Abstract:
A continuously operating magnetic particle separating machine includes an inlet for receiving a material having magnetic particles mixed therein, an outlet for discharging the material after the magnetic particles have been separated therefrom, a first flow path extending between the inlet and the outlet, a first magnetic element positionable in the first flow path, a second flow path extending between the inlet and the outlet, and a second magnetic element positionable in the second flow path. The separating machine includes a control system including a diverter valve switchable between a first position for directing the material through the first flow path and a second position for directing the material through the second flow path, whereby the switching frequency of the diverter valve is responsive to a concentration of the magnetic particles in the material.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is directed to separating and/or filtering machines and is more particularly directed to metallic particle separating machines. 
       BACKGROUND OF THE INVENTION 
       [0002]    Metallic particles are often present in materials such as spices, flour, sugar, chemicals and pharmaceutical ingredients. Before the materials may be further processed, the metallic particles must be removed. In many instances, magnetic forces or magnets may be used for removing the metallic particles from the material. The dry material, with the metallic particles removed, may then be further processed. 
         [0003]    There have been a number of advances in metallic particle separating machines. For example, U.S. Pat. No. 4,457,838 to Carr discloses a self-cleaning magnetic separator for powered plastic and metal materials. The magnetic separator includes an inlet, a base plate and side plates. A plurality of vertically spaced staggered rows of laterally spaced pilot tubes are secured to the side plates to define a circuitous material falling path. An upright tube clearance plate is arranged intermediate the side plates and has a corresponding plurality of vertically spaced rows of laterally spaced apertures, oversized with respect to and loosely receiving the tubes defining clearance apertures. The clearance plate defines on one side an upright plastic feed chamber having an outlet in the base plate. An upright wiper plate is arranged between the clearance plate and one side plate having a corresponding series of apertures snugly receiving the tubes and defining with the adjacent side plate an upright metal feed chamber having an outlet. The elongated magnetic assembly is slidably mounted upon and intermittently reciprocal within each tube and is normally positioned within the plastic feed chamber. Falling particles of plastic cascade over the tubes within the plastic feed chamber for delivery through its outlet, however, the metal particles mixed in with the plastic particles adhere to the tubes. Upon intermittent retraction of the magnetic assemblies, the wiper plates strip the metal particles from the tubes and the metal particles fall within the metal feed chamber and through its outlet. 
         [0004]    U.S. Pat. No. 4,867,869 to Barrett discloses a grate magnet apparatus including a frame having an opening adapted to have material pass therethrough. The apparatus includes a non-magnetic tube supported by the frame and extending across the opening, and an elongated magnetic member removably housed in the tube. Magnetic material is attracted to the tube when the magnetic member is housed in the tube. The magnetic material is released from the tube when the magnetic member is removed from the tube. The non-magnetic tubes and magnet members are connected both for joint movement to be withdrawn from the path of the flowing material and then for relative movement to release magnetic material from the non-magnetic tube. 
         [0005]    U.S. Pat. No. 5,066,390 to Rhodes et al. discloses a magnetic separator with a reciprocal grate. The magnetic separator includes a plurality of elongated magnetic members that are parallel with one another. A first end plate is connected to adjacent terminal ends of the magnetic members to hold the magnetic members with the longitudinal axes generally defining a common plane. Non-magnetic sheathing members are disposed sheathing the entire longitudinal length of the magnetic members. A second end plate is connected to adjacent terminal ends of the non-magnetic members to provide longitudinal sheathing and unsheathing movement of the sheathing members with respect to the magnetic members for cleaning accumulated magnetic particles from the exterior surface of the non-magnetic members. The first and second end plates are adapted for reciprocating movement in the common plane, preferably in a direction generally perpendicular to the longitudinal axes of the magnetic members to reduce bridging and clogging of the material flow. 
         [0006]    U.S. Pat. Nos. 5,188,239 to Stowe, 5,190,159 to Barker, 6,250,475 to Kwasniewicz et al., and 6,902,066 to Yang disclose other metallic particle separating machines that have magnetic tubes that are retracted for wiping or cleaning accumulated metallic particles from the tubes. 
         [0007]    In spite of the above advances, there remains a need for a metallic particle separating machine that may be cleaned in a more efficient and efficacious manner. There also remains a need for a magnetic particle separating machine that may be continuously operated, and that does not have to be shut down or stopped in order to clean the internal components of the machine. There also remains a need for a metallic particle separating machine that efficiently collects magnetic particles for disposal. 
         [0008]    These and other preferred embodiments of the present invention will be described in more detail below. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention generally relates to a separating machine that removes metallic and/or magnetic particles from materials, such as spices, chemicals, powders, dry bulk goods, and pharmaceutical ingredients. The separating machine desirably includes an upper end having an inlet and a lower end having an outlet. The machine includes a first flow path extending between the inlet and the outlet and a second flow path also extending between the inlet and the outlet. The first and second flow paths define separate and distinct paths or conduits that extend between the inlet and the outlet. The separating machine also includes a diverter valve having a flap extending therefrom at the inlet that directs the material through either the first flow path or the second flow path. In a first position, the flap of the diverter valve directs the material through the first flow path. In a second position, the flap of the diverter valve directs the material through the second flow path. The first flow path includes a first array of magnets that capture the metallic and/or magnetic particles present in the material when the material passes therethrough. The second flow path also includes an array of magnets that operate in a manner that is similar to the first array of magnets. 
         [0010]    In operation, the flap of the diverter valve adjacent the inlet may be placed in a first position so that the material is directed through the first flow path. As the material passes through the first flow path, the array of magnets remove the metallic particles present in the material. After a period of exposure to the flow of the material, the magnets become covered with the attracted metallic particles, thereby requiring the magnets to be cleaned. Preferably, the machine includes a retraction and wiping mechanism that enable the magnets to be wiped clean of the metallic particles. As the magnets are wiped clean, the magnetic particles fall into a trap located adjacent the lower end of the machine. As the magnetic array in the first flow path is being cleaned, the flap of the diverter valve is in the second position for directing the material through the second flow path. In the second position, the material is directed through the second flow path until the array of magnets are at least partially covered by the metallic particles. The second array of magnets may then be cleaned in a similar manner as discussed above with respect to the first array of magnets. 
         [0011]    The flap of the diverter valve is desirably moved back and forth between the at least two positions for alternating the flow direction of the material. Preferably, when one of the flow paths is being utilized for removing the metallic particles from the material, the magnets in the other flow path are being cleaned. The removing metallic particles and cleaning steps may be continuously alternated between the first and second flow paths. The frequency for alternating between the first and second switch positions is preferably dependent upon the concentration of metallic particles present in the material. 
         [0012]    Although the present invention is not limited by any particular theory of operation, it is believed that providing two or more distinct paths for removing metallic particles from the solid material will enable the machine to operate continuously. Conventional metallic particle separator machines must be shut down to clean the magnets, which prevents continuous operation and reduces the volume of material from which metallic and/or magnetic particles may be separated. 
         [0013]    In one preferred embodiment of the present invention, a metallic particle separating machine includes an inlet for receiving a material having metallic and/or magnetic particles mixed therein, and an outlet for discharging the material after the metallic particles have been separated therefrom. The separating machine desirably includes first and second flow paths extending between the inlet and the outlet, a first magnetic element positionable in the first flow path, and a second magnetic element positionable in the second flow path. The separating machine also preferably includes a control system having a first state for directing the material through the first flow path and a second state for directing the material through the second flow path. The first and second flow paths are preferably separate and distinct from one another so that the material is directed through only one of the flow paths at any point in time. 
         [0014]    The first and second magnetic elements are desirably adapted to magnetically attract the metallic particles present in the material as the material passes between the inlet and the outlet. In certain preferred embodiments, the first magnetic element includes a first array of magnetic bars extendable across the first flow path. The first array of magnetic bars is desirably retractable from the first flow path for cleaning the magnetic bars and/or removing the metallic particles from the magnetic bars. The second magnetic element may include a second array of magnetic bars extendable across the second flow path. The second array of magnetic bars is desirably retractable from the second flow path for cleaning the magnetic bars and removing the metallic particles from the second magnetic bars. In certain preferred embodiments, one or more of the magnetic bars may include a magnetic part and a non-magnetic part. 
         [0015]    The separating machine may also include one or more cleaning elements in communication with the first and second arrays of magnetic bars for removing metallic particles from the first and second arrays of magnetic bars. The cleaning element may comprise a wiper, such as a wiper plate or wiper washers, in contact with the first and/or second arrays of magnetic bars. The cleaning element may also include a pressurized fluid, such as compressed air, directed at the outer surfaces of the magnetic bars. 
         [0016]    Preferably, the separating machine of the present invention includes a plurality of pneumatic valves that serve to control movable elements in the machine. Generally, a pneumatic valve actuator may be used to adjust a valves position by converting air pressure into linear or rotary motion. For example, in the present invention a pneumatic valve is preferably used to rotate a top flap located adjacent the inlet from a first to a second position, the top flap used for directing material that enters the inlet into either the first or second flow paths. Further, a pneumatic valve may be used to control the movement of magnetic bars in a linear direction, namely out of and back into the first and second flow paths respectively. Further still, pneumatic valves may be used to rotate bottom flaps located adjacent the outlet from a first to a second position. 
         [0017]    The separating machine preferably further includes a timer associated with the pneumatic valves. The timer is generally used to set the actuation interval of the valves. After an interval is chosen, and the timer is set, the pneumatic valves will be actuated after each interval has ended. At such a time, the separating machine may change from a first state wherein material is directed through the first flow path to a second state wherein material is directed through the second flow path and vice versa depending upon which state the separating machine is in. 
         [0018]    Preferably, an operator sets the timer to a specific interval. The interval indicates the amount of time between actuations of each of the pneumatic valves that control the position of the top flap, the first and second array of magnetic bars, and the bottom left and bottom right flap. The interval is generally determined by the capacity of magnetic particles that the magnetic bars located in a flow path can contain at any one time. 
         [0019]    In some instances, the amount of metallic and/or magnetic particles in a certain material that will run through a flow path during a given time period may be calculated by an operator. If the amount of magnetic particles in a certain material is known or generally known, then the amount of magnetic particles that will be contained on a magnetic bar or array of magnetic bars in a flow path may be approximated for a certain amount of material directed through a flow path for a given time period. For example, the operator may calculate that the first array of magnetic bars may contain X amount of magnetic particles after Y amount of material enters the first flow path for Z amount of time. Therefore, an operator may set the timer of the separating machine to a specific interval such that the optimum amount of material may pass through the system while making sure that the magnetic bars are capable of performing their separating function. 
         [0020]    In one embodiment of the present invention, a material having a known amount of magnetized particles may be sent through the inlet and received by the first flow path when the top flap is in the first position. At this time, the first array of magnetic bars are in the first flow path collecting magnetized particles as material flows through the flow path. Also preferably at this time, the bottom left flap is in the first position wherein material passing through the first array of magnetic bars may continue along the first flow path and through to the outlet. 
         [0021]    The separating machine preferably includes a timer that may be set to actuate pneumatic valves in the system at set intervals. Preferably, at the end of an interval a pneumatic valve is actuated causing the top flap extending from the pneumatic valve to rotate from the first position to the second position. At this time, the pneumatic valves controlling the first array of magnetic bars and the bottom left flap for the first magnetic collection assembly may also be actuated. Preferably, the pneumatic valve controlling the first array of magnetic bars will cause the bars to retract from the first flow path in order to begin the cleaning process of the bars. Preferably, the pneumatic valve controlling the bottom left flap for the first magnetic collection assembly will cause the flap to rotate into the second position wherein the magnetic particles falling from the magnetic bars are directed to enter a metallic particle collection drawer. 
         [0022]    Also preferably at this time, the second array of magnetic bars are in a first position located in the second flow path wherein material entering the inlet is now being received by the second flow path. Also preferably at this time, the bottom right flap is in the first position wherein material passing through the second array of magnetic bars may continue along the second flow path and through to the outlet. 
         [0023]    When the current interval has ended, the five pneumatic valves controlling the top flap, the first and second array of magnetic bars, and the bottom left and right flap are all preferably actuated. At this time, the pneumatic valve controlling the top flap will preferably be actuated causing the top flap to rotate from the second position back to the first position. At this time, the pneumatic valves controlling the second array of magnetic bars and the bottom right flap for the second magnetic collection assembly may also be actuated. Preferably, the pneumatic valve controlling the second array of magnetic bars will cause the bars to retract from the second flow path in order to begin the cleaning process of the bars. Preferably, the pneumatic valve controlling the bottom right flap for the second magnetic collection assembly will cause the flap to rotate into the second position wherein the magnetic particles falling from the magnetic bars are directed to enter a metallic particle collection drawer. 
         [0024]    Also preferably at this time, the pneumatic valve controlling the first array of magnetic bars will cause the magnetic bars to advance back into a first position located in the first flow path wherein the magnetic bars may collect magnetized particles as material flows through the flow path. Also preferably at this time, the bottom left flap is in the first position wherein material passing through the first array of magnetic bars may continue along the first flow path and through to the outlet. 
         [0025]    When the current interval has ended, the above process may repeat itself continuously as long as the separating machine is running. 
         [0026]    In an alternative embodiment, the control system preferably includes a diverter valve that is movable to a first position for directing the material through the first flow path and a second position for directing the material through the second flow path. The control system desirably has a sensor for sensing a concentration of the metallic particles in the material. The control system also desirably includes a microprocessor in communication with the sensor and the diverter valve. The microprocessor may generate signals for moving the diverter valve between the first and second positions in response to the sensed concentration of the metallic particles present in the material. The microprocessor is preferably adapted to analyze the concentration of the metallic particles present in the material and to adjust the switching frequency of the diverter valve in response to the concentration of the metallic particles present in the material. 
         [0027]    In another preferred embodiment of the present invention, a metallic or magnetic particle separating machine includes an inlet for receiving a material having metallic particles mixed therein, an outlet for discharging the material after the metallic particles have been separated therefrom, and at least two flow paths extending between the inlet and the outlet. The separating machine desirably includes at least one magnetic element positionable in each of the flow paths for attracting the metallic particles present in the material, and a control system including a diverter valve for selectively directing the material through each of the flow paths. Each flow path is preferably separate and distinct from one another so that the material is directed through only one of the flow paths at any point in time. 
         [0028]    The control system desirably includes a diverter valve that is movable to at least a first position for directing the material through a first flow path and a second position for directing the material through a second flow path. The control system may include a sensor for sensing a concentration of the metallic particles in the material, and a microprocessor in communication with the sensor and the diverter valve, whereby the microprocessor is adapted to analyze the concentration of the metallic particles present in the material and to adjust the switching frequency of the diverter valve in response to the concentration of the metallic particles present in the material. 
         [0029]    In still another preferred embodiment of the present invention, a continuously operating metallic particle separating machine includes an inlet for receiving a material having metallic particles mixed therein, an outlet for discharging the material after the metallic particles have been separated therefrom, a first flow path extending between the inlet and the outlet, a first magnetic element positionable in the first flow path, a second flow path extending between the inlet and the outlet, a second magnetic element positionable in the second flow path, and a control system including a diverter valve switchable between a first position for directing the material through the first flow path and a second position for directing the material through the second flow path, whereby a switching frequency of the diverter valve is responsive to the concentration of metallic particles in the material. 
         [0030]    These and other preferred embodiments of the present invention will be described in more detail below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1A  shows a front cross-sectional view of a metallic particle separating machine including first and second flow paths and a diverter valve in a first position, in accordance with one preferred embodiment of the present invention. 
           [0032]      FIG. 1B  shows the metallic particle separating machine of  FIG. 1A  with the diverter valve in a second position. 
           [0033]      FIG. 2  shows a front cross-sectional view of an upper end of the metallic particle separating machine shown in  FIG. 1A . 
           [0034]      FIG. 3A  shows a fragmentary cross-sectional view of the metallic particle separating machine shown in  FIG. 1A , including an array of magnetic bars in a first position. 
           [0035]      FIG. 3B  shows a fragmentary cross-sectional view of the metallic particle separating machine shown in  FIG. 1A , with the array of magnetic bars in a second position. 
           [0036]      FIG. 4  shows a metallic particle separating machine, in accordance with another preferred embodiment of the present invention. 
           [0037]      FIG. 5  shows a cross-sectional side view of a metallic particle collection assembly used with the metallic particle separating machine described herein, in accordance with still another preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    Referring to  FIG. 1A , in certain preferred embodiments of the present invention, a metallic particle separating machine  100  includes an inlet  102 , an outlet  104 , a first flow path  106  that extends between the inlet  102  and the outlet  104 , and a second flow path  108  that also extends between inlet  102  and the outlet  104 . The first and second flow paths  106 ,  108  are separate and distinct from one another. The metallic particle separating machine  100  includes a first array of magnetic bars  110  provided in the first flow path  106 , and a first metallic particle collection assembly  112  movable between a substantially vertical position shown in  FIG. 1A  and a diagonal position ( FIG. 1B ). The operation of the first metallic particle collection assembly will be provided in more detail below. 
         [0039]    The metallic particle separating machine  100  also includes a second array of magnetic bars  114  disposed in the second flow path  108 , and a second metallic particle collection assembly  116  movable between the diagonal position shown in  FIG. 1A  and an upright position shown in  FIG. 1B . 
         [0040]    Referring to  FIGS. 1A and 1B , the metallic particle separating machine  100  includes a diverter valve  118  located adjacent the inlet  102  for directing material that enters the inlet through either the first flow path  106  or the second flow path  108 . Preferably, diverter valve  118  is a pneumatic valve. The diverter valve  118  includes a flap  119  that is movable from a first position ( FIG. 1A ) in which it directs material through the first flow path  106 , and a second position ( FIG. 1B ) in which it directs material through the second flow path  108 . The metallic particle separating machine includes a control system  120  for controlling operation of the diverter valve  118 , the first array of magnetic bars  110 , the second array of magnetic bars  114 , the first metallic particle collection assembly, and the second metallic particle collection assembly  116 . The control system  120  preferably includes a microprocessor and a program for operating all of the components discussed above. The control system  120  also preferably includes a sensor for detecting the concentration of metallic or magnetic particles present in a material passing through the metallic particle separating machine  100 . 
         [0041]    The flap  119  of the diverter valve  118  is movable to the second position shown in  FIG. 1B  for directing material through the second flow path  108 . When the flap  119  of the diverter valve  118  is in the second position, the first metallic particle collection assembly  112  is in the extended position, and the second metallic particle collection assembly  116  is in the retracted position. 
         [0042]    Preferably, separating machine  100  of the present invention includes a plurality of pneumatic valves  118 ,  150 ,  152 ,  154 ,  156  that serve to control movable elements in the machine. Generally, a pneumatic valve actuator may be used to adjust a valves position by converting air pressure into linear or rotary motion. For example, pneumatic valve  118  is preferably used to rotate a top flap  119  from a first to a second position, top flap  119  used for directing material that enters the inlet into either first or second flow paths  106 ,  108 . Further, pneumatic valves  150 ,  154  may be used to control the movement of magnetic bars in a linear direction, namely out of and back into the first and second flow paths respectively. Further still, pneumatic valves  152 ,  156  may be used to rotate bottom flaps  112 ,  116  from a first to a second position. 
         [0043]    Preferably, separating machine  100  further includes a timer (not shown) associated with pneumatic valves  118 ,  150 ,  152 ,  154 ,  156 . The timer is generally used to set the actuation interval of the valves. After an interval is chosen, and the timer is set, pneumatic valves  118 ,  150 ,  152 ,  154 ,  156  will be actuated after each interval has ended. At such a time, the separating machine may change from a first state wherein material is directed through first flow path  106  to a second state wherein material is directed through second flow path  108  and vice versa depending upon which state the separating machine is in. 
         [0044]    Preferably, an operator sets the timer to a specific interval. The interval indicates the amount of time between actuations of each of pneumatic valves  118 ,  150 ,  152 ,  154 ,  156  that control the position of top flap  119 , first and second array of magnetic bars  110 ,  114 , and left and right bottom flaps  112 ,  116 . The interval is generally determined by the capacity of magnetic particles that magnetic bars  110 ,  114  located in either flow path  106 ,  108  can contain at any one time. 
         [0045]    In some instances, the amount of metallic and/or magnetic particles in a certain material that will run through a flow path during a given time period may be calculated by an operator. If the amount of magnetic particles in a certain material is known or generally known, then the amount of magnetic particles that will be contained on a magnetic bar or array of magnetic bars in a flow path may be approximated for a certain amount of material directed through a flow path for a given time period. For example, the operator may calculate that the first array of magnetic bars may contain X amount of magnetic particles after Y amount of material enters the first flow path for Z amount of time. If the operator knows how much magnetic particles the array of magnetic bars can contain at any one time, the operator can then set the interval so that the array of magnetic bars change from a separating state to a cleaning state. 
         [0046]    In one embodiment of the present invention, a material  122  having a known amount of magnetized particles may be sent through inlet  102  and received by first flow path  106  when top flap  119  is in the first position. At this time, first array of magnetic bars  110  are in first flow path  106  collecting magnetized particles as material  122  flows through flow path  106 . Also preferably at this time, bottom left flap  112  is in the first position wherein material  122  passing through first array of magnetic bars  110  may continue along first flow path and  106  through to outlet  104 . 
         [0047]    The timer may be set to actuate pneumatic valve  118  controlling top flap  119  to rotate top flap  119  from the first position to the second position at the end of the interval. As pneumatic valve  118  controlling top flap  119  is actuated, top flap  119  will rotate from the first position to a second position. At this time, pneumatic valves  150 ,  152  controlling first array of magnetic bars  110  and bottom left flap  112  for first magnetic collection assembly may also be actuated. Preferably, pneumatic valve  150  controlling first array of magnetic bars  110  will cause the bars to retract from first flow path  106  in order to begin the cleaning process of the bars. Preferably, pneumatic valve  152  controlling bottom left flap  112  for first magnetic collection assembly will cause the flap to rotate into the second position wherein the magnetic particles falling from magnetic bars  110  are directed to enter a metallic particle collection drawer. 
         [0048]    Also preferably at this time, second array of magnetic bars  114  are in a first position located in second flow path  108  wherein material  122  entering inlet  102  is now being received by second flow path  108 . Also preferably at this time, bottom right flap  116  is in the first position wherein material  122  passing through second array of magnetic bars  114  may continue along second flow path  108  and through to outlet  104 . 
         [0049]    When the current interval has ended, the five pneumatic valves  118 ,  150 ,  152 ,  154 ,  156  controlling top flap  119 , first and second array of magnetic bars  110 ,  114 , and bottom left and right flaps  112 ,  116  respectively, are all preferably actuated. Preferably at this time, pneumatic valve  118  controlling top flap  119  will be actuated causing top flap  119  to rotate from the second position back to the first position. At this time, pneumatic valves  154 ,  156  controlling second array of magnetic bars  114  and bottom right flap  116  for second magnetic collection assembly may also be actuated. Preferably, pneumatic valve  154  controlling second array of magnetic bars  114  will cause the bars to retract from second flow path  108  in order to begin the cleaning process of the bars. Preferably, pneumatic valve  156  controlling bottom right flap  116  for the second magnetic collection assembly will cause the flap to rotate into the second position wherein the magnetic particles falling from the magnetic bars are directed to enter a metallic particle collection drawer  142 . 
         [0050]    Also preferably at this time, pneumatic valve  150  controlling first array of magnetic bars  110  will cause the magnetic bars to advance back into a first position located in first flow path  106  wherein the magnetic bars may collect magnetized particles as material  122  flows through the flow path. Also preferably at this time, bottom left flap  112  is in the first position wherein material  122  passing through first array of magnetic bars  110  may continue along first flow path  106  and through to outlet  104 . 
         [0051]    When the current interval has ended, the above process may repeat itself continuously as long as the separating machine is running. 
         [0052]      FIG. 2  shows the upper end of the metallic particle separating machine  100  shown in  FIGS. 1A and 1B . As shown in  FIG. 2 , the metallic particle separating machine  100  includes the inlet  102  that is adapted to receive a material, such as dry bulk material such as chemicals, spices, pharmaceutical ingredients, food ingredients, etc. Although the present invention is not limited by any particular theory of operation, it is believed that the metallic particle separating machine disclosed herein may be used for removing metallic particles from dry material goods such as spices. Typically, such dry material goods have metallic or magnetic particles mixed therein that must be removed before the dry material goods may be further processed to make spices, pharmaceutical products, chemicals or food products. 
         [0053]    Referring to  FIG. 2 , the actuator valve  118  includes a flap  119  that is movable between the first position  119 A and the second position  119 B. When the actuator valve  118  moves the flap to the first position designated by reference number  119 A, the material  122  is directed through the first flow path  106 . When the actuator valve  118  moves the flap to the second position designated by reference number  119 B, the material  122  is directed through the second flow path  108 . 
         [0054]      FIGS. 3A and 3B  show a fragmentary, cross-sectional view of the metallic particle separating machine  100  shown in  FIGS. 1A ,  1 B and  2 . In particular,  FIGS. 3A and 3B  show the second array of magnetic bars  114  that are provided in the second flow path  108  of the machine. Each of the magnetic bars  114  has a magnetic section  124  and a non-magnetic section  126 . In other preferred embodiments, the entire length of the bar  114  may be magnetic. In still other embodiments, the bars  114  may be activated into a magnetic state, and then deactivated so that the bars  114  are no longer magnetic. 
         [0055]    In preferred embodiments, the array of magnetic bars  114  are movable between the inserted or advanced position shown in  FIG. 3A  and the retracted position shown in  FIG. 3B . When the array of magnetic bars  114  are in the advanced position shown in  FIG. 3A , the magnetic portions  124  of the bars  114  are aligned with the second flow paths  108 . As the material  122  having the metallic particles mixed therein passes over the bars  114 , the magnetic portions  124  of the bars attract the metallic particles present in the material. As is well known to those skilled in the art, after a period of time, the outer surfaces of the magnetic portions  124  of the bars  114  will become covered by metallic particles. As a result, the bars must be cleaned of the metallic particles so that the bars can effectively remove the metallic particles present in the material. At this stage, the array of magnetic bars  114  are moved to the retracted position shown in  FIG. 3B  so that the non-magnetic portions  126  of the magnetic bars  114  are aligned with the second flow path  108 . 
         [0056]    Referring to  FIGS. 3A and 3B , the metallic particle separating machine  100  includes a wiping element  128 , such as wiping washers, which engage the outer surfaces of the bars  114 . The wiping element preferably scrapes the outer surfaces of the bars  114  as the bars are moved between the advanced position shown in  FIG. 3A  and the retracted position shown in  FIG. 3B . 
         [0057]    In certain preferred embodiments, the outer end of each of the bars  114  is attached to a plate  130  that provides for simultaneously movement of the bars  114  between the advanced position shown in  FIG. 3A  and the retracted position shown in  FIG. 3B . 
         [0058]    Referring to  FIG. 4 , in certain preferred embodiments of the present invention, the metallic particle separating machine  100  includes compressed air lines  132  that direct high pressure air at the outer surfaces of the magnetic bars  114 . In one preferred embodiment, the compressed air preferably provides a primary means for removing the metallic particles that have been collected on the outer surfaces of the bars  114 . In other preferred embodiments, the compressed air may provide a supplemental means for removing the metallic particles from the bars. In this embodiment, the wiping element  128  ( FIG. 3A ) provides the primary structure for removing the metallic particles from the bars  114  and the compressed air lines  132  ( FIG. 4 ) provide the supplemental means for removing the metallic particles from the bars  114 . Thus, the present invention may provide provides a wiping element and/or a high pressure air system that direct high pressure air at an outer surface of the bars for removing metallic particles from the magnetic bars. 
         [0059]      FIG. 5  shows an expanded view of the second metallic particle collection assembly  116  shown in  FIGS. 1A and 1B . The metallic particle collection assembly  116  includes a flap  140  movable between the extended position shown in  FIG. 5A  and an upright position (not shown). The flap  140 , when in the extended position, directs metallic particles into a metallic particle collection drawer  142 . The drawer  142  may be periodically emptied so that additional metallic particles may be collected in the metallic particle collection drawer  142 . 
         [0060]    Operation of the metallic particle separating machine discussed above will now be described in further detail. The metallic particle separating machine is designed to remove metallic particles that may be present in dry or solid materials such as spices, chemicals, pharmaceutical ingredients, and food ingredients such as flour, sugar, wheat and rye. The metallic particle separating machine of the  100  of the present invention is designed to efficiently remove the metallic particles present in the material as the material passes through the machine from the inlet  102  to the outlet  104 . The metallic particle separating machine is designed to operate continuously so that it does not need to be shut down in order to clean the magnetic bars disposed in the flow paths. 
         [0061]    As shown in  FIG. 1A , when the flap  119  of the diverter valve  118  is in the first position, the solid material  122  is directed through the first flow path  106  and onto the first array of magnetic bars  110 . As the material passes through the first array of magnetic bars  110 , the magnetic bars attract the metallic particles for removing the metallic particles that are present in the solid material  122 . When the flap  119  is in the first position, the metallic particle collection assembly  112  is in the upright position so that the filtered material may be discharged from the first flow path  106  and through the outlet  104 . As the material  122  is being directed through the first flow path  106 , the magnetic bars  114  in the second flow path  108  are being cleaned. The magnetic bars may be cleaned by retracting the bars to the position shown in  FIG. 3B  and/or by directing high-pressure fluid (e.g. compressed air) at the outer surfaces of the bars  114  to remove any metallic particles remaining on the outer surfaces of the bars  114 . The second metallic particle collection assembly  116  is in the extended position so that any metallic particles stripped or removed from the outer surfaces of the bars  114  may be directed into the metallic particle collection drawer  142  ( FIG. 5 ). 
         [0062]    The controller  120  ( FIGS. 1A and 1B ) preferably controls operation of the metallic particle separating machine  100  so that the machine may be operated continuously. The controller  120  desirably includes a sensor that detects or senses the concentration of metallic particles that are present in the material  122 . As is well known to those skilled in the art, the magnetic bars must be cleaned more frequently when there is a higher concentration of metallic particles present in the material. Thus, the switching of the flap  119  and the cleaning of the magnetic bars must occur more frequently when the concentration of metallic particles in the material is greater. This is because the magnetic bars quickly become fully covered with metallic particles and must be cleaned more frequently to effectively remove the metallic particles from the solid material. Thus, the sensor and the controller  120  continuously monitor the concentration of the metallic particles and switch the position of the flap  119  depending on the concentration of the metallic particle. The sensor may include an optical sensor that monitors the concentration and/or presence of metallic particles present on the outer surfaces of the magnetic bars. The sensor may also be located outside the separating machine. In other preferred embodiments, any sensor well-known to those skilled in the art for detecting the presence of metallic particles and the concentration of metallic particles in the solid material may be used. 
         [0063]    When the first array of magnetic bars are fully covered by metallic particles, the flap  119  is switched to the second flap position shown in  FIG. 1B . When the flap  119  is in the second flap position ( FIG. 1B ), the solid material  122  is directed through the second flow path  108  and onto the second array of magnetic bars  114 . The second array of magnetic bars  114  remove the metallic particles present in the material  122  so that the material discharged from the outlet  104  is free of metallic particles. As the solid material  122  is being directed through the second flow path  108 , the first array of magnets  110  in the first flow path  106  are being cleaned using the method described above. As the first array of magnets are being cleaned, the metallic particle discharge flap  112  is in the extended position for collecting the metallic particles that are removed from the first magnetic bars  110 . At the same time, the second metallic particle discharge flap  116  is in the upright or retracted position so that the solid material  122  (free of metallic particles) may be discharged through the outlet  104 . 
         [0064]    The controller  120  continuously monitors the concentration of the metallic particles present in the solid material  122 . When the concentration of metallic particles is greater, the diverter valve  118  must move between the first and second flap positions more frequently. This is because the magnetic bars  110 ,  114  more quickly become covered with the metallic particles. When the concentration of metallic particles is lower, the frequency for moving the flap  119  between the two flap positions is reduced. 
         [0065]    Although the present invention is not limited by any particular theory of operation, it is believed that providing at least two distinct and separate flow paths for removing metallic particles provides a metallic particle separating machine that may be operated continuously. This is because the material may be at all times directed through at least one flow path having an array of magnetic elements such as magnetic bars. As the array of magnetic bars in the first flow path are collecting the metallic particles, the array of magnetic bars in the second flow path may be cleaned. Once the array of magnetic bars in the second path are cleaned, the second flow path may be the primary path for removing the metallic particle, while the array of magnetic bars in the first flow path are being cleaned. The system preferably switches back and forth so that at all times an array of magnetic bars are available for removing metallic particles from the solid material. The present invention provides a dramatic improvement over prior art separating machines that must be periodically shut down for cleaning the magnets. Thus, the present invention provides an improved system for removing metallic particles from solid material, and the present invention provides a machine that may be operated continuously without requiring a shut-down period for cleaning the magnets. 
         [0066]    Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. For example, separating machines in other preferred embodiments of the present invention may have three of more flow paths used for separating metallic particles from material, with each flow path having its own magnetic element for removing metallic particles. The present invention may also be used for removing metallic particles from solids, liquids, or gasses, or any combination of solids, liquids, or gases. In still other preferred embodiments, the array of magnetic bars may include outer sheaths or tubes into which metallic bars are inserted. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.