JP5269404B2 - Jet mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a jet mill which keeps simpler and more compact structure than conventional one and provides improved classification precision by preventing so-called plunging phenomenon (the phenomenon wherein uncrushed matter flows into a classification zone). <P>SOLUTION: The jet mill is provided with: a mill body 1 having a hollow chamber a; a raw material supplying means 3 introducing a raw material to the hollow chamber a; a discharging part 2 installed nearly in the center of the hollow chamber a; and a jetting means 4 forming a swirling flow in the hollow chamber a, and the jet mill forms a crushing zone for crushing the raw material introduced by the swirling flow and the classification zone for classifying the crushed matter and discharging it from the discharging part 2, wherein the discharging part 2 has a cylindrical part 20 protruded into the hollow chamber a and provided in a standing condition nearly in the center of the lower wall part 11, and a flange 5 disposed on the outer circumference of the cylinder part. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a horizontal swirling flow jet mill suitable for ultra-fine pulverization and pulverization, in which a classification zone is formed together with a pulverization zone by a swirling flow using a high-pressure fluid among pulverizers.

  The jet mill shown in FIGS. 5 (a) and 5 (b) is a basic example of a horizontal swirling flow type disclosed in Japanese Patent Application Laid-Open No. 52-44450. In this structure, the mill main body forms an annular cavity chamber (crushing chamber) 43, provided with raw material supply means (hopper 41, nozzle 42, etc.) for introducing the raw material into the cavity chamber 43, and provided substantially at the center of the cavity chamber 43. And a discharge means (such as a discharge pipe 48 with a cylindrical portion 49 protruding into the hollow chamber) and an injection means (a supply pipe 44, an air chamber 45, an annular wall 46) that forms a swirling flow of high-pressure fluid in the hollow chamber 43. Provided nozzle 47 and the like). Then, the high-pressure fluid is supplied to the hollow chamber 43 from the air supply pipe 44 to the air chamber 45 and is jetted from a nozzle 47 arranged with an injection angle β on the annular wall 46, so that a swirling flow, that is, an outer grinding zone and And an inner classification zone. The raw material of the hopper 41 is injected and supplied from the nozzle 42 arranged at an angle α to the radius of the cavity chamber 43 on the outer peripheral side in the cavity chamber 43 to the grinding zone side in the cavity chamber. Then, the raw material is pulverized exclusively by the collision of the raw materials in the swirling flow of the pulverization zone. This pulverized product is carried to the inner classification zone, and the target fine particles ride on the swirling flow and enter and exit from the inlet of the cylindrical portion 49, and coarse particles having a diameter larger than the classification diameter are again pulverized by the centrifugal force of the swirling air flow. It is skipped and re-pulverized.

Japanese Patent Publication No. 7-67541

  In the above jet mill, for example, the high-pressure swirling flow for pulverization and classification is disturbed by the air flow for supplying the raw material, so that the raw material powder flows into the classification zone without being pulverized and is discharged together with the pulverized product. In other words, it is difficult to completely eliminate the so-called jump-in phenomenon, and the classification accuracy is deteriorated due to such jump-in phenomenon, and the quality control is bothered. Therefore, the technology of Patent Document 1 includes, as such a countermeasure, a raw material supply port provided directly above the discharge unit, a rotor including a motor and a dispersion plate rotated by a drive shaft, and the raw material is supplied to the raw material supply port. It is dropped onto a rotating dispersion plate from above and is moved and dispersed to the outer peripheral side of the cavity chamber by centrifugal force. However, in this structure, the support mechanism for the rotor and the motor for the rotor are indispensable and complicated, so that, for example, disassembly during cleaning becomes difficult. In addition, the installation space is expanded, and the apparatus cost is increased.

  The present invention is directed to a horizontal swirl type jet mill, and while maintaining simplification and compactness of the apparatus as compared with the conventional structure, it prevents a jumping phenomenon, improves classification accuracy, and reduces pulverized particle size variation. The purpose is to make it smaller.

To achieve the above object, the present invention provides a mill main body having a substantially annular cavity chamber defined by upper and lower walls and a surrounding annular wall, a raw material supply means for introducing a raw material into the hollow chamber, and the cavity A discharge section provided substantially at the center of the chamber, and an injection means for forming a swirl flow in the hollow chamber, and classifying a pulverization zone and a pulverized product by crushing the introduced raw material by the swirl flow (design) In the jet mill that forms a classification zone that allows discharge from the discharge part while feeding the upper particle size or the one that has reached the particle size to the discharge part side and returning the other particles to the grinding zone again) is cylindrical portion is erected in the substantial center protrudes into the cavity chamber of the inner lower wall section of the upper and lower wall portion which defines a pre-Symbol hollow chamber, and a substantially horizontally disposed to the distal end outer periphery of the cylindrical portion and it has a flange, and set on the outer periphery of the tubular portion Is a prevention protruding portion reservoir reduces progressively projecting amount toward the flange from the lower wall portion out of the upper and lower walls of the hollow chamber (see FIG. 3 (a)),

The raw material supply means has a supply pipe provided in a state penetrating the upper wall portion and the flange defining the hollow chamber, or in a state penetrating the peripheral annular wall defining the hollow chamber. The discharge port of the supply pipe is disposed substantially flush with the lower surface of the flange or below the lower surface so as to inject the raw material between the flange and the lower wall portion. .

  The invention of claim 1 has a simple structure in which a flange is added, so that the raw material injected from the raw material supply means flows into the cylindrical portion inlet of the discharge portion without being pulverized and is discharged together with the pulverized material. Can be almost eliminated, thereby improving classification accuracy and simplifying quality control. Here, the flange of the present invention is restricted so that the raw material injected from the raw material supply means does not fly to the cylindrical portion inlet side of the discharge portion so as to reach the crushing zone of the hollow chamber at a position below the cylindrical portion inlet of the discharge portion. Any shape and mounting structure may be used.

Further, the present invention prevents the swirling flow formed by the injection means from being disturbed as much as possible by arranging the flange substantially horizontally in the cavity chamber , and, as shown in the example of FIG. The dead space (location where the swirling flow does not spread due to vortex or turbulent flow) that is likely to occur in a is eliminated by the accumulation preventing overhanging portion 9 to improve the grinding efficiency.

  A preferred embodiment of the present invention will be described with reference to the drawings. 1 is a schematic cross-sectional view showing a jet mill according to an embodiment, FIG. 2 is a schematic view showing a modification of the flange, FIG. 3 shows a modification of the hollow chamber, and FIG. 4 is a modification of the raw material supply means and the injection means. Show. In addition, in the following description, the same code | symbol is attached | subjected to the same member and site | part operatively, and the overlapping description is omitted as much as possible. Of course, this invention is not restrict | limited at all by the following forms and modifications.

As shown in FIG. 1, the jet mill in the form of (apparatus structure) includes a mill main body 1 that forms a main cavity chamber a on the center side and a sub-cavity chamber b on the outer periphery thereof, and an abbreviation of the main cavity chamber a. The discharge part 2 which takes out the pulverized material (product) crushed (including crushing) and classified by being provided in the center, the upper and lower wall parts 10 and 11 partitioning the cavity chambers a and b, and the upper and lower wall part 10 , 11 are disposed in a state of penetrating the upper wall portion 10 to introduce a raw material (powder raw material) into the main cavity chamber a, and a swirling flow by a high-pressure fluid is introduced into the main cavity chamber a. A pulverization zone for pulverizing powder, which is a raw material introduced into the main cavity chamber a by a swirling flow formed through the injection means 4, including the injection means 4 to be formed, and the like A classification zone is formed that enables discharge from the discharge section 2 while classifying the pulverized material pulverized in the pulverization zone. To. Note that the jet mill of the invention may be a horizontal swirl type as described above.

  The jet mill described above has, as a main part structure, an inner cylinder member 20 in which the discharge part 2 is erected substantially at the center of the lower wall part 11 of the upper and lower wall parts 10 and 11 and protrudes into the main cavity chamber a. The flange 5 is attached to the outer periphery of the inner cylinder member 20 and regulates the raw material introduced from the raw material supply means 3 so as not to fly to the inlet side of the inner cylinder member 20.

  Here, the mill main body 1 forms a main cavity chamber a inside the inner wall 12 by disposing the annular inner wall 12 and the annular outer wall 13 between the upper wall 10 and the lower wall 11. In addition, a sub-cavity chamber b for the air supply chamber is defined between the inner wall 12 and the outer wall 13. In the lower wall portion 11 of FIG. 1, a through hole 6 is provided substantially at the center, and a recess 11 a centering on the through hole 6 is provided inside the lower wall portion 11. However, the mill main body of the present invention may have a configuration in which the sub-cavity b is omitted as in the modification of FIG.

  The discharge part 2 protrudes in the recess 11a of the lower wall part 11 and protrudes in the main cavity chamber a, and the outer part of the lower wall part 11 is in communication with the inner cylinder member 20. And a connecting cylinder member 21 projecting from the connector. The inner cylinder member 20 and the connecting cylinder member 21 have flange portions 20a and 21a in which the corresponding attachment end side is bent. And the inner cylinder member 20 is arrange | positioned in the state by which the flange part 20a was fitted by the recess 11a with respect to the inner surface of the lower wall part 11. FIG. In the connecting cylinder member 21, the inner diameter of the flange portion 21 a is arranged coaxially with the through hole 6 and the inner cylinder member 20 with respect to the outer surface of the lower wall portion 11. From that state, the fastener S is fastened and locked to the flange portion 21 a, the corresponding portion of the lower wall portion 11, and the flange portion 20 a, so that the inner cylindrical member 20 and the connecting cylindrical member 21 are integrated with the lower wall portion 11. Combined. The mounting structure of the inner cylinder member 20 and the connecting cylinder member 21 may be other means such as adhesion or welding.

  The raw material supply means 3 includes a supply pipe 30 connected to the upper wall 10 or the inner wall 12 at a predetermined position and angle, a hopper 31 connected to the supply pipe 30, a nozzle 32, and the like. Yes. When the raw material enters the supply pipe 30 from the hopper 31, the raw material is jetted and supplied to the pulverization zone of the main cavity chamber a together with the high-pressure fluid pumped from the nozzle 32. In addition, the raw material supply means 3 includes, for example, a Laval nozzle configuration in which a high-pressure fluid supply pipe and an acceleration pipe are combined, or a configuration provided at a plurality of locations depending on the physical properties and supply amount of the raw material powder.

  The injection means 4 is assembled to the sub-cavity b, the air supply pipe 41 for introducing the high-pressure fluid from the outside into the sub-cavity b, and the high-pressure fluid in the sub-cavity b being injected into the main cavity a. And a nozzle 40 that performs the above operation. The nozzles 40 are respectively attached to portions equally divided with respect to the periphery of the inner wall 12, and are provided in a state inclined at a predetermined angle with respect to the diameter direction of the inner wall 12.

  When the high-pressure fluid is jetted from the nozzle 40, the above jetting means 4 forms a pulverization zone in the main cavity chamber a by the swirling flow caused by the jetting, away from the center, and forms a classification zone in the central side. For example, the subcavity b may be omitted and the high pressure fluid may be directly supplied to each nozzle 40. In the pulverization zone, the raw materials are accelerated and collide with each other or collide with the surrounding wall surface and are pulverized. In this case, as shown in Japanese Patent No. 3087201, the pulverization zone includes a collision plate for promoting pulverization and rectification. A plate may be attached. In the classification zone, among the pulverized products pulverized in the pulverization zone, those having reached a predetermined particle size or particle size are transferred from the pulverization zone and classified, and then the inner cylinder member 20 constituting the discharge unit 2 and the connection It is discharged outside through the cylindrical member 21.

  The flange 5 is a smooth flat plate such as an elliptical shape, has a large hole 5 a that passes through the upper end side of the inner cylinder member 20, and is coupled to the inner cylinder member 20 in a substantially horizontal state. Further, the flange portion 5 has a small hole 5b through which the distal end side of the supply pipe 30 is passed, the upper end outer periphery of the inner cylinder member is engaged with the large hole 5a with respect to the inner cylinder member 20, and the periphery is welded. In some cases, they are coupled in a substantially horizontal state. The small hole 5b is an oblique hole into which the distal end portion of the supply pipe 30 is inserted and engaged. However, a part of the ellipse is cut into a small arc, and the distal end portion of the supply pipe 30 is located above the flange along the notch. To the flange lower surface side. In this case, the tip of the supply pipe 30 is substantially flush with the lower surface of the flange 5 in a state of passing through the small hole 5b of the flange 5 so as not to disturb the injection direction of the raw material injected from the discharge port, or the flange 5 It is preferable to protrude downward by a slight amount.

  Here, the flange 5 is elongated in the injection direction of the supply pipe 30, and when the raw material is injected from the supply pipe 30, the flange 5 does not fly to the inlet of the inner cylinder member 20, that is, above the flange 5. Thus, it leads to the pulverization zone of the hollow chamber a. For this reason, the raw material injected from the supply pipe 30 (the nozzle 32 of the raw material supply means 3) is reliably regulated by the flange 5 so as not to fly to the inlet side of the discharge portion side inner cylinder member 20.

(Operation) In the above jet mill, when the raw material is supplied from the raw material supply means 3 to the main cavity chamber a, the presence of the flange 5 described above ensures that the raw material is supplied to the pulverization zone of the main cavity chamber a. Of the swirling flow of the high-pressure fluid ejected from the nozzle 40, the high-speed fluid is accelerated in the crushing zone formed on the outer peripheral side of the main cavity chamber a and collides with each other or collides with the inner wall 12. The crushed material is classified in a classification zone formed at the center side of the main cavity chamber a, and is discharged to the outside through the inner cylinder member 20 and the connecting cylinder member 21. That is, in this structure, the addition of the flange 5 eliminates the occurrence of a jumping phenomenon that flows into the inlet of the inner cylinder member 20 without being pulverized as in the prior art and is discharged together with the pulverized material, thereby improving the classification accuracy. To improve quality and simplify quality control.

(Modification of FIG. 2) FIG. 2 (a) shows an example in which two raw material supply means 3 are provided. In this example, the flange 5A is a substantially disk-shaped smooth flat plate, and a large hole 5a is provided at the center, and a small hole 5b is provided in pairs with the large hole 5a interposed therebetween. Each small hole 5b is an oblique hole to which the tip end portion of the corresponding supply pipe 30 is inserted and engaged, but a part of a circle is cut into a small arc and the tip end portion of the supply pipe 30 is along the cutout. It may be arranged from the upper side of the flange to the lower side of the flange.

  FIG. 2B is an example when the flange 5B is attached to the raw material supply means 3 side. In this example, the flange 5B is a fan-shaped smooth flat plate, and has an inner arcuate cutout portion 5c that abuts the outer periphery of the inner cylinder member 20, and a small hole 5b that passes the distal end side of the supply pipe 30. The front end of the supply pipe 30 is engaged with the small hole 5b and welded to the supply pipe 30 in a substantially horizontal state. The small hole 5b is an oblique hole into which the distal end portion of the supply pipe 30 is inserted and engaged. However, a part of the fan-shaped outer side is notched, and the distal end portion of the supply pipe 30 is formed along the notch from above the flange. You may arrange | position to the flange lower surface side. As described above, the flanges 5, 5 </ b> A, 5 </ b> B of the present invention can be variously deformed in addition to their shapes.

(Modification of FIG. 3) FIG. 3 (a) shows an example in which the upper wall portion 10 constituting the mill body 1 is hat-shaped. In other words, the mill body 1 has a configuration in which the through hole 7 is formed in the central portion of the upper wall portion 10 and the through hole 7 is closed by the reverse concave outer cylinder member 8. The through hole 7 is a hole having a larger diameter than the through hole 6 of the lower wall portion 11. The outer cylinder member 8 has a flange portion 8a bent at the attachment end side, and is arranged so that the inner diameter of the flange portion 8a is positioned on the same axis as the through hole 7 and the inner cylinder member 20, and then the flange portion 8a is fastened. By being fastened and locked to the corresponding portion of the upper wall portion 11 by the tool S1, the upper wall portion 10 is integrally coupled. In this structure, for example, the classification zone formed between the upper wall portion 10 and the flange 5 is expanded by the reverse concave shape of the outer cylinder member 8, and as a result, improvement in classification efficiency is expected.

  In FIG. 3B, the outer cylindrical member 8A is further formed in a deep reverse concave shape, and the entire length of the inner cylindrical member 20 is lengthened, and the elongated cylindrical upper portion 25 is formed inside the reverse concave shape of the outer cylindrical member 8A. It has a configuration protruding. In other words, the discharge portion 2 includes an inner cylinder member 20 protruding from the lower wall portion 11, extending toward the upper wall portion 10 so as to cross the cavity chamber a in the vertical direction, and attached to the upper wall portion 10. The outer cylinder member 8 </ b> A has a discharge cylinder upper extension 25 disposed in a reverse concave shape with the discharge auxiliary path gap c and the secondary classification gap d maintained. For this reason, among the pulverized materials pulverized in the pulverization zone, the pulverized material that has entered the classification zone of the hollow chamber a is classified in the classification zone, and then passes through the discharge auxiliary path gap c and the secondary classification gap d. Therefore, it is possible to classify with high accuracy and discharge from the cylinder extension 25. This structure is disclosed in Japanese Patent Application No. 2006-18375. In addition to the primary classification in the classification zone, the pulverized material entering the classification zone is passed through the discharge auxiliary path gap c and the secondary classification gap d. The classification accuracy is improved again (secondary classification), thereby improving the classification accuracy by suppressing the variation in particle size or particle size without impairing the simplification and compactness of the device compared to the conventional structure. .

(Modification of FIG. 4) In this modification, the subcavity b is omitted from the jet mill of FIG. 1, and the annular wall 14 defining the main cavity chamber a (this annular wall is the inner wall of FIG. 1). 12), the nozzle device 42 constituting the injection means 4A is provided at each of the four equally divided locations. Each nozzle device 42 is connected to a high-pressure fluid supply unit (not shown) by piping or the like, and injects high-pressure fluid in the same manner as the nozzle 40 in FIG. Further, in this modification, a so-called tangential supply method is adopted in which the supply pipe 30 of the raw material supply means 3 is arranged with a predetermined angle on the annular wall 12 defining the main cavity chamber a. As described above, even when the supply pipe 30 is disposed via the annular wall 12, when the raw material is injected from the supply pipe 30, the raw material is introduced into the inlet of the inner cylinder member 20, that is, the flange due to the presence of the flange 5. 5 so that it does not fly above 5, and is guided to the grinding zone of the main cavity chamber a. For this reason, also in this case, the raw material injected from the supply pipe 30 of the raw material supply means 3 is reliably regulated by the flange 5 so as not to fly to the inlet side of the discharge portion side inner cylinder member 20. The supply pipe 30 is provided with a tip substantially coincident with the inner peripheral surface of the annular wall 12, but may be protruded to the lower side of the flange 5. Further, the shape of the flange 5 described above may be an umbrella or a dish shape in which the peripheral portion is curved slightly downward or upward.

(Embodiment) Next, the effectiveness of the present invention will be clarified by a test example in which fine pulverization is performed using the above jet mill.

  In this test example, the jet mill used has the tangential supply system shown in FIG. 4, the inside diameter of the hollow chamber (the main hollow chamber a in FIG. 4, that is, the grinding chamber) is 312 mm in diameter, and the height of the outer peripheral portion of the hollow chamber is Is 50 mm, the inner diameter of the discharge part at the center bottom of the cavity chamber is 70 mm in diameter, and there are four nozzles for injection means (nozzle device in FIG. 4) provided at the outer periphery of the cavity chamber and divided into four equal parts. , And a nozzle for raw material supply means (supply pipe in FIG. 4), and has no sub-cavity chamber. As a raw material, calcium carbonate (manufactured by Maruo Calcium Co., Ltd., having a median diameter of 115 μm) was used and pulverized under the following conditions.

That is, in the first and second embodiments, the discharge portion is a cylindrical portion having a height (projection dimension) of 53 mm that stands upright at the center of the lower wall portion of the upper and lower wall portions of the hollow chamber and protrudes into the hollow chamber. In addition, a flange (a circular flange made of SUS304, having a diameter of 212 mm and a thickness of 5 mm) is attached to the outer periphery of the protruding end side of the cylindrical portion. The pulverization conditions are 6 kg / cm ² , the air volume is 2.5 It was performed at a setting of ˜2.6 m ³ / min. On the other hand, in the comparative examples 1 and 2, it performed on the same grinding | pulverization conditions as the said Example except the structure to which a discharge part does not have a flange in a cylinder part outer periphery. The particle size distribution was measured with a Microtrac particle size distribution measuring device MT3300EXII (manufactured by Nikkiso Co., Ltd.). Table 1 lists the pulverization results.

(Table 1)

  As is clear from Examples 1 and 2 and Comparative Examples 1 and 2, the jet mill discharge part has a flange disposed on the outer periphery of the cylindrical part protruding into the hollow chamber as in the present invention. As a result, mixing of coarse particles, which has been a problem until now, has been greatly improved, a median diameter has been reduced, and a pulverized product having a sharp particle size distribution has been obtained. As described above, it has been found that, as the jet mill, the cylinder portion of the discharge portion has the flange on the outer periphery, thereby improving the classification performance and improving the processing speed.

(A) is a schematic longitudinal cross-sectional view which shows the jet mill of this invention form, (b) is an AA arrow directional cross-sectional view of (a). (A) And (b) is a schematic diagram which shows the modification of a flange. (A) And (b) is a schematic cross section which shows the modification of a mill main body or a discharge part. (A) And (b) is a schematic cross section which shows the modification which changed the injection means etc. FIG. (A) And (b) is a figure which shows the basic form of the horizontal swirling flow type jet mill disclosed by patent document 1. FIG.

Explanation of symbols

1 ... Mill body (10 and 11 are upper and lower walls, 12 and 13 are inner and outer walls)
2 ... discharge part (21 is a cylinder member for connection)
3. Raw material supply means (30 is a supply pipe, 31 is a hopper, 32 is a nozzle)
4, 4A ... injection means (b is a sub-cavity chamber, 40 is a nozzle, 41 is an air supply pipe)
5, 5A, 5B ... Flange 6, 7 ... Through hole 8, 8A ... Outer cylinder member
DESCRIPTION OF SYMBOLS 9 ... Overhang | projection part 14 for pool prevention ... The annular wall of a mill main body 42 ... Nozzle apparatus 20 ... Inner cylinder member (cylinder part)
a ... Main cavity (cavity)
b ... Sub-cavity chamber c ... Clearance for auxiliary discharge path d ... Clearance for secondary classification

Claims (1)

A mill main body having a substantially annular cavity chamber defined by an upper and lower wall part and a surrounding annular wall, a raw material supply means for introducing a raw material into the cavity chamber, and a discharge part provided substantially at the center of the cavity chamber And a pulverizing zone for pulverizing the raw material introduced by the vortex flow, and a classification zone for discharging the pulverized material from the discharge part while classifying the pulverized material. In the forming jet mill,
The discharge section, front Symbol cylindrical portion is erected in the substantial center protrudes into the cavity chamber of the inner lower wall section of the upper and lower wall portion which defines a cavity chamber, and a substantially horizontal at the tip outer periphery of the cylindrical portion It has arranged to have flanges, as well as the prevention protruding portion reservoir reduces progressively projecting amount from the lower wall portion toward the flange out of the upper and lower walls of the hollow chamber is provided on the outer periphery of the tubular portion ,
The raw material supply means has a supply pipe provided in a state penetrating the upper wall portion and the flange defining the hollow chamber, or in a state penetrating the peripheral annular wall defining the hollow chamber. And a discharge port of the supply pipe is disposed substantially flush with or below the lower surface of the flange so as to inject the raw material between the flange and the lower wall portion. mill.

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