EP1337305B1

EP1337305B1 - Method and device for dry separating light and heavy fractions of a granulometrically presieved building rubble mixture

Info

Publication number: EP1337305B1
Application number: EP01997338A
Authority: EP
Inventors: Angelo Toschi
Original assignee: Pescale SpA
Current assignee: Pescale SpA
Priority date: 2000-11-22
Filing date: 2001-11-21
Publication date: 2006-07-19
Anticipated expiration: 2021-11-21
Also published as: ITMI20002508A1; ATE333313T1; DE60121616D1; IT1320091B1; WO2002041967A1; EP1337305A1

Abstract

A method and device for separating light fractions, in particular longitudinally extending wood (27), from granulometrically sieved rubble mixtures (9), in which on a vibrating panel (3), are arranged a plurality of partition walls (7) defining channels (8) for orienting and longitudinally guiding the rods (27), where is provided a variable size composite opening (13) allowing to from a first curtain (21) comprising the heavy fractions and smaller light fractions, and a second curtain (24) formed by light paper and larger synthetic sheet material fractions and wood "rods" (27) or only by the latter. The subject separating device (1) can be used as an end separating stage, and can practically provide a recovery of the actual end weight due to the residual presence of the light fraction comprising the wood rods (27) to prevent any disposal of in disposal sites, since the rods (27) are cleaned and accordingly can be reused. Moreover, the end inert material, after the above mentioned operation, is cleaner and has an improved value.

Description

Backgound of the invention

The present invention relates to a method and device for dry separating light and heavy fractions of a granulometrically pre-sieved building rubble mixture.
As is known, in processing building rubble mixtures for separating therefrom recovery inert materials to be reused in replacement of natural quarry inert materials, it is very important to remove as far as possible the light fraction components (such as wood, paper, plastics materials and so on) from heavy material fraction components, forming said recovery inert materials (concrete agglomerates, tiles, marble components and so on).
The above mentioned separating operations can be carried out either by wet or dry methods. The wet or flood separation method is conventionally used, for example, in the Netherlands (in which quarries are practically unavailable), to allow the inert materials derived from building rubbles, or recovery materials, to be also used for higher quality applications, requiring a substantially full absence of light fractions. Accordingly, great amounts of water and several processing apparatus are required, the operating cost of which is very high.
Actually prior dry methods for separating light and heavy fractions from building rubble mixtures provide for example, in pre-sieved mixtures having a particle size or granulometry of 30/70 mm, a light fraction weight residue larger than 0.4%, which is considered a high one.
On the contrary the Applicant's method allows to further reduce this light fraction weight residue to 0.2% and it would be very desirable to further reduce this rate and greatly improve the recovered inert material characteristics.
The inventor has found that in his pre-sieved or pre-sorted mixtures, the light fraction weight residue, at the end of the processing cycle, mainly comprises stick or rod-like "wood pieces", which, in a preliminary passage of the rubble material through the crushing mill, are derived from doors, windows and the like, i.e. have been detached from the latter, generally along the direction of the wood grains and at the wood knots, thereby assuming a length pattern of, for example, from about 10-12 cm to 20 cm and more, with small uneven or "rod-like" cross-sections.
Differently from the heavy fraction components, having a pebble gravel or scree pattern, i.e. uneven shapes of substantially ovoidal configuration, in the wood "rods", the size differences between the cross size and longitudinal size are comparatively high, thereby, through a sorting hole having for example a diameter of 60 mm, "rods" having a length of 15-20 cm can also pass.
Accordingly, the above mentioned dry separating methods have not been found suitable, up to present, for separating said "rods" by prior vibrating panels including throughgoing holes or resilient blade elements having a size suitable to provide a desired granulometry, for example of 30/70 mm; moreover, the above mentioned sorting or separation cannot be performed by blowing or sucking devices, unless great powers are used, which, on the other hand, would cause tile portions, i.e. heavy portions, to be blown away or sucked.

Summary of the invention

Accordingly, the aim of the present invention is to provide a separating method and device of the above mentioned type, which is suitable to further reduce, in the separated inert material fraction, the light fraction weight residue, to rates less than the above mentioned 0.2% rate provided by prior methods and devices.
Within the scope of the above mentioned aim, a main object of the present invention is to allow the above indicated results to be obtained by using a very small power amount and without requiring any modifications of prior dry processing systems.
The above mentioned aim is achieved, according to the invention, by a method and a device having the features of claims 1 and 6 respectively.
Further advantageous developments and features of the method and device according to the invention are defmed in the dependent claims.
The method and device according to the invention provide a lot of important advantages.
At first, the subject method and device allow to greatly reduce the light fraction weight residue under said 0.2% rate provided by prior devices, for example by 50% or more of said rate, i.e. a residue rate less than 0.1%, as it will be more apparent hereinafter from the disclosure of some practical examples. A further advantage is that the mentioned results can be automatically achieved, i.e. without using operators for pre-removing the light fractions, as is necessary in the "Dutch" separating or flood method.
The progressively advancing continuous shocks applied to the rods in the longitudinal direction of the vibrating panel, and the pushing forces applied to said rods in their longitudinal feeding direction by greater weight pieces, fed at a greater rate, together with partition walls having wedge sides, provide an advantageous reliable pre-orienting of the rods. Thus, the rods are prevented from being arranged in a cross direction, for example against the partition walls, susceptible to operate as "dam" hindering and stopping the mixture being fed through the orienting passages.
The desired rod separating operation is reliably and automatically achieved by a resiliently flexible edge, for example made of a rubber or the like material, having such a flexibility rendering it undeformable as the light wood rods pass thereon and, in the meanwhile, being deflected under the weight of the heavier and larger pieces bearing thereon, which will consequently fall by gravity through said variable size composite opening.
Moreover, the present invention advantageously provides a light fraction comprising only the longer wood rods, or exclusively said rods, which are supplied in a clean condition and, accordingly, must not be disposed of in disposal sites, but can be used in other applications, for example, advantageously, for making industrial hardboard, cellulose, paper materials and so on.
The provision of an extended receiving region for receiving the rubble mixture therein allows to reliably distribute said mixture substantially in the form of a thin layer, or a single-layer mixture, to facilitate a longitudinal self-orienting of said rods, even if the rubble mixture is fed by conventional conveyor belts or chutes having a comparatively narrow cross-section.
An advantageously designed construction of the separating device according to the present invention, to provide a high separation yield, will be also hereinbelow disclosed.
By performing a pneumatic separation of the lighter and smaller fractions, which is known per se in this field, and which can be performed either upstream or downstream of the separating device according to the invention, a heavy material fraction, or inert material fraction, practically free of light fraction materials and of greater commercial value, is thereby provided.

Brief description of the drawings

Further characteristics, advantages and details of the separating method and device according to the present invention will become more apparent hereinafter from the following disclosure of a preferred exemplary embodiment of the invention, with reference to the accompanying drawings, in which:

Figure 1 is a schematic top plan view of the dry separating device for separating light and heavy fractions of a building rubble mixture;
Figure 2 is a schematic longitudinal cross-sectional view taken along the plane II-II of figure 1;
Figure 3 is a further schematic cross-sectional view taken along the line III-III of figure 2;
Figure 4 illustrates, on an enlarged scale, a detail of the end portion of the subject separating device having a variable size discharging opening, and
Figures 5 and 6 schematically show different instantaneous discharging conditions, respectively related to a first and second separated-material curtains.

Description of the preferred embodiment

With reference to the above mentioned figures, in which like portions are indicated by like references, the separating device according to the present invention has been generally indicated by 1 and comprises a casing 2 and a vibrating panel 3, which is driven, according to the invention, with a reciprocating vibrating motion, in a substantially coplanar plane, by a vibrating assembly, (not specifically shown), including side motor-vibrating devices, (also not shown and which can have any desired construction); the reference 6 indicates stiffening ribs for supporting the mentioned motor-vibrating devices. The vibrating-sieving feeding panel 3 can be made with any suitable construction, for example as a vibrating-feeding device, a vibrating channel and so on. The reference 5 indicates pivoting holes in a bearing construction, not specifically shown, for adjusting the downward inclination of the vibrating panel 3, depending on the composition, moisture contents and so on of the fed rubble mixture, or on other operating parameters.
According to the invention, on the vibrating panel 3 are arranged a plurality of longitudinally extending spaced strip-like partition walls 7, in the embodiment being shown five partition walls 7 defining six orienting channels 8 which, in the shown embodiment, have a width increasing in the mixture feeding direction. Upstream of the partition wall 7 (with reference to the rubble feeding direction F on the vibrating panel 3) on said vibrating panel 3 a first portion 12 for feeding and spreading/levelling the rubble mixture 9, supplied by a channel conveyor belt 11, as conventional, having, for example, a width of 30 cm, and supported by side supporting elements 4 is arranged.
In the shown embodiment, the rubble stream 9 falling from the channel conveyor belt 11 forms a rubble curtain 9A, with which is advantageously associated a pneumatic removal device 10 for removing the lighter portions having a weight smaller than that of the wood rods, for example a blower or sucker device, said removed light portions being then separately collected, in a per se known manner. The removal operation, in particular, will be actuated depending on the desired features of the inert materials and rod fraction, either in combination or not with other downstream performed pneumatic removal operations for removing the light parts, as it will be disclosed hereinafter.
The above mentioned feeding and levelling region 12 is preferably constituted by a metal surface and/or a coating of any other suitable materials having a high sliding friction coefficient, to provide an efficient and quick levelling and feeding of the mixture pieces. A suitable coating can comprise, for example, a rubber, polyurethane or the like material, having a high sliding coefficient.
As clearly shown in the drawings, at the end portion of said partition walls 7 is provided a composite variable size cross opening 13, formed by a free opening 14, of length 14A, and a downstream edge (with respect to the rubble mixture feeding direction F) indicated by 16, having a length 16A and constituted by a resiliently flexible material strip such as a rubber or synthetic material, fixed, along its edge opposite to the free opening 14, to the vibrating panel 3, by glueing, screws or any other suitable manner. The total length of the variable size opening 13 will be, accordingly, 13A = 14A + 16A, where the fall useful length of said variable size composite opening 13 will practically be less, depending on the resilient properties of the flexible edge 16, or depending on its folding inside the opening 13, as schematically shown in figure 5, under the weight of the respective heavy piece 22.
The flexible edge 16 is resiliently yieldable under the weight of the larger pieces 22 of the rubble heavy fraction and, on the contrary, is substantially stable under the small weight of the wood rods 27 or other larger paper and plastics pieces 26. The elasticity features of the flexible edge 16, accordingly, must be fitted to the particle size of the mixture to be respectively processed. Said flexible edge 16, accordingly, can be advantageously of a replaceable type.
In the shown embodiment, the partition walls 7 end downstream of the variable size composite opening 13 and, starting from their downstream edge 17, the end portion 18 of the vibrating panel 3 is downward slanted and ends with a cross edge 19.
With the above disclosed construction, the variable size composite opening 13 will constitute the drop or falling opening of a first mixed curtain 21 comprising the heavy components 22 and smaller light fraction components 23, i.e. passing through the free opening 14. The parts of the larger light fractions, such as paper pieces, synthetic material sheets and the rods, passing through the free opening 14 as a movable "bridge" and bearing on the flexible edge 16, form a second curtain 24 which, accordingly, comprises only the light fractions including paper and synthetic material pieces 26, and the wood rods 27, if a pneumatic separation of the upstream like parts, i.e. that provided on the fed rubble stream 9, has not been yet actuated.
As shown in particular in figure 2, moreover, the front impact side 28 of the walls 7 is formed with a slanted pattern as a lead-in side for raising and rotating the rods 27. The height of the partition wall 7 will be generally larger than the largest particle size of the rubble mixture 9 to be processed, for example of 100 mm for a particle size or granulometry of 30-70 mm. Accordingly, the rods 27, a portion or end of which is urged to slide and raise from said lead-in sides 28 during the feeding thereof, will tend, in falling from said slanted lead-in side, to be arranged on the vibrating panel 3 in a substantially longitudinal arrangement.
With respect to the length of the flexible strip or edge 16, it, according to the invention, varies for example from 50% to 100% of the width of the free opening 14.
With reference to the granulometry or particle size of the rubble mixture to be processed of 30/70, a preferred embodiment of the separating device 1 according to the present invention has, by way of an example, the following size:

a: width of the vibrating panel 3 = 600 mm
b: total length of the vibrating panel 3 = 1,180 mm
c: length of the single-layer levelling portion 9 of the fed mixture 9 = 400 mm
d: length of the partition walls 7 = 780 mm
e: length of the end slanted portion 18 of the vibrating panel 3 = 134 mm
f: total length 13A of the variable size composite opening 13 =100 mm
g: length 14A of the free opening 14 = 60 mm
h: length 16A of the resilient edge 16 = 40 mm
i: height of the partition walls 7 = 100 mm
j: starting width of the orienting channels 8 = 120 mm
j': end width of the orienting channel 8 = 150 mm
k: vibrating assembly suitable for generating reciprocating substantially coplanar vibrations,
l: height difference S between the vibrating panel 3 and the underlying flexible edge 16 = 8 mm.

According to the invention, in addition to the rubble curtain 9A, with the first and/or second curtains 21, 24 is also preferably respectively associated a pneumatic device, for example a blower or sucker device 29, for removing from said first and/or second curtains 21 and 24 the light fractions comprising paper pieces, synthetic sheet pieces, small wood pieces and the like.
The separating device 1 according to the invention, which has been partially hereinabove disclosed, operates as follows:
The rubble 9 mixture curtain 9A is caused to fall onto the levelling portion 12 of the vibrating panel 3, whereas the powdery portion will be previously removed. The individual different typological pieces, schematically indicated, for example, by 22, 23, 26, 27, forming said mixture 9, as they fall on the starting portion 12 of the vibrating panel or belt 3, will be spread apart or levelled both because of the impact on a surface having a high sliding coefficient and of their related rolling movements one above the other occurring in the falling movement and favored by the substantially coplanar vibrations tending to separate from one another said individual pieces, which levelling, moreover, would be facilitated due to the comparatively high width of the mentioned portion 12. As said mixture 9 pieces arrive at the orienting channels or passages 8, the portions of the heavier fractions will be entrained thereby or slide through said channels 8, either directly or by a partial pre-rotating on themselves, as they impact against the lead-in corners 28 of the partition walls 7. The rods 27, because of their comparatively large length, will arrive, in an easier manner, either before or after, to contact the lead-in corners 28 or said partition wall 7 and, under the combined feeding action exerted on said rods by the vibrating panel 3 and adjoining moving portions of the heavier fractions 22, said rods will be subjected to a longitudinal orienting and guiding action as they are fed to the inlet of said orienting and guiding channels 8, and/or through said channels, with a possible raising, rotating and falling, as above mentioned. Thus, said rods 27 can be moved toward said free opening 14 with a position substantially perpendicular to the latter. Under these conditions, said rods 27 tend to by-pass, at first with an overhang arrangement, and then with a movable bridging arrangement, the free opening 14, without hindering, owing to a possible downward inclination of the rod front end portions, a passing of said rods through said free opening 14 and then bearing by their front end portions on the flexible edge or strip 13, which is likewise vibrating with the vibrating panel 3. Thus, the rods 27 are further entrained toward the falling edge 19 of the end length 18 of the vibrating panel 3. A like operation occurs for the paper or synthetic sheet pieces 26 having a length greater than the length of the free opening 14. Thus, the rods 27 and paper and plastic sheet pieces of larger size 26 will form the second curtain 24 which will only comprise longitudinally extending materials of the light fractions.
All the heavier fraction pieces, on the contrary, will fall either directly through the free opening 14 or, if they, as the pieces 22, have a size greater than the considered granulometry (for example 30/70 mm) will fall, under their weight, through the fee opening 14 and will bear on the flexible edge 16, thereby causing a downward bending or deflecting of said edge 16. Thus, the falling surface of the variable size composite opening 13 will be increased, and the larger heavy pieces 22 will fall, possibly together with other smaller pieces of the coming light and heavy fractions, to form a first curtain 21, of a mixed type, if a pneumatic separation on the rubble curtain 9A has not been actuated, since said curtain will comprise both heavy fractions 22 and light fractions 23.
In this connection it should be apparent that the above disclosed falling or entrainment steps of the light and heavy component pieces which has been illustrated as occurring individually and at a given time, can also occur, practically, both separately and jointly, depending on a random arrival of the several component of the mixture 9 at the variable size composite opening 13.
In order to prevent a large heavy piece 22, susceptible to bend the edge 16, from also causing a simultaneous falling into the variable size opening 13 of the rods 27 which would be present at that moment, according to the invention, the flexible edge 16 can be longitudinally cut by cuts 31, defining a plurality of adjoining tabs 32 which can be flexed independently from one another, thereby greatly improving the separating operation efficiency and the amount of rods included in the first curtain 21 will be actually negligible
It should be moreover pointed out that the lighter paper or synthetic sheet pieces 23, 26 could also be advantageously pneumatically removed by using, as known per se, blower or sucker units 29, figures 5 and 6, and related collecting means 29A, the arrows in said figures indicating the entrainment direction of the taken light fractions.
By using said blower or fan devices 10 and 29, it would be possible to advantageously obtain an inert material 33 practically free of light fractions and/or a collection of rods 34 likewise practically cleaned and free of other paper or plastic material light fractions. Thus, it would be possible to greatly increase the commercial value of the obtained inert material and, in the meanwhile, the cleaned wood rods, instead of being directed to a disposal of site, can be reused for making cellulose, paper, paperboard materials for industrial applications and so on.
The actuation of the pneumatic removal means at the rubble curtain 9A and first and second curtains 21 and 24, either individually or in combination at will, will depend both on the rubble mixture 9 composition and on the desired clearness degree of the inert materials and/or rod fraction to be made.
The different operating steps, dry performed on the rubble mixture 9 according to the present invention, and its inventive method, can be easily derived from the above constructional and operational disclosure related to the separating device and its operation. Accordingly, a further disclosure thereof will be omitted and, for further details, reference to the accompanying claims should be made.
Thus, even if optimum results have been provided as above disclosed, by processing a rubble mixture having a particle size of 30/70 mm, it should be apparent that said particle size can be specifically fitted depending on requirements, i.e. not only on different compositions of the rubble mixture to be processed, but also on operating parameters to be set, such as, for example, the rubble feeding speed and flow rate, inclination of the vibrating panel, moisture contents of the mixture being processed, inclusion therein of possible adhesive components and so on, without departing from the scope of the following claims.
In practicing the invention, it would be moreover possible to replace individual parts by other technically and/or equivalent elements, such as, for example, to provide a fan arrangement of the partition walls, tapering toward the variable size composite opening 13, or provide the end portion of the feeding belt 11 with a swinging movement, of flag type, thereby facilitating a distribution into a thin layer of the mixture 9 on the starting part 12 of the separating device 1, and so on, without departing from the scope of the invention.

Claims

A method for dry separating light and heavy fractions of a granulometrically pre-sieved rubble mixture, by using a feeding panel of a vibrating sieve type, said method comprises:
a) a levelling step for levelling into a single layer said rubble mixture fed to a starting portion of said vibrating panel,

b) a preliminary orienting step for longitudinally orienting longer rods by causing said longer rods to slidably impact against partition walls defining guide passages or against components of heavy fractions simultaneously entrained on the vibrating panel or belt,

c) a feeding step for feeding the rubble mixture while guiding/holding in a substantial longitudinal orientation said rods in said guiding passages,

d) a gravity falling step for forming a first curtain including smaller pieces of light fractions passing through a free opening of a variable size composite opening, and portions of the heavy fractions passing through both said free opening and said overall composite variable size opening, the latter being traversed by larger and heavier portions of intended particle size,

e) a cantilever-wise bridging step for movably bridging the free opening of said variable size composite opening by said light portions and longer rods, which, successively, will fall by gravity from the free end portion of said vibrating panel thereby forming a second curtain comprising only light fractions, where in

f) there is moreover provided an optional pneumatic step for removing the lighter fractions of the longest rods to be performed on the rubble curtain upstream of the vibrating panel.
A method according to Claim 1, characterized in that said preliminary orienting step for longitudinally orienting said rods is aided by a raising, rotating and re-falling action on said vibrating panel being performed by a lead-in wedge corner provided on each partition wall.
A method according to Claims 1 and 2, characterized in that said variable size opening has a flexible edge the elasticity of which is so selected as to provide:
a) a resilient bending of said edge under the weight of the largest pieces of the heavy fractions falling by gravity, and

b) a substantially horizontal self-positioning of said flexible edge both as it is not urged, and as it is urged by the longest rods bypassing, as a movable bridge, said free opening of the variable size composite opening.
A method according to Claim 1, characterized in that to said rubble mixture curtain fed on said vibrating panel and to said first and/or second curtains is applied a pneumatic action for removing the light fraction pieces, lighter than the longest rods, such as synthetic material pieces, paper pieces, or small wood pieces.
A method according to one or more of the preceding claims, characterized in that said pneumatic steps for removing said light portions, lighter than the longest rods, to be performed on said fed rubble curtain, and on said first and second curtains, are performed both individually and in any desired mutual combination.
A separating device for separating granulometrically pre-selected heavy and light fractions of building rubble materials, for carrying out the methods according to claims 1 to 5, comprising a vibrating sieve like-vibrating panel (3) for feeding the rubble mixture, for example of a type swingably supported to adjust the inclination of said vibrating panel, and associated vibrating means, wherein:
a) the region (12) of said vibrating panel (3) for receiving said rubble mixture (9) has a width larger than the width of the belt (11) for conveying said mixture (9) thereby providing a thin layer levelling or a single-layer levelling of the fed mixture (9),

b) downstream of said mixture (9) receiving region (12), on said vibrating panel (3) are arranged a plurality of partition walls (7) longitudinally arranged and spaced from one another, defining orienting/longitudinal guide passages (8) for orienting/longitudinally guiding the longest wood rods (27) present in said rubble material,

c) at the end portion of said partition walls(7) is provided a cross composite discharging opening (13) of variable size, defined by a free opening (14) the downstream edge of which is formed by a flexible resilient material edge (16), in single piece or in the form of adjoining tabs (32) suitable to resiliently yield under the weight of the largest pieces (22) of the heavy fraction passing through said variable size composite opening (13), but being substantially self-supporting under the weight thereof and the weight of the longest wood rods (27) or of other largest pieces (26) of the light fractions, so that downstream of said variable size composite opening (13) through the free opening (14) thereof falls said first curtain (21) of mixed fractions, said vibrating panel (3) ends with an edge (19) for allowing a falling therethrough of said rods (27) and light fraction pieces (26) having a length larger than the width of the free opening (14) of the variable size opening (13), which rods (27), and light fraction pieces (26), form a second curtain (24) comprising only the materials of the light fractions, and

d) with at least one of said first and second curtains (21 and 24) and said curtain (9A) of the mixture fed on said vibrating panel (3), preferably with all said curtains (9A, 21 and 24), is associated a pneumatic means (29, 10) for pneumatically removing the light portions (23 and 26) lighter than the longest rods (27), said pneumatic mans (10, 29) being individually driven.
A separating device according to Claim 6, characterized in that the partition walls (7) are provided or arranged so as to form orienting/guiding passages (8) having a width increasing in a longitudinal direction towards the end portion (18) of said panel, and the impact front side (28) of the partition walls is formed as a vertical-plane lead-in beveled side operating as a side for raising, rotating and re-falling said rods (27) on said vibrating panel (3).
A separating device according to Claim 6, characterized in that the length of the flexible strip or edge (16) is preferably from 50% to 100% of the length of the free opening (14).
A separating device according to Claim 6, characterized in that said flexible edge (16) is supported, preferably in a replaceable manner, on said vibrating panel (3) at a height position slightly lower than the vibrating panel (3) upstream of the variable size composite opening (13), so as to safely receive also those rods greater than the free opening (14) with end portions slightly downward slanted.
A separating device according to Claim 6, characterized in that said partition walls (7) extend beyond the first variable size composite opening (13).