Patent Publication Number: US-2023150758-A1

Title: Modular auto-cleaning hopper assembly

Description:
BACKGROUND 
     The present application relates generally to a hopper for feeding raw materials to a manufacturing system, and more particularly to a modular, auto-cleaning hopper that is constructed with interconnected modular units that enable the hopper to transported and assembled easily and efficiently. 
     Conventional hoppers are typically large, pyramidal or cone-shaped containers used in industrial processes to hold particulate matter or a flow-able material such as dust, gravel, nuts, seeds or another raw material. Raw material is loaded into a hopper through an inlet at or near the top portion of the hopper. The raw material fills the hopper and is stored until needed for an industrial process. A hopper usually has angled interior walls to cause the raw material to flow downwardly towards an outlet at a bottom of the hopper. When the raw material is needed in the industrial process, the outlet is opened and the raw material flows out of the hopper through the outlet. Industrial hoppers are commonly made with stainless steel and are very large in size. Therefore, the materials for constructing the hopper are delivered to an industrial site and then the hopper is built at the site. Given the size of most industrial hoppers, the hoppers require significant time and money to transport and construct the hoppers at a site. 
     Furthermore, the interior of most hoppers accumulates dust and raw materials that stick to the inside surfaces of the hoppers. The dust and raw materials must be cleaned off of the inside surfaces when changing the raw material being stored in a hopper or to minimize contamination of new raw materials being loaded into the hoppers. Most hoppers have a door on the housing of the hopper that enables a person to access the interior of the hopper to clean the inside surfaces using a pressure washer, pressurized air or other cleaning methods. Cleaning hoppers in this way requires time and effort and also requires that the industrial process be stopped for a period of time during cleaning. As such, the cleaning process for hoppers increases the operating expense of the industrial process. 
     Therefore, it is desirable to provide a modular hopper that is easily transported and assembled at a desired location and that has an automatic cleaning system that efficiently removes dust and material debris from the interior of the hopper. 
     SUMMARY 
     The present hopper assembly is configured for receiving and storing raw materials and then supplying the raw materials to a manufacturing system, where the modular hopper assembly is constructed with multiple pre-fabricated modular units that enable the hopper assembly to be easily and efficiently transported and constructed at a site. 
     In an embodiment, a modular hopper assembly is provided and includes a plurality of pre-fabricated upper hopper modular units, a plurality of pre-fabricated middle hopper modular units, a plurality of pre-fabricated lower hopper modular units and a plurality of support members configured as a base, where the upper hopper modular units, the middle hopper modular units and the lower hopper modular units are each assembled, and then the assembled upper hopper modular units, the assembled middle hopper modular units and the assembled lower hopper modular units are connected together to form a hopper, where the hopper is mounted on the base. 
     In another embodiment, a method of assembling a modular hopper assembly at a site includes assembling a plurality of pre-fabricated upper hopper modular units as an assembled upper hopper structure, assembling a plurality of pre-fabricated middle hopper modular units as an assembled middle hopper structure, assembling a plurality of pre-fabricated lower hopper modular units as an assembled lower hopper structure and assembling a plurality of support members as a base unit. The method also includes connecting the assembled upper hopper structure, the assembled middle hopper structure and the assembled lower hopper structure to form a hopper, and mounting the hopper on the base unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of the present modular hopper assembly. 
         FIG.  2    is a side view of the modular hopper assembly of  FIG.  1   , where an opposing side view is a mirror image thereof. 
         FIG.  3    is a side view, which is adjacent to the side shown in  FIG.  2   , where an opposing side view is a mirror image thereof. 
         FIG.  4    is a perspective view of a base member of the modular hopper assembly of  FIG.  1   . 
         FIG.  5    is a perspective view of a base plate of the modular hopper assembly of  FIG.  1   . 
         FIG.  6    is a perspective view of a support member of the modular hopper assembly of  FIG.  1   . 
         FIG.  7    is a perspective view of the lower hopper units of the modular hopper assembly of  FIG.  1   . 
         FIG.  8    is a perspective view of the middle hopper units of the modular hopper assembly of  FIG.  1   . 
         FIG.  9    is a perspective view of the upper hopper units of the modular hopper assembly of  FIG.  1   . 
         FIG.  10    is a perspective view of a hopper frame of the middle hopper units of  FIG.  8   . 
         FIG.  11    is a perspective view of the hopper frame of  FIG.  10    and a panel frame attached to the hopper frame. 
         FIG.  12    is a perspective view of panels attached to the panel frame of  FIG.  11   . 
         FIG.  13    is a perspective view of the hopper frame, the panel frame and panels assembled together. 
         FIG.  14    is an enlarged, fragmentary perspective view showing a bracket of the panel frame attached to the hopper frame of  FIG.  13   . 
         FIG.  15    is a side view showing the bracket of the panel frame attached to the hopper frame. 
         FIG.  16    is a fragmentary, side view of a support member of the panel frame and a panel. 
         FIG.  17    is a fragmentary, enlarged cross-section view of a support member connected to a panel. 
         FIG.  18 A  is a top perspective view of a side roof unit of the modular hopper assembly of  FIG.  1   . 
         FIG.  18 B  is a bottom perspective view of the side roof unit of  FIG.  18 A . 
         FIG.  19 A  is a perspective view of a plate assembly of a central roof unit of the modular hopper assembly of  FIG.  1   . 
         FIG.  19 B  is a perspective view of a roof frame of the central roof unit of the modular hopper assembly of  FIG.  1   . 
         FIG.  19 C  is a perspective view of a base plate assembly of the central roof unit of the modular hopper assembly of  FIG.  1   . 
         FIG.  20    is a perspective view of connectors for the support members of the base shown in  FIG.  1   . 
         FIG.  21    is an enlarged, fragmentary perspective view the support members of  FIG.  20   . 
         FIG.  22    is a perspective view of the side and central roof units attached to the upper hopper units where the upper hopper units are separated from each other. 
         FIG.  23    is a perspective view of the upper hopper units with the side and central roof units of  FIG.  22    aligned with the middle hopper units. 
         FIG.  24    is a perspective view of the upper hopper units and the middle hopper units attached to each other and aligned with the lower hopper units and underlying base. 
         FIG.  25    is a perspective view of the upper hopper units, the middle hopper units and the lower hopper units attached to each other and aligned with a base unit of the base. 
         FIG.  26    is a fragmentary, perspective view of the hopper showing the autocleaning system. 
         FIG.  27    is an enlarged, fragmentary perspective view the air supply devices of the hopper. 
     
    
    
     DETAILED DESCRIPTION 
     The present hopper assembly is configured for receiving and storing raw materials and supplying the raw materials to a manufacturing system, and more particularly, to a modular hopper assembly constructed with multiple pre-fabricated modular units that form a hopper mounted on a base, where the pre-fabricated modular units enable the hopper assembly to be easily and efficiently transported and constructed at a site, such as within a commercial or industrial building or factory. 
     Referring now to  FIGS.  1 - 3   , the present modular hopper assembly  40  includes a base  42  that provides stability and supports the weight of the hopper assembly, a hopper  44  that receives, stores and supplies one or more raw materials, such as a granular material or powder or any free flowing dry bulk material, and a roof structure  46  that covers the hopper  44  and supports equipment associated with the hopper. 
     As shown in  FIGS.  1 - 4   , the base  42  includes a plurality of pre-fabricated support members  48  that are attached to each other to form one or more pre-fabricated base units  50  that support the hopper  44  at a designated height above an underlying support surface, such as the floor or ground. As shown in  FIG.  1   , a first base unit  50   a  includes four support members  48  that are spaced from each other at each corner of the hopper assembly  40 . A second base unit  50   b  also includes four support members  48   that are spaced from each other and attached to the support members of the first base unit  50   a  as described below. A third base unit  50   c  includes four support members  48  that are spaced from each other and attached to the support members of the second base unit  50   b . As described above, the base  42  supports the hopper  44  where the height of the hopper, and more specifically, the height of the outlet  52  of the hopper is determined based on the height of a transport vehicle, such as a truck, or a container, a conveyor belt or other piece of equipment associated with a manufacturing process, in which the raw material stored in the hopper  44  is to be supplied. Thus, the support members  48 , i.e., base units  50 , are attached to each other in a vertical direction to form the base  42 , until the hopper is positioned at the desired height. In this regard, the number of support members  48  (base units) needed to construct the base  42  is based on the height of each of the support members, where the height of the support members  48  may be one foot, four feet, ten feet or any suitable height needed for construction of the hopper assembly  40 . 
     In the illustrated embodiment, each support member  48  includes an upper plate  54  and a lower plate  56 , where the upper plate and the lower plate are spaced apart and connected to each other by a support body  58  formed by a plurality of structural members  60  and brace plates  62 . Preferably, the upper plate  54 , the lower plate  56  and the support body  58  (structural members and brace plates) are attached to each other by welding, but may also be attached to each other using one or more connectors, such as rivets, bolts or screws, or any suitable connectors or attachment methods. The upper plate  54  and the lower plate  56  each include a square-shaped, planar base member  64  with a central through-hole  66 . As shown, outer edge  68  of the upper plate  54  and the outer edge  70  of the lower plate  56  extend a distance beyond the outer surface  72  of the support body  58 . In the illustrated embodiment, the bottom surfaces  74  of the support members  48  of the first base unit  50   a  of the base  42 , are each attached to a base plate  76  shown in  FIG.  5   . Each base plate  76  includes a base member  78 , which is planar and has a designated thickness, where the outer edge  80  extends beyond the outer edge  70  of the lower plate  56 . Further, each base plate  78  includes four alignment tabs  82  on the upper surface  84  of the base plate, where the alignment tabs  82  each have indents  86  that correspond to the corners of the lower plate  56 . In this way, the corners of the lower plate  56  are aligned with and placed in the indents  86  to align the support member  48  on the base plate  76 . Each base plate  76  is then attached to the support members  48  by welding or another suitable attachment method. In this embodiment, the upper plate  54 , the lower plate  56 , the structural members  60  and the brace plates  62  of the support member  48  are preferably made of a metal, such as stainless steel, but may be made with a composite material, or any suitable material or combination of materials.. 
     For additional support and stability, the base units that are mounted above the first base unit  50   a , such as the second base unit  50   b  or the third base unit  50   c  shown in  FIG.  1   , each include cross supports  88  ( FIG.  6   ) that are attached to the support members  48  of the base units  50   b  and  50   c . The cross supports  88  each include opposing end plates  90 , and a top member  92  and a bottom member  94  that are spaced from each other, where the top member and the bottom member extend between and are attached to the end plates  90 . As shown, a plurality of intermediate members  96  are spaced from each other and are attached to the top member  92  and the bottom member  94 . It should be appreciated that one cross support or a plurality of the cross supports  88  may be attached to the support members  48  of the base units  50 . In this embodiment, the support members  48 , the base plates  76  and the cross supports  88  are preferably made of a metal, such as stainless steel, but may be made with any suitable material or combination of materials. 
     Referring to  FIGS.  7 - 17   , the hopper  44  of the modular hopper assembly  40  includes pre-fabricated lower hopper units  98  ( FIG.  7   ), pre-fabricated middle hopper units  100  ( FIG.  8   ) and pre-fabricated upper hopper units  102  ( FIG.  9   ), that are assembled together to form the hopper. 
     Referring to  FIGS.  7 ,  16  and  17   , the pre-fabricated lower hopper units  98  each include a frame  104  made of a plurality of support members  106  that are attached together by welding or another suitable attachment method, where the frame is the support structure for each of the lower hopper units. The frame  104  is preferably made of a metal, such as stainless steel, but may be made with a composite material, or any suitable material or combination of materials. In the illustrated embodiment, each of the support members  106  have a plurality of integrally formed tabs  108  that are spaced apart along the length of the support members. The tabs  108  extend a designated distance from the surface of the support members, and each have a generally trapezoidal shape. As shown in  FIG.  7   , a plurality of panels  110  each have a flat inner surface  112  and are attached to the frame  104  by aligning slots  114 , i.e., through-holes, formed in the panels with corresponding tabs  108  on the support members of the frame as shown in  FIG.  17   . The connection of the tabs  108  with the slots  114  on the panels  110  enables the panels to be easily aligned with and attached to the frame  104 . After the panels  110  are attached to the frame  104 , the panels are secured to the frame by welding the tabs  108  to the panels  110  using a welding material. As shown in  FIG.  7   , the support members  106  of the frame  104  are positioned at a designated angle relative to a central longitudinal axis  116  of the hopper  44 , and preferably at an angle of sixty degrees, so that the panels  110  of the lower hopper units  98  are also at an angle of sixty degrees, which promotes the funneling of a raw material toward the hopper outlet  52  while preventing the raw material from sticking to or residing on the inner surfaces of the panels  110 . It should be appreciated that the support members  106  and the panels  110  may be positioned at any suitable angle relative to the longitudinal axis  116  of the lower hopper units  98 . 
     As shown, a plurality of air supply devices  118  are attached to the inner surfaces  112  of the panels  110  of the lower hopper units  98  and oriented transverse to the longitudinal axis of the panels  110 . The air supply devices  118  are spaced apart along the length of the panels  110  and emit or blow pressurized air on the inner surfaces  112  of the panels  110  of the lower hopper units as described below. In this embodiment, the lower hopper units  98  are attached to each other preferably by connectors such as bolts, washers and nuts or other suitable connectors so that welding at a site is not required. It should be appreciated that the lower hopper units  98  may also be connected together by welding or any suitable attachment method. 
     Referring to  FIGS.  8  and  10 - 17   , the middle hopper units  100  are pre-fabricated modular units that each include a frame  122  made with a plurality of support members  124  that are attached together by welding or another suitable attachment method. The frame  122  is preferably made of a metal, such as stainless steel, but may be made with a composite material, or any suitable material or combination of materials. As shown in  FIGS.  8  and  10   , an inner structure  126  of the frame  122  includes a plurality of panel brackets  128  that a spaced from each other and have an inner end  130  attached to one of the support members  124  and an outer end  132  having a surface  134  configured at an angle relative to the central longitudinal axis  136 , where the angle is preferably sixty degrees as described above. More specifically, the inner ends  130  of the brackets  128  each have an upper arm  138  and a lower arm  140  that define a square-shaped opening  142 , where the upper and lower arms extend over the upper and lower surfaces of one of the support members  124  of the frame  122  so that the support member fits into the opening  142  and the bracket contacts at least three sides of the support member as shown in  FIG.  15   . In the illustrated embodiment, the upper and lower arms  138 ,  140  each have a connector hole  144  that aligns with corresponding holes  146  on the frame brackets  148  of the support members  124 . In this way, the brackets  128  may be connected to the frame brackets  148  by connectors, such as bolts, washers and nuts, or screws, or welded to the frame brackets. Similarly, the support members  124  are preferably welded to the brackets  128  to further secure the brackets  128  to the frame  122 . 
     Referring to  FIGS.  11 ,  13  and  15   , a panel frame  150  includes a plurality of support members  152  that are attached together by welding or other attachment method, and support panels  110  of the hopper  44 . The panel frame  150  is preferably made of a metal, such as stainless steel, but may be made with a composite material, or any suitable material or combination of materials. In the illustrated embodiment, the support members  152  of the panel frame  150  each include through-holes  154  that align with corresponding through-holes  156  formed in the outer ends  132  of the brackets  128  as shown in  FIG.  15   . In this way, the support members  152  and the panel frame  150  are secured to each other by bolts, washers and nuts, and enable the panel frame to be easily and quickly aligned and secured on the frame  122 . After the panel frame  150  is attached to the frame  122 , the outer ends  132  of the brackets  128  may be further secured to the panel frame by welding the support members  152  to the brackets  128  using a welding material or by another suitable attachment method. 
     Referring to  FIGS.  12 ,  16  and  17   , panels  110  are secured to the panel frame  150  by aligning slots  114  formed in the panels with corresponding tabs  108  on the outer ends of the brackets  128 . The connection of the tabs  108  to the slots  114  in the panels  110  enables the panels to be quickly and easily positioned on the panel frame  150  and initially secured in place by tack welding. Additional welding is performed on the tabs  108  and slots  114  to fix the panels  110  on the panel frame  150 . Similar to the lower hopper units  98 , the middle hopper units  100  include a plurality of air supply devices  118  that extend transversely to the longitudinal inner surfaces of the panels  110 . As shown, the air supply devices  118  are spaced apart and are configured to receive and emit pressurized air directed at the inner surfaces of the panels  110 . In this embodiment, the middle hopper units  100  are attached to each other preferably by connectors such as bolts, washers and nuts, or other suitable connectors so that welding at a site is not required. It should be appreciated that the middle hopper units  100  may also be connected together by welding or any suitable attachment method. 
     Referring to  FIG.  9   , the upper hopper units  102  have a similar construction to the middle hopper units  100 , and include a frame  158  made with support members  160  that are interconnected by welding. The frame  158  is preferably made of a metal, such as stainless steel, but may be made with a composite material, or any suitable material or combination of materials. In this embodiment, a lower part  162  of the frame  158   includes a plurality of the spaced brackets  164  that are attached to a lower support member  166  as described above. The outer ends  168  of the brackets  164  have a surface  170  configured at an angle relative to the central longitudinal axis  172  of the hopper  44 , where the angle is preferably sixty degrees, but may be any suitable angle. A plurality of lower panels  174  are secured to the brackets  164  as shown in  FIGS.  16  and  17    as described above. The lower panels  174  are positioned at an angle of sixty degrees corresponding to the angle of the surfaces of the outer ends  168  of the brackets  164  and to the angled panels  174  of the middle hopper units  100  and the lower hopper units  98 . The upper part  176  of the frame  158  is vertically oriented and a plurality of upper panels  178  are secured to this part of the frame  158  by the tabs  108  and slots  114  shown in  FIGS.  16  and  17   . After the upper hopper units are assembled, the upper hopper units  102  are attached to each other preferably by connectors such as bolts, washers and nuts or other suitable connectors so that welding at a site is not required. It should be appreciated that the upper hopper units  102  may also be connected together by welding or any suitable attachment method. 
     The roof structure  46  of the modular hopper assembly  40  includes pre-fabricated side roof units  180  as shown in  FIGS.  18 A and  18 B , and pre-fabricated central roof units  182  as shown in  FIGS.  19 A,  19 B and  19 C . The side roof units  180  each include a frame  184  made with support members  186  that are interconnected by welding or another suitable attachment method. A plurality of base panels  188  are attached to a lower surface  190  of the frame  184  and a plurality of outer panels  192  are attached to an upper surface  194  of the frame  184 . The base panels  188  and the outer panels  192  are each attached to the support members  186  of the frame  184  by aligning slots  114  in the outer panels  192  and base panels  188  with integrally formed tabs  108  on the support members  186  of the frame as described above. Similarly, a plurality of side panels  196  are attached to the perimeter of the frame  184  by the connection of the tabs  108  on the support members  186  with the slots  114  in the side panels. As shown in  FIG.  18 A , the outer panels  192  form a generally flat upper surface  198 , the outer side panels  196   a  are slanted at an angle and the inner side panels  196   b  are vertically oriented. A bottom surface  200  of each side roof unit  180  includes a connection frame  202  formed with support members  204  that enable the side roof units  180  to be attached to the top surfaces of the upper hopper units  102  by welding or another suitable attachment method. In the illustrated embodiment, one or more of the side roof units  180  include inlet ports  206  and one or more air vents  208 . It should be appreciated that the side roof units  180  may include one or a plurality of the inlet ports  206  and air vents  208 . 
     Referring to  FIGS.  19 A,  19 B and  19 C , the roof structure  46  includes one or more central roof units  182  that are each connected between the side roof units  180  as described below. Each of the central roof units  182  includes a frame  210  made with a plurality of support members  212  that are interconnected in a grid pattern by welding. A plurality of outer panels  214  are attached to an upper surface  216  of the frame  210  by the tab and slot connections described above. Similarly, end panels  218  are connected to the opposing ends of the frame  210  by the tab and slot connections. As shown, the outer panels  214  form a generally flat surface  220  and the end panels  218  are positioned at an angle relative to the outer panels. A plurality of base panels  222  are attached to a lower frame  224  where the lower panels are attached to an upper surface  226  of the frame  224  by the tab and slot connections described above. In this embodiment, the central roof unit  182  includes an air vent  228  but may include one or a plurality of air vents or one or more access panels to the interior of the hopper  44 . After being assembled, each of the central roof units  182  are attached to the upper surface of the upper hopper units  102  by welding or another suitable attachment method. In this embodiment, the panels and the support members of the side roof units and the central roof unit or units are preferably made of a metal, such as aluminum, but may be made out of any suitable material or combination of materials. Preferably, the roof structure (the top of the hopper) has a length of at least 22 feet by a width of at least 22 feet to provide a stable, safe platform for equipment placed on the roof structure. It should be appreciated that the roof structure may have any suitable length and width. 
     Referring to  FIGS.  26  and  27   , in the above embodiment, an air cleaning system  228  is built into the hopper  44  is configured to remove dust, raw material and other material debris that may remain on the inner surfaces of the hopper. Cleaning the inner surfaces of the hopper  44  is critical for maintaining material quality and integrity and preventing cross contamination between different raw materials stored in the hopper. Further, larger hoppers are typically cleaned manually, which requires a person to access the interior of the hopper, which can be time consuming and dangerous. The present air cleaning system  228  fully automates the cleaning process, which overcomes the above issues, and cleans the inner surfaces of the hopper  44  in a much shorter amount of time, i.e., minutes instead of hours. 
     In this embodiment, the air supply devices  118  of the air cleaning system  228  are mounted on the inner surfaces of the panels of the hopper  44  and each have a square cross-sectional shape that defines a hollow interior space  230 . Each of the air supply devices  118  are mounted on the inner surfaces of the hopper  44  so that there are no flat surfaces on the air supply devices for collecting dust, raw material or other debris. Further, the air supply devices  118  are each connected to a pressurized air source that may be located on the top surface of the roof structure  46  or another suitable location. A plurality of spaced openings or nozzles  232  are formed in a bottom surface  234  of the air supply devices  118  and are configured to direct pressurized air from the hollow interior space  230  at the inner surfaces of the panels of the hopper  44  to help clean dust, raw materials and other debris from the inner surfaces. Additionally, the topmost air supply device  118   a  in the upper hopper units  102  includes a top surface  236  with openings or nozzles  232  directed toward the ceiling of the hopper  44  to help remove and clean raw material from the ceiling of the hopper. In another embodiment, the topmost air supply device  118   a  includes openings or nozzles that are on the upper and lower surfaces of the air supply device to direct pressurized air toward the ceiling and toward the inner surfaces of the hopper. It should be appreciated that one of the air supply devices or a plurality of the air supply devices  118  may direct pressurized air toward the ceiling of the hopper. In this embodiment, the air supply devices  118  automatically direct pressurized air at the inner surfaces and ceiling of the hopper  44  at a designated time or times. In an embodiment, the air supply devices  118  are coupled to a timer associated with a controller or processor that sends a signal to the air supply devices to operate at the designated time or times. In another embodiment, the air supply devices  118  are coupled an integrated control system in a control room and controlled by an operator 
     During a cleaning cycle, pressurized air or compressed air is introduced into the air supply devices  118  by an air solenoid valve. The pressurized air is directed out of the openings  232  in the air supply devices at the hopper’s interior surfaces, thereby blowing dust, raw material and other debris downward toward the outlet  52 . Similarly, at least the topmost air supply device  118   a  directs pressurized air at the ceiling of the hopper  44  to dislodge dust and other materials from the ceiling. The air supply devices  118  are supplied with pressurized air from one or more air manifolds, where the air manifolds allow for air accumulation close to the air cleaning system  228  and are part of the air distribution system in which air solenoid valves feed the air supply devices. As described above, the panels (inner walls) of the hopper  44  are configured at an angle of sixty degrees, which is sufficient for mass flow of most raw materials and facilitates thorough cleaning of dust, raw materials and other debris from the inner surfaces of the hopper. 
     In operation, a valve on the outlet  52  to the hopper  44  is closed and a vacuum pump or air blower is started. One or more valves on the ceiling (roof structure) of the hopper  44  are opened to allow air to be pulled through the hopper from filtered vents located at the top of the hopper. Next, the air supply devices  118  are sequentially actuated from the top to the bottom of the hopper  44  to dislodge dust and other materials from the inner surfaces of the hopper and into the vacuum air stream toward the outlet  52 . This cleaning cycle may be performed repeatedly during each cleaning of the hopper  44  as needed to sufficiently clean the interior of the hopper and meet the level of cleaning required to prevent cross contamination of the raw materials stored in the hopper. Upon completion of the cleaning process, the vacuum pump and/or air blower is shut off and the outlet  52  is re-opened. 
     Referring to  FIGS.  20 - 25   , the pre-fabricated modular units of the modular hopper assembly  40  described above are configured to be shipped globally via standard and high cube forty foot ISO shipping containers on transportation vehicles, such as flatbed trailers or railcars, or dry vans. No crating or excessive dunnage (shipping containers or packaging) is required to safely ship the modular units to a site. Further, the modular units  98 ,  100  and  102  are configured to be at or below regulatory weight limitations for shipping containers and/or the vehicles that transport the modular units. In this way, the modular units  98 ,  100  and  102  are designed and constructed in a size that maximizes shipping efficiency, expedites and facilitates assembly at a site, and enables assembly in buildings, or other structures, that do not have large ports of access and without forming or cutting openings in a part of a building structure such as in a wall or roof of a building. The modular configuration of the hopper units also allows for easy modification of portions of the hopper assembly  40  without changing or replacing the entire hopper assembly. 
     After the modular units  98 ,  100  and  102  for the hopper assembly  40  are shipped to a site, the modular units are assembled to construct the hopper assembly  40  at the site. In the illustrated embodiment, the modular hopper assembly  40  is constructed at the site using a “bottom up” construction method in which the upper parts of the hopper assembly are constructed first down to the base, which is constructed last. 
     Assembly or construction of the embodiment of the hopper assembly  40  shown in  FIG.  1    initially includes lifting the side roof units  180  using a suitable machine, such as a 10,000 pound capacity extended reach forklift, and placing the side roof units on the top of the upper hopper units  102  as shown in  FIG.  22   . Similarly, the central roof unit  182  is lifted and placed on opposing central walls  183  of the upper hopper units  102 , where the central walls  183  are constructed as described above for the upper hopper units. The roof units  180 ,  182  are secured to the upper hopper units  102  and the central walls by bolts, washers and nuts or with any suitable connectors. The upper hopper units  102  are then attached together as shown in  FIG.  23    by similar connectors to form the upper structure of the hopper assembly  40 . A railing  185  is attached to the roof structure  46 , and any equipment, such as an air blower or vacuum generator, is placed on and secured to the roof structure while the working height of the hopper assembly  40  is safe and easy to access. It should be appreciated that the railing  185  and any other equipment may be secured to the roof structure before or after the roof structure and upper hopper units are assembled together. 
     Next, two or more high capacity forklifts each with 45,000 to 55,000 pound lifting capacity, are positioned on opposing sides of the assembled upper hopper and roof units  102 ,  180 ,  182 , and used to raise the above assembled structure to a designated height to accommodate the next level of the modular units of the hopper assembly  40 . As shown in  FIG.  23   , the two middle hopper units  100  ( FIG.  8   ) and two opposing middle wall units  123  constructed as shown in  FIG.  18    and described above, are individually moved into position below the raised assembled structure including the upper hopper units and roof units, using conventional forklifts, such as forklifts having 5,000 pound lifting capacity. The middle hopper units  100  and the middle wall units  123  are attached together using connectors, such as bolts, washers and nuts, or other suitable connectors, to form the middle structure of the hopper assembly  40 . The upper structure is aligned with the middle structure and then the upper structure is lowered onto the middle structure and connected together using suitable connectors as described above. 
     After the upper structure is secured to the middle structure, the assembled upper and middle structures are raised to a designated height by forklifts or similar equipment as described above. Next, the assembled lower hopper units  98  are aligned with and connected to the bottom of the portion of the middle hopper units  100  using connectors, such as bolts, washers and nuts. Also, one of the base units  50 , namely the third base unit  50   c  in this embodiment, is assembled and positioned under and aligned with the assembled upper and middle structures. The assembled upper and middle structures are then lowered onto the upper surface of the third base unit  50   c  and connected to the third base unit using suitable connectors, as shown in  FIGS.  24  and  25   . 
     In this embodiment, the base  42  includes three base units  50   a ,  50   b  and  50   c  to raise the hopper  40  to a desired height. It should be appreciated that one or a plurality of the base units  50  may be assembled and used in the hopper assembly  40  depending on the desired final height of the hopper. As shown in  FIG.  25   , the second base unit  50   b  is assembled and positioned under the third base unit  50   c  attached to the upper and middle structures. Once aligned, the assembled structure is lowered onto and connected to the upper surface of the second base unit  50   b  using suitable connectors. Next, the assembled structure including the upper and middle structures and the second and third base units  50   b ,  50   c  is raised to a designated height and four of the base support members  48  are positioned at respective corners of the assembled structure. The assembled structure is then lowered onto the four base support members  48 . As shown in  FIGS.  20  and  21   , the support members  48  of the base units  50  each include planar upper and lower plates  54  and  56  that are easily aligned and connected to the upper and/or lower plates  54  and  56  of an adjacent support member using suitable connectors. Further, the lower plates  56  of the support member  48  of the base unit  50   c  are attached to base plates  76 . After the support members  48  are connected to the assembled structure and the base plates  76 , the base plates on the bottom support members  48  are secured to the floor or ground of the site by connectors such as bolts. After being secured to the floor or ground, the construction of the hopper assembly  40  is complete as shown in  FIG.  1   . 
     In the above embodiment, the modular units of the modular hopper assembly  40  are configured to be independent structures that may be shipped, handled and positioned easily at a site. To achieve this, the modular units do not have individual flange components, such as on a support member  48 , so that the support members  48  are unitized into a singular flange connection. As such, the fabrication of the modular units is easier and faster than conventional hoppers, and easier to handle and transport to a site. 
     Furthermore, the structural members of the modular units do not have any angular cuts. Instead, the cuts made in the structural members are all at an angle of ninety degrees, which makes processing and assembly quicker and less expensive than complex cuts. Also as described above, welding of the modular units is performed in the pre-fabrication process at a manufacturing location and not at a designated assembly site, which helps to reduce material and labor costs and enable the hopper assembly to be assembled quickly and efficiently. 
     In the above embodiment, the support members and other structural components of the modular units of the hopper assembly  40  are first assembled into the modular units and then primed and painted. Completing the assembly, priming and painting of the modular units at a manufacturing site before shipment to a site or sites, save significant time and costs associated with shipping and assembly of the modular hopper assembly  40 . Furthermore, the assembly process may be reversed if the hopper assembly  40  needs to be disassembled and moved to another location, which saves time and costs. 
     While particular embodiments of the present hopper assembly are shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.