Wear assembly for a helically formed metal decanter screw conveyor

Abstract

The present invention relates to a wear assembly for a metal screw conveyor formed in a spiral shape of a decanter centrifuge. The assembly includes a wear plate that defines, on the rear surface of the wear plate, a wear plate connection surface that extends substantially longitudinally and a wear plate contact surface that extends substantially parallel to the upper end of the wear plate. The assembly further includes a support plate that defines, on the front surface of the support plate, a support plate connection surface for engaging with the wear plate connection surface. The support plate further defines, on the front surface of the support plate, a support plate contact surface for contacting the wear plate contact surface when the support plate connection surface is engaged with the wear plate connection surface.

Description

Technical Field

[0001] The present invention relates to a wear assembly for a metallic screw conveyor formed in a spiral shape of a decanter centrifuge, a metallic screw conveyor formed in a spiral shape for a decanter centrifuge, and a method of attaching the wear assembly to the metallic screw conveyor formed in a spiral shape for a decanter centrifuge.

Background Art

[0002] Decanter centrifuges are used in various applications for separating feed raw materials consisting of solid / liquid mixtures into light phase (liquid) and heavy phase (solid) components. A decanter centrifuge includes a rotatable bowl and a metallic screw conveyor formed in a spiral shape rotatable on a common axis. The feed raw material is typically injected into the center of the decanter centrifuge, separated into the heavy phase and the light phase, and discharged at large, conical ends on opposite sides of the bowl, respectively. The light phase is collected near the axis and discharged at the large end, while the heavy phase accumulates on the inner surface of the bowl wall and is conveyed by a metallic screw conveyor formed in a spiral shape, which rotates at a speed slightly different from the rotational speed of the bowl, to the outlet at the conical end.

[0003] When the heavy phase is corrosive, it is necessary to make the screw conveyor wear-resistant in order to extend the life of the screw conveyor. Corrosive feed raw materials are found, for example, in the mining industry (such as rocks), the petroleum industry (such as sands), and the food industry (such as seeds). The conveyor can be made wear-resistant by providing a wear plate of wear-resistant material at the end of the screw conveyor. Due to the corrosiveness of the feed raw material, laser cladding or laser brazing of the wear plate is not preferred. It is preferable to purely mechanically attach the wear plate onto a support plate forming the assembly. In that case, the assembly can be attached to the end of the screw conveyor by fixing the support plate to the end of the screw conveyor by welding, brazing, or similar fixing techniques.

[0004] Patent Document 1 discloses a decanter centrifuge having a ceramic element connected to a support body by a double-tail connection.

[0005] Patent Document 2 discloses a screw centrifuge provided with a series of thin ceramic plates fixed adjacent to each other at the outer end of the screw. The plates have at least two formed ceramic protrusions protruding from the thin ceramic plates, and are arranged in recesses outlined by the protrusions.

[0006] Patent Document 3 discloses a screw centrifuge provided with a wear-resistant plate having elastic rubber between a wear plate and a support plate. It can also have a pin-shaped extension.

[0007] Patent Document 4 discloses a decanter centrifuge having a wear-resistant member provided with a double-tail protrusion having a threaded hole.

[0008] Patent Document 5 discloses a centrifuge provided with tiles having double-tails. The tile carrier includes a double-tail slot or groove defined between upper and lower lip portions that are adapted to be engaged by the lip portion of the tile during use.

[0009] Patent Document 6 discloses a tile body and a tile tip having a protrusion for fixing and a hole for fixing, respectively, on one side. The protrusion for fixing and the hole for fixing are combined with each other.

[0010] Patent Document 7 discloses a multi-layer laminated wear-resistant assembly provided with brackets stacked between plates of wear-resistant material. The layers of the assembly are fixed together by soldering, brazing, or some other method. The bracket material is confined between two layers of harder material and remains in an extended state.

[0011] Patent Document 8 discloses a centrifuge decanter having a tilting double tail lock. The support plate has an opening into which the wear tile is inserted. The opening forms an upper corner that allows the male corner of the wear tile to be inserted.

[0012] Both Patent Document 9 and Patent Document 10 disclose a centrifuge decanter having a wear-resistant member with a mating surface that mechanically connects the wear-resistant member to the support plate. The mating surface prevents the radially outward movement of the wear-resistant member.

[0013] Patent Document 11 discloses a centrifuge decanter having a wear-resistant member attached along the end of a screw conveyor. The member has a double tail projection on its back surface. The projection tapers in the radial width. The member can be directly engaged with each of its support plates by a substantially radial sliding movement with respect to the axis of the screw.

[0014] Patent Document 12 relates to a conveyor screw having a support plate and tiles that are engaged with the support plate by a radial sliding movement. Each tile has its radially inward movement retained only by contact with an adjacent tile.

[0015] Having a mating surface that mechanically connects a wear-resistant member to a support plate and prevents the radially outward movement of the wear-resistant member means that if the wear-resistant plate wears against the mating surface, the wear-resistant member may become loose. In that case, the wear-resistant member may be thrown towards the inner surface of the bowl wall and may cause significant damage to the bowl wall.

[0016] Having a double-tail protrusion that tapers in width in the radial direction enables the wear-resistant plate to be maintained in a fixed position even when the wear-resistant member is worn down. However, since the tapered protrusion is directed radially towards the bowl wall, the tapered protrusion is susceptible to manufacturing tolerances. Even a slight deviation in the measurement of the tapered protrusion can result in a large deviation of the wear plate in the radial direction. Therefore, the wear plate may extend too far radially and damage the inner wall of the bowl.

Prior Art Documents

Patent Documents

[0017]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

Patent Document 11

Patent Document 12

Summary of the Invention

Problems to be Solved by the Invention

[0018] Therefore, an object of the present invention is to provide a technique for avoiding the aforementioned drawbacks of the prior art.

Means for Solving the Problems

[0019] The above object is achieved, in a first aspect, by a wear assembly for a metal screw conveyor formed in a spiral shape of a decanter centrifuge, the assembly comprising: a wear plate defining a wear plate front surface and a wear plate rear surface, the wear plate rear surface defining a wear plate upper end portion, a wear plate lower end portion, and two opposed wear plate side end portions connecting the wear plate upper end portion and the wear plate lower end portion to each other, the wear plate rear surface further defining a longitudinal direction extending from the wear plate lower end portion to the wear plate upper end portion, the wear plate defining, on the wear plate rear surface, a wear plate connection surface extending substantially in the longitudinal direction and a wear plate contact surface extending substantially parallel to the wear plate upper end portion on the wear plate rear surface, the wear plate; a support plate defining a support plate front surface and a support plate rear surface, the support plate rear surface being attachable to a metal screw conveyor formed in a spiral shape, the support plate defining, on the support plate front surface, a support plate connection surface for engaging with the wear plate connection surface, the support plate further defining, on the support plate front surface, a support plate contact surface for contacting the wear plate contact surface when the support plate connection surface is engaged with the wear plate connection surface, the support plate; and.

[0020] The wear assembly is mounted in parallel at the end on a metal screw conveyor formed in a spiral shape of a decanter centrifuge. The wear plate has a connection surface that extends substantially in the longitudinal direction. The wear plate connection surface mainly faces the side end of the wear plate. When the front surface of the support plate engages with the wear plate connection surface, the wear plate connection surface faces and engages with the support plate connection surface to hold the rear surface of the wear plate against movement in a direction away from the front surface of the support plate, that is, to prevent separation between the wear plate and the support plate. The wear plate connection surface and the support plate connection surface should be appropriately formed to prevent such separation when the wear plate connection surface and the support plate connection surface engage. The wear plate connection surface also faces and engages with the support plate connection surface to hold the wear plate against lateral movement, that is, in the direction between the side ends.

[0021] When the support plate connection surface engages with the wear plate connection surface, the support plate abutment surface will contact the wear plate abutment surface to hold the wear plate longitudinally with respect to the support plate. Since the wear plate abutment surface extends substantially parallel to the upper end of the wear plate, the wear plate abutment surface provides a well-defined stop for the wear plate with respect to the support plate, preventing the upper end from extending too far towards the inner wall of the bowl. The distance between the upper end of the wear plate and the inner wall of the bowl can thus be determined and controlled very precisely. Slight manufacturing errors in the plate only have a slight effect on the distance between the upper end and the bowl. In comparison, if the distance between the upper end of the wear plate and the inner wall of the bowl is determined by the contact between the tapered wear plate connection surface and the support plate connection surface that extends substantially in the longitudinal direction, slight manufacturing errors in the plate will have a large effect on the distance between the upper end and the inner wall of the bowl.

[0022] The abutment surface of the support plate is preferably complementary to the abutment surface of the wear plate. Thus, the abutment surface of the support plate contacts the abutment surface of the wear plate along a contact line substantially parallel to the upper end of the wear plate. The abutment surface of the wear plate is preferably located adjacent to the upper end, but may also be located adjacent to the lower end.

[0023] According to a further embodiment of the first aspect, the connection surface of the support plate engages with the connection surface of the wear plate by a sliding operation between the rear surface of the wear plate and the front surface of the support plate in the longitudinal direction of the wear plate.

[0024] The sliding operation enables the connection surface of the wear plate and the connection surface of the support plate to be engaged in an easy and reliable manner, and enables the abutment surface of the wear plate to contact the abutment surface of the support plate.

[0025] According to a further embodiment of the first aspect, the connection surface of the support plate and the connection surface of the wear plate define a protrusion and a complementary-shaped slot into which the protrusion engages.

[0026] The protrusion engaging in the slot holds the rear surface of the wear plate against movement in a direction away from the front surface of the support plate, i.e., prevents separation between the wear plate and the support plate.

[0027] According to a further embodiment of the first aspect, the protrusion is provided on the wear plate and the slot is formed in the support plate.

[0028] Thereby, the wear plate is supported by the support plate, which is beneficial since the wear plate is usually more brittle than the support plate.

[0029] According to a further embodiment of the first aspect, the protrusion has a double-tail cross-section.

[0030] The cross-section of the double-tail of the protrusion will hold the rear surface of the wear plate against movement away from the front surface of the support plate, i.e., prevent separation between the wear plate and the support plate.

[0031] According to a further embodiment of the first aspect, the protrusion and the slot have a tapered shape with a longitudinally decreasing width.

[0032] In this way, the wear plate is restricted longitudinally even when the wear plate contact surface and the support plate contact surface are worn. This allows the wear plate contact surface to be located near the upper end of the wear plate. When the wear plate contact surface is worn, the movement of the wear plate relative to the support plate in the longitudinal direction will be limited by the contact of the wear plate connection surface with the support plate connection surface. This prevents the wear plate from becoming loose and being thrown towards the inner surface of the bowl wall even when the contact surfaces are worn. When the contact surfaces are worn, since the wear plate connection surface contacts the support plate connection surface, there is only a slight movement of the wear plate relative to the support plate in the longitudinal direction.

[0033] According to a further embodiment of the first aspect, the assembly further comprises a lock plate that can be attached to the support plate at the lower end of the wear plate to hold the wear plate against the support plate in a direction from the upper end to the lower end of the wear plate when the wear plate engages with the support plate.

[0034] A lock plate can be used to hold the wear plate in a direction opposite to the longitudinal direction with respect to the support plate. The wear plate is positioned between the lock plate and the inner wall of the bowl and thus does not come into significant contact with the solid portion of the supplied raw material, and therefore it does not wear significantly. Preferably, the lock plate holds pressure on the lower end of the wear plate in the longitudinal direction so that the contact surface of the wear plate contacts the contact surface of the support plate reliably. The lock plate can be spot welded to the support plate.

[0035] According to a further embodiment of the first aspect, the lock plate has a protrusion that protrudes into the complementary slot of the wear plate when the wear plate engages with the support plate.

[0036] The protrusion and the complementary slot can be used to lock the wear plate securely in the central position with respect to the support plate and / or to prevent any lateral movement.

[0037] According to a further embodiment of the first aspect, a rubber film is provided between the wear plate and the support plate, and the rubber film is preferably applied to the rear surface of the wear plate and / or the front surface of the support plate by spraying.

[0038] Having a rubber film between the wear plate and the support plate can avoid cracking of the wear plate and provide a certain degree of elasticity to the assembly.

[0039] According to a further embodiment of the first aspect, the support plate has a wear indicator on the rear surface.

[0040] The wear indicator can be in the form of a worn marking or rib, and thus indicates when the wear assembly should be replaced.

[0041] According to a further embodiment of the first aspect, the upper end portion is between 10 mm and 100 mm, preferably between 25 mm and 75 mm.

[0042] The wear assembly should preferably have the above measurements that can be incorporated into a typical decanter centrifuge.

[0043] According to a further embodiment of the first aspect, the support plate is made of a material softer than the wear plate, and the wear plate is preferably made of carbide such as tungsten carbide, ceramic, polyurethane, or polyurea, and the support plate is preferably made of steel such as stainless steel.

[0044] The wear plate can be made of a material harder than the support plate to withstand wear. The support plate can be made of a soft material attached to the end of a helically formed metal screw conveyor by welding, brazing, or the like. The above materials are suitable as the wear plate and the support plate, respectively.

[0045] The above object is achieved, in the second aspect, by a helically formed metal screw conveyor for a decanter centrifuge comprising one or more wear assemblies according to any of the embodiments of the first aspect, wherein the back surface of the support plate is attached to the end of the helically formed metal screw conveyor, and the longitudinal direction corresponds to the radially outward direction from the axis of the helically formed metal screw conveyor.

[0046] The wear assembly is first mechanically assembled and then attached to the upper end portion of the helically formed metal screw conveyor. The support plate is fixed to the helically formed metal screw conveyor, while the wear plate should face outward in the direction of the helically formed metal screw conveyor with respect to the axis of rotation. Usually, several wear assemblies are assembled and attached along the end of the helically formed metal screw conveyor.

[0047] According to a further embodiment of the second aspect, the wear assembly is attached to the helically formed metal screw conveyor by a welded joint at the end of the helically formed metal screw conveyor.

[0048] The support plate of the assembly is usually attached to the end of the metal screw conveyor by welding. Further welding can be performed on the front surface of the helically formed metal screw conveyor at the intersection between the support plate and the helically formed metal screw conveyor on the side opposite to the upper end. It is preferable that MMA, TIG, or MAG welding can be used.

[0049] In the third aspect, the above object is achieved by a method of attaching a wear assembly to a helically formed metal screw conveyor for a decanter centrifuge, and the assembly is a wear plate defining a wear plate front surface and a wear plate rear surface, the wear plate rear surface defines a wear plate upper end, a wear plate lower end, and two opposite wear plate side ends connecting the wear plate upper end and the wear plate lower end to each other, the wear plate rear surface further defines a longitudinal direction extending from the wear plate lower end to the wear plate upper end, the wear plate defines, on the wear plate rear surface, a wear plate connection surface extending substantially in the longitudinal direction and a wear plate abutment surface extending substantially parallel to the wear plate upper end on the wear plate rear surface, the wear plate and a support plate defining a support plate front surface and a support plate rear surface, the support plate rear surface is attachable to the helically formed metal screw conveyor, the support plate defines a support plate connection surface on the support plate front surface, the support plate further defines a support plate abutment surface on the support plate front surface, the support plate and and the method includes engaging the support plate connection surface with the wear plate connection surface, and contacting the support plate abutment surface with the wear plate abutment surface, and performing.

[0050] The method according to the third aspect preferably uses a wear plate assembly according to any of the embodiments of the first aspect. For example, the wear plate is preferably engaged with the support plate by a sliding operation. Further steps can include welding a lock plate to the support plate. The assembly is then welded to a helically formed metal screw conveyor.

Brief Description of the Drawings

[0051]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 2C

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Figure 4C

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0052] Figure 1A shows a decanter centrifuge 10 having a helically formed metal screw conveyor 12 located within a cylindrical bowl 14 of the decanter centrifuge 10. The position of the wear assembly 16 is shown in the enlarged view of Figure 1B.

[0053] The screw conveyor 12 is provided with a plurality of wear assemblies 16 located at the outer end 18 of the screw conveyor 12. Each wear assembly 16 includes a wear plate 20, a support plate 22, and a lock plate 24. The wear assembly 16 is first assembled and then fixed to the outer end 18 of the screw conveyor 12.

[0054] The wear plate 20 includes a wear plate front surface 26 and an opposite wear plate rear surface (not visible) that is mechanically fixed to the front surface (not visible) of the support plate 22. The wear plate front surface 26 includes an upper end 28, a lower end 30, and two opposite side ends 32, 34 that interconnect the upper end 28 and the lower end 30.

[0055] The wear plate 20 is mechanically fixed on the support plate 22 such that the upper end 28 of the wear plate is positioned adjacent to the bowl wall 14 but avoids contact with the bowl wall 14. The lock plate 24 is typically fixed on the support plate 22 adjacent to the lower end 30 by spot welding. The lock plate 24 holds the wear plate 20 in place. The wear assembly 16 is then welded (not shown) to the screw conveyor 12 at the outer end 18 of the helically formed metal screw conveyor. Additional welding (not shown) can be performed on the front surface of the helically formed metal screw conveyor 12 at the intersection of the support plate 22 and the helically formed metal screw conveyor 12 on the opposite side of the outer end 18. It is preferable that MMA, TIG, or MAG welding can be used.

[0056] The support plate 22 further includes a wear indicator 36 that indicates wear in the wear assembly 16. The wear indicator 36 includes a worn-down protrusion as an indication of wear when the wear assembly 16 is worn.

[0057] The wear plate 20 is made of a wear-resistant material such as tungsten carbide, ceramic, polyurethane, or polyurea, and the support plate 22 is made of a weldable material such as steel, usually stainless steel. The lock plate 24 is usually made of the same weldable material as the support plate 22. The wear plate 20 protects the support plate 22 and the helically formed metal screw conveyor 12 against excessive wear.

[0058] FIG. 2A shows a side view of the wear assembly 16 according to the first embodiment together with the end 18 of the screw conveyor. The wear plate 20 is engaged with the support plate 22 as indicated by the arrow. The rear surface 38 of the wear plate 20 is mechanically attached to the front surface 40 of the support plate 22. The support plate 22 is welded to the screw conveyor at the outer end.

[0059] FIG. 2B shows a perspective view of the engagement procedure of the wear plate 20 onto the support plate 22. The rear surface 38 of the wear plate 20 includes protrusions 46. The protrusions 46 have a double-tail shape that tapers towards the upper end 28 of the wear plate. The protrusions 46 engage, by a sliding movement as indicated by the arrow, with complementary slots (not visible) on the front surface (not visible) of the support plate. The protrusions 46 include two opposing wear plate connection surfaces 42 extending along the side ends 32, 34 and a wear plate abutment surface 44 extending substantially parallel to the upper end 28 of the wear plate 20.

[0060] Figure 2C shows a second perspective view of the engagement procedure of the wear plate 20 with the support plate 22. The front surface 40 of the support plate includes two opposing support plate connection surfaces 48 extending along the side ends 32, 34, and a support plate abutment surface 50. The front surface 40 of the support plate 22 includes a slot 52, which is complementary to a protrusion (not visible) of the wear plate 20, into which a protrusion (not visible) on the rear surface (not visible) of the wear plate is engaged as indicated by the arrow. In this way, the wear plate 20 engages with the support plate 22.

[0061] When the protrusion (not visible) engages with the slot, the wear plate connection surface (not visible) faces and engages with the support plate connection surface to hold the rear surface 38 of the wear plate against movement away from the front surface 40 of the support plate, that is, to prevent separation between the wear plate 20 and the support plate 22. This is achieved by the double-tail configuration of the protrusion 46 and the complementary shape of the slot 52.

[0062] When the support plate connection surface 48 engages with the wear plate connection surface (not visible), the wear plate abutment surface (not visible) contacts the support plate abutment surface 50 to hold the wear plate 20 longitudinally with respect to the support plate 22, extending from the lower end 30 to the upper end 28.

[0063] Figure 3A shows a side view of the procedure for locking the wear plate 20 against the support plate 22 in the opposite longitudinal direction by using the lock plate 54. The lock plate 54 includes a protrusion 56 that is inserted into a complementary opening 58 of the wear plate 20. The lock plate 54 is inserted in the direction indicated by the arrow and holds pressure against the lower end 30 of the wear plate in the opposite longitudinal direction, ensuring that the wear plate abutment surface can contact the support plate abutment surface. The lock plate 54 is then spot welded to the support plate 22.

[0064] Figure 3B shows a perspective view of the procedure for locking the wear plate 20 to the support plate 22 in the opposite longitudinal direction. The protrusion 56 of the lock plate 54 has a tapered shape complementary to an opening (not visible) in the wear plate 20. Thus, the protrusion 56 and the opening 58 both assist in fixing the wear plate 20 in the longitudinal direction and centering the wear plate 20 on the support plate 22 when inserted as indicated by the arrow.

[0065] Figure 3C shows a second perspective view of the procedure for locking the wear plate 20 to the support plate 22, whereby the lock plate 54 moves as indicated by the arrow.

[0066] Figure 4A shows a side view of the wear assembly 16 fixed, engaged, and locked on the outer end 18 of the screw conveyor 12. The wear plate 20 is mechanically fixed to the support plate 22 and locked in place by the lock plate 54. The lock plate 54 is typically spot welded to the support plate 22. The wear assembly 16 is then welded to the screw conveyor 12 by a weld 60 where the outer end 18 of the helically formed metal screw conveyor intersects the support plate 22 and, on the opposite side of the outer end 18, at the intersection between the support plate 22 and the helically formed metal screw conveyor 12, and by a further weld 60 on the front face of the helically formed metal screw conveyor 12. It is preferred that MMA, TIG, or MAG welding can be used.

[0067] Figure 4B is a perspective view of the engaged and locked wear assembly 16 ready to be fixed to the end 18 of the screw conveyor.

[0068] Figure 4C is a second perspective view of the engaged and locked wear assembly 16 ready to be fixed to the end 18 of the screw conveyor.

[0069] FIG. 5 shows a perspective view of the wear assembly 16' in a disengaged and unlocked state. This locking plate 54 has an inclined end 50' which corresponds to the further inclined end 30' of the wear plate 20. The inclined ends contact to ensure a better mechanical connection between the wear plate 20, the support plate 22, and the locking plate 54'.

[0070] The procedure for engagement and locking is the same as in the previous embodiment. In the first step indicated by the rounded arrow, the support plate connection surface 48 engages with the wear plate connection surface 42, and in the second step indicated by the straight arrow, when the locking plate 54 is attached to the support plate 22, the support plate abutment surface 50' contacts the wear plate abutment surface 44.

[0071] FIG. 6 shows a perspective view of an alternative embodiment of the wear assembly 16' in a disengaged and unlocked state. In this embodiment, the protrusion 46' has a different shape with a wear plate abutment surface 44' located near the lower end 30. The wear plate abutment surface 44' is still parallel to the upper end 28 but is located along each wear plate connection surface 42'. The corresponding slot 52' has a corresponding different shape that defines a support plate abutment surface 50" along the support plate connection surface 48'.

Description of the Reference Numerals

[0072] 10 Decanter centrifuge 12 Spirally formed metal screw conveyor 14 Bowl, bowl wall 16 Wear assembly 16’ Wear assembly 18 Outer end 20 Wear plate 22 Support plate 24 Locking plate 26 Front surface of the wear plate 28 Upper end 30 Lower end 30’ Inclined end 32 side end 34 side end 36 wear indicator 38 rear surface of wear plate 40 front surface of support plate 42 wear plate connection surface 42’ wear plate connection surface 44 wear plate abutment surface 44’ wear plate abutment surface 46 protrusion, support plate connection surface 46’ protrusion 48 support plate connection surface 48’ support plate connection surface 50 support plate abutment surface 50’ inclined end, support plate abutment surface 52 slot 52’ slot 54 lock plate 54’ lock plate 56 protrusion 58 complementary opening 60 welding

Claims

1. A wear assembly for a metal screw conveyor formed in a spiral shape of a decanter centrifuge, a wear plate defining a wear plate front surface and a wear plate rear surface, wherein the wear plate rear surface defines a wear plate upper end portion, a wear plate lower end portion, and two opposed wear plate side end portions connecting the wear plate upper end portion and the wear plate lower end portion to each other, the wear plate rear surface further defines a longitudinal direction extending from the wear plate lower end portion to the wear plate upper end portion, the wear plate defines, on the wear plate rear surface, a wear plate connection surface extending substantially in the longitudinal direction and, on the wear plate rear surface, a wear plate abutment surface extending substantially parallel to the wear plate upper end portion, a wear plate; a support plate defining a support plate front surface and a support plate rear surface, wherein the support plate rear surface is attachable to the metal screw conveyor formed in the spiral shape, the support plate defines, on the support plate front surface, a support plate connection surface for engaging with the wear plate connection surface, the support plate further defines, on the support plate front surface, a support plate abutment surface for contacting the wear plate abutment surface when the support plate connection surface is engaged with the wear plate connection surface, a support plate; and a wear assembly comprising the same.

2. The wear assembly according to claim 1, wherein the support plate connection surface engages with the wear plate connection surface by a sliding operation between the wear plate rear surface and the support plate front surface in the longitudinal direction of the wear plate.

3. The wear assembly according to claim 1 or 2, wherein the support plate connection surface and the wear plate connection surface define a protrusion and a complementary-shaped slot into which the protrusion engages.

4. The wear assembly according to claim 3, wherein the protrusion is provided on the wear plate and the slot is formed in the support plate.

5. The wear assembly according to claim 3 or 4, wherein the protrusion has a cross-section of a double-tail.

6. The wear assembly according to any one of claims 3 to 5, wherein the protrusion and the slot taper in width in the longitudinal direction.

7. The wear assembly further includes a lock plate that can be attached to the support plate at the lower end of the wear plate to hold the wear plate against the support plate in a direction from the upper end of the wear plate to the lower end of the wear plate when the wear plate engages with the support plate. The wear assembly according to any one of claims 1 to 6.

8. The lock plate includes a protruding portion that protrudes into a complementary opening of the wear plate when the wear plate engages with the support plate. The wear assembly according to claim 7.

9. A rubber film is provided between the wear plate and the support plate, and the rubber film is preferably applied to the rear surface of the wear plate and / or the front surface of the support plate by spraying. The wear assembly according to any one of claims 1 to 8.

10. The support plate includes a wear indicator on the rear surface of the support plate. The wear assembly according to any one of claims 1 to 9.

11. The upper end of the wear plate is between 10 mm and 100 mm, preferably between 25 mm and 75 mm. The wear assembly according to any one of claims 1 to 10.

12. The support plate is made of a material softer than the wear plate. The wear plate is preferably made of carbide such as tungsten carbide, ceramic, polyurethane, or polyurea, and the support plate is preferably made of steel such as stainless steel. The wear assembly according to any one of claims 1 to 11.

13. A helically formed metal screw conveyor for a decanter centrifuge, comprising one or more wear assemblies according to any one of claims 1 to 12, wherein the rear surface of the support plate is attached to an end of the helically formed metal screw conveyor, and the longitudinal direction corresponds to a radially outward direction from the axis of the helically formed metal screw conveyor. A helically formed metal screw conveyor for a decanter centrifuge.

14. The worn assembly is attached to the helically formed metal screw conveyor of the decanter centrifuge according to claim 13 by a welded portion at the end of the helically formed metal screw conveyor.

15. A method of attaching a worn assembly to a helically formed metal screw conveyor for a decanter centrifuge, wherein the worn assembly is a wear plate defining a wear plate front surface and a wear plate rear surface, the wear plate rear surface defines a wear plate upper end portion, a wear plate lower end portion, and two opposed wear plate side end portions connecting the wear plate upper end portion and the wear plate lower end portion to each other, the wear plate rear surface further defines a longitudinal direction extending from the wear plate lower end portion to the wear plate upper end portion, the wear plate defines, on the wear plate rear surface, a wear plate connection surface extending substantially in the longitudinal direction and, on the wear plate rear surface, a wear plate contact surface extending substantially parallel to the wear plate upper end portion, a wear plate, a support plate defining a support plate front surface and a support plate rear surface, the support plate rear surface is attachable to the helically formed metal screw conveyor, the support plate defines a support plate connection surface on the support plate front surface, the support plate further defines a support plate contact surface on the support plate front surface, a support plate, and the method includes engaging the support plate connection surface with the wear plate connection surface, contacting the support plate contact surface with the wear plate contact surface, and a method including performing.

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