Abstract:
A grain separator having an easily replaceable seal. The separator comprises a housing and a rotatable grain separation drum carried by the housing, the drum having an end face with an external annular bearing surface. A drive shaft extends axially into the drum through the end face, and a grain inlet is carried exteriorly of the housing and includes a bearing rotationally supporting an end of the drive shaft. The inlet includes an inlet spout that extends through the end face for conveying grain to the drum. An easily removable and replaceable split seal is carried about the inlet spout and engages the annular bearing surface to seal the drum from the exterior of the inlet spout, and pressure means are provided for applying axial pressure to the split seal to urge the seal against the annular bearing surface. Disclosed also is a method for seal replacement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to U.S. Application Ser. No. 60/493,385, filed on Aug. 6, 2003, entitled “Improved Split Inlet Seal For Grain Separators”, which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention relates to easily replaceable split seals for use in grain separators. 
   BACKGROUND OF THE INVENTION 
   Grain separators are employed to separate a stream of grain containing various types and sizes of grain into constituent parts. Typical grain separators are used to separate such grains as wheat, durum, oats, barley and rice. 
   A grain separator is described in Hauch, U.S. Pat. No. 5,335,792. The grain separator includes a drum that rotates about a horizontal axis. Grain of varying sizes or types is added through an inlet at one end of the drum. Small indentations formed on the cylindrical wall of the drum capture the individual grain particles, and as the drum rotates, these particles are lifted until the fall from the indentations into an interior trough. The trough may be so oriented as to capture grain particles of a given size range. Grain is moved from the inlet into the drum by means of a rotatable heliacal screw which typically is driven by an electric motor through linkage including a drive shaft. The end of the drum nearest the grain inlet is provided with an end face, and the grain inlet includes a spout that extends through the end face to convey grain to the drum. The drive shaft may be mounted through appropriate bearings at the grain inlet. To provide a suitable seal between the grain inlet, which is stationary, and the drum, which rotates, an annular seal commonly is provided between the inlet and the drum. 
   Annular seals of the type described are highly susceptible to failure if grain or other debris finds its way between the bearing surface of the seal and the end plate surface of the drum against which the seal slides, and it is necessary, when this seal fails, to replace the seal. In the past, this has required disassembly of the grain inlet from the housing structure that supports the drum, or removal of the drum itself, and either of these approaches may be time consuming and difficult to accomplish, leading to undesired loss of production. 
   SUMMARY OF THE INVENTION 
   In one embodiment, the invention involves a grain separator having an easily replaceable seal, the separator comprising a housing and a rotatable grain separation drum carried by the housing, the drum having an end face with an external annular bearing surface. A drive shaft extends axially into the drum through the end face, and a grain inlet is carried exteriorly of the housing and includes a bearing rotationally supporting an end of the drive shaft. The grain inlet includes an inlet spout extending through the end face for conveying grain to the drum. A split seal is carried about the inlets spout, and is engagable with the annular bearing surface to seal the drum from the exterior of the inlet spout. Pressure means for applying actual pressure to the split seal is provided to urge the seal against the annular bearing surface. 
   In another embodiment, the invention relates to a method of replacing an annular seal between the inlet spout and the drum of a grain separator. The method comprises withdrawing axially movable seal-supporting structure axially away from the drum from a first position along the spout to provide manual access to the seal. The seal is disassembled into two or more segments and removed. A replacement seal is installed about the spout by joining replacement seal segments together. The seal supporting structure is then axially restored to its first position. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a perspective, broken away view of a grain separator and particularly the grain inlet; 
       FIG. 2  is a broken away, exploded top view of the grain separator of  FIG. 1 ; 
       FIG. 3  is a perspective view of a split seal and support ring; 
       FIG. 4  is a view of another split seal and support ring embodiment; 
       FIG. 5  is a cross sectional view of a spring-loaded plunger; and 
       FIG. 6  is an exploded, broken away top view of an embodiment of the invention employing the plunger shown in  FIG. 5 . 
   

   DETAILED DESCRIPTION 
   In the embodiment of  FIGS. 1 and 2 , a grain separator is shown generally as  10 , the separator having a housing  12 . A grain inlet is shown generally as  14  and comprises an upwardly open container into which grain may be poured, the grain inlet including a spout  16 . A drum  18  ( FIG. 2 ) is supported in the housing for rotation about its axis  18 . 1  by means of a drive belt  18 . 2 . A drive shaft  20  extends through the grain inlet  14  and is supported at its end by a bearing block  20 . 1 . The drive shaft extends into the drum, and is supported at its other end beyond the far end of the drum (not shown). Drive shaft  20  is provided with a helical screw portion  22  within the grain inlet  14  for the purpose of driving grain through the spout  16  and into the drum  18 . Another helical thread portion (not shown) is driven by the drive shaft within the drum, and this may occur in the manner shown in co-owned U.S. Pat. No. 5,335,792, the contents of which are incorporated herein by reference. 
   Referring to  FIG. 1 , the grain inlet  14  includes a standoff structure  14 . 1  that is attached to an inlet mounting subplate  34  and spaces the grain inlet opening  14 . 2  a predetermined distance away from the end  18 . 3  of the drum, thus exposing a predetermined length of the spout  16  to render it manually accessible, as will be described further below. 
   With reference to  FIG. 2 , which shows the mechanism at the grain inlet end of the grain separator in an exploded view, the drum  18  is shown as having an end face  18 . 4  that provides an annular bearing surface surrounding the opening into the drum. An annular seal  24  is positioned about the spout  16  and has a bearing surface  24 . 1  that confronts and engages the annular bearing surface  18 . 4  of the drum. The split seal  24  is supported by a support ring  26 , of which more will be said in connection with  FIG. 3 . An annular wave spring  28  of known design is positioned about the spout  16 , followed by an optional shim  30 , which may itself be split to enable it to be assembled with and disassembled from the split ring supporting structure. Each shim may take the form of a plate of given thickness, the plate having one edge provided with a generally semicircular opening such that when the shims are mounted on either side of the spout, the semicircular openings face each other and provide an opening accommodating the spout. 
   A cover shown at  32  is provided, the cover being shown also in  FIG. 1 . The cover, shim, wave spring, support ring and split seal all are movable axially along the spout. 
   Referring again to  FIG. 3 , the split seal  24  may be made of any appropriate sealing material that is adapted to seal against the annular bearing face of the drum. The seal may be made, for example, from an acetal resin such as Delrin® (DuPont), from polyethylene (particularly ultra high molecular weight polyethylene), poly(tetrafluouroethylene), felt, or other material.  FIG. 3  shows the seal as it may be made of Delrin®, the seal being provided in two segments, although three or more segments could be used if desired. The split seal may have tabs, shown at  24 . 2  that extend away from the bearing surface  24 . 1  of the seal, the tabs extending through similarly shaped slots  26 . 1  formed through the thickness of the support ring  26 . The ends of the seal segments have smaller tabs  24 . 3  sized so that when the seal segment ends are juxtaposed, the confronting tabs  24 . 3  are both received within appropriately shaped slot  26 . 2  formed through the thickness of the support ring. 
   In this embodiment, then, although the split seal  24  itself may be separated into two or more segments, the support ring  30  is not segmented, and, during replacement of seals, remains about the spout  16 . It will be understood that the support ring  30  itself may be segmented as desired. 
   Referring to  FIG. 1 , the further structure and method of this embodiment may be described in connection with a method of replacing a split seal that has worn out or has become torn or otherwise damaged. 
   Cover  32  is mounted to an inlet mounting subplate  34 , which is part of the housing l 2 , by a series of bolts  32 . 1 , which also serve to mount optional shims. The embodiment of  FIG. 1  may use four mounting bolts  32 . 1  that are spaced about the circumference of the spout, the upper two of which are shown in FIG. labove the spout  16  and the other two of which are beneath the spout to engage a substantially identical portion of the cover  32  that projects beneath the spout. The mounting bolts  32 . 1  pass through respective slotted holes  32 . 2  formed in the cover, the slots desirably having a key hole configuration with the larger end of each slot permitting passage through it of the head of a mounting bolt. In this manner, once the mounting bolts are loosened, the cover can be rotated slightly about its axis (clockwise in  FIG. 1 ) to line up the bolt heads with the larger ends of the respective key hole slots to enable the cover to be withdrawn axially away from the subplate  34 , as shown in  FIG. 2 . Any shims  30  that had been used can be removed at this time as well, the split nature of the shims permitting them to be removed outward from the spout  16 . 
   Wave spring  28  is then moved axially along the spout away from the drum, as shown in  FIG. 2 , to expose the split seal  24  and the split seal support ring  26 . The split seal can be removed from the support ring manually by withdrawing the tabs  24 . 2 ,  24 . 3  from the respective slots in the support ring, and the split seal segments can then be removed easily and discarded. A replacement split seal is then provided, its tabs  24 . 2 ,  24 . 3  inserted through the respective slots in the support ring, and the split seal is moved axially to bring its bearing surface  24 . 1  into contact with the bearing surface  18 . 4  of the drum. The wave spring  28  is then moved into contact with the support ring  26 , and it may be noted here that the diameter of the wave spring desirably is less than the diameter spacing the tabs  24 . 2  of the split ring (see  FIG. 3 ) so that the confronting face of the wave spring abuts the surface of the support ring  26 . The cover  32  is then moved forward against the wave spring to compress it, the bolt heads are received within the key hole slots  32 . 2  of the cover, and the cover is rotated slightly to lock the bolt heads against the smaller diameter portion of the key hole slots. If less pressure is desired on the split ring, the shims  30  shown in  FIG. 2  may be inserted from the top and bottom between the cover  32  and the inlet mounting subplate  34 , the shims having slots within which the bolts  32 . 1  are received. The bolts are then tightened and the machine is ready for use. 
   As shown is  FIGS. 1 and 2 , the spout  16  has a surface that is provided with an axially extending groove  16 . 1 , and the split ring  24  is provided with a radially inwardly projecting finger  24 . 4  that is slightably received in the groove  16 . 1  the finger and groove cooperating to prevent rotation of the seal with respect to the grained inlet. The finger  24 . 4 , of course, could be provided on the support ring  26 . 
   Although the cover and shim plates have been described as being held to the subplate  34  by bolts positioned above and below the spout, the bolts can be placed where desired about the spout, and additional threaded holes  34 . 1  may be provided to receive the threaded bolts. 
   A modified embodiment of a grain separator is shown in  FIGS. 4 through 6 . This embodiment is similar to that of  FIGS. 1–3 , and in certain respects, identical numbers have been used to identify similar features. 
   An inlet mounting subplate  40  is mounted to the frame  12  and has an opening in it that is large enough to accommodate a split seal, shown at  50 . The split seal is shown best in  FIG. 4  as consisting of two semicircular segments  50 . 1 . The seal portion itself may be made of any appropriate sealing material as described above in connection with the embodiment of  FIGS. 1–3 . For purposes of illustration, the seal in  FIG. 4  may be made of felt. The support ring, also split in this embodiment, is shown at  52 . The support ring segments have outwardly turned ends  52 . 1 , the ends having a small bore  52 . 2  formed through them. It will be understood that  FIG. 4 , which shows both front and side views, illustrates only half of a split seal, the other half being identical. The seal material may be glued or otherwise affixed to the support ring, and the inwardly turned ends of the support rings segments may be fastened together using small bolts and nuts, for example, or by any other means. 
   Returning to  FIG. 6 , the grain inlet  14  is similar to that shown in  FIG. 2 , and similarly has standoff bars  14 . 1  that are mounted to the inlet subplate  40 , as shown, to space the grain inlet opening  14 . 2  away from the end  18 . 3  of the drum. This, in turn, provides a distance along the spout that can be accessed manually to enable the split seal to be replaced easily. 
   The grain inlet includes a mounting plate  54  from which the stand off bars  14 . 1  extend. A plurality of spring loaded plungers  56  (shown also in  FIG. 5 ) each have a body that is threaded through a bore in the plate  54 . With reference to  FIG. 5 , each of the plungers  56  includes a body portion  56 . 1  having an exteriorly threaded portion  56 . 2  for threaded reception in the bores of the mounting plate  54 . The interior of the body  56 . 1  is hollow, and includes at one end an internally threaded portion receiving a threaded rod  56 . 3 , the rod terminating outwardly in a hexagonal cap  56 . 4 . At its other end, each plunger has an axially movable driver  56 . 5  having a portion that extends outward through an opening  56 . 6  in the end of the body and terminates in an outer bearing surface  56 . 7 . The driver  56 . 5  and the opening  56 . 6  at the end of the body have confronting shoulders preventing the driver from completely escaping from the end of the body. Between the threaded rod  56 . 3  and the driver  56 . 5  is positioned a helical compression spring  56 . 8  that seats against the confronting surfaces of the driver and the threaded rod and which urges the driver outward of the body. Spring force can be adjusted by advancing the threaded rod inward or outward of the body. The body  56 . 1  itself may have a hexagonal cross section, as shown in  FIG. 6 , to enable it to be forcefully threaded into the mounting plate bores using an appropriate wrench. 
     FIG. 6  illustrates a cover  58  that may be bolted as shown to the inlet mounting sub plate  40  to protect the split seal from contact with spilled grain or the like as it is poured into the inlet  14 . 2 . The plungers  56  extend through openings in the cover and into contact with the exterior face of the support ring  52  to force the split seal against the annular bearing surface  18 . 4  of the drum. As the seal wears, as through repeated use, the spring pressure holding the split seal against the drum can be adjusted by advancing the threaded portion  56 . 3  of the plungers into the body  56 . 1 . 
   To replace the split seal, the plungers  56  are backed out of the holes in the mounting plate  54 , thereby removing spring pressure from the split seal. The cover  58  is unbolted and is moved axially on the spout  16  away from the drum to expose the split seal and its support ring. The support ring carrying the split seal is disassembled and removed, and a replacement support ring with split seal is then assembled about the spout. The split ring is advanced into contact with the annular bearing surface of the drum, the cover  58  is remounted, and the plungers are again mounted to the support plate  54  with the spring loaded projections extending axially inwardly into contact with the support ring. By adjusting the axial position of the threaded rod within each plunger body, the desired degree of spring pressure against the split seal can be varied as desired. 
   While preferred embodiments of the present invention have been described, it should be understood that various changes, adaptations and modifications may be made therein, without departing from the spirit of the invention and the scope of the appended claims.