JP2006255519A - Medium circulation type crusher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medium circulation type crusher permitting treatment of a high-viscosity slurry, capable controlling the tendency of the medium being pressed toward the outlet side and eliminating the possibilities of rising of the inside pressure of the vessel and heat generation. <P>SOLUTION: On the rotor of a stirring member, grooves having a width measured in the direction of the rotor axis twice the diameter of the stationary pin are formed on the cylindrical surface opposing the stationary pin protruding from the vessel in respective directions of the axis of the stationary pin. The grooves cause the crushing medium to move and circulate in the radial outward direction owing to centrifugal force received from the side wall of the grooves. The momentum of the crushing medium increases even in the region in the vicinity of the stationary pin usually serving as a static region, resulting in an increase of the amount of the slurry transported through transferring. Since the cross-section allowing the slurry to pass through increases, the passing resistance of the slurry decreases, the pressure loss in the vicinity of the stationary pin lowers, and the crushed amount increases, permitting treatment of a high-viscosity slurry. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pulverizing apparatus for pulverizing an object to be pulverized into fine particles, and in particular, a stirring member having a stirring pin is rotatably disposed in a hollow cylindrical vessel, and the space between the inner surface of the vessel and the stirring member. The present invention relates to a medium agitation type pulverization apparatus in which a pulverization medium is filled in a pulverization chamber formed in the above.

  The medium stirring type pulverizer is mainly used in the form of a wet apparatus, and is widely used for fine pulverization of ceramic raw materials, chemical products, pigments, foods, pharmaceuticals, and the like. For example, in the case of pigments such as ink and paint, pulverization to a very fine particle size is required, and such pulverization to an ultrafine particle size is sometimes called dispersion. In the present invention, the term pulverization is used in the sense of including such dispersion to an ultrafine particle size.

  In the wet pulverization apparatus, a material to be pulverized is supplied to the apparatus as a slurry suspended in a liquid vehicle. The medium agitation type pulverizer initially used a disc type agitation member called a disk type. In a pulverizing apparatus provided with a disk-type stirring member, no stationary pin is provided on the inner wall of the vessel. The slurry used had a viscosity of about 3000 cp and was mainly used for pulverization of paint pigments. In this disk-type pulverizing apparatus, a relative movement occurs between the outer peripheral edge of the disk and the inner wall surface of the vessel, and as a result, a circumferential shear region is formed, and this shear region contributes to the pulverizing action.

  The medium agitation type pulverizer has been used steadily thereafter, and has been applied to pulverization of high viscosity slurry. However, it has been found that when a pulverizer equipped with a disk-type stirring member is used for a high-viscosity slurry, a phenomenon occurs in which the slurry rotates together with the disk of the stirring member, resulting in a decrease in the pulverizing action.

  Through the progress of such development, in order to prevent the phenomenon that the slurry co-rotates with the disk, a pulverizing apparatus including a pin-type stirring member has been developed. This type of apparatus includes a stirring member including a rotor having a cylindrical surface and a plurality of stirring pins arranged at intervals in both the axial direction and the circumferential direction so as to protrude radially from the cylindrical surface of the rotor. On the inner surface of the vessel, a plurality of stationary pins are arranged at intervals in the radial direction so as to protrude radially inward at positions between the stirring pins of the stirring member when viewed in the axial direction. This type of medium stirring type pulverizer is described in, for example, Japanese Patent Publication No. 2-10699 ([Patent Document 1]). In this pin type pulverizer, as in the disk type pulverizer, a circumferential shear region is formed between the tip of the stirring pin and the inner wall surface of the vessel. Furthermore, around the agitation pin, the medium is driven in the circumferential direction by the agitation pin to form a high speed region, and on the contrary, around the stationary pin, the medium is disturbed by the stationary pin, Movement is slow and a relative rest area is formed. A radial shear region is formed on both sides of the stirring pin in the axial direction of the apparatus due to the speed difference between the high speed region and the stationary region. Therefore, since the slurry passing through the vessel must pass through the circumferential shear region or the radial shear region, the grinding efficiency is greatly improved as compared with the disk type.

  In the medium agitation type pulverizer, the slurry pumped into the pulverization chamber from the slurry inlet of the vessel is transferred between the medium and the medium in the process of contact between the moving pulverization media, and between the media. It is sent to the slurry outlet in the form of a passing stream that flows through. Transfer transfer is most effective for crushing.

  The above pulverizer is not problematic when the slurry viscosity is low, but encounters problems when the slurry becomes highly viscous. That is, as the slurry viscosity increases, the passage resistance increases accordingly. However, since the moving speed of the medium is low in the stationary region, transfer transfer is small and most of the passage flows, so the medium exits due to the high passage resistance. It tends to be pushed to the side. As a result, the internal pressure in the vessel increases, the medium generates heat, the processing amount decreases, or sometimes the processing becomes impossible.

  Among the many applications in which a medium agitation type pulverizer is used, in the case of a specific application, for example, a drying process is performed following a pulverization process, such as an application of ferrite for electronic parts or barium titanate for capacitors. In some cases, very high viscosity slurries are used to reduce the amount of water as much as possible in preparation for the drying process. Further, offset printing ink, screen printing ink, and the like are required to be pulverized with a high viscosity of tens of thousands of cp. Conventional medium agitation type pulverizers have many problems in handling such high-viscosity slurries, and therefore, high-viscosity slurries are generally processed by an apparatus such as a roll mill with low production efficiency. It was.

Japanese Patent Publication No. 2-10699

  With the above problems in the conventional medium agitation type pulverizer in mind, the problem of the present invention is that it is possible to process a slurry with high viscosity, suppress the tendency of the medium to be pressed to the outlet side, increase the internal pressure of the vessel and generate heat. It is an object of the present invention to provide a medium agitation type pulverizer that does not cause problems.

  In order to solve the above-mentioned problems, a medium agitation type pulverizer according to the present invention includes a hollow cylindrical vessel having a slurry inlet at one end and a slurry outlet at the other end, and is coaxially and rotatably disposed inside the vessel. And a driving means for rotationally driving the stirring member. The stirring member includes a rotor having a cylindrical surface, and a plurality of stirring pins arranged at intervals in both the axial direction and the circumferential direction so as to protrude in the radial direction of the cylindrical surface of the rotor. On the inner surface of the vessel, a plurality of stationary pins are arranged at intervals in the radial direction so as to protrude radially inward at positions between the stirring pins of the stirring member when viewed in the axial direction. The grinding chamber formed between the inner surface of the vessel and the cylindrical surface of the rotor of the stirring member is filled with a grinding medium, and the slurry containing the material to be ground is provided while rotating the stirring shaft to provide a circulating motion to the grinding medium. By being introduced into the pulverization chamber, the object to be crushed in the slurry is pulverized into fine particles.

  As a feature of the present invention, the rotor of the stirring member has a groove whose width measured in the axial direction of the rotor is at least twice the diameter of the stationary pin on the cylindrical surface facing the stationary pin protruding from the vessel. Formed opposite each of the rows. By providing this groove, the grinding medium is caused to move radially outward due to the centrifugal force received from the side wall of the groove. Further, in a region in the vicinity of the stationary pin at the radially outer position, that is, the stationary region, a circular motion that moves inward in the radial direction is generated. As a result, the grinding media produces a circular motion that moves radially outward along the sidewalls of the groove and moves radially inward along the stationary pin toward the groove. Therefore, the momentum of the grinding medium is increased even in the region that is normally in the vicinity of the stationary pin, and the amount of slurry transferred by transfer increases. Furthermore, since the cross-sectional area through which the slurry can pass increases, the passage resistance of the slurry decreases, and the pressure loss near the stationary pin decreases. This results in increased grinding throughput and allows processing of high viscosity slurries.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a medium circulation type grinding apparatus according to an embodiment of the present invention, and FIG. 2 is a transverse sectional view taken along the line AA. The pulverizing apparatus 1 includes a cylindrical vessel 2 having one end closed by an end plate 3 and an other end plate 4 having a slurry outlet hole 4a in the center. A slurry inlet 5 is formed near the end of the vessel 2 on the end plate side. A slurry outlet chamber housing 6 is fixed to the outside of the end plate 4, and a slurry outlet chamber 6a communicating with the slurry outlet hole 4a is formed inside. The slurry outlet housing 6 has a slurry outlet 6b.

  A rotor 8 attached to the stirring shaft 7 is disposed inside the vessel 2 so as to extend coaxially in the axial direction. The rotor 8 has a cylindrical surface 8a, and agitation pins 9 extending radially outward are implanted in the cylindrical surface 8a at equal intervals in the axial direction. A plurality of stirring pins 9 are arranged at equal intervals in the circumferential direction at the axial position where the stirring shaft pin 9 is attached. The rotor 8 and the stirring pin 9 constitute a stirring member. The stirring shaft 7 to which the rotor 8 is attached extends outward through the end plate 4 and the outlet housing 6, and is rotatably supported by a bearing housing 10 fixed to the outlet housing 6. A driving pulley 11 driven by a driving device (not shown) via a belt is fixed to an end of the stirring shaft 7 extending outward from the bearing housing 10.

  A crushing chamber 12 is formed inside the vessel 2 between the inner wall surface of the vessel 2 and the cylindrical surface 8 a of the rotor 8. On the inner wall surface of the vessel 2, a plurality of stationary pins 13 are planted at intervals in the circumferential direction at positions alternately in the axial direction with respect to the stirring pin 9 on the rotor 8. The grinding chamber 12 is filled with a number of grinding media 14. A separator 15 is attached to the stirring shaft 7 at a position adjacent to the slurry outlet hole 4 a of the end plate 4 in the grinding chamber 12. The separator 15 forms a gap between the end plate 4 and the grinding medium 14 cannot pass through, and separates the grinding medium 14 from the slurry exiting the outlet hole 4a. The mechanism for separating the pulverizing medium 14 from the slurry is not limited to such a slit method, and other known means such as a screen may be employed.

  In the pulverizing apparatus 1, the stirring member is rotationally driven while introducing the slurry containing the solid material to be pulverized into the pulverizing chamber 12 from the slurry inlet 5. The grinding medium 14 in the grinding chamber 12 is moved by the stirring action of the stirring pin 9, and the solid material to be ground in the slurry is ground or dispersed into fine particles as described above. However, as described above, in this type of pulverizer, there is a problem in the processing of a highly viscous slurry.

  In order to deal with this problem, in the illustrated embodiment of the present invention, the cylindrical surface 8a of the rotor 8 is positioned on the cylindrical surface 8a at a position corresponding to the stationary pin 13, that is, a position facing the tip of the stationary pin 13. In addition, a plurality of circumferential grooves 16 are formed. The width, or axial dimension, of the groove 16 is at least twice the diameter of the stationary pin 13. In a preferred embodiment, the width of the groove 16 is 3 ± 0.5 times the diameter of the stationary pin 13. The depth of the groove 16 is at least 30% of the length of the stationary pin 13. In a preferred embodiment, the depth of the groove 16 ranges from 30% to 60% of the length of the stationary pin 13, and in a more preferred embodiment, it ranges from 45% to 55% of the length of the stationary pin 13.

  In this embodiment of the present invention, the groove 16 having the above-mentioned width is formed in the cylindrical surface 8a of the rotor 8, so that the grinding medium 14 in the grinding chamber 12 has a circumferential groove 16 as shown in FIG. In the vicinity of the side wall 16a, a rotational motion is generated by the action given from the side wall 16a and the action given from the stirring pin 9, and moves outward in the radial direction by centrifugal force. Further, since the rotational motion is suppressed in the stationary region near the stationary pin 13, the centrifugal force is weakened, and the grinding medium 14 moves inward in the radial direction. As described above, the grinding medium 14 generates a circular motion by a radially outward motion from the inside of the groove 16 along the side wall 16a and a radially inward motion from the vicinity of the stationary pin 13. As a result, the transfer amount by transfer in the pulverizing medium 14 is increased, and the passage resistance of the slurry is reduced, so that the processing amount is greatly increased overall.

  A pulverizer was prepared in which a rotor having an outer diameter of 125 mm was disposed in a cylindrical vessel having an inner diameter of 230 mm and a length of 500 mm, and the rotor was rotatably supported by a stirring shaft. The rotor was provided with agitation pins at seven locations at 60 mm intervals in the axial direction and at six locations at equal intervals in the circumferential direction. The stirring pin had a diameter of 10 mm and a length of 30 mm. In the vessel, six stationary pins were arranged at equal intervals in the circumferential direction at a central position between each stirring pin row and the stirring pin row on the rotor. The stationary pin had a diameter of 10 mm and a length of 30 mm.

  There were prepared a crushing device in which a circumferential groove was not formed on the cylindrical surface of the rotor and several types of crushing devices in which circumferential grooves of different sizes were formed. The circumferential groove has a width of 30 mm and a depth of 7.5 mm, 15 mm, and 22.5 mm. Using these pulverizers, the slurry discharge temperature was maintained at a constant 60 ° C., and the slurry discharge amount was measured for slurries having a viscosity of 30000 CP and 60000 CP. The result is shown in FIG. As can be seen from FIG. 4, when the groove depth is around 30% of the length of the stationary pin, the slurry discharge amount starts to increase rapidly, and the increasing tendency is until the groove depth reaches around 60% of the length of the stationary pin. Continue.

  FIG. 5 shows a change in the slurry discharge amount with respect to the increase amount of the grinding medium. As can be seen from this figure, when the groove depth is about 50% of the length of the stationary pin, the slurry discharge amount per unit amount of the grinding medium is maximized. A preferred range is 30% to 60% of the length of the stationary pin, and a more preferred range is 45% to 55% of the length of the stationary pin 13.

  As mentioned above, although this invention was demonstrated about preferable embodiment, this invention is not limited to the detail of this embodiment.

It is a longitudinal cross-sectional view which shows the medium stirring type grinding | pulverization apparatus by one Embodiment of this invention. It is a cross-sectional view in the AA line of FIG. FIG. 2 is an enlarged partial cross-sectional view illustrating a part of the structure of FIG. 1 in order to explain the operation of the present invention. It is a graph which shows the relationship between the depth of a groove | channel and the slurry discharge amount in the Example of this invention. It is a graph which shows the relationship between the depth of the groove | channel in the Example of this invention, and the slurry discharge amount per pulverization medium unit amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crusher 2 ... Vessel 5 ... Slurry inlet 6b ... Slurry outlet 8 ... Rotor 9 ... Stirring pin 12 ... Crushing chamber 13 ... Static pin 14 ... Grinding media

Claims (3)

A hollow cylindrical vessel having a slurry inlet on one end and a slurry outlet on the other end;
A stirring member disposed coaxially and rotatably within the vessel;
Drive means for rotationally driving the stirring member;
With
The stirring member includes a rotor having a cylindrical surface, and a plurality of stirring pins arranged at intervals in both the axial direction and the circumferential direction so as to protrude radially from the cylindrical surface of the rotor,
On the inner surface of the vessel, a plurality of stationary pins are arranged at intervals in the radial direction so as to protrude radially inward at a position between the stirring pins of the stirring member when viewed in the axial direction.
A grinding chamber formed between the inner surface of the vessel and the cylindrical surface of the rotor of the stirring member is filled with a grinding medium, and the object to be ground is rotated while the stirring shaft is driven to circulate the grinding medium. A medium circulation type pulverizing apparatus adapted to pulverize the object to be crushed into fine particles by introducing the slurry containing
In the rotor of the stirring member, a groove whose width measured in the axial direction of the rotor is at least twice the diameter of the stationary pin is formed in a cylindrical surface facing the stationary pin protruding from the vessel in the axial direction of the stationary pin. Formed opposite each of the rows, whereby the grinding media is moved radially outward by centrifugal force received from the groove sidewalls, and radially inward in a region near the stationary pin at a radially outward position To produce a circular movement to move to,
A medium circulation type pulverizer characterized by the above.   2. The crushing apparatus according to claim 1, wherein the width of the groove formed in the rotor is 3 ± 0.5 times the diameter of the stationary pin.   3. The crushing apparatus according to claim 1, wherein a depth of the groove formed in the rotor from the cylindrical surface is 50 ± 10% of a length of the stationary pin. Crushing equipment.

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