JPH0119948B2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field There are two methods for processing powder and granules: dry method and wet method.For raw materials with a moisture content of 2% or less, dry method,
Anything larger than that is generally processed using a wet method. The present invention relates to a dry classification device.

BACKGROUND TECHNOLOGY A wind classifier is a device that classifies particles according to their size based on the principle of classification, by applying a force in a direction different from the direction of the drag force caused by the fluid, that is, a classifying force.

Gravitational force, inertial force, and centrifugal force can be considered as classification forces, and in reality, two or more of these forces often act simultaneously.

The wind classifier is published by Industrial Technology Center Co., Ltd., Latest Powder Process Technology Collection, pages 70-72, Table
3.1 As shown in the classification table of the wind classifier,
The air separator type shown in No. 12 is often used, and this is considered the basic model, with many variations added to it.

Problems that the invention aims to solve Many conventional dry classification devices use a combination of air separators, cyclones, bag filters, etc. However, all dry classification methods are greatly affected by the moisture content of the raw material, making stable operation difficult. In order to do this, drying equipment is sometimes installed, which has many drawbacks, such as a drop in classification accuracy due to adhesion of raw materials and products inside the equipment, clogging, and solidification.

Measures to solve the problem A charging chute that receives powder and granular materials with a moisture content of 3% or less, and a classification basket that has a mesh-like cage inside the casing are rotated at high speed. A pressure-feeding pipe which faces the inner surface of the central part of the classification basket and blows air from the axial direction thereof, and a pressure-feeding pipe which is inclined with respect to the axis and which is connected to the input chute to form a front chamber and a rear chamber. It is equipped with a classifier equipped with a supply chute that communicates with it, and a take-out chute for taking out the sized products outside is installed in the lower part of the front chamber, and an air exhaust machine is installed in the lower part of the rear chamber through the take-out chute and the exhaust duct. This system is equipped with a cyclone and a dust collector that collect fine powder and dust using the suction power and take it out to the outside.

Function The flow direction is changed while passing through the input chute, and the coarse particles are repeatedly flowed down and redispersed, and the generated dust is sucked up by the suction force of the exhaust fan. The raw material that has passed through the input chute is supplied to the vicinity of the inner surface of the central portion of the classification basket, which is rotating at high speed within the housing. The raw materials put into the classification basket are classified into products and fine powder by the wind and centrifugal force generated by the rotation of the classification basket, and the products are delivered from the hopper to the outside of the machine by a conveyor. Fine particles and dust are discharged from the mesh of the classification basket by the wind force generated by the rotation of the classification basket, the centrifugal force, and the suction force of the exhaust fan, and are dried by the suction force of the exhaust fan, and then enter the cyclone and back filter. The air is collected and exhausted to the outside.

Embodiment FIGS. 1 to 4 show embodiments of the present invention. In FIG. 1, 1 is a classifier equipped with an input chute 2, 3 is a cyclone, 4 is a dust collector with a compressor, and 5 is an exhaust fan.

As shown in Fig. 2, the inside of the housing 6 of the classifier 1 is divided into a front chamber 7 for collecting products and a rear chamber 8 for collecting fine powder, dust, etc. A sorting basket 9 having the same shape as that shown in FIG. The classification basket 9 has a rotary plate 11,
It is comprised of a housing 12 having a predetermined mesh fixed around the rotating plate 11. 13 is inserted into the front chamber 7 from outside the housing 6, and is connected to the spout 1 at the tip.
3a is an air pressure pipe installed facing the rotary plate 11 of the classification basket 9 at a distance, and the air outlet 13b at the rear end of this air pressure pipe 13 is connected to a blower 14 installed outside the housing 6. There is. A partition plate 17 fixed to the case 6 is provided between the opening edge of the classification basket 9 and the inner peripheral surface of the case 6, and this partition plate 17 separates the front chamber 7 and the rear chamber 8. are separated. The housing 12 of the classification basket 9 is constructed using a wire mesh, a perforated plate, a slit plate, or the like. Further, the rotary plate 11 may have a conical shape, a convex shape, a flat plate shape, etc. in addition to the concave shape shown in the figure. The type of the housing and the shape of the rotary plate are selected depending on various conditions such as the particle size of the powder to be classified, the degree of water content, the amount of air blown, and the rotational speed of the classification basket 9.

The input chute 2 provided at the top of the housing 6 is
As shown in FIG. 3, it has a double-walled structure in which surfaces other than the rear surface are closed by an inner plate 18 and an outer plate 19, and the inner plate 18 has many small holes or slits (not shown). ] is provided. Reference numeral 20 denotes a connection port of a suction duct 21 connected to a dust collector, which reduces the pressure in a gap 22 formed by an inner plate 18 and an outer plate 19 and has a U-shaped cross section to reduce dust generated in a passage 23. It is sucked out from the hole through the gap 22 and the suction duct 21, and processed by a subsequent cyclone and dust collector. 24 is a conveyor for carrying in powder and granular materials; this conveyor 24
The end of the input chute 2 is inserted into a carry-in window 25 formed at the upper rear surface of the inner plate 18. 26
is a cover made of a large number of narrow rubber sheets hanging from the upper edge of the carry-in window 25. In addition, the inner plate 18
The upper end of the passage 23 formed by the above is closed by a top plate 27. Numerals 28, 29, and 30 are weir bodies provided alternately on the opposing inner surfaces of the inner plate 18, and the plurality of weir bodies 2
8, 29, and 30 form a zigzag-shaped passage 23. Reference numeral 31 denotes a supply chute connected to the lower part of the zigzag-shaped passage 23 of the input chute 2. This supply chute 31 is provided in the housing 6 with a downward slope, and its tip opening 31a is connected to the rotary plate 1 of the classification basket 9.
1 and is disposed close to the upper part of the spout 13a of the air pressure pipe 13.

Reference numeral 32 denotes a product take-out chute formed at the lower part of the front chamber 7 of the housing 6, and a belt conveyor 33 for taking out the product is provided at a position below this chute 32. 34 is a dust extraction chute formed at the lower part of the rear chamber 8 of the casing 6. This chute 34 and the upper part 3a of the cyclone 3 installed on the pedestal 35 are connected by a J-shaped duct 36, and A suction duct 21 communicating with the input chute 2 is connected to the end of the duct 36 on the cyclone 3 side. Above duct 3
6, a tapered branch passage 37 extending downward is formed as shown in FIG. 4, and a rotary valve 40 is provided at a lower opening 38 of the branch passage 37. This rotary valve 40 is rotatable about a pivot 43 around a rotating body 59, which has a plurality of blades 41 radially provided in a case body 30 whose cross section swells into an arc shape to define a plurality of storage chambers 42. This is the configuration provided. Reference numeral 44 denotes an air volume adjusting damper 47a, 47b rotatably mounted on the upstream side of the upper opening 45 of the branch passage 37 via a pivot 46.
are flow transformation vanes rotatably provided around pivot shafts 48a and 48b at a predetermined interval in the vertical direction along the branch passage 37;
The damper 5 is provided adjacent to the air volume adjusting damper 44 on the downstream side of the damper 5 . By rotating the air volume adjusting damper 44 and the elongated current transformation vanes 47a and 47b and adjusting their angular postures as appropriate, the suction force of the exhaust fan 5 directs the air flow through the duct 36 to the upper part of the branch passage 37. A turbulent flow is generated in the vicinity of the opening 45, and this turbulent flow causes particles with large specific gravity in the dust to branch and fall into the branch passage 37. 48 is a door for internal inspection attached to the opening 50 of the peripheral wall 49 of the branch passage 37, and 51 is a repulsion plate fixed to the inner surface of the peripheral wall 49 facing the inspection door 48.

52 is a first air exhaust duct, and 53 is a second air exhaust duct, one end of the first air exhaust duct 52 is connected and opened to the upper surface part 3b of the cyclone 3, and the other end is installed on the pedestal 54. A connection opening is made to the side surface 4a of the dust collector 4 with a compressor, and both ends of the second exhaust duct 53 are connected to the other side upper part 4b of the dust collector 4 and the exhaust fan 5, respectively. 5
5 is a rotary leaf feeder 56 consisting of a screw conveyor attached to the lower opening 4c of the dust collector 4;
57 is a belt conveyor for discharging dust installed between the cyclone 3 and the dust collector 4, and 57 is installed at an angle between a position below the lower opening 3c of the cyclone 3 and a position above the end of the belt conveyor 56 for discharging dust. The screw conveyor 58 is a screw conveyor installed at an angle between a position below the end of the rotary feeder 55 and a position above the end of the belt conveyor 56 for carrying out dust.

60 is a branch passage 37 formed in the duct 36.
This is a screw conveyor that conveys the granules collected by a rotary valve 40 provided at the lower part of the screw conveyor to a belt conveyor 33 for carrying out products.

In order to classify the powder or granular material using the classification apparatus having the above-mentioned configuration, the powder or granular material is carried into the input chute 2 by the carrying-in conveyor 24. Above input chute 2
The granular material carried into the container passes through the zigzag-shaped passage 23 and is supplied to the vicinity of the inner surface of the rotary plate 11 of the classification basket 9 via the supply chute 31. When the powder passes through the passage 23 of the input chute 2, the powder collides with the weirs 28, 29, and 30 provided in the passage 23, generating dust and the like. At this time, since the connection port 20 of the suction duct 21 communicating with the cyclone 3 is connected to the gap 22 of the input chute (2),
Dust and the like in the passage 23 are sucked into the gap 22 through the small holes in the inner plate 18, and then flow into the cyclone 3 through the suction duct 21. On the other hand, the air flowing into the air pressure feeding pipe 13 from the air outlet 13b at a predetermined flow rate by the blower 14 flows into the air pressure feeding pipe 13.
After passing through, it is ejected from the ejection port 13a. Then, the powder and granules supplied from the tip opening 31a of the supply chute 31 to the vicinity of the inner surface of the rotary plate 11 of the classification basket 9 are transferred to the classification basket 9 by the air flow jetted from the jet port 13a of the air pressure pipe 13. rotating plate 11
sprayed onto the inside surface of the The powder particles blown onto the classification basket 9 by the air flow collide with the rotary plate 11, and are dispersed within the classification basket 9 while being subjected to a dispersion drying effect by the air flow. The powder and granules dispersed in the classification basket 9 are transformed into granules as products by the centrifugal force generated by the rotation of the classification basket 9, the wind force from the air pressure pipe, and the suction force of the exhaust fan 5 acting on the rear chamber 8. Completely classified into fine powder, dust and residual moisture.
The classified products are guided to the inclined inner surface of the rotating classification basket 9 by the centrifugal force, enter the front chamber 7 from the classification basket 9, and enter the product extraction chute 32 below.
From there, it is discharged onto the discharge belt conveyor 33 and carried out to an appropriate location. On the other hand, dust and the like separated from the product enter the rear chamber 8 through the mesh of the classification basket 9 due to the centrifugal force and wind force of the classification basket 9 and the suction force of the exhaust fan 5 acting on the rear chamber 8 of the housing 6 . Dust etc. that have entered the back chamber 8 of the casing 6 are sucked together with air by the suction force of the exhaust fan 5 acting on the back chamber 8 from the dust extraction chute 34 through the duct 36 to the cyclone 3, where they are centrifuged. are collected at the lower part of the cyclone 3 and collected onto the screw conveyor 57 through the lower opening 3c. The duct 36 through which the dust and the like pass is formed with a branch passage 37 provided with an air volume adjustment damper 44 and current transformation vanes 47a, 47b. Adjust as appropriate,
When a turbulent flow is generated near the upper opening 45 of the branch passage 37, residual particles with a large specific gravity are classified from the dust passing through the duct 36 due to the turbulence and fall into the branch passage 37. The particles that have fallen into the branch passage 37 are removed from the lower opening 38 of the branch passage 37.
When the particles are deposited in the storage chamber 42, the rotating body 59 rotates around the axis 43, and the particles in the storage chamber 42 are carried out from the rotary valve 40. and collected on the screw conveyor 60. The recovered granules are sent by a screw conveyor 60 to a belt conveyor 33 for carrying out the product. The air centrifuged and discharged by the cyclone 3 is
The air is sent to the dust collector 4 through the second exhaust duct 52, where fine dust remaining in the air is further separated, and the air is sent to the exhaust fan 5 through the second exhaust duct 53, where it is separated. The remaining dust, etc., is transferred from the lower opening 4c of the dust collector 4 to the rotary feeder 55.
After being collected at the top, the screws fall onto the screw conveyor 58 and are carried out.

The dust discharged from the cyclone 3 onto the screw conveyor 57 and the dust discharged from the dust collector 4 onto the screw conveyor 58 are transported by the screw conveyors 57 and 58 to a belt conveyor for carrying out dust. 56 and then transported to the appropriate location.

Effects of the Invention According to the present invention, the raw material charged into the classification basket is
The product and fine particles are classified by the wind and centrifugal force generated by the rotation of the classification basket and the suction of the exhaust fan acting on the back chamber of the classification basket, making it possible to classify large amounts of powder and granules in a short time. This makes it possible to significantly improve classification processing capacity and work efficiency. In addition, the powder input chute is shaped like a zigzag pattern to rapidly change the flow direction, and the coarse particles are repeatedly flowed down and redispersed. It is possible to efficiently classify particles. Furthermore, a branch passage is provided in the middle of the duct connecting the take-out chute at the lower part of the rear chamber of the casing and the cyclone, and an air volume adjustment damper and a current transformation vane are provided at the opening of the branch passage.
Since a turbulent flow is generated near the opening of the branch passage, this turbulent flow can classify residual particles with a large specific gravity from the dust passing through the duct, and the classification processing capacity is extremely high. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the classifier according to the present invention, Fig. 2 is a longitudinal cross-sectional side view of the classifier, Fig. 3 is a schematic perspective explanatory diagram of the input chute, and Fig. 4 is the classifier and cyclone. FIG. 2...Input chute, 3...Cyclone, 4...Dust collector, 5...Exhaust fan, 6...Casing, 7...Front chamber, 8...Back chamber, 9...Classifying basket, 13...Air pressure pipe, 13
a... Spout port, 23... Passage, 32, 34... Takeout chute, 36... Duct.

Claims (1)

[Scope of Claims] 1. A front chamber and a back chamber are provided by supporting an input chute for receiving powder and granular material having a moisture content of 3% or less and a classification basket having a mesh-like housing inside the housing so as to rotate at high speed. A classifier is provided with an air pressure pipe which is formed into a compartment, faces the inner surface of the central part of the classification basket and blows air from the axial direction thereof, and a supply chute which is inclined with respect to the axis and communicates with the input chute, At the bottom of the front chamber, there is a take-out chute for taking out the sized product to the outside, and at the bottom of the back room, the fine powder and dust are collected by the suction force of the exhaust fan through the take-out chute and the exhaust duct. 1. A dry classification device for powder and granular materials, characterized in that a cyclone and a dust collector are installed in series. 2. The input chute is made up of an inner plate and an outer plate, forming a closed double-walled gap between the inner plate and the outer plate, and connecting the gap to the dust collector via a duct. In addition, a large number of small holes are bored in the inner plate, and the passage formed by the inner plate is formed into a zigzag passage by a weir body provided on the inner surface. Dry classification equipment for powder and granular materials. 3 A branch passage extending downward is provided in the middle of the duct that connects the take-out chute at the bottom of the rear chamber of the housing and the cyclone, and an air volume adjustment damper and an elongated current transformation vane can be rotated at the opening of this branch passage. 2. The dry classification apparatus for powder and granular materials according to claim 1, further comprising a rotary valve provided at the lower opening of the branch passage and having a storage chamber.