Abstract:
A conical element for filerting various substance and separating particles wherein a wire is wound in the form of a helix to form a helical slit between the adjoining peripheral margins of the wire thereby producing a linear treatment opening and increasing the area for filtering or separation to the utmost to improve the filtering or separation efficiency.

Description:
This is a continuation of copending U.S. application Ser. No. 07/184,080 filed on 4/20/88 abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a conical element for filtering various substances and separating particles. 
     2. Description of the Prior Art 
     Conventional, well-known conical elements of this type generally assume a structure provided with net-like or lattice-like filtering means. 
     There is also known a porous, conical element using ceramics for a coffee dripping apparatus. 
     The former structures provide filtering holes separated by solid areas, which results in relatively small filtering areas as compared to the total areas of filtering means, and leads to significant clogging. The smaller the particle size to be filtered, the greater the clogging problem. 
     On the other hand, with a porous structure impermeable foreign matter grows as a clog in the porous structure, resulting in unavoidable reduced filtering quantity. Accordingly, the foreign matter in the porous structure should be frequently removed completely. 
     SUMMARY OF THE INVENTION 
     The present invention is performed in view of the above problems. It is an object of the present invention to provide a conical element for filtering various substances and separating particles, wherein a wire is conically wound in the form of a helix to form a helical slit between the adjoining peripheral margins of the wire, thereby increasing the area for filtering or separation treatment as so-called linear treatment holes to the utmost to improve the filtering or separation efficiency. 
     Because of the conically shaped construction, which produces a sort of a funnel effect, the treating area for a liquid to be treated, such as a liquid or a gas, is increased. In addition, because the opening for filtering or separation is a helical slit, a so-called linear treatment hole is formed to improve the filtering. 
     The treating operation can smoothly be conducted because any residue, such as filtered waste, can be removed by simple operations such as back-wash or scraping. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view showing one embodiment of the conical element for filtering and separation according to the present invention; 
     FIG. 2 is an enlarged fragmentary sectional elevational view of an outer peripheral protion of the above; 
     FIG. 3 is an enlarged fragmentary sectional elevation of an upper annular portion thereof. 
     FIG. 4 is a cross-sectional view taken along the line IV--IV in FIG. 3; and 
     FIG. 5 is a fragmentary sectional plan view of a lower central portion thereof. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     One embodiment of the present invention is described below with reference to the drawings. 
     A conical frame plate 1 of which the surface is generally conical is composed of a central member 2, an annular member 3 provided on the outer periphery of the flat frame 1, and a plural number of support frames 4 provided between both members 2 and 3. Helical discrete locking grooves 5 are cut precisely and at a definite pitch from the center of the flat frame plate 1 toward the outer periphery thereof. A wire 6 is helically wound within the locking grooves 5 while being engaged therewith. The ends of the wire 6 are in engagement with concave grooves 7 formed in the annular member 3 and the central member 2, respectively, and are secured in the grooves using a locking device 8 such as a machine screw. 
     The wire 6 has a cross-section of an equilateral triangle and the engaging grooves 5 are shaped in the form of a V in agreement with the form of the surface of the wire 6. The adjoining inwardly facing surface of the wound wire 6 forms a smooth conical curved surface P. 
     A helical slit or hole 9 of uniform interval is provided between the adjoining peripheral margins of the wire 6 which is helically wound. The precision of the slit holes is determined by the processing precision of the wire 6, the cutting precision of the engaging grooves 5 into the conical frame plate 1, and by the winding operation of the wire 6. 
     With the wire 6 having a cross-section of an equilateral triangle, as illustrated by the embodiment shown in the drawing, and precision forming, the slit can be of a size below 1 micron in width. 
     The wire 6 and the conical frame plate 1 may be formed not only of metals but also of other preferred materials such as plastics or ceramics. 
     The smooth curved surface P of the helically wound wire 6 is directed to the primary side as illustrated in FIGS. 1 and 2, and in use the annular member 3 is fixed to a supply pipe on the outer periphery such that a desired fluid to be treated (a liquid or a gas) is allowed to pass toward the slit 9 in the direction of the arrow marks, i.e., from within the conical filter toward the exterior. 
     The residues, which are larger than the width of the slit 9 are removed from the fluid, particles smaller than the width of the slit 9 pass through. A filtering and separation of smaller from larger particles can also be accomplished, as well as a separation of solids from a fluid. 
     The residues which are filtered out and separated are piled up on the smooth curved surface P of the wire 6 but can easily be removed by reverse flushing. That is, by forcing fluid in the reverse direction from the exterior of the conical filter by means of back-washing. A scraper also can be used such that successive filtering and separation, and removal of residues, can be performed as is desired. 
     Although one embodiment of the present invention is described, it should be noted that the above conical frame plate 1 may comprise a flat plate on which a number of holes are provided, a lattice net plate, and a drainboard, all of which are processed in the form of a funnel, not shown, instead of the support frames 4, and the locking grooves 5 can be formed as grooves adapted to receive wire 6 having circular, or eliptical, or trapezoidal cross sections instead of the triangular form shown. 
     The wire 6 may be secured to frame plate 1 by means of a machine screw, or spot fusion, or an adhesive, in addition to fixation of both ends by means of the locking member 8, or instead of both end fixation. 
     According to the present invention, slit holes can be formed on the conical frame plate by means of the wire forming a smooth curved surface thereby markedly increasing the volume of treatment such as filtering and separation by so-called linear treatment holes. The slit holes themselves can be formed by the gap between the wire which is helically wound, such that the width can be determined precisely for enabling highly precise filtering and separation operations. 
     Because the filtering element is formed with an entirely smooth curved surface, it can be used with wide exchangeability as a permanent filtering and separation element for dripping coffee instead of various disposable filters.