Abstract:
An extruder filter replacement and backwash structure includes an extruder body having a feed hole and a material outlet respectively located in opposing front and rear sides thereof, a first piston set with a first piston rod, and a second piston set with a second piston rod. Subject to cross connection between the first piston rod and second piston rod and the feed hole and material outlet of the extruder body, the first filter or second filter can be replaced without shutting down the extruder press, or backwashed during operation of the extruder press.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to extruder technology and more particularly, to an extruder filter replacement and backwash structure, which facilitates quick replacement of filters and is capable of backwashing filters. 
         [0003]    2. Description of the Related Art 
         [0004]    An extruder has filters installed therein for filtering the applied material. After a period of time in application, the filters can be contaminated with impurities to hinder the delivery of the applied material. Therefore, the filters of an extruder must be regularly replaced. However, when replacing the filters, the extruder must be shut down, resulting in machine capacity loss. 
       SUMMARY OF THE INVENTION 
       [0005]    It is the main object of the present invention to provide an extruder filter replacement and backwash structure, which facilitates replacement of filters without shutting down the extruder, avoiding machine capacity loss. 
         [0006]    It is the main object of the present invention to provide an extruder filter replacement and backwash structure, which is capable of backwashing the filters, prolonging the lifespan of the filters. 
         [0007]    To achieve these and other objects of the present invention, an extruder filter replacement and backwash structure used in an extruder press in accordance with the present invention comprises an extruder body, a first piston set and a second piston set. The extruder body comprises a first piston hole and a second piston hole disposed in a parallel relationship, and a feed hole and a material outlet respectively located in opposing front and rear sides thereof. The first piston set comprises a first piston rod mounted in the first piston hole, and a first filter and a first grille mounted in the first piston rod. The second piston set comprises a second piston rod mounted in the second piston hole, and a second filter and a second grille mounted in the second piston rod. Subject to cross connection between the first piston rod and second piston rod and the feed hole and material outlet, the first filter or second filter can be replaced without shutting down the extruder press, or backwashed during operation of the extruder press. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an oblique elevational view of an extruder press configured in accordance with the present invention. 
           [0009]      FIG. 2  is an oblique elevational view of the extruder body, first piston set and second piston set of the extruder filter replacement and backwash structure in accordance with the present invention. 
           [0010]      FIG. 3  is an exploded view of the extruder body, first piston set and second piston set of the extruder filter replacement and backwash structure in accordance with the present invention (I). 
           [0011]      FIG. 4  is an exploded view of the extruder body, first piston set and second piston set of the extruder filter replacement and backwash structure in accordance with the present invention (II). 
           [0012]      FIG. 5  is a sectional view of the extruder body of the extruder filter replacement and backwash structure in accordance with the present invention (I). 
           [0013]      FIG. 6  is a sectional view of the extruder body of the extruder filter replacement and backwash structure in accordance with the present invention (II). 
           [0014]      FIG. 7  is a schematic sectional view of the present invention, illustrating a status of the extruder filter replacement and backwash structure during the material filtering operation (I). 
           [0015]      FIG. 8  is a schematic sectional view of the present invention, illustrating a status of the extruder filter replacement and backwash structure during the material filtering operation (II). 
           [0016]      FIG. 9  is a schematic sectional view of the present invention, illustrating a status of the extruder filter replacement and backwash structure during a filter replacement operation. 
           [0017]      FIG. 10  is a schematic sectional view of the present invention, illustrating a status of the extruder filter replacement and backwash structure during a material discharge operation (I). 
           [0018]      FIG. 11  is a schematic sectional view of the present invention, illustrating a status of the extruder filter replacement and backwash structure during a material discharge operation (II). 
           [0019]      FIG. 12  is a schematic sectional view of a part of the present invention, illustrating a status of the first piston set during a backwashing operation therethrough. 
           [0020]      FIG. 13  is a schematic sectional view of a part of the present invention, illustrating a status of the second piston set during a backwashing operation through the first piston set. 
           [0021]      FIG. 14  is a schematic sectional view of a part of the present invention, illustrating a status of the first piston set during a backwashing operation through the second piston set. 
           [0022]      FIG. 15  is a schematic sectional view of a part of the present invention, illustrating a status of the second piston set during a backwashing operation therethrough. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring to  FIGS. 1-9 , an extruder filter replacement and backwash structure in accordance with the present invention is shown. The extruder filter replacement and backwash structure in accordance with comprises an extruder body  1 , a first piston set  2  and a second piston set  3 . The extruder body  1  is mounted on the machine base  6 . 
         [0024]    The extruder body  1  comprises a first piston hole  11  and a second piston hole  12  arranged therein in a parallel relationship. Further, the first piston hole  11  and the second piston hole  12  extend through opposing left and right sides of the extruder body  1 . The extruder body  1  further comprises a feed hole  13  and a material outlet  14  respectively located in opposing front and back surfaces thereof, a connection block  17  located around the feed hole  13  for the connection of a feeder (not shown), a first feed passage  131  and a second feed passage  132  defined in the feed hole  13  and respectively disposed in communication with the first piston hole  11  and the second piston hole  12 , a first material outlet passage  141  and a first backwash passage  142  defined in the material outlet  14  and respectively disposed in communication with the first piston hole  11 , a second material outlet passage  143  and a second backwash passage  144  defined in the material outlet  14  and respectively disposed in communication with the second piston hole  12 , a first material expelling hole  15  disposed adjacent to the feed hole  13  and in communication with the first piston hole  11 , and a second material expelling hole  16  disposed adjacent to the feed hole  13  and in communication with the second piston hole  12 . 
         [0025]    The first piston set  2  comprises a first piston rod  21 , a first filter  22  and a first grille  23 . The first piston rod  21  comprises a first filter hole  211  located in the periphery thereof at one side, and a first material passage  212  and a first backwash hole  213  located in the periphery thereof at an opposite side and respectively connected to the first filter hole  211 . The first piston rod  21  is movably mounted in the first piston hole  11  of the extruder body  1  to keep the first filter hole  211  near the feed hole  13  of the extruder body  1 . The first material passage  212  and the first backwash hole  213  are disposed adjacent to the material outlet  14  of the extruder body  1 . Further, first locating rods  214  are symmetrically disposed in the first filter hole  211  at two opposite lateral sides. The first filter  22  and the first grille  23  are mounted in the first filter hole  211 . The first grille  23  comprises a plurality of first locating holes  231  located in two opposite lateral sides thereof and respectively fastened to the first locating rods  214 . 
         [0026]    The second piston set  3  comprises a second piston rod  31 , a second filter  32  and a second grille  33 . The second piston rod  31  comprises a second filter hole  311  located in the periphery thereof at one side, and a second material passage  312  and a second backwash hole  313  located in the periphery thereof at an opposite side and respectively connected to the second filter hole  311 . The second piston rod  31  is movably mounted in the second piston hole  12  of the extruder body  1  to keep the second filter hole  311  near the feed hole  13  of the extruder body  1 . The second material passage  312  and the second backwash hole  313  are disposed adjacent to the material outlet  14  of the extruder body  1 . Further, second locating rods  314  are symmetrically disposed in the second filter hole  311  at two opposite lateral sides. The second filter  32  and the second grille  33  are mounted in the second filter hole  311 . The second grille  33  comprises a plurality of second locating holes  331  located in two opposite lateral sides thereof and respectively fastened to the second locating rods  314 . 
         [0027]    Further, a discharge mechanism  4  is connected to the extruder body  1  near the material outlet  14 . The discharge mechanism  4  comprises a material expelling passage  41  connected to the material outlet  14 , and a relief valve  42  controllable to close/open the material expelling passage  41 . The relief valve  42  comprises a communication passage  421  and a relief passage  422 . Further, a hydraulic press  5  is disposed at one lateral side relative to the extruder body  1 . The hydraulic press  5  comprises first hydraulic cylinder  51  connected to the first piston rod  21  of the first piston set  2 , and a second hydraulic cylinder  52  connected to the second piston rod  31  of the second piston set  3 . Thus, the first piston rod  21  and the second piston rod  31  are controllable by the hydraulic press  5  to reciprocate in the first piston hole  11  and the second piston hole  12  respectively. Further, the hydraulic press  5  is connected with the relief valve  42  of the discharge mechanism  4  for moving the relief valve  42  between the open position and the close position. 
         [0028]    Referring to  FIGS. 1 ,  7  and  8  again, during a normal material filtering operation of the first piston set  2  and the second piston set  3 , the hydraulic press  5  drives the relief valve  42  of the discharge mechanism  4  to the position where the communication passage  421  of the relief valve  42  is kept in communication with the material expelling passage  41 , and therefore the material expelling passage  41  is opened. At the same time, the hydraulic press  5  controls the first piston rod  21  of the first piston set  2  and the second piston rod  31  of the second piston set  3  to let the first filter hole  211  of the first piston rod  21  be connected to the first feed passage  131  in the feed hole  13 , the first material passage  212  and the first backwash hole  213  be respectively disposed in communication with the first material outlet passage  141  and first backwash passage  142  of the material outlet  14 , the second filter hole  311  of the second piston rod  31  be connected to the second feed passage  132  of the feed hole  13 , and the second material passage  312  and the second backwash hole  313  be respectively connected to the second material outlet passage  143  and the second backwash passage  144  in the material outlet  14 . At this time, the first material expelling hole  15  of the extruder body  1  is blocked by the first piston rod  21  and the second material expelling hole  16  is blocked by the second piston rod  31 . Thus, when the applied material is fed into the feed hole  13  of the extruder body  1 , the applied material will flow through the first feed passage  131  and the second feed passage  132  into the first filter hole  211  and the second filter hole  311  and will then be filtered by the first filter  22  and the second filter  32  and then guided out of the material outlet  14  and then expelled out of the material expelling passage  41  of the discharge mechanism  4 . 
         [0029]    Referring to  FIGS. 1 ,  3 ,  8  and  9  again, when changing the second filter  32  of the second piston set  3 , the hydraulic press  5  is controlled to move the second piston rod  31  out of the extruder body  1 , enabling the operator to replace the second filter  32  of the second piston rod  31 . At this time, the first piston set  2  keeps filtering the applied material. Similarly, when changing the first filter  22  of the first piston set  2 , the hydraulic press  5  is controlled to move the first piston rod  21  out of the extruder body  1 , enabling the operator to replace the first filter  22  of the first piston rod  21 . At this time, the second piston set  3  keeps filtering the applied material. 
         [0030]    Referring to  FIGS. 10 and 11  and  FIG. 1  again, if the extruder press gives off an overpressure warning signal, or if the operator is unable to relieves the pressure immediately when replacing the first filter  22 /second filter  32  and backwashing the first filter  22 /second filter  32 , the hydraulic press  5  will control the relief valve  42  at this time, moving the relief valve  42  to the position where the relief passage  422  is in communication with the material outlet  14  for discharging the applied material out of the discharge mechanism  4  through the relief passage  422  without passing through the material expelling passage  41 , avoiding any manufacturing process trouble due to machine shutdown. 
         [0031]    Referring to  FIGS. 12-15  and  FIG. 1  again, when the first piston set  2  is changed from the filtering mode to the backwash mode, the second piston set  3  is maintained in the filtering mode, enabling the hydraulic press  5  to move the relief valve  42  of the discharge mechanism  4  to the position where the material expelling passage  41  of the relief valve  42  is blocked to close the material outlet  14 , and also to move the first piston rod  21  to the position where the first filter hole  211  and first material passage  212  of the first piston rod  21  are respectively kept in communication with the first material expelling hole  15  and the first backwash passage  142 . Because the material outlet  14  is blocked at this time, the material filtered through the second piston set  3  will be guided through the first backwash passage  142  to the first piston rod  21  and then and then expelled out of the first material expelling hole  15 . Thus, the material flows reversely through the first piston rod  21  to backwash the first filter  22 . Similarly, as shown in  FIGS. 14 and 15 , when the second piston set  3  is changed from the filtering mode to the backwash mode, the first piston set  2  is maintained in the filtering mode, enabling the hydraulic press  5  to move the relief valve  42  of the discharge mechanism  4  to the position where the material expelling passage  41  of the relief valve  42  is blocked to close the material outlet  14 , and also to move the second piston rod  31  to the position where the second filter hole  311  and second material passage  312  of the second piston rod  31  are respectively kept in communication with the second material expelling hole  16  and the second backwash passage  144 . Because the material outlet  14  is blocked at this time, the material filtered through the first piston set  2  will be guided through the second backwash passage  144  to the second piston rod  31  and then and then expelled out of the second material expelling hole  16 . Thus, the material flows reversely through the second piston rod  31  to backwash the second filter  32 .