Abstract:
A powdery material removal and recovery system comprises a distribution apparatus ( 1 ), a blower unit ( 2 ), a vacuum unit ( 3 ), a recovered powder receiving hopper ( 4 ), a powder sifter ( 5 ) and a conveyor ( 6 ). The vacuum unit ( 3 ) sucks material particles from the surface of boards passing along conveyor ( 6 ) below and transfers the material to receiving hopper ( 4 ). Air from the blower unit ( 2 ) is expelled through a pressure chamber of the distribution apparatus ( 1 ) onto the surface of the boards below so that any remaining remnants of particles are dried and dislodged and can then be removed via the outer duct compartments ( 108, 110 ). Recovered material deposited into the receiving hopper ( 4 ) may then be transferred to the powder sifter ( 5 ) for sifting and reuse.

Description:
This application claims the benefit of PCT/IE2006/000055, filed 9 May 2006 and of Ireland patent application number S2005/0297, filed 10 May 2005. 
     TECHNICAL BACKGROUND 
     The present invention relates to a system for dislodging and removing powdery residues from handling and conveying systems. 
     BACKGROUND ART 
     In the manufacture of certain edible products such as bread and the like, dough is placed onto a board and is left in a proving chamber for a specific time to prove. Prior to receiving the dough, the boards, which are sometimes referred to as “peel-boards”, are pre-sprinkled with a powdery material, such as semolina flour, in order to assist the eventual release of the dough. After the removal of the dough, residual semolina flour remains on the peel-boards. It is normal practice to remove this flour using a vacuum system. However experience has shown that removal and recovery of the flour is often incomplete as some flour may remain adhered to the board due to ambient humidity, the moisture of the dough or moisture generated over the proving process, which typically has a duration of 2-6 hours. 
     It is therefore an object of the invention to alleviate the disadvantages associated with the prior art. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides a powdery material removal and recovery means comprising a distribution head having vacuum means for drawing material from a surface by suction and for transferring the material to at least two recovery chambers and onwards to a recovery hopper and an air distribution means for directing air onto the surface via a pressure chamber to assist in the removal of the powdery material by the vacuum means, the recovery chambers and the pressure chamber formed by spaced apart baffles extending from a position level with an upper edge of a top opening to a position level with a lower edge of a bottom opening of said distribution head. 
     In another aspect, the present invention provides a powdery material removal and recovery apparatus, comprising a distribution head with sealed edges and a pair of interior spaced-apart baffles that define a pressure chamber and a pair of recovery chambers in opposing relation lateral of the pressure chamber, the baffles extending from a position level with an upper edge of a top opening to a position level with a lower edge of a bottom opening of the distribution head. An inwardly tapered funnel-shaped lower section of the distribution head forms a restricted nozzle opening at the bottom which nozzle opening communicates with the recovery chamber and with the pressure chamber. A vacuum means provides for drawing material from a surface by suction and for transferring the material to the pair of recovery chambers and onwards to a recovery hopper. An air distribution means provides for directing air onto the surface via the pressure chamber to assist in the removal of the powdery material by the vacuum means. Means provides for positioning the distribution head selectively relative to the surface. 
     In another aspect, the present invention provides a powdery material removal and recovery apparatus comprising a distribution head having vacuum means for drawing material from a surface by suction and for transferring the material to a recovery chamber and onwards to a recovery hopper and an air distribution means for directing air onto the surface via a pressure chamber to assist in the removal of the powdery material by the vacuum means, and an adjustable bracket to which the distribution head mounts, the adjustable bracket operable to allow altering a clearance between the distribution head and the surface. 
     In another aspect, the present invention provides a powdery material removal and recovery apparatus comprising a distribution head having vacuum means for drawing material through a bottom opening from a surface by suction and for transferring the material to a recovery chamber and onwards to a recovery hopper and an air distribution means for directing air onto the surface via a pressure chamber having a bottom opening to assist in the removal of the powdery material by the vacuum means, the distribution head comprises an inwardly tapered funnel-shaped lower section that forms a restricted nozzle opening at the bottom, and a base plate covering the nozzle opening in the distribution head and having a plurality of slots arranged in spaced apart rows so that the respective bottom openings of the distribution head chambers are reduced in aperture. 
     In another aspect, the present invention provides a powdery material removal and recovery apparatus comprising a distribution head having vacuum means for drawing material through a bottom opening from a surface by suction and for transferring the material to a recovery chamber and onwards to a recovery hopper and an air distribution means for directing air onto the surface via a pressure chamber having a bottom opening to assist in the removal of the powdery material by the vacuum means, and a removable lid that comprises a depending skirt around its edges that forms a lip so that when positioned on the distribution head, an inner surface of the lip contacts a respective coincident outer edge of the distribution head to form a seal, and the lid includes means for connecting suction or pressuring means to the recovery chamber and the pressure chamber respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic diagram of a recovery system embodying the invention; 
         FIG. 2   a  is an exploded view of a distribution head of the recovery system of  FIG. 1 ; 
         FIG. 2   b  is a plan view from above of the distribution head; 
         FIG. 2   c  is a sectional elevation of the distribution head; 
         FIGS. 3   a  and  3   b  are a plan view and an end elevation respectively of a base plate of the distribution head; and 
         FIG. 4  is an isometric illustration of the adjustable bracket and the distribution head. 
     
    
    
     DETAILED DESCRIPTION 
     As discussed in detail below, the present invention provides a powdery material removal and recovery means comprising a distribution head having vacuum means for drawing material from a surface by suction and for transferring the material to a recovery chamber and onwards to a recovery hopper and an air distribution means for directing air onto the surface via a pressure chamber to assist in the removal of the powdery material by the vacuum means. 
     Typically, the surface is that of a receiver such as a board, and the board travels on a conveyor located beneath the distribution head. In use, the recovery chamber and the pressure chamber are located transverse to the surface of the board in the direction of relative travel between the distribution head and the board. 
     Preferably the board comprises a peel-board. 
     Ideally the distribution head of the recovery means comprises at least two recovery chambers. 
     Conveniently, the distribution head comprises a boxed channel section with sealed edges and is open at the top and bottom. 
     Advantageously, the distribution head comprises an inwardly tapered funnel-shaped lower section that forms a restricted nozzle opening at the bottom. 
     Preferably, the at least two recovery chambers of the distribution head formed by spaced apart baffles extending from a position level with the upper edge of the top opening of the distribution head to a position level with the lower edge of the bottom opening of said distribution head. 
     In a preferred arrangement, the pressure chamber is formed by a baffle extending from a position level with the upper edge of the top opening to a position level with the lower edge of the bottom opening of said distribution head. 
     Preferably, the pressure chamber is located between the two recovery chambers. 
     Ideally, the bottom opening of the distribution head is covered by a base plate having a plurality of slots arranged in spaced apart rows so that the respective bottom openings of the distribution head chambers are reduced or restricted in aperture. 
     The distribution head guides pressurised air onto the surface of a board in order to disturb loose powdery material residing on the board surface and to dislodge any material that may be adhered to the board surface. This assists the removal of all powdery residues and clumped material from the board surface to the recovery chamber or chambers. Blowing pressurised air on to the board also facilitates the drying of any damp powdery material on the board which further assists its removal from the board surface by the vacuum means. 
     Upon removal of the floury residues, the boards are available for re-use. Prior to receiving new dough for proving, boards may be re-sprinkled with sifted semolina which can be fresh material or material recovered from the hopper. The removal of clumped powder clusters from the previous cycle and the provision of a freshly sprinkled coating of semolina on the boards ensures that bread products are consistently and easily removable from the boards and are produced with smooth surfaces free of clumped baked-on semolina flour. 
     Advantageously, the distribution head is mounted adjacent the board by an adjustable bracket which allows the clearance between the distribution head and the board surface to be altered. 
     In a preferred arrangement the distribution head includes a removable lid. This provides access to interior duct compartments of the distribution head for cleansing and maintenance purposes. 
     The removable lid is ideally provided with a depending skirt that forms a lip sized so that when positioned on the distribution head, the inner surfaces of the lip contact the coincident outer edges of the distribution head to form a seal. 
     The invention also provides a dough handling system incorporating the material removal and recovery means described above. 
     The invention will now be described more particularly with reference to the accompanying drawings, in which are shown, by way of example only, one embodiment of a material recovery system according to the invention. 
     Referring initially to  FIG. 1 , a powdery material removal and recovery means according to the invention comprises a distribution apparatus  1 , a blower unit  2 , a vacuum unit  3 , a recovered powder receiving hopper  4 , a powder sifter  5  and a conveyor  6 . In this example, the powdery material is semolina flour, but it will be appreciated that the system may equally be employed with other powdery substances. The distribution apparatus includes a distribution head  100 , a removable lid  200 , a base plate  300  and a mounting (system) bracket  400 . 
     The distribution head  100  comprises a container having two substantially spaced apart parallel end walls  101 ,  102  and two spaced apart parallel side walls  103 ,  104 . Each side wall  103 ,  104  is formed from an initially flat rectangular stainless steel sheet that is bent in a straight line along its length to create two flat sections such that an upper flat section which may be placed substantially vertically with a lower flat section being angled obtusely inwardly. Positioning the two side walls  103 ,  104  in this manner and connecting them to the end walls  101 ,  102  provides a boxed channel section with sealed edges that is open at the top and has an inwardly tapered funnel-shaped lower section that forms a substantially rectangular restricted nozzle opening  105  at the bottom. 
     Referring to  FIG. 2   c , within the confines of the distribution head walls three separate duct compartments  108 ,  109  and  110  are formed by the provision of two spaced apart baffles  106 ,  107  that are attached perpendicularly at each end to the end walls and that extend from a position level with the upper edge of the top opening to a position level with the lower edge of the bottom opening  105 . The bottom nozzle opening  105  is thus divided into three separate parallel narrow elongate orifices. The central compartment  109  is a pressure chamber and the outer compartments  108  and  110  are vacuum chambers. The baffles  106 ,  107  are formed using the same process used for the side walls described herein. However, the lower inwardly bent sections of the baffles are at a shallower angle than those of the side walls. The vertical upper sections of the baffles are spaced parallel to the side walls  103 ,  104 . 
     Referring to  FIGS. 2   a  and  2   b , a substantially rectangular removable lid  200  is constructed from sheet stainless steel material and has a depending skirt that forms a lip  201  that extends downwardly around its entirety. When positioned over the top opening of the distribution head  100  the underside of the lid rests on the upper edges of the distribution head walls  101 ,  102 ,  103 ,  104  and the baffles  106 ,  107  and the inner surfaces of the lip  201  contact the coincident outer edges of the distribution head walls to form a seal. Fastening of the lid to the distribution head  100  is achieved using a plurality of draw clamp latches  111  mounted to the distribution head side walls  103 ,  104  that engage with corresponding latch keepers  211  connected to the outer surface of the lip  201 . 
     The lid has four circular holes arranged to provide two pressurized air inlet ports  203 ,  204  for compartment  109 , a vacuum outlet port  208  to compartment  108  and a vacuum outlet port  210  to compartment  110 . Bolted directly about the bore of each hole is a cylindrical and flanged pipe tail section  212  that protrudes upwards from the lid upper surface to facilitate connection to conduits that carry air or vacuum pressure to the respective compartments. Connection of the conduits to the pipe tail sections may be made using jubilee clips or other suitable removable fasteners. Typically, the conduits will be constructed as a flexible hose with clamps or clips provided to connect the hose to a pipe tail section. 
     Referring to  FIGS. 3   a  and  3   b , the base plate  300  comprises a covering that fits flush over the bottom nozzle opening  105  of the distribution head when connected by welding to the lower edges of end walls  101 ,  102  and side walls  103 ,  104 . It comprises a flat elongate stainless steel sheet that contains a plurality of substantially rectangular slots arranged in two spaced apart rows  308 ,  310 , each row being provided to either side of, and parallel to, a single long central slot  306  as shown. The spacing between the rows and the central slot is of a sufficient distance such that connection of the base plate to the bottom ends of the baffles  106 ,  107  can be made. The central slot  306  of the base plate reduces the aperture of the central orifice of the nozzle opening  105  that corresponds to central compartment  109 . Rows  308  and  310  restrict the outer orifices of the nozzle  105  that correspond to the outer compartments  108  and  110  respectively. In one embodiment the slots of rows  308  and  310  are approximately 45 mm in length and 8 mm in width with an end-to-end spacing of approximately 5 mm. Other dimensions will be suitable and selected for other systems. 
     Referring to  FIG. 4 , the distribution head  100  is mounted on a bracket  400  that comprises two spaced apart arms  401 ,  402  hinged at their distal ends and each pivotally mounted on a pivoting mechanism  421 ,  422 , respectively, such that the clearance between the distribution head base plate  300  and the conveyor  6  can be adjusted upon actuation of a handle bar  418  that extends between levers  416 ,  417  that are connected to the respective pivoting mechanism of each arm. 
     The respective proximal ends of the arms  401 ,  402  are each connected by a plurality of bolts to the lower sections of the distribution head end walls  101 ,  102 . The arms each extend from the distribution head towards distal upright members  403 ,  405  which are each bolted at their bases to outer rails  601 ,  602  of a conveyor system frame. Pins  407 ,  408 , each provided with an axially aligned threaded hole at one end and an axially aligned threaded shank at the other, extend between the respective arms  401 ,  402  and upright members  403 ,  405 . Connection of the arms  401 ,  402  to the pins  407 ,  408  is effected by bolts  419  that extend through apertures in the arms  401 ,  402  to engage with the threaded holes of the pins  407 ,  408 , respectively. The threaded shanks of the pins  407 ,  408  each extend through apertures provided through the upright members  403 ,  405 , respectively, and are fastened at their free ends by lock-nuts  420 . In this arrangement, upright members  403 ,  405  and pins  407 ,  408 , provide a hinge mechanism whereby the arms  401 ,  402  raise and lower the distribution head  100 . 
     Control over the raising and lowering of the distribution head  100  is facilitated by mechanisms  421 ,  422 , each connected to the respective arms at a position intermediate the proximal and distal ends. Referring to mechanism  421  operating on the arm  401 , an upright member  404 , bolted at its base to the outer rail  601  of the conveyor system frame, supports a fulcrum pin  409 . The pin  409 , which is secured at its outer end by a lock-nut  423 , extends inwardly to contact a disk  411  such that their respective axes are in alignment. A bolt (not shown) extending through an aperture formed in the rear of the disk  411  and engaging with an axially threaded hole that is provided at the inner end of the pin  409 , fastens the disk  411  and pin  409  together. A second pin  413 , radially off-set from pin  409 , extends from the disk  411  through a slot  415  that is provided through the arm  401 . The pin  413 , which has threaded ends, is secured at both ends by hexagonal nuts (not shown) and the mechanism is assembled such that when positioned through the most distal end of the slot  415 , the central axis of pin  413  lies vertically above the central axis of pin  409 , as shown in  FIG. 4 . In this configuration the distribution head  100  is raised to its highest position and the lever  416  extends distally from the disk  411  to which it is connected at an angle such that the underside of the handle bar  418 , which spans perpendicularly across the conveyor system to connect with lever  417  on the opposing side, is clear of the arms  401 ,  402  below. Connection of the lever  416  to the disk  411  is effected by welding. 
     To lower the distribution head, an operator raises the handle bar  418  so that the inertia of the mechanism is overcome and the disks  411 ,  412  rotate about fulcrum pins  409  and  410 , respectively. The rotation of the disks imparts motion to the off-set pins  413 ,  414  which is translated into forward and downward motion components by the slots  415  and  416 , along which the pins  413 ,  414  are able to slide, respectively. In turn, this moves the arms  401 ,  402  downwards thus lowering the distribution head. Lugs  431 ,  432  projecting from arms  401 ,  402 , respectively, prevent the distribution head from descending below a predetermined working height, determined by pillars  441 ,  442  upon which the lugs impinge. The pillars  441 ,  442 , which are height-adjustable, have threaded proximal ends. Each pillar  441 ,  442  is connected to the conveyor system frame by an upper nut and a lower lock-nut (only upper nuts  443  are shown) that are located above and below the outer rails  601 ,  602  of the conveyor system frame, respectively. By altering the position of the upper nuts  443  along the pillars  441 ,  442 , the height to which the pillars  441 ,  442  extend above the surface of the outer rails  601 ,  602  may be varied. By using the lower lock-nuts (not shown) to fasten the pillars  441 ,  442  to the underside of the outer rails  601 ,  602 , the desired height is thus locked in position. 
     The use of the apparatus for removing powdery residue, such as semolina flour, will now be described. 
     The blower unit  2  is connected via a conduit  21  to the inlet ports  203 ,  204  of the central chamber  109  of the distribution head  100 . A vacuum unit  3  is connected, via a recovered semolina receiving hopper  4 , by a conduit  31  to the outlet ports  208 ,  210  of the outer chambers  108  and  110  respectively. The distribution head is mounted by a bracket  400  so as to be positioned upright above a conveyor  6  that conveys peel-boards. The distribution head is mounted such that the base plate  103  is oriented transversely across a longitudinal axis of the peel-boards in the direction of travel of the conveyor and is situated at a distance of ideally less than 10 mm from the surface of the peel-boards below. With the vacuum unit in operation, semolina flour is vacuumed from the entire surface of the peel-boards as they travel on the conveyor through the outer slots  308 ,  310  of the base plate  300  into the outer chambers of the distribution head. From these chambers the flour is sucked further through the outlet ports  208 ,  210  via conduit  31  to the remotely located recovered semolina receiving hopper  4 . Simultaneously with the vacuuming operation, air from the blower  2  unit enters the central chamber of the distribution head and is ducted downwards towards the nozzle opening  105  at the bottom. The pressurised air is expelled through the central slot  306  of the base plate  300 . The pressurised air impinges on the peel-board surface and dislodges any remnants of flour that may be remaining. For more complete flour recovery, these disturbed particles are vacuumed into the outer chambers of the distribution head and up to the recovered semolina receiving hopper as previously described. 
     While the system has been described such that the distribution head  100  is in a fixed position so as to remove powder from the boards passing beneath it on a conveyor, it will be appreciated that other configurations are possible. For example, the distribution head may be located on a carriage which acts to move the distribution head over stationary or moving boards. Additionally, any desired number of vacuum chambers may be provided. 
     It will of course, be understood that the invention is not limited to the specific details described herein, which are given by way of example only and that various modifications and alterations are possible within the scope of the invention as defined in the appended claims.