JP4503338B2 - Raw material charging method and raw material charging apparatus for airflow type fine grinding machine - Google Patents

Description

  The present invention relates to a raw material charging method and a raw material charging apparatus for an airflow type fine grinding machine used for grinding various raw materials such as agricultural products and minerals.

  Conventionally, an airflow type fine grinder has been used to grind various raw materials such as agricultural products and minerals. As shown in FIG. 5 and FIG. 6, in this airflow type fine pulverizer, the casing 10 is composed of an input side casing 13, a center casing 14, and an exhaust side casing 15. The first rotary blade 11 and the second rotary blade 12 are attached to a front end (left end in FIG. 5) of the shaft 16 that penetrates the side casing 13 in a state of being separated from each other by a predetermined distance. The shaft 16 is rotatably supported by a frame 17 via a bearing (not shown), and is rotated by a motor 20.

The center casing 14 has a cylindrical shape, and a pulverization region C is formed between the first rotary blade 11 and the second rotary blade 12.
The charging-side casing 13 is provided with a curved wall 19 whose diameter gradually decreases from the rear end of the center casing 14 toward the rear, and a gap between the first rotary blade 11 of the center casing 14 and the charging-side casing 13 is provided. Thus, a swivel region B is formed.
Further, the charging casing 13 is provided with a raw material charging portion 18 for charging the raw material in a direction perpendicular to the shaft 16, a raw material supply port 21 is opened in the curved wall 19, and the rear portion of the swivel region B The curved wall 19 is an introduction part A for smoothly introducing the raw material from the raw material supply port 21 to the first rotary blade 11 side.
The discharge side casing 15 has a tapered wall 22 whose diameter gradually decreases toward the front, and a discharge port 23 is opened at the front end. A suction fan is connected to the discharge port 23 via a suction pipe.

  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. The first rotor blade 11 and the second rotor blade 12 are rotated by the rotation of the shaft 16 and rotate in the casing 10. Cause it to occur. 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 the introduction of the raw material from the swirl region B to the pulverization region C.

The second rotary blade 12 is provided with an inclined surface 29 facing the tapered wall 22 of the discharge-side casing 15 at the tip of the blade 28, and the classification gap between the second rotary blade 12 and the discharge-side casing 15. A classification region D is formed along the tapered wall 22 in front of the classification wall D.
The airflow fine pulverizer serves as the raw material charging device 3, the raw material hopper 30, the charging hopper 31 provided at the upper end of the raw material charging unit 18, and the raw material is extracted from the raw material hopper 30 and supplied to the charging hopper 31 constantly. And an electromagnetic feeder 32.

  The raw material extracted from the raw material hopper 30 by the electromagnetic feeder 32 and supplied to the raw material input part 18 enters the introduction part A of the input side casing 13 through the raw material supply port 21. This raw material is swirled by the airflow swirling in the introduction part A, and a flow toward the radially outer side is given by the centrifugal force, so that the density of the raw material is low in the central part and high in the outer peripheral part. Further, the suction fan sucks the discharge port 23 side, and a differential pressure is generated between the swivel region B and the pulverization region C.

Due to the differential pressure and the forward thrust of the air flow generated by the first rotary blade 11, the raw material in the swirl region B gradually moves from the introduction portion A toward the first rotary blade 11 along the curved wall 19. The peripheral speed of the revolving raw material gradually increases from the raw material supply port 21 toward the first rotary blade 11, and the peripheral speed is substantially equal to the peripheral speed of the pulverization region C in the vicinity of the first rotary blade 11.
The swirling raw material stays in the swirling region B to some extent, and then passes between the blades 27 of the first rotary blade 11 by the differential pressure to enter the pulverizing region C and swirls 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 near the rotation center of the second rotary blade 12 having a lower pressure, and are sucked by a suction fan and discharged together with air from the discharge port 23, and are collected later. It is collected as a pulverized product by the collecting means. Particles having a large particle size and a large mass do not accompany the sucked air and return to the pulverization region C by a backward return airflow generated in the outer peripheral portion of the classification region D along the tapered wall 22 (see, for example, Patent Document 1). ).

In the airflow type fine pulverizer, in a steady pulverization state where a predetermined amount of raw material exists in the pulverization region C, the pulverization is performed without any trouble by the raw material charging method in which a constant constant amount of raw material is constantly charged as described above.
However, at the start of operation, raw material enters the introduction part A, but sufficient raw material does not yet enter the pulverization region C. For this reason, in the initial stage of operation, there is no obstruction in the pulverization region C from the backward return airflow generated from the classification region D to the outer peripheral portion of the second rotary blade 12, and as shown in FIG. It flows backward to the introduction part A of the swirl region B and further to the raw material charging part 18. When the amount of the raw material in the introduction part A is small and the momentum of the return air flow R wins, the raw material is not supplied to the pulverization region C any time. The raw material could not be smoothly supplied by blowing back, and the raw material could be blown out from the charging hopper 31 as shown in FIG.
JP 2000-61340 A

  The present invention solves the above-mentioned problem in the raw material charging of the airflow fine pulverizer, and the raw material charging method of the airflow fine pulverizer and the airflow fine pulverization capable of smoothly supplying the raw material even in the initial operation state. It aims at providing the raw material input device of a machine.

  In the raw material charging method of the airflow type fine pulverizer according to the present invention, the first rotary blade and the second rotary blade are provided in the casing so as to be separated from each other by a predetermined distance, and the swirl region is provided behind the first rotary blade in the casing. A crushing region is formed between the rotor blade and the second rotor blade, a taper wall having a diameter gradually decreasing from the crushing region to the front is provided in the casing, and an inclined surface facing the taper wall is provided in the second rotor blade. Airflow type fine pulverization that forms a classification gap between the taper wall and the inclined surface, and finely pulverizes the raw material charged into the swirl region from the raw material charging portion with the swirling airflow generated by the rotation of the first and second rotor blades. In the machine, the above problem is solved by switching so that a larger amount of raw material is charged at a time in the initial operation state and then the steady amount of raw material is charged after shifting to the steady pulverization state.

In the raw material charging method of the airflow type fine pulverizer of the present invention, in the initial operation state, a larger amount of raw material than the steady charging amount is charged at a time, so the return airflow is overcome from the start of operation until the transition to the steady pulverization state. The raw material can be introduced into the introduction section and supplied to the pulverization region. There is no risk that the raw material will be blown out of the charging hopper.
When the raw material is sufficiently supplied to the pulverization region, a steady pulverization state is formed in the pulverization region, and the raw material blocks the return airflow from flowing back to the swirl region. Switch so that a constant amount of raw material is charged.

  The raw material charging device of the airflow type fine pulverizer according to the present invention is provided with a first rotary blade and a second rotary blade separated from each other by a predetermined distance in a casing, a swirl region behind the first rotary blade in the casing, and a first A crushing region is formed between the rotor blade and the second rotor blade, a taper wall having a diameter gradually decreasing from the crushing region to the front is provided in the casing, and an inclined surface facing the taper wall is provided in the second rotor blade. Airflow type fine pulverization that forms a classification gap between the taper wall and the inclined surface, and finely pulverizes the raw material charged into the swirl region from the raw material charging portion with the swirling airflow generated by the rotation of the first and second rotor blades. The machine is equipped with raw material supply means capable of variably controlling the input amount so that a larger amount of raw material than the normal input amount is input at a time in the initial operation state and the steady input amount of raw material is input after shifting to the steady pulverization state. Yes.

In the raw material input device of the airflow type fine pulverizer of the present invention, the raw material supply means inputs a larger amount of raw material at a time than the normal input amount in the initial operation state, and after the transition to the steady pulverization state, the normal input amount of the raw material is input. As described above, since the input amount of the raw material can be variably controlled, it is possible to overcome the return airflow and input the raw material to the introduction portion from the start of operation until the steady pulverization state is reached.
Further, when the raw material charging device of the airflow type fine pulverizer is provided with the backflow prevention means, the backflow prevention means reduces the momentum of the return airflow, so that the raw material is more smoothly introduced into the introduction portion, and further, the raw material is ejected from the charging hopper. Is also prevented.

  According to the raw material charging method of the airflow fine pulverizer and the raw material charging apparatus of the airflow fine pulverizer according to the present invention, the raw material can be supplied smoothly even in the initial operation state.

FIG. 1 is a block diagram of an airflow fine pulverizer showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the internal structure of the casing of the airflow fine pulverizer, and FIG. 3 is a cross-sectional view taken along the line EE of FIG. 4 and 4 are configuration diagrams of an airflow type fine pulverizer showing an example in which a rotary feeder is provided as a raw material supply means.
In the airflow type fine pulverizer, the casing 10 is composed of an input side casing 13, a center casing 14, and a discharge side casing 15. Inside the casing 10, a front end of a shaft 16 that penetrates the input side casing 13 ( The first rotary blade 11 and the second rotary blade 12 are attached to the left end in FIG. 2 in a state where they are separated from each other by a predetermined distance. The shaft 16 is rotatably supported by a frame 17 via a bearing (not shown), and is rotated by a motor 20.

The center casing 14 has a cylindrical shape, and a pulverization region C is formed between the first rotary blade 11 and the second rotary blade 12.
The charging-side casing 13 is provided with a curved wall 19 whose diameter gradually decreases from the rear end of the center casing 14 toward the rear, and a gap between the first rotary blade 11 of the center casing 14 and the charging-side casing 13 is provided. Thus, a swivel region B is formed.
Further, the charging casing 13 is provided with a raw material charging portion 18 for charging the raw material in a direction perpendicular to the shaft 16, a raw material supply port 21 is opened in the curved wall 19, and the rear portion of the swivel region B The curved wall 19 is an introduction part A for smoothly introducing the raw material from the raw material supply port 21 to the first rotary blade 11 side.
The discharge side casing 15 has a tapered wall 22 whose diameter gradually decreases toward the front, and a discharge port 23 is opened at the front end. A suction fan is connected to the discharge port 23 via a suction pipe.

  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. The first rotor blade 11 and the second rotor blade 12 are rotated by the rotation of the shaft 16 and rotate in the casing 10. Cause it to occur. 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 the introduction of the raw material from the swirl region B to the pulverization region C.

The second rotary blade 12 is provided with an inclined surface 29 facing the tapered wall 22 of the discharge-side casing 15 at the tip of the blade 28, and the classification gap between the second rotary blade 12 and the discharge-side casing 15. A classification region D is formed along the tapered wall 22 in front of the classification wall D.
This airflow type fine pulverizer serves as a raw material charging device 3, a raw material hopper 30, a charging hopper 31 provided at the upper end of the raw material charging unit 18, and a variable capacity for extracting the raw material from the raw material hopper 30 and supplying it to the charging hopper 31. And a screw feeder 33 of the type.

The screw feeder 33 includes an input amount control unit 36. In an initial operation state, a large amount of raw materials are input at a time, supply of the raw materials is temporarily stopped, and after shifting to a steady pulverization state, a constant input amount of raw materials is input. Thus, the rotation speed can be controlled by a timer.
Instead of the screw feeder 33, other variable capacity type material supply means such as the rotary feeder 37 shown in FIG. 4 may be provided.

In the charging hopper 31, backflow prevention plates 34 for preventing the return airflow from the raw material charging unit 18 from being blown out are arranged in multiple stages. The backflow prevention plate 34 is resistant to the return airflow, but has a cross-sectional Λ shape that does not interfere with the introduction of the outside air into the pulverizer, and prevents a good swirling airflow during steady operation. Don't be.
A raw material dropping passage 35 is formed immediately above the raw material charging portion 18 so that the raw material charged is not scattered by the backflow prevention plate 34.

  At the start of operation, the raw material is extracted from the raw material hopper 30 by the screw feeder 33, and is input to the raw material input unit 18 through the input hopper 31. The raw material passes through the raw material supply port 21 and enters the introduction part A of the swivel region B of the charging side casing 13, but at this time, the pulverization region C does not contain enough raw material yet. Therefore, the input amount control unit 36 increases the supply amount of the raw material of the screw feeder 33 and performs control so that a larger amount (three to ten times) of the raw material is input at a time than the steady input amount.

In this way, in the initial operation state, a larger amount of raw material than the steady charge amount is charged at a time, so that the raw material is thrown into the introduction part A overcoming the return airflow from the start of operation until the transition to the steady pulverization state. The The charging hopper 31 is provided with a backflow prevention plate 34 to reduce the momentum of the return airflow, so that the raw material is more smoothly charged into the introduction part A. Further, the raw material is prevented from being ejected from the charging hopper 31.
The raw material that has entered the introduction section A is swirled by the airflow swirling in the introduction section A, and is given a flow toward the outside in the radial direction by centrifugal force, so that the density of the raw material is low in the central portion and high in the outer peripheral portion. Further, the suction fan sucks the discharge port 23 side, and a differential pressure is generated between the swivel region B and the pulverization region C.

Due to the differential pressure and the forward thrust of the air flow generated by the first rotary blade 11, the raw material in the swirl region B gradually moves from the introduction portion A toward the first rotary blade 11 along the curved wall 19. The peripheral speed of the revolving raw material gradually increases from the raw material supply port 21 toward the first rotary blade 11, and the peripheral speed is substantially equal to the peripheral speed of the pulverization region C in the vicinity of the first rotary blade 11.
The swirling raw material stays in the swirling region B to some extent, and then passes between the blades 27 of the first rotary blade 11 by the differential pressure to enter the pulverizing region C and swirls 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 near the rotation center of the second rotary blade 12 having a lower pressure, and are sucked by a suction fan and discharged together with air from the discharge port 23, and are collected later. It is collected as a pulverized product by the collecting means. Particles having a large particle diameter and a large mass do not accompany the sucked air, and return to the pulverization region C by a backward return airflow generated in the outer peripheral portion of the classification region D along the tapered wall 22.
When the raw material in the pulverization region C increases and shifts to the steady pulverization state, the input amount control unit 36 decreases the supply amount of the raw material of the screw feeder 33 and switches so that the raw material of the constant input amount is input. Thereafter, the steady pulverization state is maintained by continuing to supply the raw material in a constant amount.

It is a block diagram of the airflow type fine pulverizer which shows one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure inside the casing of an airflow type fine pulverizer. It is the EE sectional view taken on the line of FIG. It is a block diagram of the airflow type fine crusher which shows the example which provided the rotary feeder as a raw material supply means. It is a block diagram of the conventional airflow type fine crusher. It is a longitudinal cross-sectional view which shows the internal structure of the casing of the conventional airflow type fine crusher. It is explanatory drawing of the return airflow at the time of the operation start of the conventional airflow type fine crusher.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Raw material injection apparatus 10 Casing 11 1st rotary blade 12 2nd rotary blade 13 Input side casing 14 Center casing 15 Discharge side casing 16 Shaft 17 Frame 18 Raw material input part 19 Curved wall 20 Motor 21 Raw material supply port 22 Tapered wall 23 Discharge port 25, 26 Boss 27, 28 Blade 29 Inclined surface 30 Raw material hopper 31 Input hopper 33 Screw feeder 34 Backflow prevention plate 35 Falling passage 36 Input amount control unit 37 Rotary feeder

Claims (3)

  The first rotor blade and the second rotor blade are provided in the casing so as to be separated from each other by a predetermined distance, the swirl region is located behind the first rotor blade in the casing, and the pulverization region is between the first rotor blade and the second rotor blade. A tapered wall whose diameter gradually decreases from the pulverization region to the front of the casing, and an inclined surface facing the tapered wall is provided on the second rotor blade to form a classification gap between the tapered wall and the inclined surface. In the airflow-type fine pulverizer that finely pulverizes the raw material charged into the swirl zone from the raw material charging unit with the swirling airflow generated by the rotation of the first rotor blade and the second rotor blade, in the initial stage of operation, a larger amount than the steady charging amount The raw material charging method of the airflow type fine pulverizer is characterized in that it is switched so that a constant amount of the raw material is charged after the raw material is charged at once and after shifting to the steady pulverization state.   The first rotor blade and the second rotor blade are provided in the casing so as to be separated from each other by a predetermined distance, the swirl region is located behind the first rotor blade in the casing, and the pulverization region is between the first rotor blade and the second rotor blade. A tapered wall whose diameter gradually decreases from the pulverization region to the front of the casing, and an inclined surface facing the tapered wall is provided on the second rotor blade to form a classification gap between the tapered wall and the inclined surface. In the airflow-type fine pulverizer that finely pulverizes the raw material charged into the swirl zone from the raw material charging unit with the swirling airflow generated by the rotation of the first rotor blade and the second rotor blade, in the initial stage of operation, a larger amount than the steady charging amount The raw material input device of the airflow type fine pulverizer is equipped with a raw material supply means capable of variably controlling the input amount so that a constant amount of the raw material is input after the raw material is input at a time and after shifting to the steady pulverization state .   3. The raw material charging device for an airflow type fine pulverizer according to claim 2, further comprising a backflow preventing means.

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