CN110662610B

CN110662610B - Powder classifying device and classifying system

Info

Publication number: CN110662610B
Application number: CN201880034777.6A
Authority: CN
Inventors: 谢花一成; 岸田好雄; 三岛刚
Original assignee: Ryux Inc
Current assignee: Ryux Inc
Priority date: 2017-06-01
Filing date: 2018-05-30
Publication date: 2022-05-27
Anticipated expiration: 2038-05-30
Also published as: JP2018202303A; WO2018221584A1; KR20200014781A; KR102395420B1; TWI681823B; JP6262907B1; CN110662610A; TW201906669A

Abstract

The invention provides a classification device and a classification system for simply classifying powder such as fly ash. The classification device has: a raw powder discharging unit (6) that discharges raw powder together with gas; and a suction unit (4) which is disposed opposite to the raw powder discharge unit (6) at a position spaced apart from the raw powder discharge unit (6) and sucks the raw powder and a part of the gas, wherein the raw powder discharge unit (6) includes: a housing section (2) having a swirling section (61) for swirling the raw powder and the gas, housing the raw powder discharge section (6) and the suction section (4) therein, and surrounding the outer periphery thereof; and a delivery pipe for delivering the raw powder and the gas, which has an inlet for taking in the raw powder below the storage unit (2) together with the gas, and which delivers the raw powder and the gas taken in from the inlet to the raw powder delivery unit (6).

Description

Powder classifying device and classifying system

Technical Field

The present invention relates to a powder classifying device and a classifying system.

Background

Conventionally, a classifying device for classifying a powder into particles having a size according to the application has been proposed.

As one of such classifying devices, a classifier that performs classification by using centrifugal force generated by rotation of a classifying rotor has been proposed (see patent document 1). The classifier is configured such that the introduction direction of the classifying air is opposite to the conventional direction with respect to the rotation direction of the classifying rotor. This makes it possible to obtain a large separating force by applying a rapid change in the flow direction to the inlet of the rotating blade of the classifying rotor, and to perform classification with higher accuracy at a smaller number of revolutions.

Further, a classifier has been proposed which classifies a component supplied to the outer side of a classifying rotor by guiding the powder to the inner side of the classifying rotor based on the relationship between a centrifugal force and a centripetal force (see patent document 2). The classifier is characterized in that each rotating blade of the classifying rotor is arranged in a state of being inclined with respect to the supporting member so that one supporting member side is closer to the rotating direction than the other supporting member side. This can improve the separation performance without increasing the rotational speed of the classifying rotor.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2001-353473

Patent document 2: japanese patent laid-open No. 2005-342556

Disclosure of Invention

Problems to be solved by the invention

However, in the classifier using the classifying rotor, in order to ensure the classifying performance, mechanical strength and driving power for rotating the classifying roller at a certain number of revolutions are required.

The present invention has been made in view of the above problems, and an object thereof is to provide a classifying device and a classifying system for classifying powder with high accuracy by a simple configuration.

Means for solving the problems

The classification device of the present invention is characterized by comprising: a raw powder supply pipe for carrying and transporting raw powder in an air flow; a raw powder discharging unit connected to an upper portion of the raw powder supply pipe for the treatment, and configured to discharge the raw powder together with a gas from an upper surface of the opening; a suction unit that is disposed opposite to an upper surface of the opening of the raw powder discharge unit at a position spaced apart from the raw powder discharge unit, and sucks the raw powder and a part of the gas from a lower surface of the opening; and a housing portion that houses the raw powder discharging portion and the suction portion therein and surrounds an outer periphery thereof, and deposits the raw powder during classification or after classification processing, wherein the raw powder discharging portion has a swirling portion having a fixed blade inclined in a circumferential direction therein, the raw powder supplied from the raw powder supply pipe during processing is swirled together with the gas by the swirling portion, and discharged radially from an upper surface of the opening in a swirling state, and the suction portion is configured to suck the raw powder that travels while being swirled while being discharged radially from the upper surface of the opening of the raw powder discharging portion.

Effects of the invention

According to the present invention, a classification device and a classification system for classifying powder with high accuracy by a simple configuration can be provided.

Drawings

Fig. 1 is an explanatory diagram showing a configuration of a hierarchical system.

Fig. 2 is an explanatory diagram schematically showing the structure of the classifying device.

Fig. 3 is an explanatory view for explaining a structure in the vicinity of the raw powder discharging portion of the classifying device.

Fig. 4 is an explanatory view for explaining the operation at the time of raw powder supply and at the time of pulverization and classification.

Fig. 5 is an explanatory view schematically showing a classification in crushing classification in a case where the position of the suction portion is changed.

Detailed Description

An embodiment of the present invention will be described below with reference to the drawings.

Examples

< grading System >

Fig. 1 is an explanatory diagram showing the structure of the hierarchical system 100.

The classification system 100 includes: a raw powder silo 11 that stores raw powder of fly ash; a classifying device 1 for classifying the raw powder; a raw powder conveying mechanism 14 having a bag filter 12 for filtering and collecting fine powder classified from raw powder, and conveying the raw powder in the raw powder bin 11 to the classifying device 1 while carrying the raw powder in an air flow; a fine powder conveying pipe 5a connecting the classifying device 1 and the bag filter 12; and a fine powder conveying mechanism 15 for conveying the fine powder collected by the bag filter 12 to a product bin (not shown).

The raw powder conveying mechanism 14 includes: a rotary feeder 14a having an IN side connected to the bottom 11a of the raw powder bin 11; an acceleration pipe 14b connected to the OUT side of the rotary feeder 14 a; and a roots blower 13. The IN side of the acceleration pipe 14b is connected to the roots blower 13 via a pipe 13a provided with an air valve 14c IN the middle, and the OUT side is connected to the classifying device 1 via a raw powder supply pipe 14 d.

The raw powder conveying mechanism 14 operates as follows. First, the rotary feeder 14a is started to supply the raw powder quantitatively from the raw powder bin 11 to the acceleration pipe 14 b. Next, the air valve 14c is switched to the open state, and compressed air is sent from the roots blower 13 to the IN side of the acceleration pipe 14b through the pipe 13 a. The air supply is not limited to compressed air, and may be compressed air in which an appropriate gas such as nitrogen is compressed. In the acceleration tube 14b, the compressed air accelerates the flow velocity, and disperses and floats the raw powder in the acceleration tube 14 b. Then, the raw powder is discharged from the OUT side of the acceleration pipe 14b by the airflow, and is conveyed to the classifier 1 through the raw powder supply pipe 14 d.

The classifying device 1 classifies the raw powder. Further, the details of the operation will be described later. As shown in the figure, 2 or more classifying devices 1 may be provided in series, thereby achieving higher-performance classification.

The fine powder classified by the classifier 1 is carried by the fine powder carrying pipe 5a along with the air flow, and is carried to the bag filter 12.

The bag filter 12 has: a filter cloth 12b for filtering and collecting the fine powder from the air flow accompanied by the fine powder; and a hopper 12c for collecting the fine powder brushed off from the filter cloth 12 b.

The fine powder conveying mechanism 15 includes: a rotary feeder 15a having an IN side connected to the bottom 12a of the hopper 12 c; an acceleration pipe 15b connected to the OUT side of the rotary feeder 15 a; and a roots blower 13. The IN side of the acceleration pipe 15b is connected to the roots blower 13 via a pipe 13c provided with an air valve 15c IN the middle, and the OUT side is connected to a product bin (not shown) via a fine powder collection pipe 15 d.

The fine powder conveying mechanism 15 operates in the same manner as the raw powder conveying mechanism 14 described above. That is, the rotary feeder 15a is started to supply the fine powder quantitatively from the hopper 12c to the acceleration pipe 15 b. Next, the air valve 15c is switched to the open state, and compressed air is sent from the roots blower 13 to the IN side of the acceleration pipe 15b through the pipe 13 c. In the acceleration pipe 15b, the compressed air accelerates the flow velocity, and the fine powder in the acceleration pipe 15b is dispersed and floated. Then, the fine powder is discharged from the OUT side of the acceleration pipe 15b by the airflow, passes through the fine powder collection pipe 15d, and is conveyed to a product bin (not shown).

< fractionating apparatus >

Fig. 2 is an explanatory view schematically showing the structure of the classifying device 1, fig. 3(a) is a cross-sectional view a-a of the classifying device, fig. 3(B) is a vertical cross-sectional view of the raw powder discharging unit 6 of the classifying device 1, and fig. 3(C) is a perspective view of a cross-section B-B of the classifying device 1.

The classification device 1 includes: a raw powder discharging unit 6 that discharges raw powder together with air; a suction part 4 which is disposed opposite to the raw powder discharge part 6 at a position spaced apart from the raw powder discharge part 6 and sucks part of the raw powder discharged by the raw powder discharge part 6 and air; a housing section 2 that houses the raw powder discharge section 6 and the suction section 4 therein and surrounds the outer periphery; and a processed raw powder conveying mechanism 7 for conveying the raw powder accumulated in the bottom 22 of the storage part 2 during or after the classification processing.

The raw powder discharging part 6 is substantially cylindrical with a center line facing the vertical direction, has a substantially horizontal upper surface and a substantially circular opening 62, and has a swirling part 61 for swirling the raw powder and air therein. With this configuration, the raw powder and air supplied from below are rotated clockwise in a plan view by the swirling portion 61, and are radially discharged from the upper opening 62.

The raw powder discharger 6 is provided above the center of the internal space of the container 2, and in this embodiment, is provided slightly above the center. This allows a large amount of raw powder to be accumulated in the area of the internal space of the housing 2 below the raw powder discharger 6, and allows the raw powder sucked by the suction unit 4 to be classified in the area above the raw powder discharger 6.

As shown in fig. 3(C), the swirling portion 61 is formed by a plurality of fixed blades 61a, and these fixed blades 61a have centers on a straight line passing through the center of the raw powder discharging portion 6 and the center of the suction portion 4, and are expanded in the radial direction from the centers and inclined in the circumferential direction. In addition, although the above description has been made with the swirl portion 61 formed by 3 fixed blades 61a, there may be a plurality of

fixed blades

61a, and 4, 6, or 8 fixed blades may be used. In addition, the above description has been made of the case where the turning part 61 is formed in a single type by the 3 fixed blades 61a, and may be formed in a multi-stage type (multi-stage type) in which a plurality of groups of the 3 fixed blades 61a are arranged at intervals on the center line.

A cylindrical raw powder supply pipe 73 for processing passing through the center axis of the housing 2 in the vertical direction is connected to the lower side of the raw powder discharging unit 6. In this process, the raw powder supply pipe 73 is formed to have a constant thickness with a radius smaller (i.e., thinner) than that of the raw powder discharging unit 6, and is changed in direction by 90 degrees in the vicinity of the lower portion in the housing unit 2 to protrude outside the housing unit 2, and is further changed in direction downward and connected to the acceleration pipe 72. A switching valve 73a is provided in the middle of the raw powder supply pipe 73 in the process of extending to the outside of the housing section 2.

The suction portion 4 is substantially cylindrical with its center line oriented in the vertical direction, has a substantially horizontal and substantially circular opening 42 in the lower surface, and is disposed above the raw powder discharge portion 6 so as to face the raw powder discharge portion 6. The fine powder discharge pipe 5 for discharging the raw powder sucked into the suction part 4 and a part of the air is connected to the suction part 4 on the side opposite to (i.e., above) the raw powder discharge part 6.

The size of the opening 42 of the suction part 4 is formed to be the same as the size of the opening 62 of the raw powder discharging part 6. The opening of the opening 42 of the suction part 4 may be configured to have a suitable size such as a size larger than the opening 62 of the raw powder discharging part 6 or a size smaller than the opening 62 of the raw powder discharging part 6.

The suction portion 4 is disposed so as to be spaced vertically upward from the raw powder discharging portion 6 such that the central axis of the cylindrical shape (circular opening 42) coincides with the central axis of the cylindrical shape (circular opening 62) of the raw powder discharging portion 6, and the opening 42 of the suction portion 4 faces the opening 62 of the raw powder discharging portion 6. This makes it possible to appropriately adjust the particle size of the raw powder discharged from the raw powder discharge unit 6 and sucked into the suction unit 4.

The fine powder discharge pipe 5 has a lower portion connected to the suction portion 4 in the suction portion 4 and an upper portion disposed outside the suction portion 4, and functions as a discharge pipe for discharging the raw powder and a part of the air classified and replenished in the suction portion 4 to the outside.

The fine powder discharge pipe 5 is composed of a double pipe (an inner pipe and an outer pipe) which is fixed to the housing section 2 and is slidable, and the inner pipe is connected to the suction section 4. The fine powder discharge pipe 5 has a variable position screw 4a, and the variable position screw 4a is a screw screwed into the outer pipe from the outside, and the relative position of the inner pipe and the outer pipe can be changed and fixed by pressing the outer peripheral surface of the inner pipe with the tip of the screw to stop the sliding of the inner pipe. This makes it possible to change and fix the relative positions of the suction portion 4 connected to the inner tube, the housing portion 2 fixed to the outer tube, and the raw powder discharge portion 6 housed inside the housing portion 4. That is, the distance D between the suction portion 4 and the raw powder discharge portion 6 can be changed. The configuration of changing the distance D between the suction unit 4 and the raw powder discharge unit 6 is not limited to this, and may be an appropriate configuration.

The housing 2 is a substantially cylindrical container having a center line oriented in the vertical direction, and is formed in a vertically long shape larger than the radius of the raw powder discharging part 6. The radius of the housing part 2 is preferably 2 times or more, and in the present embodiment, 3 times or so, the radius of the raw powder discharging part 6.

The housing 2 functions as a swirling flow guide wall 21 in which a cylindrical portion flows along a swirling flow on a wall inner surface. The swirling flow guide wall 21 is provided with a supply nozzle 3 (see fig. 3 a) that is arranged in a straight line in a tangential direction of a wall surface in the vicinity of the suction portion 4. The raw powder and air are supplied from the supply nozzle 3 into the housing 2. In this embodiment, the supply nozzle 3 is configured to rotate (swirl) the raw powder and the air flowing into the swirling flow guiding wall 21 in a clockwise direction when viewed from above in the swirling flow guiding wall 21. In this configuration, the rotation direction (swirling direction) in plan view of the raw powder and air supplied from the supply nozzle 3 is aligned with the rotation direction (swirling direction) in plan view of the raw powder and air discharged from the raw powder discharger 6 in the swirling flow guide wall 21.

The processed raw powder conveying mechanism 7 includes: a rotary feeder 71 having an IN side connected to the bottom 22 of the storage section 2; an acceleration pipe 72 connected to the OUT side of the rotary feeder 71; and a roots blower 13 (see fig. 1). The IN side of the acceleration pipe 72 is connected to the roots blower 13 (see fig. 1) via a pipe 13b provided with an air valve 74a IN the middle, and the OUT side is connected to the raw powder supply pipe 73 for processing and the raw powder recovery pipe 75 for processing. The raw powder supply pipe 73 for treatment is provided with a switching valve 73a in the middle and connected to the raw powder emitting unit 6. On the other hand, the treated raw powder recovery pipe 75 is provided with a switching valve 75a in the middle, and is connected to a product bin (not shown).

Classifying action during raw powder supply

Fig. 4(a) is an explanatory view schematically showing the classification when the raw powder is supplied.

When the raw powder conveying mechanism 14 (see fig. 1) is in operation, the raw powder is conveyed to the supply nozzle 3 of the classifier 1 through the raw powder supply pipe 14d together with air. The raw powder is then discharged from the supply nozzle 3 into the housing 2 together with air, flows along the swirling flow guide wall 21, generates a swirling flow, and falls (see fig. 3 a). The swirling flow applies a centrifugal force to the raw powder. At this time, the fine powder FA1 (see fig. 4 a) in the raw powder has a small mass and thus a centrifugal force is weak, and a part of the fine powder FA1 is sucked into the suction portion 4 together with the air from the swirling flow guide wall 21. On the other hand, the surplus raw powder FA2 gradually descends by gravity while swirling along the swirling flow guide wall 21, and is deposited on the bottom 22 of the housing 2 (see fig. 4B). When a predetermined amount of raw powder is supplied into the housing section 2, the raw powder conveying mechanism 14 (see fig. 1) is stopped, and the supply of the raw powder to the classifying device 1 is stopped.

Action for crushing and classifying raw powder in treatment

Fig. 4(B) is an explanatory view schematically showing the crushing and classification of the raw powder during the treatment.

The raw powder conveying mechanism 14 (see fig. 1) is stopped to stop the supply of the raw powder to the classifying device 1, and the raw powder conveying mechanism 7 is operated to start the circulating conveyance of the raw powder processed by classification at the time of supply in the classifying device 1. The stop of the raw powder conveying mechanism 14 and the operation of the processed raw powder conveying mechanism 7 are not limited to being performed simultaneously, and one may be performed first and the other may be performed later. Here, even when there is an instant in which both operations are performed in the order of stopping the raw powder conveying mechanism 14 after the operation of the processed raw powder conveying mechanism 7, the supply and classification of the raw powder can be appropriately performed, respectively. That is, since the supply nozzle 3 is provided at a position shifted from the discharge direction of the raw powder and the air from the supply nozzle 3, most of the raw powder supplied from the supply nozzle 3 drops and is not sucked into the suction portion 4. Since only the fine particles sucked into the suction portion 4 after classification are sucked into the suction portion 4, the classification performance is not affected.

First, the rotary feeder 71 is started to quantitatively supply the raw powder being processed, which is deposited on the bottom 22 of the storage section 2, to the acceleration pipe 72. Next, the air valve 74a is switched to the open state (see fig. 2), and compressed air is sent from the roots blower 13 (see fig. 1) to the IN side of the acceleration pipe 72 through the pipe 13 b. The air blow is not limited to compressed air, and may be compressed air in which a gas such as nitrogen is compressed. In the acceleration pipe 72, the flow velocity is accelerated by the compressed air, and the raw powder in the acceleration pipe 72 is dispersed and floated. The raw powder is discharged from the OUT side of the acceleration tube 72 by the airflow. At this time, the switching valve 73a provided in the raw powder supply pipe 73 for the process is switched to the open state, and the switching valve 75a provided in the raw powder recovery pipe 75 for the process is switched to the closed state. Thus, the raw powder is carried by the air flow and transported to the raw powder discharging unit 6 through the raw powder supply pipe 73 during the processing.

The raw powder conveyed to the raw powder discharger 6 contains fine powder and coarse powder remaining without being sucked into the suction unit 4 in the classification operation at the time of raw powder supply. The fine powder is a particle having a small particle diameter. The coarse powder includes, in addition to particles having a large particle diameter (intrinsic coarse powder), clusters such as coarse powder in which a plurality of particles having a small particle diameter (fine powder) are bonded to each other with a weak bonding force to form a block such as a bunch of grapes, and coarse powder in which a plurality of fine powders are bonded to each other with a weak bonding force around the intrinsic coarse powder to form a block.

The raw powder fed from the raw powder supply pipe 73 to the raw powder discharger 6 is carried upward (vertically upward) in the direction of the center line of the raw powder discharger 6 by the airflow, and collides with the fixed blade 61a forming the swirling portion 61 (see fig. 3B). Due to this collision, the cluster is broken in many cases, and a plurality of individual fine powders are separated. As a result, the raw powder transported to the raw powder discharging unit 6 becomes fine powder newly generated by crushing, clusters remaining without being completely crushed, and intrinsic coarse powder in addition to the remaining fine powder.

The airflow on which these fine particles, clusters, and intrinsic coarse powder are carried becomes a swirling flow swirling around the center line of the raw powder discharging portion 6 and traveling straight in the center line direction by the plurality of fixed blades 61a spreading from the center in the radial direction and inclining in the circumferential direction, and is discharged radially to the upper space from the opening 62 while swirling. The fine powder is hardly affected by the centrifugal force of the swirling flow because of its small mass. Therefore, the fine powder FB1 travels while rotating in the center line direction or in a direction slightly inclined from the center line direction, and is sucked into the suction unit 4 (see fig. 4B). On the other hand, the clusters or the intrinsic coarse powder remaining after the incomplete crushing are subjected to a large centrifugal force due to their large mass. Therefore, the cluster FB2 and the intrinsic coarse powder FB3 travel while rotating in a direction approaching in the radial direction greatly deviating from the center line direction, and then gradually descend by the action of gravity while swirling along the swirling flow guide wall 21, and are again deposited on the bottom portion 22 of the housing 2.

As described above, the remaining fine powder or the fine powder separated by the crushing of the clusters is sucked into the suction part 4, while the clusters or the intrinsic coarse powder are again accumulated on the bottom part 22 of the housing part 2, thereby classifying the raw powder.

The clusters or intrinsic coarse powder accumulated on the bottom 22 of the storage section 2 can be transported to the raw powder discharging section 6 a plurality of times by circulating the clusters or intrinsic coarse powder in the classifying device 1 by continuously operating the raw powder transport mechanism 7. As described above, the clusters transferred to the raw powder discharging portion 6 are crushed to re-separate the fine powder, and become smaller clusters. The fine powder newly separated and the remaining fine powder not sucked are sucked into the suction unit 4. By continuing the operation of the processed raw powder conveying mechanism 7 in this way, the crushing can be repeated a plurality of times until the clusters are no longer clusters, and the processing can be repeated until the fine powder contained in the raw powder is substantially sucked. As a result, most of the fine particles present as clusters are finally separated and sucked and collected by the suction unit 4. Therefore, the recovery rate of the fine powder can be improved.

As described above, the distance between the suction portion 4 and the raw powder discharge portion 6 can be changed by changing the distance of the suction portion 4 using the position-variable screw 4a provided in the fine powder discharge pipe 5. For example, when the position of the suction part 4 is P2 and the distance between the suction part 4 and the raw powder discharge part 6 is D2, not only the fine powder FB1 but also a part of small clusters may be sucked into the suction part 4. However, by setting the position of the inhalation section 4 to P1, the distance between the inhalation section 4 and the raw powder discharge section 6 is increased to D1 (enlarged interval), and only the fine powder FB1 can be inhaled from the inhalation section 4. This improves the accuracy of classification of the fine powder and the other components than the fine powder. By enlarging the distance D between the suction portion 4 and the raw powder discharge portion 6 in this way, only finer fine particles can be sucked by the suction portion 4, and conversely, by narrowing the distance D between the suction portion 4 and the raw powder discharge portion 6, coarser particles can also be sucked by the suction portion 4. Therefore, by adjusting the distance (interval) between the suction part 4 and the raw powder discharge part 6, the maximum particle diameter of the fine powder sucked by the suction part 4 can be adjusted, and the accuracy of classification can be improved.

Operation for recovering raw powder (coarse powder) after treatment

When the processed raw powder (coarse powder) is collected, the processed raw powder conveying mechanism 7 is temporarily stopped, and the circulating supply of the processed raw powder in the classifying device 1 is stopped (see fig. 2). Then, the switching valve 73a provided in the raw powder supply pipe 73 for the process is switched to the closed state, and the switching valve 75a provided in the raw powder recovery pipe 75 for the process is switched to the open state. Then, by operating the processed raw powder conveying mechanism 7 again, the processed raw powder (coarse powder) is carried by the air flow and passed through the processed raw powder recovery pipe 75 to be conveyed to a product bin (not shown).

With the above configuration and operation, the classifying device 1 can classify the powder with high accuracy with a simple configuration.

Specifically, the classifier 1 includes: a raw powder discharging part 6 for discharging the raw powder together with the gas by swirling; and a suction part 4 which is arranged opposite to the raw powder discharge part 6 at a position spaced apart from the raw powder discharge part 6 and sucks a part of the raw powder and the gas, wherein the raw powder discharge part 6 has a swirling part 61 for swirling the raw powder and the gas. Therefore, the raw powder performs a swirling motion in the raw powder discharging unit 6. Thus, the fine powder and the part other than the fine powder which have undergone swirling motion are subjected to centrifugal forces of different magnitudes. The fine powder having a small centrifugal force is absorbed by the suction portion 4, and the suction portion 4 is disposed to face the raw powder discharge portion 6 at a position spaced apart from the raw powder discharge portion 6. Thus, the raw powder can be classified into fine powder and a part other than the fine powder by using the classifying device 1 having a simple structure.

The required power is mainly power for operating the roots blower 13, and is power-saving. That is, since the fixed blade 61a is fixed to the turning part 61 and it is not necessary to rotate the fixed blade 61a by a motor or the like, such electric power is not necessary.

The classification device 1 includes: a housing section 2 that houses the raw powder discharge section 6 and the suction section 4 therein and surrounds the outer periphery; and a delivery pipe (treated raw powder delivery mechanism 7) having a bottom part 22 for taking in the raw powder below the storage part 2 together with the gas, and delivering the raw powder and the gas taken in from the intake port to the raw powder delivery part 6. Therefore, the raw powder containing the fine powder accumulated in the bottom portion 22 of the housing portion 2 without being sucked by the suction portion 4 can be discharged again from the raw powder discharge portion 6. This provides the opportunity to suck the fine powder again from the suction unit 4, and therefore the recovery rate of the fine powder is improved. In particular, by performing the "classifying operation at the time of raw powder supply", the "crushing and classifying operation of raw powder during processing", and the "recovering operation of raw powder (coarse powder) after processing" in separate batch processes, the "crushing and classifying operation of raw powder during processing" can be performed until the recovery rate of fine powder reaches a desired recovery rate, and a stable recovery rate can be achieved.

The classifying device 1 is provided with a discharge port in a discharge transport pipe (the processing raw powder supply pipe 73 of the processing raw powder transport mechanism 7), and the vicinity of the discharge port is defined as a raw powder discharge part 6, and the revolving part 61 is provided in the discharge transport pipe. Therefore, the raw powder accumulated on the bottom 22 of the storage section 2 can be discharged again from the raw powder discharge section 6 having the swirling section 61 in a swirling manner. Thus, since the classification using the centrifugal force effect by the convolution is repeated, the recovery rate of the fine powder can be improved while maintaining the accuracy of the classification of the fine powder and the powder other than the fine powder.

In the classifier 1, the swirling portion 61 is formed by a plurality of fixed blades 61a, and these fixed blades 61a have centers on a straight line passing through the center of the raw powder discharging portion 6 and the center of the suction portion 4, and are radially expanded from the centers and inclined in the circumferential direction. Therefore, the raw powder conveyed to the raw powder discharger 6 collides with the fixed blades 61a of the rotor 61. At this time, clusters contained in the raw powder are pulverized, and at least a plurality of fine monomer powders are separated. The separated fine powder is sucked into the suction unit 4. As a result, the fine powder is newly generated from the cluster to be treated as the coarse powder and collected, and therefore the recovery rate of the fine powder is dramatically improved.

The classifying device 1 is provided with a distance changing means (a position-variable screw 4a provided in the fine powder discharge pipe 5) for changing a distance between the suction part 4 and the raw powder discharge part 6. Therefore, as described above, the accuracy of classifying the fine powder and the powder other than the fine powder is improved, and the accuracy of classification is also improved.

The housing section 2 of the classifying device 1 has a supply nozzle 3, and the supply nozzle 3 is substantially cylindrical with its center line oriented in the vertical direction, is arranged in the tangential direction on the inner wall (swirling flow guide wall 21) of the housing section 2 near the suction section 4, and allows the raw powder to flow in together with the gas. Therefore, the raw powder is also classified when supplied to the classifier 1, and the classification efficiency is good.

Further, since the opening 62 of the raw powder discharging portion 6 and the opening 42 of the inhalation portion 4 are arranged in a similar shape (circular shape in the present embodiment) with the center axes thereof being aligned, the raw powder discharged from the raw powder discharging portion 6 can be stably inhaled into the inhalation portion 4 without variation. Therefore, particles (fine powder) having a desired size can be appropriately taken in.

The present invention is not limited to this embodiment, and may be configured in various other embodiments.

For example, the above description has been made by using "classifying operation at the time of raw powder supply", "crushing and classifying operation of raw powder during treatment", and "recovering operation of raw powder (coarse powder) after treatment" as batch processing, but a continuous processing in which all the operations are performed simultaneously may be configured. Alternatively, the "classifying operation at the time of raw powder supply" and the "crushing and classifying operation of raw powder during processing" may be first executed, and the "recovery operation of raw powder (coarse powder) after processing" may be started after a predetermined time has elapsed, while the movement and stop of each part may be flexibly changed as follows: when a sufficient amount of raw powder is supplied to the housing unit 2, the "classifying operation at the time of raw powder supply" is temporarily stopped, and the "classifying operation at the time of raw powder supply" is restarted when the raw powder of the housing unit 2 is reduced to a predetermined amount.

The raw powder (powder) classified by the classifier 1 is not limited to fly ash, and may be various powders (a plurality of particles having a difference in particle size and/or particle mass) such as wheat flour and cement. In this case, various raw powders may be suitably pulverized and classified.

Industrial applicability

The present invention is applicable to industries related to classification of powder.

Description of the reference symbols

1: a grading device; 2: a storage section; 3: a supply nozzle; 4: a suction portion; 5: a micro powder discharge pipe; 6: a raw powder discharging part; 7: processing the raw powder conveying mechanism; 11: a raw powder bin; 12: a bag filter; 100: and (4) a grading system.

Claims

1. A grading apparatus having:

a raw powder supply pipe for carrying and transporting raw powder in an air flow;

a raw powder discharging unit connected to an upper portion of the raw powder supply pipe for the treatment, and configured to discharge the raw powder together with a gas from an upper surface of the opening;

a suction unit that is disposed opposite to an upper surface of the opening of the raw powder discharge unit at a position spaced apart from the raw powder discharge unit, and sucks the raw powder and a part of the gas from a lower surface of the opening; and

a storage part for storing the raw powder discharge part and the suction part therein, surrounding the outer periphery, and accumulating the raw powder during or after classification,

The raw powder discharge part is configured to have a swirling part inside, the swirling part has a fixed blade inclined in a circumferential direction, the raw powder supplied from the raw powder supply pipe for processing is swirled together with the gas by the swirling part, and the raw powder and the gas are radially discharged from an upper surface of the opening in a swirling state,

the suction portion is configured to suck the raw powder that is discharged radially from an upper surface of the opening of the raw powder discharge portion and travels while swirling, and the classifying device is disposed such that a central axis of the raw powder discharge portion coincides with a central axis of the suction portion.

2. The classifying device according to claim 1, wherein the classifying device is provided with a distance changing means for changing a distance by fixing the suction portion by changing a relative position with respect to the raw powder discharging portion.

3. A grading system having:

a raw powder bin storing raw powder;

the grading device of claim 1 or 2;

a raw powder conveying mechanism that conveys the raw powder from the raw powder bin to the classifying device together with gas via a raw powder supply pipe;

a fine powder discharge pipe connected to the suction part of the classifying device; and

And a bag filter for filtering and collecting the fine powder from the gas containing the fine powder discharged from the classifying device through the fine powder discharge pipe.