HRP20020016A2 - Screen with slit-shaped or elongated apertures - Google Patents

Description

The invention includes a sieve with openings in the form of cracks or slits, which are limited on both sides by parallel profiled logs.

In the preparation of ores that are followed by norms, there is a prerequisite that the grains of a certain fraction must have a certain shape. Thus, for example, according to DIN 4226, it is specified that the part of poorly formed grains of one fraction must not exceed a certain percentage.

Ill-shaped grains are those with a length-to-thickness ratio of 1:3 or more.

Unfavorably shaped grains cannot be prevented from appearing in nature with gravel, but also with broken materials. These unfavorably shaped grains have a negative effect on the strength of concrete, that's why the standard allows only a certain proportion of unfavorably shaped grains. In order to reduce the proportion of unfavorably shaped grains of one fraction during the sieving process, sieves with openings in the form of cracks or slits are used today, after which the upper surfaces of the logs between the slits are flat or flat.

In any case, this is favorable, so the rod-shaped material will sift through and only in a limited proportion, but it is not favorable to separate it into flat material in the form of tiles.

The task of the invention is to separate the unfavorably shaped material, both in the form of sticks and in the form of tiles, safely from the rest of the screening material in one grain fraction.

In terms of the invention, this task will be solved so that the upper side of the log is made in the shape of a roof or is rounded.

Since the upper side of the log is designed as a roof or rounded, the access of unfavorably shaped grains through the openings of cracks or slits will be facilitated.

Such sieves have a special advantage because they can be produced in an open casting process (open form), in a closed form of casting and even under vacuum (closed form), but also by spraying.

They can be advantageously used in the construction of the sieve surface system in connection with the blind floor.

In addition, a further task of the invention is to capture and separate unfavorably formed grains from the useful fraction. Today's practice is to insert unfavorably shaped grains into the next smaller fraction after sorting or to install another sieve for sorting.

In order to prevent unfavorable grains from going to the next fraction and to avoid the installation of another sieve, it is suggested to install a blind floor below the said sieve, on which unfavorable shaped grains would fall and from which they would then be drained separately.

The blind floor can be made of metal or reinforced elastomer-material, or else of pure elastomer with high strength, in order to avoid material collection due to its elasticity.

Advantages of the invention are set forth under the claims.

Examples of embodiments of the invention are listed under the claims and will be described as follows. They show:

Sl. 1 Sieve according to the invention (sieve for flat grains) in three views

Sl. 1a Sieve for irregular grains with conical logs and conical cracks where the cracks spread in the direction of transport.

Sl. 1b Sieve for irregular grains in the so-called transverse installation system

Sl. 2 Sections through differently shaped logs

Sl. 2a Single log with spacers for the sieve system, on the sides of which there are spacers to ensure spacing

Sl. 3 Three views of the frame on which the sieve is tensioned according to the invention

Sl. 4 Vertical section through the sieve floor system with the sieve according to the invention

Sl. 5 Vertical section through the bottom of the sieve

Sieve (sieve for flat grains) 1 shows several parallel logs (5) which form gaps (4) between them of the same width as the sieve openings.

The widths of the gaps and the widths of the logs, which are therefore selected, also depend on the size of the separation of the grain size of the fraction from irregularly shaped grains. Logs (5) end on both sides in transverse supports where the logs (5) are laid in the direction of transport (9). Between the two cross supports (10) there are also cross ribs (11) attached under the log (5), specially shaped by welding or gluing. Transverse supports and transverse ribs as well as logs are made, for the sake of advantage, from polyurethane, while the logs (5) are reinforced (6) from a very strong and elastic material, especially glass fiber, Armid or Kevlar.

The advantage is if the logs (5) are getting narrower in the direction of transport, so the distance becomes wider and thus not a single flat-shaped grain will be able to be retained.

As shown in Fig. 2 presented, the upper side of the log (5) and thus the upper surface of the log (5), on which the screening material first falls, is rounded or roof-shaped so that the gap (4) formed by the log (5) narrows downwards. Because of this, the unfavorably shaped elongated grains from the screening material will be moved parallel to the transport direction, which will make the passage through the gap visibly easier. In addition, the log can have a quadrangular section with a rounded upper side, but in the form of a roof as well as a trapezoid. In addition, the section can be round, oval or even triangular.

It is advantageous if the profile of the log (5) in the lower part is narrowed downwards from the widest point in order to avoid pinched / retained grains.

It is also beneficial if the profile of the log is slightly parallel or conical at the widest point and only then beveled more strongly, in order to increase the time of use of one sieve for flat grains.

In Fig. 1, the sieve shown will be tensioned in the frame (3) made of polyurethane, which is shown in Fig. (3) whose internal dimensions are slightly larger than the external dimensions of the sieve (1), so that the sieve (1) is tensioned in the frame (3). In addition, the sieve is made shorter than the internal dimensions of the frame (3) - up to 2%, especially 0.5 to 1.0% smaller dimensions.

The frame will be inserted and fixed on the lower structure 12, which has an intermediate profile (13).

Beneath the sieve (1) for flat grains, due to advantages, a blind floor (7) will be attached to the lower structure (12) in order to receive and remove the rotten grains.

Sl. 5 shows the application of such a sieve in a sieving machine, at the end of which the entire surface of the sieve in the transport direction first has sorting sieves (14) and (15) and only at the end a sieve for flat grains (1), for the sake of purpose, with an inserted blind floor ( 7). The blind floor can be installed pressed or bolted or welded or even attached with a custom element. Unfavorably shaped grains (16) will be removed from the blind floor (7) and fraction grains (17) from the sieve for flat grains (1).

Such sieves for flat grains can also be used for the entire sieving surface.

Claims (14)

1. Sieve (1) with openings (4) in the form of cracks or slits that are limited by parallel profiled logs (5), characterized by the fact that the upper sides of the logs (5) are made in the form of a roof or are rounded. 2. Sieve according to claim 1, characterized in that the logs (5) are arranged in the direction of transport (9). 3. Sieve according to claim 1 or 2, characterized by the fact that the logs (5) after 10 to 20 -ero width of the gap are mutually supported with a transverse rib (11) and spaced apart. 4. Sieve according to claim 3, characterized in that the transverse rib (11) is located below the upper surface of the sieve. 5. Sieve according to claim 3 or 4, indicated by the fact that the logs (5) are provided with tensile strength and elastic reinforcement (6), especially made of glass fiber, armide or clover. 6. A sieve according to one of the above-mentioned requirements, indicated by the fact that it is made of an elastomeric material, especially polyurethane. 7. Sieve according to one of the above-mentioned requirements, indicated by the fact that it is mounted under tension on one frame. 8. A sieve according to one of the above-mentioned requirements, indicated by the fact that it is directly mounted, especially with one plug-in system, on the lower structure (12). 9. Sieve according to one of the above requirements, indicated by the fact that it is made shorter than the frame (3) - up to 2%, especially 0.5 to 1.0%. 10. Sieve according to one of the aforementioned requirements, indicated by the fact that it is made shorter than the divisional measure of the lower structure. 11. Sieve, according to one of the aforementioned requirements, characterized by the fact that it consists of individual longitudinal profiles (Fig. 2a) that have plug-in profiles at their ends and/or in the middle that can be attached to the frame or system of the lower structure. 12. Sieve according to one of the above-mentioned requirements, characterized by the fact that the blind floor (7) can be mounted, especially plug-in, between the sieve (5) or the lower structure system. 13. Sieve according to claim 12, characterized in that the blind floor is attached to the lower structure system with screws or welded. 14. Sieve according to claim 12 or 13 characterized in that the blind floor is upgraded with a connecting profile 13.