Patent Publication Number: US-2018036662-A1

Title: Separation apparatus

Description:
FIELD OF THE INVENTION 
     This invention concerns separation apparatus, and particularly rake classifier assemblies. 
     BACKGROUND OF THE INVENTION 
     Rake classifiers, are used in water treatment installations, as well as in mining and other applications where it is required to separate particulate solids from a liquid. Rake classifiers generally comprise an elongate rake member which is reciprocally moved upwardly from a start position along an inclined surface so as to urge solid material up the inclined surface. Then after a finish position has been reached, the rake member is returned to the start position but with the elongate rake member clear from the inclined surface until the start position is again reached. Rake classifiers are used for instance in water treatment plants to remove gravel, grit and/or other solids from the water. 
     Typically a rake classifier is provided in a channel leading off a main separating tank, with the water level maintained such that in use most of the elongate member is immersed in liquid, but the upper end in the finished position is above the liquid level. 
     Prior drive arrangements for the elongate rake member have tended to use relatively complex gear arrangements with an electric motor. Such arrangements are potentially expensive to manufacture and install, and will require periodic not insignificant maintenance. 
     With rake classifiers it is important to control the speed of the elongate rake member as it moves up the inclined surface. If the elongate rake member is moved too quickly, liquid being displaced can wash solids back down the inclined surface. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention there is provided a rake classifier assembly, the assembly including an elongate rake member reciprocally movable up an inclined surface to move solid material thereup, and a guide arrangement, the guide arrangement including a guide track along which a guide member connected to the elongate rake member is movable, the guide track being selectively movable between first and second alignments, with the guide track extending substantially parallel to the inclined surface in the first alignment such that the elongate rake member can be moved up the inclined surface moving solid materials thereup, and in the second alignment the guide track diverges downwardly away from the inclined surface, such that as the elongate rake member is moved downwardly the elongate rake member also moves away from the inclined surface. 
     Two guide arrangements may be provided, one towards an upper end of the elongate rake member, and another towards a lower end of the elongate rake member. 
     In the or each guide arrangement the guide track may be pivotally mounted to a frame so as to be pivotally movable between the first and second alignments, and the pivotal mounting may be provided at an upper end relative to the inclined surface, of the guide track. 
     The guide track may comprise a spaced pair of elongate guides, and the elongate guides may be in the form of inwardly facing channel section members. 
     A respective guide member connected to the elongate rake member may be engageable with each elongate guide. The or each guide member may include a wheel movable along the guide track, which wheel may have a rubberized outer surface. 
     A first linear actuator may be provided for moving the elongate rake member longitudinally relative to the inclined surface. The first linear actuator may be engageable between a frame which mounts the or each guide arrangement, and the elongate rake member. 
     The, each, or a one of the guide arrangements may include a second linear actuator for selectively moving the guide track between the first and second alignments. 
     The first and/or second linear actuators may be in the form of cylinders, which may be hydraulically or pneumatically controlled. Alternatively the first and/or second linear actuators may be in the form of linear motors. 
     Where two or more guide arrangements are provided, a one only of the guide arrangements may include a second linear actuator, and linkage means may be provided extending between the guide arrangement with a second linear actuator and the other guide arrangement or arrangements, to provide for equivalent movement of each guide arrangement. 
     The elongate rake member may include a plurality of spaced transverse members extendable across the inclined surface to move solid material thereup. 
     The elongate rake member may include a frame which mounts the spaced transverse members, and the or each guide member. 
     The rake classifier assembly may be computer controlled, and may be configured such that the elongate rake member can be moved at different speeds respectively up and down the inclined surface. The rake classifier assembly may be configured such that the elongate rake member can be paused at a maximum upward position of the inclined slope to allow liquid to drain back down the slope. 
     Sensors may be provided to detect the location of one or more of the movable components of the rake classifier assembly. 
     According to a second aspect of the invention there is provided a solid and liquid separation installation, the installation including a rake classifier assembly according to any of the preceding thirteen paragraphs. 
     The installation may include a main separation chamber with an outlet leading thereof to the inclined slope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: 
         FIG. 1  is a diagrammatic perspective view of a first rake classifier assembly according to the invention; 
         FIGS. 2-5  are diagrammatic side views of the assembly of  FIG. 1  respectively in first, second, third and fourth positions; 
         FIG. 6  is a diagrammatic perspective view of a solid and liquid separation installation according to the invention; 
         FIG. 7  is a diagrammatic plan view of the installation of  FIG. 6 ; 
         FIG. 8  is a diagrammatic cross-sectional view along the line A-A of  FIG. 7 ; and 
         FIG. 9  is a similar view to  FIG. 1  but of a second rake classifier assembly according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 to 8  of the drawings show a first rake classifier assembly  10  suitable for moving solids up an inclined surface  12  as shown in  FIGS. 6 to 8 . The assembly  10  includes an elongate rake member  14  which has a frame  16  with two sides, each side including a plurality of inclined members  18  interconnected to a plurality of upright members  20 . The frame  16  mounts a spaced pair of lower rails  22  in the form of outwardly facing channel section. Extending between and beneath the lower rails  22  are a plurality of spaced scraper members  24  in the form of lengths of downwardly facing angle iron. The uppermost  26  and lowermost  28  upright members  20  extend above the remainder of the upright members  20  and inclined members  18 . 
     The assembly  10  also comprises a rectangular frame  30  comprising two elongate outer members  32  and a plurality of cross-members  34 . The uppermost and lowermost upright members  26 ,  28  extend through and above the frame  30 . 
     A first hydraulic cylinder  36  extends to the right as shown in  FIGS. 1 to 5  from a one of the cross members  34  to engage with a cross member  38  extending between the uppermost upright members  26 . Operation of the first hydraulic cylinder  36  causes relative longitudinal movement between the elongate rake member  14  and frame  30 . 
     A pair of identical guide arrangements  40 ,  42  are mounted on top of the frame  30  with a first guide arrangement  40  provided at the upper right hand end of the frame  30 , and the second guide arrangement  42  provided at the lower left hand end of the frame  30 . Each guide arrangement  40 ,  42  comprises a pair of brackets  44  at the upper end which pivotally mount a spaced pair of elongate guides  46  in the form of a pair of inwardly facing lengths of channel section. The lower ends of the guides  46  are interconnected by a cross member  48 . Each elongate guide  46  rotatingly mounts a respective rubberized wheel  50  provided on the outer side at the top thereof on respectively the uppermost and lowermost upright members  26 ,  28 . 
     Also extending between the brackets  44 , and connected to the elongate guides  46  is an n-shaped bracket arrangement  52  with a central support  54 . A second hydraulic cylinder  56  extends between the cross piece of the end bracket arrangement  52  and a respective cross member  58  of the frame  30 , such that operation of the second hydraulic cylinder  56  provides for pivotal movement of the elongate guides  46  relative to the frame  30 . 
     The second hydraulic cylinders  56  may have a common hydraulic supply with a splitter provided for the supply to the respective cylinders  56 . 
       FIGS. 2 to 5  sequentially show operation of the rake classifier assembly  10 . In  FIG. 2  the assembly  10  is shown in a first starting position with the elongate rake member  14  at the lowermost position on the inclined surface  12 , with the elongate guides  46  inclined downwardly extending parallel to the inclined surface  12 . The wheels  50  are located at the lowermost (left hand) ends of the elongate guides  46 . 
     The elongate rake member  14  is then moved up the inclined surface  12  by actuation of the first hydraulic cylinder  36  to the position shown in  FIG. 3  where the wheels  50  are at the uppermost (right hand) ends of the elongate guides  46 . In operation the assembly  10  may be paused at this position to enable any liquid pushed up with solids urged up by the scraper members  24 , to drain back down the inclined surface  12 . 
     The second hydraulic cylinders  56  are now operated to bring the elongate guides  46  to a horizontal alignment as shown in  FIG. 4 . The elongate rake member  14  is now moved downwardly and to the left as shown in the drawings by operation of the first hydraulic cylinder  36 . As the elongate guides  46  now extend horizontally, as the elongate rake member  14  moves to the left it actually moves horizontally such that it moves clear of the inclined surface  12  and therefore clear of solid material on the inclined surface  12  so as not to push such material back down. 
     When the elongate rake member  14  has reached the fully downwards, i.e. leftward extent, it will occupy the position as shown in  FIG. 5  and also  FIG. 1 . The elongate rake member  14  can now be lowered onto the inclined surface  12  by actuation of the second hydraulic cylinders  56  such that the elongate guides  46  return to an alignment parallel to the inclined surface  12  to the position shown in  FIG. 2 . The process can now be repeated with solid material being moved further up the inclined surface  12 . 
       FIGS. 6 to 8  show a typical water treatment installation  60  incorporating the rake classifier assembly  10 . The installation  60  includes a main tank  62  with an inlet  64  controlled by adjustable vanes  66  to maintain a required level in the main tank  62 . A bridge  68  with a three arm rotating scraper  70  is provided in the main tank  62 , and will rotate slowly in use. An outlet  72  to the main tank  62  is provided diametrically opposite the inlet  64 . 
     Solids will drop out of the liquid in the main tank  62  and be moved by the scraper  70 . A grit collection trap  74  is provided which leads to the inclined surface  12  in the form of an inclined channel  76 . The grit rake assembly  10  will move the solids up the inclined channel  76  clear of the liquid therein, for further processing. 
     The rake classifier assembly  10  will be computer controlled, and a control unit  78  is provided including control for the assembly and also a hydraulic power unit for the first and second hydraulic rams  36 ,  56 . The control unit  78  can be programmed as required and could for instance provide a relatively slow upward movement of the elongate rake member  14  to ensure that liquid does not wash solids back down the inclined surface  12 . As indicated a pause may be provided with the elongate rake member  14  at the upper position. The return of the elongate rake member downwardly could however be carried out more quickly to enable a further lifting sequence to rapidly commence. 
     Proximity sensors may be provided to detect the location of the various movable components of the assembly, and the assembly could be controlled in the light of the detected locations. 
       FIG. 9  shows a second rake classifier assembly  110  which is similar in most respects to the first assembly  10 , and the same reference numerals has been used or equivalent features. In the assembly  110  only the upper second guide arrangement  42  has a second hydraulic cylinder  56 , and the first guide arrangement  40  has no hydraulic cylinder. 
     Crank members  114  are provided on the outside of each of the guide arrangements  40 ,  42  mounted at one end coaxially with the cross members  48 , with the other ends of the crank members  114  pivotally mounting connecting rods  112  which extend between the respective crank members  114  on the first and second guide arrangements  40 ,  42 . This means that as the second hydraulic cylinder  56  on the second guide arrangement  42  is actuated to pivotally move the elongate guides  46 , this causes equivalent pivotal movement of the elongate guides  46  on the first guide arrangement  40 . 
     There are thus described a rake classifier assemblies and also a water treatment installation incorporating such an assembly which has been found to have a number of advantageous features. The operation of the assemblies is relatively simple and can thus provide long term low maintenance operation. These assemblies can also be robustly and inexpensively manufactured. 
     The rake classifier assemblies can be controlled as required, and as indicated could move in different directions at different speeds, and could be paused in position as required. With such controllable arrangements it has been found for instance that the assembly could operate on a steeper inclined surface than would otherwise be the case, as the assemblies can be controlled to prevent solids being washed back down the slope. Accordingly the assembly could be provided in a smaller space than would otherwise be possible. 
     It is to be realized that a wide range of other modifications may be made without departing from the scope of the invention. For instance the cylinders could be pneumatically rather than hydraulically controlled, or other control means could be used, such as linear motors. It may be that a different number of guide arrangements would be used. The elongate rake member may take a different form. 
     Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.