Heated mixer for composite materials with controlled output

Description

[0001] The present invention relates to the field of recycling and recovery of factory and construction site waste in the context of waterproofing materials and systems, in particular in relation to bituminous waterproofing membranes, and relates to a heating mixer with regulated output, an installation for treating and recovering composite products based on thermoplastic materials and a method for controlling such an installation.

[0002] As part of the general trend towards seeking possible recovery of waste, a growing demand, which is currently not satisfactorily addressed, either technically or economically, concerns factory waste and especially construction site waste in the field of waterproofing, particularly in relation to bituminous waterproofing membranes.

[0003] One of the major problems encountered, and to date not satisfactorily resolved in the state-of-the-art proposals, concerns the presence, often intertwined with the material to be recovered (essentially the bituminous binder), of non-recoverable pollutants, in particular hard solid particles, of the metallic, mineral or other type (originating from assembly or fixing elements, covering layers, surface protection layers, or similar).

[0004] In particular, deconstruction waste from the renovation market currently represents a significant potential source of waterproofing membranes to be treated, estimated to date at around 100,000 tonnes per year in France (estimate by the French Waterproofing Trade Union), this source being renewed each year. The cost of burying this waste has been increasing for many years, and this trend is expected to continue, especially since no real industrial solution for treating deconstruction waste is currently available.

[0005] There is therefore a strong and constant demand to try to find an industrial solution to reduce the consumption of a fossil resource which is becoming scarce and which would be truly efficient in the recycling of waterproofing membranes.

[0006] However, the composition and therefore the treatment of this waste are complex, because when repairing building roofs, it is possible, and common practice, to superimpose several layers of membranes on top of each other, and to assemble them by gluing or welding, and to fix them mechanically to the support.

[0007] However, after a certain number of repairs (depending on the legislation of the country concerned in this matter), it is technically necessary and administratively obligatory to remove the entire roofing system and install new waterproofing on the roof (framed; roof terrace or other) in its raw state.

[0008] The waste recovered at the end of this total removal operation, known as deconstruction waste, mainly comprises laminates of bituminous membranes joined together and with various types of finish, including slate granules, sand, complexed aluminum sheets (PET-alu). This waste may also contain solid pollutants, including insulation (PUR, XPS, mineral wool, wood fibers, etc.), metal parts (mechanically fixed metal membrane hooks, saw blades for cutting waste, etc.), and other miscellaneous detritus associated with the storage of a waste recovery skip on a construction site (pebbles, stones, cans, etc.).

[0009] Thus, in relation to the request expressed above, the composite products which it would be desirable to be able to process within the scope of application concerned by the invention essentially comprise: mainly bituminous membranes containing a reinforcement e.g.: PNT non-woven polyester or glass veil...), a bituminous binder (e.g.: polymer and bitumen, additives, filler...), a surface finish (e.g.: sand slate granules, complexed aluminum sheets...). Potentially these membranes are agglomerated in successive layers fused to each other during installation by heating, and thus forming plates (Dimensions of the recovered plates: ~ 1 mx ~1 mx (1 to 20) cm). Alternatively, the products to be treated may include rolls of bituminous membranes from production (second choice) or manufacturing offcuts from such rolls. Alternatively these membranes can be pre-crushed. solid pollutants of various kinds: insulation (PUR, XPS, mineral wool, wood fibers...), metal parts (mechanically fixed metal hooks of membranes, saw blades for cutting waste...), or various debris (sand, gravel, pebbles, stones, cans, etc.).

[0010] At the end of at least a first phase of treatment, the outgoing product (output) should include in particular smooth bitumen-based binders, also incorporating polymers and dispersed particles or fiber fragments, preferably with a dimension of less than 100 µm.

[0011] Furthermore, while the inputs are at room temperature (typically between 0°C and 30°C), the output of this first treatment should, by adequate transformation of the inputs, be at least at the temperature of use, of the bituminous and thermoplastic binders, namely between 150°C and 200°C typically.

[0012] Such a state of the output facilitates its subsequent treatment, in particular the extraction of macroscopic solid pollutants, not or insufficiently reduced during this first phase of treatment (such as pebbles, stones, gravel, screws, bolts, rivets, nails, fragments of sheet metal, etc.), as well as its subsequent transfer and packaging in a recoverable and advantageously reusable form.

[0013] To do this, and taking into account the type of inputs to be transformed / recovered and their state at the inlet, the technical device carrying out said (at least) first phase of treatment should carry out, progressively and simultaneously, heating of the inputs until reaching a softening / melting temperature of the bituminous binder (at least near the outlet) and shearing of the membranes (pre-cut or not) to result in disintegration of their reinforcements and their disintegration. This device should also allow the passage of the aforementioned hard macroscopic pollutants, without risk of blockage, and preferably have a limited wear rate.

[0014] However, the devices and installations known to date for recycling the aforementioned type of products do not allow us to meet the above demand, nor to achieve the desired result, in any case not in a reliable and sustainable manner.

[0015] Thus, ferromagnetic (magnet) or non-ferromagnetic (eddy current) metal pollutant separators only target one type of pollutant, do not transform or do so insufficiently, and do not allow the extraction of elements that are embedded, nested or too closely linked to the materials to be recovered.

[0016] Similarly, systems based on separation due to differences in densities between components, such as centrifugal systems, densimetric tables, decanting devices or similar, are either inefficient or economically unviable.

[0017] Some known devices satisfactorily perform some of the above-mentioned functions expected for the first phase of treatment, but not all.

[0018] Thus, heated Z-arm kneader type processing devices achieve good shear, but poor heating (batch process), and paddle mixers have satisfactory heating of the products and are robust to pollutants, but achieve poor shear.

[0019] Furthermore, known systems (see in particular WO 2008 / 103035, US 2005 / 263625, EP 1 123 182, EP 0 988 952 , US 4,726,846 and WO 2009 / 090546) in the form of extruders or conventional helical screw conveyors, are subject to blockage in the presence of a hard macroscopic particle (screw, bolt type) and undergo significant and rapid wear in the presence of microscopic hard particles (such as sand). Some of them ( WO 2021 / 104652) are provided with a waste disposal facility once the products have been removed.

[0020] Finally, we also know of twin Archimedean screw mixer conveyors, in which both the screws and the trough are heated: they achieve good heating and good shearing, but are also subject to the blockages and significant wear mentioned above when processing composite products / waste mentioned previously.

[0021] The applicant has already developed a mixer which makes it possible to overcome at least most of the drawbacks of the aforementioned known mixers. This mixer has an elongated construction defining a longitudinal treatment path between at least one inlet and at least one outlet and comprises a trough which is heated and in which is mounted at least one screw, preferably two parallel twin screws which interpenetrate each other at the level of their threads, forming treatment member(s) by dimensional reduction and heating and movement towards said one or more exitsfor the products to be treated introduced at the inlet or each inlet. Said or each screw comprises a support shaft which is heated, rotated about its axis and provided with blades forming the thread of the screw concerned, the or each shaft being arranged in the trough by being arranged according to the direction of travel and the products being moved during treatment from the inlet(s) to the outlet(s) under the action of the screw(s). This mixer is described in PCT patent application WO 2021 / 213793, state of the art according to Article 54(3) EPC, in the name of the applicant and may be part of a treatment installation as disclosed in PCT patent application WO 2021 / 213792 also in the name of the applicant. Mixers of substantially the same type, but nevertheless of different constructions, are known from the document EP 0 231 584 and the document WO 2017 / 194873 .

[0022] However, the inventors were able to verify during tests that it could be interesting, or even necessary in certain operating modes, to be able to regulate the quantity of treated product (output) leaving the mixer, preferably by not significantly complicating the construction of the mixer, by being able, if possible, to guarantee a flow under the effect of gravity alone and without the use of additional means and by providing a solution adapted to the particular nature of the output.

[0023] To meet this demand, the invention, defined by the subject of claim 1, relates to a heating mixer for composite products based on thermoplastic material(s).

[0024] The invention will be better understood from the following description, which relates to a preferred embodiment, given as a non-limiting example, and explained with reference to the appended schematic drawings, in which: [ Fig. 1A ] is an exploded view of a heating mixer of the type covered by the invention, but without a member for controlling the outlet flow of treated product; [ Fig. 1B ] is a perspective and top view of a heating mixer according to the Figure 1A , the trough closing cover being removed; [ Fig. 2A ] is a sectional view along a vertical plane containing the longitudinal axis of the mixer of the Figure 1B ; [ Fig. 2B ] is an elevation view along the direction of the longitudinal axis and partially transparent of the mixer shown Figure 1B ; [ Fig. 3 ] is a top view of the two screws forming part of the mixer of the figures 1 And 2 ; [ Fig. 4 ] is a sectional view along A - A of the mixer of the Figure 1B ; [ Fig. 5 ] is a partial perspective view of the mixer of the figure 4 ; [ Fig. 6] is a detail view of a scraping structure forming part of the mixer shown Figures 4 and 5 ; [ Fig. 7A ] And [ Fig. 7B ] are side elevation (7A) and sectional (7B) views, along a vertical plane offset from that of the figure (7A ), of a heating mixer according to the invention; [ Fig. 8A ] And [ Fig. 8B ] are partial sectional and perspective views, at the level of the mixer outputs of the figures 7 , in two different directions and with different degrees of opening of the exits; [ Fig. 9 ] is a schematic representation illustrating the control loop regulating the flow leaving the mixer of the figures 7 And 8 , And, [ Fig. 10 ] is a perspective view of a treatment and recovery installation comprising two mixers according to the figures 1 to 9 , mounted in parallel and forming the first treatment stations of this installation.

[0025] THE figures 1 to 8illustrate, at least in part, a heating mixer 1 for composite products based on thermoplastic material(s), in particular factory or construction site waste mainly containing bituminous membranes.

[0026] Said mixer 1 has an elongated constitution defining a longitudinal treatment path between at least one inlet 2 and at least one outlet 2' and comprising a trough 3 which is heated and in which is mounted at least one screw 4, 4', preferably two twin screws 4 and 4' parallel and mutually interpenetrating at the level of their threads 4", forming member(s) for treatment by dimensional reduction and heating and for movement towards said one or more exit(s)2' for the products to be treated introduced at the level of the inlet 2 or each inlet 2. Said or each screw 4, 4' comprises a support shaft 5 which is heated, driven in rotation around its axis and provided with blades 9, 9' forming the thread 4" of the screw 4, 4' concerned, the or each shaft 5 being arranged in the trough 3 by being arranged according to the direction of travel DT and the products being moved during treatment from the inlet(s) 2 to the level of the outlet(s) 2' under the action of the screw(s) 4, 4'.

[0027] The trough 3 and the shaft 5 may be heated by a liquid fluid or comprise added heating means, in particular electrical. The or each outlet is preferably located in a lower region of the trough 3 into which the output can be conveyed by the movement action of the screw(s) 4, 4'.

[0028] In accordance with the invention, and as shown in the figures 7 to 9, this mixer 1 is characterized in that the opening of the or each outlet 2' is formed directly in the wall 3' of the trough 3, in that said mixer 1 comprises, at the or each outlet 2', a member 20 for controlling the flow of liquid or semi-liquid output of treated products, flowing through the associated outlet 2', in that the or each member 20 for controlling the flow of output consists of a flap valve or pivoting flap, in that said flap or flap consists of a portion 3" of the wall 3' of the trough 3 swept by blades 9, 9', this portion 3" being able to be moved, preferably continuously, between a closed position in which it closes the outlet 2' considered and is integrated into said wall 3' as a constituent part of the latter, preferably with continuous surface connection with the internal face of this wall,and a maximum opening position in which the corresponding outlet 2' is substantially fully open.,

[0029] Thanks to these provisions, the invention meets the previously expressed request, by providing a simple and efficient solution, adapted to the nature of the output, and substantially in accordance with the preferential requests also mentioned above. Because the region of the trough 3 having the outlet(s) 2' is swept by the or at least one of the screws, any accumulation of output in this region is prevented when the corresponding valve 20 is in the closed state. This avoids the formation of an arch or thickness of output which could slow down or even block the flow of output when the valve in question is opened.

[0030] According to the invention, the or each member 20 proposed is thus of the progressive passage opening type and can be controlled, independently, either for delivery of output in continuous mode (the flow rate of material evacuated then being determined directly and solely by the degree of opening), or for delivery of output in sequential mode or in successive batches (intermittent opening, the flow rate being fixed both by the degree of opening and the opening time).

[0031] When the mixer 1 has two openings 2' and two members 20, the latter can be controlled either separately and independently, or in a common and synchronous manner, or in one or the other manner depending on the wishes of the operator or the requirements of the overall treatment process.

[0032] Advantageously, the trough 3 comprises a double-walled wall 3' and the shaft 5 is a hollow tube, both of which are traversed by a hot fluid (oil). The wall 3' may alternatively also be single-skinned and comprise channels 3‴ for circulating hot fluid on the outside. The or each 3" valve advantageously has a single-walled structure (for example, a curved metal plate), possibly thermally insulated.

[0033] As shown by the figures 4, 5 And 8 in particular, the wall 3' of the trough 3 has, in the lower part forming the bottom of the trough, a curved conformation (partially cylindrical) matching the shape of the or each screw 4, 4' over a part of its or their circumference. It is in this or these bottom region(s) of the wall 3' that the outlet(s) 2' are preferably located, the or each valve having a shape integrating continuously into the corresponding bottom region.

[0034] According to a possible practical construction of the invention, illustrated in the figures 8 and combining simplicity, robustness and control precision, the or each valve 20 with pivoting flap comprises, in addition to the flap 3" forming a movable portion of the wall 3' of the trough 3, an actuator in the form of a motorized rack device 21, determining the pivoting positioning of the flap 3" considered, and therefore the open / closed state of the corresponding outlet. This motorized device 21 is advantageously in the form of a driven pinion 21' meshing with a rack 21" in an arc of a circle secured to said flap 3", preferably carrying the latter. The position of the or each flap 3" can be determined very precisely by a position encoder or by a sensor (at the pivot axis of the flap 3" or the motorized pinion 21').

[0035] In accordance with a simple practical construction illustrated on the figures 8, it may be provided, in a combined manner, that the opening of the or each outlet 2' is formed in a curved portion of the wall 3' of the trough 3, that the valve 3" considered, which constitutes a movable portion of said wall 3' capable and intended to seal this opening in relation to the output, has an inner face with a curved surface of radius identical to that of the surrounding curved region of the inner face of the wall 3' around the outlet opening concerned and that the axis AP of the pivoting connection of said valve 3" with said wall 3' is parallel to the axis of rotation of the or each of the shaft(s) 5.

[0036] According to a characteristic of the invention, arising from the figure 9, the or each member or valve 20 for controlling the output flow E flowing through the associated outlet 2' is controlled by an automatic regulation device 22 associated or integrated into a system for controlling the operation of the mixer 1, where appropriate in relation to a program for controlling the operating mode of said mixer 1, this device 22 evaluating at least signals indicative of the quantity of products present in this mixer 1 and controlling the position or state of the member 20 accordingly, for example by means of the aforementioned motorized rack device 21.

[0037] Preferentially and as symbolically shown by the figure 9 and partially the figures 7, the automatic regulation device 22 is part of a loop 22' for controlling the output flow of said mixer 1. The signals indicative of the quantity of products present in the mixer 1 can be provided by at least one means 23 for weighing said mixer 1, for example a pair of scales. The loop 22' can itself be part of or depend on a control system of a treatment installation 14 in which said mixer 1 is integrated.

[0038] As shown by the figures 8and in order to be able, for example, to direct the output flow towards a subsequent treatment station (avoiding dispersions), the trough 3 may comprise, at the level of the or each outlet 2' and in the outward extension of the opening of the latter, in the form of a rectangular opening in the wall of the trough 3, an end piece 24 forming an evacuation channel. This end piece 24 also advantageously provides a surface 24' for preferred flow of the output, adjacent to the opening of the outlet 2' concerned and with which the valve 3" cooperates during its opening movement to define an evacuation passage with variable section.

[0039] In accordance with a preferred practical construction, promoting precise progressive opening of the outlet 2' concerned, the free end of the pivoting valve 3" sweeps the preferred flow surface 24' over a part of its pivoting movement, at least at the start of the clearance of the opening of the outlet 2', said valve 3" advantageously constituting a part of the discharge channel 24 in its maximum open position. Such a configuration of the valve 3" and of the surface 24' allows in particular self-regulation of the output flow rate E for a given viscosity.

[0040] Although not shown, the heating mixer 1 according to the invention may comprise only one screw, and therefore only one outlet and only one output flow control member.

[0041] However, preferably and as is apparent from the attached figures, the mixer according to the invention comprises two twinned parallel screws 4 and 4', each screw 4, 4' being associated with a respective outlet 2' provided with a corresponding member 20 for controlling the flow of output discharged through the outlet 2' concerned.

[0042] As shown by the figures 1 to 3 And 7B , the thread 4" of the or each screw 4, 4' is an interrupted or discontinuous thread and comprises, over at least a major part of the length of the screw 4, 4' considered, a plurality of first blades 6 in the form of flat and smooth plates, separated from each other axially and radially and all arranged according to a constant screw pitch and with a determined inclination relative to a plane perpendicular to the axis AV of the screw 4, 4' considered.

[0043] The helical thread 4"" of each of the two screws 4 and 4', which rotate in mutually opposite directions of rotation so as to generate a material transport movement from the inlet 2 to the outlet 2' of the trough 3 (in the direction DT), is therefore constituted by a plurality of blades 6 in the form of flat, distinct and separate ring sectors, secured (by welding for example) to the shaft 5 of the screw 4, 4' concerned along a helical line. In addition, these blades 6 are arranged with a mutual spacing and an individual angular extension such that longitudinal alignments 7 of blades 6 are constituted.

[0044] Preferably, each first blade 6 has an angular extension around the shaft in question which is less than 180°, advantageously less than 120°, preferably approximately 90°. In addition, said first blades 6 are configured and arranged on the support shaft 5 in question so as to constitute a limited number of alignments 7 of blades 6 in the direction of the axis AV of the screw 4, 4', which are distributed around the periphery of the support shaft 5 and which define between them clear zones 8 extending along the screw 4, 4' between neighboring alignments 7.

[0045] Thus each of the screws 4, 4' appears substantially, at least over part of its length, like an Archimedes screw with a continuous helical thread, but cut in the direction of the AV axis of the shaft 5 to form rectilinear holes parallel to said AV axis.

[0046] It is the spacing between the blades 6, and more particularly the resulting hole-shaped passages, which allow the transport without blockage of macroscopic pollutants (present in the products to be treated forming inputs) from the inlet 2 to the outlet 2'.

[0047] In addition, the metal blades 6 are relatively thick (for example 8 to 15 mm) so as to guarantee a certain thermal inertia to heat the bitumen in the mass, while grabbing and "loosening" the inputs in the form of membranes. ("Hot knife in cold butter" effect). In addition, by being flat and smooth, the blades 6 do not offer any grip to the bituminous binder or other.

[0048] In accordance with a preferred embodiment, illustrated in the figures 1 , 2 , 4 , 5 And 7B, it is provided that the or each screw 4, 4' comprises, over at least part of its length, a plurality of second blades 9 in the form of flat plates, separated from each other and all arranged in planes perpendicular to the axis of the screw 4, 4' considered, that each second blade 9 has an angular extension of less than 180°, advantageously less than 120°, preferably approximately 90°, and that said second blades 9 are configured and arranged on the support shaft 5 concerned so as to constitute a limited number of alignments 7' of blades in the direction of the axis AV of the screw 4, 4' and around the shaft 5, clear zones extending between the neighboring alignments 7' (angularly or circumferentially) along the screw 4, 4'.

[0049] While the first blades 6 are mounted on the respective shaft 5 with an inclination relative to a plane perpendicular to the AV axis of said shaft, the second blades 9 are shown perpendicular to this AV axis.

[0050] Advantageously, each alignment 7' of second blades 9 extends only over a fraction of the length of the part of the screw 4, 4' comprising them and over a fraction of the periphery of the shaft 5 of the latter and constitutes at least one local group of second blades 9, each group being offset angularly and / or axially relative to each of the other groups and at least one, preferably each, group of second blades 9 of a screw 4, 4' coming into interpenetrating engagement, in an interstitial manner, with a corresponding group of second blades 9 of the other screw 4', 4.

[0051] Additionally or alternatively, the trough 3 may comprise, on at least part of its internal face, located opposite the longitudinal part(s) of the screw 4, 4' comprising second blades 9, fixed counter-blades, located in planes parallel and interstitial with respect to the planes of the second blades 9 and coming into interpenetrating engagement with the second blades 9 during the rotation of the screw 4, 4' considered, each cooperating arrangement of at least two groups of second movable blades 9 belonging respectively to one of the two screws 4, 4', and possibly fixed counter-blades, constituting a privileged shear module 11.

[0052] Thus, the second blades 9 of the screws 4, 4' are not only interfering and interpenetrating between the two screws 4 and 4', but also with fixed counter-blades installed in the trough 3, for example on a support structure mounted interchangeably in the trough 3 (not shown).

[0053] The zones of the mixer 1 comprising groups of pluralities of second movable blades 9, and possibly fixed counter-blades, constitute, due to the density of interpenetrating blade-forming elements with small air gaps, intense shear modules. The mixer 1 may comprise one or more such module(s), where appropriate distributed along the trough 3. Preferably, a (last) shear module is arranged near the outlet of the mixer 1.

[0054] The provision of a distribution of the second blades 9 by alignments 7' spaced circumferentially and / or axially allows solid macroscopic pollutants to pass through the zones of these modules without blocking the screws 4, 4'.

[0055] As illustrated by the following examples: Figures 2A , 3 And 7B, the or each screw is advantageously made up of differentiated longitudinal segments comprising alternately alignments of first inclined blades 6 and alignments of second perpendicular blades 9.

[0056] In order to limit the wear of the first and / or second blades 6, 9 (by providing a sufficient air gap between their outer edges and the wall of the trough 3), while promoting, on the one hand, the heat transfer between the screws 4, 4' and / or the trough 3 and the products to be treated in transit and, on the other hand, the shear

[0057] (despite the presence of a large air gap - for example 0.5 mm to 3 to 5 cm - between blades 6, 9 and trough 3), it may be provided that at least certain first and / or second blades 6, 9 are provided, at their outer free edge 9', with at least one added scraping structure 12, projecting radially relative to said edge 9' and elastically deformable at least in a radial direction, this or these scraping structures 12 sweeping, advantageously with sliding support under elastic pressure, at least a part of the internal face of the wall 3' of the trough 3 (see figures 4 to 6 And 8 ).

[0058] As shown by the figures 8, at least one scraping structure 12 (preferably several mounted on the ends of blades 6, 9 of the screws) is present at the level of the or each portion 3" of the wall 3' of the trough 3 forming a valve, the internal surface of this portion 3" being swept by this structure at each rotation of the screw 4, 4' concerned. Thus, the 3" valves are guaranteed to be free from any accumulation of material which could block their operation and this makes it possible to keep the internal face of the wall 3' clean and free of any agglomeration of components of the output (fibers, minerals, bitumen, etc.), likely to hinder the flow of output at opening (in particular during partial opening) and / or the handling of the valve.

[0059] In accordance with a preferred embodiment, emerging from the figures 4 to 6and 8 above, the or each deformable added structure 12 consists of a plate 12', or a stack of at least two plates 12', with a substantially elliptical contour and comprising cutouts defining a plurality of concentric elliptical rings 13, connected by bridges of material 13' between adjacent rings 13, said structure 12 being mounted on the corresponding blade 6, 9 with an orientation such that the direction of the small half-axis of the elliptical contour passes through the longitudinal axis AV of the support shaft 5.

[0060] Said mixer 1 advantageously comprises two twinned parallel screws 4 and 4' whose respective blades 6, 9 intersect intimately over at least part of their height, preferably a majority part, either in at least one zone of mutual meshing of opposite threads of first blades 6 inclined relative to the axis of the support shaft 5, or in at least one zone of mutual interpenetration of second blades 9 perpendicular to the axis of the support shaft 5, advantageously in both types of zones.

[0061] The invention also has as its object, as shown for example by the figure 10 , an installation 14 for the treatment and recovery of thermoplastic-based composite products, for example waste mainly incorporating bituminous products, in particular bituminous membranes, where appropriate pre-cut or fragmented.

[0062] This installation 14 is characterized in that it comprises, as treatment station(s), at least one mixer 1 as described previously, preferably as the first treatment station.

[0063] As depicted figure 10 , the installation 14 may comprise two heating mixers 1 as described above, mounted in parallel, supplied with inputs by a conveyor belt 15 (transporting for example pre-cut waste) and each forming the first station of a treatment and recovery route, respectively associated downstream.

[0064] This installation comprises for example two heating mixers 1, mounted in parallel, supplied with inputs by a conveyor belt 15 and each forming the first station of a treatment and revalorization path, respectively associated downstream. These mixers 1 are installed at height in such a way that their liquid or semi-liquid outputs, evacuated by the openings of the outlets 2', fall through two superimposed grinding stations 16, each formed by a mill with opposite rollers and whose air gaps are aligned. Between the two grinding stations 16 is arranged a device for separating solid macroscopic pollutants in the form of a rejection device, with a movable extractor member, for example by pivoting not visible on the figure 10 .

[0065] Then, the extract purified of macroscopic pollutants can be transferred (for example by a delicer pump 17) into a refiner 18 with a drum mounted eccentrically in a cylindrical enclosure, to then be stored in a tank 19, in the form of a reusable recovered product.

[0066] Such an installation is described and represented in the patent application mentioned above in the introduction.

[0067] The invention also relates to a method for controlling a mixer 1 as described above, characterized in that it consists, either in a continuous operating mode or in a sequential batch operating mode, in driving the screw(s) 4, 4' with a control protocol comprising at least two drive phases causing a movement of the materials in the mixer 1 in the direction DT of the treatment path, separated by at least one reverse drive phase, i.e. causing a movement of the treated materials in the direction opposite to the treatment path, the occurrence, duration and number of the reverse drive phases being either predetermined or depending on values ​​provided by sensors for measuring operating parameters, such as for example the drive torque, the composition and / or quality of the treated products, the quantity of materials present in the mixer 1.

[0068] Of course, the invention is not limited to the embodiment described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention, which is defined by the claims.

Claims

1. Heatable mixer (1) for the treatment of composite products based on thermoplastic material(s), in particular factory or site waste containing mostly bituminous membranes, said mixer (1) having an elongate composition defining a longitudinal treatment path between at least one inlet (2) and at least one outlet (2'), and comprising a trough (3) which is heated, and in which there is fitted at least one screw (4, 4'), and preferably two twin screws (4 and 4') which are parallel and interpenetrate at their threads (4"), forming a unit / units for treatment by dimensional reduction and heating, and displacement towards said outlet(s) (2') for the products to be treated introduced at the (2) or each (2) inlet, said or each screw (4, 4') comprising a support shaft (5) which is heated, and rotated around its axis, the or each shaft (5) being positioned in the trough (3) by being arranged in the direction of the path (DT), and the products being displaced during the treatment from the inlet (s) (2) as far as the outlet (s) (2') under the action of the screw(s) (4, 4'), and said mixer (1) comprising, at the or each outlet (2'), a unit (20) to control the flow of liquid or semi-liquid output of products treated, flowing through the associated outlet (2'), said heatable mixer (1) being characterized in that the support shaft (5) is provided with blades (9, 9') forming the thread (4") of the screw (4, 4') concerned, in that the opening of the or each outlet (2') is formed directly in the wall (3') of the trough (3), in that the or each unit (20) to control the flow of output consists of a flap valve or pivoting valve, and in that said flap valve or pivoting valve consists of a portion (3") of the wall (3') of the trough (3) which is swept by blades (9, 9'), this portion (3") being able to be displaced, preferably continuously, between i) a closure position in which it closes the outlet (2') concerned, and is incorporated in said wall (3') as a component part thereof, preferably with continuous surface connection with the inner face of this wall, and ii) a maximal opening position in which the corresponding outlet (2') is substantially totally open.

2. Heatable mixer according to Claim 1, characterized in that the or each pivoting flap valve (20) comprises, in addition to the flap valve (3") which forms a movable portion of the wall (3') of the trough (3), an actuator in the form of a motorized device (21) with a rack, which determines the positioning in pivoting of the flap valve (3") concerned, and thus the state of opening / closure of the corresponding outlet (2'), this device (21) advantageously being in the form of a driven pinion (21') which engages with a rack (21") in the form of an arc of a circle integral with said flap valve (3").

3. Heatable mixer according to either of Claims 1 and 2, characterized in that the opening of the or each outlet (2') is formed in a curved portion of the wall (3') of the trough (3), in that the flap valve (3") concerned, which constitutes a movable portion of said wall (3') which can, and is designed to, close this opening in a sealed manner against the output, has an inner face having a curved surface with a radius identical to that of the surrounding curved region of the inner face of the wall (3') around the outlet opening concerned, and in that the axis (AP) of connection with pivoting of said flap valve (3") with said wall (3') is parallel to the axis of rotation of the or each shaft (5).

4. Heatable mixer according to any one of Claims 1 to 3, characterized in that the or each pivoting flap valve (20) is controlled by an automatic control device (22) associated with, or incorporated in, a system to control the operation of the mixer (1), if applicable in relation with a program to control the operating mode of said mixer (1), this device (22) evaluating at least signals which are indicative of the quantity of products present in this mixer (1), and controlling the position or state of the unit (20) accordingly, for example by means of a motorized device (21) with a rack, thus determining the positioning in pivoting of the flap valve (3") concerned.

5. Heatable mixer according to Claim 4, characterized in that the automatic control device (22) forms part of a loop to control the flow of output from said mixer (1), and in that the signals which indicate the quantity of products present in the mixer (1) are provided by at least one weighing means (23) of said mixer (1), for example a pair of weighing cells.

6. Heatable mixer according to any one of Claims 2 to 5, characterized in that, at the or each outlet (2') and in the extension to the exterior of the opening thereof, in the form of a rectangular opening in the wall (3') of the trough (3), the trough (3) comprises a joining piece (24) forming a discharge channel, this joining piece (24) providing a preferential flow surface (24') for the output, adjoining the opening of the outlet (2') concerned, and with which the flap valve (3") cooperates during its opening movement in order to define a discharge passage with a variable cross-section.

7. Heatable mixer according to Claim 6, characterized in that the free end of the pivoting flap valve (3") sweeps the preferential flow surface (24') over a part of its pivoting movement, at least at the start of the clearing of the opening of the outlet (2'), said flap valve (3") advantageously constituting part of the discharge channel (24) in its maximal opening position.

8. Heatable mixer according to any one of Claims 1 to 7, characterized in that the thread (4") of the or each screw (4, 4') is an interrupted or discontinuous thread, and comprises, over at least most of the length of the screw (4, 4') concerned, a plurality of first blades (6) in the form of smooth flat plates, separated from one another axially and radially, and all arranged according to a constant screw pitch, and with a determined inclination relative to a plane perpendicular to the axis (AV) of the screw (4, 4') concerned, in that the or each screw (4, 4') comprises, on at least part of its length, a plurality of second blades (9) in the form of flat plates, which are separated from one another, and are all arranged on planes perpendicular to the axis of the screw (4, 4') concerned, and in that said second blades (9) are configured and arranged on the support shaft (5) concerned such as to constitute a limited number of alignments (7') of blades in the direction of the axis (AV) of the screw (4, 4') and around the shaft (5), with cleared areas extending between the adjacent alignments (7') along the screw (4, 4').

9. Mixer according to any one of Claims 1 to 8, characterized in that at least some first and / or second blades (6, 9) are provided, at their outer free edge (9'), with at least one added-on scraping structure (12), which projects radially relative to said edge (9'), and is resiliently deformable at least in a radial direction, with this scraping structure or these scraping structures (12) sweeping, advantageously with sliding support under resilient pressure, at least part of the inner face of the wall (3') of the trough (3).

10. Mixer according to Claims 2 and 9, characterized in that at least one scraping structure (12) is present at the or each portion (3") of the wall (3') of the trough (3) forming a flap valve, with the inner surface of this portion (3") being swept by this structure at each rotation of the screw (4, 4') concerned.

11. Mixer according to any one of Claims 1 to 10, characterized in that it comprises two parallel twin screws (4 and 4'), the respective blades (6, 9) of which interweave closely on at least part of their height, preferably on most of it, either in at least an area of mutual engagement of the opposing threads of first blades (6) which are inclined relative to the axis of the support shaft (5), or in at least one area of mutual interpenetration of second blades (9) perpendicular to the axis of the support shaft (5), advantageously in both types of areas, each screw (4, 4') being associated with a respective outlet (2') provided with a corresponding unit (20) to control the output flow discharged through the outlet (2') concerned.

12. Installation (14) for treatment and upgrading of composite products based on thermoplastic, for example waste which includes mostly bituminous products, in particular bituminous membranes which if applicable are precut or fragmented, characterized in that it comprises as a treatment station / treatment stations at least one mixer (1) according to any one of Claims 1 to 11, preferably as the first treatment station.

13. Installation for treatment and upgrading according to Claim 12, characterized in that it comprises two heatable mixers (1), fitted in parallel, supplied with inputs by a conveyor belt (15), and each forming the first station of a treatment and upgrading line, respectively associated downstream, in that these mixers (1) are installed at a height such that their liquid or semi-liquid outputs, discharged by the openings of the outlets (2'), fall through two superimposed crushing stations (16), each formed by a crusher with opposing rollers, and the air gaps of which are aligned, and in that, between the two crushing stations (16), a solid macroscopic pollutants separator device is arranged, in the form of a discharge device, with a unit for movable extraction, for example by pivoting.

14. Method for controlling a mixer (1) according to any one of Claims 1 to 11, characterized in that it consists, either in a continuous operation mode, or in a mode of sequential operation in batches, of driving the screw(s) (4, 4') with a control protocol comprising at least two driving phases giving rise to displacement of the materials in the mixer (1) in the direction (DT) of the treatment path, separated by at least one opposing driving phase, i.e. giving rise to displacement of the treated materials in the direction opposite the treatment path, with the occurrence, duration and number of the opposing driving phases being either predetermined, or dependent on values provided by sensors for measurement of operating parameters, such as, for example, the driving torque, the composition and / or the quality of the products treated, and the quantity of materials present in the mixer (1).