problems, in the second or third means, wherein the control unit increases the amount of water sprayed by the water spraying means so that the roller rotation speed becomes equal to or higher than a set value. To provide a vertical pulverizer characterized by performing control to return to the initial water sprinkling amount after a predetermined time has elapsed after performing control.
According to the fourth means, after the roller rotation speed reaches the predetermined rotation speed, the water sprinkling means, which has increased the water sprinkling amount due to insufficient rotation speed of the roller, can be returned to the initial amount of water sprinkling, and the crushed raw material can be replenished. Excess watering can be prevented.

According to the present invention, it is possible to prevent vibration by increasing the amount of water sprinkled at the stage of predicting the occurrence of vibration when the number of rotations of the roller decreases, and also reduce adverse effects (roller wear, vibration, noise) on operation due to sudden vibration. can do.
Also, the total amount of water sprayed by the water spraying means can be reduced. As a result, the quality of pulverized products can be improved and the energy required for drying can be greatly reduced.

It is an explanatory view of the water sprinkler of the vertical pulverizer of the present invention. FIG. 4 is an explanatory diagram of a proximity switch; It is a control processing flow chart of the vertical pulverizer of the present invention. It is a graph which shows the relationship between the amount of water sprinkling, the layer thickness of a crushing roller, or sub-roller rotation speed. It is a structural schematic diagram of a vertical pulverizer. FIG. 4 is an explanatory diagram of vibration generation in a vertical pulverizer; FIG. 2 is an explanatory diagram of a conventional vertical pulverizer provided with a water sprinkling means inside a casing.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a vertical pulverizer of the present invention will be described in detail below with reference to the drawings.
[Vertical crusher 10]
FIG. 5 is a schematic diagram of the structure of a vertical pulverizer (sub-rollers and water sprinkling means are not shown). As shown in the figure, the vertical pulverizer 10 includes a casing 12, a rotary table 14, a plurality of pulverizing rollers 16 arranged at positions equally dividing the outer periphery of the upper surface of the rotary table 14 in the circumferential direction, and the rotary table 14. , a classifying means 30 provided on the upper portion of the casing 12, and a dam ring 48 attached to the outer peripheral edge of the rotary table 14.
The crushing roller 16 is connected to a piston rod of a hydraulic cylinder 24 via an upper arm 20 rotatably pivoted to the lower casing 12B serving as a fulcrum and a lower arm 22 integrally formed with the upper arm 20. . The pulverizing roller 16 is pressed against the upper surface 14A of the rotary table by the operation of the hydraulic cylinder 24, and rotates by being driven by the rotary table 14 through the raw material to be pulverized.
Classifying means 30 is provided above the rotating table upper surface 14A of the casing 12 .

The classifying means 30 includes a rotating shaft 30a, rotating blades 30b, and fixed blades 30c. The rotary shaft 30a hangs downward from the upper surface of the casing 12 and is rotatable by an external drive motor (not shown). A plurality of rotating vanes 30b are formed in a ring shape around the rotating shaft 30a below the rotating shaft 30a. Furthermore, a plurality of fixed blades 30c are formed side by side on the outer circumference of the rotary blade 30b. Both the rotating blades 30b and the fixed blades 30c are arranged so that their longitudinal directions are parallel to the axis of the rotating shaft 30a. supplied from In the classifying means 30 having such a configuration, the rotating blade 30b rotates together with the rotating shaft 30a, and only fine particles (fine powder) that have passed through the fixed blade 30c and the rotating blade 30b are discharged from the upper outlet 44.
An internal cone 30e and a feed pipe 30f are provided at the lower end of the fixed blade 30c. The internal cone 30e is formed in a funnel shape whose diameter decreases from the top to the bottom, and the feed pipe 30f is formed in a cylindrical shape connected to the lower end of the internal cone 30e. It has a structure in which the body is captured and supplied to the upper surface 14A of the rotary table from the lower discharge port via the feed pipe 30f.

A raw material charging chute 34 is connected to the inner cone 30e. Through this raw material charging chute 34, the raw material is charged from the raw material charging port 32 onto the upper surface 14A of the rotary table.
The raw material charged from the raw material charging chute 34 moves to the outer peripheral portion of the rotary table top surface 14A while drawing a spiral trajectory on the rotary table top surface 14A, and is caught between the rotary table top surface 14A and the grinding roller 16 to be pulverized. be. A part of the pulverized powder and granular material climbs over the dam ring 48 that is provided around the outer edge of the rotary table upper surface 14A and adjusts the layer thickness of the raw material, and is separated from the outer peripheral portion of the rotary table upper surface 14A and the casing 12. It goes to the annular passage 40 which is a gap. Here, a gas introduction port 42 for introducing hot air heated to a predetermined temperature is provided below the rotary table 14 of the lower casing 12B.

During the operation of the vertical pulverizer 10, by introducing hot air from the gas inlet 42, the hot air flowing from below the rotary table 14 to the upper outlet 44 through the classification means 30 in the casing 12 is reduced. There is air current.
The raw material charged into the vertical pulverizer 10 and part of the granular material pulverized by the rotary table 14 and the pulverizing roller 16 and overcoming a dam ring 48, which will be described later, are blown up by hot air from the annular passage 40. It rises inside the casing 12 and reaches the classifying means 30 .
Here, the powder particles having a large diameter and mass cannot pass through the fixed vane 30c and the rotating vane 30b of the classifying means 30, fall into the inner cone 30e, and are again bitten by the grinding roller 16 to be pulverized. be. On the other hand, the small-diameter particles pass through the space between the fixed blades 30c and the rotary blades 30b arranged with a gap therebetween, pass through the classifying means 30, and are taken out of the casing 12 through the upper outlet 44.
Also, a part of the raw material with the maximum particle size that has reached the circular passage 40 without being caught by the crushing roller 16 falls from the circular passage 40 to the lower part of the rotary table 14 and is vertically crushed from the lower outlet 46. It is taken out of the machine 10.

[Sprinkling means 50]
FIG. 1 is an explanatory diagram of the water sprinkling means of the vertical pulverizer of the present invention.
As an example, three crushing rollers 16 shown in FIG. 1 are arranged at equal intervals on the upper surface 14A of the rotary table. Between the crushing rollers 16, sub-rollers 17 (three units) are arranged at regular intervals. The sub-roller 17 on the upstream side of the rotation of the crushing roller 16 smoothes the crushed raw material on the upper surface 14A of the rotary table supplied to the crushing roller 16 to a predetermined layer thickness so that the crushed raw material is more vibrating than when the crushed raw material is directly supplied to the crushing roller. Occurrence can be reduced.
The water sprinkling means 50 of the present invention is attached to each of the plurality of crushing rollers 16 . More specifically, three sprinkler nozzles 52 are arranged on the upstream side of the crushing roller 16 in the table rotation direction (clockwise in the drawing). The water spray nozzles 52 are arranged in the longitudinal direction along the radial direction from the center of rotation of the rotary table 14 .
A flow meter 56 and a flow control valve 58 are provided on a pipe 54 connecting the water nozzle 52 and the water pump 53 .
The water spray means 50 having such a structure can measure the flow rate from the water pump 53 to the water nozzle 52 with the flow meter 56 and control the flow rate with the flow control valve 58 to a predetermined flow rate. Such flow rate control can be performed by the water spraying means 50 provided for each crushing roller 16 (three in FIG. 1).

[Roller rotation detector 60]
FIG. 2 is an explanatory diagram of the roller rotation detector, (1) is a cross-sectional view, and (2) is a BB arrow view of (1).
The roller rotation detector 60 is a sensor that measures the rotation speed of the crushing roller 16, and as an example, a proximity switch is used in this embodiment. A specific configuration of the roller rotation detector 60 is to provide a cross-shaped rotary plate 62 coaxial with the rotary shaft of the crushing roller 16 . A proximity switch 64 is provided facing the outer circumference of the side surface of the rotary plate 62, and the number of rotations is calculated from the number of detections per unit time. The roller rotation detector 60 constantly monitors the number of revolutions of the crushing roller, and is configured to be able to output the measured value to the control section 70, which will be described later.
In addition, the roller rotation detector 60 is also attached to the sub-roller 17 in a similar configuration to constantly monitor the number of rotations, and the measured value can be output to the control unit 70, which will be described later.

[Control unit 70]
The controller 70 is electrically connected to the sprinkler 50 and the roller rotation detector 60 (electrical connections among the controller 70, the roller rotation detector 60, and the flow meter 56 in FIG. 1 are not shown). . The controller 70 controls the flow rate of the water sprinkling means 50 based on the measured value of the roller rotation detector 60 . More specifically, the control of the control unit 70 monitors the number of revolutions of the crushing rollers 16, and when the number of revolutions of any of the crushing rollers 16 falls below a predetermined number of revolutions (set value), the crushing with the reduced number of revolutions is performed. Control is performed to open the water spray nozzle 52 in front of the roller 16 and increase the water spray amount.
The control unit also has a timer function (with a timer). After increasing the watering amount, the initial value of the watering amount ( control to return to automatic adjustment of watering amount).

FIG. 4 is a graph showing the relationship between the amount of sprinkled water and the layer thickness of the pulverizing roller or the rotational speed of the sub-roller. Factors that reduce the rotation speed of the crushing roller include changes in the properties of the raw material to be crushed and changes in the operating conditions of the crusher. At this time, the rotational speed of the sub-roller is also reduced. As a result, the layer thickness of the pulverizing roller decreases and vibration increases. At this time, when the amount of water sprinkled is increased, the number of revolutions of the sub-rollers increases (square plots in the same graph) and the layer thickness of the pulverizing roller increases (circle plots in the same graph). And the vibration is also reduced.
Based on this result, the control unit 70 receives the measured values of the rotation speed of the crushing roller 16 and the sub-roller 17 from the roller rotation detector 60, monitors whether or not the predetermined rotation speed is satisfied, and determines whether any of the crushing rollers 16 Or/and when the number of revolutions of the sub-roller 17 falls below a predetermined number of revolutions (set value), the crushing roller 16 whose number of revolutions has decreased or the water spray nozzle 52 in front of the crushing roller 16 on the rotation downstream side of the sub-roller whose number of revolutions has decreased to control the amount of water sprinkled.
[Action]
The operation of the vertical pulverizer of the present invention configured as described above will be described below.
FIG. 3 is a control processing flow chart of the vertical pulverizer of the present invention.
Step 1: Start up the vertical pulverizer 10, keep the pulverizing roller 16 at a predetermined number of revolutions synchronized with the rotation of the table, and reach a stable steady state of operation.
Step 2: Switch to automatic watering amount adjustment. Examples of set values include the (initial) amount of water sprayed during steady operation (A: t/h), the increased amount of water sprayed when the roller rotation speed decreases (B: t/h), and the product or drying energy. The upper limit of water spray amount (C: t/h), the number of roller rotations during stable operation (D: rpm), and the water spray increase holding time (E: minutes) can be set in advance.
Step 3: Check the presence or absence of raw materials to be crushed into the crusher.
Step 4: If there is a raw material to be pulverized in step 3, it is confirmed whether or not the number of rotations of the pulverizing roller 16 and/or the sub-roller 17 provided with the roller rotation detector 60 is equal to or higher than a set value (D: rpm). If the number of revolutions is equal to or higher than the set value (D: rpm), steady operation is maintained, and the steps from step 3 are repeated.
Step 5: When the roller rotation speed in step 4 is equal to or less than the set value D, the amount of water sprinkled by the water sprinkling means 50 in front of the crushing roller on the downstream side of the rotation of the crushing roller whose rotation speed is reduced or the sub-roller whose rotation speed is lowered (B: t /h).

Step 6: After increasing the amount of water sprinkled in step 5, it is checked whether the number of rotations of the crushing roller or sub-roller provided with the roller rotation detector 60 is equal to or higher than the set value (D: rpm).
Step 7: If the roller rotation speed in step 6 is equal to or greater than the set value D, the timer of the control unit 70 measures the watering increase holding time (E minutes).
Step 8: After the time in step 7 has elapsed, restore (decrease) the watering rate to the set value (At/h). After that, the process from step 3 is repeated.
Step 9: If the roller rotation speed in step 6 is smaller than the set value D, it is confirmed whether or not the amount of sprinkled water is equal to or less than the upper limit (Ct/h). If the amount of watering is equal to or less than the upper limit, the process from step 5 is repeated.
Step 10: When the water sprinkling amount (Ct/h) is larger than the upper limit value in step 9, a warning is displayed and the operation is shifted to manual operation by the operator. After that, processing such as stopping the crusher is performed. Also, in the presence or absence of pulverized raw material in step 3, if there is no raw material, the process ends.
According to the vertical pulverizer of the present invention, the amount of water sprinkled is increased at the sign of vibration occurrence when the rotation speed of the roller decreases, and vibration can be prevented, and adverse effects on operation due to sudden vibration (roller wear , vibration and noise) can also be reduced.
Also, the total amount of water sprayed by the water spraying means can be reduced. As a result, the quality of pulverized products can be improved and the energy required for drying can be greatly reduced.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention.
Moreover, the present invention is not limited to the combinations shown in the embodiments, and can be implemented in various combinations.

1 Sprinkler 2 Crushing Roller 3 Sprinkling Nozzle 4 Sprinkling Pump 5 Branch Pipe 6 Flow Meter 7 Flow Control Valve 10 Vertical Crusher 12 Casing 12B Lower Casing 14 Rotary Table 14A Rotary Table Upper Surface 16 Crushing Roller 17 Sub-Roller 20 Upper Arm 22 Lower Arm 24 hydraulic cylinder 30 classifying means 30a rotating shaft 30b rotating vane 30c fixed vane 30e internal cone 30f feed pipe 32 raw material input port 34 raw material input chute 40 annular passage 42 gas inlet 44 upper outlet 48 dam ring 50 watering means 52 watering nozzle 53 Sprinkling pump 54 Piping 56 Flow meter 58 Flow control valve 60 Roller rotation detector 62 Rotating plate 64 Proximity switch 70 Control unit

Claims (2)

A vertical pulverizer in which a plurality of pulverizing rollers in contact with a pulverized raw material on a rotary table are driven to pulverize the pulverized raw material,
a water sprinkling means having a sprinkling nozzle for sprinkling water on the pulverized raw material immediately before pulverization by the pulverizing roller on the upper surface of the rotary table, and adjusting the amount of water sprayed from the water sprinkling nozzle for each of the pulverizing rollers ;
a roller rotation detector capable of detecting the number of revolutions of each of the crushing rollers;
a control unit electrically connected to the roller rotation detector and the water spraying means, and capable of increasing the amount of water sprayed by the water spraying means based on the detected number of revolutions when the number of revolutions is less than a predetermined number of revolutions;
The control unit increases the amount of water sprayed by the water spraying means during steady operation and controls the roller rotation speed to be equal to or higher than a set value, and then performs control to return the amount of water sprayed to the initial amount after a lapse of a predetermined time. vertical grinder. The vertical pulverizer according to claim 1,
The roller rotation detector detects the number of revolutions of a sub-roller provided in the preceding stage of the crushing roller, and can output to the control unit. A vertical pulverizer characterized in that it is controllable to increase the amount of water sprayed by said water spraying means when the number of pulverizers is less than the number.

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