JP2015182068A - mixer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new and improved mixer capable of restraining staying of a granule, while maintaining a space factor of the granule in the mixer in a predetermined value or more.SOLUTION: For solving the problem, according to a certain viewpoint of the present invention, a mixer is provided with a mixer body for carrying while agitating a granule in the lateral direction, a gate part provided on a downstream side end surface of the mixer body, maintaining a space factor of the granule in the mixer body in a predetermined value or more and capable of discharging the granule from above an upper end part and one or a plurality of through-holes provided upward from the lower end of the gate part so as to cut out and discharging the granule to an external part of the mixer body, and a height and a width of the respective through-holes are larger than 2.5 times of a maximum pseudo particle diameter of the granule, and the total cross-sectional area of the whole through-holes is smaller than the cross-sectional area in the downstream side end surface of a space factor part of the granule.

Description

  The present invention relates to a mixer.

  As a device for moving the powder body in the lateral direction while kneading, for example, a kneader disclosed in Patent Documents 1 to 3 is known. In the technique disclosed in Patent Document 1, the inside of the kneader is divided into a mixing zone and a granulation zone, and a partition wall is provided at the boundary between the mixing zone and the granulation zone. The partition wall is provided with a through hole whose opening area can be adjusted. In the technique disclosed in Patent Document 1, the residence time of the granular material in the mixing zone is adjusted by adjusting the opening area of the passage hole.

  In the technique disclosed in Patent Document 2, the inside of the kneader is divided into a plurality of zones, and a partition plate is provided at the boundary of each zone. The partition plate is provided with through holes for adjusting the space factor (filling rate) in each zone. In the technique disclosed in Patent Document 3, a movable weir is provided for adjusting the space factor of the granular material in the kneader.

JP 2002-153744 A JP 2011-235258 A Japanese Patent Laid-Open No. 9-313910

  By the way, as a technique for adjusting the space factor of the granular material in the kneader to a predetermined value or more, a technique of providing a weir part (for example, a weir plate) at the tip of the kneader has been proposed. In this technique, a discharge port for the granular material is formed at the upper end portion of the barrier plate. The kneading machine discharges the powder particles from the discharge port by lifting the powder particles near the discharge port to the discharge port. Therefore, with this technique, the kneader becomes an overflow type.

  In this technology, the space factor of the granular material is adjusted to a predetermined value or higher (in other words, the powder surface level of the granular material is adjusted to a predetermined level or higher), so that mixing failure of the granular material is suppressed. can do. For example, when a kneading machine produces a granulated product (pseudo particles) of pulverized coal by kneading pulverized coal and a binder (for example, tar), the kneader can sufficiently knead the pulverized coal and the binder. The quality (yield, etc.) of the granulated product can be improved. In particular, when the input amount (input speed) of pulverized coal is small, insufficient dispersion of the binder is likely to occur, but such insufficient dispersion is suppressed by increasing the space factor.

  However, such a kneader has a problem that the powder particles are agglomerated in the kneader immediately after the kneader is operated and stay in the kneader. In particular, when the kneader has a return blade, a large lump of powder (powder having a particle diameter of about 50 to 150 mm) may stay not only at the tip of the kneader but also around the middle portion. It was. If large lumps stay in the kneader, the kneader cannot be operated continuously. On the other hand, since Patent Documents 1 to 3 do not provide a weir at the tip of the kneader, this problem cannot be solved at all.

  Then, this invention is made | formed in view of the said problem, and the place made into the objective of this invention is maintaining the space factor of the granular material in a mixer more than predetermined value, and of a granular material. It is an object of the present invention to provide a new and improved mixer capable of suppressing stagnation.

  In order to solve the above problems, according to an aspect of the present invention, a mixer main body that conveys powder particles in a lateral direction while stirring, and a downstream end face of the mixer main body, While maintaining the space factor of the granular material above a predetermined value, the weir is capable of discharging the granular material from above, and is provided so as to be cut out upward from the lower end of the weir part. One or a plurality of through holes to be discharged to the outside of the main body, and the height and width of each through hole is larger than 2.5 times the maximum pseudo particle diameter of the granular material, and the total cross-sectional area of all the through holes Is smaller than the cross-sectional area at the downstream end face of the occupied portion of the granular material.

  Here, you may provide the binder injection | throwing-in part which inputs a binder in the mixer main body.

  The granular material may be pulverized coal.

  As described above, according to the present invention, since the through hole satisfying the above dimensional condition is formed in the weir part, the granular material while maintaining the space factor of the granular material in the mixer at a predetermined value or more. Can be suppressed.

It is a sectional side view which shows the structure of the mixer which concerns on embodiment of this invention. It is a plane sectional view showing the composition of the mixer concerning the embodiment. It is a side view which shows the structure of the downstream end surface of a mixer.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. Overall configuration of mixer>
First, based on FIGS. 1-3, the whole structure of the mixer which concerns on embodiment of this invention is demonstrated.

  As shown in FIGS. 1 and 3, the mixer includes a mixer main body 10, a weir portion 60, a discharge port 65, a hopper 70, and a through hole 80.

  The hopper 70 is provided at the upper end of the mixer main body 10 on the upstream end face 20 a side, and supplies the powder X to the mixer main body 10. Here, the type of the powder X is not particularly limited, and may be any as long as it can be transported by the conventional mixer main body. The powder X may be a mixture of a plurality of types of raw materials or a single type of raw materials. The granular material X is pulverized coal, for example. The particle diameter of pulverized coal may be 0.5 mm or less, for example.

  The mixer main body 10 schematically conveys the powder X supplied from the hopper 70 and the binder supplied from the binder inlet 21 in the lateral direction while kneading. And the mixer main body 10 discharges | emits the granular material X by making the granular material X of the dam part 60 vicinity overflow from the discharge port 65 provided above the dam part 60 (overflow). Here, the horizontal direction means a direction other than the vertical direction. The horizontal direction is the horizontal direction (arrow Y1 direction) as shown in FIG. 1, for example, but may be inclined from the horizontal direction to the vertical direction.

  Specifically, the mixer main body 10 includes a housing 20, a binder charging unit 21, a mixing unit 30, and a driving device 40. The housing 20 has a cylindrical shape and incorporates a mixing unit 30. That is, the housing 20 becomes an outer wall of the mixer main body 10. The upstream end face 20a of the housing 20 is closed, and the downstream end face 20b is partially closed by a dam 60 described later.

  The binder loading unit 21 is for loading the binder into the mixer main body 10, specifically, into the housing 20. The binder charging unit 21 may not be provided. When the mixer has a binder charging part 21, the mixer is also referred to as a kneader. The kind of binder should just be selected arbitrarily by the use of a mixer. For example, when the mixer is a kneader for kneading pulverized coal, the binder is tar. The mixer produces a granulated product (pseudo particles) of pulverized coal by kneading pulverized coal and tar, and discharges the granulated product of pulverized coal from the discharge port 65. The granulated product of pulverized coal can be agglomerated by being agglomerated by an agglomerator. In addition, when a mixer does not have the binder insertion port 21, a mixer will convey the granule X in a horizontal direction, mixing.

  The mixing unit 30 includes a shaft body 31 and a blade portion 32. As shown in FIG. 2, in this embodiment, two mixing portions 30 are arranged in parallel in the housing 20. Of course, the number of the mixing parts 30 is not limited to this example.

  The shaft body 31 has a long cylindrical shape and is disposed in the housing 20 so as to be parallel to the length direction of the housing 20. The shaft body 31 is rotated in the arrow Y2 direction by the driving force supplied from the driving device 40. A straight line 31 a indicates the rotation axis of the shaft body 31. The front end portion of the shaft body 31 extends through the weir portion 60 to the outside of the mixer main body 10, and the rear end portion extends through the upstream end surface 20 a of the housing 20 to the outside. The rear end portion of the shaft body 31 is connected to the drive device 40.

  The blade portion 32 is provided in a spiral shape on the peripheral surface of the shaft body 31. Therefore, the mixer is a so-called screw conveyor. The blade portion 32 rotates integrally with the shaft body 31. The blade portion 32 rotates integrally with the shaft body 31 to convey the powder X in the housing 20 to the vicinity of the opening 50 while being kneaded with the binder (that is, conveyed in the direction of arrow Y1). Then, the mixing unit 30 causes the powder X near the opening 50 to overflow from the discharge port 65 above the weir unit 60.

  The blade portion 32 can take various forms depending on the application of the mixer and the like. For example, when the mixer needs to sufficiently knead the powder X and the binder, a part of the blade portion 32 becomes a return blade. The return blade returns the granular material X in the direction opposite to the arrow Y1. When the blade portion 32 has a return blade, the blade portion 32 finally transports the granular material X1 to the discharge port 65 while reciprocating in the mixer main body 10. Thereby, the granular material X is sufficiently kneaded in the mixer main body 10. In FIG. 1, the blade pitch just below the hopper 70 is narrower than the blade pitch in other regions, but the blade pitch is not limited to this example. For example, the blade pitch may be the same in the entire region within the housing 20, or may gradually increase toward the downstream end surface 20b. Further, the shape of the blade portion 32 is not limited to the screw shape. For example, the blade portion 32 may have a paddle shape. In this case, the blade portion 32 extends radially from the shaft body 31. Moreover, when the blade | wing part 32 becomes a paddle shape, the mixer main body 10 becomes what is called a paddle type mixer. In the examples described later, the effect of the present invention is verified using a paddle type mixer.

  The weir unit 60 is provided on the downstream end surface 20 b of the mixer main body 10. The weir part 60 keeps the space factor of the granular material X in the mixer main body 10 at a predetermined value or more by closing most of the downstream end face 20b. Furthermore, a discharge port 65 is formed above the weir unit 60, and the granular material X is discharged from the discharge port 65 to the outside. Here, the space factor is also referred to as a filling rate. Of the hollow portion of the mixer main body 10 (the portion excluding the portion of the hollow portion of the housing 20 that is closed by the mixing portion 30), the powder X is It means the ratio of occupied part. The space factor is the upper end height H of the weir unit 60 (see FIG. 3), the input amount of the granular material X supplied from the hopper 70 to the mixer main body 10 per unit time (that is, the input speed), and the mixing unit 30. , The volume of the hollow portion of the mixer body 10, the total cross-sectional area of all the through holes 80, and the like. Therefore, the user of the mixer can adjust the space factor to a desired value by arbitrarily adjusting these parameters. Here, the upper end height H of the weir unit 60 means the height from the rotation axis (straight line 31 a) of the shaft body 31 to the upper end surface of the weir unit 60 as shown in FIGS. 1 and 3.

  As shown in FIG. 3, the through hole 80 is provided so as to be cut out upward from the lower end of the dam portion 60. Specifically, the through hole 80 is provided at a position facing each mixing unit 30. More specifically, the through hole 80 is provided at a position facing the lowest point of the blade portion 32. The through hole 80 discharges the granular material X present at the lower end of the downstream end face 20b to the outside. Thereby, the residence in the mixer main body 10 of the granular material X can be suppressed. Of course, as long as the through-hole 80 is provided so as to be cut out upward from the lower end of the weir part 60, it may be provided in a place other than the above, but the above arrangement is most preferable.

  The cross section of the through hole 80 is rectangular. The width L1 and the height L2 of the through-hole 80 are both larger than 2.5 times the maximum pseudo particle diameter of the granular material X. Preferably, the width L1 and the height L2 of the through-hole 80 are both larger than 3.0 times the maximum pseudo particle diameter of the granular material X. Here, the cross section of the occupied portion of the discharge port 65, the through hole 80 and the granular material X means a cross section perpendicular to the length direction of the mixer main body 10. The width L1 is a dimension in the width direction of the through hole 80 (a direction perpendicular to the paper surface of FIG. 1), and the height L2 is a dimension in the vertical direction of the through hole 80. The maximum pseudo particle size of the granular material X is the particle size of the largest of the granulated materials (pseudo particles) of the granular material X discharged from the mixer body 10. The pseudo particle size is measured using, for example, sieves having different mesh sizes. For example, a sieve having an aperture of 0.3 mm is prepared, and the granulated material to be measured is passed through this sieve. The granulated product remaining on the sieve has a pseudo particle diameter larger than 0.3 mm, and the granulated product dropped from the sieve has a pseudo particle diameter of 0.3 mm or less. The particle diameter of other particles is also measured by the same method. The maximum pseudo particle size may be confirmed by actually operating the mixer main body 10. Since the width L1 and the height L2 of the through hole 80 have the above-described sizes, the powder X and the granulated product are less likely to be clogged in the through hole 80.

  Moreover, the total cross-sectional area of all the through-holes 80 is smaller than the cross-sectional area in the downstream end surface 20b of the occupied part of the granular material X. FIG. Here, the cross-sectional area at the downstream end face 20b of the powder X may be measured as follows, for example. That is, the mixer main body 10 is driven with the dam portion 60 removed. And the mixer main body 10 is stopped at the timing when the space factor of the granular material X becomes substantially constant. At this time, the granular material X is also occupied on the downstream end face 20b. And the cross-sectional area in the downstream end surface 20b of the occupied part of the granular material X is measured. Therefore, the cross-sectional area at the downstream end face 20b of the occupied portion of the granular material X is the operating condition (for example, the particle size distribution of the granular material X, the granular material X charged into the mixer main body 10 per unit time). Depending on the amount of input etc.). For this reason, the total cross-sectional area of the through hole 80 may be variable. Alternatively, a plurality of types of dam portions 60 having different total cross-sectional areas of the through holes 80 may be prepared, and the dam portions 60 may be selected according to operating conditions.

  The cross-sectional shape of the through hole 80 is not limited to a rectangle, and may be a circle, for example. In this case, the diameter of the cross section may be 2.5 times or more of the maximum pseudo particle diameter, and the total cross sectional area may be set so as to satisfy the above conditions. Moreover, although it is preferable that each through-hole 80 is the same shape and magnitude | size, it does not necessarily need to be the same.

<2. Operation of mixer>
Next, the operation of the mixer will be described. While the granular material X and the binder are charged into the mixer at a predetermined charging speed, the shaft body 31 is driven by the driving device 40. Thereby, the granular material X in the mixer moves in the arrow Y1 direction while being stirred (kneaded) by the mixing unit 30. After moving to the vicinity of the dam portion 60, the powder X is lifted by the mixing portion 30 and discharged from the discharge port 65. On the other hand, the space factor of the granular material X is maintained at a predetermined value or more by the weir part 60. Further, a part of the granular material X is discharged from the through hole 80 to the outside. Thereby, the residence in the mixer of the powder body X is suppressed and by extension, generation | occurrence | production of a large lump is suppressed.

Example 1
Next, Example 1 of the present embodiment will be described. In Example 1, the granular material X was pulverized coal (particle diameter of 0.5 mm or less), and the binder was tar. The mixer was a two-shaft paddle mixer (a paddle mixer having two shaft bodies 31). Moreover, the blade | wing part 32 used the thing with a return blade | wing, and the diameter of the blade | wing part 32 was 880 mm. The length of the mixer was 4600 mm.

  And the dam part 60 was installed in the downstream end surface 20b, and the shaft 31 was rotated at 27 rpm. On the other hand, pulverized coal was charged into the mixer at 30 t / h, and tar was charged into the mixer at 3 t / h (10% by mass of pulverized coal). And the upper end height H of the weir part 60 was adjusted to 240 mm so that the space factor at this time might be 55%.

Next, the weir unit 60 was removed, and the mixer was driven under the same operating conditions. The mixer was stopped at the timing when the pulverized coal space factor became substantially constant, and the cross-sectional area at the downstream end face 20b of the occupied portion of the pulverized coal was measured. As a result, the cross-sectional area of the occupied portion was 0.1 m ² . The maximum pseudo particle size was 15 mm. Therefore, 2.5 times the maximum pseudo particle size is 37.5 mm.

Next, a through hole 80 having a width of 300 mm and a height of 40 mm is provided so as to cut out upward from a position facing the lowest point of each mixing unit 30 in the lower end portion of the weir unit 60, and the weir unit 60 is again mixed with the mixer. Installed on the downstream end face 20b. Therefore, the total cross-sectional area of all the through holes 80 is 0.024 m ² . Further, the height of the through hole 80 is larger than 2.5 times the maximum pseudo particle diameter and smaller than 3 times. And the mixer was driven on the same operation conditions as the above. As a result, even if the operation was continued for one month, the mass was hardly deposited and the space factor was able to maintain the above value.

(Example 2)
The same processing as in Example 1 was performed except that the dimensions of each through hole 80 were set to be 300 mm in width and 50 mm in height. In Example 2, the height is greater than 3.0 times the maximum pseudo particle size. As a result, even if the operation was continued for one month, no large mass was deposited, and the space factor was able to maintain the above value. That is, it was possible to suppress the generation of large lumps than Example 1. The reason for this is considered to be that the pulverized coal does not stay at the bottom of the mixer, and the discharge of the large mass has become smoother.

(Comparative Example 1)
The same processing as in Example 1 was performed except that the dimensions of each through-hole 80 were set to 300 mm width × 30 mm height. In Comparative Example 1, the through-hole 80 was clogged when about 1 day had elapsed from the start of operation, and continuous operation was not possible. In addition, many large lumps stayed in the mixer.

(Comparative Example 2)
The same processing as in Example 1 was performed except that the dimensions of each through hole 80 were set to be 300 mm in width and 200 mm in height. In Comparative Example 2, the total cross-sectional area of all the through holes 80 is 0.12 m ² . In Comparative Example 2, since the space factor could not maintain the above value, continuous operation could not be performed.

(Comparative Example 3)
The same processing as in Example 1 was performed except that the through hole 80 was not provided. In Comparative Example 3, a large amount of large lumps were generated in the mixer just after about 1 day had elapsed since the start of operation. For this reason, continuous operation was not possible.

  According to Examples 1 and 2 and Comparative Examples 1 to 3, by providing the through hole 80 satisfying the above dimensional conditions in the weir part 60, the retention of the granular material while maintaining the space factor at a predetermined value or more. It can be seen that this can be suppressed.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Mixer main body 20 Housing 21 Binder insertion part 30 Mixing part 31 Shaft body 32 Blade | wing part 40 Drive device 60 Weir part 65 Outlet 70 Hopper 80 Through-hole

Claims (3)

A mixer main body for conveying powder particles in a lateral direction while stirring;
A dam part provided on the downstream end face of the mixer main body, maintaining a space factor of the granular material in the mixer main body at a predetermined value or more, and capable of discharging the granular material from above;
One or a plurality of through-holes provided so as to be cut out upward from the lower end of the weir part, and discharging the powder particles to the outside of the mixer main body,
The height and width of each through-hole is larger than 2.5 times the maximum pseudo particle diameter of the granular material, and the total cross-sectional area of all through-holes is at the downstream end face of the occupied portion of the granular material. A mixer characterized by being smaller than the cross-sectional area.   The mixer according to claim 1, further comprising a binder loading unit that loads the binder into the mixer body. The mixer according to claim 1 or 2, wherein the granular material is pulverized coal.

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