JP3313922B2 - Crusher - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverizing apparatus, and more particularly to a pulverizing apparatus for toner used for image formation in a copying machine or the like.

[0002]

2. Description of the Related Art In an impingement type air current pulverizer using a jet jet, an object to be pulverized is supplied into the jet jet, the object to be pulverized is made to collide with an impact member, and the object to be pulverized is pulverized by the impact force. FIG. 6 is a configuration diagram for explaining an example of a pulverizing apparatus to which the present invention is applied. In the drawing, reference numeral 1 denotes a supply port of a pulverized material, 2 denotes a compressed air supply nozzle, 3 denotes a compressed air acceleration tube,
4 is a compressed air collision member, and 5 is a pulverized material discharge port. As shown in the figure, the pulverizer has a collision member 4 opposed to an acceleration pipe outlet 8 of an acceleration pipe 3 to which a compressed air supply nozzle 2 is connected. And
By the flow of the high-speed air flow 15 which is a jet jet by the acceleration tube 3, the crushed object 6 is sucked from the crushed object supply port 1 in the middle of the acceleration tube 3 to the acceleration tube 3, and this is injected together with the high-speed air flow 15, and , Into the crushing chamber 7 to collide with the collision surface 9 of the collision member 4, thereby crushing the material 6 to be crushed by the impact. Usually, in order to pulverize the object 6 to a desired particle size, a classifier 13 is disposed between the discharge port 5 and the supply port 1 to provide a closed circuit. At this time, as a result of classification by the classifier 13, in the case of coarse powder, the crushed material 6 that has become the coarse powder 11 is sent to the crushed material supply port 1, and the above-described pulverization is performed again. Classifier 1 from outlet 5
3 and classify again. As a result, it is possible to obtain a pulverized product having a desired particle size for the fine powder 12.

FIG. 7 is an enlarged view of the compressed air supply nozzle 2, the accelerating pipe 3 and the supply port 1 of the object to be pulverized in the pulverizing apparatus shown in FIG. 6. In the prior art, the accelerating pipe 3 has a Laval nozzle shape. However, the size of the cross-sectional areas 18 and 19 inside the accelerating tube 3 for each of the throat 16 and the supply port position 17 in the nozzle under the environmental conditions of the pulverization was not specified. For this reason, the conditions for increasing the speed of the airflow are unknown, and a further increase in the grinding efficiency has not been achieved.

[0004] Further, as the above-mentioned collision type air current pulverizer, for example, Japanese Patent Application Laid-Open Nos.
JP-A-15801 and JP-A-5-15802 have been proposed. In JP-A-4-48942, a plurality of toner supply ports are provided to supply toner to the nozzles in an axially symmetric manner. And Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 15801 aims to collect toner near the center of the nozzle to eliminate non-uniformity of toner density, to uniformly disperse and accelerate all the toner, Japanese Patent Application Laid-Open No. 5-15802 aims to provide a conical inclined member at a portion for supplying toner into a nozzle, collect fine powder, and pulverize only coarse powder. There is no description of the conditions for speeding up.

[0005]

As described above, in the impingement type airflow pulverizer, it is necessary to increase the airflow in order to increase the pulverization efficiency. No suggestions have been made for The present invention has been made in view of the above circumstances, and in particular,
The purpose of the present invention is to determine the optimum shape of the accelerating tube depending on the environmental conditions of the pulverization in the impingement type air flow pulverization apparatus, thereby improving the pulverization processing capacity.

[0006]

In order to solve the above-mentioned problems, the present invention provides (1) a jet nozzle for jetting a jet jet into a pulverizing chamber, and a supply port for supplying an object to be pulverized into the jet jet. In a pulverizing apparatus having a collision member having a collision surface that is installed to face the ejection nozzle and directly pulverizes the object to be pulverized with the jet jet to pulverize the object,
Determining the ejection nozzle cross-sectional area ratio or diameter ratio between the throat position and the supply port position in the ejection nozzle from the relationship between the pressure ratio and the cross-sectional area ratio or the diameter ratio corresponding to each nozzle position in the ideal gas according to the one-dimensional Laval nozzle theory. ,
Further, (2) in the pulverizing device in the above (1),
The cross-sectional area ratio or the diameter ratio is increased by an occupied cross-sectional integral with respect to a region where the object to be ground supplied from the supply port is located at or before and after the supply port in the nozzle; In the pulverizing device according to 2), the convex portions at both ends of the throat and the convex portions at the inlet of the supply port to the accelerating tube have a curvature. In the pulverizing device, the ejection nozzle has a wall surface opposed to the supply port formed in a convex shape in the nozzle inward direction , and a vicinity of the supply port.
That the wall surface is concave outside the nozzle ,
(5) The grinding device according to (4), wherein the convex shape and the concave shape have a curvature.

[0007]

In the impingement type air flow pulverizer, the throat position in the ejection nozzle and the ejection nozzle cross-sectional area ratio or diameter ratio at the supply port position are determined by the pressure ratio and the cross-sectional area corresponding to each nozzle position based on the one-dimensional Laval nozzle theory in an ideal gas. By deciding from the relationship of the ratio or the diameter ratio, the conditions for speeding up the airflow and speeding up the powder are clarified and used as a guide for high efficiency pulverization.

[0008]

FIG. 1 shows a method of determining the ratio of the cross-sectional area or the diameter of the jet nozzle at the position 17 of the throat 16 in the jet nozzle 3 and the position 17 of the supply port 1 of the material to be pulverized in the air-flow pulverizer according to the first embodiment. In the main part configuration diagram for explanation, the same reference numerals are given to portions having the same operation throughout the drawings. In FIG. 1, assuming that the cross-sectional area at the throat 16 is A *, the pressure is P *, the cross-sectional area inside the accelerating tube (ejection nozzle) 3 is A, and the pressure is P, the one-dimensional Laval nozzle theory of ideal gas is used. The relationship between the pressure ratio P / P * for the throat 16 and the cross-sectional area ratio A / A * is given by equation (1). Here, κ is a specific heat ratio (the specific heat ratio of air is κ = 1.4).

[0009]

(Equation 1)

The pressure at the compressed air supply nozzle 2 is P ₂
By approximating this to the stagnation point pressure, (2),
Equation (3) can be obtained.

[0011]

(Equation 2)

Actually, the pressure is measured at the supply port position 17 in the nozzle using a pitot tube or the like, and this pressure is used as the pressure P. At this time, the cross-sectional area A is the cross-sectional area at the supply port position 17 in the nozzle. Since the ratio P / P ₂ of the pressure P at the supply port position 17 in the nozzle and the pressure P ₂ at the compressed air supply nozzle 2 is determined from the measurement result, the cross-sectional area A at the supply port position 17 in the nozzle is determined by Expression (4). And the ratio A / A * of the cross-sectional area A * at the throat 16 is determined. Also, the square root of the cross-sectional area ratio A / A * √A / √A * is
This is the ratio of the diameter at the supply port position 17 in the nozzle to the diameter at the throat 16, and is expressed by the following equation (5).

[0013]

(Equation 3)

The sectional area A and the throat 16 at the supply port position 17 in the nozzle depend on the ratio P / P ₂ of the pressure P at the supply port position 17 in the nozzle and the pressure P ₂ at the compressed air supply nozzle 2. Ratio A / A * of cross-sectional area A * or aperture ratio √A
By adopting / √A * for the shape, the airflow is efficiently accelerated, and a higher-speed airflow 15 can be obtained. FIG.
Is a graph of Equations (4) and (5).

Table 1 shows an experimental example of the first aspect of the present invention. The raw materials are mixed with a mixer to obtain a mixture. Next, the mixture is melt-kneaded at about 200 ° C. with an extruder, and then cooled and solidified.
The particles were coarsely pulverized into particles having a size of 2000 μm, and this coarsely pulverized material was used as a material 6 to be pulverized. As a means 13 for classifying the pulverized material 10 into fine powder 12 and coarse powder 11, a fixed air classifier was used.

[0016]

[Table 1]

Actually, compressed air having a flow rate of 7 Nm ³ / min was introduced from the compressed gas supply nozzle 2 of the impingement type air flow pulverizer, and was supplied from the supply port 1 of the pulverized material at a rate of 32 kg / hr. At this time, the ratio of the diameter at the supply port position 17 in the nozzle to the diameter at the throat 16 is √A / √A * = 2.5. The pulverized material 10 is conveyed to a classifier 13 and is collected as a fine powder 12 if it is a fine powder, and is again pulverized as a coarse powder 11 from the pulverized material supply port 1 if it is a coarse powder. It was put into the acceleration tube 3 together with the object 6. As a result, 27.40 kg / hr (85.6% yield) of a pulverized product having a volume average particle size of 7.5 μm (measured with a Coulter counter) was recovered as the fine powder 12.

Next, a method of determining the sectional area ratio or the diameter ratio of the ejection nozzle between the throat position and the supply port position in the ejection nozzle in the air-flow type pulverizer according to the second aspect will be described. Using the same raw material as described in claim 1 (described in Table 1), pulverization was performed according to the operation flow using a pulverizer shown in FIG. The pulverized material 10 is divided into fine powder 12 and coarse powder 1
A fixed air classifier was used as the means 13 for classifying into one. Actually, compressed air at a flow rate of 7 Nm ³ / min was introduced from the compressed gas supply nozzle 2 of the impingement type air flow pulverizer, and was supplied from the supply port 1 of the pulverized material at a rate of 32 kg / hr. As a result, 10% of the cross-sectional area of the nozzle was occupied at the supply port position 17 in the nozzle by the crushed object 6 supplied from the crushed object supply port 1. That is, the diameter ratio is the ratio of the diameter at the supply port position 17 in the nozzle to the diameter at the throat 16 √A / √A * = 1.05 times 2.5 which is √A / √A * = 2.5.
2.62. The pulverized material 10 is supplied to a classifier 13
In the case of fine powder, it was collected as fine powder 12, and in the case of coarse powder, coarse powder 11 was again introduced into the acceleration tube 3 together with the crushed object 6 from the crushed object supply port 1. As a result, the fine powder 12 had a volume average particle size of 7.5.
27 μm (measured with a Coulter counter)
60 kg / hr (yield 86.25%) was recovered, and a steady powder effect was confirmed.

FIG. 3 is a schematic view of a main part for explaining the third aspect of the present invention. In the present invention, the convex shape of the wall surface of the throat 16 and the convexity of the entrance of the supply port 1 of the material to be ground 1 into the acceleration pipe 3 are shown. The same raw material (described in Table 1) as that of the experimental example of claim 1 was used, with a curvature of 20 added to the shape, and pulverization was performed according to the operation flow using a pulverizer shown in FIG. As a means 13 for classifying the pulverized material 10 into fine powder 12 and coarse powder 11, a fixed air classifier was used. 7 Nm ³ / m flow rate from compressed gas supply nozzle 2 of impingement type air flow crusher
in compressed air, and 30 kg from the supply port 1
/ Hr. At this time, the ratio of the diameter at the supply port position 17 in the nozzle to the diameter at the throat 16 is ΔA
/√A*=2.62. The pulverized material 10 is conveyed to a classifier 13 and is collected as a fine powder 12 if it is a fine powder, and is again collected as a coarse powder 11 from the supply port 1 of the material to be pulverized if it is a coarse powder. 6 together with the accelerator tube 3. As a result, the volume average particle diameter was 7.
5 μm (measured by Coulter counter) pulverized material 2
6.20 kg / hr (87.3% yield) was recovered.

FIG. 4 is a view for explaining the invention according to claim 4 of the present invention.
21 in the nozzle inward direction on the surface facing the nozzle , supply port position
Add a concave shape 22 in the nozzle outer direction to the wall near 17
At the same time, the cross-sectional area A at the supply port position 17 in the nozzle and the cross-sectional area A * at the throat 16 depending on the ratio P / P2 of the pressure P at the supply port position 17 in the nozzle to the pressure P2 at the compressed air supply nozzle 2. The ratio A / A * or the aperture ratio √A / √A * is adopted for the shape. As an experimental example in claim 4, the same raw material (described in Table 1) as in the experimental example in claim 1 was used, and pulverization was performed using a pulverizing apparatus shown in FIG. The pulverized material 10 is turned into fine powder 12
As a means 13 for classifying the powder into coarse powder 11 and a coarse powder 11, a fixed air classifier was used. Actually, compressed air having a flow rate of 7 Nm3 / min was introduced from the compressed gas supply nozzle 2 of the impingement type airflow pulverizer, and supplied at a rate of 32 kg / hr from the supply port 1 of the material to be pulverized. At this time, the ratio of the diameter at the supply port position 17 in the nozzle to the diameter at the throat 16 is √A / √A * = 2.62.
It is. The crushed material 10 is transported to a classifier 13,
If it is a fine powder, it is collected as a fine powder 12, and if it is a coarse powder, it is again fed into the acceleration tube 3 together with the crushed object 6 from the crushed object supply port 1 as the coarse powder 11. As a result, a fine powder having a volume average particle size of 7.5 μm (measured with a Coulter counter) of 28.00 kg / hr (yield 8
(7.5%).

FIG. 5 is a schematic view of the essential part for explaining the fifth aspect of the present invention. In the present invention, a curvature 23 is added to the convex shape 21 and the concave shape 22 shown in FIG. inner supply opening position of the pressure P ₂ at the pressure P and the compressed air feed nozzle 2 at 17 the ratio P / P ₂ in the cross-sectional area a and the throat 16 of the nozzle in the supply port position 17 dependent cross-sectional area a * of Ratio A / A
* Or the diameter ratio √A / √A * is adopted for the shape. As an experimental example in claim 5, the same raw materials as those in claim 1 (described in Table 1) were used, and pulverization was performed using a pulverizer shown in FIG. As means 13 for classifying the pulverized material 10 into fine powder 12 and coarse powder 11, a fixed air classifier was used. Actually, compressed air having a flow rate of 7 Nm ³ / min was introduced from the compressed gas supply nozzle 2 of the impingement type air flow pulverizer, and supplied at a rate of 30 kg / hr from the supply port 1 of the material to be pulverized. At this time, the ratio of the diameter at the supply port position 17 in the nozzle to the diameter at the throat 16 is √A / √A * = 2.62. The pulverized material 10 is conveyed to a classifier 13, and is collected as a pulverized material 12 when it is a fine powder, and a pulverized material 11 when it is a coarse powder.
Then, the material to be crushed 6 was again charged into the acceleration tube 3 together with the crushed material 6 from the crushed material supply port 1. As a result, 26.5 kg / hr (yield: 88.3%) of a pulverized product having a volume average particle size of 7.5 μm (measured by a Coulter counter) was recovered as fine powder.

[0022]

According to the present invention, the object to be crushed is supplied into the jet jet by using the jet jet, and the object to be crushed collides with the collision surface, and the object to be crushed is generated by the collision force. In the collision-type powder pulverizer for pulverizing, the throat position in the ejection nozzle and the ejection nozzle cross-sectional area ratio or the diameter ratio of the supply port position, the pressure ratio corresponding to each nozzle position according to the one-dimensional Laval nozzle theory in ideal gas. By deciding from the relationship between the cross-sectional area ratio or the diameter ratio, the conditions for speeding up the airflow and speeding up the powder can be clarified, and can be used as a guide for high-efficiency pulverization. (2) Effects corresponding to claim 2 A collision type in which an object to be crushed is supplied into a jet jet using a jet jet, the object to be crushed collides against an impact surface, and the object to be crushed is crushed by the impact force. In the crusher, the object to be crushed supplied from the supply port is increased in the sectional area ratio or the diameter ratio by the occupied sectional integral with respect to the supply port in the nozzle or a region located before and after the supply port, so that a steady air flow is obtained. The speed of the powder and the speed of the powder can be increased, and highly efficient pulverization becomes possible. (3) Effect according to claim 3 A collision type in which an object to be crushed is supplied into a jet jet using a jet jet, the object to be crushed collides with an impact surface, and the object to be crushed is crushed by the impact force. In the crusher, the convex part at both ends of the throat and the convex part at the inlet of the front supply port to the acceleration tube have a curvature to reduce the pressure loss of the airflow existing in claim 2. Thus, highly efficient pulverization becomes possible. (4) Effects corresponding to claim 4 A collision type in which an object to be crushed is supplied into a jet jet using a jet jet, the object to be crushed collides against an impact surface, and the object to be crushed is crushed by the impact force. in mills, the direction in nozzle nozzle wall surface facing in the vicinity of the supply port located
And the wall near the supply port of the nozzle is
By having a concave shape in the outward direction of the nozzle , the chance of the crushed object supplied from the supply port colliding with the lower wall of the acceleration tube is increased as compared with the invention of claim 2, and the dispersibility of the crushed object is increased. This increases the chances that the object to be crushed uniformly collides with the lower wall surface of the accelerating tube, thereby increasing the dispersibility of the object to be crushed. Thereby, the object to be crushed is uniformly accelerated by the airflow, and more efficient crushing is possible. (5) Effects corresponding to claim 5 A collision type in which an object to be crushed is supplied into a jet jet using a jet jet, the object to be crushed collides against an impact surface, and the object to be crushed is crushed by the impact force. In the pulverizer, the convex shape and the concave shape according to the fourth aspect of the invention have a curvature to reduce the pressure loss of the airflow existing in the fourth aspect of the present invention, thereby increasing the speed of the airflow with high efficiency. Can be planned.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram for describing the invention described in claim 1;

FIG. 2 is a diagram showing a relationship between a pressure ratio and a nozzle sectional area ratio or a bore diameter ratio depending on the pressure ratio.

FIG. 3 is a main part configuration diagram for explaining the invention described in claim 3;

FIG. 4 is a main part configuration diagram for explaining the invention described in claim 4;

FIG. 5 is a main part configuration diagram for explaining the invention described in claim 5;

FIG. 6 is an overall configuration diagram for explaining an example of a crusher to which the present invention is applied.

FIG. 7 is an enlarged configuration diagram of a main part of the crusher shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pulverized material supply port, 2 ... Compressed air supply nozzle, 3 ... Compressed air acceleration pipe (spout nozzle), 4 ... Compressed air collision member,
5: crushed material outlet, 6: crushed material, 7: crushing chamber, 8: acceleration tube outlet, 9: collision surface, 10: crushed material, 11: coarse powder, 1
2: fine powder, 13: classifier, 15: high-speed air flow (jet jet), 16: slot, 17: position of supply port in nozzle, 1
8, 19 ... sectional area, 20, 21, 22, 23 ... shape.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirosato Amano 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Keiko Watanabe 1-3-6 Nakamagome, Ota-ku, Tokyo (56) References JP-A-5-309287 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B02C 19/06

Claims (5)

(57) [Claims] 1. A jet nozzle for jetting a jet jet into a crushing chamber, a supply port for supplying an object to be crushed into the jet jet, and a jet port provided opposite to the jet nozzle, the object to be crushed together with the jet jet. In a crusher having a collision member having a collision surface that is directly crushed and finely crushed,
Determining the ejection nozzle cross-sectional area ratio or diameter ratio between the throat position and the supply port position in the ejection nozzle from the relationship between the pressure ratio and the cross-sectional area ratio or the diameter ratio corresponding to each nozzle position in the ideal gas according to the one-dimensional Laval nozzle theory. Crushing device characterized by the above-mentioned. 2. The crushing apparatus according to claim 1, wherein the object to be crushed supplied from the supply port is occupied by the occupied sectional integral with respect to a supply port in a nozzle or a region located before and after the supply port. A crushing device characterized by an increase. 3. The crushing device according to claim 2, wherein the protrusions at both ends of the throat and the protrusions at the inlet of the supply port to the acceleration tube have a curvature. . 4. The crushing device according to claim 2, wherein the ejection nozzle has a wall facing the supply port inward of the nozzle.
And the wall near the supply port is a nozzle.
A crushing device characterized by having a concave shape in an outward direction . 5. The crushing device according to claim 4, wherein the convex shape and the concave shape have a curvature.