Patent Publication Number: US-2023149950-A1

Title: Centrifuges and related methods of use to dewater mature (fluid) fine tailings

Description:
TECHNICAL FIELD 
     This document relates to decanter centrifuges and related methods of use, for example to dewater mature fine tailings (MFT), also known as fluid fine tailings (FFT). 
     BACKGROUND 
     Decanter centrifuges such as the ALFA LAVAL™ LYNX 1000™ are used to dewater oil sands tailings. The LYNX 1000™ has a radial feed discharge, a conical beach, a cylindrical pond, and a solid flighting conveyor. 
     SUMMARY 
     Decanter centrifuges are disclosed, including accelerators and conveyor bodies for a decanter centrifuge. 
     A decanter centrifuge may comprise: a bowl forming a sedimentation chamber with a cake discharge and a centrate discharge; a screw conveyor within the sedimentation chamber, the screw conveyor having a conveyor body and a flight, the conveyor body defining a feed chamber; and an accelerator within the feed chamber for increasing the angular velocity of a feed mixture prior to entering the sedimentation chamber, the accelerator comprising an impeller with plural vanes, the plural vanes being releasably mounted to the conveyor body and sized to pass through an axial end of the conveyor body. 
     A method is also disclosed of operating and repairing a decanter centrifuge the method comprising: operating the decanter centrifuge to continuously process a feed mixture therein, the decanter centrifuge having a bowl and a screw conveyor, the bowl forming a sedimentation chamber with a cake discharge and a centrate discharge, the feed mixture comprising solids and liquids, operating comprising: supplying the feed mixture through a feed conduit into a feed chamber formed by a conveyor body of the screw conveyor; using an accelerator within the feed chamber to direct the feed mixture into the sedimentation chamber via radial ports in the conveyor body, the accelerator comprising an impeller with plural vanes; rotating the bowl and the conveyor body to effect at least a partial phase separation of the solids and liquids of the feed mixture; and discharging solids through the cake discharge, and discharging liquids through the centrate discharge; releasing the plural vanes from the conveyor body and passing the plural vanes out of an axial end of the conveyor body; installing a second set of plural vanes in the conveyor body by passing the second set of plural vanes through the axial end of the conveyor body, and mounting the second set of plural vanes to the conveyor body; and operating the decanter centrifuge to continuously process the feed mixture. 
     A decanter centrifuge is disclosed comprising: a bowl forming a sedimentation chamber with a cake discharge and a centrate discharge; a screw conveyor within the sedimentation chamber, the screw conveyor having a conveyor body and a flight, the conveyor body defining a feed chamber; and an accelerator within the feed chamber for increasing the angular velocity of a feed mixture prior to entering the sedimentation chamber, the accelerator comprising an impeller with plural vanes, in which the plural vanes are forwardly curved. 
     Decanter centrifuges are disclosed. In one case a decanter centrifuge is disclosed for the purpose of dewatering MFTs. The centrifuge may comprise an accelerator. The centrifuge may have an axial flow passage within conveyor flighting. The centrifuge may have redirection nozzles connected to the feed chamber, as a package for economically processing large volumes of MFTs. In some cases, only part of a decanter centrifuge is provided, for example an accelerator, or a conveyor body, with or without a bowl. 
     A decanter centrifuge is disclosed comprising: a bowl forming a sedimentation chamber with a cake discharge and a centrate discharge; a screw conveyor within the sedimentation chamber, the screw conveyor having a conveyor body and a flight, the conveyor body defining a feed chamber; a feed conduit connected to supply a feed mixture of solids and liquids to the feed chamber; a radial port in the conveyor body to direct the feed mixture from the feed chamber to the sedimentation chamber; and a flocculant conduit structured to supply a flocculant to the sedimentation chamber. 
     A method of operating a decanter centrifuge is disclosed the method comprising: supplying the feed mixture through a feed conduit into a feed chamber formed by a conveyor body of the screw conveyor; directing the feed mixture from the feed chamber into the sedimentation chamber through a radial port in the conveyor body; supplying a flocculant through a flocculant conduit into the sedimentation chamber; rotating the bowl and the conveyor body to effect at least a partial phase separation of the solids and liquids of the feed mixture; and discharging solids through the cake discharge, and discharging liquids through the centrate discharge. 
     A decanter centrifuge may be provided having a conveyor design with; 1) an inlet or feed chamber in which rotational energy may be applied to the feed slurry before the feed flows through the inlet apertures and discharges into the space between the conveyor body and the internal side of the bowl where the separation of the solid constituents is achieved, 2) a part that redirects the feed flow direction towards the liquid end hub as it discharges from the inlet into the space between the conveyor body and the bowl wall. And 3) window ports are cut into the flighting or the flighting is modified such that it is elevated on posts to provide a space for the redirected flow of the feed to travel unimpeded axially towards the liquid end hub between the conveyor tube body and the top of the flights. The feed flow is now travelling axially towards the liquid end hub with a relatively reduced velocity, a relatively reduced turbulence and a more laminar flow pattern. Such structure is expected to provide for relatively less turbulent flow than in a centrifuge such as the LYNX 1000™ that has solid flighting and no redirection nozzles. The stated structure is expected to allow for greatly improved settling of the suspended solids in the feed, and to minimize shear and hence reducing polymer / flocculant dosage and centrifuge rotating assembly maintenance requirements. 
     Redirection nozzles may be fastened, for example bolted, over inlets (feed zone discharge) to redirect the flow ninety degrees with respect to the feed zone from a radial direction to an axial flow direction in the sedimentation chamber towards the pond hub (clarification section) of the bowl. Such a configuration may reduce turbulence that would otherwise be caused by the influent being introduced radially from the feed zone and heading axially directly toward the bowl wall. Such is expected to eliminate or reduce wear occurring on the conical section. The caulk strips on the bowl extension may have a longer life as well. Conventional larger bowl machines such as the LYNX 1000™ incorporate solid flighting, axial feed ports into the sedimentation chamber, and limited to no means for increasing the angular velocity of the feed mixture prior to supply into the sedimentation chamber, and are used for municipal waste streams. By contrast, MFTs have been found to exhibit excessive wear on conventional centrifuges, thus requiring frequent servicing, decreased clarification, and increased polymer costs. 
     In various embodiments, there may be included any one or more of the following features. The plural vanes are formed on a disc part that has a maximum outer diameter smaller than a minimum inner diameter of the axial end of the conveyor body. The axial end of the conveyor body is a first axial end opposite an axial feed end of the conveyor body, the axial feed end comprising or defining a feed conduit into the feed chamber. The disc part is mounted to or forms an accelerator base. The disc part is adhered to the accelerator base. The disc part comprises: a ring part mounting the plural vanes; and a nose part centered within the accelerator base via a stem. The plural vanes are releasably mounted by fasteners that are accessible from an exterior of the conveyor body. The accelerator mounts within an outer collar body of the conveyor body. The fasteners extender through radial bores from an outer surface of the outer collar body to engage an outer surface of the accelerator. The fasteners comprise set screws. The fasteners engage a circumferential groove in the outer surface of the accelerator. The plural vanes are curved. The plural vanes are forwardly curved. The conveyor body is shaped to define or comprises a radial stop that forms an axial seat for the accelerator. A feed conduit connected to supply a feed mixture of solids and liquids to the feed chamber formed within the conveyor body; and radial feed redirection nozzles that are structured to direct the feed mixture from the feed chamber toward the flight along an outer surface of the conveyor body. The screw conveyor defines an axial flow passage between the conveyor body and a radially inward facing edge of the flight; and the feed redirection nozzles direct the feed mixture to the axial flow passage. The feed redirection nozzles are in communication with the feed chamber via respective radial ports in the outer surface of the conveyor body. Wear liners in the radial ports, the wear liners that form an axial seat for the accelerator. A feed zone liner within the feed chamber upstream of the accelerator. The feed zone liner comprises a ring part that defines an axial feed port to direct feed to the plural vanes of the accelerator. The ring part comprises guide fins arrayed about the axial feed port. The feed zone liner is releasably mounted to the conveyor body and sized to pass through an axial end of the conveyor body. The feed zone liner defines a maximum outer diameter smaller than a minimum inner diameter of the axial end of the conveyor body. The feed zone liner is releasably mounted by fasteners that are accessible from an exterior of the conveyor body. The feed zone liner mounts within an outer collar body of the conveyor body. The fasteners extender through radial bores from an outer surface of the outer collar body to engage an outer surface of the feed zone liner. The fasteners engage a circumferential groove in the outer surface of the feed zone liner. A flocculant conduit structured to supply a flocculant to the sedimentation chamber. An oil bath bearing assembly supporting one or more axial ends of the decanter centrifuge. The oil bath bearing assembly comprises a bearing that has a race and a roller element. The roller element comprises a spherical roller. The decanter centrifuge of claim  26  in which the bearing is a double-row spherical roller bearing. A pillow block supporting the bearing; and pillow block covers sealing first and second axial ends of the pillow block, in which interior surfaces of the pillow block covers and the pillow block define a bearing-receiving cavity in which the bearing and bearing fluid are disposed. A bearing fluid injector connected to a bearing fluid supply system. The bearing fluid injector comprises nozzles arranged at least partially circumferentially about an inner annular surface of one or both pillow block covers and oriented to direct bearing fluid toward an axial end of the bearing. The oil bath bearing assembly comprises one of more flinger rings adjacent one or more axial ends of the bearing and sloped with decreasing radius in a direction toward the bearing to direct bearing fluid toward the bearing. The conveyor body defines overflow ports to an outer surface of the conveyor body to increase the rate of solid discharge. The overflow ports are circular in cross section. The feed mixture comprising mature fine tailings produced from an oil sands process. Supplying the feed mixture from a tailings pond, in which the feed mixture comprises mature fine tailings produced from an oil sands process. Flocculating the feed mixture prior to supplying the feed mixture through the feed conduit. The nozzle is mounted over an outer surface of the conveyor body, with the nozzle communicating with the feed chamber via a port in the conveyor body. The nozzle defines a hood that forms an elbow-shaped flow passage that connects the port to an axially facing nozzle opening defined by the hood. An outer diameter of the redirection hood is smaller than an inner diameter of the flight. The cake discharge is at or near a first axial end of the bowl, the centrate discharge is at or near a second axial end of the bowl, and the nozzle is structured to direct the feed mixture toward the second axial end of the bowl. The axial flow passage defines an axial flow path that extends from the nozzle to the second axial end. The bowl comprises a conical beach section defining the first axial end and a cylindrical pond section defining the second axial end, and the flight forms a windowless helix whose inner edge is fused to the conveyor body continuously along a length of the flight throughout the beach section. Plural nozzles radially spaced around the feed chamber. The flight is helically mounted to an outer surface of the conveyor body via a plurality of radial posts such that the helical flight is radially spaced from the conveyor body to define the axial flow passage. A replaceable wear liner is internally mounted to the nozzle to protect the nozzle from abrasion from the feed mixture. The feed chamber is defined between axially spaced plates mounted within the conveyor body. An accelerator within the feed chamber for increasing the angular velocity of the feed mixture prior to entering the sedimentation chamber. The accelerator comprises an impellor with plural vanes. The feed conduit is connected to supply feed mixture to the feed chamber through a port in a first axial end wall of the feed chamber, and the impellor is fixed to a second axial end wall of the feed chamber. The nozzle, or a port that supplies the nozzle and is defined in the outer surface of the conveyor body, is located radially outward of the impellor in a plane, perpendicular to a centrifuge axis, defined by the impellor. The feed chamber comprises a plurality of lobes radially spaced from one another about the second axial end wall within the feed chamber to define a radial feed passage to the nozzle. The radial feed passage has side walls defined by the plurality of lobes and the side walls each mount a replaceable wear liner. A drive connected to simultaneously rotate the screw conveyor and the bowl at different angular velocities relative to one another. The feed mixture comprises mature fine tailings produced from an oil sands process. The feed mixture supplied to the feed chamber comprises a flocculant. The axial flow passage is defined by a plurality of axial windows in the flight. The mature fine tailings comprise solids of 10-45 % by weight of the feed mixture. Operating the decanter centrifuge to effect a phase separation of the solids and liquids in the feed mixture, and producing solids through the cake discharge, and liquids through the centrate discharge. Supplying the feed mixture from a tailings pond, in which the feed mixture comprises mature fine tailings produced from an oil sands process. The feed mixture prior is flocculated to supplying the feed mixture through the feed conduit. The decanter centrifuge is supported for rotation by oil bath bearings. A bowl forming a sedimentation chamber with a cake discharge and a centrate discharge; a screw conveyor within the sedimentation chamber, the screw conveyor having a conveyor body and a flight, the conveyor body defining a feed chamber; a feed conduit connected to supply a feed mixture of solids and liquids to the feed chamber; a radial port in the conveyor body to direct the feed mixture from the feed chamber to the sedimentation chamber; and a flocculant conduit structured to supply a flocculant to the sedimentation chamber. The feed conduit and an upstream portion of the flocculant conduit extend from an axial inlet end of the conveyor body and through an interior of the conveyor body. Axes of the feed conduit and the upstream portion of the flocculant conduit are oriented parallel with a central axis of the conveyor body. The feed conduit and the upstream portion of the flocculant conduit are coaxial with one another. The feed conduit is defined by a feed tube; and the upstream portion of the flocculant conduit is defined as an annulus defined between a flocculant tube and the feed tube. The flocculant conduit comprises radial ports in the conveyor body that are supplied by the upstream portion of the flocculant conduit. The flocculant conduit comprises a downstream portion that directs the flocculant toward the flight along an outer surface of the conveyor body. The downstream portion comprises a plurality of axial tubes along the outer surface of the conveyor body. The downstream portion extends along a beach section of the bowl to a flocculant outlet defined within a pond section of the bowl. Radial feed redirection nozzles are structured to direct the feed mixture from the feed chamber, through the radial ports in the conveyor body, and toward the flight along an outer surface of the conveyor body; and a flocculant outlet of the flocculant conduit is adjacent the feed redirection nozzles. An accelerator within the feed chamber for increasing the angular velocity of a feed mixture prior to entering the sedimentation chamber. The feed mixture comprising mature fine tailings produced from an oil sands process. To effect a phase separation of the solids and liquids in the feed mixture, and producing solids through the cake discharge, and liquids through the centrate discharge. 
     These and other aspects of the device and method are set out in the claims, which are incorporated here by reference. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which: 
         FIG.  1    is a perspective view of a conveyor for a decanter centrifuge. 
         FIG.  2    is a second perspective view of the conveyor of  FIG.  1   . 
         FIG.  3    is a cross-sectional view of a decanter centrifuge, which includes the conveyor of  FIG.  1   , and an outer bowl mounted over the conveyor, with the view taken central and parallel to the axis of the conveyor, and with lines used to illustrate the travel path of the liquid and solid mature fine tailings (MFT) in the decanter centrifuge. 
         FIG.  4    is a perspective view of an accelerator of the conveyor of  FIG.  1   . 
         FIG.  5    is a front end view of the accelerator of  FIG.  4   . 
         FIG.  6    is a side elevation view of a feed zone liner and accelerator combination from the conveyor of  FIG.  1   , with the position of fasteners shown. 
         FIG.  6 A  is a perspective close up of the accelerator and feed zone liner portion of the view of  FIG.  3   . 
         FIG.  7 A  is a front end view of the combination of  FIG.  6   , viewed from the  7 A- 7 A lines of  FIG.  3   , illustrating primarily the feed zone liner. 
         FIG.  7 B  is a rear end view of the combination of the conveyor of  FIG.  6   , viewed from the  7 B- 7 B lines of  FIG.  3   , illustrating primarily the accelerator. 
         FIG.  8 A 1    is a section view taken along the  8 A- 8 A section lines in  FIG.  3   . 
         FIG.  8 A 2    is a perspective view of the portion of the centrifuge as shown in  FIG.  8 A 1   . 
         FIG.  8 B 1    is a section view taken along the  8 B- 8 B section lines in  FIG.  3   . 
         FIG.  8 B 2    is a perspective view of the portion of the centrifuge as shown in  FIG.  8 B 1   . 
         FIG.  9 A 1    is a section view taken along the  9 A- 9 A section lines in  FIG.  3   . 
         FIG.  9 A 2    is a perspective view of the portion of the centrifuge as shown in  FIG.  9 A 1   . 
         FIG.  9 B 1    is a section view taken along the  9 B- 9 B section lines in  FIG.  3   . 
         FIG.  9 B 2    is a perspective view of the portion of the centrifuge as shown in  FIG.  9 B 1   . 
         FIG.  10 A 1    is a section view taken along the  10 A- 10 A section lines in  FIG.  3   . 
         FIG.  10 A 2    is a perspective view of the portion of the centrifuge as shown in  FIG.  10 A . 
         FIG.  11    is an exploded view of the accelerator of  FIG.  4   , with only the ring part in section. 
         FIG.  12    is a cross-sectional view of a conveyor and bowl for a decanter centrifuge, illustrating the operation of a flocculant conduit to the sedimentation chamber. 
         FIG.  12 A  is a close up view of the circular area denoted by dashed lines in  FIG.  12   . 
         FIG.  13    is a cross-sectional view of an oil bath bearing system of a decanter centrifuge. 
     
    
    
     DETAILED DESCRIPTION 
     Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims. 
     Oil sands may comprise water-wet sand grains held together by a matrix of viscous heavy oil or bitumen. The oil sands may comprise a mixture that is approximately 10% bitumen, 80% sand, and 10% fine tailings. Bitumen is a complex and viscous mixture of large or heavy hydrocarbon molecules, which may contain a significant amount of sulfur, nitrogen and oxygen. The extraction of bitumen from sand using hot water processes yields large volumes of fine tailings composed of fine silts, clays, residual bitumen and water. Fines in such mixtures include clay mineral suspensions or emulsions, predominantly kaolinite and illite. 
     An example fine tailings suspension has 85% water and 15% fine particles by mass. Dewatering of fine tailings occurs very slowly by gravity settling. When first discharged in ponds, the very low-density material is referred to as thin fine tailings. Oil sands tailings ponds are engineered dam and dyke systems that contain a mixture of salts, suspended solids and other dissolvable chemical compounds such as acids, benzene, hydrocarbons, residual bitumen, fine silts and water. The Syncrude Tailings Dam or Mildred Lake Settling Basin is a tailings pond that was, by volume of construction material, the largest earth structure in the world in 2001. 
     After a few years when the fine tailings have reached a solids content of about 30-35%, they are referred to as fluid or mature fine tailings (MFTs), which behave as a fluid-like colloidal material. The fact that MFTs behave as a fluid and have very slow consolidation rates at 1 g significantly limits options to reclaim tailings ponds. In fact, fine tailings will likely never fully settle in these tailing ponds. It is believed that the electrostatic interactions between the suspended particles, which are still partly contaminated with hydrocarbons, prevent settling from occurring. These tailing ponds have become an environmental liability for the companies responsible. A challenge facing the industry remains the removal of water from the fluid fine tailings to strengthen the deposits so that they can be reclaimed and no longer require containment. Many studies and project have been undertaken to address tailings pond remediation. 
     Tailings deposited in a tailings pond may contain primarily water, hydrocarbons and solids, which may include mineral material, such as rock, sand, silt and clay. The process described in this document may be useful in reclaiming these ponds by separating the liquid portion from the solid tailings, and using the separated portions to return land to its natural state. However, the apparatus and method may also be applied to any fluid having components to be separated, such as a sewage or solid-liquid mixture. The fluid to be treated may comprise tailings from deep within a tailings pond, without dilution, so long as the tailings are pumpable. If the tailings are not pumpable, they may be made pumpable by dilution with water. 
     Decanter centrifuges are used in the mechanical separation process of MFTs from the water in which the tailings are suspended. A centrifuge is a device that employs a high rotational speed to separate components of different densities. A decanter centrifuge separates solid materials from liquids in a slurry. The operating principle of a decanter centrifuge is based on separation via buoyancy. Naturally, a component with a higher density will fall to the bottom of a mixture, while the less dense component will be suspended above it. A decanter centrifuge increases the rate of settling through the use of continuous rotation, producing relatively high g-forces, for example forces equivalent to between 1000 to 4000 g-forces. Such acceleration reduces the settling time of the components by a large magnitude, for example permitting a mixture to settle in seconds in contrast to the same mixture settling in hours, days, years, or longer under ambient g-forces. 
     Through the use of decanter centrifuges, settling may be accelerated by flocculating the MFT clay particles, for example using polyacrylamides, and exposing the flocculated feed mixture to relatively high g-force in a decanter centrifuge, such as 120B0 g or higher, to effect phase separation. In such centrifuges, data suggests that the tailings feed creates internal turbulence along the length of the bowl resulting in lessened separation efficiency, increased solids caking along the pond section of the bowl, liquid influx into the beach section of the bowl, and increased wear etching and damage likely from the abrasive sand in such mixtures. 
     Referring to  FIG.  3   , a decanter centrifuge  10  is illustrated, having a screw conveyor  14 . The decanter centrifuge  10  may have a plurality of parts such as a screw conveyor  14  and an accelerator  80 . In some cases, the centrifuge  10  has a bowl  12 . The bowl  12  may in use encapsulate the decanter centrifuge  10  to house and protect the internal centrifuge parts. The screw conveyor  14  may in use be arranged in use within the sedimentation chamber  33 , and may include a conveyor body  50  and a flight  60 . A feed conduit  30  may be present or defined in the centrifuge  10 . Referring to  FIG.  3   , bowl  12  may form a sedimentation chamber  33  with a cake discharge port  24  and a centrate discharge port  26 . The screw conveyor  14  may be a part that conveys solid material to move towards the cake discharge port  24 . The conveyor  14  may have a conveyor body  50 , for example a central hub coaxial with the bowl  12  as shown in  FIG.  3   . The conveyor  14  may have a suitable conveying part, such as a scroll, auger, or helical flight  60 . The flight  60  may be helically mounted to an outer surface of the conveyor body  50 . The feed conduit  30  may be connected to supply a feed mixture of solids and liquids, for example a feed mixture of MFT, into the sedimentation chamber  33 . During use, feed mixture is continually supplied to the sedimentation chamber  33  while the bowl  12  and screw conveyor  14  are rotated. Rotation imparts a centripetal settling force upon feed mixture within the sedimentation chamber  33  to effect at least a partial phase separation between the liquids and solids in the feed mixture. The bowl  12  and conveyor  14  may rotate within a suitable housing  11 , and may be driven by a suitable means such as a motor with gearbox (not shown). 
     Referring to  FIG.  3   , bowl  12  and conveyor  14  may be oriented for co-current or counter-current flow, the latter of which is shown. The bowl  12  may be divided into a pond section  37 , which may be a straight cylinder, and a beach section  35 , which may have a conical shape, for example the shape of a truncated cone. The sedimentation chamber  33  may be defined by an internal encircling wall  32  of bowl  12 , a first end plate  34 A at a first axial end  34  of rotatably j ournaled drum or bowl  12 , a second end plate  36 A at a second axial end  36  of the pond section  37  of the bowl  12 . Where a conveyor body  50  is present, the sedimentation chamber  33  may be defined by the space between the outer surface of the conveyor body  50  and the internal encircling wall  32  of the bowl  12 . 
     Referring to  FIG.  3   , in a counter-current model as shown, the cake discharge port  24  is at or near first axial end  34 , while the centrate discharge port  26  is at or near second axial end  36 . The centrate discharge port  26  may be radially spaced about an axis of rotation  38 . Ports  26  may be positioned to open, and hence drain liquid from, a radius  39 , defined from axis  38 , selected to achieve a specific pond depth  109 , defined as radial distance from internal encircling wall  32 , within the bowl  12 . The selection of the pond depth  109  means the ports  26  act as a weir that takes off a top layer of liquid from fluids in the bowl  12 . The cake discharge port  24  may be defined by the spaces between the axial projections in a ring plate  34 A, for example a steel inner. The ring plate  34 A may be mounted via fasteners (not shown in Figures) to an axial end  34  of the beach section  35 . 
     Referring to  FIGS.  1 - 3   , the screw conveyor  14  may be structured to permit axial flow of fluids in the sedimentation chamber  33 . Referring to  FIG.  3    and  FIGS.  9 A 1 ,  9 A 2 ,  10 A 1 ,  10 A 2   , a feed redirection nozzle or plurality of nozzles  98  (for example distributed about axis  38 ) may be provided to direct feed mixture, entering the sedimentation chamber  33  from the feed conduit  30 , in an axial direction, for example towards axial end  36  and/or toward the axial flow passage  65 . Referring to  FIG.  3    and  FIGS.  9 A 1 ,  9 A 2 ,  10 A 1 ,  10 A 2   , a feed redirection nozzle or plurality of nozzles  98  may be provided to direct feed mixture, entering the sedimentation chamber  33  from the feed conduit  30 , in an axial direction, for example towards axial end  36  and/or toward the axial flow passage  65 . Referring to  FIG.  3   , feed conduit  30  may be connected to supply the feed mixture to a feed zone or chamber  76 , which may be formed within the conveyor body  50 . The feed conduit  30  may be a suitable supply conduit, such as a non-rotating pipe extended within and coaxial with a rotating internal cylindrical shell  31  formed by the conveyor body  50 . In some cases, the feed conduit  30  is mounted to rotate. In some cases, the feed conduit  30  is mounted to rifle the feed mixture as it passes through the conduit  30 . Each nozzle  98  may be structured to receive feed mixture from the feed chamber  76  via a respective port, such as a radial port  90 , in the outer surface  50 E of the conveyor body  50 , for example in between adjacent rows of flighting  60  as shown. Referring to  FIG.  9 A 1   , the plural nozzles  98  may be radially spaced about an outer circumference of the conveyor body, for example equidistant from one another to provide a balanced influx of feed mixture, around the feed chamber  76 , for example around the conveyor body  50 . 
     Referring to  FIGS.  3 - 5   , an accelerator  80 , such as an impellor, may be provided within the feed chamber  76  for rifling and/or increasing the angular velocity of the feed mixture prior to entering the sedimentation chamber  33 . The accelerator  80  may extend from a leading axial end  80 A to a base axial end  80 B. An accelerator  80  may have plural fins or vanes  84 , for example formed as a series of flat or curved plates as shown originating at or near or otherwise oriented to extend away from a common point coaxial with the rotational axis  38  of the centrifuge  10 . Data suggests that while processing MFT with a traditional decanter centrifuge lacking an accelerator, the feed enters the chamber  33  at a relatively low angular velocity relative to that of materials in the chamber  33 , and receives a significant excess amount of energy, resulting in turbulent flow. Such turbulence may be large enough to shear flocculating polymers, reducing polymer size and requiring relatively large amounts of flocculant to achieve the desired agglomerating effect. When an accelerator is used, the incoming feed mixture causes relatively less turbulence, and hence polymer shearing, despite the fact that the incoming feed may not have attained the same angular velocity as the conveyor  14  (in some cases 80% of the bowl  12  speed is achieved). In addition, the comparatively long path of flow in the thick liquid layer adjacent the nozzle  98  may permit excess energy to be dissipated in a manner as to prevent or reduce the occurrence of turbulent flows from liquids moving in a helical fashion around flight  60  to the centrate discharge. 
     Referring to  FIGS.  1  -  3  and  6 A , the accelerator  80  may have various characteristics and perform various functions. The conveyor body  50  may define the feed chamber  76 , through which the feed mixture may pass through. The accelerator  80  may be contained within the feed chamber  76 . The accelerator  80  may function to redirect feed mixture from axial to radial flow, and increase the angular velocity of a feed mixture prior to entering the sedimentation chamber  33 . The accelerator may comprise an impeller with plural vanes  84 . Referring to  FIG.  3   , the nozzle  98 , or a port  90  that supplies the nozzle  98  and is defined in the outer surface  50 E of the conveyor body  50 , may be located radially outward of the impeller  80  in a plane, perpendicular to a centrifuge axis  38 , defined by the impeller  80 . The feed mixture may enter the feed chamber  76 , change from an axial to a radial direction under acceleration by accelerator  80 , and exit the feed chamber  76 . Such a configuration may cause less turbulence and wear than a configuration where the feed enters the chamber moving in a first axial direction and is forced to change to a second axial direction opposite the first axial direction prior to discharge from the feed zone into the sedimentation chamber, or vice versa. 
     Referring to  FIG.  3   , the decanter centrifuge  10  may operate to process feed mixture in a suitable fashion. The feed mixture may initially be supplied into the feed conduit  30 , for example via a feed inlet  22 . The feed mixture, which may comprise a mix of solids and liquids, may continuously pass through the centrifuge  10  in use, for example by supplying (drawing, pumping, or by other means) the feed mixture from a tailings pond or other source. The feed mixture from a tailings pond may comprise mature fine tailings (MFT) produced from an oil sands process. The feed mixture, such as an MFT slurry, may be flocculated prior to supplying the feed mixture through the feed conduit, such as the feed inlet  22 . Flocculation of the feed mixture, for example using polyacrylamides, may accelerate the settling in the centrifuge  10  and may affect phase separation. The supplication of feed mixture into the centrifuge  10  may affect the operation of the centrifuge  10  to separate the solids and liquids in a slurry or feed mixture. 
     Referring to  FIG.  3   , following the travel path of the feed mixture, the decanter centrifuge  10  may have a suitable method of operation to separate phases of a feed mixture. The decanter centrifuge  10  may operate to continuously process a feed mixture. The feed mixture may pass through the feed inlet  22  and may enter the feed chamber  76 , which may be defined by a segment, such as portion or chamber  76 , in the conveyor body  50  of the screw conveyor  14 . The feed mixture may then be directed against the accelerator  80  within the feed chamber  76 . The feed mixture may be sent into the sedimentation chamber  33  via radial ports  90  in the conveyor body  50 . The accelerator  80  may have an impeller with plural vanes  84  through which the feed mixture may be propelled from the feed chamber  76  towards the radial ports  90  to be sent to the sedimentation chamber  33 . The feed mixture in the sedimentation chamber  33  may start to have a partial phase separation of the solids and liquids of the feed mixture as the bowl  12  and conveyer body  50  rotates. The rotation of the bowl  12  and the conveyer body  50  may exert centrifugal force and may partially separate the feed mixture into solids and liquids. The different densities of the solid and liquid elements in the feed mixture may allow the separation of materials in a slurry. The centrifugal force may allow a mixture with heavier density to travel through the centrifuge  10  and be directed towards the outermost layer of the bowl  12 , for example following the solid travel path in  FIG.  3   . The centrifugal force may also allow a mixture with lighter density to travel through the centrifuge  10  and be directed closest to the conveyor body  50 , for example following the liquid travel path in  FIG.  3   . The separated elements may be directed to exit the centrifuge, where the solid elements may be discharged through the cake discharge port  24  and the liquid elements may be discharged through the centrate discharge port  26 . The decanter centrifuge  10  may have a suitable method of operation for phase separation of a feed mixture. 
     Referring to  FIGS.  3  -  5   , the plural vanes  84  of accelerator may be structured for convenient replacement. Traditionally, replacement of the accelerator  80  warrants disassembly and rebuild of the conveyor body  50 , which may be an expensive, time-consuming process, and may lead to significant downtime where the machine is not operating to achieve separation. In one example one or more parts of the accelerator  80 , such as the plural vanes  84 , are releasably mounted to the conveyor body  50 . The plural vanes  84  of accelerator may be structured for convenient replacement. 
     Referring to  FIGS.  3  -  5   , the vanes  84  may be configured to be replaced out of one of the open axial ends of the conveyor body  50 . The plural vanes  84 , may be sized to pass through an axial end, such as first axial end  50 C, of the conveyor body  50 . Referring to  FIG.  3   , the decanter centrifuge  10  may facilitate a suitable method of repair for replacing the vanes  84  of the accelerator  80 . The feed mixture that passes through the centrifuge  10  may go through the accelerator  80 , which may cause the vanes  84  to wear over time. Worn vanes  84  may direct the feed mixture into the sedimentation chamber  33  with relatively less efficiency than unworn vanes, leading to inefficient or unsatisfactory separation of solid and liquid elements in the feed mixture. The accelerator vanes  84  may be replaced in a suitable fashion. Referring to  FIGS.  4 - 6 ,  6 A, and  8 A 1   , in an example method, the vanes  84  may be releasable from the conveyor body  50 , for example by loosening fasteners  144 . Referring to  FIGS.  3 - 5   , the plural vanes  84  may be passed out of an axial end, such as end  50 C or  44 , of the conveyor body  50  to remove the vanes  84  from the centrifuge  10 . Once removed, a second or new set of plural vanes  84  may be installed in the conveyor body  50 , for example by passing the new set of plural vanes  84  through the axial end, such as end  50 C or  44 , of the conveyor body  50 . The second set of plural vanes  84  to the conveyor body  50 . Once repaired, or refurbished or retrofitted, the decanter centrifuge may be operated to once more continuously process the feed mixture. 
     Referring to  FIGS.  4 - 6 ,  6 A and  8 A 1   , the vanes  84  may be formed on a disc part  87 . For example, the vanes  84  may be arrayed and spaced at different angular positions about an axis of rotation  38 , for further example, radially spaced to originate a non-zero distance from the axis  38 . The disc part  87  may comprise a ring part  122  and a nose part  120 . The nose part  120  may define a leading point of the accelerator  80 , which may be the first part of the accelerator  80  that comes in contact with and directs the feed mixture as the feed mixture enters the centrifuge  10  from the feed inlet  22 . The ring part  122  of the nose part  120  may mount the plural vanes  84  The ring part  122  may define a leading face  122 C and a base face  122 B, which face and face away from, respectively, the incoming feed in use. The vanes  84  may be mounted on face  122 C. The ring part  122  may have an axial opening  122 A, for example defined by a cylindrical stem  122 D. Opening  122 A may be structured to receive and mount a corresponding stem  120 A of nose part  120 . In the example shown the nose part  120  is centered coaxial with axis  38 , as is opening  122 A to receive and align the nose part  120 . The ring part  122  may form a perimeter rim  122 E, on one or both of faces  122 B and  122 C, for example on base face  122 B as shown. The ring part  122  may form a collar that encircles a base of the nose part  120 , for example to mount the nose part  120  in the ring part  122 . Each vane  84  may be formed, for example integrally, on the disc part  87 , or may be mounted to the ring part  122 , for example mounted releasably to allow a ring part  122  to be repaired by replacing one or more worn vanes  84 . 
     Referring to  FIGS.  4 - 6 ,  6 A and  8 A 1   , the disc part  87  may be mounted on or form part of an accelerator base  88 . The accelerator base  88  may have a disc shape or part as shown. A disc shape includes a part that spans or otherwise blocks the cross-sectional space defined within the cylindrical interior or bore of the conveyor body  50 , and includes a plate structure, a ring with a plug in the bore thereof, or any functional equivalent of the foregoing. The plural vanes  84 , for example the ring part  120 , may be formed or mounted on a leading face of the accelerator base  88 . For example, as shown in  FIG.  4   , the plural vanes  84  may be mounted on top of the disc part  87  of the disc base  88 . The nose part  120  may be attached to the accelerator base  88 . The accelerator base  88  may define a leading face  88 E and a base face  88 G, which may face and face away from, respectively, the incoming feed in use. The ring part  120  and/or disc part  87  may be mounted on face  88 E. The base  88 , for example face  88 E of the base  88 , may define an axial opening and/or an axial receiver, such as a stem receiver  135 , for receiving, aligning, and mounting either or both the ring part  122  or nose part  120 . In the example, a stem receiver  135 B of receiver  135  is structured to receive the knob stem  120 A of the nose part  120 , for example to center the nose part  120  in the base  88 . an axial stem receiver, for example defined by a cylindrical stem  122 D. Receiver  135  may define a ring part receiver  135 A, for example to receive and mount a corresponding stem  122 D of ring part  122 . In the example shown the stem receiver  135  is centered coaxial with axis  38  to receive and align the nose part  120  and/or ring part  122 . The base  88  may form a perimeter rim  88 F, on one or both of faces  88 E and  88 G, for example on base face  88 G as shown. The base  88  may form a collar that defines a rear end chamber  88 B. A tool connector, such as a tool stem  88 C, may be defined in the rear face  88 G, to permit the base  88  to be manipulated by a tool, for example to remove or install the base  88  from face  88 G. The tool stem  88 C may define an appropriate tool connector  88 H, such as a hex bore as shown. 
     Referring to  FIGS.  4 - 6 ,  6 A and  8 A 1   , the base  88  may be structured to fit or receive one or both the disc part  87  and nose part  120 . For example, the base  88 , such as leading face  88 E, may have a shape, such as a curved frustoconical shape that matches with a shape, such as an inverse curved frustoconical shape, of the base face  122 B of ring part  122 . The base  88  may form a seat for the disc part  87 , for example the ring part  122 . The leading face  88 E of base  88  may define a perimeter rim  88 A that defines a circular groove in which the perimeter rim  122 E is structured to be fitted. One or more of base  88 , disc part  87 , and nose part  120  may be connected via a suitable mechanism, such as by adhering with adhesive. Other connection methods may be used, such as welding, molding, friction or interference fitting, and fasteners. In some cases, one or both of parts  87  and  120  are threaded directly into the base  88 . 
     Referring to  FIGS.  3  -  6 ,  6 A, and  11   , the nose part may have suitable features. The nose part  120 , for example knob  120 E may be centered within the accelerator base  88  and/or ring part  122 , with a tip  120 C of knob  120 E coaxial with the central axis  38 , of the centrifuge  10 , as shown in  FIG.  3   . The knob  120 E may have a suitable shape for directing fluids radially outward toward the vanes  84 . In the example the knob  120 E has a convex shape, for example a conical or curved conical shape, coaxial with axis  38 . Referring to  FIGS.  6 A and  11   , the nose part  122  may protrude axially beyond the reach of the plural vanes  84  in a leading direction facing into the incoming fluid flow. The nose part  120  may provide for better flow efficiency of the feed mixture through the accelerator  80 . The nose part  120  may be mounted to, for example centralized within, the accelerator base  88  via a stem  120 A. The stem  120 A of the nose part  120  may fit through the ring part  122  into a stem receiver  135  of the base  88 , for further example nose part receiver  135 B, which may be a bore structured to receive the stem  120 A. The nose part  120  may be structured to seat upon the ring part  122 , for example the nose part  120  may form a radial flange  120 D that rests upon a seat groove  122 F at a leading face of the perimeter rim  122 E circumferentially surrounding the axial opening  122 A. A cylindrical portion  120 F of a base side of the nose part  120  may be structured to be received by the axial opening  122 A of the ring part. 
     Referring to  FIGS.  3 ,  6 , and  6 A , the accelerator  80  may mount within an outer collar body  150  of the conveyor body  50 . The outer collar body  150  may have a generally cylindrical shape, for example extending from a leading axial end  150 C to a base end  150 D. The outer collar body  150  may mount one or both the accelerator  80  and a feed zone liner  160 . The collar body  150  may form part of the conveyor body  50 , for example an axial portion of the cylindrical part of the body  50 . The ends  150 C and  150 D may tie in, for example by threading or welding (for example at weld gaps  151 ), to the other parts of the conveyor body  50 . The collar body  150  may define an exterior surface  150 A and an interior bore or surface  150 B. The collar body  150  may mount the accelerator  80  within an accelerator mounting zone  150 E of the surface  150 B. The collar body  150  may mount the feed zone liner  160  within a feed zone liner mounting zone  150 G of the surface  150 B. The collar body  150 , for example interior surface  150 B, may form a seat such as accelerator mounting seat shoulder  150 F, to receive and seat the accelerator  80 , for example to engage a radial flange  88 D of accelerator  80 . Thus, the conveyor body  50  may be shaped to define or comprise a radial stop that forms an axial seat (shoulder  150 F) for the accelerator  80 . The collar body  150 , for example interior surface  150 B, may form a seat such as a feed zone liner mounting seat shoulder  150 H, to receive and seat the feed zone liner  160 . Thus, the conveyor body  50  may be shaped to define or comprise a radial stop that forms an axial seat (shoulder  150 H) for the feed zone liner  160 . The outer collar body  150  may define the radial feed ports  90  to the exterior surface  50 E of the conveyor body  50 . In other cases, the body  150  may be formed of plural parts secured together, although the example shown is a single machined part. One or more gaskets may be used to seal axially between the accelerator  80  and the conveyor body  50 , for example a groove  88 J may be provided in base  88  to receive an O-ring that engages interior surface  150 B of outer collar body  150  when the accelerator  80  is seated therein. One or more gaskets may be used to seal axially between the feed zone liner  160  and the conveyor body  50 , for example a groove  165 C may be provided in base  165  to receive an O-ring that engages interior surface  150 B of outer collar body  150  when the feed zone liner  160  is seated therein. 
     Referring to  FIGS.  3 ,  6  and  8 A 1  –  8 B 2   , the decanter centrifuge  10  may have a releasable fastening mechanism to allow installation, removal and replacement of the accelerator  80  or parts thereof without full disassembly of the centrifuge  10 . The plural vanes  84 , for example the entire accelerator  80  or part thereof, may be releasably mounted by fasteners  144  that are accessible from an exterior, such as surface  50 E, of the conveyor body  50 . The conveyor body  50 , for example outer collar body  150 , may be structured to receive fasteners  144  that secure the accelerator  80 . The fasteners  144  may extend through the radial bores  150 J that extend from an outer surface of the outer collar body  150 , to engage an outer surface  80 C of the accelerator  80 , for example of the accelerator base  88 . The fasteners  144  may engage a groove or grooves, such as a circumferential groove  88 M of the base  88 . In other cases, the fasteners  144  may engage corresponding bores (not shown) in the base  88  or disc part  87 . The fasteners  144  may comprise set screws, whose heads may be inset flush with or below the outer surface  50 E of the conveyor body  50 , and may or may not be capped. The fasteners  144  may reach and penetrate through the conveyor body  50  and into the accelerator  80 . Once the fasteners  144  are secured in groove  88 M, the accelerator  80  is held securely against axial movement within the conveyor body  50 . Once the fasteners  144  are withdrawn from engagement with the accelerator  80 , the accelerator  80  or part thereof may be axially withdrawn from within the conveyor body  50 . 
     Referring to  FIGS.  3  and  6   , the accelerator  80  or part thereof may be structured to be removable through an open axial end of the conveyor body  50 . For example, the plural vanes  84  may be formed on a disc part  87  that has a maximum outer diameter, for example diameter  87 A, that is smaller than a minimum inner diameter, for example diameter  50 D of the axial end  50 C of the conveyor body  50 . In the example shown, the entire accelerator  80  is structured to be axially withdrawn from the interior of the conveyor body  50 , for example by having a maximum outer diameter  88 N of the base  88  equivalent to the diameter  87 A. Once the fasteners  144  are disengaged with accelerator  80 , the accelerator  80  may be removed. In operation, the axial end  50 C will typically be sealed, for example via an axial end plate  36 A, and thus prior to removal or installation of accelerator  80 , any such plate  36 A or covering may need to be removed or opened from end  50 C. However, by structuring and securing the accelerator  80  as shown, the accelerator  80  is able to be installed, removed, or replaced without dismantling the conveyor body  50 . In other cases, only part of the accelerator  80  may be removable in such a fashion, for example if the ring part  122  were removable by removing fasteners  144  whereas the base  88  were not. 
     Referring to  FIGS.  3 ,  6 , and  6 A  the centrifuge  10  may comprise a feed zone liner  160 , for example for directing fluids efficiently to the accelerator  80 . The feed zone liner  160  may be located upstream of the accelerator  80 , for example within the feed chamber  76 . The feed zone liner  160  may be structured to encourage or produce laminar axial flow of the feed mixture prior to contact with the accelerator  80 . The feed zone liner  160  may define a leading end  160 A and a base end  160 B, with fluids traveling in use from end  160 A to end  160 B. The liner  160  may define an axial feed port  160 E, for example coaxial with axis  38 . The feed port  160 E may be defined by a nose, such as a conical or convex nose  160 G. Referring to  FIGS.  3 ,  6 ,  6 A,  7 A, and  8 B 1 / 8 B 2   , one or more guide baffles or fins  160 D may be arrayed at angular positions about an interior surface  160 C of the liner  160 . The guide fins  160 D may be arranged evenly around the axial feed port  160 E. Fins  160 D may narrow in the direction of flow. The feed zone liner  160  may direct the fluid towards the accelerator  80 , which may encourage laminar flow to ensure optimal operation of the accelerator  80 . The feed zone liner  160  may also function to direct excess fluid to overflow ports  77 A, in case the feed chamber may have an abundance of incoming feed mixture. In the event the accelerator  80  becomes overloaded, the excess feed mixture may exit through overflow ports  77 A. 
     Referring to  FIGS.  3 ,  6 , and  6 A , the nose may be part of a ring part that defines the axial feed port  160 E. The feed zone liner  160  may comprise a base  165 . The base  165  may define an exterior surface  165 A of the liner  160 . A leading radial flange  165 B or other suitable stop may be structured on surface  165 A to engage or seat upon a corresponding seat shoulder  150 H of outer collar body  150 . A collar part  165 D may be located at leading end  160 A of the liner  160 , for example to mount groove  165 C. 
     Referring to  FIGS.  1 ,  3 ,  6  and  8 B 1  -  8 B 2   , the decanter centrifuge  10  may have a releasable fastening mechanism to allow installation, removal and replacement of the feed zone liner  160  or parts thereof without full disassembly of the centrifuge  10 . The feed zone liner  160  or parts thereof may be releasably mounted by fasteners  144  that are accessible from an exterior, such as surface  50 E, of the conveyor body  50 . The conveyor body  50 , for example outer collar body  150 , may be structured to receive fasteners  144  that secure the feed zone line  160 . The fasteners  144  may extend through the radial bores  150 K that extend from an outer surface of the outer collar body  150 , to engage an outer surface  165 A of the feed zone liner  160 , for example of the feed zone liner base  165 . The fasteners  144  may engage a groove or grooves, such as a circumferential groove  165 F of the base  165 . In other cases, the fasteners  144  may engage corresponding bores (not shown) in the base  165  or liner  160 . The fasteners  144  may comprise set screws, whose heads may be inset flush with or below the outer surface  50 E of the conveyor body  50 , and may or may not be capped. The fasteners  144  may reach and penetrate through the conveyor body  50  and into the feed zone liner  160 . Once the fasteners  144  are secured in groove  165 F, the liner  160  is held securely against axial movement within the conveyor body  50 . Once the fasteners  144  are withdrawn from engagement with the liner  160 , the liner  160  or part thereof may be axially withdrawn from within the conveyor body  50 . 
     Referring to  FIGS.  3  and  6   , the feed zone liner  160  or part thereof may be structured to be removable through an open axial end of the conveyor body  50 . For example, the ring part or nose  160 G, or the liner  160  (for example base  165 ) as a whole may have a maximum outer diameter, for example diameter  160 F, that is smaller than a minimum inner diameter, for example diameter  50 D of the axial end  50 C of the conveyor body  50 . In the example shown, the entire liner  160  is structured to be axially withdrawn from the interior of the conveyor body  50 . Once the fasteners  144  are disengaged with liner  160 , the liner  160  may be removed. Prior to removal or installation of liner  160 , any such plate  36 A or covering may need to be removed or opened from end  50 C. In addition, the accelerator  80  may need to be removed. However, by structuring and securing the liner  160  as shown, the liner  160  is able to be installed, removed, or replaced without dismantling the conveyor body  50 . In other cases, only part of the liner  160  may be removable in such a fashion, for example if the nose were removable by removing fasteners  144  whereas the base  165  were not. 
     Referring to  FIGS.  3  -  6 ,  6 A, and  11   , the accelerator may act to efficiently redirect incoming feed mixture radially outward. The incoming feed mixture from the inlet  22  may be separated radially outward, in which the knob  120 E splits the flow, and the rotating vanes  84  of the accelerator  80  act to induce a vortex or other suitable rotating action on the feed mixture to bring the mixture up to a relatively higher angular velocity prior to sedimentation. By shaping the nose knob  120 E as a truncated cone whose pointed end or tip  120 C faces the feed conduit  30 , air occurring in the feed or having become entrained by the feed while flowing into the inlet  22  may be passed away along the periphery of the knob, thereby preventing an air cushion from occurring in the inlet  22  which may interfere with the intended flow. The baffle knob may protrude in a direction towards the inlet  22  pipe. Such a structure may provide for improved control of the inflowing feed when it changes from being an axial flow to being a radial flow by softening or reducing feed zone material acceleration. 
     Referring to  FIGS.  3  -  6 ,  6 A, and  11    the vanes  84  may be structured to direct feed mixture radially outward, for example toward radial feed ports  90  to the exterior of the conveyor body  50 . The vanes  84  may have substantially radial, elongate ribs, uniformly distributed at various angular positions around a periphery of the knob  120 E, for example in a crosshair configuration. Each vane  84  may be positioned with a respective end  84 E originating at or radially outward from a periphery of the knob  120 E. Each vane  84  may be curved. In the example shown, each vane  84  is structured such that a leading face  84 C is curved, for further example in a forward curve shape. In a forward curve pattern, the leading face  84 C of the vane  84  has a convex shape that directs fluid more tangentially outward than purely radially outward movement. A forward curve thus ejects feed mixture radially into nozzles  98  while still following a spiral or circumferential path in cooperation with the rotation of the conveyor body  50  itself. A larger momentum may thus be transferred to the liquid in the feed chamber  76  in case the free liquid surface approaches the periphery of the knob  120 E, because the rate of flow of the feed increases. By altering the shape of the vanes  84 , from rectilinear ribs to ribs that are curved around the projection following a helix, the flow may be directed more strongly towards the ports  90 , thereby obtaining an improved axial distribution of the feed. By altering the radial extension of the ribs, it may be possible to ensure that the free surface of the liquid may not approach such a small radius that the liquid back flows out of the feed chamber  76  into the overflow ports  77 A through the annulus defined between the outer wall of the feed conduit  30  and the axial bore of the plate  77 . 
     Referring to  FIGS.  3 - 6 ,  6 A,  9 A 1 - 9 A 2  and  9 B 1 - 9 B 2   , radial ports may be defined by the conveyor body  50 , and in some cases the accelerator  80  and/or feed zone line  160  as well. The conveyor body  50  may define one or more radial ports  90  in the outer surface  50 E of the body  50 . The feed redirection nozzles  98  may be in communication with the feed chamber  76  via the respective radial ports  90 . The accelerator  80 , for example the base  88 , may form posts  88 L, that define gaps  126  that each align with and define part of a respective radial port  90 . The feed zone liner  160 , for example the base  165 , may form posts  165 G, that define gaps  165 E that each align with and define part of a respective radial port  90 . In the example shown, both posts  88 L and  165 G thus cooperate to form part of ports  90 . 
     Referring to  FIGS.  3 ,  6 A,  9 A- 9 A 2   , and  FIG.  9 B 1 - 9 B 2   , one or more wear liners  116  may be present in the radial ports  90 . The wear liners  116  may form an axial seat for one or both the accelerator  80  and feed zone liner  160 . Referring to  FIG.  6 A , a perimeter rim  88 A or other part thereof may contact the liner  116  (for example exterior surface  116 A of liner  116 ) to form an axial seat that prevents the accelerator  80  from axially advancing within the conveyor body  50 . A perimeter rim  165 H other part thereof may contact the liner  116  to form an axial seat that prevents the liner  160  from axially withdrawing within the conveyor body  50 . The wear liner  116  may be replaceable. The wear liner  116  may be internally aligned to protect radial port  90  from abrasion from the accelerated feed mixture. Referring to  FIG.  3   , the feed conduit  30  may be connected to supply a feed mixture of solids and liquids to the feed chamber  76  formed within the conveyor body  50 . The feed mixture in the feed chamber  76  may pass through a radial port  90 . The radial port  90  may be the initial contact of the feed mixture from the accelerator  80 , which may have an accelerated force that may compromise the port  90 . Each wear liner  116  may conform to the shape of the interior wall surface of the radial port  90 . 
     Referring to  FIGS.  3  -  6   , the vanes  84  may, in isolation, be structured to increase the velocity of the feed mixture only part of the way up to the angular velocity of feed mixture in sedimentation chamber  33  ( FIG.  3   ). The ribs or vanes  84  may extend a radial distance  84 A from the axis of the accelerator  80  (as shown the impellor axis is coaxial with the bowl axis  38  so only the axis  38  is illustrated). The radial distance  84 A may be selected to be a portion, for example less than half, of the radial distance  84 B from the axis  38  to the conveyor body  50  surface  50 E. The vanes  84  may be radial ribs uniformly distributed along the periphery of the baffle knob  120 E. The ribs may extend along straight lines or helical lines or other suitable shapes. The vanes  84  may impart a sufficient rotation to the feed in the inlet with the view of obtaining a stable circulation flow in the inlet cavity. 
     Referring to  FIG.  1   , a method of operating and repairing a decanter centrifuge  10  may be carried out. The decanter centrifuge  10  may be operated to continuously process a feed mixture therein. The feed mixture may be supplied through a feed conduit  30  into feed chamber  76 . The feed mixture may be directed by an accelerator  80  within the feed chamber into the sedimentation chamber via radial ports  90  in the conveyor body  50 . The bowl  12  and the conveyor body  50  may be rotated to effect at least a partial phase separation of the solids and liquids of the feed mixture. Solids may be discharged through the cake discharge (port  24 ). Liquids may be discharged through the centrate discharge (port  26 ). The operation of the centrifuge  10  may be halted, for example when the vanes  84  become worn. The plural vanes  84  may be released from the conveyor body  50 . For example, fasteners  144  may be removed from groove  88 M to disengage the accelerator  80 . The vanes  84  may be passed out of an axial end  50 C of the conveyor body  50 . A second set of plural vanes  84  may be installed in the conveyor body  50  by passing the second set through the axial end  50 C. The second set may be mounted to the conveyor body  50  for example by inserting fasteners  144  through bores  150 J in the outer collar body  150  into groove  88 M. The decanter centrifuge  10  may again be operated to continuously process the feed mixture. The feed zone liner  160  may be replaced or removed via a similar method. 
     Referring to  FIGS.  1 - 3   , the screw conveyor  14  may be structured to permit axial flow of fluids in the sedimentation chamber  33 . In one case axial flow is permitted radially inward of (as shown), or axially through, flight  60 . An axial flow passage  65  may be defined between the conveyor body  50  and a radially inward facing edge  68 B of flight  60 , for example pond flight  60 B. The axial flow passage  65  may define axial flow passage or passages  65  that extend across the pond section  37 , for example from a feed inlet such as feed redirection nozzles  98 , to the second axial end  36  of bowl  12 . 
     Referring to  FIG.  3   , permitting axial flow may improve laminar flow of liquids in the chamber  33  and reduce turbulence and fluid velocity. With a solid flighting system, the liquid portion of the slurry must wind its way around the helix of flight  60  to reach centrate discharge port  26 . By contrast, data suggests that when MFT is processed using a solid helical flight  60  (not shown) in the pond section  37 , the liquid is forced to travel around the helical flow channel defined by the flight  60 , toward end  46 . Liquids passing around the helix create turbulence that tends to upset settling of the solids in the MFT, carrying such solids all the way up to the second axial end  36  of the pond in some cases. Turbulence may also reduce polymer (floc) size, decreasing settling efficiency and increasing the amount, and hence cost, of flocculant added. Thus, by permitting quasi or fully axial flow of liquids toward the centrate discharge port  26 , such turbulence is reduced, leading to solid drop out and settling along the pond section  37 , after which conveyor  14  then carries such solids towards the beach section  35 . 
     Referring to  FIG.  3   , in the example shown, axial flow of fluids may be achieved by mounting the helical flight  60  to an outer surface  50 E of the conveyor body  50  via a plurality of radial gussets, plates, or posts  62 . Thus, the helical flight  60  is radially spaced from the conveyor body  50  to define the axial flow passage or passages  65 . A stiffener part, such as a helical bar  72 , may be mounted to flight  60  to increase the rigidity of flight  60 . In some cases, the flight  60  may be mounted on an outer edge of a series of vanes  61  that extend parallel to axis  38  and are radially spaced about the conveyor body  50 . In further cases, windows (not shown) may be cut through the flight  60  to provide axial flow. The gaps  66  between posts  62 , conveyor body  50  and inner edge  68 B, or the use of windows in flight  60 , may permit quasi or fully axial laminar flow, for example from the feed inlet to the centrate discharge port  26 . 
     Referring to  FIG.  3   , centrifuge  10  may be used in a continuous process to affect a phase separation of a feed mixture. As above, feed mixture, such as including MFTs produced from an oil sands process, may be supplied through a feed conduit  30  into a feed chamber  76 . Nozzles  98  may be used to direct the feed mixture into the sedimentation chamber  33 , in which the nozzle directs the feed mixture toward an axial flow passage  65  defined between the conveyor body  50  and an inner edge  68 B of a conveyor flight  60 . The bowl  12  and conveyor body  50  may be rotated to affect at least a partial phase separation of the solids and liquids of the feed mixture. Solids may be discharged through the cake discharge port  24 , and liquids discharged through the centrate discharge port  26 . 
     Referring to  FIG.  3   , the axial flow feature described here is provided on the pond section  37  only in some cases. As shown, the flight  60 , for example the part  60 A of flight  60  that extends across the beach section  35 , may form a windowless helix (solid) that hugs the conveyor body  50 , for example by having inner edge  68 A of flight  60 A fused to the conveyor body  50  continuously along a length, for example the entire length as shown, throughout the beach section  35 . In such cases, axial surface flow of liquids is permitted only in pond section  37 , but not in beach section  35 . A baffle, such as a baffle ring or disc, may encircle the conveyor body  50  in the beach section  35  to act as a weir that blocks axial and helical travel of liquids toward first axial end  34 . 
     Referring to  FIGS.  3 ,  8 B 1 , and  8 B 2   , each nozzle  98  may be mounted over, in some cases integrally projected in a radial direction out of, an outer surface  50 E of the conveyor body  50 . Referring to  FIG.  8 B 2   , the nozzle  98  may define a hood  102 , for example that is positioned over the outer surface  50 E and forms an elbow-shaped flow passage  101  that extends from a radial base opening  90 A to an axially facing nozzle opening. Referring to  FIG.  3   , the radial base opening  90 A may be aligned with the radial port  90  in the conveyor body  50  in use. Thus, feed mixture passes into the nozzle  98 , changes direction, for example from radial to an axial direction, and exits the nozzle  98 , heading toward the second axial end  36  of the bowl  12 . 
     Referring to  FIG.  3   , with MFT applications, feed mixture supplied via radially directed ports  90  directly into the sedimentation chamber  33  (no nozzles  98 ), appears to create turbulence, upsetting settled solids passing from the pond to the beach, and in some cases leading to wear in the internal encircling wall  32  of the bowl  12 . By contrast, nozzles  98  redirect the feed mixture away from the bowl  12  wall  32  to initiate axial flow in feed supplied to the chamber  33 , and thus may reduce disruption to settled solids passing to the beach. The nozzles  98  shown supply feed mixture directly into the pond. Where axial flow passages  65  are defined by the flight  60  and used in combination with nozzles  98 , laminar flow may be further improved, and wear on the bowl  12  may be reduced as the jet of feed mixture supplied to the sedimentation chamber  33  passes into the pond, where the energy of the redirected jet is dissipated. Where the nozzles  98  are mounted to the conveyor body  50  and the passages  65  are axially aligned with the openings  100  in the nozzles  98 , the conveyor body  50 , nozzles  98 , and passages  65  rotate together and thus always remain in alignment, avoiding or reducing wear on adjacent posts  62  or sides of flight  60  if windows are used in flight  60 . 
     Referring to  FIG.  3   , an outer radius  107  of the redirection hood  102  may be smaller than an inner radius  64  of the flight  60 B. Therefore, the redirected fluids travel along axial paths that are radially inward of the flight  60 B towards the liquid end hub. In one case, a minimum or average radius  64  of the radially inward facing edge  68 B of the flight  60  may be greater than or commensurate with a maximum radius  107  of the discharge opening  100  in the hood  102 . Both embodiments may reduce or eliminate the effect of the incoming feed mixture jet causing wear on the flight  60 , by providing a reduced radial footprint for the nozzle  98 . In one design configuration the radius  107  is the maximum radial height of the hood  102  itself. In some cases, the distance of the radius  107  is less than or equal to half the radial distance or height  109  of the pond itself. The shorter the radial extension of the hood  102  into the sedimentation chamber  33 , the less negative effect, if any, of the hood  102  on settled solids being conveyed from the pond to the beach. 
     Referring to  FIGS.  1 - 3   , the nozzle  98  may have suitable parts. The hood structure of the nozzle  98  may be defined by spaced side walls, a rear wall, a top wall, which may or may not curved, slanted, or curved and slanted, in order to achieve a directional change in the internal flow passage  101 . The nozzle  98  may be mounted to the conveyor body by a suitable mechanism, for example fasteners such as bolts (not shown) passed through bolt holes into the conveyor body. A replaceable wear liner  114  may be positioned within the nozzle  98 . The liner  114  may or may not conform to the shape of some or all of the inner surfaces of the nozzle  98  that define the flow passage  101 . In the example shown the wear liner is a tungsten carbide insert that is divided into two identical halves, though other configurations and number of parts may be used. Wear liners  116  in this document may have similar characteristics as liners  114 . The wear liner  114  may also have a pair of spaced side walls, a rear wall, and a top wall. The wear liner  114  may be formed of a wear resistant material that acts as a sacrificial part that protects the nozzle  98  from fluid breakout, and that may be replaced periodically at a lesser expense than replacement of the entire nozzle  98 . 
     Referring to  FIG.  3   , the feed chamber  76  may be defined by a radially confining wall (conveyor body encircling surface  50 E), a first axial end wall, such as a plate  79 , and a second axial end wall, such as a plate  77 . The feed chamber  76  may receive feed mixture through a port  79 A in plate  79 , for example connected to feed conduit  30 . The accelerator  80  may be mounted, for example fixed, to the plate  77 . If fixed, accelerator  80  will rotate with conveyor body  50 , thus inducing vortex action within feed chamber  76  during use. 
     Referring to  FIG.  3   , the centrifuge may comprise overflow ports  77 A, through which excess or increased flow of feed mixture may pass and circulate through the conveyor body  50 . The conveyor body  50  may define the overflow ports  77 A to an outer surface  50 E of the conveyor body  50  to increase the rate of flow of solid discharge. The overflow ports  77 A may be located in the upper chamber of the conveyor body  50 , such as upstream of the feed zone liner  160 . The flow of the feed mixture may become overwhelming for the accelerator  80  and the radial ports  90 . The overflow ports  77 A may assist the abundance of incoming feed mixture by allowing the excess feed mixture to leak out of the conveyor body  50  and flow into the beach section  50 B of the conveyor body  50 . The feed mixture that overflowed to the beach section  50 B may later flow back into the conveyor body  50  through the same ports  77 A, in which the feed mixture may finally pass through the accelerator  80  and the radial ports  90 . The overflow ports  77 A may be circular in cross section to allow passage of the overflowed feed mixture through the ports  77 A. 
     Referring to  FIGS.  1  -  3   , various parts may be provided to operate the centrifuge  10 . For example, a drive, such as a motor and gearbox may be mounted to rotate the bowl  12  and conveyor  14 . The gearbox may connect to simultaneously rotate the journaled screw conveyor  14  and the bowl  12  at different angular velocities relative to one another, for example through respective drive shafts (not shown). By rotating the bowl  12  at a different speed, for example 1-100 rpm faster than the conveyor  14 , the conveyor  14  applies a relatively gentle conveying effect to move settled solids towards the cake discharge port  24 . In some cases, the drive comprises plural drive motors and gearboxes that each drive and support a respective one of the conveyor  14  or bowl  12 , for example if each drive were mounted on a respective axial end  34 ,  36 . One or both the first and second axial ends  34  and  36  may each be mounted to a respective bearing unit, such as an oil bath or grease bearing unit, and the bowl  12  and conveyor  14  may rotate around a common axis  38 . The centrifuge  10  may be mounted on a suitable structural frame, with or without a removable hood or casing  28 . 
     Feed mixture may be supplied to chamber  33  via feed conduit  30  by a suitable pumping mechanism, and in a continuous fashion. For example, feed conduit  30  may enter the centrifuge by passing through a bearing unit in one of the axial ends  34 ,  36 , and connecting to the internal feed box or chamber  76 . In some cases, the feed mixture may comprise mature fine tailings produced from an oil sands process, for example if the feed conduit  30  is connected to receive such a feed mixture. In the example shown, a pump draws MFT from a tailings pond, at a level sufficiently below the pond surface to access MFT. In other cases, other types of fluids from the tailings pond may be accessed. The MFT is pumped via line to feed conduit  30 . Other pre-centrifuge processing steps may be carried out, for example to heat or dilute the MFT by addition of water. 
     The feed mixture supplied to the feed chamber  76  may also comprise a suitable flocculant. In flocculation, a chemical is added to agglomerate particles, which may be destabilized by addition of a coagulant, into relatively large particles colloquially called flocs, whose relatively large molecular weight causes an increase in density and drop out from the liquid phase. Flocculants include relatively high molecular weight, water soluble organic polymers. A flocculant may be added from a suitable source, such as a tank, using machinery such as an addition pump and a mixer in some cases (not shown). 
     Phase separated materials, such as liquids and solids discharged from centrifuge  10 , may be subject to further processing or disposal as desired. For example, solids from cake discharge port  24  may be ejected onto a conveying device, which may transport same to a disposal area. Liquids removed from centrate discharge port  26  may be transported via a line to a suitable disposal site, such as the tailings pond where the feed mixture was taken from. Oil and water separation may be carried out on centrate to remove entrained bitumen. Connections and communication between parts may occur through intermediate components. Radial ports  90  may have a suitable position and shape, for example such may be spaced radially and axially from one another, in a helical fashion. Ports  90  may be circular, oval, or other suitable shapes. 
     There may be a close fit between an outer edge  71  of flight  60  and the bowl  12 , such as 1-2 mm or other distances. More than one flight  60  may be provided, for example a double helix. Flights  60 A and  60 B may be separate or connected flights. Bowl  12  speeds of 800 - 4000 rpm may be used or other suitable speeds. Conveyor flights  60  may have a suitable rake, such as a positive, negative, or neutral (as shown in  FIG.  3   ) rake. 
     A centerless conveyor may be used, for example without a central conveyor body  50 . Centrifuge  10  may be used in applications other than processing MFT from oil sands, such as processing tailings from a mining process. MFTs may comprise solids of 10-45 % by weight of the feed mixture, although other ranges may be used. A vertical or horizontal centrifuge may be used. A co-current or counter-current flow may be used. A solid bowl  12  may be used with a conical, cylindrical, and cylindrical-conical configuration. 
     The centrifuge  10  may be used to affect a liquid-gas-solid, liquid-liquid, gas-liquid separation, or other suitable arrangements. Nozzles  98  may impart a direction change of ninety degrees to the feed mixture. In some cases, the nozzles  98  may direct the feed mixture in an axial direction, which may be a vector with a dominant axial scalar component, and forming an angle with respect to axis  38  of less than forty-five degrees, for example less than ten degrees and in some cases zero degrees. The conveyor body  50  may be solid or hollow as shown. 
     The mouth of the inlet apertures (for example nozzles) may be located on a radius greater than the radius to the outlet openings, such that a peripheral area of the inlet outwardly defined by the radius to the inlet apertures is free of carriers, inwardly extending projections. Parts of the centrifuge  10  may be arranged to inherently balance the device, for example by uniformly distributing nozzles, feed passages, and other parts radially about the circumference of conveyor body  50 . Weight balance may be achieved by arranging components to have a center of gravity along axis  38  during use. The impellor, such as accelerator  80 , and the vanes  84  may be fastened to the accelerator base  88 , for example in a removable fashion to permit removal in case such was not needed with the particular feed mixture processed, or in order to replace a worn part. 
     Plates  34 A and  36 A ( FIG.  3   ) may each have an axial opening  44 ,  46 , respectively, for various purposes such as receiving the feed conduit  30  and/or mounting drive shafts or bearings. Beach section  50 B of conveyor body  50  may be shaped in a conical fashion to follow the shape of the beach section  35  of bowl  12 . In one embodiment the inlet pipe or feed conduit  30  may be repositioned, for example along the axis  38  to adjust the distance between the outlet of the feed conduit  30  and the knob  120 E or accelerator. Thus, the diameter of the feed jet at the baffle knob  120 E may be altered by displacement of the feed conduit, thereby making it possible to adapt the flow in the feed chamber  76  to the type of feed and/or the rate of flow thereof. The impeller, such as accelerator  80 , may be geared to rotate faster or slower than the rotation of conveyor body  50 . Flocculant may be added to the feed mixture before, during, or after (by injection into the sedimentation chamber) the feed mixture is supplied to the sedimentation chamber section. Radially spaced may refer to the fact that parts are spaced about a circumference of an object, whether the circumference is taken by a cross-section or is projected into a plane. 
     In a decanter centrifuge, there may be a violent shearing effect imparted on the incoming feed mixture as the mixture changes direction and begins to rotate with the internal contents of the centrifuge. Polymer flocculants include water-soluble polymers that can form flocs from individual small particles in a suspension by adsorbing on particles and causing destabilization through bridging or charge neutralization. Polymer flocculants may promote the separation of particles from water to clean water. In colloid chemistry, flocculation refers to the process by which fine particulates are caused to clump together into a floc. The floc may then float to the top of the liquid (creaming), settle to the bottom of the liquid (sedimentation), or be readily filtered from the liquid. In some cases, a sufficiently high enough amount of shear energy may damage or break the long carbon chains of the virgin polymer, which may reduce the effectiveness of the flocculant, for example by shortening the polymeric chains, and reducing the molecular weight of the flocculant. A reduction in molecular weight due to shearing action may be disadvantageous in that the flocculant may operate less effectively to remove solids, requiring the mixture to spend a relatively longer retention time in the pond section  37  of the centrifuge  10  in order to facilitate the same settling distance than would have been otherwise accomplished by a longer, higher molecular weight unsheared flocculant. Such an effect may be counterproductive to settling. 
     Referring to  FIGS.  12  and  12 A , the decanter centrifuge  10  may be structured to reduce or avoid shear effects on incoming flocculant. The centrifuge  10  may comprise a flocculant conduit  170  structured to supply a suitable flocculant, such as a polymer flocculant, to the sedimentation chamber  33 . A flocculant that is mixed with the feed mixture prior to, while, or shortly thereafter entering the centrifuge  10 , may begin to flocculate in the feed conduit  30  prior to being accelerated up to centrifugal separation rotation speed, and thus once accelerated, the relatively high shear forces induced by the rotating centrifuge may damage the flocculant, reducing the size of the polymeric matrix. By contrast, by supplying the flocculant, for example in a virgin state, into the sedimentation chamber  33 , and thus at least partially bypassing the feed conduit  30 , the negative effects of shear on the polymer may be relatively reduced, because the flocculant is accelerated prior to undergoing substantial flocculation with the feed mixture. 
     Referring to  FIGS.  12  and  12 A , the feed and flocculant may be supplied through one of the axial ends  34  of the conveyor body  50 . A feed inlet  22  may be defined at the axial end  34  for connecting with a feed line from a feed mixture source (such as a tank or tailings pond). The flocculant may enter the centrifuge  10 , for example the upstream portion  170 A, through an inlet  175  defined at the axial end  34 , for example the flocculant may be added to the annulus section of the polymizer feed tube assembly exterior to the centrifuge  10  at the inboard side of a feed tube mounting flange  176 . The feed conduit  30  and an upstream portion  170 A of the flocculant conduit  170  may extend from axial end  34  of the conveyor body  50  and through an interior of the conveyor body  50 . The mounting flange  176  or other suitable connector may be present at the axial end  34  for connecting one or both the feed conduit  30  and flocculant conduit to respective feed and flocculant sources. The feed conduit  30  and the upstream portion  170 A of the flocculant conduit  170  may be oriented parallel with a central axis  38  of the conveyor body  50 . An axis  30 A of the feed conduit  30  and an axis  170 B of the upstream portion  170 A of the flocculant conduit  170  may be coaxial with one another, for example if the conduits  30  and  170  are nested together as shown. One or both of the feed conduit  30  and the flocculant conduit  170  may be formed by respective tubes  31  and  173 . The upstream portion  170 A of the flocculant conduit  170  may be defined as an annulus between flocculant tube  173  and feed tube  31 . During use, feed mixture and flocculant are pumped through tube  31  and the annulus defined between tubes  31  and  173 , respectively, toward the feed chamber  76 . As will be explained, in the example shown, feed mixture may be supplied into the feed chamber, while flocculant at least partially bypasses the feed chamber  76 . 
     Referring to  FIGS.  12  and  12 A , the flocculant conduit  170  may be used to transfer flocculant to the sedimentation chamber  33  in a suitable fashion. Through the inlet  175  a flocculant solution may be pumped at a particular dosage rate to facilitate flocculating the product. The flocculant feed rate may be calculated at a specific weight of flocculant, for example kg/tonne, on a dry solids basis, which may be pre-determined by way of lab testing or other means. The outer column  173  may be shorter in length than the feed tube  31 . The flocculant may exit the annulus  172  through one or more radial passageways. In the example shown, the flocculant exits annulus  172  through a suitable number, for example eight radial holes  177  near or at an axial end of the outer flocculant feed tube  173  assembly. The flocculant may pool in a flocculant collection zone  179 , which may be an annulus defined between in an interior surface  50 G of the conveyor body  50  and an exterior surface of the conduit  170 . The flocculant collection zone  179  may have a sloped bottom, for example defined by interior surface  50 G of conveyor body  50 , for example sloped equal to the conical section angle of repose of a conveyance tube  171  to direct the flocculant. The feed zone end  170 C of the collection zone  179  may comprise a baffle wall. 
     Referring to  FIGS.  12  and  12 A , a downstream portion of the flocculant conduit  170  may direct flocculant from the flocculant collection zone  179  to the sedimentation chamber  33 . For example, the downstream portion may direct the flocculant toward the flight  60 . The flocculant conduit  170  may comprise radial ports  178  in the conveyor body  50  that are supplied by the upstream portion  170 A of the flocculant conduit  170 . The downstream portion may comprise a plurality of axial tubes, such as conveyance tubes  171 , that may direct the flocculant, for example supplied through ports  178 , toward the flight  60  along the outer surface  50 E of the conveyor body  50 . The radial ports  178  may define openings to the conveyance tubes  171 , which may form part of the flocculant conduit  170 . 
     Referring to  FIGS.  12  and  12 A , the downstream portion of the conduit  170  may feed flocculant to the sedimentation chamber  30  in a suitable fashion. The flocculant conveyance tubes  171  may extend along a beach section  35  of the bowl  12  to a flocculant outlet  171 A, for example a nozzle or plurality of nozzles, defined within the sedimentation chamber  33 . The flocculant conveyance tubes  171  may be angled at the same angle as the base, for example the outer surface  50 E, of the flocculant collection zone  179 . Due to the gravitational forces applied to the flocculant by the spinning of the rotating assembly, the flocculant solution may travel down the flocculant conveyance tubes  171 . The downstream portion may extend to the pond section  37  of the bowl  12 . The flocculant conduit  170  may allow the flocculant to bypass the feed chamber  76 . The conveyance tubes  171  may allow the flocculant to bypass and avoid interacting with the accelerator  80 , feed nozzles, and redirection shrouds, if present. In the illustration provided, flocculant travels along upstream portion  170 A, through the collection zone  179 , and through flocculant conveyance tubes  171  travel along the conveyor body  50 , towards the pond section  37 , in the direction indicated by arrows  174 . The flocculant outlet  171 A of the conveyance tube  171  may discharge the flocculant adjacent to, for example at or near, the feed redirection nozzles  98 . The addition of the flocculant adjacent to, for example in direction parallel to, the feed redirection nozzles  98  may allow the flocculant to avoid the high energy associated with the centrifugal acceleration action at the accelerator  80 . In some cases the flocculant may enter the sedimentation chamber upstream of a baffle  60 C of the flight  60 . 
     Referring to  FIGS.  12  and  12 A , adding flocculant in bypass of the feed chamber may be advantageous over adding flocculant to the feed chamber with the feed mixture. A bypass feature may allow for the flocculant to be added directly into the pond section  37  of the centrifuge  10 . The addition of the flocculant in such a manner may allow the flocculant to avoid centrifugal forces, which may otherwise result in shearing of the flocculant. A bypass feature may allow unsheared virgin flocculant direct access to the pond section  37  of the centrifuge  10  where it can interact with the suspended solids of the slurry and provide maximum settleability for the low specific gravity clay constituent of the feed slurry. This may provide for quicker settling and reduced flocculant usage to achieve the same results as adding flocculant to the product feed prior to the feed tube  22  in other applications. In the example shown, the feed mixture may be continuously processed within the centrifuge  10 , and the flocculant may be supplied through a feed conduit  170  into the sedimentation chamber  33 . In so doing the virgin polymer avoids the extremely high energy associated with the centrifugal acceleration action at the accelerator imparted to the incoming slurry. There is a high amount of shear imparted to the incoming slurry that may be counterproductive to the establishment and retention of long polymer carbon chains. This high amount of shear energy may otherwise damage or break the long carbon chains of the virgin polymer and shorten the chains thereby reducing the molecular weight of the floc. This bypass feature for the polymer may allow unsheared virgin polymer direct access to the decanter section of the RA where it can interact with the suspended solids of the slurry and provide maximum settleability for the low specific gravity clay constituent of the feed slurry. Such mayl provide for quicker settling and reduced polymer usage to achieve the same results as adding polymer to the product feed prior to the feed tube in other applications. 
     Referring to  FIG.  13   , an oil bath bearing assembly  192  may support one or more axial ends, such as ends  34  and/or  36  of the decanter centrifuge  10 . A bearing assembly may minimize the friction between the moving parts, reducing the wear on the parts and lowering operating temperatures. Using an oil bath bearing assembly  192  may be advantageous over other bearing systems, such as grease bearings, providing relatively lowered friction, lowered operating temperature, and longer life. An oil bath bearing assembly  192  may comprise a bearing  190 , which may include a race  190 C and a roller element  190 D, or in the example shown a plurality (for example two) sets of roller elements. The roller element may comprise any suitable roller element, such as a spherical roller. The bearing  190  may be any suitable bearing such as a double-row spherical roller bearing. A spherical roller bearing may be advantageous over other bearings, such as roller or thrust bearings, in that a roller bearing may be relatively more forgiving for misalignment issues. For example, a spherical roller bearing may permit several degrees of misalignment during operation, whereas a cylindrical or needle bearing may only permit up to a ¼ of a degree. With more tolerance, the bearing, and hence the centrifuge, may be relatively less expensive to manufacture and assemble, and relatively less expensive to operate. 
     Referring to  FIG.  13   , the oil bath bearing assembly  192  may have a variety of suitable parts and features. The bearing  190  may be supported by a pillow block  180 . One or more covers, such as an inboard pillow block cover  180 A and an outboard pillow cover block  180 B, may seal first and second axial ends  180 A- 1  and  180 B- 1 , respectively, of the pillow block  180 . Interior surfaces of the pillow block covers  180 A and  180 B and the pillow block  180  may define a bearing-receiving cavity  180 C. The bearing  190  and a suitable bearing fluid may be disposed within the cavity  180 C. The bearing fluid may be any suitable bearing fluid, such as a lubricating oil. The bearing  190  may be submerged within the bearing fluid contained within the cavity  180 C. 
     Referring to  FIG.  13   , the bearing fluid may be supplied and/or circulated throughout the oil bath bearing assembly  192  by a suitable mechanism. One or more bearing fluid injectors (not shown) may be used to inject the bearing fluid. The bearing fluid injectors may comprise nozzles. The injectors may be arranged in a suitable fashion within the assembly  192 , for example a series of injectors may be arrayed at least partially circumferentially about an inner annular surface  180 A- 2  and  180 B- 2  of one or both pillow block covers  180 A and  180 B, respectively. The injectors may be oriented to direct bearing fluid toward one or more axial ends, such as ends  190 A and  190 B, of the bearing  190 . A bearing fluid supply system may be provided to supply and/or return bearing fluid, for example similar to a hydraulic fluid system. The bearing fluid supply system may permit the circulation of the bearing fluid. The bearing fluid supply system may include multiple drains (not shown), which may return bearing fluid from the bearing assembly  192 . In some cases the drains may be located in pillow block  180 , for example passing fluid out of block  180  via a series of drains oriented radially through the block  180 , exiting an outer circumferential surface  180 D of the block  180 . During the circulation between the drains and the injector, the fluid may pass through a filter (not shown), ensuring that the fluid remains clean. The cleanliness of the fluid may extend the lifespan of the bearing  190 , and may reduce the operating temperature of the bearing  190 . 
     Referring to  FIG.  13   , the oil bath bearing assembly  192  may comprise one or more flinger rings, such as rings  188 A and  188 B, adjacent to one or more axial ends  190 A and  190 B, respectively, of the bearing  190 . The retention of the fluid within the cavity  180 C may be assisted by inboard flinger ring  188 A and outboard flinger ring  188 B. The flinger rings  188 A,  188 B may be structured to direct the fluid, such as oil, back towards the bearing  190 . The flinger rings  188 A and  188 B may be sloped with decreasing radius in a direction toward the bearing  190  to direct bearing fluid toward the bearing  190 . One or more flinger rings may keep the oil redirected to the bearing, for example to retain oil in the bearing at least one revolution before it drains out of the bottom of the pillow block cover. 
     Referring to  FIG.  13   , the bearing assembly  192  may be sealed by a suitable mechanism. The cavity  180 C may be sealed by a suitable seal to prevent the fluid from leaking. There may be an outboard and inboard seal present, to ensure that both axial ends of the cavity  180 C are sealed. The seals may be any suitable seal, such as an inboard labyrinth seal  186 A or an outboard labyrinth seal  186 B. The block  180 , covers  180 A,  180 B and the cavity  180 C, may be captured by a hub  184  and a lid  182  system. The hub  184  may be sealed by a suitable seal such as a hub seal  184 A. The lid  182  may be sealed by a suitable seal such as a lid seal  182 A. The hub  184  and lid  182  may allow the bearing  190  to be isolated from the processing material and process within the centrifuge  10 . The isolation of bearing  190  may allow the bearing  190  to remain cleaner than if the bearing  190  was not isolated. Ensuring that the bearing  190  is clean may allow for an increased life span of the bearing  190 , and a decreased temperature of the bearing during operation. The bearing assembly  192  may be pressurized, and the seals used may be rated for such operating pressures. 
     In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite articles “a” and “an” before a claim feature do not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims.