Patent Publication Number: US-7591375-B2

Title: Layered vibratory material conditioning apparatus

Description:
This application claims priority to Provisional Patent Application Ser. No. 60/694,536 filed on Jun. 28, 2005 and entitled, “Layered Vibratory Material Conditioning Apparatus” incorporated herein by reference for all purposes. 

   BACKGROUND OF THE INVENTION 
   Many industries, such as pharmaceutical, food, plastic, and waste, require material particles to be exposed to predetermined conditions, such as heat or cold, as a part of an overall process. Various types of equipment have been developed to integrate the conditioning of particles with other production processes. 
   One such apparatus dries product as the product is gradually moved across conveying surfaces towards the apparatus discharge. The conveying surfaces are porous and enclosed within a vibrating vessel. The vibrations fluidize the particles and cause them to move forward through the apparatus. Air flow normal to the direction of particle flow provides heated or cooled air through the porous surface and the product. Such a single deck, rectangular design requires many square feet of valuable production space. 
   Alternative designs have attempted to reduce the square footage of production space required to condition material. One such design uses a stack of non-vibrating, slowly rotating trays. Material to be conditioned is dropped onto a top tray having several slots providing fluid communication to a lower tray. As the tray of material rotates within a conditioned chamber, a wiper pushes material through one of the slots in the tray. The material from the top tray then drops onto a second tray where the same action is repeated. The material continues to be wiped into slots on successive trays until it is released through a discharge spout at the bottom of the apparatus. While this utilizes less square footage than the first apparatus and provides longer exposure of the material to the predetermined conditions, the trays do not allow vertical air flow through the particles. Further, the trays do not integrate material separation with conditioning. 
   It would be an improvement in the art to have a material conditioner that uses minimal floor space. It would be a further improvement in the art to have a material separator that could be adapted to segregate oversized and/or undersized particles of material as the material is being conditioned. 
   SUMMARY 
   In a first aspect of the invention, a vibratory conditioner includes a plurality of screens having a planar surface through which there is a material feed opening, wherein each screen is retained in vertical alignment such that all planar surfaces are parallel, a chamber within which the parallel screens are retained, means for conditioning air within the chamber to a predetermined temperature and a predetermined humidity level, and a vibratory generator operable to vibrate the chamber and fluidize particles of material retained on a top surface of each screen and to move the fluidized particles in a first direction. 
   In another aspect of the invention, an apparatus for conditioning and classifying material includes a plurality of screens retained within the chamber, wherein each screen has a center orifice and an outer edge, with a material feed opening radially extending through the screen, wherein each porous element has a plurality of pores of a unique predetermined pore size, a cylindrical connector affixed within the center orifice of each of the plurality of screens, wherein each connector interconnects with adjacent cylindrical connectors to retain each screen in a fixed rotational alignment such that the material feed opening through adjacent screens are offset by a fixed offset angle, a vibratory generator operable to vibrate the chamber and fluidize the material on each screen, thereby causing it to move in a first direction, and means for conditioning air within the chamber. 
   In another aspect of the invention, a method for conditioning and classifying particles includes conditioning air in a chamber to a predetermined temperature and a predetermined humidity level, circulating the conditioned air within the chamber, dispensing a plurality of particles into the chamber and onto a first of a plurality of vertically adjacent screens, wherein each porous element has a plurality of pores of a unique predetermined size and a radially extending material feed opening, and wherein the material feed opening of adjacent screens are offset from each other, vibrating the screens to separate particles having a particle size greater than a desired minimum particle size from particles having a particle size less than the desired minimum particle size, directing the particles having a particle size greater than the desired minimum particle size to subsequent screens through the material feed opening in each porous element, collecting the particles having a particle size less than the desired minimum particle size at a bottom portion of the chamber. 
   Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cutaway side view of a vibratory conditioning apparatus. 
       FIG. 2  is a side view of the housing of the vibratory conditioning apparatus. 
       FIG. 3  is a top view of a screen of the vibratory conditioning apparatus. 
       FIG. 4  is a cross sectional view of a screen of the vibratory conditioning apparatus. 
       FIG. 5  is a cross sectional detail of a screen frame retained by the housing. 
       FIG. 6  is a perspective view of the screen stack. 
       FIGS. 7A and 7B  depict flow paths in opposite directions. 
       FIG. 8  is a cutaway side view of a vibratory conditioning apparatus with overs removal. 
       FIG. 9  is cutaway side view of a vibratory conditioning apparatus with low profile vibratory drives. 
       FIG. 10  is an embodiment of the vibratory conditioning apparatus. 
   

   DETAILED DESCRIPTION 
   The claimed subject matter relates to an apparatus for conditioning material. Referring to  FIG. 1 , the inventive vibratory conditioner  100  includes a plurality of screens  110 , a chamber  140 , a means for conditioning the air  160  within the chamber  140  to predetermined parameters, and a vibratory generator  176 . The plurality of screens  110  are retained within the chamber  140 . The means for conditioning air  160  is operative to bring the temperature and humidity levels within the chamber  140  to predetermined levels. The chamber  140  is mounted to a base  154  in a conventional manner by means of resilient members (not shown). The vibratory generator  176 , of conventional design, is securely mounted within the housing floor  152  of the chamber  140  and is operative to fluidize material on screens  110  within the chamber  140 . 
   The chamber  140  is depicted in  FIG. 2  and includes a plurality of housing components  142 , a cover  150 , and a housing floor  152 . Referring to  FIGS. 2 and 5 , housing components  142  preferably are cylindrical defined by a housing wall  144  with an outwardly protruding flange  146  around each of the upper edge  148  and the lower edge  149 . As will be described, a screen  110  may be retained between flanges  146  of two adjacent housing components  142 . A clamp band  156  may be used around the outer periphery of the adjacent flanges  146  to secure one housing component  142  to the next with a screen  110  retained between them. By affixing several housing components  142  together with a screen  110  retained between housing components  142 , a screen stack  102  is created (see  FIG. 1 ). 
   The screen stack  102  may be formed from any number of screens  110 . In discussing the relationship of screens  110  within the screen stack  102 , it is understood that there is a top screen  104  and a bottom screen  106 . It is further understood that in discussing the relation of two screens  110  within the screen stack  102 , there is an upper screen and a lower screen. For screens  110  located between the top screen  104  and the bottom screen  106 , each screen can be an upper screen and a lower screen, relative to the next adjacent screen above or below, respectively. 
   Referring to  FIGS. 1 ,  3  and  4 , each screen  110  is planar and has a plurality of pores  112  of a predetermined size. Material is retained on a screen top surface  108 . The pores  112  increase the exposure of the material to the environmental conditions within the chamber  140 . The screens  110  are preferably round, but may be square or rectangular to match the interior shape of chamber  140 . 
   Referring to  FIGS. 3 ,  4 , and  5 , screens  110  have an screen periphery  114 , at which there is a screen frame  116 . As shown in  FIG. 5 , screen frame  116  is retained between adjacent housing components  142 . Preferably, a gasket  158  is located between the screen frame  116  and the housing component flanges  146  to seal the interface. 
   A material feed opening  120  is present through each screen  110  and radially extends along a portion of the screen  110  for an opening length  122 . The material feed opening  120  has an opening width  124  sufficient to allow material retained on screen top surface  108  to pass through the upper screen  110  onto the lower adjacent screen  110  or to a collection area  190  (shown in  FIG. 1 ). 
   Referring to  FIG. 6 , the material feed opening  120  of each screen  110  is offset from the material feed opening  120  of adjacent screens  110 . That is, the material feed opening  120  of each lower screen  110  is positioned behind the material feed opening  120  of the adjacent upper screen  110  relative to the flow direction  126  of material around the screen  110 . Thus, material dropping onto a lower screen  110  from above must travel along the screen top surface  108 , around screen center  118 , for a predetermined distance. The offset angle  128  between material feed openings  120  of adjacent screens  110 , as measured in the flow direction  126 , will be less than 360 degrees and should be more than 270 degrees to ensure that the material has had adequate exposure to the environmental conditions introduced into the chamber  140 . 
   As shown in  FIGS. 1 ,  3 , and  4 , each screen  110  has a center orifice  130  through which a cylindrical retainer  132  is affixed. The cylindrical retainers  132  provide a circular path for the material to follow by blocking a path to the material feed opening  120  across the center of the screen  110 . Also, stability to the screen  110  is added by the cylindrical retainer  132  as a lower retainer edge  134  of each cylindrical retainer  110  rests on an upper retainer edge  136  of a lower adjacent cylindrical retainer  110 . Further, the cylindrical retainers  132  hold each screen  110  in a fixed rotational alignment, thereby preserving the offset angle  128  of each adjacent material feed opening  120 . To maintain the offset angle  128  of the material feed openings  120  of adjacent screens  110 , the cylindrical retainers  132  may include castellations  138  positioned around the retainer upper edges  136  and retainer lower edges  134 . The castellations  138  along the lower retainer edge  134  of the cylindrical retainer  132  on an upper screen  110  are held between the castellations  138  along the upper retainer edge  136  of the cylindrical retainer  132  of the adjacent lower screen  110 . The castellations  138  ensure that no screen  110  rotates about a center axis  101  relative to the remaining screens  110  in the screen stack  102 . 
   As shown in  FIGS. 7   a  and  7   b , a spiral baffle  184  may be included on the one or more of the screens  110 . The spiral baffle  184  creates a spiral path  186  extending from the screen center  118  to the screen periphery  114  (as shown in  FIG. 7   b ) or from the screen periphery  114  toward the screen center  118  (as shown in  FIG. 7   a ). The fluidized material is directed by the spiral baffle  184  around the screen top surface  108  of the top screen  104 , thereby providing additional exposure to the conditioning provided by the means for conditioning air  160 . The material feed opening  120  may extend across a portion of the spiral path  186  that is adjacent to the screen periphery  114 , as in  FIG. 7   b , or that is adjacent to the screen center  118 , as shown in  FIG. 7   a . Adjacent screens  110  may include reversed paths  184  to maximize the exposure of the material to the conditioning. For example, the screen  110  shown in  FIG. 7   b  may be the top screen  104 , while the screen  110  shown in  FIG. 7   a  is below the top screen  104 . Thus, material directed to the top screen  104  may be conveyed along path  186  to the material feed opening  120  adjacent to the screen periphery  114 . The material dropped through material feed opening  120  on the top screen  104  is then directed along the path  186  of the second screen  110  from the screen periphery  114  to the material feed opening  120  near the screen center  118 . 
   Referring to  FIGS. 1 ,  2 , and  8 , the means for conditioning air  160  within chamber  140  brings the air to a predetermined temperature and humidity level. The predetermined temperature and/or humidity level may be programmed by an operator. The means for conditioning air  160  may include heating and/or cooling units, humidifiers, and/or dehumidifiers. The means for conditioning air  160  may be retained at a location external to chamber  140  with ducts  172  providing conditioned air to the chamber  140  via vents  164  through housing wall  144  or housing floor  152 . An alternative arrangement is shown in  FIG. 9 , in which a set of low profile dual motors  176 ′ are used to vibrate the chamber  140  rather than the more typical vibratory drive associated with round separators as shown in  FIG. 1  as  176 . By including a set of low profile dual motors  176 , a central air pipe  192  may be utilized to introduce conditioned air to the chamber  140 . This has the advantage of providing a more uniform air flow within the chamber  140 . 
   The means for conditioning air  160  within chamber  140  may also include one or more sensors  166  and a controller  168 . The sensors  166  measure the air temperature and/or humidity level within chamber  140 . The controller  168  receives data from the sensor  166  and operates components of the means for conditioning air  160 , such as a heater, cooling unit, humidifier, and/or dehumidifier in response to collected measurements to maintain the predetermined temperature and humidity level within the chamber  140  as measured by the sensor  166 . 
   A means for circulating air  170  within chamber  140  may be included to move conditioned air between and among screens  110 , subjecting material on each screen  110  to the desired air temperature and humidity. The means for circulating air  170  may include a fan or blower to force air from the means for conditioning air  160  through one or more air ducts  162  and vents  164  through housing wall  144  and/or housing floor  152 . Alternatively, a vacuum may be used to pull conditioned air through the chamber  140 , thereby exposing particles to the conditioned air. 
   The vibratory conditioner  100  may also include a means for dedusting particles  174 , wherein dust from the particles retained on the top screen surfaces  108  is periodically removed. Means for dedusting particles  174  may include a blower and vacuum system that provides an air current through the chamber of sufficient strength to separate fine particles that are adhered to more coarse particles and evacuated the fine particles from the chamber  140 . Preferably, a vertical airflow is provided through the chamber  140  to dedust the particles therein. The same blower may be used to dedust particles and to circulate air during processing of the material. The airflow for dedusting particles may have a faster velocity than the airflow for circulating conditioned air when the same blower is used for both functions. 
   As previously stated, the vibratory generator  176  is operable to fluidize material on the screens  110 . The housing floor  152  of the chamber  140  securely mounts to the vibratory generator  176 . The vibratory generator  140  imparts motion to the material on each screen top surface  108  such that the individual particles of material are fluidized and conveyed around the screen  110 . The fluidized material is led by the vibratory generator  176  such that it spirals outward from the center axis  101  in a first direction. As the particles reach the material feed opening  120 , they are gravity fed onto the lower sequential screen  110 . 
   Referring to  FIG. 10 , the chamber  140  may be configured such that a dedusting deck  194  is provided at the top of the chamber  140 . After material is transferred onto the dedusting deck  194 , the dedusting process takes place and dust may be removed through a dust removal spout  196 . A cooling deck  198  may be provided beneath the dedusting deck  194 . The cooling deck  198  may include a spiral baffle  200  to cool the product as it is transferred around the screen of the cooling deck  198  to a center hole  202 . An air inlet  206  directs conditioned air into the chamber  140  beneath the cooling deck  198 . A directing baffle  208  guides the conditioned air from the air inlet  206  upward to flow through the cooling deck screen  198 . The conditioned material may then drop to a perforated plate or screen  204  having a predetermined mesh size to separate oversized material from the product being transferred through the screen. The oversized material remains on the top surface of the screen  204  until the vibratory motion imparted to the chamber  140  eventually causes the oversized material to be removed from the chamber  140  through an overs spout  182 ′. The product, which has been dedusted, conditioned and separated from oversized material falls through the plate or screen  204  and may be removed through a product outlet spout  210 . A chamber floor  212  may be formed to have an arced profile, such as that shown, to facilitate removal of the product through the product outlet spout  210 . 
   Returning to  FIGS. 1 ,  2 , and  8 , the vibratory generator  176  may include a reversible drive system. The reversible drive system provides a reverse flow direction to the particles on the screen top surface  108 . When the flow is reversed, particles still spiral outward from the center axis  101 , however the path is in a second direction, opposite the first direction. 
   By varying the size of the pores  112  in subsequent screen layers, sorting by particle size may also be accomplished as material is conditioned. If classification of particles is incorporated into the vibratory conditioner  100 , through appropriately sized pores  112 , particles having a particle size less than the pore size of the screen fall through the pores  112  to the adjacent lower screen  110  or to the housing floor  152 . Likewise, particles having a particle size greater than the pore size of the screen  110  are moved along the screen top surface  108  as the screen  110  is vibrated. The pore size of each screen  110  in the screen stack  102  may be unique, wherein the pores  112  of each screen  110  are of a different size than the pores  112  of other screens  110  within the chamber  140 . 
   In a first example, all screens  110  have a common pore size, wherein each pore  112  is of a size sufficient to retain a particle having a particle size equal to or greater than the smallest acceptable particle size on the screen top surface  108  of the screen  110 . Particles having a particle size greater than the pore size are retained on the screen top surface  108  of the top screen  104  until reaching the material feed opening  120 . Material deposited onto the second screen  110  is, likewise, retained on the screen top surface  108  until reaching the material feed opening  120  of the second screen  110 . In this manner, particles having a particle size greater than the pore size of the screens  110  continue to be conditioned as they are transferred along the screen top surface  108 . Particles having a particle size less than the smallest allowable particle size fall through successive screens  110  until reaching a collection area  190  on or near housing floor  152 . The undersized particles are then segregated from the particles having the desired particle size. 
   A modification of the first example would be to remove the undersized material before beginning the conditioning process. This may be accomplished by vibrating the chamber to remove the undersized particles, that is, to dedust the acceptable particles. After removing the undersized particles, conditioned air may be introduced to the chamber and the vibratory direction modified to convey acceptable material over the screen top surface  108  to the material feed opening  120 . 
   In a second example of simultaneous sorting and conditioning of material, a top screen  104  has pores  112  of a size through which particles having the maximum acceptable particle size may pass. Thus, oversized particles are retained on the top screen  104  and may be removed by a spout  182  or other removal system. Particles having a particle size less than the maximum acceptable size pass through the top screen  104  to the second screen  110 . The second screen  110  is sized to retain particles having an acceptable particle size on the screen top surface  108  until the particles have reached the material feed opening  120 . Subsequent screens  110  in the screen stack  102  also maintain the particles having an acceptable particle size on the screen top surface  108 , thereby providing additional exposure of the environmental conditions to the acceptable particles. 
   The third example is a combination of the first two examples. The top screen  104  may have pores  112  of a size sufficient to retain oversized particles on the screen top surface  108 . The oversized particles on the top screen  104  are removed. Undersized particles and particles having a size within an acceptable range pass through the pores  112  of the top screen  104  onto the second screen  110 . All of the subsequent screens  110  may have pores  112  of a size sufficient to permit the passage of undersized particles. The undersized particles are collected in an undersized particle collection area  190  on or near the housing floor  152 . Particles having a particle size within the acceptable range are transferred along the screen top surface  08  of each successive screen  110  until passing through the respective material feed opening  120  to the next screen  110  or the finished product collection area  190 . 
   In a fourth example, wet material may be retained on a top screen  104  and subjected to a drying environment in the chamber. As the material dries, it may separate or shrink, depending upon the material involved. After the material has separated into particles of less than a predetermined size or after the material has reduced in size to less than a predetermined size, the material can pass through the top screen. Sequential screens may have decreasingly smaller pore sizes, requiring additional drying time for material to pass therethrough. In this manner, the level of dryness of a particular material may be determined based upon the screen on which the material is present at any time. The level of dryness desired for a material and the particle size variation during the drying process can be used to determine the number of sequential screens required to sufficiently dry the material. 
   While the claimed subject matter has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the claimed subject matter as disclosed herein. Accordingly, the scope of the claimed subject matter should be limited only by the attached claims.