JPS6366275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for classifying fine-grained, fluid, dry bulk materials such as abrasives and shot materials.
The present invention relates to a multi-stage mechanical sieve in the form of a projection sieve, which can be classified into a number of particle size classes in the process.

Multistage mechanical screens designed as projection screens are already known. One known multi-stage mechanical sieve of this type consists of several sieve stages mounted one above the other on a basic frame and inclined at an angle of 30 DEG to 40 DEG to the horizontal.
A vibrating head is attached to the housing. Below the sieve cloth there is a shaft with a striking rod that forces the sieve cloth to vibrate via a ram and a ram head (West Germany).
Remscheid Rhewum).

In other multistage mechanical sieves designed as projection sieves, the drive is provided by an electromagnetic oscillator, the vibrations being transmitted directly to the sieve cloth by means of a ram (ram vibrating mechanical sieve, Chemieanlagen Stassfurt).

Although these multistage mechanical sieves formed as projection sieves have good performance, they cannot return the material.
It has the disadvantage that it is not suitable for applications that require classification into multiple particle size classes in one step.

The return of the material is hindered, in particular, by the sieve racks vibrating in the direction of the vertical longitudinal plane, and thus the material being transported in an oblique direction. Returning the material is therefore not possible, since this must be carried out opposite to the direction of projection of the material. This can certainly be countered by increasing the slope of the return stage, but this increases production costs and, despite the strong slope of the return stage, material will accumulate, making it difficult to reliably achieve the desired effect. I can't.

Another disadvantage of multistage mechanical sieves of this type is that they can be used to classify only up to six particle size classes in one step. For example, in applications that require classification into a large number of particle size classes, such as grades 10 to 25 in the production of abrasives or shot materials, it is therefore necessary to install and operate several multistage mechanical sieves of this type in parallel or in series. Must not be. Additionally, equipment for transporting materials from machine to machine and equipment for consolidating materials is required. This type of application therefore has high equipment costs, as well as operating, care and maintenance costs, and requires a large installation space.

There are no known multistage mechanical sieves in the form of projection sieves, which can be classified into multiple particle sizes in one step over long periods of continuous operation, with a return operation opposite to the direction of transport of the material.

Furthermore, multi-stage mechanical sieves which operate as flat sieves are also known, which consist of a sieve stage, a blind stage and a return stage, which are attached to a frame, and which vibrate the superimposed sieve thus formed as a whole. The slope of this superimposed sieve can be adjusted depending on the desired residence time of the material on the sieve shelf and the fluidity of the material. The drive is carried out by means of horizontally acting eccentrics (Ludwigshafen, West Germany).
Engelsmann Regulasiel).

Although this multi-stage mechanical sieve allows material to be returned, this type of multi-stage mechanical sieve, which operates according to the plane sieve principle, can also classify only up to six particle size classes in one step. Flat sieve machines generally have the disadvantage that the sieve shelves are moved only in the plane of the sieve, so that only gravity acts under the sieve, which causes movement through the sieve shelves. As the particle size of the material becomes finer, even more adhesion forces act on the bottom of the sieve, and these forces may become so great that the slight gravity of extremely fine particles cannot overcome them.
This has a negative effect on the separation accuracy in the fine grain range of the sieve, which leads to a reduction in quality. In addition, a large area of clogging may occur on the sieve shelf, reducing sieve performance.

For this reason, the problem of sieving to classify a large number of particle size classes cannot be solved using mechanical sieves of this type without the expensive parallel or series operation of several multistage mechanical sieves.

The object of the invention is a multi-stage mechanical sieve designed as a projection sieve, with which a number of multi-stage mechanical sieves can be used to solve sieving tasks requiring the classification of bulk materials into a number of particle size classes. The object of the present invention is to develop a system that can avoid parallel and series operation as much as possible and keep equipment costs, operation, care, and maintenance costs low.

The reason for the parallel and series operation required when solving the sieving problem in which bulk materials need to be classified into multiple particle size classes is that known multi-stage mechanical sieves designed as projection sieves do not allow material to be returned. These multi-stage mechanical sieves can only classify up to six particle size classes in one step, since those designed as flat sieves do not operate with sufficient separation accuracy in the fine particle size range. The object of the present invention is therefore to develop, for the first time, a multistage mechanical sieve in the form of a projection sieve, which allows the material to be returned against the transport direction and which operates with high separation accuracy in all particle size ranges.

According to the invention, this problem is achieved by mounting an originally known oscillator slidably and rotatably on the superimposing sieve so that its line of action spans the superimposing sieve at an angle of 45° to 85° with the horizontal. The grooves are arranged so that the grooves can freely vibrate at an angle of 0° to 85° with respect to the vertical, preferably 0° to 45°, and are inclined at an angle of 0° to 30° with respect to the horizontal. This is solved by connecting the frame in an articulated manner.

It is further characterized in that the ends of the grooves open into vertical channels in the superimposed sieve, and that several grooves are interconnected at their ends.

The multi-stage mechanical sieve consists of a superimposed sieve, an oscillator and a particle outlet. In the superimposed sieve, a sieve stage, a blind stage, and a return stage are arranged tightly stretched using a tensioning frame and a tensioning device. An oscillator is slidably and rotatably mounted on the superimposed sieve or on a separate vibrating frame, the projection angle and the line of action of the oscillator being adjustable from 45° to 85° with respect to the horizontal.

The return stage has a groove suspended on a spring so that it can freely oscillate vertically. The groove is inclined at an angle of 0° to 30° with respect to the horizontal and is articulated at the end with the frame of the return step. Several grooves can be interconnected at their ends. The superimposed sieve as a whole is vibrated by an oscillator. Returning the material against the transport direction is ensured by transmitting vibrations to the freely vibrating groove. The present invention will be explained in detail below using examples and drawings.

Embodiment The multi-stage mechanical sieve shown in FIG. 1 consists of a superimposed sieve 1 mounted on a vibrating frame 2. Inside the superimposed sieve 1, there is a sieve-and-blind stage 3.
and the return stage 4 are arranged in an overlapping manner. The sieve and blind stage 3 and return stage 4 consist of a basic frame 5, a side frame 6, and a lid frame 7.
and are mutually supported by a tensioning device 8.
A superimposed sieve 1 resting on a vibrating frame 2 is mounted on a spring 9. An oscillator 10 is slidably and rotatably attached to the vibrating frame 2. Therefore, the line of action of the oscillating force of the oscillator 10 on the superimposing sieve 1 can be adjusted to form a projection angle of 45° to 85° with the horizontal. The sieved particles are discharged through the particle outlet 12.

As can be seen in FIGS. 2 and 3, several grooves 13 are provided in the return stage 4 and are inclined at an angle of 5 DEG to the horizontal, opposite to the material transport direction A. These grooves are suspended vertically and freely oscillating on springs 14 and are articulated 16 at their ends to the frame 15 of the return stage 4.

Several grooves 13 to organize the flow of material
The ends of the two can be connected to each other. The superimposed sieve 1 firmly mounted on the vibrating frame 2 is an oscillator 1.
0 causes the whole to vibrate. By changing the surface of the oscillator 10 that acts on the vibrating frame 2 and by changing the projection angle α, vibration can be applied to the superimposed sieve 1 depending on the sieving problem to be solved.
The return of the material to the sieve rack, contrary to the transport direction A of the material, is ensured by the vertical vibrations of the grooves 13 caused by the vibrations of the superimposed sieves 1.

The multistage mechanical sieve according to the invention is particularly suitable for solving sieving tasks in which bulk materials are to be classified into a number of particle size classes in one step. It is particularly suitable for the classification of abrasive and shot materials, but is not limited to this use.

The solution according to the invention allows for the first time the projection of material in a multi-stage mechanical sieve designed as a projection sieve.
and succeeded in ensuring that the material was returned to the sieve and blind trays opposite to the direction of transport. Depending on the type of vibrational excitation in the superimposed sieve, high separation accuracy can be achieved even for fine-grained materials. Moreover, up to 25 particle size classes can be classified in one step in this type of multistage mechanical sieve. The conventional parallel and series operation of several machines is therefore no longer necessary when solving this type of sieving problem. This leads to a reduction in installation area and space requirements and to savings in equipment costs and operating, care and maintenance costs.

[Brief explanation of drawings]

FIG. 1 is a side view of the multistage mechanical sieve, FIG. 2 is a sectional view of the return stage, and FIG. 3 is a top view of the return stage. 1...Superimposed sieve, 2...Vibration frame, 3...Sieve and blind stage, 4...Return stage, 5...Basic frame, 6...Side frame, 7...Lid frame, 8...Tension device , 9...spring,
10... Oscillator, 11... Line of action, 12... Particle outlet, 13... Groove, 14... Spring, 15...
Frame, 16... Articulated connection, 17... Connection, α...
Projection angle, A... transport direction.

Claims (1)

[Claims] 1 A projection type multi-stage mechanical sieve is constructed by stacking a plurality of sieve stages and blind stages to form a multi-layered sieve stage and attaching it to a frame, and the frame is activated by an oscillator attached to the frame. In the projection type multi-stage mechanical sieve, the multi-layered sieve stages are vibrated to move the material to be sieved over the sieve of each sieve stage from the supply side to the discharge side. At least one return stage is provided between the sieve and the return passage extending from the discharge side to the feed side of the sieve, the return passage being articulatable and inclined at an angle of 0 to 15 degrees with respect to the horizontal. 1. A projection type multi-stage sieve, characterized in that the return passage has a support frame that supports the oscillator, and the return passage is configured to freely vibrate vertically in response to vibrations from the oscillator. 2. The projection type mechanical sieve according to claim 1, wherein the passage opens into a vertical conduit at its end. 3. The projection type mechanical sieve according to claim 1, wherein the projection type mechanical sieve is connected to each other at the ends of the passages.