Abstract:
The present invention provides a filtering apparatus generally comprising a reservoir containing a pool of dirty fluid, the reservoir defined at least in part by a pair of laterally spaced side walls. A drum is rotatably supported within the reservoir, the drum having a generally cylindrical body having a first end, a second end, and an opening therebetween to pass fluid. A filter element is connected to the drum body and covers the opening to filter fluid flowing into the drum. The drum body is journalled about its outer surface to the reservoir for rotation therein. As such, the drum does not require any end walls to support the drum, and the entire end of the drum is wide open to the flow of fluid, which increases the rate of flow through the filter, and permits the filter to be used with a wide range of fluid flows. Unique adjustment of the drum is also provided.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to apparatus for filtering dirty liquid such as machine tool coolant which contains metal chips and particles. More specifically, the invention relates to filtering apparatus of the same general type as disclosed in Lenhart U.S. Pat. No. 5,328,611.  
         BACKGROUND OF THE INVENTION  
         [0002]    In the apparatus disclosed in the Lenhart patent, a rotatable drum with a filtering screen is supported within a reservoir and is partially immersed in a pool of dirty liquid. Typically, the dirty liquid comprises machine tool coolant which is contaminated with metallic chips and particles. Coolant from that pool flows into the drum through the screen and is filtered by the screen. The clean coolant flows axially out of the drum through outlet openings in one end wall of the drum and an adjacent end wall of the reservoir. The drum includes end walls which generally comprise an outer ring connected by four spokes that meet at the center. An axle is journalled to this center portion of the end walls to support rotation of the drum.  
           [0003]    While these systems have enjoyed much commercial success, they have both upper and lower limits on the fluid flow they can process. Generally these systems are only sized for large machine centers which produce significant quantities of dirty coolant. To accommodate such high flows of fluid, the apparatuses must be rather large in size and structured to handle such large flows. Therefore, there exists a need for a smaller filtering apparatus for smaller machine tools. However, a smaller filtering apparatus is even further limited in the amount of dirty fluid it can process. Therefore, there exists a need not only to provide a filtering apparatus suitable for use with small machining tools, but also a filtering apparatus which can at the same time be adapted for a series of small machine tools or even some larger machine centers and capable of handling their larger flows of dirty coolant.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    In light of the above, it is a general aim of the present invention to provide a filtering apparatus suitable for use with small machine tools.  
           [0005]    In that regard it is also an object of the present invention to provide such a filtering apparatus which is also suitable for use with a series of small machine tools or larger machine centers.  
           [0006]    It is another object of the present invention to provide a filtering apparatus which increases the flow therethrough such that the filtering apparatus is suitable for filtering a wide range of small and large flows of dirty fluid from machine tools or centers.  
           [0007]    In accordance with these objects, one embodiment of the present invention provides a filtering apparatus generally comprising a reservoir containing a pool of dirty fluid, the reservoir defined at least in part by a pair of laterally spaced side walls. A drum is rotatably supported within the reservoir, the drum having a generally cylindrical body having a first end, a second end, and an opening therebetween to pass fluid. A filter element is connected to the drum body and covers the opening to filter fluid flowing into the drum. The drum body is journalled about its outer surface to the reservoir for rotation therein. As such, the drum does not require any end walls to support the drum, and the entire end of the drum is wide open to the flow of fluid, which increases the rate of flow through the filter, and permits the apparatus to filter a wide range of fluid flows.  
           [0008]    According to its more detailed aspects, this embodiment of the present invention may further comprising a pair of bearings, each bearing being connected to one side wall to rotatably support the drum body about its outer surface. Preferably, the pair of bearings are polymer bearings.  
           [0009]    Another embodiment of the present invention provides a filtering apparatus generally comprising a reservoir containing a pool of dirty fluid, the reservoir defined at least in part by a pair of laterally spaced side walls. A drum is rotatably supported within the reservoir, the drum having a generally cylindrical body having a first end, a second end, and an opening therebetween to pass fluid. A filter element is connected to the drum body and covers the opening to filter fluid flowing into the drum. The first and second ends of the drum body are adjustably supported by the side walls, the first and second ends being independently adjustable.  
           [0010]    According to its more detailed aspects, this embodiment of the present invention may further comprise a pair of flanges connected to the pair of side walls, the flanges supporting the ends of the drum body. Preferably, each flange includes a plurality of slotted apertures that receive bolts for attaching the flange to the side wall. Moreover, the plurality of slotted apertures are oriented to permit omni-directional adjustment of each end of the drum body. As in the above embodiment, the drum body is journalled about its outer surface to eliminate the need for end walls on the drum body.  
           [0011]    Yet another embodiment of the present invention provides a filtering apparatus generally comprising a reservoir containing a pool of dirty fluid, the reservoir defined at least in part by a pair of laterally spaced side walls. A drum is rotatably supported within the reservoir, the drum having a generally cylindrical body having a first end, a second end, and an opening therebetween to pass fluid. A filter element is connected to the drum body and covers the opening to filter fluid flowing into the drum. The apparatus also includes a pair of laterally spaced bearings, each bearing connected to one side wall to rotatably support the drum body about the outer surface. Finally, the apparatus further includes a pair of laterally spaced seals. The pair of seals are mounted to the outer surface of the drum body and engage the pair of side walls to provide a fluidic seal therebetween. Preferably, each seal is located laterally inside each bearing to seal the bearing from dirty fluid and to keep fine chips from returning to the clean coolant tank.  
           [0012]    According to its more detailed aspects, this embodiment of the present invention may further comprise a pair of laterally spaced flanges adjustably connected to the pair of side walls. Here, the bearings are connected to the flanges to support the ends of the drum body about the outer surface, while the seals engaging the flanges to provide a fluidic seal therebetween. Preferably, each flange is independently adjustable relative to the side wall to which it is connected.  
           [0013]    Other objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:  
         [0015]    [0015]FIG. 1 is a front view of an embodiment of the filtering apparatus constructed in accordance with the teachings of the present invention.  
         [0016]    [0016]FIG. 2 is a cross-sectional view of the filtering apparatus of FIG. 1 taken about line  2 - 2 . 
     
    
       [0017]    While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now to the drawings, FIGS. 1 and 2 show an embodiment of the present invention. This embodiment generally comprises a filtering apparatus  20  for filtering dirty fluid and for producing a flow of clean fluid. The fluid may, for example, be machine tool coolant which is contaminated with metallic chips and particles.  
         [0019]    The filtering apparatus  20  includes a dirty coolant reservoir  22  defined in part by a bottom wall  23  and a pair of laterally spaced side walls  24  and  25  and containing a pool  26  of dirty coolant (FIG. 2). Dirty coolant enters the reservoir  22  by way of an inlet which exists in the area indicated generally by numeral  27  in FIG. 2. A filter drum  30  is located at least partially between the side walls  24 ,  25  and is partially immersed in the pool  26  of dirty coolant. The drum  30  includes a generally cylindrical body  32  having a first end  33  and a second end  34 . Between the opposing ends  33 ,  34  of the drum body  32 , the drum includes a central portion  35  having at least one opening therein for passing fluid. Preferably, the central portion  35  of the drum body  32  includes a series of circumferentially spaced slots which are separated by thin reinforcing strips of drum body material. A flat filter belt is wrapped around the drum  30  to form a tubular filter element  36  that extends between the ends  33 ,  34  of the drum body  32 , proximate the openings  35 , to filter dirty coolant passing therethrough. Preferably, the filter element is a fine screen mesh belt. The filter element  36  is retained on the outer surface of the drum by laterally spaced clamps  38  which cooperates with a filter belt clamp plate  40  to securely position the filter element  36 .  
         [0020]    The drum  30  is adapted to be rotated within the reservoir  22 . In the present embodiment, the rotation is effected by a pair of laterally spaced chains  45  operably engaged with the outside of the drum via a sprocket  44  connected to the outer surface of the drum body  32 . A guide  44 ′ is also connected to the outer surface of the drum and is laterally spaced from the sprocket to guide the other laterally spaced chain  45 . At the other end of the chains  45  drive sprockets  50  are keyed to a drive shaft  48  operably connected to a motor  46  through a gear box or speed reducer  47 . The end of the drive shaft  48  opposite the motor  46  is supported by a bearing  52  which selectively mounts to the side wall  25  of the reservoir. It will be understood that the filtering apparatus of the present invention may be used as a left handed or a right handed machine. More specifically, the bearing within the motor  46  is utilized such that the entire motor  46 , gear box  47 , drive shaft  48 , sprocket  50  and bearing  52  may be flipped 180° to reverse the orientation of the machine.  
         [0021]    Heavy chips in the dirty coolant entering the inlet  27  settle to the bottom of the reservoir  23  and are carried upwardly by drag bars or scrapers  60  which span the chains  45  These heavy chips are carried along the bottom wall  23  of the reservoir  22  and are discharged through an outlet  37 . A hand cart (not shown) may be positioned below the outlet  37  and may be periodically dumped.  
         [0022]    Lighter chips and fine particles in the dirty pool  26  are filtered by the screen mesh  36  as the coolant passes upwardly through the filter element  36  and the openings in the drum body  32  and into the interior of the drum  30 . Clean coolant which is filtered by the screen mesh  36  flows axially out of one end of the drum and collects in a clean coolant tank (not shown). A pump may be associated with the tank to deliver clean coolant to machine tools or other devices which may utilize said coolant. Clean coolant is also pumped to spray nozzles  58  located inside of the drum  30  and directed towards the inner face of the filter element  36 . As the drum rotates, the clean coolant from the nozzles  58  continuously backwashes the filter element  36  flush filtered out particles therefrom. Such particles accumulate on the bottom wall  23  of the reservoir  22  and are carried away by the scrapers  60  in the form of sludge.  
         [0023]    According to the present invention, the filtering apparatus  20  is structured to accommodate the flow of dirty coolant from small machine tools, but also increases the flow handling capability of the filtering apparatus to increase its versatility. Notably, the drum  30  is journalled about its outer surface to the side walls  24 ,  25  of the reservoir  22 . Moreover, the invention includes provision for independently adjusting each end of the cylinder barrel relative to the reservoir to ensure smooth actuation and well as close tolerancing of the scrapers  60  with the bottom wall  23  of the reservoir  22  to ensure efficient removal metallic chips and particles. By journalled the drum  30  about its outer surface, the drum need only comprise a generally cylindrical body  32 , and need not include any end walls at the ends  33 ,  34  of the body  32  for engaging a hub or axle about those end walls, i.e. within the interior of the drum  30 . Accordingly, the end of the drum is free of restriction and hence increases the flow out of an axial end of the drum  30 . Furthermore, the point at which fluid is exiting the drum  30  has been lowered by removing any such end walls or spokes, also increasing the flow of clean coolant exiting the drum  30 .  
         [0024]    As shown in the figures, two laterally spaced generally circular flanges  70 ,  71  are connected to the side walls  24 ,  25 , respectively. Each flange  70 ,  71  is generally L-shaped in cross-section to provide an inner peripheral surface having a bearing  80 ,  82  for journalling the outer surface of the drum body  32 . Preferably, the bearings  80 ,  82  are polymer bearings, and in the preferred embodiment have been selected as turcite, although it will be recognized in the art that any other suitable bearings such as other low-friction material bearings, roller bearings, slipper bearings, etc., can also be used in conjunction with the present invention. Two laterally spaced seals  42 ,  43  are also provided to serve as a boundary between the pool of dirty coolant  26  and the clean coolant exiting axially from the drum  30 . The seals  42 ,  43  are V-type seals as is well known in the art. Preferably, each seal ring  42 ,  43  is attached to the outer surface of the drum adjacent to, and laterally outward of the laterally spaced chain guide  44 ′ and sprocket  44  driving the drum  30 . As such, the seals  42 ,  43  rotate with the drum  30  and the entire seal can be easily inspected for excessive wear. In the illustrated embodiment the seals  42 ,  43  seal to the adjustable flanges  70 ,  71  which are connected to and extend from the side walls  24 ,  25 . While the seals in the past have abutted the side walls, the seal are intended to seal to the flanges which are easier to manufacture uniformly than the side wall, thereby providing a stronger and more reliable seal.  
         [0025]    Each end  33 ,  34  of the drum is adjustable by virtue of their connection to the side walls  24 ,  25  via the intermediary of flanges  70 ,  71 . As best seen in FIG. 2, each flange  70 ,  71  includes a plurality of slotted apertures  72  spaced around the periphery of the flange. Studs are used to connect the flanges  70 ,  71  to the side walls  24 ,  25  via the slotted apertures  72 . The axis of each slotted aperture  72  is oriented relative to the other axes of the other aperture  72  to permit the flanges  70 ,  71  to be easily adjusted. A pipe bracket  54  is also attached to the flange  70  and supports a spray pipe  56  which feeds clean coolant to the nozzles  58  for cleaning the filter element  36 . A central stud  55  not only connects the bracket  54  to the flange  70 , but also extends through the side wall  24 . A stud (not shown) links the other flange  71  to the side wall  25  in a similar manner. As such, the stud acts as a pivot point about which the drum  30  rotates to adjust its relative position within the apparatus  20 , making adjustment easy since the barrel  30  need not be lifted.  
         [0026]    It will be recognized that by virtue of mounting the spray pipe  56  and nozzles  58  to the circular flange  70 , as well as the bearings  80 ,  82  to the flanges  70 ,  71 , each end  33 ,  34  of the drum  30  may be independently adjusted in relation to the side walls  24 ,  25 , yet the filter element  36  will be properly cleaned and the drum  30  will be properly supported rotationally regardless of the independent adjustments of each end  33 ,  34  of the drum  30 . It will also be recognized by locating the seals  42 ,  43  laterally inside the bearings  80 ,  82 , the bearings are separated from dirty coolant. Thus the metal chips and particles will not interrupt their function. Similarly, the bearings  80 ,  82  will be lubricated only by clean fluid exiting axially out of the drum adjacent the bearings. Furthermore, the seals  42 ,  43  will always be properly positioned to reliably seal against the flanges  70 ,  71 , regardless of the independent adjustment of each drum end  33 ,  34 . By virtue of each end  33 ,  34  of the drum  30  being independently adjustable, proper orientation of the drum  30  relative to the drive shaft  48  and sprockets  50 , as well as the chains  45  is ensured. Additionally, the relative position of the scraper  60  to the bottom wall  23  of the reservoir  22  can be accurately controlled to ensure a efficient and smooth removal of particles from the bottom of the reservoir  22  upwards to the outlet  37 .  
         [0027]    All of the references cited herein, including patents, patent applications, and publications, are hereby incorporated in their entireties by reference.  
         [0028]    The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.