JPH0326105B2 - - 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 to rotate at low speed in the lower part of a cylindrical casing, and a part that divides the outer circumference of the upper surface into equal parts 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.

In this vertical crusher, powder as a raw material is supplied to the center of the rotary table through a supply pipe, and when the table rotates, the powder is subjected to centrifugal force in the radial direction of the table, and as it slides on the table, it is rotated by the table in the direction of rotation. It receives the force, slides between it and the table, and 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 periphery of the rotary table while drawing a spiral trajectory on the table. A roller is pressed against this outer periphery and rotates, so
The spirally shaped granules enter between the roller and the rotary table from a direction forming a certain angle with the roller axis, and are bitten and pulverized.

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

By the way, it is rare for the material to be crushed supplied to the crusher to be crushed into the fine powder particle size required by this crusher by being subjected to the crushing action by the crushing rollers only once, and the material may fall to the center of the rotary table. Not all of the crushed material is bitten by the crushing rollers, so even if the powder and granules that reach the outer peripheral edge of the rotary table rise up on the hot air current blowing up from the annular space, they will not be able to be crushed by the crusher. By the time the particles reach the separator installed at the top, depending on their particle size, they may fall or be classified and removed by the separator and returned to the rotary table.

In this way, the pulverized material that is constantly fed into the pulverizer rises from the rotary table to the separator, or rises from the rotary table until it reaches the desired fine particle size and flows out of the pulverizer. The particles fall from the middle of the separator over and over again until they are gradually pulverized to a desired particle size.

[Problems to be Solved by the Invention] As described above, the particles that are carried by the hot air current rising inside the casing and flow into the separator are classified into coarse particles and fine particles by the classification action of the separator. be done. In this case, it would be ideal if the coarse particles with a particle size larger than the predetermined particle size would fall from the bottom of the separator toward the table surface, and only the fine particles would be extracted from the casing through the outlet, but in reality, This kind of ideal classification is not achieved, and some of the coarse particles are drawn out of the casing through the discharge port, while some of the fine particles are also returned to the table surface, resulting in product degradation. Problems arise such as coarse particle size, decreased pulverization efficiency due to over-pulverization, and increased pressure loss (including increased fan power consumption) due to increased circulation of fine particles.

[Means for Solving the Problems] The present invention provides a casing having a discharge port for fine powder transported by air flow in the top surface (casing top plate);
A separator provided at an upper part within the casing, a rotary table disposed within the casing, and a plurality of crushing rollers disposed on the rotary table, the separator being disposed at the same time as the discharge port. In a vertical crusher that is equipped with a cylindrical hood, an airflow inlet provided around the upper part of the hood, and a vane for swirling the airflow provided in the inlet, A substantially umbrella-shaped airflow guide member is provided coaxially with the exhaust port in a portion on the inner circumferential side of the vane, and an airflow passage communicating with the exhaust port is formed between the top surface of the casing and the airflow guide member. This vertical crusher is characterized in that the distance between the top surface of the casing and the airflow guide member becomes smaller as it approaches the discharge port.

[Function] In the present invention, a substantially umbrella-shaped airflow guide member is provided in the separator, and the airflow introduced into the casing with swirling force applied by the vane is directed between the separator top plate and the guide member. It reaches the outlet while swirling between the two, and flows out of the casing. Therefore, the distance between the guide member and the casing top plate portion becomes gradually smaller toward the outlet side, and the swirling flow velocity increases toward the outlet side compared to the case without the airflow guide member. This makes it possible to perform so-called sharp classification with narrower classification points than in the case without the airflow guide member, and the above-mentioned problems are solved.

[Example] FIG. 1 is an overall schematic vertical sectional view showing an example of a vertical crusher according to the present invention.

In FIG. 1, 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. 20a, and an internal cone 2 with a circular cross section that is drawn in the middle.
It is provided with a middle casing 20b in which a casing 0c is installed, 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 arranged at the upper outer peripheral end of the rotary table 3, and each of the roller boss arms 5 has a truncated conical crushing roller 4 pivotally attached to its lower end, which is pivoted in a substantially horizontal state. There is.

A pressure frame 6 having an annular shape (an annular shape in this embodiment) is fixed to the upper surface of the upper inner peripheral end of the roller boss arm 5 by means such as bolt tightening, and a plurality of crushing rollers 4 and rollers are attached to the pressure frame 6. The boss arm 5 and the pressure frame 6 are integrally formed and 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 connected to a pin 7 and a fork end 7.
The connecting rod 8 and turnbuckle 9 are rotatably connected by a.
The lower end of the hydraulic cylinder 10 is connected to a base plate 13 through a rotating pin 11 and a rotating seat 12.

Each crushing roller 4 is rotatably supported on a roller boss 5 via a roller shaft 4a, and its peripheral surface is in contact with the outer peripheral surface of the upper end of the rotary table 3, so that it is driven as the rotary table rotates. It is rotatable.

On the other hand, a discharge port 22a is provided above the center of the rotary table 3, and a final fine powder discharge pipe 2 is provided.
2 are connected. Further, the raw material supply pipe 16 is inserted from above the casing through the ceiling wall of the discharge pipe 22 into the discharge port 22a, and is arranged so that its lower end reaches near the lower part of the separator 15. This raw material supply pipe 16 is supported by the upper casing 20d via a discharge pipe 22, and around this raw material supply pipe 16, a separator 15 formed of an inverted conical cylinder is connected to the middle casing 20b by a stay (not shown). is supported by On the outer circumferential upper surface of the upper end of this separator 15,
A plurality of movable vanes 15a for imparting swirling force to the incoming dust gas are arranged evenly in the circumferential direction, and can be freely rotated and adjusted from the outside by a shaft 15b whose one end is supported by a bearing 15c and a handle 15d. It's summery.

An airflow guide member 22c having a substantially umbrella shape (cone shape in this embodiment) is provided coaxially with the discharge port 22a between the discharge port 22a and the vane 15a. This airflow guide member 22c is connected to the raw material supply pipe 16. A gas passage 22b is formed between the casing top plate portion and this airflow guide member, and communicates with the discharge port 22a. The closer the airflow guide member 22c is to the outlet 22a, the closer the airflow guide member 22c is to the casing top plate, and the closer the expected passage 22b is to the outlet 22a, the smaller the height is.

On the other hand, an annular hot air passage 21 is provided below the outer periphery of the rotary table 3 and is connected to a hot air generator through a duct 18.
Above the rotary table 3 and the casing 20
An annular space 14 is defined between the inner circumferential wall 14a and the outer circumferential wall 14b. In this annular space 14, a plurality of plate-shaped blades 14c are arranged and fixed at equal intervals around the circumference while maintaining a required inclination angle with respect to the horizontal plane.

In addition, a discharge chute 19 is installed at the bottom of the hot air passageway to temporarily discharge foreign matter during crushing and surplus materials to be crushed in the event of overload, and a discharge door 19b that is rotatable around a rotating pin 19a. The structure allows for easier removal.

The operation of the crusher configured as above will be explained next.

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 while maintaining airtightness by a conveyor such as a conveyor (not shown). 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, the hot air generator sends them through the duct 18. 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 down 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. While pushing this flap 15f away by the action of gravity, it slides down the inner surface of the lower chute 15g and falls onto the upper surface of the rotary table 3.

Therefore, in the present invention, the cone-shaped guide member 22
c, and the passage 22b is configured so that the height becomes smaller as it approaches the discharge port 22a.
Classification becomes sharp.

The reason for this will be explained below with reference to FIG.

FIG. 3 is a plan view for explaining the operation of the centrifugal separator employed in the present invention.

In this centrifugal separator, a swirling force is applied to the airflow by the vanes 15a, and the airflow forms a spiral as shown by arrow Y and flows to the discharge port 20a. Particles are transported in this airflow, and the particles P are affected by the radial component a of the transport force received from the swirling flow Y and the circumferential component vcosθ of the particle flow velocity v in the swirling direction. The centrifugal force caused by this is applied.

Then, the coarse particles to which a centrifugal force greater than the force a is applied are pushed outward and separated, and the force a
Small particles to which a smaller centrifugal force is applied are carried by airflow and flow toward the center.

By the way, in general, in a swirling flow, the closer the flow is to the center, the closer the flow is in the radial direction, and the radial component a of the transport force that particles receive from the swirling flow also becomes larger.

Therefore, in the conventional separator shown in Fig. 2, when coarse particles that are not separated in the outer part due to various reasons enter the inside of the swirling flow,
It became increasingly difficult to separate the particles, and particles with large diameters were easily mixed with the product and flowed out from the internal outlet without being separated.

On the other hand, in the separator employed in the present invention, the air flow passage becomes narrower as it approaches the discharge port 22a, and therefore, the flow velocity of the air flow increases as it approaches the inside of the swirling flow. This also increases the centrifugal force applied to the particles in the radial direction a.
When the centrifugal force b and the centrifugal force b are balanced, the particles are classified sharply with a predetermined particle size as the boundary.

Note that FIG. 2 is a diagram showing a separator configuration of a vertical crusher corresponding to a conventional example without the above-mentioned air flow guide member, and a short tube 22d is provided hanging from the opening edge of the discharge 22a. The rest of the configuration is the same as in FIG. 1.

4 and 5 are explanatory diagrams of a separator structure of a crusher showing other embodiments of the present invention. Fourth
The figure shows a guide member 22f that is gently sloped on the center side (the center side may be horizontal) and steeply sloped on the outer circumferential side, and FIG. 5 shows a guide member 22 that is curved.
It is a crusher equipped with g.

The separator of the crusher shown in FIGS. 4 and 5 similarly performs sharp classification.

FIG. 6 shows the average particle size ratio when limestone is pulverized with various guide vane angles; fine pulverization is possible by appropriately selecting the vane angle.

In the present invention, the liner of the rotary table may not be of the flat type, but may be of the inclined or plate type, and the corresponding crushing roller may be changed to a type that is compatible with these types.

[Effects of the Invention] As is clear from the above explanation, the pulverizer of the present invention is equipped with a separator that efficiently classifies the pulverized material, and improves product precision, pulverization efficiency, and reduces fan power cost. Effects such as reduction can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic sectional view showing an embodiment of a vertical crusher according to the present invention, FIG. 2 is a sectional view showing a conventional example, FIG. FIG. 5 is a sectional view showing a different embodiment.
FIG. 6 is a graph showing partial classification efficiency and average particle size ratio. 1... Vertical crusher, 3... Rotating table, 4...
...Crushing roller, 6...Pressure frame, 14...Annular space, 15g...Separator chute, 22a...
Exhaust port, 22b... Airflow passage, 22c, 22f,
22g...Guide member.

Claims (1)

[Claims] 1. A casing having a discharge port for fine powder transported by airflow on the top surface, a separator provided at the upper part of the casing, a rotary table installed in the casing, and a plurality of pulverizers placed on the rotary table. and a roller, the separator comprising:
a cylindrical hood provided coaxially with the discharge port;
In a vertical crusher that is equipped with an airflow inlet provided around the upper part of the hood and a vane for swirling the airflow provided in the inlet, the inner peripheral side of the vane in the separator A substantially umbrella-shaped airflow guide member is provided coaxially with the exhaust port, and the space between the top surface of the casing and the airflow guide member is defined as an airflow passage communicating with the exhaust port, and the closer to the exhaust port the casing top becomes. A vertical crusher characterized by reducing the distance between the face part and the airflow guide member.