JPH0787904B2 - Airflow type fine crusher - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an air flow for pulverizing solid substances such as pharmaceuticals, agricultural chemicals, foods, chemical products, synthetic resins, metallic materials, and inorganic substances into fine powders having a narrow particle size distribution range of about several tens of μm to about 1 μm. For more details about the type of fine pulverizer,
The present invention relates to an air flow type fine pulverizer suitable for pulverizing low melting point, weak heat, adhesiveness, or abradable substances.

[0002]

2. Description of the Related Art As a conventional device of this kind, for example, (1) Japanese Patent Publication No. 54-13631, (2) Japanese Patent Publication No. 6
No. 2-8215, and (3) Japanese Patent Publication No. 60-184.
The one disclosed in Japanese Patent No. 54 is known. In the devices disclosed in these publications, the supplied solid matter (hereinafter referred to as pulverized material) is pulverized by a gas jet, and the powder produced by the pulverization is sorted by a classifying means in the upper part of the pulverizing chamber. The fine powder having a particle size of a predetermined size or less is taken out of the apparatus by a transport dust collecting means (not shown), and the remaining coarse powder is returned to the crushing chamber again and repeatedly crushed.

Of these, in the publications (1) and (2), the crushed material is sent to the crushing chamber by some mechanical transportation means, and is passed through a nozzle into the powder layer stored in the crushing chamber. A gas jet is blown into the powder, and the powder is crushed by collision and friction between the powders. The crushed crushed product is carried to the classification zone by the crushing action and the depressurized air flow, and the coarse powder selected by the forced rotation type classification rotor is
As shown in Fig. 4; 8; 14 of the publication (1), returned to the means for transporting the crushed material, or Fig. Of the publication (1).
15 and gazette (2), they are directly returned to the powder layer by gravity.

Further, in the above-mentioned publication (3), below the crushed material hopper, the crushed material is sucked by a gas jet flowing from an injector nozzle and then accelerated in an accelerating pipe toward a crushing chamber. On the other hand, the coarse powder selected by the classifying means is sucked by a gas jet flowing from another facing nozzle, is accelerated in another accelerating pipe, and is crushed and conveyed from the opposite side. Collide in the grinding chamber. The crushed material generated by the collision in the accelerating pipe and in the crushing chamber is carried to the classification chamber by the air flow that has a surplus power, and only the fine powder is sent out by the cyclone principle, and the coarse powder is circulated by the air flow and repeatedly crushed Be affected.

[0005]

(A) First, there are the following problems regarding the supply of crushed material. In the classifying means of the above publications (1) and (2), the static pressure of the crushing chamber becomes equal to or higher than the atmospheric pressure of the outside world due to the fan action of the classifying rotor, which is the classifying means. In order to carry it in to Fig. 5 of Publication (1);
Or imparting gas shut-off device, such as a double damper or a rotary valve as shown in fig 7, or although the publication (2) description is omitted, following the dust collector after the device suction It is necessary to connect a blower to keep the crushing chamber always below the atmospheric pressure. If this is not done, there is a drawback that the crushed material is blown out together with the gas from the crushed material hopper.

Further, in the publication (3), the negative pressure generated by the jet of gas ejected from the injector nozzle sucks the crushed material from the crushed material hopper, so that a problem may occur even if the pressure inside the crushing chamber is higher than the atmospheric pressure of the outside. There is no. However, in the accelerating pipe that follows the injector nozzle, the gas jet entrained with the debris passes at a high speed around the sonic velocity,
There is a drawback that the abrasion powder of the vessel wall is mixed in the crushed material, resulting in contamination of the crushed product and wear of the members.

(B) Next, regarding classification, there are the following problems. In the above publications (1) and (2), assuming that a nozzle having a fixed opening is used and the working capacity (pressure and generated air volume) of the compressed gas source is always utilized to the maximum, the air volume passing through the classification rotor is large. The force of the air flow passing through the rotor to draw the particles into the rotor depends only on the size of the particles. Therefore, by artificially changing the rotation speed of the classification rotor to adjust the swirling air velocity around the rotor and changing the centrifugal acceleration that acts on the particles swirling with the air flow, even particles of the same size The acting centrifugal force can be changed. Therefore, the classification point (maximum particle size in the crushed product) can be arbitrarily changed independently of the crushing action. However, if the powder layer in the crushing chamber is thin and the depletion of the gas jet is insufficient, as at the end of the work, large particles that exceed the classification point will rise in the rising air and enter the classification rotor. There is a problem that large particles called “Kobi” are mixed into the crushed product.

Further, in the publication (3), if it is premised that the working capacity of the compressed gas source is always maximized by using a nozzle having a fixed opening, the swirling speed of the air flow in the classification chamber remains almost unchanged. Since the centrifugal acceleration acting on the particles is almost constant, the average particle size of the crushed product can be changed to some extent by changing the solid-gas ratio (ratio of the amount of crushed material supplied and the amount of air flow).
Due to the cyclone principle, changing the classification point becomes difficult.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is (A) that the static pressure in the crushing chamber slightly exceeds the atmospheric pressure of the outside world. Even though there is no special additive such as a gas shutoff device, the crushed material does not blow out from the crushed material supply device during the work, and (B) the classification point can be adjusted. Therefore, it is an object of the present invention to provide an airflow type fine pulverizer capable of obtaining a crushed product which does not cause a problem called "tobi".

[0010]

In order to achieve the above object, in the present invention, a crushed material supplied to a crushing chamber through an injector nozzle is crushed by an injector nozzle and a counter nozzle, An airflow in which fine powder of a certain size or less in the pulverized material is classified by the classifying means in the classification chamber above the crushing chamber and taken out of the device, and coarse powder of a certain size or more is returned to the crushing chamber by the circulation means and crushing is repeated In a fine pulverizer, the counter nozzle is attached to the crushing chamber so as to face the center line of the injector nozzle at an obtuse angle so as to face the center line of the injector nozzle. The first core is arranged, and the needle is arranged as the second core on the center line of the counter nozzle.
Of the core body and the second core body are provided with tubular tubular sheets surrounding the peripheries, and an annular portion formed in a gap between the core body and the tubular sheet surrounding the core body serves as a gas passage. A gas flow type fine pulverizer in which a passage is provided with a throat portion whose cross-sectional area is first reduced and then expanded along with the flow of gas, and compressed gas is introduced from the outside of the pulverization chamber of this gas passage toward the inside of the pulverization chamber. is there.

In the above structure, the classifying means is a rotary impeller having the closed end face side fixed to the drive shaft and having a large number of strip-shaped blades parallel to the axis on the outer peripheral surface. It has a different-diameter cylindrical outer shape having a small-diameter cylindrical portion and a small-diameter cylindrical portion, and an opening is formed at the end of the small-diameter cylindrical portion by a square ring, and an annular partition plate is provided near the outer periphery of this square ring. A classification case cover with a fine powder outlet is attached to the opening side of the classification case that houses the rotary impeller, and the classification chamber is formed by a double cylindrical housing that surrounds the rotary impeller. On the front side of the closed end face attached to the drive shaft, an air flow preliminary swirl chamber is provided by a cylindrical housing forming an extension surface of the inner cylinder of the double cylinder, and the powder circulating means is a counter nozzle. Is in Is formed so as to form an obtuse angle with respect to the center line of the injector / nozzle, and from the upper side of this intersection point toward the air flow preliminary swirl chamber formed in the classifying means, is deflected and connected to the axis of the rotary impeller. Crushed material transportation passage,
Provided is an airflow type fine pulverizer formed by an annular space portion formed between double cylinders of a classification chamber and a coarse powder return passage connected so as to be close to one tip of a nozzle attached to the pulverization chamber.

Further, in the above construction, the injector nozzle and the counter nozzle have a conical surface which is gradually reduced toward the crushing chamber at the tip of the hollow spindle or needle forming the core thereof. On the inner surface of each tubular sheet facing the conical surface of these cores,
A first conical surface having a cone angle larger than the cone angle of the core body that contracts from the compressed gas introduction side toward the crushing chamber side, and a second cone surface or a cylindrical surface having a cone angle smaller than the cone angle of the core body. : it is formed continuously, the middle portion of the gap between the outer surface of the inner surface and the core of the tubular sheet, airflow pulverizer made is formed throat an annular cross section槓is minimized, or
In addition to having these configurations, the hollow spindle
A crushed material supply device that includes a screw shaft in the opening on the anti-crushing side.
( EN) Provided is an air flow type fine pulverizer in which a device is loosely inserted .

Further, in the above configuration, the hollow spindle or needle conical surface formed on the tip thereof
For each tubular sheet with the tip of the
Air-flow type fine pulverization that is installed so that it can be moved back and forth by means of
Machine or hollow spin with these configurations
Grinding material containing a screw shaft in the opening on the anti-crushing side of the dollar
Provided is an air flow type fine pulverizer in which a supply device is loosely inserted .

Furthermore, in the above construction, the classifying case is provided with a partition plate on the inner surface of the classifying case cover attached to the opening thereof, and the inner peripheral surface of the partition plate serves as a classifying means for the rotary impeller. An annular gas reservoir, which is held close to the outer peripheral surface of the rectangular ring forming the end of the small-diameter cylindrical portion, and is connected to the compressed gas source between the inner peripheral surface of the partition plate and the outer peripheral surface of the rectangular ring, Provided is an air flow type fine pulverizer provided with a primary side gap and a secondary side gap that respectively communicate this gas reservoir with a classification chamber and a fine powder outlet.

[0015]

[Operation] When compressed gas is supplied to the air flow type crusher and the crushed material is put into the crushed material hopper to operate the apparatus, the crushed material carried by the screw shaft is transferred to the tip of the injector / nozzle.
Wrapped in a gas jet and out injection from the conical surface annular space portion formed in the outer parts facing into the grinding chamber, it is sucked together with the secondary gas coming out of a hole provided screw case, acceleration To be done. As a result, the pulverized materials collide with each other and are pulverized by frictional action, and the finely divided powder is accompanied by the air flow depressurized by the pulverization, passes through the pulverized material transportation passage, and is applied to the axis of the rotary impeller. The airflow preliminary swirl chamber is deflected in the opposite direction, swirls in the same direction as the rotation of the rotary impeller, and enters the classification chamber while moving the coarse particles to the peripheral wall due to the difference in centrifugal force.

Here, the powder particles also swirl around the impeller in accordance with the swirling airflow generated by the rotary impeller and receive a centrifugal force corresponding to the size of the particles. On the other hand, the air flow blown out from the nozzle forms an inward flow evenly over the outer peripheral surface of the rotary impeller with the help of the suction blower following the device, which allows the powder particles to be conveyed inward depending on the size. Receive power. Therefore, only the fine powder having a particle size of a predetermined size or less overcomes the centrifugal force, is taken into the impeller by the conveying force of the airflow, and is conveyed to the dust collector through the fine powder outlet of the classification case cover. The coarse powder is not leaked from the gap between the inner peripheral surface of the partition plate and the impeller to the fine powder outlet in a short-circuited manner, and becomes a U-turned air flow while swirling through the gap between the inner cylinder surrounding the rotary impeller and the partition plate. Ride and go through the coarse powder return passage to the grinding chamber. Formed outside the conical surface at the tip of the counter nozzle
The gas jet blown out from the formed annular space portion sucks and accelerates the coarse powder, and collides with the pulverized material accelerated by the jet blown out from the injector nozzle on the opposite side.

In the crushing chamber, the cavity where the gas jet passes and the concentration of the powder is relatively low, and the periphery of the cavity , mainly the cavity.
Located on the lower side of the bed, the activity of the powder is divided into a blunt powder accumulation layer, and not only the crushed material and the returned coarse powder guided by the air flow of the nozzle, but also the particles in the accumulation layer due to the suction force of the jet flow. The particles are pulled out, accelerated, crushed by the mutual collision and frictional action of the powder particles, and brought into a classification chamber when finer, and the rest is returned to the deposited layer. At this time, due to the local negative pressure formed by the jet flow blown out from the injector / nozzle, the crushed material in the screw case is subjected to the suction action, and the static pressure inside the crushing chamber is slightly lower than that of the outside (for example, 30 to 4).
Even if it is high (about 0 cm water column), prevent the crushed material from being blown out from the crushed material hopper.

[0018]

1 to 8 show an embodiment of the present invention. FIG. 1 shows the main components of the present invention. The crushed material supply device A is attached to the horizontal portion 1a of the frame, and one end thereof is engaged with the injector nozzle B ₁ . The crushing chamber B in which the powder is crushed has a circulation means for transporting the crushed material and returning the coarse powder in the upper part thereof, and above the crushing chamber B, a classification chamber C including an air flow preliminary swirling chamber 29. Is a vertical flange 2
It is screwed to the vertical surface 1b of the frame by 3a. The classification chamber C is connected to the crushing chamber B by a connecting bolt, and the fine powder outlet 24 of the classification chamber C is connected to a dust collector and a suction blower by a duct (not shown). The crushing chamber B is provided with a counter nozzle B ₂ facing the injector nozzle B ₁ , and each of these nozzles B ₁ and B ₂ is connected to a gas pressure source ( Compressor).

The crushing case 2 forming the crushing chamber B is shown in FIG.
It consists of a horizontal cylinder with one end open as shown in Fig. 2, and the opening at one end (right side in the figure) is the case cover 2.
It is closed by a and the injector nozzle B ₁ is provided on the outside thereof. The other end (the left side in the figure) of the crushing case 2 is a bottom plate 2b having an inclined surface, and the counter nozzle B ₂ is provided at an inclined portion of this bottom plate 2b.
Is provided. Center line of the counter-nozzle B ₂ has a center line and the intersection angle α 1 of the injector nozzle B ₁
They intersect at an intersection 2c so as to form an angle of 40 ° to 160 °. The inclined surface of the bottom plate 2b is inclined so that the intersection 2c is substantially equidistant from the _two nozzles B ₁ and B ₂ . Above the intersection 2c, a square tube connected to the classification chamber C is projected from the crushing case 2, and the air flow preliminary swirl chamber 2 of the classification chamber C is provided.
A crushed material transport passage 2d leading to 9 is formed.

In addition, another square tube juxtaposed with the square tube is projected from the crushing case 2, and from under the double cylinder formed in the classification chamber C, near the tip of the counter nozzle B _2. The coarse powder return passage 2e is formed toward the. A branch pipe 2f is projected obliquely upward to a part of the body of the crushing case 2, and a level sensor 4 (for example, a commercially available product such as a vibrating bar type or an electrostatic capacitance type is used) is attached to the cover 3 of the body. , Branch pipe 2
A protective plate 5 for preventing collision with powder scattered from the crushing chamber B side is placed in the inside of f on the center line side of the crushing case 2, and a sensor is provided outside the center of the crushing chamber B divided by the protective plate 5. The detection unit 4a is provided obliquely downward. The level sensor 4 detects the boundary surface between the hollow portion and the powder deposit layer due to the jet in the crushing chamber B, and controls the crushing supply motor. In FIG. 2, a broken line 6 that crosses the cross section of the crushing case 2 shows an example of a boundary between a hollow portion having a low powder concentration through which a gas jet passes and a deposition layer where the powder is not active.

Referring to FIG. 3, the injector nozzle B
₁ will be described. The flanged tubular sheet 7 fitted in the central opening of the case cover 2a is screwed into a case .
Is fixed by the nozzle case 8 is fixed to the over scan cover 2a. Inside the nozzle case 8, a hollow spindle 9 having a conical surface with a cone angle γ ₂ (≈24 °) formed at the tip is screwed at its base end side to a threaded portion 8 a of the nozzle case 8 to lock. It is fixed by the nut 10. The inner surface of the tubular sheet 7, a first conical surface having an anti-crushing chamber larger cone angle than the cone angle gamma _{2 2} on the side of β (≒ 90 °),
A cone angle γ smaller than the cone angle γ ₂ near the crushing chamber B
_A second conical surface having a diameter of ₁ (≈16 ° to 18 °) is continuously formed, and a laval having a "throat" 7a through which compressed gas passes in a space space between the conical surface at the tip of the hollow spindle 9 and the conical surface. A tube is formed.

The back surface of the tubular sheet 7 and the hollow spindle 9
The annular space 8c formed by the central cylindrical surface of the nozzle case 8 and the nozzle case 8 is a retention place of the compressed gas introduced from the screw hole 8b provided on the peripheral surface of the nozzle case 8, and is a nozzle hole (Laval tube). The compressed gas is uniformly blown out from the entire area of. When the hollow spindle 9 screwed into the nozzle case 8 is rotated, the hollow spindle 9 moves back and forth with respect to the nozzle case 8, and the two conical surfaces of the tubular sheet 7 and the conical surface at the tip of the hollow spindle 9 are moved. Since the cross-sectional area of the "throat" 7a formed by is increased or decreased, the amount of compressed gas blown from the injector nozzle B ₁ into the crushing chamber B can be adjusted by moving the hollow spindle 9 back and forth.

The crushed material supply device A will be described with reference to FIGS. 3 and 1. The cylindrical screw case 12 is fixed to the horizontal portion 1a of the frame by screwing the foot 12a. In the upward opening 12b provided on the base end side of the screw case 12, the crushed material hopper 1
3 are coupled by a coupling 13a. The tip of the screw case 12 has a cylindrical hole 9 in the hollow spindle 9.
It is inserted loosely with respect to a, allows the hollow spindle 9 to move forward and backward, and, together with the opening 12c in the upper part of the cylinder provided in the screw case 12, provides a passage for attracting secondary gas when a jet flow is generated. A bearing case 15 having a bush 14 inserted therein is screwed to the base end of the screw case 12. In the cylindrical hole of the screw case 12, the screw shaft 16 whose end reaches the inside of the conical hole 9b of the hollow spindle 9 is laterally inserted. Screw shaft 1
The shaft neck on the base end side of 6 is the bearing case 1 by the bush 14.
5, the shaft neck portion protruding from the bearing case 15 has a pulley 17 which is integrally rotated by a key 16a.
Is fixed by the nut 16b. Screw shaft 16
Torque is transmitted from a pulley fixed to a motor shaft (not shown) to the pulley 17 via a belt.
When the screw shaft 16 is driven, the crushed material is supplied from the crushed material hopper 13 to the crushing chamber B through the screw case 12 and the through hole of the hollow spindle 9.

The counter nozzle B ₂ will be described with reference to FIG. The flanged tubular sheet 18 fitted in the hole of the bottom plate 2b of the crushing case 2 is fixed by a nozzle case 19 attached to the bottom plate 2b of the crushing case 2 with a bolt 20. Inside the nozzle case 19, a needle 21 having a conical surface with a cone angle γ ₂ ′ (≈12 °) formed at the tip is provided with a screw 19 of the nozzle case 19 at the base end side.
It is screwed with a and fixed by the lock nut 22.
On the inner surface of the tubular sheet 18, a conical surface having a conical angle β (≈90 °) larger than the conical angle γ ₂ ′ on the side opposite to the grinding chamber, and a cylindrical surface closer to the grinding chamber B than the conical surface are continuously formed. A Laval tube having a "throat" 18a through which a compressed gas passes is formed in a space between the tip of the needle 21 and the conical surface.

An annular space 19c formed by the back surface of the tubular sheet 18, the needle 21 and the inner surface of the nozzle case 19 is filled with compressed gas introduced from a screw hole 19b provided in the peripheral surface of the nozzle case 19. The compressed gas is uniformly blown out from the entire area of the nozzle hole (Laval tube) at the retention place. When the needle 21 screwed into the nozzle case 19 is rotated, the needle 21
Moves back and forth with respect to the nozzle case 19, and the tubular sheet 18
In order to increase or decrease the cross-sectional area of the "throat" 18a formed by the boundary transitioning from the conical surface to the cylindrical surface of the needle and the conical surface at the tip of the needle 21, the needle 21 moves back and forth from the counter nozzle B ₂ to the grinding chamber B. The amount of compressed gas blown in can be adjusted.

The classification chamber C will be described with reference to FIGS. The classification case 23 is screwed to the vertical surface of the frame 1b by a flange 23a provided at one end opening, and the other end is screwed to a classification case cover 25 having a fine powder outlet 24 formed in the center. To be done. Classification case 2
The cylindrical body of 3 has a central opening 23c near the frame 1b.
Is provided with a partition wall 23b. Center of partition wall 23b
A bearing case 28 holding the drive shaft 27 is provided in the opening 23c.
Part of the bearing is inserted from the outside, and
The partition wall 23b is provided from the outside at the portion of the flange 28a provided.
It is screwed to. Bearing case 28 to classification case
In the portion of the drive shaft 27 protruding into 23,
All rotating type impellers 26 are attached, and the classification case
An opening 23d, which is deflected with respect to the axis of the classification case 23, is provided below the bearing case 28 inside the 23, corresponding to the crushed material transport passage 2d of the crushing case 2.
The outer surface of the body, the inner surface of the classification case 23 and the partition wall 23b form an air flow preliminary swirl chamber 29 in an annular space.

An inner cylinder 30 that concentrically surrounds the rotary impeller 26 is detachably attached to an extension of the inner surface of the classification case 23 that constitutes the air flow preliminary swirl chamber 29, and a large diameter classification located outside the inner cylinder 30. A double cylinder is formed together with the large diameter portion 23e of the case 23. Below the large diameter portion 23e of the classification case is a chute shape, and the opening 2 corresponding to the coarse powder return passage 2e is formed.
3f is provided. The classification work is performed between the double cylinder and the rotary impeller 26. One end of the rotary impeller 26 is
Circular bottom surface 2 having boss 26a into which drive shaft 27 is fitted
It has a hollow cylindrical shape that is closed by 6b and the other end is open. On the outer peripheral surface of the rotary impeller 26, a large number of stepped blades 31 arranged in parallel with the axial direction are provided at equal pitches along the circumference, and the outside of the blades 31 is fixed to have a large diameter from the inflow side of the air flow. A cylindrical portion 26d and a small diameter cylindrical portion 26e are provided. In the large-diameter cylindrical portion 26d, an intake passage 26c penetrating the outer peripheral surface of the rotary impeller 26 is formed between the adjacent blades 31, 31, as shown in FIG.

Further, the stepped-down portions 31a of the blades 31 having different steps are provided.
Has an inner and outer diameter equal to this and forms a small-diameter cylindrical portion 26e together with the rectangular ring 31b connected to the step-down portion 31a. The circular opening of the rectangular ring 31b corresponds to the fine powder outlet 24 provided in the classification case cover 25. On the inner side of the classification case cover 25, the classification case cover 2
Annular partition plate 32 having a primary gas reservoir <br/> or Ri 3 2a leading to the gas introducing hole 25a provided on the 5 is screwed,
An axial gap 30a is formed between the inner surface of the partition plate 32 and the open end of the inner cylinder 30 to provide a place where the air stream containing the coarse powder after classification makes a U-turn and is exhausted. In addition, the blade 3 that moves from the large-diameter cylindrical portion 26d to the small-diameter cylindrical portion 26e.
A primary-side clearance δ ₁ is formed between the slope 31c formed by the outer circumference of No. 1 and the inner peripheral conical surface formed by the partition plate 32.

An annular groove-shaped secondary gas reservoir 33 is formed between the rectangular ring 31b and the rectangular ring 31b on the inner peripheral surface of the partition plate 32 which faces the outer peripheral surface of the rectangular ring 31b. Front and rear partition plate 32 inner peripheral surface and square ring 3
A narrow secondary side gap δ ₂ is formed between the outer peripheral surface of 1b. The length of the gap portion length 1 ₁ of the closest secondary side clearance [delta] ₂ to the inclined surface 31c of the blades 31 of the impeller 26 is shorter than the opposite side of the secondary-side gap [delta] ₂ length 1 _2. These gaps δ ₁ ,
The classification chamber C is communicated with the fine powder outlet 24 by δ ₂ and the secondary gas reservoir 33. The primary gas reservoir 32a and the secondary gas reservoir 33 are communicated with each other by a large number of flow passages 34 provided at equal intervals in the circumferential direction, and the gas introduction holes 25a are provided.
The sealing gas flowing in from is uniformly distributed to the secondary gas reservoir 33. During operation, the sealing gas is constantly blown from the secondary gas reservoir 33 through the primary side gap δ ₁ and the secondary side gap δ ₂ , and is contained in the air flow before classification in the gap between the rotary impeller 26 and the partition plate 32. This prevents the powder from entering and prevents the powder from leaking through the gaps δ ₁ and δ ₂ to the fine powder outlet 24 side.

The boss 26a of the rotary impeller 26 has a shaft neck 27c of the drive shaft 27 which projects horizontally from the bearing case 28.
Part of the bearing case 28 and the inner ring of the bearing 35a in the bearing case 28 is pressed by the spacer 36 to position the rotary impeller 26, and at the same time, to rotate the rotary blade. The torque required to rotate the vehicle 26 is transmitted. 37 is a cover that presses the outer race of the bearing 35a held in the bearing case 28, the counter-bearing side of the cover 37, the width 1 ₃ of visor 37e covering the outer periphery of the circular bottom surface 26b of the rotary impeller 26 is provided Has been. The cover 37 forms an annular gas reservoir 37c on the side facing the rotary impeller 26. The center-side end face of the plenum 37c, the end face of the outer periphery toward the respectively narrower end face gap [delta] ₅ between the circular bottom surface 26b of the impeller 26 [delta] ₄
To form. Similarly, the eaves 37e of the cover 37 forms a narrow outer peripheral gap δ ₃ with the rotary impeller 26.

A part of the bearing case 28 is a flange 28.
An L-shaped gas passage 28b passing through a is provided, and an opening end of the gas passage 28b on the cover 37 side is covered by a gas passage 37a provided at a corresponding position of the cover 37.
Of the gas passage 37 while communicating with the gas reservoir 37c of
Another gas passage (branch passage) 37b branched from 7a and the outer peripheral surface of the spacer 36 near the bearing 35a and the cover 3
7 communicates with the gas reservoir 37d formed by the inner surface of the hole 7. During operation, the compressed gas accumulated in the large gas reservoir 37c moves toward the outside of the rotary impeller 26 from the narrow outer peripheral gap δ ₃ between the rotating rotary impeller 26 and the eave 37e of the stationary cover 37. Is blown out. Further, a part of the compressed gas passes through the branch pipe branch passage 37b of the cover 37, and from the gas reservoir 37d to the outer periphery of the spacer 36 and the cover 37.
Through the narrow gap portion formed with the inner surface of the hole, and further through the end surface gap δ ₅ to communicate with the gas reservoir 37c, the powder (foreign matter) around the rotary impeller 26 is prevented from entering the inside of the bearing 35a. To prevent.

The drive shaft 27 includes the bearing 35a and another bearing 35b fixed to the drive shaft 27 by a nut 38.
Is supported by the bearing case 28 via the drive shaft 27.
A pulley (not shown) is keyed to the shaft neck 27d on the outer side of the shaft neck, and the torque required for the rotation of the drive shaft 27 is transmitted via the belt by the pulley fixed to the motor shaft.

Next, the operation of the apparatus will be described. 1) Gas reservoir 37 for bearing 35a of drive shaft 27 that rotates rotary impeller 26 from the compressed gas source for sealing gas
c, 37d and the gas pool 3 for the gap between the inner peripheral surface of the partition plate 32 of the classification chamber C and the rectangular ring 31b of the rotary impeller 26.
2a, 33 to protect the bearing 35a, and the classification chamber C
Measures are taken to prevent the coarse powder from leaking from the outlet to the fine powder outlet 24. 2) The rotary impeller 26 is accelerated to a predetermined rotation speed for operation. 3) Activate the suction blower to reduce the pressure inside the crushing chamber B. 4) Charge the compressed gas set by the pressure regulator into the injector nozzle B ₁ and the counter nozzle B ₂ . 5) The screw shaft 16 is driven by starting the motor for supplying crushed material. 6) Inside the grinding chamber B, the injector / nozzle B ₁
Is attracted to the gas jet ejected from the screw case 1
The crushed material is brought in from 2 and the powder in the accumulated layer in the crushing chamber B, which remains from the previous work, is sucked and accelerated by the jets blown from both nozzles B ₁ and B ₂ , and the crushing work is performed. Begins. At this time, the static pressure inside the crushing chamber B becomes a steady value (higher than the outside). 7) At the same time, the finely ground pulverized product is conveyed to the classification chamber C by the air flow depressurized by the pulverization, and is classified into fine powder and coarse powder by the rotary impeller 26, and the fine powder is put on the air flow by the suction blower. And is conveyed from the fine powder outlet 24 to the dust collector and collected. 8) The coarse powder is immediately returned from the classifying chamber C to the crushing chamber B, and the crushing is repeated again. 9) During the crushing operation, the boundary surface between the powder deposit layer in the crushing chamber B and the cavity formed by the jet is monitored by the level sensor 4, and the feed rate of the pulverized material is set higher than the production rate of the fine powder. When the boundary surface rises to reach a predetermined level, the level sensor 4 operates, and the timer for interlocking stops the motor for supplying the pulverized material after a preset time to interrupt the supply of the pulverized material. After that, when the boundary surface is lowered to a predetermined level by continuing the crushing, the level decrease is detected by the level sensor 4. In parallel with this, the crushed material supply motor is activated, and the supply of crushed material is automatically restored. This operation continues until the work is stopped. 10) Meanwhile, powder in the grinding chamber B and the classification chamber C,
The behavior related to the air flow is as described in the section “Action”.

[0034]

Since the present invention is configured as described above, it has the following effects. In the airflow type fine pulverizer according to claim 1,

(1) In the injector / nozzle, the gas passage through which the air flow emitted from the gas source passes and the passage through which the crushed material passes are distinguished from each other, and the hollow spindle in which the crushed material is carried on the center line of the injector nozzle. Is provided as a first core body, a tubular tubular sheet is provided so as to surround the first core body, and an annular portion formed in a gap between the core body and the tubular sheet surrounding the core body is a gas passage. This gas passage is provided with a throat portion whose cross-sectional area is once reduced along with the flow of gas and then expanded, and compressed gas is introduced from the outside of the crushing chamber of this gas passage toward the inside of the crushing chamber. Therefore, the speed of passage of the pulverized material supplied from the hollow spindle may be sufficiently slow, compared to the case where the pulverized material passes through the accelerating pipe (or nozzle) at high speed together with the gas emitted from the gas source as in the conventional technique. hand, Wear of wood is significantly less, it is possible to eliminate a disadvantage of contaminating the 砕製 products. In addition, even if the static pressure inside the crushing chamber is slightly higher than the external environment, the local negative pressure created by the jet flow from the gas passage of the injector / nozzle prevents the crushed material from being blown out from the crushed material hopper. To be done. (2) Moreover, the injector nozzle and counter
Since the nozzle is formed as an annular nozzle, the hollow gas jet that comes out of the annular nozzle contacts the powder layer with a large surface area compared to the case of the gas jet that comes out of the single-hole nozzle. The chance of aspiration and crushing can be increased. (3) Further, since the counter nozzle is installed in the crushing chamber so as to face the center line of the injector nozzle at an obtuse angle, the crushed material from the injector nozzle is injected into the counter nozzle. There is no fear, and wear of the counter nozzle due to injection is prevented.

In the airflow type fine pulverizer of claim 2, (1) the passage of the airflow for transporting the pulverized material from the pulverization chamber to the classification chamber is deflected with respect to the cylindrical body forming the extension of the inner cylinder of the classification chamber. Since they are communicated with each other, the air flow carrying the pulverized material is given a preliminary swirling motion before entering the inner cylinder. Therefore, around the rotary impeller for classification, the sorting action by the centrifugal force of the powder works properly from the axial inlet side of the rotary impeller, and the coarse powder continues to flow from the outlet side of the pulverized material transport passage. Since the particles move together in the vicinity of the wall of the cylinder, coarse powder and coarse particles are prevented from being mixed in the fine powder of a desired size. (2) The resistance received when the air flow carrying the fine powder enters the rotary impeller of the classification chamber is almost the same regardless of where it enters from the circumferential surface of the rotary impeller. The velocity of passing through the intake passage of the rotary impeller is uniform with respect to the entire outer peripheral surface on the intake side of the rotary impeller. As a result, in the vicinity of the rotary impeller, the relationship between the conveying force of the air flow that conveys the particles and the centrifugal force due to the swirling airflow of the rotary impeller is approximately the same at any position in the axial direction of the blade of the rotary impeller. be able to. Therefore, since the limit particle diameters in the outer peripheral portion of the rotary impeller are almost the same, it is possible to efficiently produce a uniform product having a narrow particle size distribution width. (3) By the double cylinder provided around the rotary impeller, the swirling airflow around the impeller is rectified by being clearly separated from the airflow containing the coarse powder that exits from the classification chamber, so that the coarse powder rotates. It is possible to efficiently remove the impeller from the classification chamber without approaching the impeller, and reduce the load current required to operate the rotary impeller. (4) Since the crushed material transportation passage is above the intersection of the center lines of both nozzles, the crushed material can be welcomed from the crushing chamber to the preliminary swirl chamber by being placed on the ascending air current depressurized by the crushing work. Further, since the coarse powder returning passage has an outlet near the tip of the counter nozzle, the coarse powder can be conveyed from the classification chamber to the pulverization chamber without delay.

In the air-flow type fine pulverizer of claim 3, since the cross-sectional area of the passage through which the gas flows in the annular nozzle is formed in the Laval tube which is sharply reduced at the beginning and then gradually enlarged, it is jetted from the nozzle. The gas jet is accelerated to a speed around the speed of sound, and the sucked powder can be blown off at high speed to promote crushing.

In the airflow type fine pulverizer of claim 4, since the hollow spindle or the needle is attached to the tubular sheet so as to be able to advance and retract, the core of these nozzles is advanced and retracted with respect to the tubular sheet of the nozzle. As a result, the opening area of the "throat" of the nozzle can be easily and steplessly adjusted, so that a wide range of gas source (compressor) can be accommodated by the nozzle having the same specifications. Further, by narrowing down the opening area of the "throat" to limit the amount of gas input and by taking the classification impeller at the maximum rotation speed, it is possible to obtain a crushed product of ultrafine powder. Furthermore, if the surface of the nozzle that is in contact with the air flow becomes worn due to long-term use, the opening area of the "throat" should be maintained at a predetermined size by advancing the core of the nozzle toward the grinding chamber. You can

In the air flow type fine pulverizer of claim 5, in the gap between the inner peripheral surface of the partition plate and the outer peripheral surface of the rectangular ring portion which is the terminal end of the classifying impeller, the gas reservoir is directed toward the classifying surface of the impeller. The sealing gas is blown out, which prevents the coarse powder from leaking from the classification chamber toward the fine powder discharge port in a short-circuiting manner, and prevents coarse crushing and mixing above the classification point in the crushed product taken out of the device. be able to.

In the airflow type fine pulverizer according to the sixth aspect, since the crushed material supply device including the screw shaft is attached to the opening of the hollow spindle constituting the injector nozzle on the side opposite to the pulverization chamber, the screw shaft is attached. Ru good to the rotation of the
The crushed material by transporting action to feed transfer to the interior of the hollow spindle from crushed material hopper, it is possible to supply the crushed material into the grinding chamber interior in cooperation with the suction effect of the jet gas blown from the injector nozzle. Moreover, since the crushed material supply device containing the screw shaft is inserted loosely, if the hollow spindle is moved back and forth in the axial direction to change the opening area of the throat of the injector / nozzle, the crushed material is crushed from the injector / nozzle. The amount of compressed air blown into the chamber can be adjusted to change the amount of crushed material supplied to the crushing chamber.

[Brief description of drawings]

FIG. 1 is a front view showing a part of an embodiment of the present invention in section.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged vertical sectional view of an injector / nozzle portion.

4 is a sectional view taken along line 1V-1V in FIG .

FIG. 5 is a vertical sectional view of a counter / nozzle portion.

6 is a sectional view taken along line V1-V1 of FIG .

FIG. 7 is an enlarged sectional view of a base end side of a rotary impeller .

FIG. 8 is an enlarged cross-sectional view of a main part on the tip side of the rotary impeller .

[Explanation of symbols]

2d crushed material transport passage 2e coarse powder return passage 7,18 tubular sheet 7a, 18a throat 8c, 19c retention location of compressed gas 9 hollow spindle 12 screw case 13 crusher hopper 16 screw shaft 21 needle 23 classification case 24 fine powder outlet 25 Classification Case Cover 26 Classification Rotor (Rotating Impeller) 26d Large Diameter Cylindrical Part 26e Small Diameter Cylindrical Part 27 Drive Shaft 29 Air Flow Pre-Swirl Chamber 30 Inner Cylinder 31 Blades 31b Square Ring 32 Annular Partition Plate A Grinding Material Supply B B Grinding Chamber B ₁ injector / nozzle B ₂ counter / nozzle C classification chamber δ ₁ primary side gap δ ₂ secondary side gap

Claims (6)

[Claims] 1. A crushed material supplied to a crushing chamber through an injector nozzle is crushed by an injector nozzle and a counter nozzle, and fine powder having a certain particle size or less in the crushed product is placed in a classification chamber above the crushing chamber. In an air flow type fine pulverizer which classifies by a classifying means and takes it out of the device, and returns coarse powder of a certain size or more to a crushing chamber by a circulating means and repeats crushing again, the counter nozzle is located at the center line of the injector nozzle. attached to the grinding chamber and opposite to intersect at an obtuse angle against
Crushed material on the center line of the injector nozzle.
A hollow spindle in which is carried is arranged as the first core,
In addition, the needle has a second core on the center line of the counter nozzle.
A cylindrical body that is arranged as a body and surrounds each of the first core body and the second core body.
-Shaped tubular sheet is provided, and each core and the tubular sheath surrounding it are
The annular part formed in the gap with the port is the gas passage.
In the gas passage, the cross-sectional area once contracted along the gas flow
It is equipped with a throat part that will be expanded later, outside the grinding chamber of this gas passage.
Air-flow type fine pulverizer in which compressed gas flows from the side toward the inside of the pulverization chamber . 2. The classifying means is a rotary impeller having a closed end face side fixed to a drive shaft and having a large number of strip-shaped blades parallel to the axis on an outer peripheral surface, wherein the rotary impeller is a large-diameter cylinder. Has a different-diameter cylindrical outer shape having a portion and a small-diameter cylindrical portion, an opening is formed by a square ring at the end of the small-diameter cylindrical portion, and an annular partition plate is provided close to the outer periphery of the square ring, A classification case cover with a fine powder outlet is attached to the opening side of the classification case that houses the rotary impeller.
The classification chamber is formed by a double-cylindrical housing that surrounds the rotary impeller, and forms an extension surface of the inner cylinder of the double cylinder on the front side of the closed end surface where the rotary impeller is attached to the drive shaft. An air flow preliminary swirl chamber is provided by the cylindrical housing, and the powder circulating means is crossed so that the counter nozzle forms an obtuse angle with respect to the center line of the injector nozzle.
From the upper side of this intersection point toward the air flow preliminary swirl chamber formed in the classifying means, formed between the crushed material transport passage which is deflected and connected to the axis of the rotary impeller and the double cylinder of the classifying chamber. 2. An air flow type fine pulverizer according to claim 1, wherein the annular space part is formed by a coarse powder returning passage connected so as to be close to one end of a nozzle attached to the pulverizing chamber. 3. An injector nozzle and a counter
The nozzle has a conical surface that gradually shrinks toward the crushing chamber at the tip of the hollow spindle or needle that forms these cores, and the inner surface of each tubular sheet that faces the conical surface of these cores is Is a first conical surface having a cone angle larger than the cone angle of the core body that contracts from the compressed gas introduction side toward the crushing chamber side, and a second cone surface having a cone angle smaller than the cone angle of the core body, or The cylindrical surface is continuously formed, and a throat portion having a minimum annular cross-sectional area is formed in an intermediate portion of a gap between the inner surface of these tubular sheets and the outer surface of each core body. Airflow type fine pulverizer according to 2. 4. A hollow spindle or needle having a conical surface formed at its tip is attached to each tubular seat engaged with the tip by a screwing or other means so as to be able to move forward and backward. Air flow type fine pulverizer described in. 5. The classifying case is provided with a partition plate on the inner surface of the classifying case cover attached to the opening, and the inner peripheral surface of the partition plate is the end of the small diameter cylindrical part of the rotary impeller as the classifying means. Which is held in close proximity to the outer peripheral surface of the rectangular ring, and between the inner peripheral surface of the partition plate and the outer peripheral surface of the rectangular ring, an annular gas pool connected to the compressed gas source and this gas pool are classified. The airflow type fine pulverizer according to any one of claims 1 to 4, wherein a primary side gap and a secondary side gap which are respectively communicated with the chamber and the fine powder outlet are provided. 6. The pulverized material supply device including a screw shaft is loosely inserted in the opening of the hollow spindle constituting the injector nozzle on the side opposite to the crushing chamber. Airflow type fine crusher.