JPH0578387B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a vertical pulverizer that pulverizes cement raw materials, coal, chemicals, etc. through cooperation between a rotating table and pulverizing rollers.

[Prior Art] Vertical pulverizers equipped with a rotary table and rollers are widely used as a type of pulverizer for finely pulverizing powders such as cement raw materials, coal, and chemicals. This type of crusher consists of a disk-shaped rotary table that is driven by a motor with a reducer and rotates at a low speed in the lower part of a cylindrical casing, and a part that divides the outer circumference of the upper surface equally in the circumferential direction, which is pressed by hydraulic pressure or the like. It is equipped with a plurality of rollers that are driven to rotate. The powder as a raw material supplied to the center of the rotary table through the supply pipe receives a centrifugal force in the radial direction of the table due to the rotation of the table, and as it slides on the table, it receives a force in the rotational direction from the table. The table rotates somewhat slower than the table rotation speed. The above two forces, that is, the forces in the radial direction and the force in the rotational direction are combined, and the powder moves to the outer circumference of the rotary table while drawing a spiral trajectory on the table. Since the roller is in pressure contact with this outer periphery and is rotating, the particles with spiral lines enter between the roller and the rotary table from a direction forming a certain angle with the roller axis direction and are bitten. Shattered.

On the other hand, hot air is guided to the base of the casing by a duct, and the fine powder is dried by blowing up the hot air from the annular space between the outer circumferential surface of the rotary table and the inner circumferential surface of the casing. It rises inside the casing, and is discharged from the outlet as a mixture with hot air and sent to the next process.

As the structure within the annular space for blowing up the hot air from the annular space, a rotating blade that blows up the hot air while swirling it in a tornado shape has conventionally been widely used.

However, the material to be crushed that is supplied to the crusher as described above is rarely crushed to the fineness required by the crusher if it is subjected to the crushing action by the crushing rollers only once. In addition, not all objects to be crushed that fall into the center of the rotary table are bitten by the crushing rollers, so the powder particles that reach the outer edge of the rotary table rise up on the hot air currents blown up from the annular space. However, depending on the particle size, the particles may fall down or be classified and rejected by the separator before reaching the separator installed at the top of the crusher and returned to the rotary table. Therefore, the granules and powder in the pulverizer do not simply flow in one direction from the bottom to the top, but form a type of circulating flow extending above and below the pulverizer.

[Problems to be Solved by the Invention] However, such a conventional hot air blowing mechanism has the following problems.

In other words, the material to be crushed that is constantly fed into the crusher rises from the rotary table to the separator, or moves between the rotary table and the separator until it reaches the required fine particle size for the final product and escapes from the crusher. The particles fall down from the middle over and over again and are gradually pulverized to the desired particle size. However,
When powder particles that have not reached the final particle size fall from the middle of the separator or pulverizer, they do not necessarily fall to the center of the rotary table due to the influence of rising hot air. Therefore, the hot air rises again due to the hot air blowing action, causing a loss of opportunity for pulverization, increasing the dust concentration of the hot air gas, and increasing the pressure loss inside the pulverizer.

[Means for Solving the Problem] In the present invention, powder and granules that are subjected to the pulverizing action of the rotary table and the pulverizing rollers and whose fineness is coarser than the desired final product reach the separator. As a result of the separator classification action, when the powder is returned from the separator and falls onto the rotary table, it is prevented from flying up again due to the flow of hot air blowing up from below.
Moreover, in order to quickly return the powder to the center of the rotary table, a scattering prevention chute is provided on the pressure frame in which a plurality of crushing rollers are connected to each other, and the powder and granules returned from the separator are guided to the center of the rotary table. This is how it was done.

[Function] Inside the vertical crusher, the amount of circulation of the material to be crushed is usually several times the amount supplied, and the material to be crushed is pressed and crushed by a rotating rotary table and a plurality of crushing rollers. The hot air flows spirally from the inside of the rotary table to the outside while receiving air flow, and reaches an annular space forming a surrounding hot air blowing passage.

On the other hand, from the hot air blowing passage, the required hot air gas determined by the crusher model number or crushing capacity is sent through a certain space surrounded by two rings, an inner and an outer ring, and a plurality of plate blades arranged in parallel. Since it is blown up at a constant speed in the direction of the inclination angle of the plate-shaped blade, it rises on this hot air gas depending on the particle size of the material to be crushed, and the fine powder with relatively small particle size goes to the separator. reach Thereafter, due to the classification action of the separator, powders smaller than the desired fine particle size pass through the separator and are discharged from the pulverizer, but powders coarser than the desired fine particle size enter the separator and are directed downward. , after sliding along the separator chute, move to the shatterproof chute installed directly below the separator chute without being affected by the rising hot air gas from below, and slide down the inner surface of this shatterproof chute. and falls into the center of the rotary table. Thereafter, it is bitten by the crushing roller again and crushed in the same way as a newly supplied object to be crushed.

[Example] Fig. 1 and Fig. 2b show an embodiment of the vertical crusher according to the present invention, Fig. 1 is an overall schematic vertical cross-sectional view, and Fig. 2 is a cross-sectional view of the inside of the vertical crusher. An explanatory diagram showing how powder falls from a separator, (a) is a conventional example;
(b) shows an example in the present invention. Also, Figure 3 shows
FIG. 2 is a diagram showing a comparison of pressure loss within a crusher when the conventional example and the present invention are adopted.

In these figures, the crusher 1 is equipped with a casing 20 that houses the entire crushing section such as a rotary table 3, which will be described later. It is integrally formed with a middle casing 20b having an internal cone 20c formed in the shape of a drum-shaped cylinder with a circular cross section and a middle casing 20b, and an upper casing 20d joined to the upper end of the middle casing 20b. A reducer 2 with a motor is disposed in the center of the lower casing 20a, and a rotary table 3 formed in a disc shape is attached to the output shaft facing upward. It is driven and rotates clockwise when viewed from above in FIG. A plurality of roller boss arms 5 are disposed on the upper outer circumferential edge of the rotary table 3, each of which has a crushing roller 4 shaped like a truncated cone, which is pivoted approximately horizontally on its lower end. A pressure frame 6 having an annular shape is fixed to the upper surface of the upper inner peripheral end by means of bolt tightening or the like, and the plurality of crushing rollers 4, roller boss arms 5, and pressure frame 6 are integrated. It is mounted on the upper surface of the rotary table 3. on the other hand,
The upper outer peripheral end of each roller boss 5 is rotatably connected to a connecting rod 8 by a pin 7 and a fork end 7a.
It is connected to a hydraulic cylinder 10 via a turnbuckle 9 and a cylinder rod 10a, and the lower end of the hydraulic cylinder 10 is connected to a rotating pin 11 and a rotating seat 12.
is fixed to the base plate 13.
Further, each powder frame roller 4 is rotatably supported on a roller boss 5 via a roller shaft 4a, and its circumferential surface is in contact with the outer circumferential surface of the upper end of the rotary table 3, so that the rotation of the rotary table Accordingly, it is configured to be rotatable in a driven manner.

On the other hand, above the center of the rotary table 3, a raw material supply pipe 16 is vertically disposed and supported by an upper casing 20d via a final refined powder discharge pipe 22. Around the periphery, a separator 15 formed of an inverted conical cylinder is supported and fixed to the middle casing 20b by a stay (not shown), and a separator 15 is provided on the upper surface of the outer periphery of the upper end for applying a swirling force to the inflowing dust-containing gas. , movable vane 15a
are arranged evenly in the circumferential direction, and one end is connected to the bearing 1.
5c and a handle 15d.
It is rotatable and can be adjusted from the outside.

Furthermore, an annular hot air passage 21 is provided below the outer periphery of the rotary table 3 and is connected to the hot air generator through a duct 18. Above the hot air passage 21, the rotary table 3 and the casing 20 are connected
A plurality of plate-shaped blades 14c are arranged at equal intervals around the circumference while maintaining a required angle of inclination with respect to the horizontal plane. It will be permanently installed. In addition, at the bottom of the hot air passage, there is a discharge chute 19 for temporarily discharging foreign matter during crushing and surplus crushed materials in the event of overload.
is installed and can be taken out from an ejection door 19b which can be freely rotated around a rotation pin 19a as appropriate.

Further, a scattering prevention chute 17 in the shape of an inverted truncated cone is disposed at the center of the pressure frame 6 to which the plurality of roller bosses 5 are integrally fixed, and is fixedly suspended from the inner circumference of the upper surface of the pressure frame 6. The coarse powder that has slid down the inner surface of the separator chute 15g is guided to the center of the upper surface of the rotary table 3.

The operation of the crusher configured as described above will be explained using crushing of limestone as an example.

After starting the reducer 2 with a motor to rotate the rotary table 3, the material to be crushed is supplied from the supply pipe 16 to the center of the upper surface of the rotary table 3 using a conveyor such as a conveyor (not shown) while maintaining confidentiality. Then, due to the rotation of the rotary table 3 and the centrifugal force of the rotation, the object to be crushed draws a spiral trajectory and moves toward the outer periphery of the rotary table 3. rotary table 3
Since the crushing roller 4 is rotating on the outer periphery of the
Most of the moved material to be crushed is caught between the crushing roller 4 and the rotary table 3, and is crushed into fine powder by compression, impact, and shearing action. This fine powder, coarse particles and intermediate particles that are not bitten by the crushing roller 4 and come off the periphery of the rotary table 3 fall into the annular space 14, but at this time, they are sent through the duct 18 by the hot air generator. Since the hot air blows up from the hot air passage 21 into the annular space 14, these fine powders and intermediate particles rise inside the crusher together with the hot air. The fine powder and intermediate particles that have risen rise between the separator 15 and the inner cone 20c of the casing, change their course direction horizontally near the top of the upper casing 20d, and move along the set inclination of the movable vane 15a. It swirls and flows in.
In this way, the fine powder that has reached the desired fine powder particle size, which has been classified by the centrifugal classification action of the separator, is sent to the next step via the discharge pipe 22. On the other hand, coarse powder that does not reach the fine particle size slides on the inner surface of the separator and accumulates near the flap 15f whose upper end is rotatably supported on the skirt 15e fixed to the side wall of the supply pipe 16, and due to the action of gravity. While pushing this flap 15f away, it slides down the inner surface of the lower chute 15g. An anti-scattering chute 17 located above the center of the rotary table 3 and installed inside the pressure frame 6 eliminates the influence of hot air blowing up from below, and the rotary table Fall to the upper center of 3.

Figure 2 shows the situation in which the coarse powder and intermediate particles after classification fall from 15 g of separator shoot.
The particles falling from g are lifted up by the hot air, which is a steady flow, coming up from the annular space 14,
In contrast, in the method (b) of the present invention, the return to the rotary table 3, which is the original purpose, is inhibited and an extra circulation flow is generated in the crusher, causing an increase in pressure loss.
By providing the anti-scattering chute 17 directly below the separator chute 15g, it is intended to prevent particles from flying up due to hot air as much as possible, eliminate unnecessary circulating flow, and reduce pressure loss.

Based on the above idea, in order to compare the conventional method and the method according to the present invention, an experimental machine was used to
The material to be crushed is limestone, the hot gas air volume, the pressure of the crushing rollers, the table rotation speed, the roller shape, and other crushing conditions are the same, and the crushing amount and pressure loss of the crusher are determined by the presence or absence of a shatter prevention chute. As a result of experimenting with the correlation, the test results shown in FIG. 3 were obtained. According to this, although the values differ depending on the size of the amount of pulverization, in both cases, the pressure loss is lower with the anti-scattering chute than without it, and the reduction rate is about 20 to 40%. Ta.

From the above results, it was found that the method of the present invention is highly effective in reducing pressure loss.

In this embodiment, the type of separator is a fixed movable vane type centrifugal type, but a rotor type rotating type may of course be adopted. Further, the liner of the rotary table may not be a flat type, but may be of an inclined type or a plate type, and the corresponding crushing roller may be changed to a type that is compatible with these types. Further, the scattering prevention chute can have any length, and it goes without saying that it may be a branched pipe instead of a single cylinder.

In addition, in this embodiment, the crushing roller, which is driven by the rotation of the table, receives a thrust force in the circumferential direction and tries to move in the horizontal direction. It goes without saying that a rotation inhibiting means is provided to prevent these movements.

[Effects of the Invention] As is clear from the above description, according to the present invention, a scattering prevention chute is provided between the separator chute and the rotary table in the vertical crusher, thereby reducing the amount of dust from the separator. Almost all of the returned powder is not blown up by the hot air rising from below midway through the rotary table, and almost all of it can fall smoothly onto the center top surface of the rotary table, so there is no excess circulating flow, and the grinding process is improved. The pressure loss of the machine can be reduced. Therefore, running costs such as the power unit of the exhaust fan can be reduced, and the opportunity to crush the returned powder increases, improving the crushing efficiency and increasing the crushing capacity with the same model number. In addition, the concentration of dust floating between the rotary table and the separator inlet is reduced, resulting in more stable operating conditions and less vibration, achieving long-term continuous stable operation of the mill and improving operability.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic vertical cross-sectional view showing one embodiment of a vertical crusher according to the present invention, and FIG. 2 is an explanatory diagram showing how the returned powder falls from a separator in the vertical crusher. (a) shows a conventional example, and (b) shows an example according to the present invention. FIG. 3 is a comparison diagram between a conventional example and an example of the present invention, showing the correlation between the pressure loss inside the crusher and the crushing capacity. 1... Vertical crusher, 3... Rotating table, 4...
... Grinding roller, 6 ... Pressure frame, 14 ... Annular space, 15g ... Separator chute, 17 ... Scattering prevention chute.

Claims (1)

[Claims] 1. It has a rotary table and a plurality of crushing rollers arranged on the rotary table, and is equipped with a pressure frame that connects the plurality of crushing rollers to each other, and has a pressure frame on the top that allows the crushing by the rotary table and the crushing rollers. In a vertical crusher equipped with a separator that classifies the crushed material into coarse powder and fine powder and drops the coarse powder toward the rotary table, the coarse powder classified by the separator is dropped onto the rotary table. A vertical crusher characterized in that a guiding scattering prevention chute is located below the separator and fixed to the pressure frame.