JP3101786B2 - Collision type air crusher - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impingement type airflow pulverizer for pulverizing powdery raw materials using a jet airflow (high-pressure gas).

[0002]

2. Description of the Related Art In a collision type air flow pulverizer using a jet air flow, a powder material is put on a jet air flow to form a particle mixed air flow.
Injection is performed from the outlet of the accelerating tube, and this particle mixed gas stream is caused to collide with a collision surface of a collision member provided in front of the outlet of the accelerating tube, and the powder material is pulverized by the impact force.

The details will be described below with reference to a conventional collision type air flow pulverizer shown in FIG.

In the conventional collision type airflow pulverizer, a collision member 4 is provided opposite to an outlet 13 of an acceleration tube 3 to which a high pressure gas supply nozzle 2 is connected, and the acceleration tube is supplied by the flow of the high pressure gas supplied to the acceleration tube 3. The powder raw material is sucked into the acceleration tube 3 from the powder raw material supply port 1 which is communicated in the middle of the pipe 3, and is injected together with a high-pressure gas to collide with the collision surface of the collision member 4 and to be pulverized by the impact. It is what we did.

[0005]

Conventionally, as shown in FIGS. 8 and 9, the collision surface 14 of the collision member in such a crusher is in a jet stream direction (axial direction of the accelerating tube) on which the powder material is loaded. On the other hand, a planar shape which is vertical or inclined (for example, 45 °) has been used (Japanese Patent Laid-Open No. 57-5055).
4 and JP-A-58-143853).

[0008] In the pulverizer shown in FIG. 8, the powdery raw material having a coarse particle diameter is supplied from an inlet 1 to an acceleration tube 3, and the powdery raw material collides with a collision member 4 by a jet stream blown out from a jet nozzle 2. It is beaten to the surface 14, crushed by the impact force, and discharged from the discharge port 5 to the outside of the crushing chamber. However, when the collision surface 14 is perpendicular to the axial direction of the acceleration tube 3, the ratio of the raw material powder blown out from the jet nozzle 2 and the powder reflected on the collision surface 14 coexist near the collision surface 14 is high. Therefore, the powder concentration in the vicinity of the collision surface 14 becomes high, so that the pulverization efficiency is not good. further,
The primary collision at the collision surface 14 is the main
It cannot be said that the secondary collision with the system is being used effectively. Furthermore, in a crusher in which the angle of the collision surface is perpendicular to the acceleration tube 3,
When the thermoplastic resin is pulverized, fusion and agglomerates are apt to be generated due to local heat generation at the time of collision, which makes stable operation of the apparatus difficult and causes reduction in pulverization ability. For this reason, it has been difficult to increase the powder concentration for use.

In the crusher shown in FIG. 9, since the collision surface 14 is inclined with respect to the axial direction of the acceleration tube 3, the collision surface 14
The powder concentration in the vicinity is lower than that of the pulverizer of FIG. 8, but the pulverization pressure is dispersed and lower. Furthermore, it cannot be said that the secondary collision with the crushing chamber wall 6 is effectively used.

As shown in FIG. 9, when the collision surface 14 has an angle of 45 ° with respect to the accelerating tube, the above-mentioned problems are lessened when the thermoplastic resin is pulverized. However,
Since the impact force used for the crushing during the collision is small and the crushing due to the secondary collision with the crushing chamber wall 6 is small, the crushing ability is 1/2 to 1 / 1.5 as compared with the crusher of FIG. The crushing ability drops.

[0009] Japanese Patent Laid-Open Publication No. 1-148740 and Japanese Patent Laid-Open Publication No. 1-2 have disclosed a collision-type airflow pulverizer in which the above problems have been solved.
No. 54266 has been proposed. In the former case, FIG.
As shown in (1), the raw material collision surface 14 of the collision member is disposed at right angles to the axis of the acceleration tube, and the conical projection 15 is provided on the raw material collision surface to prevent the reflected flow at the collision surface. It has been proposed.

In the latter, as shown in FIG. 10, the tip portion of the collision surface of the collision member has a specific conical shape, so that the powder concentration in the vicinity of the collision surface is reduced, and the collision with the crushing chamber wall 6 is efficiently performed. 2. Description of the Related Art A collision type air pulverizer designed to cause secondary collision has been proposed.

With the above-mentioned structure, the conventional problems are considerably improved, but are still not sufficient. Further, as a recent need, a finer pulverized product has been desired. A good pulverizer is expected.

An object of the present invention is to provide an impingement type air current pulverizer which can solve the above-mentioned problems of the prior art and can pulverize powder raw materials efficiently.

[0013]

The above objects are achieved by the present invention described below.

That is, the present invention relates to a collision type air current pulverizer having an accelerating tube for transporting and accelerating an object to be crushed by a high-pressure gas and a crushing chamber for finely crushing the object to be crushed. A collision member having a collision surface provided to face an opening surface of an outlet of the acceleration tube, and having a collision surface on the collision surface for crushing an object to be ground at least three times by collision. The crushing chamber has a side wall for further crushing the crushed material crushed on the collision surface by collision.

[0015] Further, the present invention provides the above crusher,
The collision surface of the collision member has a protruding center portion that protrudes,
An outer peripheral collision surface for further crushing the primary crushed material crushed at the projecting central portion by collision is provided in multiple stages around the projecting central portion, and the apex angle of the projecting central portion is α ₁ (° )
And the apex angle on the extension of the outer peripheral collision surface is α ₂ , α ₃
.., Α _n (°) (n ≧ 3), and α ₁ , α ₂ , α ₃ .
α _n is represented by the following equation α ₁ <α ₂ <α ₃ ... <α _n , 0 ° <α ₁ <90 °, 90
This is an impingement airflow pulverizer that satisfies ° <α _n <180 °.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on embodiments.

FIG. 1 is a schematic sectional view of an embodiment of the present invention and a flow chart of a pulverizing apparatus in which a pulverizing step using the pulverizer and a classification step using a classifier are combined.

The powder material 7 to be pulverized is supplied to the acceleration tube 3 from the powder material supply port 1 above the acceleration tube 3.
A compressed gas such as compressed air is introduced into the acceleration tube 3 from the compressed gas supply nozzle 2, and the powder material 7 supplied to the acceleration tube 3 is instantaneously accelerated to have a high speed. The powdery raw material 7 discharged from the acceleration tube outlet 13 into the pulverizing chamber 8 at a high speed collides with the collision surface 14 of the collision member 4 and is pulverized. In the crusher shown in FIG.
Is an outer peripheral collision surface 1 for further crushing, by collision, a protruding central portion 141 having a conical shape and a primary crushed material crushed at the protruding central portion around the protruding central portion.
42, 143. The pulverizing chamber 8 has a side wall 6 for pulverizing the pulverized material pulverized on the outer collision surface 143 by collision.

FIG. 2 is a cross-sectional plan view of FIG. 1 and will be described in more detail.

As described above, by providing the conical projection having a central portion projecting on the raw material collision surface, the solid-gas mixed flow of the pulverized raw material and compressed air ejected from the accelerating tube is formed by the projection 14.
After the first crushing is performed on the surface of No. 1 and the second crushing is performed on the outer circumferential collision surface 142, the crushed material is tertiary crushed on the outer circumferential collision surface 143.
Thereafter, the material is further pulverized on the side wall 6 of the pulverizing chamber.

At this time, the apex angle α ₁ (°) of the central portion of the collision member projecting from the collision surface and the outer collision surfaces 142 and 1
The vertical angles α ₂ (°) and α ₃ (°) on the extension of 43 are α ₁ <α ₂ <α ₃ , 0 ° <α ₁ <90 °, 90 ° <
When α ₃ <180 ° is satisfied, grinding is performed very efficiently.

When α ₁ ≧ 90 °, the reflected flow of the primary pulverized material on the projection surface disturbs the flow of the solid-gas mixed flow ejected from the acceleration tube, and efficiently collides with the outer peripheral collision surface. Is not done. Further, when α ₃ = 180 °, that is, when the outer peripheral collision surface 16 is perpendicular to the solid-gas mixed flow, the reflected flow at the outer peripheral collision surface flows toward the solid-gas mixed flow,
Undesirably, turbulence of the gas-solid mixed flow occurs. In addition, when the powder concentration on the outer peripheral collision surface is increased and a powder of a thermoplastic resin or a powder mainly containing a thermoplastic resin is used as a raw material,
Fused materials and aggregates are likely to be generated on the outer peripheral collision surface. If such a fusion occurs, stable operation of the apparatus becomes difficult. On the other hand, when α ₃ ≦ 90 °, the impact force of the pulverization on the projection surface and the outer peripheral collision surface is weakened, so that the pulverization efficiency is lowered, which is not preferable.

As described above, α ₁ , α ₂ , and α ₃ satisfy α ₁ <α ₂ <α ₃ , 0 ° <α ₁ <90 °, 90 ° <
When α ₃ <180 ° is satisfied, as shown in FIG. 2, the pulverization is efficiently performed in multiple stages, and the pulverization efficiency can be improved. In addition,
In FIG. 1, the embodiment in the case of n = 3 has been described. However, the present invention is not limited to this, and it is sufficient that n ≧ 3 is satisfied.

It is a feature of the present invention to increase the number of collisions and make the collision more effective as compared with a conventional pulverizer.
It is possible to improve the pulverization efficiency, to prevent generation of a fused material at the time of pulverization, and to perform a stable operation.

FIG. 3 is a schematic sectional view of another preferred embodiment of the present invention, and is a flowchart of a pulverizing apparatus in which a pulverizing step using the pulverizer and a classifying step using a classifier are combined, and FIG. 5 is an enlarged sectional view taken along line AA of FIG.
FIG. 4 is a sectional view taken along line BB in FIG. 3.

The pulverizer shown in FIG. 3 will be described. An accelerating tube 21 for transporting and accelerating an object to be pulverized by a high-pressure gas,
A collision member 30 having a collision surface provided opposite to the acceleration tube outlet, wherein the acceleration tube 21 has a Laval nozzle shape, and a high-pressure gas ejection nozzle 23 is provided upstream of a throat portion of the acceleration tube 21;
Is provided between the outer wall of the high-pressure gas ejection nozzle 23 and the inner wall of the throat portion 22, and further, an axial cross-sectional shape of a grinding chamber 34 provided to be connected to the outlet of the acceleration tube 21. Has a circular shape.

The material to be crushed supplied from the crushed material supply cylinder 25 is formed such that the inner wall and the center of the acceleration tube throat portion 22 of the acceleration tube 21 having a Laval nozzle shape whose central axis is disposed in the vertical direction are the center of the acceleration tube 21. The material reaches a pulverized material supply port 24 formed between the shaft and the outer wall of the high-pressure gas ejection nozzle 23. On the other hand, the high-pressure gas is introduced from the high-pressure gas supply port 26, passes through the high-pressure gas chamber 27, and passes through one or preferably a plurality of high-pressure gas introduction pipes 28.
3 and spouts while rapidly expanding in the direction of the acceleration tube outlet 29. At this time, due to the ejector effect generated in the vicinity of the accelerating tube throat portion 22, the material to be ground is sucked from the material to be ground supply port 24 toward the acceleration tube outlet 29 while being accompanied by the gas coexisting therewith. In the accelerating tube throat portion 22, the fuel is rapidly accelerated while being uniformly mixed with the high-pressure airflow, and is uniformly distributed on the collision surface of the collision member 30 disposed opposite the accelerating tube outlet 29 in a state of a uniform solid-gas mixed airflow without unevenness in dust concentration. collide.

Since the impact force generated at the time of collision is given to the individual particles (objects to be crushed) which are sufficiently dispersed, very efficient crushing can be performed. The pulverized material pulverized on the collision surface of the collision member 30 further repeats collision between the pulverizing chamber side wall 32 and the surface of the collision member 30 to further increase the pulverization efficiency, and the pulverized material disposed behind the collision member 30 It is discharged from the discharge port 33.

The collision surface of the collision member has a protruding central portion 141 and an outer periphery around the protruding central portion for further crushing the primary pulverized material pulverized at the protruding central portion by collision. It has collision surfaces 142 and 143. The pulverizing chamber 34 has a side wall 32 for pulverizing the pulverized material pulverized on the outer peripheral collision surface 143 by collision.

As in the case of the pulverizer shown in FIG. 1, the object to be pulverized is primarily pulverized on the surface of the projection on the collision surface.
After the secondary pulverization in step 2, the secondary pulverization is performed in the outer peripheral collision surface 143. Thereafter, the powder is further pulverized by the pulverizing chamber side wall 32.

In the pulverizer shown in FIG. 3, the center axis of the accelerating tube is disposed in a vertical direction. By setting the supply directions of the powders to be the same, it is possible to disperse the material to be ground in a high-pressure airflow that is jetted out uniformly so that there is no deviation due to the dust concentration.

Here, in order to improve the flow state of the material to be crushed, the acceleration tube shown in FIG. It is preferable that, in order to more evenly distribute the crushed object in the crushed object supply port around the long axis of the acceleration tube, the inclination in the long axis direction of the acceleration tube is 0 to 0 with respect to the vertical line. It is more preferable that the angle is within the range of 20 °, and it is even more preferable that the angle is within the range of 0 to 5 °.

Another embodiment of the present invention is shown in FIGS.
FIG. 7 is a cross-sectional view taken along line CC of FIG. FIG.
Are the supply port 24 for the pulverized material, the Laval nozzle 3
5 is the same as that shown in FIG. 3 except that the acceleration tube throat portion 36 is different.

The pulverizers of FIGS. 3 and 6 differ from the pulverizer of FIG.
The powder raw material in the acceleration tube can be more uniformly dispersed, and therefore, the pulverization efficiency can be further improved.

The crusher shown in FIGS. 3 and 6 also
α ₁ , α ₂ , α ₃ are α ₁ <α ₂ <α ₃ , 0 ° <α ₁ <90 °, 90 ° <
When α ₃ <180 ° is satisfied, the pulverization is performed efficiently, and the pulverization efficiency can be improved.

FIGS. 3 and 6 show an embodiment in which n = 3, but the present invention is not limited to this, and it is sufficient that n ≧ 3.

In the pulverizer of the present invention, it is preferable that the inner diameter of the outlet of the accelerating tube has an inner diameter smaller than the diameter b of the collision member. It is preferable that the tip of the projecting center portion projecting from the collision surface of the collision member and the central axis of the accelerating tube be substantially coincident with each other in terms of uniform pulverization. The distance a between the accelerator tube outlet and the end of the collision surface of the collision member is 0.1 mm of the diameter of the collision member.
It is preferably from 2 to 2 times, more preferably from 0.2 to 1.0 times.

If it is less than 0.1 times, the dust concentration near the collision surface increases, and if it exceeds 2 times, the impact force is weakened and the pulverizing efficiency tends to decrease.

The shortest distance c between the end of the collision surface of the collision member and the side wall (inner wall) of the crushing chamber is 0.
It is preferably 1 to 2 times or less. If the pressure is less than 0.1 times, the pressure loss at the time of passage of the high-pressure gas is large, not only lowering the pulverization efficiency, but also the flow of the pulverized material tends not to be smooth. In this case, the effect of the collision of the objects to be crushed is reduced, and the crushing efficiency is reduced. The shape of the crushing chamber is not particularly limited as long as the distance between the end of the collision surface of the colliding member and the side wall of the crushing chamber satisfies the above value.

The pulverizer of the present invention is generally suitable for finely pulverizing solid particles which are liable to be fused or agglomerated. Specifically, the pulverizer may be used to roughly prepare an electrophotographic toner composition using a thermoplastic resin. Effective for atomization of particles.

Hereinafter, an example of the production of toner by the pulverizer of the present invention will be described.

(Production Example of Toner) Styrene-butyl acrylate-divinylbenzene copolymer 100 parts by weight (monomer polymerization weight ratio 80.0 / 19.0 / 1.0, weight average molecular weight (Mw) 350,000) (Average particle diameter 0.18 μm) 100 parts by weight Low molecular weight ethylene-propylene copolymer 4 parts by weight Positive charge control agent 2 parts by weight Toner raw material composed of the mixture of the above formulation is mixed with a biaxial extruder PCM-30 (Ikegai Iron Works) Melt kneading). After cooling, a coarsely pulverized product of 0.1 to 1 mm was obtained with a hammer mill.

The obtained coarsely pulverized product was subjected to an air flow classifier and a fine pulverizer (α ₁ = 40 °, α ₂ at the collision surface of the collision member) shown in FIG.
= 120 °, α ₃ = 160 °) and compressed air of 6.0 Nm ^{3 /} min (6.0 kgf / cm ² ) from the compressed gas supply nozzle to the pulverizer. To obtain a finely pulverized product having a weight average particle size of 8.
0 μm (measurement by Coulter counter, the same applies hereinafter)
Was finely pulverized. In the accelerating tube of the pulverizer, the inclination of the accelerating tube in the major axis direction was almost 0 ° with respect to the vertical line.

At this time, the processing amount of the fine pulverization (= the processing amount of the coarse pulverized product) was 41 kg / hr. Further, even after the continuous operation for 6 hours, no fused product was generated.

The particle size distribution of the finely pulverized product or the toner can be measured by various methods. In the present invention, the measurement was performed using a Coulter counter. That is, a Coulter Counter TA-II type (manufactured by Coulter) was used as a measuring device, and an interface (manufactured by Nikkaki) for outputting a number distribution and a volume distribution was connected to a CX-1 personal computer (manufactured by Canon). Prepares a 1% NaCl aqueous solution using primary sodium chloride. As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and the measurement sample is further diluted with 2 to 50 ml.
Add 20 mg. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the above-mentioned Coulter Counter TA-II was used to form an aperture of 100 μm.
Using an aperture, the particle size distribution of the particles of 2 to 40 μm was measured on the basis of the number, and the value of the weight average particle size according to the present invention was obtained from the measured values.

The obtained finely pulverized product is further classified by using a dispersion separator (manufactured by Nippon Pneumatic Industries, Ltd.) to remove fine powder having a specified particle size or more, thereby obtaining a classified product prepared in good yield. Was excellent for toner.

In addition, fine pulverization was also attempted for other fine powder production apparatuses or Production Examples 2 to 4 in which the shape of the collision surface was changed, and for comparison, the case where the collision surface was a flat surface or a cone.

The results are shown in the following table.

[0049]

[Table 1]

[0050]

As described above, according to the present invention, the solid-gas mixed flow injected from the accelerating tube is primarily pulverized at the conical protruding center provided on the collision member, and is further pulverized at the protruding center. After being pulverized in multiple stages at the peripheral collision surface provided around the pulverizer, the pulverization is further pulverized on the side wall of the pulverization chamber. Therefore, the pulverization efficiency is greatly improved as compared with a conventional collision type airflow pulverizer. Further, the reflected flow after the collision does not flow toward the accelerating tube, and therefore, the turbulence of the solid-gas mixed flow can be prevented, and the generation of the fused material on the collision surface can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a collision type air current pulverizer embodying the present invention.

FIG. 2 is a cross-sectional plan view of FIG.

FIG. 3 is a schematic sectional view of another collision-type airflow pulverizer embodying the present invention.

FIG. 4 is an enlarged sectional view taken along line AA of FIG. 3;

FIG. 5 is an enlarged sectional view taken along line BB of FIG. 3;

FIG. 6 is a schematic sectional view of another collision-type airflow pulverizer embodying the present invention.

FIG. 7 is an enlarged sectional view taken along line CC of FIG. 6;

FIG. 8 is a schematic sectional view showing a conventional crusher.

FIG. 9 is a schematic sectional view showing a conventional crusher.

FIG. 10 is a schematic sectional view showing a conventional crusher.

FIG. 11 is a schematic sectional view showing a conventional crusher.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Powder raw material inlet 2 Compressed gas supply nozzle 3 Acceleration tube 4 Collision member 5 Discharge port 6 Pulverization chamber side wall 7 Powder raw material 8 Pulverization chamber 13 Acceleration pipe outlet 14 Collision surface 141 Projection center part 142,143 Outer collision surface 21 Acceleration Tube 22 accelerating tube throat part 23 high-pressure gas ejection nozzle 24 pulverized material supply port 25 pulverized material supply cylinder 26 high-pressure gas supply port 27 high-pressure gas chamber 28 high-pressure gas introduction pipe 29 accelerating pipe outlet 30 collision member 32 pulverizing chamber side wall 33 pulverization Material discharge port 34 Grinding chamber 35 Laval nozzle 36 Acceleration tube throat 37 Acceleration tube outlet

────────────────────────────────────────────────── (5) References JP-A-4-322275 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) B02C 19/00 B02C 19/06

Claims (2)

(57) [Claims] 1. A collision type air current pulverizer having an accelerating tube for conveying and accelerating an object to be pulverized by a high-pressure gas and a pulverizing chamber for pulverizing the object to be pulverized, wherein the accelerating tube is provided in the pulverizing chamber. A collision member having a collision surface provided opposite to the opening surface of the outlet, and having a collision surface for crushing the object to be crushed at least three times on the collision surface; A collision-type airflow pulverizer characterized in that the chamber has a side wall for further pulverizing the pulverized material pulverized at the collision surface by collision. 2. The collision surface of the collision member has a projecting central portion, and an outer peripheral collision surface for further crushing the primary crushed material crushed at the projecting central portion by collision. .. Α _n (°) (n). The apex angle of the protruding center portion is α ₁ (°), and the apex angles on the extension of the outer peripheral collision surface are α ₁ , α ₃ . ≧ 3), the α
₁ , α ₂ , α ₃ ... Α _n are represented by the following formulas α ₁ <α ₂ <α ₃ ... <Α _n , 0 ° <α ₁ <90 °, 90
° <alpha _n collision type air pulverizer according to claim 1, characterized by satisfying the <180 °.