JP4783040B2 - Fine powder recovery device for airflow crusher - Google Patents

Description

  The present invention relates to a fine powder recovery device of an airflow type pulverizer used in a fine powder manufacturing process in which various raw materials such as agricultural products and minerals are finely pulverized and airflow classified to recover fine powder.

The airflow type pulverizer includes a first rotating blade and a second rotating blade mounted on the same rotating shaft while being separated from each other by a predetermined distance in a casing (see Patent Document 1), or two rotating blades. There is a type in which a first rotary blade and a second rotary blade that are respectively attached to a shaft and are opposed to each other in a state of being separated from each other by a predetermined distance are provided in a casing (see Patent Document 2).
In such an airflow crusher, as an apparatus for collecting fine powder, as shown in FIG. 7, a suction fan that sucks the finely pulverized fine powder together with air and discharges it from the airflow type pulverizer 51. 52 and a collection hopper 53 (or bag filter) that collects fine powder in the airflow sent from the suction fan 52 and collects it as a product.

A recovery pipe 55 is provided between the discharge port 54 of the airflow crusher 51 and the suction fan 52, and a transport pipe 56 is provided between the suction fan 52 and the recovery hopper 53.
The airflow crusher 51 rotates the first rotary blade 61 and the second rotary blade 62 to generate an airflow swirling in the casing 60.
A swirl region is formed behind the first rotary blade 61, that is, between the first rotary blade 61 and the charging casing 63, and a pulverization region is formed between the first rotary blade 61 and the second rotary blade 62. A classification region is formed between the taper wall 73 of the discharge-side casing 65 and the second rotary blade 62 and along the taper wall 73 in front thereof.

  The raw material thrown into the casing 60 is first swirled in the swirl region and given a flow outward in the radial direction by centrifugal force. to go into. Here, the larger the particle size, the larger the particle diameter, the larger the centrifugal force acts, and the material gathers on the outer peripheral side in the radial direction where the peripheral speed is faster, and is pulverized mainly by grinding of the particles.

  Among the pulverized raw materials, particles having a smaller particle diameter and smaller mass gather on the rotation center side of the second rotary blade 62 having a lower pressure, and are sucked by the suction fan 52 and discharged from the discharge port 54 to the collection tube 55 side together with air. Is done. The particles having a large particle diameter and a large mass do not accompany the sucked air, and return airflow backward generated along the tapered wall 73 of the discharge-side casing 65 in the vicinity of the clearance between the casing 60 and the second rotary blade 62. To return to the grinding area.

The fine powder sucked together with air by the suction fan 52 is transported into the recovery hopper 53 through the transport pipe 56, separated by the recovery hopper 53, and recovered as a product.
In this manner, the fine powder classification by the airflow type pulverizer 51 is performed in the classification region along the tapered wall 73 of the discharge-side casing 65. In the classification region, the return airflow is acting by the second rotary blade 62, but the classification is effectively performed by appropriately operating the collected airflow that sucks the fine powder from the discharge port 54 side. Therefore, the recovered air flow needs a flow rate (flow rate) suitable for classification.

However, it has been difficult to obtain a flow velocity of the recovered air flow suitable for classification in the conventional fine powder recovery device of the air flow pulverizer.
Therefore, it has been considered to provide a gap for introducing outside air between the discharge port and the recovery pipe or in the middle of the recovery pipe (see Japanese Patent Application No. 2003-425793).
All of these gaps are arranged downstream of the discharge port. In particular, the most upstream gap is formed so that the introduction direction of the outside air is directed from the outer periphery of the recovery pipe to the center, and the fine powder is mainly centered. And the airflow on the collecting tube side and the pulverizer side were separated.

However, the gap is arranged on the downstream side of the discharge port and there is a distance from the classification region, and the most upstream side of the gap is such that the introduction direction of the outside air is directed from the outer periphery of the recovery pipe to the center. Thus, an effective recovery airflow is unlikely to act on the classification area.
In addition, since the fine powder is sucked with a suction fan and transported to the recovery hopper, if a recovery air flow is generated with the suction fan, a swirling component is also generated in the air flow. To the swirl airflow of the airflow crusher.

Fine powder adheres to the air contact part inside the suction fan. Therefore, it is necessary to clean the inside of the suction fan after the pulverization operation is completed. In particular, it is difficult to remove the fine powder adhering and remaining on the back surface of the impeller of the suction fan, and the impeller has to be disassembled when performing perfect cleaning.
JP 2000-61340 A JP 2003-1127 A

The present invention solves the above-mentioned problems in the conventional fine powder recovery device of an airflow pulverizer, and provides a fine powder recovery device of an airflow pulverizer capable of generating a recovery airflow with a suitable flow rate. For the purpose.
It is another object of the present invention to provide a fine powder recovery device for an airflow type pulverizer that does not adversely affect the swirling airflow of the airflow type pulverizer, does not require cleaning of a suction fan, and is easy to maintain.

  In the present invention, in order to solve the above-described problem, the first rotary blade and the second rotary blade are provided apart from each other by a predetermined distance in a casing having a tapered wall on the discharge side, and the rear side of the first rotary blade in the casing is provided. A swirling region, a pulverization region between the first rotor blade and the second rotor blade, a classification region between the taper wall and the second rotor blade, and along the taper wall in front of it, are formed at the front end of the taper wall In order to recover the fine powder in the fine powder recovery device of the fine air powder pulverizer used in the fine powder manufacturing process, which finely pulverizes the raw material with an air flow pulverizer with an outlet opening and classifies the air flow to recover the fine powder. A suction fan for generating an airflow and a recovery pipe are provided on the downstream side of the discharge port of the airflow pulverizer, and an opening for introducing outside air is provided in the vicinity of the discharge port.

In the fine powder recovery device of this airflow type pulverizer, an opening for introducing outside air is provided in the vicinity of the discharge port, so that the distance from the classification region is close and a suitable flow rate that effectively acts on the classification region. The recovery airflow can be generated. In addition, it is possible to secure a flow rate necessary for transporting the fine powder from the collection pipe to the collection hopper by introducing the outside air through the transport pipe.
If the opening is formed so that the introduced outside air is directed toward the inner periphery of the downstream collection pipe, the collection air flow is optimized without dividing the collection pipe side and the crusher side air flow, and the fine powder on the inner wall of the collection pipe Can be prevented.

If a conical restrictor for increasing the flow velocity of the recovered airflow is provided in the vicinity of the discharge port, the cross-sectional area of the flow path near the discharge port is reduced, the flow velocity of the recovered airflow is increased, and the suction effect can be enhanced.
When the conical throttle body or a part thereof is attached to the front end portion of the second rotary blade of the airflow crusher, adhesion of fine powder to the conical throttle body can be reduced.
When the spiral blade is formed on the outer periphery of the conical throttle body, an additional recovery airflow is generated, and the recovery efficiency of the fine powder can be improved.
If the amount of outside air introduced by the suction fan is variable, the amount of fine powder recovered can be adjusted by controlling the amount of outside air introduced in accordance with the operating conditions of the airflow type pulverizer that varies depending on the pulverized product.

  The first rotor blade and the second rotor blade are provided in a casing having a tapered wall on the discharge side, and are separated from each other by a predetermined distance. Crushing region between two rotor blades, a classification region is formed between the tapered wall and the second rotor blade, and along the taper wall in front of it, and an airflow type pulverizer with an opening at the front end of the taper wall In the fine powder recovery device of the airflow type pulverizer used in the fine powder manufacturing process, which finely pulverizes the raw material and classifies the airflow and collects the fine powder, a jet nozzle and a recovery pipe that generate a recovery airflow for recovering the fine powder Is provided on the downstream side of the discharge port of the airflow type pulverizer, and an opening for introducing the outside air is provided in the vicinity of the discharge port so that the introduced outside air is directed toward the inner periphery of the collection pipe on the downstream side. Cone to increase the flow speed of It can also be provided a stop member in the vicinity of the discharge port.

In the fine powder recovery device of this airflow type pulverizer, a recovery airflow is generated by jetting gas from a jet nozzle provided on the downstream side of the discharge port toward the discharge side, and the fine powder is sucked and discharged together with air. Discharge from outlet and transport to collection hopper.
For this reason, it is not necessary to place a suction fan in the middle of the transportation route of the fine powder from the discharge port of the airflow crusher to the recovery hopper, and therefore the swirling airflow of the airflow crusher is not adversely affected, and the crushing Cleaning of the fine powder adhering to the suction fan, which has been performed after the work is completed, is also unnecessary.

When the conical throttle body or a part thereof is attached to the front end portion of the second rotary blade of the airflow crusher, adhesion of fine powder to the conical throttle body can be reduced.
When the spiral blade is formed on the outer periphery of the conical throttle body, an additional recovery airflow is generated, and the recovery efficiency of the fine powder can be improved.
If the amount of outside air introduced by the jet nozzle is variable, the flow rate of the recovered airflow can be easily changed by controlling the amount of outside air introduced according to the operating conditions of the airflow type pulverizer that differs depending on the pulverized product. It becomes possible to adjust the amount of recovered powder.

  The fine powder recovery device of the airflow pulverizer of the present invention can generate a recovery airflow with a suitable flow rate. In addition, the swirling airflow of the airflow type pulverizer is not adversely affected, and the maintenance work can be facilitated by eliminating the need for cleaning the suction fan.

FIG. 1 is a configuration diagram of a fine powder recovery device of an airflow type pulverizer according to an embodiment of the present invention.
In this fine powder recovery apparatus, a suction fan 2 and a recovery pipe 5 for generating a recovery air flow for recovering the fine powder are provided on the downstream side of the discharge port 4 of the air flow type pulverizer 1. The recovery pipe 5 has a rear end portion whose diameter is expanded and is fitted to the discharge port 4. An opening 7 for introducing outside air is directed to this portion so that the introduced outside air is directed toward the inner periphery of the collection pipe 5 on the downstream side. It is formed as follows. The suction fan 2 is connected to a transport pipe 6 for transporting the fine powder to the recovery hopper. As the collection hopper, a collection hopper 3 made of a waterproof and moisture-permeable sheet shown in FIG. 3 to be described later can be used.

In the airflow type pulverizer 1, the casing 10 is composed of a charging-side casing 13, a center casing 14, and a discharging-side casing 15. Inside the casing 10, there is a rotating shaft 16 that penetrates the charging-side casing 13. The first rotary blade 11 and the second rotary blade 12 are attached to the front end (left end in the figure) in a state of being separated from each other by a predetermined distance.
The rotating shaft 16 is rotatably supported on the frame 17 via a bearing 18 and is rotated by a motor 19.

The center casing 14 is cylindrical, and a swirl region is formed between the first rotary blade 11 and the charging side casing 13, and a pulverization region is formed between the first rotary blade 11 and the second rotary blade 12.
The charging side casing 13 is provided with a raw material charging port 20 for charging the raw material in a direction perpendicular to the rotating shaft 16, and the raw material supply port 22 opens in a tapered wall 21 whose diameter gradually decreases toward the rear. ing.

The discharge-side casing 15 has a tapered wall 23 whose diameter gradually decreases toward the front, and the discharge port 4 is opened at the front end.
The first rotor blade 11 and the second rotor blade 12 are provided with a plurality of blades 27, 28 radially around the bosses 25, 26, and are rotated by the rotation of the rotating shaft 16 to rotate in the casing 10. Give rise to The blades 27 of the first rotary blade 11 have a shape that generates an air flow that not only swirls but also thrusts forward to facilitate introduction of the raw material from the swirl region to the pulverization region.

The second rotary blade 12 is provided with an inclined surface 29 facing the tapered wall 23 of the discharge-side casing 15 at the tip of the blade 28, and between the discharge-side casing 15 and the second rotary blade 12 and in front thereof. A classification region is formed along the tapered wall 23.
In the pulverization operation, the raw material input from the raw material input port 20 into the airflow type pulverizer 1 enters the casing 10 through the raw material supply port 22, and first swirls by the air flow swirling in the swirl region, and then radial by centrifugal force. An outward flow is given. Further, the discharge port 4 side is depressurized by the air flow generated by the suction fan 2, and a differential pressure is generated between the swirl region and the pulverization region.

Due to this differential pressure and the forward thrust of the airflow generated by the first rotary blade 11, the raw material passes between the blades 27 of the first rotary blade 11 and enters the pulverization region, and is swirled by the airflow. Here, the larger the particle size, the larger the particle diameter, the larger the centrifugal force acts, and the material gathers on the outer peripheral side in the radial direction where the peripheral speed is faster, and is pulverized mainly by grinding of the particles.
Further, among the pulverized raw materials, particles having a smaller particle diameter and smaller mass gather on the rotation center side of the second rotary blade 12 having a lower pressure, and are sucked by the recovered airflow generated by the suction fan 2 and are discharged together with air from the discharge port 4. Discharged. The airflow containing the fine powder is transported from the recovery pipe 5 to the recovery hopper via the transport pipe 6 and recovered as a fine powder product.

Particles having a large particle diameter and a large mass do not accompany the sucked air, and return to the pulverization region by a backward air flow generated along the tapered wall 23.
In this fine powder recovery device, the opening 7 for introducing the outside air is provided in the vicinity of the discharge port 4, so that the distance from the classification region is close and a suitable flow rate that effectively acts on the classification region is recovered. An air flow can be generated. In addition, a flow rate necessary for transporting the fine powder from the recovery pipe 5 to the recovery hopper through the transport pipe 6 by introducing outside air can be secured.

In addition, since the opening 7 is formed so that the introduced outside air is directed toward the inner periphery of the collection pipe 5 on the downstream side, the collected air flow is properly divided without dividing the air flow on the collection pipe 5 side and the airflow type pulverizer 1 side. And the adhesion of the fine powder to the inner wall of the recovery tube 5 can be prevented.
The amount of outside air introduced can be changed by controlling the rotational speed of the suction fan 2. If the amount of outside air introduced by the suction fan 2 is variable, the flow rate of the recovered airflow can be set arbitrarily by changing the amount of outside air introduced according to the operating conditions of the airflow type pulverizer that differs depending on the object to be crushed. Can be adjusted.

FIG. 2 is a configuration diagram of a fine powder recovery device of an airflow crusher provided with a conical throttle body in the vicinity of the discharge port.
In this fine powder recovery apparatus, a conical throttle body 9 is provided in the vicinity of the discharge port 4. The conical throttle body 9 is disposed so that the rear end portion is close to the boss 26 of the second rotary blade 12 and the front end portion extends into the recovery tube 5, and is fixedly supported by the recovery tube 5. Since other configurations are the same as those in FIG. 1, the same members are denoted by the same reference numerals, and description thereof is omitted.

In this fine powder recovery apparatus, since the conical throttle body 9 is provided, the flow passage cross-sectional area near the discharge port 4 is reduced, the flow velocity of the recovered airflow is increased, and the suction effect can be enhanced.
FIG. 3 is a configuration diagram of a fine powder recovery device of an airflow pulverizer according to another embodiment of the present invention, FIG. 4 is an enlarged view of a main part of the fine powder recovery device, and FIG. 5 is a second view of the airflow pulverizer. FIG. 6 is an explanatory view showing a state in which the rear portion of the conical restrictor is provided at the front end of the rotary blade, and FIG. 6 is an explanatory view showing a state in which a spiral blade is formed on the outer periphery of the rear portion of the conical restrictor.

  In this fine powder recovery apparatus, the recovery pipe 5 has a rear portion whose diameter is expanded and is fitted outside so as to cover the discharge-side casing 15 of the airflow type pulverizer 1. The opening 7 is formed so as to direct the introduced outside air toward the inner periphery of the collection pipe 5 on the downstream side. The opening 7 is formed with a jet nozzle 32 that generates a recovery airflow for ejecting air toward the discharge side in the recovery pipe 5 to recover the fine powder.

In order to supply air to the jet nozzle 32, a blower 37 is disposed below the airflow crusher 1, and a blower pipe 38 is provided between the jet nozzle 32 and the blower 37. A conical throttle body 9 is provided in the vicinity of the discharge port 4. A transport pipe 6 for transporting the fine powder to the recovery hopper 3 is connected to the recovery pipe 5.
In this fine powder recovery apparatus, fine powder pulverized by the airflow type pulverizer 1 together with air is ejected from the jet nozzle 32 provided along the outer periphery of the discharge port 4 toward the discharge side. An air flow is generated between the collection pipe 5 and the conical throttle body 9 to be sucked and discharged from the discharge port 4 and transported to the collection hopper 3 through the transport pipe 6. The flow rate of the jet nozzle 32 can be changed by controlling the rotational speed of the blower 37.

If the amount of outside air introduced by the jet nozzle 32 is variable, the flow rate of the recovered airflow can be easily changed by controlling the amount of outside air introduced according to the operating conditions of the airflow type pulverizer 1 depending on the object to be crushed. The amount of fine powder recovered can be adjusted.
The recovery hopper 3 has a cylindrical outer portion and a waterproof and moisture permeable sheet having a conical lower portion. The outer periphery of the collection hopper 3 is supported by a hopper frame 31.

A fine powder recovery port 34 is formed at the bottom of the recovery hopper 3 and a recovery valve 35 is provided for taking out and recovering the fine powder.
The waterproof and moisture permeable sheet used for the recovery hopper 3 has an average pore diameter of 0.01 to 10 μm, preferably 0.1 to 1 μm. When the average pore diameter is smaller than 0.01 μm, there are difficulties in production, and when it is larger than 10 μm, the air permeability becomes too large and the fine powder may permeate. When the porosity is less than 50%, it is difficult to ensure the necessary moisture permeability. Conversely, when the porosity exceeds 98%, the strength of the film is lowered, so the porosity is 50 to 98%, preferably 60 to It should be 95%.

The configuration of the airflow fine pulverizer 1 is the same as that shown in FIG.
The jet nozzle 32 controls the rotational speed of the blower 37 and changes the flow rate according to the operating conditions of the airflow type pulverizer 1 depending on the pulverization target, thereby obtaining a flow velocity of the recovered airflow suitable for collecting fine powder. , The fine powder can be discharged appropriately.
The airflow containing fine powder flows from the collection pipe 5 to the collection hopper 3 through the transport pipe 6.
Since the recovery hopper 3 is composed of a waterproof and moisture-permeable sheet, when an air flow containing fine powder flows in, the air passes through the waterproof and moisture-permeable sheet and flows out of the recovery hopper 3 into the atmosphere. Slowly descend to the bottom of 3.

The fine powder adhering to the waterproof and moisture-permeable sheet is collected by dropping or dropping to the bottom of the waterproof and moisture-permeable sheet by applying deformation or vibration. The collected fine powder is taken out by opening the collection valve 35 and collected as a fine powder product.
The blower 37 is disposed on the upstream side of the discharge port 4, and it is not necessary to dispose a suction fan in the course of the fine powder transport path from the discharge port 4 of the airflow crusher 1 to the recovery hopper 3. Therefore, it does not adversely affect the swirling airflow of the airflow-type pulverizer 1, and the cleaning operation of the fine powder adhering to the suction fan that has been performed after the pulverization operation is completed is unnecessary.

As shown in FIG. 5, the conical throttle body 9 is divided into front and rear parts, and the conical throttle body front part 9A is fixedly supported to the recovery pipe 5, and the conical throttle body rear part 9B is fixed to the conical throttle body front part 9A. When attached to the front end of the second rotary blade 12 of the airflow crusher 1 in a state of being close to the rear end, the conical throttle body rear portion 9B rotates integrally with the boss 26 of the second rotary blade 12, and the cone It is possible to reduce the adhesion growth of fine powder on the shaped diaphragm 9.
As shown in FIG. 6, when the spiral blade 9S is formed on the outer periphery of the conical throttle body rear portion 9B provided at the front end of the second rotary blade 12 of the airflow crusher 1, an additional recovered airflow is generated due to the swirling effect. The recovery efficiency of the generated fine powder can be improved.

It is a block diagram of the fine powder collection | recovery apparatus of the airflow type grinder which is one Embodiment of this invention. It is a block diagram of the fine powder collection | recovery apparatus of the airflow type | formula grinder which provided the cone-shaped throttle body near the discharge port. It is a block diagram of the fine powder collection | recovery apparatus of the airflow-type grinder which is other embodiment of this invention. It is an enlarged view of the principal part of a fine powder collection | recovery apparatus. It is explanatory drawing of the state which attached the conical throttle body rear part to the front end of the 2nd rotary blade of an airflow-type grinder. It is explanatory drawing of the state which formed the spiral wing | blade on the outer periphery of a truncated cone-shaped aperture. It is a block diagram of the fine powder collection | recovery apparatus of the conventional airflow type grinder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airflow type crusher 2 Suction fan 3 Recovery hopper 4 Discharge port 5 Recovery pipe 6 Transport pipe 7 Opening part 9 Conical throttle body 9A Conical throttle body front part 9B Conical throttle body rear part 9S Spiral blade 10 Casing 11 First rotation Blade 12 Second rotor blade 16 Rotating shaft 32 Jet nozzle 37 Blower 38 Blower tube

Claims (9)

A first rotor blade and a second rotor blade are provided apart from each other by a predetermined distance in a casing having a tapered wall on the discharge side, a swirl region behind the first rotor blade in the casing, and the first rotor blade and the second rotor. Crushing region between blades, classification region is formed between the tapered wall and the second rotor blade and along the tapered wall in front of it, and the raw material is produced by an airflow type pulverizer with a discharge port opened at the front end of the tapered wall. A fine powder recovery device of an air flow type pulverizer used in a fine powder manufacturing process for finely pulverizing and classifying an air flow to recover a fine powder,
A suction fan that generates a recovery airflow for collecting fine powder and a recovery pipe are provided downstream of the outlet of the airflow crusher, an opening for introducing outside air is provided near the outlet, and the flow velocity of the recovered airflow A fine powder recovery device for an airflow crusher, characterized in that a conical constriction body is provided in the vicinity of the discharge port for speeding up the process.   2. The fine powder recovery device for an airflow pulverizer according to claim 1, wherein the opening is formed so that the introduced outside air is directed toward the inner periphery of the downstream recovery pipe. 3. A fine powder recovery apparatus for an airflow pulverizer according to claim 1 or 2, wherein the conical throttle body or a part thereof is attached to a front end portion of the second rotary blade of the airflow pulverizer. The fine powder recovery apparatus for an airflow type pulverizer according to any one of claims 1 to 3, wherein spiral blades are formed on the outer periphery of the conical throttle body . The fine powder recovery device for an airflow type pulverizer according to any one of claims 1 to 4, wherein the amount of outside air introduced by the suction fan is variable . A first rotor blade and a second rotor blade are provided apart from each other by a predetermined distance in a casing having a tapered wall on the discharge side, a swirl region behind the first rotor blade in the casing, and the first rotor blade and the second rotor. Crushing region between blades, classification region is formed between the tapered wall and the second rotor blade and along the tapered wall in front of it, and the raw material is produced by an airflow type pulverizer with a discharge port opened at the front end of the tapered wall. A fine powder recovery device of an air flow type pulverizer used in a fine powder manufacturing process for finely pulverizing and classifying an air flow to recover a fine powder,
A jet nozzle that generates a recovery air flow for collecting fine powder and a recovery pipe are provided on the downstream side of the outlet of the airflow crusher, and an opening for introducing outside air is provided in the vicinity of the outlet to introduce the outside air downstream. A fine powder recovery apparatus for an airflow type pulverizer , characterized in that a conical constriction body is provided in the vicinity of the discharge port so as to be directed toward the inner periphery of the side recovery pipe . 7. A fine powder recovery apparatus for an airflow pulverizer according to claim 6, wherein the conical throttle body or a part thereof is attached to a front end portion of the second rotary blade of the airflow pulverizer. 8. The fine powder recovery device for an airflow crusher according to claim 6 or 7, wherein spiral blades are formed on the outer periphery of the conical throttle body . The apparatus for collecting fine powder of an airflow pulverizer according to any one of claims 6 to 8, wherein the amount of outside air introduced by the jet nozzle is variable .

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