JPH0261319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wind classifier that classifies granules into coarse particles and fine particles using centrifugal force in a solid-gas mixed fluid flow.

[Conventional technology]

This type of wind classifier that has been used in the past can be roughly divided into forced vortex type and free vortex type.

In the forced vortex type, the solid-gas mixed fluid introduced into the container is passed from the outside to the inside of a rotating multi-blade fan-shaped blade rotor installed at the fluid outlet, and sucked from the outside of the container. At this time, due to the equilibrium relationship between the outward force due to the centrifugal force applied to the particles and the inward force due to the inward airflow due to the attraction force from the outside, coarse particles larger than a certain boundary particle size will move outward. The small particles are discharged and collected at the bottom of the container, and the small particles enter the vane rotor and are sucked and collected by an external fan.

Free-vortex types, such as cyclones,
Due to the swirling flow of the fluid in the container caused by suction or pressure from the outside, the centrifugal force exerted on the particles in the fluid causes coarse particles larger than a certain boundary particle to move outward, reducing the low velocity of the swirling flow near the peripheral wall. The small particulates are collected from the bottom of the container by being allowed to fall in the area, and small particles are discharged from the top along with the airflow and captured separately.

[Problem that the invention seeks to solve]

However, these conventional methods have low classification accuracy, and for example, it is difficult to classify fine particles of 10 μm or less, which has been a problem.

The present invention aims to solve this problem, and aims to provide a wind classifier that can perform accurate and stable classification.

[Means for solving problems]

The present inventor has conducted many research experiments in order to achieve the above object, and the present invention has been made based on the knowledge obtained at that time.

That is, in the forced vortex type, in the classification section, which is the area where the classification action is performed by the balanced relationship between the outward force due to centrifugal force and the inward force due to suction airflow,
The rotor blades collide with the gas and particles in the mixed liquid, giving them a tangential velocity, so the flow in this classification section is extremely turbulent, and this is due to the delicate balance between the outward force and inward force mentioned above. It was found that it was difficult to improve accuracy because classification was performed within this disordered area.

In addition, in the free-vortex type, a stable classification area cannot be obtained due to the frictional force with the fixed peripheral wall, and classification is performed in an unstable area based on the delicate balance between outward force and inward force. Therefore, it was found that it was difficult to improve the accuracy.

As a means for solving the above-mentioned problems, the present invention provides a wind classifier that introduces a solid-gas mixed fluid into a rotating container and classifies coarse particles and fine particles by centrifugal force. is provided with a solid-gas mixed fluid suction path, a coarse particle discharge path, and a discharge path for gas accompanied by fine particles, and an annular classification section is formed inside the peripheral wall of the rotating container, and the solid-gas mixed fluid suction path includes the An impeller that rotates at approximately the same speed as the rotating container is provided with an impeller inlet facing a suction path and an impeller outlet end facing the classification section, and the discharge path communicates with an inner peripheral edge portion in the classification section. The coarse particle discharge passage is provided in communication with an outer peripheral portion of the classification section through a discharge port provided intermittently on a wall of the rotating container at the periphery of the classification section. A classifier as a second invention,
In a wind classifier that introduces a solid-gas mixed fluid into a rotating container and uses centrifugal force to classify coarse particles and fine particles,
The rotating container is provided with a solid-gas mixed fluid suction path, a coarse particle discharge path, and a gas discharge path accompanied by fine particles, and an annular classification portion is formed inside the peripheral wall of the rotating container, and the solid-gas mixed fluid suction path is provided with an annular classification section. A first impeller that rotates at approximately the same speed as the rotating container is provided with the impeller inlet facing the suction path and the blade outlet end facing the classification section, and the discharge path is located inside the classification section. The coarse particle discharge passage is provided in communication with the inner peripheral edge portion of the rotating container, and the coarse particle discharge path communicates with the outer peripheral edge portion of the classifying portion through discharge ports provided intermittently in the rotating container wall at the peripheral edge of the classifying portion. An intake passage is provided in an annular manner and communicates with the coarse particle discharge passage, and the intake passage includes a second impeller that rotates at approximately the same speed as the rotating container; It is an object of the present invention to provide a wind classifier characterized by being equipped with a mouth area adjusting member.

[Effect]

In the first aspect of the present invention, by having the above-described configuration, the solid-gas mixed fluid is supplied to the classification unit by the first impeller at approximately the same tangential speed as that of the rotating container.

Since the rotating container is rotating in the classification section, there is almost no relative tangential velocity between the mixed fluid and the rotating container, and the gas and particles in the mixed fluid are stable with little disturbance not only in the tangential direction but also in the radial direction. can be maintained.

In the classification section, particles in such a stable state within the classification area are subjected to an outward force due to centrifugal acceleration of a substantially uniform magnitude, and classification is performed in a balanced relationship with an inward force due to a stable air flow.

The classified coarse particles are discharged from the coarse particle discharge passage, and the fine particles are discharged together with gas from the discharge passage.
Classification of coarse particles and fine particles is performed.

The second invention has the above-mentioned configuration, and in addition to the effects of the first invention, in the classification section, a stable particle flow with little turbulence, a stable gas flow, and a substantially uniform centrifugal acceleration can be achieved. Based on this, the boundary particle size of the particles to be classified is adjusted.

In other words, the second impeller sucks and supplies regulating gas into the coarse particle discharge passage communicating with the outer periphery of the classification section, with a variable air volume. Since the fluid is supplied by the second impeller at a tangential velocity that is almost the same as the tangential velocity of the flow formed in the discharge path and the classification section, it does not affect the tangential velocity of the mixed fluid flow in the classification section. do not have.

Furthermore, since adjusting the boundary particle size by adjusting the air volume does not cause the wind speed in the classification section to drop below the required level, accurate and smooth classification is not hindered.

When it is desired to increase the size of the boundary particles to be classified, the area of the intake port is increased using the intake port area adjusting member to increase the amount of air introduced into the coarse particle discharge path. Then, the flow rate of air that flows into the classification section through the discharge port and toward the discharge passage increases, so even larger particles are entrained in the gas and discharged from the discharge passage, and therefore coarse particles discharged from the coarse particle discharge passage increase. The diameter will be larger than before. When it is desired to reduce the particle size at the boundary of classification, the amount of air introduced into the coarse particle discharge channel can be reduced.

〔Example〕

Embodiments of the present invention will be described using the drawings.

The casing 1 includes a rotating container 2 therein, and is fixed to a base 4 via legs 3. The rotating container 2 is fixed to the upper end of a shaft 5 that penetrates the bottom wall of the casing 1, and the shaft 5 is connected to the base 4 through a bearing 6.
is rotatably supported. The lower end of the shaft 5 is provided with a drive shaft 7 and is connected to a drive mechanism (not shown).

The rotating container 2 includes a suction passage 8 for a solid-gas mixed fluid, a discharge passage 9 for a gas accompanied by fine particles, and a discharge passage 10 for coarse particles, and a classification section 11 is formed inside the peripheral wall.

The suction path 8 consists of a volute casing 12 and a vertical pipe 13, which are fixed by appropriate means, and the outlet of the vertical pipe 13 is connected to the inlet of the first impeller 14.

The first impeller 14 only needs to be provided so that it rotates at approximately the same speed as the rotating container 2 and the outlet end of the blade faces the classification section 11. In this embodiment, the bottom wall portion of the rotating container 2 is used as the main plate 15 and A first impeller 14 is used, which is composed of a main plate 15, blades 16, and side plates 17, with the shaft 5 of the rotating container 2 as the rotation axis, and the outlet end of the blade 16 faces the classification section 11.

The discharge section 9 is formed of a volute casing 18 that is fixed and connected to the upper opening of the rotating container 2 by appropriate means so as not to rotate together with the rotating container 2, and is connected to the inner peripheral edge of the classifying section 11, that is, the rotating container 2. It is provided in communication with the central part of 2. A current plate 31 is provided in the flow path from the inner peripheral edge of the classification section 11 to the volute casing 18.

The discharge passage 10 is connected to the classification section 1 through an appropriate number of discharge ports 19 provided intermittently on the peripheral wall of the rotating container 2 surrounding the classification section 11.
It is provided in communication with the outer peripheral edge part of 1.
The rotating container 2 is housed inside the casing 1 so as to form an annular discharge passage 10 on its outer periphery. The casing 1 has a shape in which a coarse particle collecting groove 22 is formed below the outer peripheral edge in the discharge passage 10 via a scattering prevention plate 21 having a large number of slits 20 radially.
A coarse particle outlet 23 is provided in the coarse particle collection groove 22 .

The casing 1 further includes an intake passage 24 that sucks air into the inner peripheral edge portion of the discharge passage 10.
In this embodiment, an air intake passage 24 is formed with an interval between the rotating container 2 and the bottom of the casing 1.
An intake port 25 is provided at the bottom of the casing. A second impeller 26 that rotates at approximately the same speed as the rotating container 2 is provided in the intake path 24, with the impeller inlet facing the intake port 25 and the impeller outlet facing the discharge path 10. . In this embodiment, a main plate 27 that also serves as the main plate 15 of the first impeller 14, and a blade 2
8. A side plate 29 formed of a conical portion of the casing 1, and an impeller 26 having a shaft 5 as a rotating shaft are used. The intake port 25 is provided with an opening area adjusting member 30.

In the figure, 32 is a lock nut, 33 is a cover, and 34 is a suction pipe. 35 is a coarse particle discharge pipe, and the outlet thereof is provided with a rotary feeder or a damper for discharging coarse particles. 36 is a discharge pipe, and a bag filter for capturing particulates is provided at the outlet.

Thus, the solid-gas mixed fluid is sucked into the first impeller 14 and sucked in through the suction path 8 . At this time,
Due to the action of the volute casing 12, the fluid flows in the vertical pipe 13 as a swirling flow, so that the aggregated particles collide with the walls of the vertical pipe, are loosened by friction, and are sucked in. Furthermore, since the rotational speed of the blades 16 and the rotational speed of the fluid near the inlet of the first impeller 14 become similar, wear of the blades 16 can be reduced.

In the first impeller 14, the solid-gas mixed fluid is pressurized and given a swirling force, but during this time it is further loosened and becomes easier to classify.

The solid-gas mixed fluid discharged from the first impeller 14 to the classification section 11 is subjected to the above-mentioned action, and coarse particles are discharged through the discharge port 19 into the discharge passage 10 and fall into the coarse particle collecting groove 22. The coarse particles are appropriately taken out from the discharge pipe 35 through the coarse particle outlet 23.

On the other hand, the gas entrained by the fine particles classified in the classification section 11 enters the volute casing 18 while maintaining a smooth flow through the current plate 31, and is discharged from the discharge pipe 36, and the fine particles are separated and captured by a bag filter or the like.

Further, the boundary particle size of the classification can be adjusted by the above-described operation by adjusting the opening area of the intake port 25 of the intake path 24 using the intake port area adjustment member 30.

Note that the first impeller 14 and the second impeller 26
As long as it rotates at approximately the same speed as the rotating container 2, it is not necessary to use the shaft 5. For example, the main plate 15 of the first impeller 14 or the main plate 27 of the second impeller 16 can be used independently. It is also possible to provide other shafts and drives.

In addition to the embodiments described above, it is also possible to apply the embodiments to a rigid type in which the embodiment is turned upside down, or a horizontal type in which the embodiment is turned upside down.

〔Effect of the invention〕

According to the present invention, since the classification action is performed in a stable classification region, it is possible to provide a highly reliable wind classifier that can perform highly accurate classification, and it is possible to achieve remarkable practical effects. .

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, and FIG. 2 is a cross-sectional plan view taken along the line shown in FIG. 1. DESCRIPTION OF SYMBOLS 1...Casing, 2...Rotating container, 3...Legs, 4...Base, 5...Shaft, 6...Bearing part, 7
... Drive wheel, 8 ... Suction path, 9 ... Discharge path, 10
... Discharge channel, 11 ... Classifying section, 12 ... Volute casing, 13 ... Vertical pipe, 14 ... First impeller, 15 ... Main plate, 16 ... Vane, 17 ...
Side plate, 18... Volute casing, 19...
Discharge port, 20...slit, 21...scattering prevention plate, 22...coarse particle collection groove, 23...coarse particle outlet, 24...intake path, 25...intake port, 26...
Second impeller, 27...Main plate, 28...Blade, 2
9...Side plate, 30...Intake port area adjustment member, 31
……rectifier.

Claims (1)

[Scope of Claims] 1. A wind classifier that introduces a solid-gas mixed fluid into a rotating container and classifies coarse particles and fine particles by centrifugal force, the rotating container having a solid-gas mixed fluid suction path, a coarse particle discharge path, and a fine particle an annular classification section is formed inside the peripheral wall of the rotating container, and an impeller rotating at approximately the same speed as the rotating container is provided in the solid-gas mixed fluid suction path. The car inlet is provided as a suction path, the blade outlet end is provided facing the classification section, the discharge path is provided in communication with the inner peripheral edge portion of the classification section, and the coarse particle discharge path is provided as a suction path of the classification section. A wind classifier characterized in that the wind classifier is provided in communication with the outer peripheral edge portion of the classification section through discharge ports provided intermittently on the wall of the rotating container at the peripheral edge. 2. In a wind classifier that introduces a solid-gas mixed fluid into a rotating container and classifies coarse particles and fine particles by centrifugal force, the rotating container has a solid-gas mixed fluid suction passage, a coarse particle discharge passage, and a discharge of gas accompanied by fine particles. an annular classification section is formed inside the peripheral wall of the rotating container, and a first impeller that rotates at approximately the same speed as the rotating container has an impeller inlet in the solid-gas mixed fluid suction channel. The suction path is provided with a blade outlet end facing the classification section, the discharge path is provided in communication with an inner peripheral edge portion in the classification section, and the coarse particle discharge path is configured to prevent rotation of the peripheral edge of the classification section. An air intake passage is provided in an annular manner around the outer periphery of the rotary container and communicates with the outer periphery of the classification section through discharge ports provided intermittently on the container wall, and an air intake passage is provided in communication with the coarse particle discharge passage, A wind classifier characterized in that the passage includes a second impeller that rotates at substantially the same speed as the rotating container, and the intake passage includes an intake port area adjustment member. 3. The wind classifier according to claim 2, wherein the first and second impellers are formed by providing blades on both sides of a common main plate.