JPH0268182A - Gravitational sorter of powder - Google Patents

Abstract

PURPOSE: To prevent the degradation in sorting quality by providing the bottom of a housing with a hollow housing having an inclined bottom having perforations and a threshold across the direction where material flows. CONSTITUTION: Molding sand which is the raw material is supplied onto the uppermost end 3 at the bottom 4 with the perforations of the housing 1 by a belt conveyor 25. The air streams ascending through the perforations 7 at the bottom 4 pull up sand grains into continuous axial passages 13 together with the fluidization head of the sand created on the surface of the bottom 4 by the suction force generated in the housing 1 by the centrifugal fan 7, by which the sand grains are begun to be separated to the coarse sand and the fine sand. The air steams send the fine particles through a pipe 11 into a cyclone 21 and collect the particles into a vessel 23. These particles are carried out by the belt conveyor 24. As a result, the high treatment quality may be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to fluidic separators for various powders in an upward flow of air, and more particularly to gravity separators or separators.

The present invention is suitable for use in metallurgy, foundry, mining, chemical and other industries that require the handling of powders, depending on their particle size, specifically in the range of Fio, 5-5R. /Used to separate or sort products into two or more products with roughness.

Conventional Technology Providing equipment that can separate or sort powders with high efficiency is due to the remarkable technological advances made in powder metallurgy and its metallurgy, which precedes casting and molding. This has become very prominent today as strict requirements have been placed on the particle size of semi-finished products and finished products. Fluid sorting is one of the most promising sorting technologies today.

In the application of the principle of fluid sorting of powders, a cascade gravity separator or sorter consists of cavities divided by successive vertical partitions in a series of channels written above an inclined and perforated bottom. The vessel had the preferred KF7r numerical configuration.

In the axial channel, the sorting of the material is carried out by a separation element (SU, A, 7871) 3 mounted on the inner wall of the channel.
) or the zigzag-shaped walls of the alley itself (GB, B,
2623038).

In such a configuration of the sorter, Nibblemeyer coefficient 2 =
The efficiency expressed as dts / d2s ・100% is 70 to 75% (where (its and d2. are
The fluid density of the initial powder μ = 2-2.5 m
g/m' and a processing power of 6O-100t/hour. The power input usually does not exceed 2.5 kW per tonne of raw material.

In the above-mentioned sorter, the separation process of powder raw materials is carried out by constructing a fluidized bed in the airflow rising through the perforated bottom. The sludge moves downward under gravity, aided by fluid resistance, and separates the material from finer to coarser particles. The finer particles are carried by the updraft in the separation shaft with concomitant separation and release of particles of intermediate coarseness and weight. In this way, in the configuration described above, the separation of coarser particles and finer particles is repeated and the efficiency and speed described above are maintained. However, with the type of sorter or separator described above, the requirements regarding the particle size of the separated powder product are particularly demanding, for example in the production of foundry sand, abrasive powders and abrasives, raw materials for powder metallurgy.
This has been found to be insufficient because the density of the workpiece differs in the longitudinal direction of the bottom of the perforation and along its narrow path, impeding the ingress of the material and resulting in finer products. It is said that most of the pigeons are returned on the upstream narrow path, while the downstream narrow path remains underloaded. However, on the other hand, the reduction in density of the material to be separated leads to more coarse particles being carried away inappropriately and to the growth of the gas separation barrier, so that the individual channels separate the raw materials into individual ant barriers. However, it is also known that the resultant separation of the finer and coarser products becomes even finer and coarser particles, respectively. In the above and in the following description, the term gas separation barrier I is used to describe the average outer diameter of the particles that are converted with equal probability into finer and coarser separated products in the actual separator or sorter. It will be done. Therefore, the density non-uniformity and the perforated @:8IS and the length of the separation axis are
Affects the quality of sorting. Furthermore, in the one-throw configuration sorter described above, the density of the material tends to be non-uniform across the width of the perforated bottom, and slight errors in manufacturing or installation of the perforated bottom can result in uneven material density. When inserting raw material that is uneven in the width direction of the bottom,
Significant. In both cases, the raw material flows along one side of the bottom, closer to the sidewalls, towards a higher density flow;
The density at the bottom of the sorter at the side wall of the pond will be reduced. Correspondingly, the finer particles carried in the denser stream of material will be returned in large quantities towards the coarser ones, contaminating the coarser product and consequentially having a negative impact on the sorting quality. .

In other words, non-uniform density of the material to be separated across the length and width of the bottom and separation axis will reduce the sorting quality. It is further stated that the sorting efficiency increases as the residence time of the powder in the sorter increases, since the powder is highly susceptible to the separation action of the air flow. , reducing the probability that coarser products will be contaminated by finer particles. In that case, the residence time of the particles in a sorter or separator of the type described above largely depends on the angle of inclination of the perforated bottom; the less the inclination of the bottom, the longer the residence time of the particles in the sorter. However, in most of the examples,
The angle of inclination of the bottom with respect to the water surface cannot be less than 9°. This is because most of the powder that is actually handled has a wide range of particle sizes, and during the operation of the sorter, the largest particles do not turn into a fluid and tend to stay at the bottom, blocking the perforations. The advance of the powder along the bottom towards the means for drawing off the coarser product results only in it falling down the sloped bottom. In this way, the angle of inclination, and therefore the residence time, is limited in separators or sorters of the type described above, further impairing the quality of the sorting. In summary, with the above configuration of the separator, the sorting quality is affected by the non-uniformity of the density of the material to be separated in the longitudinal and width directions of the perforated bottom and by the limited residence time of the powder in the separator. , being adversely affected.

There is.

Attempts to extend the residence time of the powder in the sorter have also been made in the known gravity sorter of Ike (S
U, to 4F+68141° This sorter has a housing divided by vertical partitions in a narrow passage. Each vertical axis is further divided by partitions into channels, the walls of which support mutually juxtaposed sorting members. The housing has a stepped, sloped, perforated bottom, the slope of this bottom being similar to the housing of the sorter from the insertion means for the raw material supply mounted on the housing of the sorter. towards a means of ejection of coarser sorted products mounted on. The insertion means are provided above the upper end of the bottom and the coarse product ejecting means are provided adjacent to the bottom of the bottom. Air and finer sorted product extraction pipes are mounted at the top of the housing. A gap is provided between the lowest end of the vertical bulkhead and the perforated bottom, sufficient for the passage of powder. Each septum of the channel is a gate pivoted at the lowest end of the septum bone, facing each step of the bottom. Each gate serves to reduce the flow rate of air containing finer particles of feedstock from one channel to the next. Moreover, it also helps to slow down the progress of the material along the bottom, increasing the residence time in the sorter and improving the sorting quality to some extent.

However, the sorting configuration described above is sufficient to overcome both the non-uniformity of the material in the longitudinal and width directions of the perforated bottom and the insufficient residence time of the powder in the sorter! /cFi, so the performance of the powder sorter could not be improved in any way.

In operation of the separator, powder is fed to the upper end of the perforated bottom by insertion means in the separator housing. A fluidized bed of material is formed on the perforated bottom by the air flow rising through the bar 7 olefin. This fluidization follows the progression of the material in the longitudinal direction of the sloped bottom towards the coarser product removal means. During this process, the powder is sorted from coarser to finer fractions, the latter being carried away by the air stream in the separating shaft, which is placed in order to cause the separating element to repeat the separating action. The separation process flow sheet of this sorter results in non-uniform longitudinal and widthwise material density throughout the perforated bottom and separation channels in several passes. As a result, in the selection of potassium chloride in powder manufacturing technology, most of the raw material returns to the upward flow path. For example, when the total yield of fine products γ is 35.7%, the distribution over the entire narrow path is T 1f = 24.34%, r 2f = 7.08%
.

γ,,=4.28%. As can be seen from the above data, the convergence of the first axis is almost 6 @ that of the third axis.
, and the density of the flow in the longitudinal direction at the bottom is also
This is a difference of about 6 times. As mentioned in Akatsuki, the decrease in the density of the material in successive narrow passages is caused by the decrease in density from narrow passage to narrow passage.
Separation barrier completely occurs. All of these reduce the operating efficiency of the sorter and also have an adverse effect on #'i sorting quality. Furthermore, as already mentioned, errors in the manufacturing or mounting of the base and uneven material insertion across the width of the initial perforated base can result in material advancement that is dense on one sidewall. give rise to layers;
A thin layer #it may occur on the other sidewall. As a result, fine particles enter the denser layers and are carried along with the coarser product, contaminating the latter and reducing the sorting quality.

It can be seen from the operating experience of the sorter described above that the angle of inclination of the perforated bottom with respect to the water flow surface is the same as that of the bar 7 at the bottom because the size of the particles contained in most powders varies widely. The angle cannot be set below 9° for fear that the opening will be blocked by the coarsest particles and fluidization will be hindered, and the slope of the perforated bottom will only move along the slope. This limitation of the perforated bottom angle of inclination also limits the residence time of the material being separated within the sorter, which adversely affects the performance of the sorter.

Problems to be Solved It is an object of the present invention to solve the problems in the gravity separator for powders, in which the configuration of the perforated bottom in the separator is such that the bottom part and the axis of the separator extend over the separation axis. To improve the quality of powder sorting by quickly making the density of materials separated in the direction and width direction uniform and by extending the residence time of the materials in one sorter. .

Precautionary Means to Solve the Problem The purpose is to provide a hollow housing with an inclined bottom having a par 7 olefin chamber for gas to pass through, separation members housed above and below in the housing, and a raw material. means placed on the trowel top end of the bottom of the perforation tube for insertion into said separator and the lowest end Kf of the bottom of said perforation tube for removing the separated coarse material;
and at least one pipe mounted on the top of the housing for exposing said gas and fine materials, in the present invention, the perforated bottom of said housing is adapted to contain the material. In the improved configuration of the mouth sorter or separator disclosed herein, which is achieved, it comprises at least one threshold provided at the bottom of said nozzle transverse to the direction of flow. Due to the provision of at least one threshold in the perforated bottom, the material is restrained by the upward flow of this threshold, so that even in a fluidized bed with a perforated bottom, there is no space or space in the nozzling. Also in the separation axis above the threshold, the density of the material in the rising region of the threshold increases stepwise. The angle at which this density is increased stepwise is determined by selecting the height of this threshold.Thus, by setting one or more thresholds, it is possible to improve the quality of the separation or sorting of the powder. , the density of the material can be adjusted within the space of each separation axis and in the longitudinal direction of the perforated bottom to make the density uniform. Still further, the arrangement of the or more thresholds slows the progress of the material along the sloping perforated bottom towards the means for ejecting the coarser product and prolongs the residence time of the material within the sorter. Further improving the quality of separation or sorting, the threshold is basically plate-shaped, with alternating peaks and valleys at its upper end, and the lowest end of each family reaching a perforated bottom. It is even more advantageous.

Due to this configuration of the threshold, the coarse particles of the H family are not fluidized and are directed through the valley of the threshold to the means for ejecting the coarse product by rolling on the perforated bottom. Since the par 7 can proceed without any obstacles, it is avoided that the par 7 groove with one hole is blocked ◎ There are two or more thresholds at the bottom of the perforation, and each successive threshold is one that precedes the other. It is further advantageous if the valley of the threshold and the peak of the next one are arranged facing each other.

When the thresholds are arranged sequentially in this manner, the peaks may be due to manufacturing errors in the perforated bottom, mounting errors, or input into the sorter across the width of the perforated negative bottom. Uneven insertion will result in the formation of a dense layer of powder. This helps to equalize the density of the powder across the width of the bottom, preventing fine particles in the dense layer of powder from entering the coarser product being dispensed, thereby improving sorting quality. let

If the conditions for the purity of the sorted product are the same, of two sorters with different efficiencies, the one with the higher efficiency will
It is known to operate at higher flow densities of the material to be separated. Furthermore, the sorting machine is 1M! Ql (
kg/s) is expressed by the following formula: Q+ =μ・Q2 Here, μ is the flow density of raw material powder: kg/, l3Q
2 is the flow rate of air passing through the sorter: m'/'' As can be seen from the above equation, the throughput of the sorter increases in direct proportion to the powder flow density. For example, in a separator that does not require high purity of the sorted product, such as in the production of building materials or fertilizers, the separator made according to the present invention is fully capable of increasing the throughput by increasing the flow density of the raw material. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A gravity sorter according to the invention, for example for sorting foundry sand according to its particle size, comprises a housing 1. Disposed on the upper end 3 (FIG. 2) of the perforated bottom 4 is a feeding means in the form of a chute 2 for inserting the raw material, the sorted and coarse product V! jI and a downwardly directed discharge pipe 5 mounted on the lowest end 6 of the perforated bottom 4.

As the name suggests, the perforated bottom 4 has perforations 7 (
(Fig. 3), and furthermore inclined with respect to the water plane in the direction of progress of the material to be sorted, for example towards the means for peeking out the coarse product being sorted from the supply means. ing. This perforated bottom 4 has a continuous threaded eye 8 (FIG. 2) mounted on its surface, which is plate-shaped and whose upper edge alternates with ridges 9.
(Fig. 3) and forms a valley 10. Multiple pipes 1)
(Fig. 1) is mounted on the upper end of the housing to draw out the air that discharges the sorted fine products. 1 sorter housing, 12 vertical bulkheads (Figure 2)
The continuous separating shafts 13 are arranged alternately in each separating shaft 13 and house separating elements consisting of oblique shelf projections 14. The shelves 14 are mounted alternately on the vertical bulkhead 12 and on the side walls 15 and 16 (FIG. 3) of the housing (FIG. 2). Next to creating an upward airflow through the bottom 4 with a par 7 orifice, the sorter has a centrifugal fan 17 (FIG. 1) whose suction pipe 18 is connected via an air duct 19 to a manifold 20. It is connected to the. Each pipe 1) for drawing air containing fine products from the conveying air
The screened fine products are passed to a cyclone separator of suitable construction known for separating them. Exhaust pipe 221:t of each cyclone 21, connected to manifold 20IC,
Each container 23 of each cyclone 21 is separated and conveyed by a belt conveyor 2 of a known suitable construction for carrying out ultra-fine products.
4 placed on top. Another belt conveyor 25 is provided for supplying raw sand to the chute 2. A further belt conveyor 26 for discharging the sorted coarser products is placed 1c below a feed opening 27 of known and suitable construction which connects to the take-off pipe 5.

motion This gravity sorter operates as follows.

The raw material foundry sand is passed through the shade 2 onto the belt conveyor 25 (see Fig. 1, the uppermost end 3 of the bottom 4 with bar 7 oration of the housing 1 of the sorter (Fig. 2) and in the direction of the arrow %a1. Supplied.

The suction force generated in the housing 1 by the centrifugal fan 17 (FIG. 1) causes the bar 7 in the bottom 4 to
The airflow rising through the sloping par-7 oreshi (FIG. 2) pulls the sand grains into the continuous axial passage 13 with the fluidized bed of sand created on the surface of the sloping par-7 oreshed bottom 4, causing gravity to The fluid resistance of the particles begins to separate the sand into coarse and fine particles.

The fine particles are subject to the repeated movement of the continuous separating ledge 14, which releases the upward flow from the coarse particles that have been incidentally contained within the air flow. carried by the current. The air stream sends the fine particles into a cyclone 21 via a pipe 1) (Fig. 1), collects the particles separated from the air in a container 23, and then conveys them by a belt conveyor 24 in the direction of the arrow. carry it out to The friendly air that removes fine particles is passed through the exhaust pipe 2 of each cyclone.
2, passes through the manifold 20 and the air duct 19, and enters the suction pipe 18 of the centrifugal fan 17. Bottom 4 with sloping par 7 oreshicon on fluidized bed (
Fig. 2)'f, the descending coarse particles release the fine particles, descend from the sorter via the pipe 5 (Fig. 1) and the supply port 27, and are moved by the belt conveyor 26 by the arrow -Q/'
It is carried out in the direction.

As the raw foundry sand advances along the sloped bottom 4 (FIG. 2), the sand is restrained before each successive threshold 8, so that in each area of these thresholds 8, the sand is Both in the fluidizing bed of the housing 1 and in the space of each separating shaft 13 above the threshold 8, an increase in the density of the material, for example foundry sand, takes place. This increase in density is caused by each successive height of the threshold 8, making the density of the foundry sand uniform over the entire separation axis 13 and along the length of the bottom 4 with par 7 orifice, thereby improving the quality of the screening. improve. Furthermore, the threshold 8 is such that the sand is at the bottom 4.
The progress of the sand toward the peeking pipe 5 along 1C is delayed, the residence time of the sand in the sorter is extended, and the sorting quality is further improved. Each successive threshold 8
is the valley 10e facing the peak 9 of the preceding threshold 8
(furthermore, the first threshold 8 closest to the feed inlet also has a similar valley 10), so that the coarsest part of the raw sand that is not fluidized is the bottom 4t with the inclined perforation. Since it rolls without obstruction towards the -9 exit pipe 5 (FIG. 2), blockage of the bottom 4 with the par 7 oreshicon is avoided. The denser 1)4-t of the raw sand passes through the inclined bar 7 oration 7 close to one of the side walls 15 or 16 (Fig. 3) of the housing 1 of the sorter, so that each threshold 8 (Fig. 2) The pile at the top breaks up this dense layer of sand, thereby also equalizing the density of the powder across the width of the bottom 4. Due to the ridges 10 (Fig. 3) facing each family of the preceding thresholds 8 (Fig. 2), such equalization of the density of the material to be separated is distributed in the longitudinal direction of the base 4, e.g. The sorting machine or separator constructed according to the present invention prevents the fine particles in the dense f@ of the raw material from being carried into the coarse product, further improving the sorting quality. By increasing the flow density, it can be operated efficiently and thus a high throughput can be obtained ◎ Effects of the Invention A nine-gravity sorter constructed according to this invention for sorting foundry sand has the following features: The results were shown: Raw material flow density μ = 3
．． 5kg Otsu-1 processing amount Q1 = 20t/hour.

External size 1600+s (height) x 400mm (@)Xt
At 900 m (length), the separation efficiency is approximately 80% based on the Niblmeyer coefficient. The required human power, including dust removal from the air, is less than 1.5 kW per ton of powder separated.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the overall outline of a gravity sorter for separating powder, constructed according to the present invention; FIG. 2 is a ++-n view of the sorter shown in FIG. 1; In the line cross section,
FIG. 3 is a schematic cross-sectional view showing the progress of the material in the longitudinal direction, and FIG. 3 is an enlarged cross-sectional view taken along the line II in FIG. 2. In the drawings: 1: Housing 2: Chute 3: Top end of bottom
4: Bottom 5: @ Extruding pipe 6:! Bottom end of section E
7: Par 7 oleasisine for upward airflow 8: Threshold 9: Peak 10: Valley 1): Air and fine particle extraction pipe 12: Vertical bulkhead 13: Separation axis 1
4: Oblique shelf projection 15.16: Side wall 17: Centrifugal fan 18: Suction pipe 19: Air duct 2o: Manifold 21: Cyclone 22: Exhaust pipe 23:
Container 24.25.26: Belt conveyor 27: Supply port

Claims (1)

Claims: 1) a hollow housing (1) with an inclined bottom (4) having perforations (7) for the passage of gas;
separating members housed one above the other in said housing (1), means placed on the uppermost end (3) of the perforation bottom (4) for inserting the raw material into said sorter; means placed at the lowest end (6) of said perforated bottom (4) for extracting material and at least one pipe mounted on the top of the housing (1) for extracting said gas and fine material; and at least one threshold (8
) across the direction of material flow to the housing (1).
A gravity sorting machine for powder, characterized in that it is provided at the bottom (4) of a powder. 2) In the gravity sorting machine according to claim 1,
The threshold (8) is basically plate-shaped, and its upper end forms alternating peaks (9) and valleys (10), and each valley (10)
A gravity sorting machine, characterized in that the lowest end of the machine reaches a perforated bottom (4). 3) A gravity sorter according to claim 1 or 2, in which the perforated bottom (4) has two or more thresholds (8), each successive threshold (8) being different from the preceding threshold. (8) Valley (
10) and the next pile (9) are arranged so as to face each other.