Solid residue recovery unit of a decanter in a centrifugal separator

Abstract

Solid residue recovery unit (Q) of a decanter (D) of a centrifugal separator; said solid residue recovery unit (Q) comprising a solid scraper (100) comprising two side arms (2), an arch (3) connected to the two side arms (2) and a plurality of scraping tools (4) protruding externally from the arch (3) and from the side arms (2); the solid scraper (100) is driven by a driving assembly 5 (5) comprising a rotating shaft (51), a rotating means (50) that rotates the rotating shaft (51) around its longitudinal axis (X), a connection body (52) that is rotatably integral with the rotating shaft (51) and rotatably and eccentrically connects a central section (30) of the arch (3) to the rotating shaft (51), integral coupling means (531, 532) that rotatably and integrally couple the connection 10 body (52) to the rotating shaft (51), and rotatable coupling means (54) that rotatably connect the central section (30) of the arch (3) to the connection body (52).

Description

[0001] SOLID RESIDUE RECOVERY UNIT OF A DECANTER IN A CENTRIFUGAL SEPARATOR

[0002] DESCRIPTION

[0003] The present patent application for industrial invention relates to a solid residue recovery unit for a decanter in a centrifugal separator.

[0004] As it is known, centrifugal separation mechanisms are used in the separation technology of products with different densities.

[0005] By way of example, the centrifugal separation technology is used in the production of olive oil, where the main components of the fruit are separated at the end of the process into a valuable liquid component (oil), a waste liquid component (water), and solid residues commonly referred to as “pomace.” In spite of being considered as waste, the solid component can be recycled and used as fuel in biomass boilers or to feed anaerobic fermentation processes for the production of gas or fertilizers.

[0006] In addition to the oil sector, centrifugal separators are also used in other food and industrial sectors, for example, for the processing of industrial sludge, slop oil and food in general, where it is necessary to separate components of different densities.

[0007] More specifically, the extraction processes are based on the use of machines called centrifugal separators / extractors or decanters that are suitable for separating the valuable liquid component, the waste liquid component, and the solid residues.

[0008] Fig. 1 Prior Art illustrates a conventional decanter, which is generally indicated with the reference letter D.

[0009] A conventional decanter (D) comprises:

[0010] - a fixed frame (F);

[0011] - a rotating drum (T) rotatably mounted on the fixed frame (F) and comprising a cylindrical section (T1 ) and a conical section (T2);

[0012] - a screw conveyor (C) rotatably inserted inside the rotating drum (T) with the same direction as the rotating drum (T), but at a different speed; the screw conveyor (C) has a longitudinal channel (not shown in the appended figures) wherein the product to be separated is fed, and holes from which the product to be separated is ejected and poured into the rotating drum (T).

[0013] Due to the different rotational speed of the rotating drum (T) and of the screw conveyor (C), the various components of the product with different specific weight are separated and stratified inside the rotating drum (T).

[0014] In fact, the solid residues (s) of the product tends to move towards the conical section (T2) of the rotating drum (T), whereas the liquid component (q) tends to move in the opposite direction towards the cylindrical section (T1 ) of the rotating drum.

[0015] An ejection outlet (T10) is provided at the end of the cylindrical section (T1 ), whereas an ejection flange (G) with perimeter holes (G1 ) for the ejection of the solid residues (s) is provided at the end of the conical section (T2) of the rotating drum (T).

[0016] With reference to Fig. 2 Prior Art, such an ejection flange (G) is located inside a collection chamber (10) defined by a box body (1 ) comprising:

[0017] - a first rear edge (1 1 ) having a hole wherein said conical section (T2) of the rotating drum (T) is rotatably and thoroughly inserted in such a way that the ejection flange (G) is positioned inside the collection chamber (10);

[0018] - a second front edge (12) parallel to the first edge (1 1 );

[0019] - a side wall (13) comprising two vertical sections (131 ) parallel to each other and a curvilinear upper section (132) connecting the two vertical sections (131 ) and extending for an arc of circumference of 180°; the curvilinear upper section (132) comprises a vertex (132a) and two lateral sides (132b);

[0020] - a lower discharge outlet (14).

[0021] During the rotation of the rotating drum (T) rotates, jets of solid residues (s) are ejected from the holes (G1 ) of the ejection flange (G) by centrifugal force and are moved in radial directions with respect to the ejection flange (G).

[0022] Therefore, part of the solid residues (s) is thrown directly towards the lower discharge outlet (14), whereas another part of the solid residues (s) is thrown towards the side wall (13) of the box body (1 ) and is adhered to it. In order to recover the solid residues (s) that are adhered to the inner surface of the side wall (13) of the box body (1 ), solid scraping devices have been designed to scrape the inner surface of the side wall (13) of the box body (1 ) so as to detach the solid residues from the inner surface and cause them to fall towards the lower discharge outlet (14).

[0023] Figs. 3, 3A, and 3B Prior Art schematically illustrate a conventional solid scraper (900) that is currently available on the market.

[0024] The solid scraper (900) comprises an articulated quadrilateral (910) comprising an upper crossbar (911 ) disposed under the through hole wherein the truncated-conical section (T2) of the rotating drum (T) is rotatably inserted, a lower crossbar (921 ) parallel to the upper crossbar (911 ), two side arms (931 ) running parallel to the two vertical sections (131 ) of the side wall (13) of the box body (1 ), upper pivoting pins (P91 ) that hinge the ends of the upper crossbar (91 1 ) to central portions of the two side arms (931 ), and lower pivoting pins (P92) that hinge the ends of the lower crossbar (921 ) to the lower ends of the two side arms (931 ).

[0025] Moreover, the solid scraper (900) comprises an arch (902) having two terminal ends hinged to two upper ends of the two side arms (931 ) by means of pivoting pins (P93).

[0026] The solid scraper (900) also comprises a plurality of tools (904), such as scrapers or spatulas, which protrude outwardly from the arch (902) and from the side arms (931 ).

[0027] A rotating means, namely a motor, is connected to the center of the upper crossbar (91 1 ) to rotate the upper crossbar (91 1 ) around an axis orthogonal to the plane whereon the solid scraper (900) lies, that is to say around an axis parallel to the longitudinal axis of the rotating drum (T).

[0028] In particular, the upper crossbar (91 1 ) is rotated in a first direction (V1 ) (shown in Fig. 3A) and in a second direction (V2) (shown in Fig. 3B) so that each time the upper crossbar (91 1 ) is positioned with a maximum inclination of approximately +20° or -20° with respect to a horizontal plane. Otherwise said, the upper crossbar (91 1 ) basically oscillates continuously with an oscillation angle of approximately 40°. The oscillation of the upper crossbar (91 1 ) causes the motion of the articulated quadrilateral (901 ), and consequently the lifting of one arm (931 ) and the simultaneous lowering of the other arm (931 ) and vice versa. As a result, the arch (902) is simultaneously pushed by one arm (931 ) and pulled by the other arm (931 ), thus causing an inclination of the arch (902), with consequent scraping of the inner surface of the side wall (13) of the box body (1 ) by means of said tools (904).

[0029] In spite of being widely used, such a solid scraper (900) of the prior art is not effective; in fact, the arch (902) performs a movement that does not allow the tools (904) to scrape the side wall (13) of the box body (1 ) properly. As a result, a large quantity of solid residues (s) remains adhered to the side wall (13).

[0030] Furthermore, it should be noted that such a type of solid scraper (900) needs a motor with reverse rotation or special transmission means to convert the one-direction rotary motion of the motor into an oscillatory motion of the upper crossbar (91 1 ).

[0031] The provision of such motors with reverse rotation or transmission means makes the solid scraper (900) complex and expensive.

[0032] US2013168317 discloses a method and apparatus for the treatment of tar or resin liquid suspensions derived from the gasification, pyrolysis, or drying of biomass.

[0033] US5338285A discloses a rotary discharged type centrifugal separator having a pantograph link-type scraper.

[0034] The purpose of the present invention is to overcome the drawbacks of the prior art by devising a solid residue recovery unit comprising an effective and efficient solid scraper capable of adequately scraping almost the entire inner surface of the side wall of the box body.

[0035] A further purpose of the present invention is to devise a solid residue recovery unit that is simple and inexpensive to make.

[0036] Finally, another purpose of the present invention is to devise a new solid residue recovery unit wherein the solid scraper does not necessarily need to rotate in two opposite directions. These purposes are achieved in accordance with the invention with the characteristics listed in the appended independent claim 1 .

[0037] Advantageous embodiments appear from the dependent claims.

[0038] The solid residue recovery unit according to the invention is defined by claim 1 .

[0039] For the sake of clarity, the description of the solid residue unit according to the invention continues with reference to the appended drawings, which are for illustrative, not-limiting value, wherein:

[0040] Fig. 1 Prior Art is a schematic side view of a conventional decanter or centrifugal separator / extractor;

[0041] Fig. 2 is a schematic axonometric view of a box body defining a collection chamber for the solid residues ejected from the ejection flange of the rotating drum of the decanter of Fig. 1 ;

[0042] Figs. 3, 3A, and 3B Prior Art are schematic front views of a solid residue recovery unit according to the prior art, consisting of a box body and a solid scraper arranged inside the collection chamber defined by the box body; wherein said Figs. 3, 3A, and 3B are a step-by-step representation of the movement performed by the solid scraper inside the box body;

[0043] Fig. 4 is an exploded axonometric view of the solid residue recovery unit according to the invention;

[0044] Fig. 5 is an axonometric view of the solid residue unit according to the invention in assembled condition;

[0045] Fig. 6 shows the solid residue unit according to the invention in assembled condition, wherein a wall of the box body is omitted to show the solid scraper arranged inside the box body;

[0046] Figs. 7 and 8 are two different axonometric views of the box body, without a wall, and of the solid scraper disassembled from each other;

[0047] Fig. 7A is an enlargement of a detail of Fig. 7 illustrating in particular the housing and guiding means for the side arms of the solid scraper of the solid residue recovery unit according to the invention;

[0048] Fig. 8A is an enlargement of the parts of the solid residue recovery unit according to the invention shown in Fig. 8; Figs. 9, 9A, 9B, and 9C are schematic front views of the solid residue recovery unit according to the invention; wherein Figs. 9, 9A, 9B, and 9C are a step-by-step representation of the movement performed by the solid scraper inside the box body of the solid residue recovery unit according to the invention.

[0049] With reference to Figs. 4-9C, a new solid residue recovery unit according to the invention is described, which is generally indicated with the reference letter “Q”.

[0050] The solid residue recovery unit (Q) according to the invention is suitable for being an integral part of a conventional decanter (D) of a centrifugal separator for the processing of food and non-food products, such as oleaginous fruits, industrial sludge, slop oil, and other food or industrial products in general.

[0051] The decanter (D) has been described previously in the prior art and is schematically shown in Fig. 1 , therefore, for the sake of brevity, the parts of the decanter (D) will not be described again here. However, the general structure of the decanter (D) shown in Fig. 1 should be understood as generally known, and therefore, for the construction of the parts of the decanter (D) that are not of interest for the present invention, such as the rotating drum (T), the screw conveyor (C), and the fixed frame (F), reference can be made to any known type of decanter.

[0052] As mentioned above, the present invention relates in particular to a new solid residue recovery unit (100) suitable for being arranged at the end of the conical section of the rotating drum (T) of the decanter (D).

[0053] The solid residue recovery unit (Q) comprises a box body (1 ) defining a collection chamber (10) wherein the ejection flange (G) of the rotating drum (T) of the decanter (D) is suitably arranged.

[0054] The box body (1 ) comprises:

[0055] - a first edge (1 1 ) with a hole (11 1 ) wherein the conical section (T2) of the rotating drum (T) of the decanter (D) attached to the ejection flange (G) is suitable for being rotatably and thoroughly inserted;

[0056] - a second edge (12) parallel to the first edge (1 1 ) with a hole (122) coaxial with the hole (1 1 1 ). The hole (122) of the second edge (12) is suitable for being closed by a plug (TP), as shown in Fig. 5.

[0057] The box body (1 ) further comprise a side wall (13) joining the first edge (1 1 ) with the second edge (12) and comprising two vertical sections (131 ) parallel to each other and a curvilinear upper section (132) extending over an arc of a circumference of approximately 180°.

[0058] The box body (1 ) is open at the bottom and has a lower discharge outlet (14) suitable for being crossed by the solid residue.

[0059] With reference to Figs. 4 and 6, the solid residue recovery unit (Q) also comprises a solid scraper (100) arranged in the collection chamber (10).

[0060] The solid scraper (100) comprises:

[0061] - two side arms (2), each one extending alongside a vertical section (131 ) of the side wall (13) of the box body (1 ); each side arm (2) has an upper end section (21 ) and a lower end section (22);

[0062] - an arch (3) extending superiorly and laterally relative to the hole (11 1 ) of the first edge (1 1 ) and in the vicinity of the curvilinear upper section (132) of the side wall (13); the arch (3) has a central section (30) and two end sections (31 ) hinged to the upper end sections (21 ) of the two side arms (2) by means of pivoting pins (K); and

[0063] - a plurality of scraping tools (4) protruding outwardly from the arch (3) and from the side arms (2) and suitable for scraping an inner surface of the side wall (13) of the box body (1 ) to remove the solid residues (s) adhered to the inner surface of the side wall (13).

[0064] The solid residue recovery unit (Q) also comprises a driving assembly (5) connected to the solid scraper (100) to move the solid scraper (100) inside the collection chamber (10).

[0065] With reference to Figs. 7, 8, and 8A, the driving assembly (5) comprises:

[0066] - a rotating shaft (51 ) that is positioned at a higher height than the holes (1 1 1 , 122) and has a longitudinal axis (X) parallel to the central axis of the two holes (11 1 , 122) that are coaxial with each other; the rotating shaft (51 ) is rotatably and thoroughly inserted into a respective hole (FX) preferably formed on the first edge (1 1 ) of the box body (1 ); the rotating shaft (51 ) has a first end (51 1 ) located outside the collection chamber (10) and a second end (512) located inside the collection chamber (10);

[0067] - a rotating means (50) connected to the first end (51 1 ) of the rotating shaft (51 ) and configured to rotate the rotating shaft (51 ) about its longitudinal axis (X); and

[0068] - a connection body (52) that is rotatably integral with the rotating shaft (51 ), namely at the second end (512) of the rotating shaft (51 ), and eccentrically connects the central section (30) of the arch (3) to the rotating shaft (51 );

[0069] - integral coupling means (531 , 532) that rotatably and integrally couple the connection body (52) to the rotating shaft (51 ) (namely, to the second end of the rotating shaft (51 )) in such a way that the connection body (52) is driven into rotation by the rotating shaft (51 ); and

[0070] - rotatable coupling means (54) that rotatably connect the central section (30) of the arch (3) to the connection body (52) around an axis parallel to the axis of rotation of the rotating shaft (51 ) of the driving assembly (5).

[0071] With reference to Fig. 8A, the connection body (52) consists of a rotating arm (520) that extends radially with respect to the axis of the rotating shaft (51 ) and rotates together with the rotating shaft (51 ).

[0072] The rotating arm (520) has:

[0073] - a first end (521 ) integrally and rotatably connected to the rotating shaft (51 ) by means of the integral coupling means (531 , 532), so that the rotating arm (520) rotates together with the rotating shaft (51 );

[0074] - a second end (522) rotatably coupled in idle to the central section (30) of the arch (3) of the solid scraper (100) by means of the rotatable coupling means (54).

[0075] In particular, the connection body (52), which consists of the rotating arm (520), has a first hole (521 f) formed on the first end (521 ) of the rotating arm (520), and a second hole (522f) formed on the second end (522) of the rotating arm (520).

[0076] The rotatable coupling means (54) comprise a pin that is rotatably inserted both in the second hole (522f) of the connection body (52) and in a hole formed on the central section (30) of the arch (3). The second end (512) of the rotating shaft (51 ) is inserted into the first hole (521 f) of the connection body.

[0077] The integral coupling means (531 , 532) are formed between the inner surface of the first hole (521 f) and the outer surface of the second end (522) of the rotating shaft (51 ) and are configured to provide a prismatic coupling between the rotating shaft (51 ) and the connection body (52) such that the rotating shaft (51 ) can slide, but not rotate, relative to the connection body (52).

[0078] By way of example, the integral coupling means (531 , 532) comprise at least one rib (531 ) formed on the outer surface of the second end (512) of the rotating shaft (51 ) and a corresponding groove (532) formed on the inner surface of the first hole (521 f) of the connection body (52) suitable for accommodating the rib (531 ).

[0079] Alternatively, the integral coupling means (531 , 532) may comprise any other means known to a technician in the field that provide a prismatic coupling between the rotating shaft (51 ) and the connection body (52).

[0080] Likewise, the first end (51 1 ) of the rotating shaft (51 ) is coupled to the rotating means (50) by means of a prismatic coupling, so that the rotating shaft (51 ) can slide, but not rotate, relative to the rotating means (50). Therefore, the rotating shaft (51 ) can slide freely along its longitudinal axis (X) both relative to the rotating means (50) and to the connection body (52).

[0081] The rotating means (50) comprise:

[0082] - a motor (501 );

[0083] - a motor ring (502) having a central hole (502f) wherein the first end (51 1 ) of the rotating shaft (51 ) is inserted with a prismatic coupling; and

[0084] - driving means (not shown in the appended figures) that transmit the motion of the motor (501 ) to the motor ring (502).

[0085] The prismatic coupling between the first end (51 1 ) of the rotating shaft (51 ) and the hole (502f) of the motor ring (502) is achieved by means of a rib (5n) formed on the first end (51 1 ) of the rotating shaft (51 ) and a groove (5s) formed on the central hole (502f) of the motor ring (502) that extends for the entire depth of the central hole (502f). With reference to Fig. 8, the rotating shaft (51 ) is rotatably supported by a conventional support unit (59) which is connected to the box body (1 ). The support unit (59) comprises mechanical seals, oil seals, bearings, etc., crossed by the rotating shaft (51 ).

[0086] With reference to Fig. 8A, each scraping tool (4) comprises a U-shaped plate with a concavity facing the solid scraper (100), comprising:

[0087] - a central section (40) fixed to the solid scraper (100) and suitable for scraping the inner surface of the side wall (13) of the box body (1 ); and

[0088] - two lateral sections (41 ) parallel to each other, arranged anteriorly and posteriorly to the solid scraper (100) and suitable for grazing the internal surface of the first edge (1 1 ) of the box body (1 ) and the internal surface of the second edge (12) of the box body (1 ).

[0089] As shown in Fig. 6, each lower end section (22) of a side arm (2) is not constrained to the lower end section (22) of the other side arm (2). Otherwise said, the two lower end sections (22) are not connected to each other by means of bars or other articulated systems.

[0090] With reference to Figs. 6 and 7, the solid residue recovery unit (Q) comprises housing and guiding means (6) wherein the lower end sections (22) of the side arms (2) are inserted and configured to guide and limit the rotary- translatory movement of the side arms (2) during the movement of the solid scraper (100) driven by the driving assembly (5).

[0091] In particular, the housing and guiding means (6) comprise two means (6', 6"), one for each side arm (2), one of which is fixed to a vertical section (131 ) of the side wall (13) and the other is fixed to the other vertical section (131 ) of the side wall (13).

[0092] Each of said means (6', 6") is configured to define a passageway (60) wherein the respective side arm (2) is inserted.

[0093] The passageway (60) of each means (6', 6") is dimensioned in such a way as to:

[0094] - prevent the side arm (2) from moving along a direction parallel to the longitudinal axis (X) of the rotating shaft (51 ); and - allow the side arm (2) to move (roto-translate) along a plane orthogonal to the longitudinal axis (X) of the rotating shaft (51 ) .

[0095] With reference to Fig. 7A, each means (6', 6") of said housing and guiding means (6) comprises:

[0096] - a U-shaped bracket (61 ) comprising a central section (610) fixed to one of the two vertical sections (131 ) of the side wall (13), and two parallel sections (61 1 ) protruding orthogonally from the central section;

[0097] - two stop pegs (62) parallel to each other and extending between the two parallel sections (61 1 ) of the U-shaped bracket (61 ).

[0098] The parallel sections (61 1 ) and the stop pegs (62) define the passageway (60) wherein the lower end section (22) of the side arm (2) of the solid scraper (100) is inserted.

[0099] Following to numerous experimental tests, the applicant has found that, thanks to the particular new configuration of the solid residue recovery unit (Q), the scraping tools (4) of the solid scraper (100) are able to reach and graze the large majority of the internal surface of the side wall (13) and of the edges (1 1 , 12) of the box body (1 ), thus intercepting and removing a large quantity of solid residue that adheres to the inner surface of the side wall (13) and of the edges (1 1 , 12).

[0100] In fact, with reference to Figs. 9-9C, it can be seen how the scraping tools (4) of the solid scraper (100) are able to graze the large majority of the internal surface of the side wall (13) of the box body (1 ).

[0101] Furthermore, thanks to the provision of the new solid residue recovery unit (Q), the rotating shaft (51 ) can be constantly rotated by 360° always in the same direction (VV) (see Figs. 9-9C) and therefore it is no longer necessary (unlike the solid residue unit of the prior art) to use motors with reverse rotation or transmission systems that allow an oscillatory motion to be generated.

[0102] Numerous variations and detailed modifications can be made to the present embodiment of the invention, within the reach of a person skilled in the art, however falling within the scope of the invention as expressed by the appended claims.

Claims

CLAIMS1. Solid residue recovery unit (Q) of a decanter (D) of a centrifugal separator; said solid residue recovery unit (Q) comprising: a) a box body (1 ) defining a collection chamber (10) wherein an ejection flange (G) of a rotating drum (T) of a decanter (D) is suitably arranged to eject solid residue inside the collection chamber (10); b) a solid scraper (100) disposed in the collection chamber (10); c) a driving assembly (5) connected to the solid scraper (100) to move the solid scraper (100) inside the collection chamber (10); wherein said box body (1 ) comprises:- a first edge (1 1 ) with a hole (1 11 ) wherein a conical section (T2) of the rotating drum (T) of the decanter (D) attached to the ejection flange (G) is suitable for being rotatably and thoroughly inserted;- a second edge (12) parallel to the first edge (1 1 );- a side wall (13) joining the first edge (1 1 ) with the second edge (12) and comprising two vertical sections (131 ) parallel to each other and a curvilinear upper section (132) extending over an arc of a circumference;- a lower discharge outlet (14) suitable for being crossed by the solid residue; wherein said solid scraper (100) comprises:- two side arms (2), each one extending alongside a vertical section (131 ) of the side wall (13); each side arm (2) comprising an upper end section (21 ) and a lower end section (22);- an arch (3) extending superiorly and laterally to the hole (1 1 1 ) of the first edge (11 ) and in the vicinity of the curvilinear upper section (132) of the side wall (13); the arch (3) has a central section (30) and two end sections (31 ) hinged to the upper end sections (21 ) of the two side arms (2) by means of pivoting pins (K);- a plurality of scraping tools (4) protruding outwardly from the arch (3) and from the side arms (2) and suitable for scraping an inner surface of theside wall (13) of the box body (1 ) to remove the solid residue adhered to the inner surface of the side wall (13); characterized in that said driving assembly (5) comprises:- a rotating shaft (51 ) that is positioned at a higher height than the hole (1 1 1 ) of the first edge (1 1 ) and has a longitudinal axis (X) parallel to the central axis of the hole (1 1 1 ); the rotating shaft (51 ) has a first end (511 ) located outside the collection chamber (10) and a second end (512) located inside the collection chamber (10);- a rotating means (50) connected to the first end (51 1 ) of the rotating shaft (51 ) and configured to rotate the rotating shaft (51 ) about its longitudinal axis (X);- a connection body (52) that is rotatably integral with the second end (512) of the rotating shaft (51 ) and rotatably and eccentrically connects the central section (30) of the arch (3) to the rotating shaft (51 );- integral coupling means (531 , 532) that rotatably and integrally couple the connection body (52) to the rotating shaft (51 );- rotatable coupling means (54) that rotatably connect the central section (30) of the arch (3) to the connection body (52).

2. The solid residue recovery unit (Q) according to claim 1 , wherein each lower end section (22) of a side arm (2) is not constrained to the lower end section (22) of the other side arm (2); wherein said solid residue recovery unit (Q) comprises housing and guiding means (6) wherein the lower end sections (22) of the side arms (2) are inserted.

3. The solid residue recovery unit (Q) according to claim 2, wherein the housing and guiding means (6) comprise two means (6', 6"), one for each side arm (2), one of which is attached to a vertical section (131 ) of the side wall (13) and the other of which is attached to the other vertical section (131 ) of the side wall (13); wherein each one of said means (6', 6") defines a passageway (60) wherein the lower end section (22) of the respective side arm (2) is inserted.

4. The solid residue recovery unit (Q) according to claim 3, wherein each means (6', 6") of said housing and guiding means (6) comprises:- a U-shaped bracket (61 ) comprising a central section (610) attached to one of the two vertical sections (131 ) of the side wall (13) and two parallel sections (61 1 ) projecting orthogonally from the central section (610);- two stop pegs (62) parallel to each other and extending between the two parallel sections of the U-shaped bracket (61 ); wherein said parallel sections (61 1 ) and said stop pegs (62) define the passageway (60) wherein the lower end section (22) of the side arm (2) of the solid scraper (100) is inserted.

5. The solid residue recovery unit (Q) according to any of the preceding claims, wherein each scraping tool (4) comprises a U-shaped plate with concavity facing the solid scraper (100).

6. The solid residue recovery unit (Q) according to any of the preceding claims, wherein the connection body (52) of the driving assembly (5) has a first hole (521 f) and a second hole (522f); wherein the rotatable coupling means (54) comprise a pin that is rotatably inserted into the second hole (522f) of the connection body (52) and into a hole formed on the central section (30) of the arch (3); wherein the second end (512) of the rotating shaft (51 ) is inserted into the first hole (521 f) of the connection body (52); wherein said integral coupling means (531 , 532) are formed between the inner surface of the first hole (521 f) and the outer surface of the second end (522) of the rotating shaft (51 ) and are configured to provide a prismatic coupling between the rotating shaft (51 ) and the connection body (52), such that the rotating shaft (51 ) can slide, but not rotate, relative to the connection body (52).

7. The solid residue recovery unit (Q) according to claim 6, wherein the first end (51 1 ) of the rotating shaft (51 ) is coupled to the rotating means (50) by means of a prismatic coupling, such that the rotating shaft (51 ) can slide, but not rotate, relative to the rotating means (50).

8. The solid residue recovery unit (Q) according to any of the preceding claims, comprising a support unit (59) that is connected to the box body (1 ) and rotatably supports said rotating shaft (51 ).

9. Decanter (D) of a centrifugal separator comprising:- a fixed frame (F);- a rotating drum (T) rotatably mounted on the fixed frame (F) and comprising a cylindrical section (T1 ) and a conical section (T2) provided with an ejection flange (G);- a screw conveyor (C) rotatably inserted inside the rotating drum (T); the screw conveyor (C) has a longitudinal channel wherein the product to be separated is fed and holes for the ejection of the product to be separated so that the product is poured inside the rotating drum (T);- a solid residue recovery unit (Q) according to any of the preceding claims disposed at the end of the conical section (T2) of the rotating drum (T); wherein said conical section (T2) of the rotating drum (T) is thoroughly inserted in the hole (111 ) formed on the first edge (11 ) of the box body (1 ) of the solid residue recovery unit (Q) and said ejection flange (G) of the conical section (T2) of the rotating drum (T) is disposed inside the collection chamber (10) of the box body (1) of the solid residue recovery unit (Q).

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