CA2147425A1 - Device to mix liquid substances with particles having different granule sizes and relative mixing method - Google Patents

Abstract

Device to mix liquids with particles having different granule sizes, which comprises a mixing chamber (13) and includes a feeder inlet (11), a main outlet (14), injectors (15) to inject an adhesive mixture and possible agitation elements (18), the mixing chamber (13) cooperating with rotary feeder thrust means (12-112) and including also at least one screening extractor outlet (20) associated with riddle means (30) to screen the granule size of particles, the at least one screening extractor outlet (20) covering a zone which runs from the beginning of the feeder inlet (11) of the mixing chamber (13) to the vicinity of the first upstream injector (15) injecting the adhesive mixture, the screening extractor outlet (20) affecting the perimetric periphery of the mixing chamber (13) about at least 5% of the perimeter of the mixing chamber (13), the screening extractor outlet (20) cooperating with at least one channel (24) to convey the fine particles thus separated, and a relative method to mix in the mixing chamber (13) liquids with particles having different granule sizes, these particles introduced into the mixing chamber (13) by the feeder inlet (11) being centrifuged while they are fed forwards in the form of a rotary ring, this rotary ring cooperating with at least riddle or sieve means (30) which select the fine particles and are positioned on the periphery of the mixing chamber (13) upstream of the injection of the adhesive mixture, the particles which do not pass through the riddle or sieve means (30) being fed forwards in cooperation with the adhesive mixture, whereas the fine particles which pass through the riddle or sieve means (30) are fed into a conveyor channel (24).

Description

, 1"DEVICE TO MIX LIQUID SUBSTANCES WITH PARTICLES

3METHOD"
4This invention concerns a device to mix liquid substances with particles having different granule sizes, as set forth 6 in the main claim.
7 This invention concerns also the mixing method carried out 8 with the device according to the invention.
9 The device is applied to mixing machines, namely machines which mix liquid substances, such as adhesive mixtures for 11 instance, with materials that do not combine with each 12 other, whether those materials be fine, granular, fibrous, 13 chips or other materials.
14 To be more exact, this device is correctly applied to the preparation of pastes of particles, which are in particular 16 but not only based on wood, with adhesive mixtures 17 preferably with an aqueous base of a thermosetting type, for 18 instance.
19 The device has the further purpose of separating, possibly rejecting and delivering particles having a fine granule 21 size to a different subsequent mixing step.
22 Mixing machines of the state of the art include a mixing 23 chamber with a substantially cylindrical configuration, 24 which comprises at one end a main feeder inlet to feed solid material.
26 The solid material is fed by suitable rotary feeder means 27 in the first segment of the mixing chamber towards the 28 opposite end of the mixing chamber, where the main 29 downstream outlet for the mixture produced is provided.
The action of these rotary feeder means causes the solid 31 material to tend to be arranged in the form of a rotary ring 32 against the inner sidewall of the mixing chamber.
33 Within the mixing chamber a shaft rotates that bears a 214742~

_ - 2 -1 plurality of mixing implements, which provide the rotary 2 ring with the suitable centrifugal mixing force and which 3 contribute to the feed of the material at the same time.

4 The axis of the rotary shaft coincides generally with the axis of the mixing chamber, but embodiments can be employed 6 equally well with the axis of the rotary shaft inclined or 7 askew in relation to the axis of the mixing chamber, or else 8 with the rotary shaft parallel to the axis of the mixing 9 chamber but offset laterally or upwards or downwards therefrom.
11 Likewise, mixing chambers can be employed of which the 12 cross-section perpendicular to the lengthwise axis of the 13 mixing chamber has an oval, elliptic, ovoidal, etc. form.
14 Injectors to inject the liquid adhesive products to be mixed with the solid material are included at least along 16 the first segment of the mixing chamber.
17 Agitation elements are advantageously comprised downstream 18 of the injectors or interposed therebetween and are 19 positioned suitably in the interspaces between the mixing implements solidly fixed to the shaft.
21 In such a structure the finest particles of the uncombined 22 solid material, in relation to the rotary feeder means, have 23 a tendency to be arranged on the periphery of the rotary 24 ring, and this tendency is enhanced as soon as these particles are affected by the introduction of the liquid 26 substances by the injectors.
27 This fact entails the result that the distribution of the 28 liquid substances does not takes place evenly in the whole 29 thickness of the ring but takes place in a differentiated manner depending on the granule sizes of the solid material 31 introduced.
32 In particular, the lighter particles having a smaller 33 thickness and greater specific surfaces, owing to physical - _ 3 _ 1 reasons and to their outer arrangement in the rotary ring, 2 are often affected too much by the action of the liquid 3 adhesive substances as compared to the particles having 4 greater dimensions.
It is obvious that an uneven distribution of the liquid 6 adhesive substances on all the particles of solid materials 7 leads to a decrease in the efficiency of the mixer.
8 In particular, such a distribution leads to a non-9 homogeneous product and a high and excessive consumption of adhesive substances.
11 A disclosure has been made for extracting a part of the 12 material to be mixed at a position immediately upstream of 13 the injectors of adhesive material and of reintroducing this 14 material downstream of the injectors, but this disclosure has been found to be not advantageous and does not overcome 16 the problem; moreover, the problem of the incorrect 17 distribution of the adhesive remains substantially unsolved.
18 DE-A-1.528.238 discloses the introduction of products of a 19 given size at the initial part of the mixer and the introduction of the fine particles at the end part.
21 In this disclosure the products of a given size and the 22 fine particles have to be separated upstream of the mixer.
23 According to this document of the prior art the fine 24 particles are introduced through a lengthwise aperture the length of which can be adjusted from the end towards the 26 beginning.
27 Moreover, these fine particles are delivered by a 28 distributor which does not introduce them all at one very 29 exact point.
It is obvious that the more the fine particles are 31 introduced towards the end of the mixing chamber, the less 32 those fine particles can be amalgamated.
33 The present applicants have designed, tested and embodied 21~7425 -1 this invention to overcome this problem and to achieve 2 further advantages.
3 This invention is set forth and characterised in the 4 respective main claims, while the dependent claims describe variants of the idea of the main embodiment.
6 The invention discloses a device which can be employed 7 advantageously, but not only, with solid materials of a 8 particulate type based on wood, and which is suitable to 9 make uniform the distribution of liquid substances, such as a water-based adhesive mixture or the like, on the whole 11 range of the granule sizes of the solid material introduced 12 into the mixing chamber.
13 The device according to the invention also enables an 14 appreciable saving to be achieved in the adhesive mixture introduced into the mixing chamber to produce finished 16 products such as, in particular, panels composed of 17 particles which are advantageously, but not only, based on 18 wood.
19 The invention is applied to mixers of a known type, so that existing mixers too can be converted according to the 21 invention without requiring that these mixers should have 22 special structures. In other words the invention is applied 23 to all the mixing machines which, owing to the centrifugal 24 action determined by the feeder means and rotary implements, are characterised by the formation of a ring of rotating 26 particles within the mixing chamber with a peripheral 27 distribution of the finest particles.
28 This device, taking advantage also of cooperation with 29 suitable thrust implements included in the first segment of the mixing chamber, provides for the extraction by 31 centrifuging of the finest particles which are positioned in 32 the most peripheral layer of the rotating ring.
33 The finest particles are directed by centrifuging, and 2I 47~25 1 also by the action of the thrust implements, at least 2 towards a screening extractor outlet provided in the 3 periphery of the outer wall of the mixing chamber in a 4 position that is not affected by the point of the beginning of the introduction of the adhesive mixture.
6 In this way it is ensured that the extraction involves a 7 great quantity of fine particles which have not been wetted 8 by the liquid adhesive substances.
9 The circumferential position of the screening extractor outlet can be at any perimetric point of the mixing chamber 11 and can cover any perimetric area of that chamber in that 12 zone, and in the description that follows we shall refer, 13 for convenience of illustration alone, to a screening 14 extractor outlet positioned below the mixing chamber.
According to the invention a sieve or riddle containing 16 perforations of the desired size is included in cooperation 17 with the screening extractor outlet for the fine particles 18 so as to ensure a precise and efficient control of the 19 granule size of the fine particles there extracted.
The perforations of the sieve or riddle may be circular, 21 oval, square, rectangular, or lozenge-shaped or may have 22 another desired geometric shape.
23 According to a variant the perforations have a deformation 24 obtained by raising one edge towards the inside of the mixing chamber and possibly by lowering the diametrically 26 opposite edge.
27 According to the invention one embodiment thereof arranges 28 that the part raised towards the inside of the mixing 29 chamber is upstream of the perforation in the direction of feed of the rotating ring.
31 The perforation, where it is circular, preferably has a 32 nominal diameter within the range from 0.2 to 20 mm.
33 According to a preferred embodiment this diameter is _ -- 6 --1 between 1 and 4 mm.
2 Where the perforation has an oval, triangular or square 3 form or another polygonal form, the n~mi n~ 1 diameter is that 4 relating to the circumference which is formed in the hole.
According to one embodiment of the invention the screening 6 extractor outlet for the fine particles has a fixed width 7 and a fixed length.
8 According to a variant the screening extractor outlet has 9 a width can be adjusted as desired.
According to another variant the screening extractor 11 outlet has a length which can be adjusted as desired.
12 The width and/or length of the screening extractor outlet 13 can be adjusted by means of a gate valve that can restrict 14 its span, the gate valve being capable of linear sliding or perimetric sliding along the perpendicular section of the 16 mixing chamber.
17 According to one embodiment of the invention the 18 lengthwise extent of the screening extractor outlet has a 19 great size at least equal to the length of the feeder inlet through which the unseparated granular material is 21 introduced.
22 According to a variant the length and/or width of the 23 screening extractor outlet has a value required for the 24 entry of the desired quantity of fine particles from the mixing chamber.
26 The screening extractor outlet covers always and only the 27 dry zone located upstream of the injectors and begins 28 advantageously in correlation with the beginning of the 29 feeder inlet.
According to a variant an extractor element is comprised 31 in cooperation with the screening extractor outlet and 32 downstream thereof and is suitably inclined in relation to 33 the direction of feed of the solid material and extends _ -- 7 1 within the mixing chamber by a length which can be adjusted 2 as desired. This extractor element cooperates with thrust 3 implements in extraction of the outermost particles of the 4 rotary ring and has the purpose of facilitating the extraction of fine particles which have still not reached 6 the outer part of the rotary ring.
7 According to a variant the inclination of the extractor 8 element in relation to the direction of feed can be 9 adjusted.
According to a further variant the extractor element can 11 also be oriented in relation to a plane perpendicular to the 12 axis of the mixing chamber.
13 The extractor element can be flat or can have a shape like 14 a spoon.
According to one embodiment of the invention the screening 16 extractor outlet is connected to a receiving duct, the end 17 part of which communicates with at least one conveyor 18 channel.
19 In one embodiment of the invention the conveyor channel is connected at its downstream end to a delivery conduit, which 21 communicates with the inside of the mixing chamber through 22 at least one delivery inlet for re-introduction of the fine 23 particles into the mixing chamber.
24 According to a variant the conveyor channel cooperates directly with the delivery inlet in re-introducing the fine 26 particles into the mixing chamber .
27 According to a further variant the conveyor channel 28 cooperates directly with the screening extractor outlet in 29 receiving the fine particles from the mixing chamber; in this case the conveyor channel will have a conformation 31 suitable for the receipt and conveying by means of a 32 suitable lead-in for the flow of particles from the inside 33 of the mixing chamber.

214742~

1 The conveyor channel is equipped with conveyor means to 2 re-introduce the extracted fine particles into the mixing 3 chamber; this re-introduction of the fine particles takes 4 place at any point between the end of the screening extractor outlet and the downstream end of the mixing 6 chamber.
7 The conveyor means can be of a mechanical type, with a 8 piston or worm for instance, or of a pneumatic type 9 employing aspiration or else of a type employing injectors of liquid substances or injectors of air.
11 The delivery conduit is equipped with suitable conveyor 12 means which re-introduce into the mixing chamber the 13 extracted fine particles.
14 This delivery conduit can be positioned in any circumferential position in relation to the mixing chamber.
16 Where the conveyor means operate with aspiration, 17 according to the invention the conveyor channel cooperates 18 either with slide valve means or with a cyclone means.
19 Where the circumferential position of the delivery conduit and its inclination make it possible, the delivery conduit 21 can lack conveyor means to re-introduce the fine particles 22 if this re-introduction can take place by gravity.
23 According to another embodiment of the invention the fine 24 particles are not re-introduced into the mixing chamber but are delivered separately, together with the main flow of 26 material leaving the outlet of the mixing chamber, to a 27 post-mixer or to another different mixing process.
28 The mixing device according to the invention in this case 29 will behave as a means that separates fine materials by centrifuging without requiring any additional equipment.

31 The fine particles engaged by the appropriate means, at 32 the moment of their re-introduction into the mixing chamber 33 through the delivery inlet, are removed by friction by the g 1 rotating mixture. In this way these fine particles are 2 brought to cooperate with the surplus of liquid substance in 3 the mixture, this surplus being generated by the smaller 4 quantity of solid material affected by the liquid along the whole segment in which the fine particles are not within the 6 mixing chamber.
7 According to the invention means to introduce steam, water 8 or another suitable liquid are included in cooperation with 9 and downstream, or only downstream, of the delivery conduit re-introducing the fine particles.
11 Where the fine particles are re-introduced upstream of the 12 last injector of adhesive mixture, these fine particles 13 interact directly with at least a percentage of the mixture 14 introduced by the downstream injectors.
According to the invention the point of re-introduction of 16 the fine particles , however, should not be too near the 17 discharge zone so as to provide for the fine particles a 18 sufficient segment of cooperation with the mixture produced 19 up to that point.
The attached figures are given as a non-restrictive 21 example and show some preferred embodiments of the invention 22 as follows:-23 Fig.1 shows diagrammatically a partly cutaway lengthwise24 view of a first form of embodiment of the mixer according to the invention;
26 Fig.2 shows a cross-section along the line A-A of Fig.1;
27 Fig.3 shows a partly cutaway lengthwise view of a variant of 28 Fig.1:
29 Fig.4 shows a cross-section along the line B-B of Fig.3;
Fig.5 shows a cross-section of the mixer along the line C-C
31 of Fig.3;
32 Fig.6 shows a variant of the mixer of Fig.1;
33 Fig.7 shows partly a variant of Fig.2;

21q7425 1 Fig.8 shows diagrammatically a device to screen particles in 2 association with the mixer according to the invention;
3 Figs. 9a and 9b show two possible conformations of the 4 riddle or sieve means.
A mixer 10 shown in Fig.1 includes a feeder inlet 11 to 6 introduce solid material and rotary feeder means 12 formed 7 as a worm to feed the solid material into a mixing chamber 8 13 and towards an outlet 14 for the mixture produced.
9 According to the variant of Fig.3 the rotary feeder means 12 consist of feeder thrust implements 112 fitted at least 11 on the initial portion of a rotary shaft 16.
12 Aecording to the invention the rotary feeder means 12-112 13 perform also the task of elements to extract the fine 14 particles by centrifuging them towards the sidewall of the mixer 10.
16 According to the invention the feeder thrust implements 17 112 can be adjusted for inclination and for distance in 18 relation to the sidewall of the mixing chamber 13.
19 The mixer 10 includes a plurality of injectors 15 to introduce an adhesive mixture, which are positioned in 21 cooperation with at least the first segment of the mixing 22 chamber 13; these injectors 15 can be of a type using a 23 conduit, a nozzle or pressure or can be of another known 24 type suitable for the purpose.
The rotary shaft 16 is equipped with a plurality of mixing 26 implements 17 suitable to set in rotation the solid material 27 and the liquid substances gradually introduced. The mixing 28 implements 17 can have various forms of the state of the 29 art.
The mixer 10 also includes in this case a plurality of 31 agitation elements 18 positioned downstream of the last of 32 the injectors 15 of the adhesive mixture.
33 According to the invention the agitation elements 18 are - 2147~2S

1 also equipped to introduce into the mixing chamber 13 steam, 2 water or another suitable liquid or gaseous substance at 3 least in the zone of re-introduction of the fine particles 4 or downstream of that zone; this will take place when the water content in the adhesive mixture introduced upstream 6 is, for processing reasons, less than the required quantity 7 of water in the adhesive mixture.
8 The agitation elements 18 are positioned in the 9 interspaces between the mixing implements 17 so as not to create contacts with those implements 17.
11 Upstream of the injectors 15 introducing the adhesive 12 mix~ure, the mixer 10 is equipped with suitable thrust 13 implements 19 borne and set in rotation by the rotary shaft 14 16; these thrust implements 19 cooperate with the rotary feeder thrust means 12-112 acting also as an extractor 16 element and with at least one screening extractor outlet 20 17 provided in the wall of the mixing chamber 13 so as to 18 extract the fine particles of the uncombined mixture of 19 solid material introduced into the mixing chamber 13.
In this case the screening extractor outlet 20 is located 21 in the lower part of the mixer 10, but its position could be 22 at any circumferential point in the wall of the mixer 10 at 23 the angle "~" of Fig.7 which can vary from 0 to 360.
24 The screening extractor outlet 20 is located in the zone which is defined, along the axis of the mixing chamber 12, 26 by the beginning of the feeder inlet 11 and by the first 27 injector 15 of the adhesive mixture.
28 The screening extractor outlet 20 cooperates with a riddle 29 or sieve 30 and begins advantageously in the vicinity of the beginning of the feeder inlet 11.
31 According to the invention the screening extractor outlet 32 20 takes up at least 5% of the periphery of the mixing 33 chamber 13.

- 2147~25 1 In the example shown in Figs.2 and 4 the periphery of the 2 mixing chamber 13 taken up by the screening extractor outlet 3 20 is 50~ of the whole perimeter of the mixing chamber 13;
4 this perimetric zone can extend about the whole perimeter of the mixing chamber 13.
6 The fine particles are positioned by centrifuging in the 7 outermost peripheral layer of the ring of solid material 8 which becomes formed by the thrust action of the rotary 9 feeder thrust means 12-112, mixing implements 17 and thrust implements 19.
11 In this connection at least the rotary feeder thrust means 12 12-112 have at their lower end an elongate conformation 13 suitable for enhancing the centrifugal action (Fig.7).
14 The most downstream position of the screening extractor outlet 20 has as its limit the first of the injectors 15 16 injecting the adhesive mixture, care being taken to include 17 a necessary safety segment between the screening extractor 18 outlet 20 and the first injector 15.
19 In this way the fine particles extracted from the mixing chamber 13 have still not been lapped by the adhesive 21 mixture.
22 A riddle or sieve 30 containing perforations 39 of a 23 desired size and characteristics is included in cooperation 24 with the screening extractor outlet 20; this riddle or sieve 30 has the purpose of selecting the particles passing 26 through and of controlling precisely and accurately their 27 granule size 28 In the embodiment of Figs.l and 3, in which the screening 29 extractor outlet 20 is positioned below the mixer 10, the riddle 30 takes up the lower half-casing of the mixer 10;
31 According to a first embodiment the screening extractor 32 outlet 20 can have a fixed width and length, or else the 33 width or length or both can be adjusted to pre-set the span - 2147~2~

1 of the screening extractor outlet 20 before processing 2 begins or during processing.
3 The width and length of the screening extractor outlet 20 4 can be determined so as to vary the quantity of particles extracted from the mixing chamber 13.
6 The particles extracted pass from the screening extractor 7 outlet 20 into a receiving duct 23 and thence into a 8 conveyor channel 24.
9 The lengthwise axis of the receiving duct 23 coincides advantageously with the axis of positioning of the screening 11 extractor outlet 20.
12 According to a variant the axis of the receiving duct 23 13 forms together with the axis of positioning of the screening 14 extractor outlet 20 an angle which may vary between 0 and +
90, namely the angle "a" in Fig.7, in which the extreme 16 positions represent the case of a receiving duct 23 17 perpendicular and tangential respectively to the mixing 18 chamber 13 19 The conveyor channel 24 is equipped with means 25 to thrust the extracted particles; these thrust means 25 are of 21 a known type and can be mechanical actuation means of a 22 piston or worm type, for instance.
23 According to a variant these thrust means 25 are of a 24 pneumatic type using a negative pressure or air injectors, water or steam injectors or injectors of another liquid or 26 gaseous substance of a low density in order to fluidify the 27 mass of particles and to assist their flow along the 28 conveyor channel 24.
29 These injectors can be placed in only the initial portion of the conveyor channel 24 or can be distributed along the 31 whole length of the conveyor channel 24.
32 These feeder thrust means 25 take the extracted particles 33 to the vicinity of a delivery conduit 26 which comprises a 2147~2~

delivery inlet 27 communicating with the inside of the 2 mixing chamber 13 and located downstream of the screening 3 extractor outlet 20.
4 The delivery conduit 26 too is equipped with thrust means 28 of a known type to re-introduce the particles into the 6 mixing chamber 13.
7 Agitation elements 18 which act also as injectors to 8 inject liquid or gaseous substances required to humidify the 9 fine particles and/or the mixture are included in cooperation with the delivery inlet 27 or immediately 11 upstream or downstream of the same 27.
12 The delivery inlet 27 too can take up any circumferential 13 position in relation to the mixer 10, with the angle "~" in 14 Fig.5, which can vary between 0 and 360.
In this case too the lengthwise axis of the delivery 16 conduit 26 forms together with the axis of positioning of 17 the delivery inlet 27 an angle, the angle "â" of Fig.5, 18 which can vary between 0 and + 90, so as to make possible, 19 depending on the case in question, a re-introduction of the fine particles in a direction perpendicular or tangential to 21 the mixing chamber 13 or in a direction between the 22 perpendicular and the tangential directions.
23 When the fine particles are re-introduced in a 24 perpendicular or substantially perpendicular direction and from above. into the mixing chamber 13, the delivery conduit 26 26 can lack its thrust means 28 inasmuch as the re-27 introduction will take place by gravity.
28 According to the variant shown in Fig.6, the fine 29 particles are not re-introduced into the mixing chamber 13 but, after being separated therefrom, are sent through an 31 outlet 34 to a separate post-mixer (not shown) together with 32 the product leaving the main downstream outlet 14 or else 33 are sent to another separate mixing process.

21~7425 1 According to another variant the invention includes two or 2 more screening extractor outlets 20, each of which is 3 associated with a separate receiving duct 23 and a separate 4 conveyor channel 24 and possibly with different riddles or sieves 30 to select different granules sizes.
6 The fine particles thrust by the thrust means 28 through 7 the delivery inlet 27 towards the inside of the mixing 8 chamber 13 are drawn by friction by the rotating mixture 9 formed up to that point. This mixture is supersaturated since the liquid substances are introduced in quantities 11 sufficient for the whole volume of solid material introduced 12 thr~ugh the main upstream feeder inlet 11.
13 As far as the point of re-introduction of the fine 14 particles there is therefore in the mixture a surplus of liquid, which affects the fine particles only in the segment 16 downstream of their re-introduction into the mixing chamber 17 13.
18 This point of re-introduction of the fine particles, 19 which is the position of the delivery inlet 27, can be at any point between the zone lapped by the injectors 15 of the 21 adhesive mixture and the zone of the main downstream outlet 22 14 of the mixed product.
23 This point of re-introduction, however, should not be too 24 near to the main downstream outlet 14 of the mixed product but should leave a sufficient segment of cooperation between 26 the surplus of liquid substances and the fine particles re-27 introduced into the mixing chamber 13.
28 According to another variant shown in Fig.8 the mixer 10 29 according to the invention can be integrated into a system of separation of the fine particles, this system being 31 located upstream of the mixer 10 itself.
32 This system comprises a silo 31 to store the separated 33 material; this silo 31 feeds by means of a suitable dosing machine 32 the coarser particles directly to the main feeder 2 inlet 11 of the mixer 10, whereas the finer particles are 3 introduced separately by means of a relative dosing machine 4 33 into the mixer 10 downstream of the zone of introduction 5 of the adhesive mixture, which is defined by the injectors 6 15.

7 This system of separation of the fine particles can be an 8 alternative to the system according to the invention or can 9 be complementary thereto, as is shown in Fig.8, in which 10 there are also included the screening extractor outlet 20 11 and the conveyor channel 24 to obtain the separation of the 12 fine particles too within the mixer 10.
13Figs.9a and 9b show two types of deformations 35-36 of the 14 perforations 39 with a nominal diameter 38.
15 Deformations 35 positioned upstream of the perforations 39 16 according to the direction of rotation (shown by the arrow 1737) of the rotary feeder thrust means 12-112 face towards 18 the inside of the mixing chamber 13, whereas deformations 36 19 positioned downstream of the perforations 39 face outwards.

Claims (22)

1 - Device to mix liquids with particles having different granule sizes, which comprises a mixing chamber (13) and includes a feeder inlet (11), a main outlet (14), injectors (15) to inject an adhesive mixture and possible agitation elements (18), the mixing chamber (13) cooperating with rotary feeder thrust means (12-112), the device being characterised in that the mixing chamber (13) includes at least one screening extractor outlet (20) associated with riddle means (30) to screen the granule size of particles, the at least one screening extractor outlet (20) covering a zone which runs from the beginning of the feeder inlet (11) of the mixing chamber (13) to the vicinity of the first upstream injector (15) injecting the adhesive mixture, the screening extractor outlet (20) affecting the perimetric periphery of the mixing chamber (13) about at least 5% of the perimeter of the mixing chamber (13), the screening extractor outlet (20) cooperating with at least one channel (24) to convey the fine particles thus separated.

2 - Device as in Claim 1, in which the conveyor channel (24) cooperates with at least one delivery inlet (27) located in the periphery of the mixing chamber (13) at a position downstream of the screening extractor outlet (20).

3 - Device as in Claim 1, in which the conveyor channel (24) cooperates with an outlet (34) for the differentiated feeding of the fine particles to downstream means.

4 - Device as in Claim 2, in which at least one delivery conduit (26) is included between the delivery inlet (27) and the conveyor channel (24).

5 - Device as in any claim hereinbefore, in which the screening extractor outlet (20) is associated with at least one receiving duct (23).

6 - Device as in any claim hereinbefore, in which the conveyor channel (24) is associated with thrust means (25).

7 - Device as in any claim hereinbefore, in which the screening extractor outlet (20) is positioned at a desired point of the periphery of the mixing chamber (13).

8 - Device as in any claim hereinbefore, in which the delivery inlet (27) is positioned at a desired point of the periphery of the mixing chamber (13).

9 - Device as in any claim hereinbefore, in which the screening extractor outlet (20) cooperates with means which can at least restrict its width.

10 - Device as in any claim hereinbefore, in which the screening extractor outlet (20) cooperates with means which can at least restrict its length.

11 - Device as in any claim hereinbefore, in which the rotary feeder thrust means (12-112) act also as an extractor element in the segment where they cooperate with the screening extractor outlet (20)

12 - Device as in any claim hereinbefore, in which the screening extractor outlet (20) cooperates with at least one auxiliary extractor element extending within the mixing chamber (13).

13 - Device as in any claim hereinbefore, in which the riddle or sieve means (30) include perforations (39) having a nominal diameter (38) between 0.2 and 20 mm.

14 - Device as in any claim hereinbefore, in which the riddle or sieve means (30) include perforations (39) having a nominal diameter (38) between 1 and 4 mm.

15 - Device as in any claim hereinbefore, in which the perforations (39) include at least one deformation (35) facing towards the inside of the mixing chamber (13) and positioned upstream of the perforation (39).

16 - Device as in any claim hereinbefore, in which agitation means (18) having also the function of injectors of liquid or gaseous substances are included in cooperation with the delivery inlet (27).

17 - Device as in any claim hereinbefore, in which agitation means (18) having also the function of injectors of liquid or gaseous substances are included in cooperation with the segment of the mixing chamber (13) running from the delivery inlet (27) to the main downstream outlet (14).

18 - Method to mix liquids with particles having different granule sizes in a mixing chamber (13), which includes a feeder inlet (11), a main outlet (14), means (15) to inject an adhesive mixture and possible agitation elements (18), the-mixing chamber (13) cooperating with rotary feeder thrust means (12-112), the method being characterised in that the particles introduced into the mixing chamber (13) by the feeder inlet (11) are centrifuged while they are fed forwards in the form of a rotary ring, this rotary ring cooperating with at least riddle or sieve means (30) which screen the fine particles and are positioned on the periphery of the mixing chamber (13) upstream of the injection of the adhesive mixture, whereby the particles which do not pass through the riddle or sieve means (30) are fed forwards in cooperation with the adhesive mixture, whereas the fine particles which pass through the riddle or sieve means (30) are fed into a conveyor channel (24).

19 - Method as in Claim 18, in which the fine particles in the conveyor channel (24) are reintroduced into the mixing chamber (13) at a position downstream of the injector means (15) injecting the adhesive mixture.

20 - Method as in Claim 18, in which the fine particles in the conveyor channel (24) are reintroduced into the mixing chamber (13) at a position in cooperation with the last downstream injector means (15) injecting the adhesive mixture.

21 - Method as in any of Claims 18 to 20 inclusive, in which the fine particles are reintroduced into the mixing chamber (13) in the peripheral band covered by the agitation elements (18).

22 - Method as in any of Claims 18 to 21 inclusive, in which the rotary ring, immediately upstream of the perforations (39) of the riddle or sieve means (30), encounters a deformation (35) facing towards the inside of the mixing chamber (13).