Patent Publication Number: US-6336559-B1

Title: Spiral separator with replaceable trough sections

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of spiral separators; and more particularly, to such separators with replaceable trough inserts or sections. 
     2. Description of the Related Art 
     The prior art to this invention includes spiral separators employed to separate mixtures of particulate materials into their component parts. Minerals of different densities are frequently separated by passing a liquid slurry of the mineral mixture through such a separator and allowing the more dense mineral to move by centrifugal forces created in the spiral flow of the slurry to an outflow where a splitter makes a final separation between two types of materials. When spirals are provided with spaced textured surfaces to improve spiral performance, these surfaces wear more than the remainder of the spiral due to friction which decreases the performance and eventually require replacement of the entire spiral. This is quite costly and there is a need for a better solution to extend the useful life of the spiral. 
     Among the many prior art patents are: U.S. Pat. No. 5,184,731 to Robertson et al, which describes and claims a spiral trough separator having protuberances in the trough to agitate ore particles and provide an increased separation of particles; and U.S. Pat. No. 5,452,805 to Robertson et al, which describes and claims a spiral separator having spaced groups of parallel grooves leading to spaced drains in the trough to provide an improved separation of particles in the feed. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention provides for alteration of the separation characteristics of a spiral separator by providing a separator that has replaceable inserts or sections of the trough; the replacement inserts including different types, sizes, or distributions of flow deflectors that are capable of altering the flow directions of different materials as they are pushed along by the gravitational liquid flow. Preferably, the replacement sections are small enough and made with sufficient precision that the section can be pressed into place without the assistance of fasteners, etc. but they may be used, if desired. The flow deflectors that may be used on such replacement sections includes all the known types of small obstructions to smooth flow, including, but not limited to, abrasive studded surface, grooves, protuberance of any shape, hillocks, riffles, ridges, steps, valleys, etc. The shape of the replacement section is not critical although rectangular or angular shapes are preferred since there would be no tendency to rotate and while a circular shape is preferred when it is desired to have the capability of adjusting the direction of flow in the trough of the separator. Any replacement section may be permanently fastened to the trough of the separator once it has been adjusted to its most productive flow direction. However, the principal advantages of this invention are to readily change the separation characteristics of the separator in a way that is not permanent and is ready for another quick change and when the obstructions wear, thereby decreasing efficiency, i.e., the sections may be replaced at a tremendous savings to the users on an order of magnitude ten to twenty over replacement of the entire spiral thereby extending the useful life of the spiral. The properties of the spiral can be adjusted and optimized by turning the circular insert, e.g., in the event the feed material is changed. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The novel features believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which: 
     FIG. 1 is a front elevational view of a spiral conveyor separator in accord with the present invention; 
     FIG. 2 is a perspective view of one flight or turn in the conveyor-separator of FIG. 1 wherein the trough of the conveyor-separator has been modified by introducing a plurality of protuberances in the path of the liquid and particles flowing down the spiral; 
     FIG. 3 is a perspective view of the same portion of the conveyor-separator as shown in FIG. 2, but altered in its flow characteristics by replacing the portion of the trough shown in FIG. 2 with a different section having a different set of flow deflectors; namely, four parallel, wide grooves. 
     FIG. 4 is a perspective view similar to that of FIG. 3, except that the replacement section of the trough is a smaller section and it introduces three parallel, upstanding ridges as flow deflectors; 
     FIG. 5 is a perspective view similar to that of FIG.  4  and showing abrasive studded surface areas as flow deflectors; and 
     FIG. 6 is a cross-section through a replacement section of any acceptable type that is fastened to the trough by a bolt and a wingnut. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A typical spiral conveyor is shown in FIG. 1 including an axial support column  10  and support arms  11  both of which may be built of any material so long as they support the spiral trough  12  which is endless between the entranceway  13  and the exitway  14 . Generally, the support column  10  may be of metal, such as aluminum or stainless steel. The spiral trough  12  is of fiberglass, or other materials if the situation demands it. In the case of a separator, which is the principal use to which this invention is directed, there is also an adjustable splitter  14 A located at the exitway  14  to permanently divide the two products that have been separated from each other as they have traveled down the trough  12  of the spiral conveyor. The purpose of the spiral is to feed a mixture of particulate minerals into the trough at entranceway  13  and to recover from exitway  14  particles of one type near the outside circumference of the trough  12 . It is not necessary that the two types of particles be separated as far apart as the complete width of the trough  12 , it is only necessary that the separation be such that a knife edge of the splitter  14 A can be appropriately positioned to divide particles of one type from particles of the other type. Splitters can also be positioned at locations along the trough  12  to remove separated material, as known in the art. 
     In FIG. 2 there is shown a replacement section  16  having small bumps or protuberances  17  arranged in whatever pattern the owner chooses that is known to assist in affecting the separation of particles as they flow down the trough  15  of the separator. The section  16  is shaped like the inside of trough  15  and is fastened in place in any way suitable; preferably in a noninvasive way so that the trough  12  is not weakened or the smooth flow of liquid is not disrupted by any seams (ridges or grooves) between the insert or section  16  and the depression  24  formed in the trough  15 . Also, section  16  should be secure in its seat in the depression  24  so that it will not easily be dislodged. 
     FIG. 4 illustrates another alternative design of flow deflector that may be used with the spiral separator of this invention. In this case the individual deflector is a raised bead or rib of material located so as to lie with its lengthwise dimension across the flow line of the liquid slurry of particles. Again design and testing determines the most productive position for the deflectors and, if time permits, the size and shape of the most productive deflector for the flowing mixture of particles that are to be separated. 
     FIG. 5 depicts a plurality of spaced abrasive or grit studded surface areas  20  on the surface of replacement section  16  of the spiral and act to deflect the flow of the solid particles in the slurry and/or impede the flow of solid particles and/or enhancing the separation thereof. 
     FIG. 6 shows an arrangement of fastening that is easy to manipulate and can be accomplished quickly by having a depression  24  conforming in size to section  16  in the trough  12  into which the replacement section  16  is tightly inserted or snapped. Section  16  may be provided with a reduced lip or flange  27  extending about its border which correspondingly fits within a groove or fold  28  in the side wall  29  defining depression  24 . The flange  27  need not be continuous but may be formed by a plurality of spaced tabs or the like with a plurality of corresponding slots defining groove  28 . FIG. 5 illustrates another fastening arrangement for replacement section  16  to trough  15  by a simple bolt  22  that has its head welded or embedded in the section  16  or fastened to replacement section  16 , passed through a hole  25  in the depression  24  of trough  15  and a washer seal  26  placed on the bolt  22  outwardly of trough  15  and a wing nut  23  tightened to maintain section  25  in place and the hole sealed against leakage. The particular attachment, with or without  27  and  28 , shown in FIG. 6 is especially adapted when the insert or section  16  is round and small to be substantially planar so that section  16  may be angularly adjusted to provide different flow characteristics. 
     While the invention has been described with respect to certain specific embodiments, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. It is intended, therefore, by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.