JPH0257989B2 - - Google Patents

Description

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

[Prior art]

2. Description of the Related Art Vertical crushers equipped with a rotary table and rollers are widely used as a type of crusher for finely crushing granules such as cement raw materials, coal, and chemicals into powder. 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. The granules as raw materials supplied to the center of the rotary table through the supply pipe are subjected to centrifugal force in the radial direction of the table due to the rotation of the table, and as they slide on the table, they receive a force in the rotational direction from the table. The table rotates somewhat slower than the table rotation speed. The above two forces, ie, the radial and rotational forces, are combined, and the powder moves to the outer periphery of the rotary table while drawing a spiral trajectory on the table. Since a roller is pressed into contact with this outer periphery and rotates, 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 and crushed. Ru. 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.

Conventionally, the structure within the annular space for blowing up hot air from the annular space is a swirling type in which the hot air is blown up while swirling in a tornado shape, and a structure in which the hot air is blown up in a conical shape toward the upper center. A conical shape is used.

Fig. 7 is a schematic vertical cross-sectional view of a vertical crusher that adopts a rotating hot air blowing structure, and Fig. 8 is a cross-sectional view along AA of Fig. 7. An annular space 3 is formed between the casing 1 and a rotary table 2 rotating within the lower part of the casing 1, and a plurality of blades 4 move the annular space 3 at equal intervals within the annular space 3. It is arranged to block it. Each blade 4 is inclined in a direction in which the upper end is in front with respect to the rotational direction of the rotary table 2, and the blade angle β, which is this inclination angle, ranges from 30° to 70° depending on the particle size of the material to be crushed. selected between.

With this configuration, when the rotary table 2 rotates and hot air blows up in the annular space 3, the blades 4 are slanted.
The hot air that has passed through the blades 4 raises the crushed material while swirling as shown by arrow B in FIG.

Next, Figure 9 is a schematic vertical cross-sectional view of a vertical crusher that adopts a conical hot air blowing structure, and Figure 10 is the same as in Figure 9.
This is a CC sectional view, and to explain this based on the same figure, in the annular space 7 formed between the cylindrical casing 5 and the rotary table 6 that rotates within the lower part of the casing 5, there are A plurality of blades 8 are arranged to block the annular space 7 at equal intervals. In this case, each blade 8 has a blade angle β of 90° and stands upright, and an annular armor ring 9 is provided above the blade 8.

With this configuration, the hot air blowing up vertically between adjacent blades 8,
It rises while being sandwiched between two cones, an inner and outer cone, as shown by arrow D in FIG. 9, and lifts the pulverized material. Inside this cone there is no wind.

[Problem that the invention seeks to solve]

However, the following problems remain in such conventional swirling and conical hot air blowing structures. That is, first of all, the rotating type has the advantage that the residence time of the hot air above the rotary table 2 is long and drying is performed well by heat exchange between the raw material and the hot air, but on the other hand, the streamline of the hot air does not travel in a straight line. Because of the swirling flow, vent pressure loss is constantly consumed, and in order to blow up the required air volume, blowing equipment with large air volume and pressure is required, which significantly increases equipment and power costs. In addition, when the hot air swirls, the coarse particles that are swirling upward are blown away by centrifugal force in the direction along the inner wall of the casing 1, so they do not fall onto the rotary table 2 and are returned to the rotary table 2, reducing the chance of re-grinding and improving the pulverization efficiency. There was a problem with the decrease in

Next, in the case of a conical type, the blown hot air is monotonically decelerated as it travels straight along the ridge lines of the two cones, the inner and outer sides, but the flow velocity decreases near the top of the cone because the cross-sectional area of passage is reduced. As a result, pressure loss increases, and large air blowing equipment is required, resulting in increased equipment costs and power costs.
In addition, since the hot air does not swirl and centrifugal force does not act on coarse particles, the return rate to the rotating table is higher than that of the rotating type, but on the other hand, the intermediate particles fly higher toward the top of the cone and are discharged. There was a problem that it was difficult to return to the rotary table.

[Means for solving problems]

In order to solve these problems, in the present invention, the plate-shaped blades arranged in parallel in the hot air blowing passage around the rotary table are arranged such that the angle between the radiation passing through the center of the crusher and the hot air flow line, that is, the blade deflection angle, is
In addition to tilting it at an angle of 20° to 50°,
It was formed into a three-dimensional shape so that the angle between the hot air streamline and the horizontal plane, that is, the rising angle, was 50° to 85°.

[Effect]

With this configuration, the hot air blown up in the blow-up passage rises along the gas flow line formed by the blade surface, and the powder and granules blown up by the hot air are reduced due to the decrease in the flow velocity of the hot air after passing through the blade. Particle gravity overcomes the hot air drag and the coarse particles fall in order, but due to the effect of the deflection angle, they fall to the center of the table, and the chance of re-pulverization is greater than in the conventional swirl type and conical type. Furthermore, since the gravitational force of fine powder particles is small, they reach the separator provided at the top of the pulverizer while being transported by hot air.

〔Example〕

1 to 3 show an embodiment of the vertical crusher according to the present invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a partial plan view near the hot air blowing passage, and FIG. FIG. 2 is a sectional view of EE in FIG. 2; In these figures,
The crusher 11 is equipped with a casing 12 that houses the entire crushing section such as a rotary table 17, which will be described later. It is integrally formed with a casing main body 14 formed into a drum-shaped cylinder with a circular cross section and joined vertically at the center, and an upper casing 15 joined to the upper end of the casing main body 14. In the center of the lower casing 13,
A speed reducer 16 with a motor is disposed, and a rotary table 17 formed in the shape of a disk is attached to its upward output shaft. It is rotating clockwise as seen. Reference numeral 18 denotes arm shafts supported horizontally at positions dividing the outer circumference of the upper end surface of the lower casing 13 into four equal parts in the circumferential direction. A conical crushing roller 20 is rotatably supported via a roller shaft 21, and each crushing roller 20 has its circumferential surface in contact with the outer circumferential surface of the upper end of the rotary table 17. Each arm 19 is drivingly connected to a fluid pressure cylinder (not shown), etc., and is swing-adjusted by the drive thereof, so that the crushing roller 20 and rotary table 17 are adjusted according to the supply particle size of the material to be crushed.
The structure is such that the gap between the two is adjusted.

On the other hand, above the center of the rotary table 17, a cylindrical raw material supply pipe 22 is connected to a duct 23.
The raw material such as limestone, which is conveyed by the conveyor 25 in the duct 23, falls through the raw material supply pipe 22 and is placed on the rotary table 17. It is configured to be supplied to

Furthermore, below the outer periphery of the rotary table 17,
An annular hot air passage 26 is provided which is connected to the hot air generator by a duct (not shown), and an annular hot air passage 26 is provided between the outer peripheral surface of the rotary table 17 and the inner peripheral surface of the casing body 14. The hot air blowing passage 27 is formed by communicating the hot air passage 26 and the inner chamber of the casing body 14 .
The inner peripheral wall 28 and the outer peripheral wall 2 of this hot air blowing passage 27
9 has a slanted cross section as shown in Figure 3, and is formed into a truncated conical shape as a whole, and the angle Ψ between the ridgeline and the horizontal plane, that is, the rising angle Ψ between the hot air flow line and the horizontal plane. is set to be between 50° and 85°. Furthermore, hot air blowing passage 2
A plurality of plate-shaped blades 30 are disposed between the inner and outer circumferential walls 28 and 29 of 7, blocking the passage 27, at equal intervals in the circumferential direction. Each blade 30 is designated F and F ₁ in FIG. 2, respectively.
It is inclined so that the angle φ between the radiation passing through the center of the crusher and the hot air streamline is 20° to 50°, and the direction of this inclination is determined by the rotation of the rotary table 17 shown as G in FIG. The outer circumferential wall 29 side is set in a leading direction with respect to the direction.

Reference numeral 31 denotes a separator integrally formed with a rotary cylinder 31a fitted concentrically with the raw material supply cylinder 22 and an inverted cone-shaped classification plate 31b fixed to the lower part thereof, and a bearing 32 at the upper end of the upper casing 15 It is rotatably supported by a shaft, and is rotationally driven by a motor 37 via a belt 35 stretched between pulleys 33 and 34 and a speed reducer 36. Reference numeral 38 denotes an exhaust port opened in the upper casing 15, and is connected to a dust collector or the like (not shown) through a duct.

The operation of the pulverizer configured as described above will be explained using pulverization of limestone as an example. After starting the reducer 16 and the motor 37 to rotate the rotary table 17 and the separator 31, the conveyor 25 transports the limestone and supplies it to the raw material supply pipe 22. This limestone is delivered to the center of the rotary table 17. , and moves toward the outer periphery of the rotary table 17 while drawing a spiral trajectory due to the rotation of the rotary table 17 and centrifugal force. Since the crushing roller 20 is rotating on the outer periphery of the rotating table 17, most of the displaced limestone is caught between the crushing roller 20 and the rotating table 17, and is crushed by compression, impact, and shearing action into fine powder. becomes. This fine powder, coarse particles and intermediate particles that have not been bitten by the crushing roller 20 and have come off the periphery of the rotary table 17 fall into the hot air blowing passage 27, but at this time, they are sent through a duct by the hot air generator. The hot air that comes from the hot air passage 26
Since the hot air blows up from the hot air to the hot air blowing passage, these fine powders, intermediate particles, etc. rise inside the pulverizer along with the hot air. The fine powder and intermediate particles that have risen are removed by the separator 31.
The fine powder collides with the classification plate 31b and is classified, and after passing through the separator 31 and being discharged from the exhaust port 38, the fine powder is collected via a dust collector or the like. Further, the intermediate particles that have not passed through the separator 31 fall onto the rotary table 17 and are reduced, and the above-mentioned pulverization and classification are repeated.

The blowing up operation of the hot air and the pulverized material in such a pulverizing operation will be explained in more detail based on upward locus diagrams of the hot air and the granular material shown in FIGS. 4 to 6 as a front view, a plan view, and a perspective view, respectively. . The symbols in each figure are as follows.

R ₀ ... Radius of the inner wall 28 of the hot air blowing passage 27 R ₁ ... Radius of the outer circumferential wall 29 of the hot air blowing passage 27 R ₂ ... Radius of the center of the hot air blowing passage 27 H ₁ ... Hot air blowing passage 27 Height H ₂ from the lower end to the upper end of the casing drum-shaped part...Similarly, the height Rt from the lower end of the hot air blowing passage 27 to the center of the separator 31...Radius Rc of the above height _H1 point...The above height _H2 point Radius φ...Blade deflection angle, that is, the angle between the radial line passing through the center of the crusher and the center of the blade 30, and the hot air streamline Ψ...Blade rising angle, that is, the inclination angle of both peripheral walls 28, 29 in FIG.

γ...Fluid spreading angle, that is, the angle formed by the blowing direction of hot air at both ends of the blade 30 (on one side).

φ ₁ ...Blade twist angle As is clear from the figures with the above symbols, in this device, the blade deflection angle φ is
Set the blade rise angle Ψ to 50° to 50°.
Since the angle is set at 85°, the following wind force acts on the powder particles falling from the periphery of the rotary table 17 into the hot air blowing passage 27. That is, since both peripheral walls 28 and 29 of the hot air blowing passage 27 are inclined so as to have a blade rising angle Ψ, the hot air travels straight without turning, and as shown in FIG. 4, the inner peripheral wall 28 is extended. Although the blade 30 ascends in a space surrounded by a conical surface and a conical surface which is an extension of the outer circumferential wall 29, the blade 30 is tilted so as to have a blade deflection angle φ.
The hot air guided along the blades 30 travels straight upward diagonally with a spread angle γ as shown in the plan view in FIG. 5, and the space surrounded by the hot air has a conical shape as described above. Instead, it becomes a monoplane hyperboloid as shown in Figure 6. As a result, the hot air and the powder particles blown up by the hot air move straight toward the classification plate 31a of the separator 31, and as the flow speed of the hot air that transports the particles increases, the flow speed becomes monotonous more rapidly than the initial speed. Slowed down. Therefore, the larger the powder particles rising with the hot air, the faster they are returned onto the rotary table 17, and the diameter of the incident particles that ultimately reach the separator 31 becomes smaller. In addition, the flow velocity of hot air is not increased at the top of the cone unlike in conventional cone-types.
Furthermore, since there are fewer collisions between particles and particles against walls, there is less pressure loss.

Here, the reason why the blade deflection angle φ is set to 20 to 50 degrees will be explained. When experimenting with several different airflow rates, for example, when φ=20° to 50°, φ=
Compared to the conventional conical type with a 90° angle, the return rate of the material to be crushed to the table is better, and the return condition to the roller section is extremely good, making a comprehensive judgment considering blade pressure loss and falling air volume limit. Even if φ=20°
In the present invention, φ=20° to 50° because good results were obtained when the angle was 50°. Note that by decreasing the value of φ,
If it is <20°, the blade will no longer be able to fulfill its original role.

Next, the reason why the blade rising angle Ψ is set to 50° to 85° will be explained. In experiments in which limestone was used as the object to be crushed, and the weight of the limestone and the air flow rate were varied, when Ψ was set between 50° and 85°, in all cases the object to be crushed in the air centered around Ψ≒70°. The residence time of is relatively short compared to that of Ψ=90°,
Also, the pressure loss at the blade part is Ψ＜50° and Ψ＞
It was smaller than the 85° one. In addition, even if we comprehensively consider not only the pressure drop but also the reduction rate of the material to be crushed and the critical fall air volume required to lift the material to be crushed, it will be found that Ψ = 50° and around Ψ≒70°. Since the case of 85° showed good results, in the present invention, Ψ was set to 50° to 85°. In addition, it has been experimentally confirmed that in the present invention, good results are obtained due to the synergistic effect of limiting both φ and Ψ, and that the pressure loss at the blade portion is reduced by about 10 to 20% compared to the conventional one.

Note that the values of φ and Ψ above depend on the type of pulverized raw material, the supplied particle size, the product particle size, the capacity of the pulverizer (amount of pulverization),
The optimal combination is adopted depending on the air volume of the crusher, etc. Specifically, the particle density, supplied particle diameter, separator incident particle diameter, crusher size, air volume, etc. are input into the computer, and the optimum combination is determined by performing a simulation of the particle trajectory inside the crusher using φ and Ψ as parameters. .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in the vertical crusher, the plate-shaped blades arranged in parallel in the hot air blowing passage around the rotary table are The angle is
In addition to tilting it at an angle of 20° to 50°,
The angle between the hot air streamline and the horizontal plane is 50° to 85°, and the direction of the hot air streamline is three-dimensional. The powder and granular material that rises along with the movement moves straight while being rapidly monotonically decelerated, so that the trajectory of the powder and granular material becomes ideal, and the collection rate of large particles to the rotary table and the incidence rate of fine particles to the separator are as follows. This is a significant improvement over conventional crushers with swirling or conical hot air blowing structures, and pressure loss is reduced by eliminating swirling of the hot air and powder particles and speed increase at the elevated position. In addition, it is expected that the grinding efficiency will be improved by improving the table reduction rate, and the blower equipment can be downsized.

[Brief explanation of drawings]

1 to 6 show an embodiment of the vertical crusher according to the present invention, FIG. 1 is a longitudinal sectional view thereof, FIG. 2 is a partial plan view near the hot air blowing passage, and FIG. 3 is a partial plan view of the vicinity of the hot air blowing passage. Fig. 2 is an EE sectional view, Fig. 4 is a front view of the ascending locus of hot air and powder, Fig. 5 is a plan view, Fig. 6 is a perspective view, and Fig. 7 is a conventional swirling hot air A schematic vertical cross-sectional view of a vertical crusher that adopts a blow-up structure, Figure 8 is a cross-sectional view AA of Figure 7, and Figure 9 is a schematic longitudinal cross-sectional view of a vertical crusher that uses a conventional conical hot air blow-up structure. , FIG. 10 is a CC plan view of FIG. 9. 11... Vertical crusher, 12... Casing, 1
7... Rotating table, 27... Hot air blowing passage,
28...Inner circumferential wall, 29...Outer circumferential wall, 30...Blade, φ...Angle between the ray passing through the center of the blade and the perpendicular line, Ψ...The ridge line of both the inner and outer circumferential walls of the hot air blowing passage and the horizontal plane Angle.

Claims (1)

[Claims] 1. A vertical crusher equipped with a plurality of plate-shaped blades that are arranged in parallel in an annular hot air blowing passage formed between the inner wall of the casing and the outer circumferential surface of the rotary table and that block this passage in the circumferential direction, The blades are inclined so that the angle between the radiation passing through the center of the crusher and the hot air streamline is 20° to 50°, and the rising angle between the hot air streamline and a horizontal plane is 50° to 85°. A vertical crusher characterized by being installed at an angle so that