JPS6130832B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a centrifugal sieve that sieves particles using the centrifugal force of a rotor.

(Prior Art) The purpose of such a centrifugal sieve, already known from DT-OS 1607631, is to separate particles of different size, shape and specific gravity into coarse particles (above a certain critical diameter). and fine particles (those below a critical size). The particles to be sorted are introduced from above into the sorting chamber (the annular space between the guide plate ring and the sorting rotor), and at the same time, sorting air flows into the sorting chamber from the outside through the guide blade ring. The sorted air performs a swirling motion, and as it does so, transports the particles onto appropriate paths of movement. In the sorting chamber, the particles are subjected to two opposing radial forces. This is the air resistance or suction force created by that one inward air flow, and particles tend to be drawn inward by this air resistance. The other is the centrifugal force caused by the swirling motion of the air, and the particles tend to move outward due to this centrifugal force. and for a given radial and axial air velocity there is one critical particle size,
At this size, these two forces are the same.

In this case, coarse grains larger than the critical size move radially outward due to the centrifugal force being greater than the drag force, and reach the coarse grain outlet at the lower end of the sorting chamber earlier or later. On the other hand, fine particles smaller than the critical size are transported radially inward by the sorting air because the resistance force is greater than the centrifugal force, and this air passes through the grooves of the sorting vanes and moves inward. inflow,
It is sucked into a fine particle sorting air outlet which connects in the axial direction to the inner space of the sorting vane. After this, the fine particles are separated from the sorted air, whereupon the sorted air is again introduced into the sorted air inlet and can be circulated again. Such a sorter is primarily intended to produce fine particles of the smallest possible size with a narrow size distribution, and is aimed at particles with a limit of 2 to 4 .mu.m. Such very fine particles are often needed as fillers in plastics, automobile tires, pigments and paints, or as coatings for paper. The coarse particles are used for other purposes or are further crushed into fine particles.

For economical work, it is very important that the fine particles contained in the produced granules are sorted out as much as possible by passing them through a sorter, so that the production efficiency is relatively high. It is.

(Problem to be Solved by the Invention) However, conventional sorters have a problem in that the fine grain yield (the ratio of the fine grains taken out or obtained to the fine grains contained in the produced mixture) is generally low. It was hot.

In addition, since the flow rate of conventional sorters is high, fine particles are strongly hit against the wall surface and adhere to the wall surface. This is especially true in the case of the first fine-grained layer. As a result, subsequent flow conditions deteriorate, resulting in reduced production efficiency.

In particular, such layered deposits (so-called "egg shells") sometimes burst and mix into the granules, making them unusable or causing severe damage. Difficulties may arise. In order to avoid the occurrence of such deposits, the flow rate is limited, but in this case, the production capacity is also limited.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a centrifugal sieve of this type which has a large yield of fine particles and which is adjustable.

According to the invention, this object is achieved by making the entire centrifugal sieve machine rotatable around one horizontal axis. In other words, the entire centrifugal sieve can be tilted at an appropriate angle, and depending on the degree of inclination, the residence time of the mixed particles in the sorting chamber can be adjusted in accordance with the particle size, density, and other influencing sizes. I can do it. When the residence time is long, the acquisition ratio of fine and small particles contained in the granules increases. Furthermore, particularly coarse particles fall under gravity onto the inclined sorting rotor, are thrown out by the rotor, and impinge on guide vanes. As a result, in addition to a comminution effect, decomposition takes place. That is, the fine particles adhering to the coarse particles are separated from the coarse particles, and the smallest particles are drawn out by the sorting rotor and are not "lost" along with the coarse particles.

Both ends of the sorting rotor are wrapped by exclusion rings. This exclusion ring performs a rectifying action and improves selection performance. Furthermore, in order to make the centrifugal sieve machine versatile, the guide vanes are individually displaceable in the radial direction. The ends of the guide vanes are oriented radially in the container lid, and this direction is adjustable. In this way, the radial depth of the sorting chamber can be optimally adjusted and the separation area can be brought fairly close to the outer diameter of the sorting rotor. This ensures that all the fine particles reach the vicinity of the rotor and are drawn inward by the screened air. If the separation region is too far away from the sorting rotor, there is a risk that the fine and small particles will reach the coarse particle outlet together with the coarse particles. This makes it possible for the width of the sorting chamber, ie its radial length, to be matched optimally to the set inclination and thus to the residence time.

The centrifugal sieve according to the present invention has only one granule and screening air outlet, and one granule and screening air outlet are connected to each end of the screening rotor. Therefore, in addition to increasing the yield of fine particles,
Production capacity will be increased.

Because there are fine particles and sorted air outlets at both ends,
The cross-sectional area of the outlet is approximately doubled, and therefore, although the production capacity is high, the flow velocity is low and the adhesion of fine particles to the wall surface can be reduced.

Further, according to the invention, adhesion of fine particles to the wall surface is prevented by enclosing both fine particle separation air outlets in each case in one cooling chamber in the vicinity of the rotor. Cooled particles are less likely to adhere to cooled surfaces. In this case, it is advantageous that the bearings of the rotor for sorting, which are pivotally connected at both ends, are each located within the cooling chamber. As a result, the bearings are cooled at the same time, which is advantageous both for operational safety and for increasing the service life of the machine.

Furthermore, each end of the sorting rotor is provided with a labyrinth packing, which is connected to one of the cooling chambers through a groove. This prevents coarse particles from reaching the sorting air fine particle outlet from the sorting chamber.

(Example) For a more detailed explanation, one example will be described below with reference to the drawings.

FIG. 1 shows a longitudinal section of a centrifugal sieve according to the invention.

Figure 2 shows the centrifugal sieve machine viewed from above, with a cross section shown on the left and a plane view on the right.

FIG. 3 shows a portion of FIG. 1, namely the labyrinth and packing, through which air from the cooling chamber is circulated.

This centrifugal sieve machine has one concentric, substantially cylindrical container 1 with one tangential air inlet 2 for sorting. Air enters and flows evenly across the entire shaft height.

A ring 9 of inclined guide vanes is provided within the container and radially spaced from its jacket. Also, radially spaced apart from the ring 9 of the inclined guide vanes, there is a ring 11 of the plate of the rotor 10 for sorting.
is provided. The particles to be sorted are introduced from above into the sorting chamber 23 between the ring 9 of the inclined guide vanes and the ring 11 of the rotor plate. An annular groove 22 for feeding the granules is provided in the upper wall of the container, and one connecting pipe 7 opens into this annular groove 22. Connection pipe 7
The other end extends to the outside of the container 1, from which the mixed particles are fed as shown by the arrow 21. On the opposite side of the container, ie on the lower side, a funnel-shaped coarse particle outlet 8 is provided.

At both ends of the sorting rotor, fine particle sorting air outlets 3 and 4 are provided in the form of a single curved tube, the diameter of which approximately matches the inner diameter of the rotor. According to the invention, the entire centrifugal sieve machine is rotatable around one horizontal axis. In this embodiment, the horizontal shaft 30 is connected to the sorting rotor 1.
It is perpendicular to 0. This horizontal axis 30
can be attached by known methods, such as by supporting the outer wall of the container 1 with bearings.
This allows the entire centrifugal sieve to be tilted in an appropriate manner. In addition, fine and small particle sorting outlet 3,
4, the connecting pipe 7, etc., and peripheral devices may be connected using flexible pipes, for example, hoses, thereby effectively maintaining communication with the peripheral devices when in the tilted state.

The fine-grain sorting air outlets 3, 4 are each surrounded by a cooling air chamber 17, 18, each of which is supplied with cooling air through a connection indicated by an arrow 19, thereby , which prevents fine particles from adhering to the outlet. Cooling air chamber 1
7, 18, both ends of the shaft of the rotor 10 passing through the curved outlet are also connected to the bearing consols 5, 6.
It is attached to the shaft. The bearing is therefore also cooled. Since there is an overpressure in the cooling air chambers 17, 18, fine particles cannot penetrate therein (see arrow in the shaft). The drive is performed by connecting a pulley 12 attached to the shaft end of the rotor 10 to the output shaft of a motor (not shown) fixedly attached to the upper end of the container 1 via a V-belt. Note that this power transmission mechanism may use, for example, a gear mechanism instead of the pulleys and V-belts.

Both ends 13 and 14 of the sorting rotor 10 are open and in close contact with the fine and small particle sorting air outlets 3 and 4. Packing 15, 16 is provided between the sorting rotor and the container, and this packing is a flat disk or a labyrinth. Air circulates from the cooling air chambers 17, 18 through the cleaning air groove 27, blocking the space between the sorting chamber 23 and the fine particle sorting air outlets 3, 4 (arrow 19 in FIG. 3).

A support disk 24 having a radial through hole is shrink-fitted onto the axis of the sorting rotor 10. Exclusion rings 25, 26 are placed on the outer periphery of the rotor end.
is applied.

With this configuration, particles to be sorted are introduced into the upper part of the sorting chamber 23 via the connecting pipe 7 and the annular groove 22. At the same time, sorted air flows into the sorting chamber 23 through the ring 9 of inclined guide vanes. The sorted air that has flowed into the sorting chamber 23 performs a spiral motion,
Further, the rotating rotor 10 intensifies its spiral motion, and the particles riding on the rotor 10 generate air resistance directed radially inward and centrifugal force directed radially outward. As a result, the coarse particles larger than the limit size are overcome by centrifugal force, move outward in the radius, and move downward due to their own weight, head toward the coarse particle outlet 8, and are discharged to the outside.
On the other hand, fine particles smaller than the limit size overcome air resistance, are carried by the sorting air, are directed into the rotor 10, and are further discharged to the outside from the fine particle sorting air outlets 3 and 4.

By rotating the entire centrifugal sieve machine around the horizontal axis 30 and tilting it, mixed particles, especially coarse particles, do not fall directly to the coarse particle outlet 8, and the residence time in the sorting chamber 23 is reduced. extends. In addition, the coarse particles have an increased chance of colliding with the ring 9 of the inclined guide vane or the ring 11 of the rotor plate, and the coarse particles themselves are crushed or the fine particles attached to the coarse particles are separated.

(Effects of the Invention) As described above in detail, the present invention rotates the entire centrifugal sieve machine around a horizontal axis so that it can be tilted, so that the residence time of particles in the sorting chamber is extended and coarse particles are The chance of particles colliding with the container or rotor is increased, resulting in improved particle yield and therefore production efficiency.

In addition, since the area near the rotor for separating the fine and small particles is surrounded by a cooling chamber, cooling of the particles and the wall surface is promoted, preventing particles from adhering to the wall surface, further improving production efficiency.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a centrifugal sieve machine showing an embodiment of the present invention. 2 is a plan view showing a half section of the centrifugal sieve shown in FIG. 1; FIG. FIG. 3 is a partially enlarged sectional view showing the labyrinth packing shown in FIG. 1 in an enlarged manner. DESCRIPTION OF SYMBOLS 1... Container, 2... Sorting air inlet, 3, 4... Fine particle sorting air outlet, 5, 6... Bearing bracket, 7... Connection pipe, 8... Coarse particle outlet, 9... Ring of inclined guide vanes, 10... Rotor ( for sorting), 11... plate ring, 13... end, 14, 15, 16... packing,
17, 18... Cooling air chamber, 22... Annular groove, 23...
Sorting chamber, 24...Support disk, 25, 26...Exclusion ring, 27...Cleaning air groove, 30...Horizontal shaft.

Claims (1)

Claims: 1. A container having a generally cylindrical, tangentially oriented selected air inlet, within which the container is radially spaced apart from and centered on the container envelope. A ring of inclined guide vanes is provided integrally with the container, and inside the ring of inclined guide vanes,
One sorting rotor is provided, and an inlet for introducing particles to be sorted upward is opened in a selection chamber existing between the ring of inclined guide vanes and the sorting rotor; A coarse particle outlet is opened at the bottom, and an outlet for sorting air carrying fine and small particles is connected in the axial direction of the rotor.Furthermore, the fine and small particle sorting outlet is surrounded by a cooling air chamber near the rotor, so that the whole body is A centrifugal sieve machine characterized by being provided so as to be tiltable around one horizontal axis. 2. The centrifugal sieve machine according to claim 1, in which both ends of the rotor are each surrounded by one exclusion ring. 3. The centrifugal sieve machine according to claim 1 or 2, in which the radial distance from the sorting rotor to the inclined guide vanes of the ring of inclined guide vanes is adjustable. 4. The centrifugal sieve machine according to any one of claims 1 to 3, in which air outlets for separating fine and small particles are connected to both ends of the sorting rotor in the axial direction. 5. In the centrifugal sieve machine according to claim 1, the end of the sorting rotor is provided with a labyrinth and packing, and the labyrinth and packing are connected to the cooling air chamber through one groove. thing.