Patent Publication Number: US-9849486-B2

Title: Vibratory apparatus with multiple screening decks

Description:
BACKGROUND 
     This patent is directed to a vibratory apparatus with multiple decks and a method for operating such a vibratory apparatus, and, in particular, to a vibratory screening apparatus with multiple screening decks and a method for use of the same. 
     It is common to have a multi-deck screening apparatus, with each successive screening deck described as being above the preceding deck, and the surface of each lower deck being completely covered by the deck immediately above that lower deck, from inlet to outlet of the apparatus. The largest material flows over the uppermost deck from the inlet to the outlet, while smaller material flows through the uppermost deck to the next lowest deck. This process repeats until the smallest material passes through the lowestmost deck out of the apparatus, or to a floor and then along the floor and out of the apparatus. The material that does not pass through a particular screening deck may be collected at the outlet end of that screening deck. 
     One disadvantage of such a screening apparatus is that to clean, repair or replace the lowermost deck, or any of the intermediate decks, one must first remove the upper decks. Moreover, it is not possible to visualize from above the motion of the material across the lowermost deck, for example, because of the intermediate decks. Of course, while a screening apparatus having a single deck would avoid these disadvantages, such a solution avoids disadvantages of a multi-deck screening apparatus while also losing the advantages of a multi-deck screening apparatus. 
     SUMMARY 
     According to one aspect of the present disclosure, a vibratory apparatus includes a deck assembly and an exciter coupled to the deck assembly. The deck assembly has a longitudinal axis, an inlet end, and an outlet end spaced from the inlet end along the longitudinal axis. The deck assembly includes a plurality of deck sections each having a plurality of openings therethrough. Each deck section has an upstream edge and a downstream edge disposed transversely relative to the longitudinal axis, the upstream edge disposed closer longitudinally to the inlet end and the downstream edge disposed closer longitudinally to the outlet end. The downstream edge of each successive deck section is disposed closer longitudinally to the outlet end than the downstream edge of each preceding deck section. The upstream edge of each successive deck section is disposed closer longitudinally to the upstream edge of each preceding deck section than the downstream edge of the preceding deck section is disposed to the upstream edge of the preceding deck section, thereby defining an overlapping portion of the preceding deck section and a non-overlapping portion of the preceding deck section. The overlapping portion has larger openings than the non-overlapping portion for each preceding deck section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It is believed that the disclosure will be more fully understood from the following description taken in conjunction with the accompanying drawings. Some of the figures may have been simplified by the omission of selected elements for the purpose of more clearly showing other elements. Such omissions of elements in some figures are not necessarily indicative of the presence or absence of particular elements in any of the exemplary embodiments, except as may be explicitly delineated in the corresponding written description. None of the drawings are necessarily to scale. 
         FIG. 1  is a perspective view of a vibratory apparatus, and in particular a vibratory screening apparatus, as viewed from an outlet end and having multiple decks or deck sections; 
         FIG. 2  is a side view of the vibratory apparatus of  FIG. 1 ; and 
         FIG. 3  is an enlarged, perspective view of a portion of the exciter of the apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS 
       FIGS. 1-3  illustrate a vibratory apparatus  100 , in the form of a vibratory screening apparatus, screener, or screen. The screen  100  includes a deck assembly  102  and an exciter  104  coupled to the deck assembly  102 . 
     As illustrated, the vibratory screen  100  is a two-mass, sub-resonant frequency design. That is, the exciter  104 , or first mass, is used to drive the deck assembly  102 , or second mass, and thus the screen  100  may be referred to as a two-mass unit. One advantage of using a two-mass configuration is that the two-mass configuration responds positively to loading. That is, as the loading increases, the screen  100  will actually provide an increase in stroke, rather than a reduction in stroke (or dampening). As such, a two-mass screen of lower power requirements may be used in place of a direct-drive or brute force unit to process a similar loading, or a two-mass screen of similar power requirements may be used to process a much larger load. However, according to other embodiments of the present disclosure, a direct-drive or brute force unit may be used instead. The details of one embodiment of the exciter  104  will be discussed below. 
     In general, the deck assembly  102  has a longitudinal axis  110  (see  FIG. 1 ). The assembly  102  also has an inlet end  112  and an outlet end  114 . The outlet end  114  is spaced from the inlet end  112  along the longitudinal axis  110  of the deck assembly  102 , with the inlet and outlet ends  112 ,  114  being opposite ends of the assembly  102 . While the end  112  is referred to as the inlet, and the end  114  is referred to as outlet, it will be recognized that because the deck assembly  102  may have openings throughout, material will be exiting the deck assembly  102  between the inlet end  112  and the outlet end  114 . However, the general motion of material across the deck assembly  102  is from inlet end  112  to outlet end  114  according to the operation of the exciter  104 . 
     The deck assembly  102  includes a plurality of deck sections. As best seen in  FIG. 2 , the illustrated embodiment has a deck assembly  102  with three deck sections  116 ,  118 ,  120 . The deck sections  116 ,  118 ,  120  each have a plurality of openings therethrough, although the openings may not be of the same size for all portions of the deck sections  116 ,  118 . It will be recognized that a greater number of deck sections may be included, or two deck sections may define the deck assembly  102 . 
     Furthermore, it will be recognized that the screen  100  may include additional deck sections or portions of deck sections that do not define part of the deck assembly  102 . For example, there may be deck sections that precede (i.e., before section  116 ) or succeed (i.e., after section  120 ) the deck assembly  102  that do not include the features of the deck sections  116 ,  118 ,  120  that cause the deck sections  116 ,  118 ,  120  to be considered to be part of the deck assembly  102 . 
     Each deck section  6 ,  118 ,  120  has an upstream edge  122 ,  124 ,  126  and a downstream edge  128 ,  130 ,  132  disposed transversely relative to the longitudinal axis  110 . In so describing the edges  122 ,  124 ,  126  and  128 ,  130 ,  132 , it is not intended that the transverse nature of the edges relative to the longitudinal axis  110  limit the edges to a perpendicular orientation relative to the longitudinal axis  110 , although that is the orientation as illustrated. Instead, it is intended that “transverse” include edges that are at an angle to the longitudinal axis  110 , and as such may be orthogonal to the longitudinal axis  110  according to particular embodiments (such as the embodiment illustrated). 
     The upstream edge  122 ,  124 ,  126  of each deck section  116 ,  118 ,  120  is disposed closer longitudinally to the inlet end  112 , and the downstream edge  128 ,  130 ,  132  is disposed closer longitudinally to the outlet end  114 . That is, the upstream edge  122 ,  124 ,  126  is in the direction of the inlet end  112 , and the downstream edge  128 ,  130 ,  132  is in the direction of the outlet end  114 . 
     The downstream edge  130 ,  132  of each successive deck section  118 ,  120  is disposed closer longitudinally to the outlet end  114  than the downstream edge  128 ,  130  of each preceding deck section  116 ,  118 . It will be recognized that how much closer the edge  130 , for example, is to the outlet end  114  than the edge  128  will depend on the length of the sections  116 ,  118 , as well as the relative position of the upstream edges  122 ,  124  of the sections  116 ,  118 . 
     In that regard, the upstream edge  124 ,  126  of each successive deck section  118 ,  120  is disposed closer longitudinally to the upstream edge  122 ,  124  of the preceding deck section  116 ,  118  than the downstream edge  128 ,  130  of the preceding deck section  116 ,  118  is disposed to the upstream edge  122 ,  124  of the preceding deck section  116 ,  118 . In other words, the upstream edge  124 ,  126  of each successive deck section  118 ,  120  is disposed between the upstream edge  122 ,  124  and the downstream edge  128 ,  130  of the preceding deck section  116 ,  118  when viewed from above, although the deck sections  116 ,  118 ,  120  themselves are spaced apart in an axis that lies in the plane of the drawing page, and which will be referred to herein as the elevation axis, or elevation for short. 
     The relative position of the upstream and downstream edges described in the preceding paragraph defines an overlapping portion  140 ,  142  for each preceding deck  116 ,  118  and a non-overlapping portion  144 ,  146 . As illustrated, the overlapping portions  140 ,  142  have larger openings than the non-overlapping portions  144 ,  146  for each preceding deck section  116 ,  118  (in the case of non-overlapping portion  144 , there may be no openings at all, such that the openings of overlapping portion  140  may still be referred to as larger in size). In fact, the overlapping portions  140 ,  142  may also have larger openings than at least a region of the successive decks  118 ,  120  immediately below the overlapping portions  140 ,  142 . As will be explained below, the relative size of the openings may be discussed in terms of a minor dimension, although in other cases it may be more convenient to discuss the relative size of the openings in terms of area encompassed by the edge of the opening, for example. 
     The screen  100  as previously described has a number of advantages over conventional screens, which have a first deck that extends from the inlet end to the outlet end disposed at a higher elevation relative to a second deck that also extends from the inlet end to the outlet end. By arranging the deck sections  116 ,  118 ,  120  as described above, a significant portion of an upper surface  150 ,  152 ,  154  of each deck section  116 ,  118 ,  120  is accessible and visible without having to access or move other deck sections  116 ,  118 ,  120 . This arrangement provides for ease of viewing, ease of cleaning, and ease of replacement. Furthermore, if other materials are to be added to the material traveling over the surfaces  150 ,  152 ,  154 , such as water for example, then the access provided by this arrangement also facilitates that activity as well. 
     Furthermore, the screen  100  as described above has a number of advantages over a single deck. To begin, the deck assembly  102  may provide more deck area and improved efficiency relative to a single deck. Furthermore, the changes in elevation between the deck sections  116 ,  118 ,  120  may create a cascading, tumbling effect in the material passing over the deck assembly  10  between the inlet end  112  and the outlet end  114 . This cascading effect may also increase screening efficiency relative to a single deck, for example by permitting the material to remix at each transition of the deck assembly  102  to allow the material to remove itself from suspension within the material bed and flow through the deck openings or present itself repeatedly to the deck openings. This may also provide a scrubbing effect that limits or prevents binding within the material on the surfaces  150 ,  152 ,  154 . Of course, the cascading motion of the material between deck sections  116 ,  118 ,  120  may require reinforcement of the deck sections  116 ,  118 ,  120  in those regions of the deck sections  118 ,  120  that receive the material from preceding sections  116 ,  118 . 
     Having thus described the screen  100  in general terms, the details of the screen  100  are provided below. 
     The screen  100 , as illustrated, is symmetrical about the longitudinal axis  110  that extends from the inlet end  112  to an outlet end  114 . Consequently, each side is a mirror image of the other side view. For purposes of convenience only, only one side view is provided, viewed from the right hand side of the screen  100  as defined from the inlet end  112  in the direction of the outlet end  114 . 
     The screen  100  includes a trough  160  in which the deck assembly  102  may be disposed. The trough  160  may include side walls  162 ,  164  (see  FIG. 1 ), the side walls  162 ,  164  being parallel to the longitudinal axis  110 . Each of the deck sections  116 ,  118 ,  120  has first side edges  170 ,  174 ,  178 , and second side edges  172 ,  176 ,  180 , each of which may be parallel to the longitudinal axis  110 . As illustrated, the first side edges  170 ,  174 ,  178  may be attached to the side wall  162 , and the second side edges  172 ,  176   180  may be attached to the side wall  164 . In particular, the edges  170 ,  174 ,  178  may be attached to an inner surface of the side wall  162 , while the edges  172 ,  176 ,  180  may be attached to an inner surface of the side wall  164 . 
     According to certain embodiments, there may be an intermediate wall that divides the decks  116 ,  118 ,  120  into first and second regions that extend between the inlet and outlet ends  112 ,  114 , In fact, the decks  116 ,  118 ,  120  may be divided into first and second subdecks, the first subdeck defining the first region and the second subdeck defining the second region, and the first and second subdecks being attached at first edge to either the side wall  162  or the side wall  164  and at a second edge to the intermediate wall. The first and second regions may be referred to as the right and left regions, as observed from the inlet end  112  in the direction of the outlet end  114 . 
     As noted above, each of the deck sections  116 ,  118 ,  120  has at least a first portion that has a plurality of apertures or openings formed therethrough. This region of the deck sections  116 ,  118 ,  120  may also be referred to as foraminous, and the deck sections  118 ,  120  may be referred to as a foraminous deck sections, while deck section  116  may be referred to as a partially foraminous deck section. The apertures or openings may have a circular shape, but the shape of the aperture is not limited to such a shape. For example, the apertures may be in the form of an elongated slot, having a major axis and a minor axis with rounded ends at either end of the major axis. Such elongated apertures may be aligned with the longitudinal axis  110 , or may be transverse to the longitudinal axis  110 ; in fact, the apertures may alternate their angle relative to the longitudinal axis along different rows of apertures that are generally aligned with the longitudinal axis  110 , similar to a herringbone pattern. 
     Whether the shape of the aperture is circular or non-circular (such as the slot described above), the aperture may be described as having a minor dimension. The minor dimension may be the diameter of a circular aperture (where there is only a single dimension), or the minor axis of an elongated slot-like aperture. Either event, according to certain embodiments, the minor dimension of the apertures or openings of the overlapping sections  140 ,  142  may be 18 mm, while the minor dimension of the openings of the non-overlapping section  146  and of the openings in the deck section  120  may be 2.2 mm. As such, the openings of the overlapping portions  142  of the deck section  118  may have a minor dimension that is at least five, six, seven, or eight times greater than a minor dimension of the openings of the non-overlapping portion  146  of the deck section  118 . 
     According to the illustrated embodiment, the non-overlapping portions  144 ,  146  are planar and at least a region of the overlapping portions  140 ,  142  are also planar. That is, the plate or other structure that defines each of the portions  140 ,  142 ,  144 ,  146  of deck sections  116 ,  118  lies within a given plane. This is not to suggest that the portions  140 ,  142 ,  144 ,  146  may not have localized regions that do not lie within the plane, but that the majority of the region described lies within a given plane. This description also does not exclude the possibility of structures being attached to the surfaces  150 ,  152 ,  154 , such that the structures project or extend from the surfaces  150 ,  152 ,  154 . 
     The overlapping portions  140 ,  142  or regions thereof just described may extend at an angle to a plane in which the non-overlapping portion  144 ,  146  is disposed. For example, the overlapping portion  142  of the deck section  118  may extend at an angle to a plane in which the non-overlapping portion  146  of the deck section  118  is disposed. It may also be described that the downstream edges  120 ,  130  are turned up relative to the upstream edges  122 ,  124 . As illustrated, the angle is an acute angle of less than 10 degrees, and because of the relatively steep angle of the outlet end  114  relative to the inlet end  112 , the downstream edges  128 ,  130  are at a lower elevation relative to the upstream edges  122 ,  124  even though the overlapping and non-overlapping portions are disposed at an angle to each other. Still, it is believed that the angle of the overlapping portions  140 ,  142  relative to the non-overlapping portions  144 ,  146  may retard the movement of the material across the surfaces  150 ,  152 , which delay may increase the depth of the material on those surfaces  150 ,  152  and may increase the dwell time of the material on those surfaces  150 ,  152 . 
     The deck section  116  may have portion that does not have any apertures, holes, etc., such as the non-overlapping region  144 . This initial region may be used to receive the material that will be passed over the deck sections  116 ,  118 ,  120 . The initial region may be inclined relative to the remainder of the deck sections  116 ,  118 ,  120  so as to encourage the material disposed on the initial region to move from the initial region to the remainder of the deck sections  116 ,  118 ,  120 . 
     The deck sections  116 ,  118 ,  120  may have a liner disposed on a transporting surface thereof. The liner may include multiple plates, and may define, at least in part, the openings or apertures that pass through the deck assembly  102 , for example. In one exemplary embodiment, the liner may be used to increase the resistance of the deck sections  116 ,  118 ,  120  to wear. 
     The trough  160  may also include or more crossbeams or pairs of crossbeams that are attached to and depend between the side wall  162 ,  164 . In an embodiment of the apparatus where the trough  160  includes an intermediate wall, the crossbeams may be attached to the intermediate wall well. According to certain embodiments, there are two pairs of crossbeams adjacent the inlet end  112  and a further pair at the outlet end  114 . The crossbeams would be spaced from the surfaces  150 ,  152 ,  154  of the deck sections  116 ,  118 ,  120  so as to permit material to move freely along the surfaces  150 ,  152 ,  154 . 
     The deck assembly  102  is supported by resilient members (e.g., coil springs, also referred to as isolation springs)  190  on a frame  192 . The frame  192  is disposed on a foundation, which may be the ground story of a building or which may be an upper story of such a structure; in fact, vibratory screening units are typically mounted at the uppermost levels of the buildings in a mining processing plant, which elevations can exacerbate issues with the vibrations generated by such screens. The resilient members or isolation springs  190  act to isolate the screen  100  from the foundation. That is, the resilient members  190  act to minimize the transmission of the dynamic forces generated during operation of the screen  100  to the frame  192  and the underlying foundation. 
     More specifically, the isolation springs  190  are attached to the trough  160 , which is in turn attached to the deck assembly  102  as described above. The trough  160  may further include one or more mounting brackets  194 ,  196 ,  198 ,  200 . The mounting brackets  194 ,  198  may be joined or attached to an outer surface of the side wall  162 , while the mounting brackets  196 ,  200  are joined or attached to an outer surface of the side wall  164 . The isolation springs  190  are attached at a first end  202  to one of the mounting brackets  194 ,  196 ,  198 ,  200  and at a second end  204  to the frame  192 . 
     As mentioned above, the apparatus  100  also includes the exciter  104 . The exciter  104  is coupled to the trough  160  (and the deck assembly  102 ) via the links and reactor springs. In particular, the exciter  104  is supported on the first and second side walls or sides  162 ,  164  of the trough  160 . The details of the exciter  104  are now discussed with reference first to  FIG. 1 . 
     The exciter  104  includes a frame with first and second side walls  210 ,  212  parallel to the longitudinal axis  110 . The exciter  104  also includes three crossbeams  214 ,  216 ,  218  that are connected at opposite ends to an inner surface of the side walls  210 ,  212 . The exciter  104  further includes two motor mounts  220 ,  222  that are attached to the crossbeams  214 ,  216 ,  218 . As illustrated, the motor mount  220  is attached to and depends between the crossbeams  214 ,  216 , and the motor mount  222  is attached to and depends between the crossbeams  216 ,  218 . The motor mounts  220 ,  222  are attached to and depend between the crossbeams  214 ,  216 ,  218  at the midpoints of the crossbeams  214 ,  216 ,  218  (i.e., along the longitudinal axis  110  of the apparatus  100 ). 
     The details of the motor mounts  220 ,  222  are now explained with reference to the motor mount  222  and  FIG. 3 , although a similar explanation would be applicable to the motor mount  220 . The motor mount  222  includes first and second mounting plates  230 , each of which includes an opening  234 ,  236  for a motor assembly  238 . The motor assembly  238  includes a motor  240  with a shaft disposed along an axis  242 . The axis  242  of the motor  240  intersects the axis  110  of the apparatus  100  at an angle as viewed from above; as illustrated, the axes  110 ,  242  intersect at a right angle (i.e., the axes are orthogonal). The axis  242  may also be described as transverse to the longitudinal axis  110  according to the definition provided above. A pair of eccentric weights is attached at either end of the motor shaft, and rotates about the axis  242 . 
     As mentioned previously, the exciter  104  (or more particularly, the side walls  210 ,  212  or crossbeams  214 ,  216 ,  218  of the exciter  104 ) are attached to the deck sections  116 ,  118 ,  120  (or more particularly, the side walls  162 ,  164  of the trough  160 ) via the links and reactor springs as illustrated in  FIG. 2 . In particular, the links and springs may be grouped into pairs, with each pair of links and springs inclined at opposing angles to the horizontal (for example, the links may form an obtuse angle with the horizontal, while the paired springs may form an acute angle with the horizontal). The links may be attached at a first end to the exciter  104  and a second end to the trough  160 , while the springs may be attached at a first end to the exciter  104  and a second end to the trough  160 . As such, the first side  162  is coupled to the first side  210  and the second side  164  is coupled to the second side  212  through the links and springs. 
     In operation, material is introduced into the screen  100  at the inlet end  112 . With the exciter  104  activated, the material passes over the surfaces  150 ,  152 ,  154  between the inlet end  112  and the outlet end  114 . Because of the inclination of the screen  100  between the inlet end  112  and the outlet end  114 , gravity may also assist in the motion of the material over the surfaces  150 ,  152 ,  154  and between the deck sections  116 ,  118 ,  120 . 
     Material that is larger than the apertures may pass along the deck section  116  from the inlet end  112  to the downstream edge  128 , while material that is smaller than the apertures may fall through the deck section  116 . In particular, certain material may pass through the overlapping portion  140  of the deck section  116  and onto the deck section  118 , while other larger material may pass over the downstream edge  128  of the deck section  116 . Material that is larger than the apertures of deck section  118  may pass along the deck section  118  from the upstream edge  124  to the downstream edge  130  at least until the overlapping section  142 , while material that is smaller than the apertures may fall through the deck section  118  and out of the screener or onto a floor of the trough  160 . Again, a fraction of the larger material may pass through the overlapping portion  142  of the deck section  118  and onto the deck section  120 , while other larger material may pass over the downstream edge  130  of the deck section  118 . The material passing through or over the overlapping portion  142  may then pass along the deck section  120  and either through the deck section  120  or to the outlet end  114 . 
     Embodiments of the screen  100  may include one or more of the following advantages. As mentioned above that the screen  100  may facilitate viewing of the material passing through the screen  100  between the inlet and outlet ends  112 ,  114 , as well as cleaning and repair/replacement of the deck sections  116 ,  118 ,  120 . The structure of the screen may also facilitate introduction of material to the screen  100 . Moreover, the screen  100  (and more particular the deck assembly  102 ) achieves this while improving the efficiency of the screen through the cascading, tumbling action of the material through the screen  100 . 
     Although the preceding text sets forth a detailed description of different embodiments of the invention, it should be understood that the legal scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment of the invention since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention. 
     It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘ ————— ’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done fir sake of clarity only so as to not confuse the reader, and it is not intended that such claim term be limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112.