Abstract:
The invention is a detachable “blade foil” system for comminuting machines which employ a rotating turbine. The turbine blades are each endowed with a detachable leading edge which is shaped in an air foil configuration. These “blade foils” are penetrated by a vent chamber having an inlet port and an outlet port. The vent chambers aid in drying input material that is processed by a comminuting machine and also aid in reducing sound from the turbine. The configuration of the inventive blade foils also vary to aid in material drying. The configuration of the blade foils also define the level of particle size attributed to the processed output material. Hence by selecting particular blade foil configurations the operator can achieve different levels of material drying and differing output particle sizings.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of U.S. provisional patent application Ser. No. 61/019,369, filed on Jan. 7, 2008. 
    
    
     TECHNICAL FIELD 
     This invention relates to comminuting devices for reducing the particle size of materials, and more particularly to comminuting devices which employ a rotating turbine mounted in a housing for causing an air flow through an expansion chamber. 
     BACKGROUND 
     Comminuting devices which use a high speed rotating turbine to reduce the size of and to separate particulate materials have been in existence for quite some time. Devices of this type are found in the patents attributed to Rolle, et al. (U.S. Pat. Nos. 4,852,818; 4,718,609; and 4,892,261). The turbine component of the device is made of a plurality of air foil blades mounted on a backing plate and is dimensioned in close tolerances to a housing. Mounted in front of the turbine blade and its housing is an expansion chamber of frusto-conical shape. 
     In these devices, material to be comminuted is carried in an air stream through an acceleration tube and into the expansion chamber, where it is rapidly decompressed, causing it to explode. The spinning turbine produces a negative pressure in the expansion chamber and introducing raw materials at a specific rate into the chamber allows air trapped in the material to expand in the negative pressure environment, thereby causing the explosion of the material into smaller particles. The smaller particles can then be size-separated by methods well known in the art, such as by a specific gravity separator. 
     It is known in the art of comminuting devices that adjusting the negative pressure achieved by the device results in variations in particle size dimensions. Known methods for varying the negative pressure include varying the RPM of the turbine and varying the length of the expansion chamber. However, the art has not addressed varying the design of the turbine blades or the leading edges of the turbine blades to help achieve further fine tuning of the negative pressure variants achievable in comminuting devices. 
     The foregoing reflects the state of the art of which the inventor is aware, and is tendered with a view toward discharging the inventor&#39;s acknowledged duty of candor, which may be pertinent to the patentability of the present invention. It is respectfully stipulated, however, that the foregoing discussion does not teach or render obvious, singly or when considered in combination, the inventor&#39;s claimed invention. 
     SUMMARY OF THE INVENTION 
     The invention is an improved turbine design for a comminuting device; the improvements include variations to the leading edge portion of the turbine blade. In the instant invention, the leading edges are removably attached to the turbine blades and comprise air foils. For purposes of this description, the leading edges will be termed “blade foils” herein. The blade foils have a vent chamber penetrating there through, each vent chamber having an inlet port and an outlet port where the inlet is typically narrower than the outlet port. The blade foils increase the volume of air through which the comminuted material must pass, thus resulting in faster and more complete drying of the material than found in prior art comminuting machines. The shape of the blade foils vary in that differing foil configurations result in differing sizing of material particles at discharge, and also differing moisture contents present in the discharged material. Further adjustments to the angle of the blade foils, the size of the vent chamber, the shape of the vent chamber and the blade angles all contribute to differing performance in terms of air flow volume and moisture reduction in the material that is discharged from the comminuting device incorporating the noted improvements. 
     Accordingly, the following objects and advantages of the invention apply: 
     It is an object of this invention to provide a comminuting machine which allows for multiple turbine parameters to be set up to specifically achieve selected particle sizes of materials and selected moisture content of materials. 
     It is another object of this invention to provide a system of leading edge air foils (blade foils) which can be attached to a comminuting machine turbine to produce a higher or lower volume of air movement, selectable particle sizes in discharged materials and increased or decreased moisture reduction in discharged materials. 
     Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiments of the invention, without placing limitations thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a turbine for a comminuting machine shown without blade foils attached. 
         FIG. 2  is a perspective view of the turbine of  FIG. 1 , this view showing the blade foils attached to the turbine. 
         FIG. 3A  is a side view of a turbine blade with attached blade foil, this variant of the blade foil being of a tightened configuration. 
         FIG. 3B  is a side view of a turbine blade with attached blade foil, this variant of the blade foil being of a medium configuration. 
         FIG. 3C  is a side view of a turbine blade with attached blade foil, this variant of the blade foil being of a relaxed configuration. 
         FIG. 4  is a perspective view of a blade foil detached from the turbine blade of the invention. 
         FIG. 5  is a perspective view of the inventive turbine blade mounted in a comminuting machine, which is drawn in phantom. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring generally to  FIGS. 1 and 2 , a turbine  10  for a comminuting machine in accordance with the invention is shown. This turbine  10  is comprised of a backing plate  12 , where here, six turbine blades  14  are attached to the backing plate and extend upward from the backing plate. The blades  14  can be attached to the backing plate  12  by any suitable means, such as bolting or welding to the backing plate. The blades are joined together at a central axis  11 . As shown in  FIG. 2 , attached to the leading edges  16  of the turbine blades  14  are corresponding detachable blade foils  18 . Leading edges  16  are angled to give the blade foils the proper attitude when contacting an air flow. The blade foils  18  function to provide increased volumes of air movement through the machine and also to provide varying degrees of moisture content present in the discharged particulate materials. While blade foils  18  can be permanently attached to blades  14 , the true utility of the invention is realized when the blade foils  18  are detachably joined to blades  14 . The blade foils  18  can be attached to the leading edge  16  of the turbine blades  14  by bolting at through-holes  20 , which are imparted in the leading edges  16 , as shown here. Blade foils  18  have corresponding through-holes  21  which align with through holes  20  of turbine blades. Through-holes  21  in blade foils  18  can be threaded for introducing a correspondingly threaded hex head bolt fastener  19 . Through-holes  20  can be chamfered for flushly receiving hex head bolt  19 . It is preferable that the blade foils  18  be easily replaceable, to affect desired results at discharge or to affect easy change-out at the end of their useful life. To insure maximum life span and decrease static buildup, the blade foils  18  are constructed from carbide and metal combinations; the blades  14  preferably have a ceramic or tungsten coating for increasing longevity. 
     Referring also to  FIGS. 3A ,  3 B and  3 C are examples of three varying configurations of blade foils  18 . Blade foils have a concave section  25  on their front surface  31  which faces into the air as the turbine blade spins. The shape of the concave section  25  affects the amount of vacuum flow (negative pressure) occurring within the expansion chamber of a comminuting machine employing the inventive turbine.  FIG. 3A  illustrates a tightened blade foil configuration where the concave section  25  is more elongated than the other examples shown in  FIGS. 3B and 3C .  FIG. 3B , represents a medium blade foil configuration where the concave section  25  is more radically curved than that of  FIG. 3A , but less so than the configuration of  FIG. 3C , which represents a relaxed configuration. The concave section  25  of the  FIG. 3A  example of blade foil  18  ends in a leading edge  34  which is approximately parallel to backing plate  12 . In the  FIG. 3B  example, the leading edge  34  points in a slightly downward and off-parallel relation to backing plate  12 . In  FIG. 3C , the leading edge  34  points toward and perpendicularly to the backing plate  12 . 
     The different foil configurations allow a comminuting machine to be configured for specific materials and allow particle size and moisture content of the processed material to be altered to desired parameters. The tightened configuration of  FIG. 3A  results in producing the maximum vacuum flow (negative pressure), of the three configurations shown, and causes the input material to endure maximum fracturing and therefore the highest discrimination in resulting output particle sizes. The relaxed configuration of  FIG. 3C  results in the least amount of vacuum flow (negative pressure) and lessened instances of fracturing, but the highest drying of output material (best moisture control). The medium configuration of  FIG. 3B  represents a compromise between the high level of material discrimination of the  FIG. 3A  variant, and the high level of moisture reduction of the  FIG. 3C  variant. Depending on the input material and the desired output, the operator can select between the blade foils  18  described to achieve the desired results. 
     Referring also to  FIG. 4 , the back surface  28  of blade foil  18  is preferably curved for good aerodynamic characteristics. Also, blade foils  18  have an overlapping cutout  30  for overlapping the leading edge  16  of turbine blades  14 . Upon mating cutout  30  upon leading edge  16 , the fit between blade foil  18  and turbine blade  14  is flush at the joining surfaces  32 ,  36  between leading edge  16  and blade foil  18 . 
     Still referring to the drawings, a vent chamber  22  penetrates each blade foil  18 . The vent chamber  22  has an inlet  26  and an outlet  24 , the inlet and outlet being circular or oval in shape. As shown here, the inlet  26  is larger in diameter than the outlet  24  which has effects on air volume and gives vent chamber  22  a conical shape. The vent chamber  22  is centered on the blade foil  18  and is positioned so that the inlet  26  opens out to the concave section  25  and provides venting of air captured within concave section  25  during rotation of the turbine  10 . The vent chamber  22  functions to increase air volume flowing between the adjacent turbine blades  14  to aid in drying particulate materials. Furthermore, the vent chamber  22  functions to increase air turbulence within the air stream to reduce sound transfer. Rotary turbine comminuting machines are known to create high decibel readings, which is a drawback to their operation in areas with adjacent populations. The sound reduction achieved by the inventive blade foils  18  is variable with the RPM of the turbine  10 , but sound reduction of 20% (percent) to 40% (percent) have been achieved when compared to standard comminuting systems. Note that alternatively arranging the vent chamber  22  so that the outlet is smaller than the inlet, air pressure is affected, as the vent chamber functions as a venturi in this configuration. Reversing the sizings of the inlet (large) and outlet (small) increases the material volume and reduces the amount of sound being transmitted from a comminuting machine. 
       FIG. 5  shows the inventive turbine as it would appear added to a comminuting machine. The turbine  10  is mounted in a housing  36  next to the expansion chamber  38 ; it is within the expansion chamber that the inlet material is fractured due to negative air pressure therein. When added to a turbine  10 , the inventive blade foils  18  have been found to reduce the moisture level in processed materials by a minimum of 16% (percent). The level of drying achieved by a machine employing the inventive blade foils  18 , has achieved several impressive results so far. One result has been the efficient processing of Kaolinite, which can be separated into valuable mud and silica sand components. Presently, the state of the art is to process Kaolinite using a wet process method which is energy and labor intensive. A comminuting machine employing the inventive blade foils  18  can bring processing costs down to as low as 10% of the cost per ton when compared to a wet process method. Kaolinite typically enters a machine employing the invention with 12.5% moisture content (by weight) and leaves the machine as a dry, processed dust. 
     Another efficient application of the invention is to apply it to ultra-fine coal particulate waste which is a by-product of coal processing. The invention can reduce the particulate to a coal dust, which can be directly used as a clean burning and highly efficient fuel for heating or power generation. 
     Other applications can be envisioned by the inventors for any particulate material which would benefit from the drying effects provided by the invention. For example, mine tailings, which typically have moisture contents of 15% (percent) or greater, cannot be processed presently, using only an air processing medium, until a significant amount of moisture has been removed by sunlight or expensive mechanical drying means. In contrast, the invention can bring the tailings within an acceptable moisture level for efficient processing. 
     Another application which is envisioned by the inventors is applying the invention to multiple machines connected in series. This will increase the tonnage passing through the invention without additional handling and/or transport costs associated with the processing of the material. Enhanced size and moisture control at discharge are also achieved. 
     Finally, although the description above contains much specificity, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. This invention may be altered and rearranged in numerous ways by one skilled in the art without departing from the coverage of any appended patent claims which are supported by this specification.