FR3055226A1 - PANEL FOR SCREENING MACHINE HAVING WEAR DETECTION - Google Patents

Abstract

Panel for a screening machine intended for sorting according to their dimension of elements (4) coming on it, this panel made of one or more synthetic materials, comprising meshes of dimensioned size, being characterized in that it comprises at least one lower layer having a first color, and above at least one wear layer having a second color different from the first.

Description

(54) PANEL FOR SCREENING MACHINE HAVING WEAR DETECTION.

(© Panel for a screening machine provided for sorting according to their dimension of elements (4) coming above, this panel produced in one or more synthetic materials, comprising meshes of calibrated dimension, being characterized in that it comprises at at least one lower layer comprising a first color, and above at least one wear layer comprising a second color different from the first.

FR 3 055 226 - A1

i

The present invention relates to a panel for a screening machine, for sorting elements such as fragments or particles.

The screening of materials is a mechanical sorting operation which allows, by scrolling elements on a screener, also called screening machine, to separate these elements according to their sizes.

For this, a screening machine comprises one or more panels, generally flat, having holes or meshes of calibrated dimension on which the fragments or particles of materials pass. In particular, the panels can be tilted to allow a natural descent of the materials passing over it by gravity. They can have a vibratory movement to facilitate the advancement and descent of these materials.

By passing over the panels, the fragments of the smallest materials pass through the meshes of these panels, the largest remaining above, which performs a sorting according to a maximum caliber predefined by the size of the meshes.

The screeners can include, in the direction of advancement of the fragments, several successive panels in stages having increasingly smaller meshes, which makes it possible to obtain a series of batches of elements corresponding to calibrations included in ranges. smaller and smaller.

This is done in particular in sorting of minerals such as aggregates or fragmented rocks, which are carried out in particular in mines, quarries or sand pits.

We also carry out sorting of plants such as grains or flour, in particular in the food industry. Sorting of any other type of material can be carried out, such as manufactured objects produced in bulk, for example glass beads.

Sorting is also widely used in the household and industrial waste recycling industries.

The screeners may in particular comprise a metal surface comprising the meshes, such as a perforated sheet, a grid or a wire mesh.

Some other types of screeners have a surface, also called a panel, made of a synthetic material, such as polyurethane, rubber, or a mixture of synthetic materials. This panel can be produced by different methods of molding the synthetic material, making the meshes directly, or by cutting a sheet of this material to make the holes.

A problem that arises for panels made of synthetic material is that depending on the type of material passing over it and the shape of the fragments or particles, as well as the conditions of use such as the speed of passage of these elements, there is wear of the surface and the contour of the meshes which can sometimes be rather fast.

Indeed the movements of the fragments or particles can cause, for the synthetic material of the panel, abrasion, tears or tears, which strongly depend on the nature and the shape of these fragments. In particular minerals such as sand are very abrasive, metal or glass waste can be sharp

There is then a wear of the mesh outline defining the calibration, and an enlargement of these holes which results in a deterioration of the quality of sorting by letting larger elements pass. It is thus possible to obtain, beyond a maximum level of wear of the panel, a non-conformity of the sorted lot.

One solution to remedy this problem consists in periodically carrying out an inspection of the panels, which can be visual, or with a means of measuring the dimensions of the meshes, such as a calibration pad, to detect a sufficient level of wear which requires the change. of panels.

However, this inspection requires the shutdown of the screening plant as well as a certain amount of control time, which entails costs. Close access to the panels for near vision is in some cases difficult. In addition, the visual end-of-life assessment of the panel can be subjective, and left to the discretion of the controller, which does not guarantee a precise level.

Another solution is to systematically exchange the panels after a defined period of use, so as to guarantee that a critical level of wear has not been reached. However, this solution involves the risk of changing too soon some panels which are not worn enough and which would not have worked under conditions of severe use, which increases the costs.

The object of the present invention is in particular to avoid these drawbacks of the prior art.

To this end, it offers a panel for a screening machine provided for sorting according to their dimension of elements coming above it, this panel produced in one or more synthetic materials, comprising meshes of calibrated dimension, this panel being remarkable in that it comprises at least one lower layer comprising a first color, and above at least one wear layer comprising a second color different from the first.

An advantage of this panel is that by choosing a thickness of the wear layer corresponding to a wear level which enlarges the mesh sufficiently to reach an acceptability limit of the calibrated dimensions, wear of the surface layer revealing the different color of the lower layer, enables rapid and remote visual inspection to objectively detect the end of life of the panel.

It is thus possible, thanks to a simple and rapid control, not requiring any special qualification for the personnel, to decide to change the panel only when it is necessary, which limits the costs and makes it possible to guarantee optimum sorting quality.

It should be understood that the surface of the lower layer may be equal to or less than that of the panel.

The panel according to the invention may further include one or more of the following characteristics, which can be combined with one another.

Advantageously, the wear layer has a constant thickness over the entire panel.

In particular, the wear layer may have a thickness which is smaller than that of the lower layer.

According to one embodiment, the wear layer is assembled on the lower layer by overmolding or by gluing. Alternatively, a mechanical assembly can also be envisaged.

In particular, the panel may include meshes having a square section.

The invention also relates to a screening machine intended for sorting elements coming from panels, remarkable in that it comprises panels comprising any one of the preceding characteristics.

The invention further relates to a method of maintaining a screening machine equipped with panels comprising any one of the preceding characteristics, remarkable in that it comprises a step of visual detection of the first color on these panels, then in the case where this first color is detected, a step of exchanging the panels presenting it.

The invention will be better understood and other characteristics and advantages will appear more clearly on reading the description below given by way of example, with reference to the accompanying drawings in which:

- Figure 1 is a schematic view in vertical section of a screen according to the prior art;

- Figure 2 is a top view of a new plastic panel of a screen according to the prior art;

- Figure 3 is a top view of this panel which is worn; and

- Figures 4a and 4b are vertical sectional views of a panel according to the invention, which is respectively new and worn.

FIG. 1 presents a screener comprising an upstream chute 2 receiving minerals of different dimensions 4, coming for example from a sand pit, which are led on an inclined panel formed by a grid 6 having meshes 8 of calibrated width.

The descent of minerals of different dimensions 4 on the grid 6 causes certain small elements 10 to pass through meshes 8, the largest elements not passing 12 being discharged onto a downstream chute 14.

This gives a simple, fast and economical way of sorting minerals, for example to obtain sand or gravel of calibrated size.

FIG. 2 shows a panel 20 provided for a screening machine, forming a plate produced in a panel of a molded synthetic material, having a constant thickness, and rows of meshes 22 of square section.

The panel 20 being new, all the meshes 22 have identical dimensions and flanges forming sharp angles, which makes it possible to obtain the same calibration on the whole of the panel.

FIG. 3 shows the same panel 20 after a period of use, comprising meshes 22 that have more served for the passage of the elements, where the synthetic material is heavily worn. The outline of worn meshes 22 is no longer geometric, and the dimensions of these meshes have increased.

There is then a possibility of passage of larger elements in the worn meshes 22, which after a certain level of wear will not correspond to the desired sorting quality. It will be noted that the wear caused by the elements rubbing against the synthetic material can appear both on the top of the panel 20 and in the thickness of this panel on the contour of the passage formed by the meshes 22.

FIG. 4a presents a panel 20 of overall thickness E, comprising a lower layer 30 of thickness E1 formed by a first synthetic material comprising a first color, and above a parallel wear layer 32 of thickness E2 which is thinner, formed by a second synthetic material comprising a second color.

The panel 20 can be formed in particular by overmolding the wear layer 32 on the lower layer 30, these layers having an identical mesh which is superimposed. The panel 20 can also be formed by the superimposition and assembly of two layers 30, 32 each molded beforehand, having an identical mesh, which are fixed together, for example by gluing.

As a variant, the wear layer 32 can be formed by a thick coating, deposited for example by spraying onto the lower layer 30, or by dipping this lower layer in the second synthetic material before polymerization. In this case, there can be a wear layer 32 which also covers the inner contour of the meshes 22.

FIG. 4b presents the same panel 20 after a fairly significant use, comprising with the passage of the elements wear both on the top and inside the meshes 22.

A central zone 34 where a greater quantity of elements to be sorted has passed, has on the wear a wear the thickness of which is greater than the thickness E2, which has completely eliminated in this zone the upper wear layer 32 The first color of the lower layer 30 then appears above the panel 20 in the area 34.

The meshes 22 corresponding to this central area 34 have dimensions no longer corresponding to the requested calibration.

A simple and rapid visual inspection above the panel 20, without tools, makes it possible to detect without hesitation by the first apparent color the critical level of wear of this panel. This saves time and limits repairs to the minimum necessary.

Claims (2)

1 - Panel for a screening machine provided for sorting according to their dimension of elements (4) coming above, this panel (20) produced in a 5 or more synthetic materials, comprising meshes (22) of calibrated dimension, characterized in that it comprises at least one lower layer (30) comprising a first color, and above at least one wear layer (32) with a second color different from the first. 10 2 - Panel according to claim 1, characterized in that the wear layer (32) has a constant thickness over the entire panel (20). 3 - Panel according to claim 2, characterized in that the wear layer (32) has a thickness (E2) which is smaller than that of the 15 lower layer (E1). 4 - Panel according to claim 2 or 3, characterized in that the wear layer (32) is assembled on the lower layer (30) by overmolding or by bonding. 5 - Panel according to any one of the preceding claims, 20 characterized in that it comprises meshes (22) having a square section. 6 - Screening machine provided for sorting elements (4) coming from panels (20), characterized in that it comprises panels (20) according to any one of the preceding claims. 25 7 - A method of maintaining a screening machine equipped with panels (20) according to any one of claims 1 to 5, characterized in that it comprises a step of visual detection of the first color on these panels (20 ), then in the case where this first color is detected, a step of exchanging the panels presenting it. 1/2 PRIOR ART / Æ7Æ7Æ7Æ7 / T7 / V7Æ7Æ7, / Λ7Λ7Λ7Λ7Λ7Λ7Λ7Λ7 / / Æ7Æ7Æ7 / T7 / r7Æ7Æ7Æ7 / '/ V7Æ7Æ7Æ7 / V7 / T7 / T7Æ7 / / 2/2