JPH08281214A - Centrifugal classifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal classifier which is made shorter in distance between each bearing of rotor axes and is able to approach from outside for maintenance, checks and repair. SOLUTION: The centrifugal classifier has an inlet 3 for classifying air extended toward a tangential direction along all height of a classifier rotor 2 in an almost cylindrical housing, and a rotor axis 14 of the centrifugal classifier extends to the outside through outlet spaces 17, 18 for fine particles- classifying air at the both ends in an axial direction, and the diameter of the outlet space is nearly equal with the diameter of a classifier rotor. Each of the outlet spaces 17, 18 has a projection part 19, or 20 extending to the inside in the axial direction, and bearings 21, 22 for the rotor axis are accommodated in the projection parts. The outlet spaces 17, 18 surrounding the bearings 21, 22 extend swirlingly or spirally towards the outside in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an inlet for classifying air that extends tangentially over the height of a classifier rotor in a generally cylindrical housing, and the rotor shaft is both shafts. A centrifugal classifier of the type which extends outwardly through the outlet for fines-classified air at the end of the direction, the diameter of which is approximately equal to the diameter of the classifier rotor.

[0002]

2. Description of the Prior Art Centrifugal classifiers of this kind are already known from DE 2951819. Such a classifier is characterized in that it has a high processing capacity and efficiently takes out fine particles, and that there are almost no coarse particles or substances larger than a prescribed size in the fine particles.

However, the known construction has the disadvantage that the shaft is relatively long and thus heavy. In other words, the two outlets for the fines-classified air are each formed by a knee-shaped pipe member whose diameter corresponds approximately to the rotor diameter. The rotor shaft is guided on both sides through this raised outlet-tube element, in which case the shaft penetration must be well sealed against the ambient air. One bearing for the shaft is provided on each side of the shaft penetration. A belt wheel or the like is attached to the upper end of the shaft.

The rotor shaft as well as the classifier rotor are generally
In order to obtain the required strength and reduce vibration,
The construction must be robust and relatively stiff corresponding to the large axial distance between the two bearings.

In the centrifugal classifier already known from DE-A 28 25 400, the rotary vanes are fixed at both ends to one end ring, respectively, and both end rings are each surrounded by their outer circumference. Bearings in hydrostatic, aerostatic, or electromagnetic bearings. However, bearings of this kind are quite expensive, especially when the diameter of the end rings is large.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to reduce the distance between the rotor shaft bearings in a centrifugal classifier of the type mentioned at the outset and to maintain,
It should be accessible from the outside for inspection and repair. In addition, the optimal conditions for obtaining fine particles that do not require further classification are the outlet chamber for classification air,
Achieved by a short bearing spacing and good access to the bearings.

[0007]

The above-mentioned problems are solved by the features described in the characterizing part of claim 1 in the independent form. That is, in the centrifugal classifier of the present invention, the outlet chamber for each of the fine particles and the classified air has a protrusion extending inward in the axial direction, and a bearing for the rotor shaft is provided in the protrusion. The outlet chamber that houses the bearing and surrounds the bearing
It is characterized in that it expands in a spiral or spiral shape outward in the axial direction.

The inwardly extending projections or ridges for accommodating the bearings occupy a relatively small space, so that the cross section left is for fines and classified air (release air). Sufficient for the exit room.

Where the outlet chamber, which spirals out in the direction of flow, achieves its maximum flow cross-section on the peripheral surface, that is to say 3 for the origin of the spiral or spiral configuration.
At 60 degrees or one turn, an outlet conduit is connected, which preferably extends tangentially.

Apart from such a technically advantageous arrangement of the spiral outlet chamber, it is achieved that the bearing housed in the projection axially inward is easily accessible from the outside. In the circumferential region where the starting point or the starting point of the outlet spiral portion or the outlet spiral portion is relatively large, the constituent height in the axial direction becomes small.

Since the rotor shaft is lighter and thinner in proportion to the smaller distance between the bearings, the space required for the bearings is correspondingly smaller. In the same situation, the forces generated are smaller, so that a correspondingly smaller cross section or wall thickness is sufficient.

The spacing between the rotor shaft bearings is such that the radial arms connecting the end face ring of the classifier rotor with the rotor shaft are inclined inward to reduce the spacing between both bearings. Can be further reduced by

In particular, in the structure of the present invention, the outlet chamber surrounding the bearing expands outward in the axial direction in a spiral shape or a spiral shape.

The classifier rotor can be arranged horizontally or vertically. When placing the classifier rotor horizontally,
The granular mixture to be classified is very simply fed with the classifying air into the classifier chamber, that is to say that the granular mixture is already relatively fine, so that coarse particles are also carried by the classifying air stream. A large hopper-shaped outlet chamber is provided below the classifier rotor, in which the flow velocity is strongly reduced, so that coarse particles fall downward into the outlet hopper.

For the coarse-grained mixture to be classified,
It is advantageous to arrange the classifier rotor vertically. In this case, the mixture to be classified can, as usual, be introduced from above into the classification chamber surrounding the rotor.

On the lower end wall of the housing, a plurality of hopper-shaped coarse particle outlets are also opened in the classification chamber, and the classification chambers extend over a part of the peripheral surface.
The bottom surface of the classification chamber can also be provided with a hard, wear-resistant and at the same time smooth coating, for example a ceramic light lubricant. The more the surface slides, the smaller the slope of the surface,
This results in a lower axial height.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

The centrifugal classifier according to the present invention has a vertically arranged substantially cylindrical housing 1 in which a classifier rotor 2 is rotatable. Housing 1
Has an inlet 3 for classified air which extends tangentially over the entire height. A guide vane ring 5 is provided at a distance from the housing outer wall 4 in the radial direction. Further, a thin plate ring or a rotating blade ring 6 of the classifier rotor 2 is provided at a distance from the guide blade ring 5 in the radial direction. A granular mixture separated from above is placed in a cylindrical ring-shaped classification chamber 7 formed between the guide blade ring 5 and the rotary blade ring 6. An annular passage 8 for sucking the granular mixture is provided above the classification chamber 7, and a connecting pipe piece 9 is joined to the annular passage 8.

The rotary vane ring 6 is mounted between an upper end face ring 10 and a lower end face ring 11 from which an arm 13 extending substantially radially extends from the axis of the classifier rotor 2. It sticks to 14 and extends to boss 15.
A central retaining ring 10a is additionally provided to reinforce the rotary vane ring 6, which retaining ring is likewise associated with a radially extending arm 13a and which also has a boss 15a.
Are fixedly connected to the rotor shaft 14.

At both end face sides of the classifier rotor 2, there is an outlet chamber for discharging one fine granule and one classifying air, respectively.
17,18 are provided. The gap between each end face ring 10,11 of the classifier rotor 2 and the ring-shaped housing wall facing it is such that coarse particles from the classifying chamber 7 enter the outlet chambers 17,18 for fine particles and classifying air. Sealed so that it cannot be reached. For this reason, in each of the outlet chambers 17, 18 for both fines and classified air, there is one annular passage 16 with connection holes 16a distributed over the circumference.
Is provided.

According to the invention, the upper fine-grain and classified-air outlet chamber 17 and the lower fine-grain and classified-air outlet chamber 18 each have one central axially extending inward portion. It has a projection 19, 20 in which a bearing 21, 22 for the rotor shaft 14 is fitted, respectively.
This results in a much shorter distance between the two bearings 21, 22 than in the prior art, and a correspondingly shorter and lighter rotor shaft.

The radial arm 13 between the end rings 10 and 11 and the rotor shaft 14 is inclined inward so that both bearings 21 and 22 can be displaced further inwards, In short, the rotor shaft is made even shorter.

The bearings 21 and 22 are sealed to the inner chamber by annular gap seal members 24 and 25, and the annular gap seal members are provided with cleaning air passages 26 provided in the shaft.
The cleaning air is supplied axially and radially via the.
Corresponding to the conical bearing housing, a conical ring 27 is provided on each of the end rings 10, 11 so that the flow is advantageously guided and an additional sealing gap is created.

Two fines-outlet chambers 17, 18 for classified air
Are respectively arranged between the cylindrical outer annular wall 29, the cylindrical inner annular wall 30 and these annular walls 29, 30 and are spirally or spirally inclined outward in the axial direction. Alternatively, it is surrounded by a rising wall surface, that is, a circular ring-shaped end wall 31 in a plan view. A bearing 21, 22 for the rotor shaft is housed in the inner annular wall 30 or in the projections 19, 20 respectively. The bearing is easily accessible from the side in the peripheral region where the outlet helix begins.

An annular passage 8 for the admission of the mixture radially outward of the top is adjacent to the outer annular wall 29. According to FIG. 2, the connecting piece 9 is inclined and tangentially aligned with the annular passage 8. The lower side of the annular passage is provided with a spiral-shaped section 8a which is widened in the flow direction, so that the classification material is distributed evenly over the circumferential surface.

A ring-shaped plate 33 or a pedestal is provided on the upper side of the outlet chamber 17 for the upper fine particles and classified air, and a motor or a driving device is incorporated in this plate. A thrust bearing 34 is provided at the upper end of the protrusion, and the thrust bearing bears the weight of the classifier rotor.

By providing the window 32 on the side of the protruding portion 19, the bearing 21 and the seal member 24 can be easily approached even when the drive device is arranged as described above. This window is a plate
It is provided below 33 and above the bearing 21.

On the opposite side, that is to say on the lower side of the housing, four hopper-shaped outlet chambers 35 for coarse particles are provided, which outlet chambers 35 each extend over a quarter of the circumference and Between these outlet chambers 35, the lower bearing 22 can be easily approached from the side.

For this reason, each of the four coarse-grain outlet chambers 35 has an inner wall 35a and an outer wall 35b protruding outward in the vertical direction, and an outlet connecting pipe piece 35e extending in the radial direction. It is provided with walls 35c and 35d that are inclined toward each other.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vertically arranged centrifugal classifier according to the present invention.

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

3 is a cross-sectional view taken along the line III-III in FIG.

4 is a cross-sectional view taken along the line IV-IV in FIG.

FIG. 5 is a side view of the centrifugal classifier.

[Explanation of symbols]

 1 housing 2 classifier rotor 3 inlet for classifying air 5 guide vane ring 6 rotating vane ring 7 classifying chamber 8 annular passage 9 connecting pipe piece 10 end face ring 11 end face ring 13 arm 14 rotor shaft 17,18 fine particles-classifying air Outlet chamber 19,20 Projection 21,22 Bearing 24,25 Annular gap seal member 26 Washing air passage 29 Outer annular wall 30 Inner annular chamber 31 End wall 35 Coarse grain outlet chamber

Claims (5)

[Claims] A classifying air inlet (3) extending tangentially over the height of a classifier rotor (2) in a substantially cylindrical housing, the rotor shaft having axial ends at both ends. A fine classifier-in a centrifugal classifier of the type extending outward through an outlet chamber for classifying air, the diameter of said outlet chamber being approximately equal to the diameter of the classifier rotor, each said outlet chamber (17 , 18) has a protrusion (19, 20) extending inward in the axial direction, and the bearing (21, 22) for the rotor shaft is accommodated in this protrusion, and the bearing (21,
Centrifugal classifier, characterized in that the outlet chamber (17, 18) surrounding 22) expands in a spiral or spiral shape outward in the axial direction. 2. Radial arms (13) connecting the end rings (10, 11) of the classifier rotor with the rotor shaft (14) are directed inwardly towards each other in order to reduce the distance between the two bearings. The centrifugal classifier according to claim 1, wherein the centrifugal classifier is inclined. 3. A plurality of coarse-grain collecting chambers and outlet chambers (35) each having a substantially wedge shape in a side view and extending over a part of the peripheral surface are provided on the lower side of the housing. The centrifugal classifier according to claim 1 or 2. 4. An outlet chamber for each fine granule-classified air.
In (17, 18), an annular passage (16) for supplying cleaning air to each one sealing member is provided with an end face ring (10,
The centrifugal classifier according to any one of claims 1 to 3, which is provided between 11) and a housing wall facing the same. 5. The lower side of the annular passage (8) for receiving the classification product has a section (8a) which extends spirally along the flow direction in order to distribute the classification product uniformly over the peripheral surface. The centrifugal classifier according to any one of claims 1 to 4, wherein