Abstract:
An apparatus for recovering and cleaning contaminated abrasive blast media. A transportation assembly supplies contaminated blast media to an in feed cylinder within a rotating drum separator. The drum separator is formed from a plurality of elongated spaced parallel-aligned elements that define gradation openings between adjacent elements. The blast media is transported within the drum along the gradation interior surface. An internal spiral vein on the inside of the drum surface moves the media progressively through the drums exposing it to different areas of the drum surface having different gradation configurations. An air wash separator receives filtered blast media from the drum for final separation processing and reuse.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to devices for processing contaminated blast media for reuse. Such contaminants are comprised of dust, paint, rust which are entrained within the spent blast medium after use. 
     2. Description of Prior Art 
     Prior art devices of this type have used a variety of separation methods and apparatus, see for example U.S. Pat. Nos. 4,394,256, 4,771,579, 5,035,089, 5,195,640, 5,185,968, 5,269,424 and 5,695,37. 
     In U.S. Pat. No. 4,394,256 a separation apparatus is illustrated having a re-circulation chamber in which spent abrasives are recirculated at high velocity using the chamber&#39;s integral angled configuration to achieve primary separation. 
     U.S. Pat. No. 4,771,579 is directed to a cleaning and recovery device for abrasive blast media utilizing an internal air suspension in which media and contaminants of at least equal in weight drops out of the air suspension into a rotary filtered drum having a plurality of punch apertures within its surface to separate media and contaminants. 
     U.S. Pat. No. 5,035,089 claims a blast media recovery cleaning system having multiple separators. A fluidized bed is formed by use of a porous stone within a plenum. Compressed air is supplied to the stone so as to separate lower density materials from the higher density retaining the heavier materials within the plenum. 
     Applicant&#39;s own U.S. Pat. No. 5,185,968 is directed to a mobile separation system for abrasive blasting material using a multi-step separation and cleaning process in which a magnetic drum separator is used to process the contaminated blast media along with an integral air wash system. 
     U.S. Pat. No. 5,195,640 defines an abrasive blast media cleaning device using a rotating drum separator that uses high velocity air stream there through into which the contaminated blast material is repeatedly scooped up and dropped within. 
     Applicant&#39;s U.S. Pat. No. 5,269,424 claims a mobile apparatus for separation and recovery of spent abrasive blasting material utilizing magnetic drum separator in combination with an air wash dust collection and secondary wash for processing the blast media. 
     Finally, U.S. Pat. No. 3,695,385 discloses a recyclable abrasive blasting system and method utilizing multiple separation elements including a triple screening system. 
     SUMMARY OF THE INVENTION 
     A mobile apparatus for separation and recovery of abrasive blast material from entrained contaminants after use. A unique drum separator is used in combination with point intake and multiple outlet paths, one of which utilizes an air washer for final contaminant separation. The drum separator utilizes annular filtering slots of different sizes formed by independent spaced parallel annular angular inclined bands held together by radially spaced support rods. Abrasive blasts material is transported through the recovering drum separator by an integral continuous transportation vein affixed to its interior surface. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of the mobile separator; 
     FIG. 2 is a graphic representation in cross section illustrating material in feed for the separation drum of the invention and associated air wash; 
     FIG. 3 is a partial sectional view of the filtering drum of the invention illustrating central in feed of contaminated material and multiple outlet of filtered material there from; 
     FIG. 4 is an enlarged partial cross-sectional view of the filter drum of the invention; 
     FIG. 5 is an enlarged partial cross-sectional view of the filter drum&#39;s construction; 
     FIG. 6 is a graphic illustration of the multiple support elements of the filter drum; and 
     FIG. 7 is a graphic side elevational view of the filter drum of the invention and associated cleaning brushes and inlet and outflow of blast material there from. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1-4 of the drawings, an abrasive blast medium separator and recovery device  10  of the invention can be seen having an integral transportation base  11  with a support frame  12  extending there from. A bucket elevator  13  is positioned within the support frame  12  having an endless belt  14  with multiple material transportation buckets  15  extending there from as seen in 
     FIG. 2 of the drawings. The bucket elevator  13  has an inlet hopper  16  into which contaminated abrasive blast media  17  is deposited. Such bucket elevators are commercially available and an example of same is manufactured by Universal Industries under Model U1220 having a free flowing material capacity of 220 CFH. 
     A drive motor assembly  18  drives the bucket elevator  13  as illustrated specifically in FIG. 1 of the drawings. 
     Referring now to FIG. 2 of the drawings, the material process flow path for contaminated abrasive blast material is illustrated by flow direction arrows  19 . Contaminated abrasive blast media is delivered by the bucket elevator  13  as hereinbefore described to a primary mechanical material sized delineator sorter  20  of the invention. The sorter  20  comprises a central housing  21  having a filter drum  22  rotatably positioned within. The filter drum  22  has a central drive shaft  23  secured to an end drum closure panel  24 . The central drive shaft  23  extends from a material feed cylinder  25  within the drum  22 . The feed cylinder  25  has a screw flight  26  on the drive shaft  23  and is open at its end  27  within the confines of the filter drum  22 . A material inlet opening at  28  is formed within the feed cylinder  25  inwardly from its end in oppositely disposed relation to the open end  27 . The elevator bucket  13  deposits contaminated abrasive blasts media  17  into the feed cylinder  25  by which the screw flight  26  moves the contaminated abrasive blast media through and out the open end  27  of the feed cylinder  25  as illustrated by directional arrows  28  directly into the adjacent end area of the filter drum  22  for processing. 
     The unique filter drum  22  of the invention is made from a plurality of annular cross-sectionally triangular rods  29  aligned in spaced parallel relation to one another. The rods  29  are held in parallel alignment by a plurality of support bars  30  that extend at right angles transversely there across as seen in FIGS. 57 of the drawings. The support bars  30  themselves are radially spaced about an outer surface  22 A of the filter drum  22 . Each of the drum rods  29  are oriented with their respective “wide base”  31  of the triangle facing inwardly defining a contoured smooth interior surface  32  as best seen in FIG. 6 of the drawings. It will be apparent that the relative spacing between the adjacent rods  29  define the effective filter resolution i.e. grade or grid size of the filter drum  22 . In this example, an initial material contact area  33  within the interior of the drum  22  is of a relatively “fine” filter surface which extends approximately one-third the overall length of the drum as seen in FIGS. 4 and 5 of the drawings. The remaining drum interior surface at  34  has the respective rods  29  and their associated bases  31  spaced further apart imparting a relatively “coarse” filter surface which will allow selectively larger material particle size to pass there through. 
     Referring now to FIGS. 1 and 2 of the drawings, the multiple stage air washer  35  can be seen positioned directly below the filter drum  22  to receive selected recyclable abrasive blast media there from. The multiple air washer  35  is well known within the art and is comprised of a vertical chamber having multiple deflection angularly positioned veins  36 , each of which is positioned adjacent an outside air inlet  37  to affect a specific gravity air separation of the contaminated abrasive blast material as it cascades downwardly through the air washer. The entrained lighter weight contaminants correspondingly force upwardly through the return and removal passage  38  to be drawn off by an associated high pressure dust filter indicated by air flow path arrow  39  interconnected thereto. 
     Referring now to FIGS. 2,  3  and  7  of the drawings, a pair of filter engagement brushes  40  and  41  can be seen positioned against the outer surface  22 A of the filter drum  22 . Each of the filter brushes  40  and  41  has a central support shaft  42  with multiple sets of bristle assemblies  43  positioned thereon. The filter brushes  40  and  41  are well known within the art and are commercially available manufactured by Material Control, Inc. of Aurora, Ill. as a conveyor belt cleaner under Model No. 99. The actual configuration of the bristle assemblies  43  is characterized by helical bristle mounting channels  43 A illustrated graphically with reference only in FIG. 7 of the drawings. The brushes  40  and  41  significantly engage the outer surface  22 A of the drum  22  so as to be driven thereby as the filter drum  22  is rotated by the attached drive shaft  23 . 
     During use, given the positioning of the brushes  40  and  41  which are opposite that of the material outlet areas of the drum generally indicated at  44 . The brushes, accordingly, will effectively clean the filter rods  29  of any retaining material as the drum rotates as indicated by the broken and solid arrows  45 . 
     Referring now to FIGS. 3 and 7 of the drawings, an internal spiral material transfer screw flight  46  extends from the interior surface  32  of the drum  22  in a reverse spiral orientation to that of the screw flight  26  as hereinbefore described. The spiral transfer flight  46  directs the contaminated abrasive blast media  17  along the interior length of the drum  22  being filtered as it passes over the respective drum surface which initially filters out relatively finer, small particles indicated at  33  and then a larger size over the balance interior surface of the drum at  34 , finally ejecting large waste material unable to pass through the drum at an open end  47  indicated by directional arrows EDA in FIG. 3 of the drawings. 
     Referring now to FIGS. 1,  2  and  3  of the drawings, an apertured flow path and associated action can be described as follows. The contaminated abrasive blast material  17  is dumped into the inlet hopper  16  of the elevator  13  which as described lifts and deposits the blast media  17  into the inlet  28  of the feed cylinder  25 . The screw flight  26  then progressively moves the material there along out the open end of the cylinder  25  depositing it adjacent the drum&#39;s closed end  24  onto the “fine” filter portion  33  of the interior drum surface as hereinbefore described. 
     As noted, the contaminated abrasive blasting material is progressively moved along the inside of the filter drum  22  with the finest contaminant materials being drawn off through a fine portion and dust outlet  48  in communication with the vacuum dust control system indicated at  39 . The recyclable abrasive blast material  49  along with reduced contaminants is filtered through the coarse filter surface  34  of the interior of the drum  22  and passes directly into the air washer  35  for further separation as described previously. Finally, as noted, large contaminant material LCM is moved out the reverse open end  47  of the drum  22  as indicated by the waste ejection arrows. The now separated and reusable abrasive blast media  17  is collected and dispensed through a collection outlet  50  of the air washer  35 . 
     It will be evident to those skilled in the art that the entire separator and recovery device  10  of the invention is portable in that it can be transported by its integral base  11  by appropriate machine lift means such as a forklift (not shown) and connected to a source of power and ancillary equipment as needed and described hereinbefore. 
     While it will be apparent to those skilled in the art that some of the various individual components of the mobile separation system for contaminated abrasive blast material separation are each known and understood within the art, it is the new adaption and a new modification of the principle filter drum  22  in this environment in combination with the hereinbefore described associated elements that is the subject of the invention. 
     Only the separation and recovery device  10  of the invention as thus described allows for improved and enhanced drum filter action increasing the efficiency and capacity of a small affordable point of use abrasive blast separation systems used within the industry. 
     It will also be noted that in some applications a secondary magnet separation drum  51  shown in broken lines in FIG. 1 of the drawings can be added. Such magnet drums  51  are well known within the art and it would in this application provide a separation of ferrous and non-ferrous material in the processing of the recyclable abrasive blast material  49  and reduce contaminants entering the primary filter drum  22  of the subject invention. 
     It will thus be seen that a new and novel point of use mobile abrasive blasting media separation device has been illustrated and described and it will be apparent to those skilled in the art that various changes and modification may be made therein without departing from the spirit of the invention.