System and filter for preventing contamination of particulate material in railroad car during transportation and unloading

{
  "publication_number": "US4902173A",
  "country": "US",
  "kind": "A",
  "title": "System and filter for preventing contamination of particulate material in railroad car during transportation and unloading",
  "abstract": "A system for preventing contamination of particulate material in a railroad hopper car during transportation and unloading of the material from the car, comprising transporting the material in the railroad hopper car with a filter on each of the various inlet and outlet openings of the car, then upon reaching the point for unloading, applying a vacuum to draw the material out of the car through one spout with its filter removed, while leaving the filters in place on the other openings in the car to prevent contamination of the product from external sources during transportation and unloading. The preferred filter for the railroad car spouts has a frame, a conical filter bag, and a filter bag support ring for mounting on a spout on the car.",
  "claims": [
    "1. A system for transporting and unloading a railroad hopper car loaded with particulate material while preventing contamination of the particulate material during the transportation and unloading, comprising the steps of: removing an originally installed metal cover from each originally provided opening in a hopper car to be used for unloading particulate material which has been loaded into the car prior to transportation; placing a bag filter on each opening from which a metal cover has been removed; replacing the originally installed metal cover on each opening; then transporting said car to its unloading destination with the bag filters and metal covers in place to prevent contamination of the particulate material from external sources during such transportation; thereafter removing the metal cover and bag filter from a first of said openings and attaching a vacuum hose thereto for unloading the particulate material; removing the originally installed metal cover from a second of said openings; leaving the bag filter on the second of said openings during the unloading of the material; and then unloading the particulate material from said car by applying a vacuum through said first opening and thereby drawing air in through said bag in said second opening.",
    "2. The system of claim 1, wherein: said second opening is a hatch with a metal cover on the top of said car.",
    "3. The system of claim 1, wherein: said second opening is a spout with a metal cover attached to a lower portion of said car.",
    "4. The system of claim 3, wherein: said bag filter on said second opening has a conical shape with the apex thereof extending inwardly towards the interior of said car.",
    "5. The system of claim 1, wherein: said first opening is a spout with a metal cover attached to a lower portion of said railroad hopper car.",
    "6. The system of claim 5, wherein: said second opening is a spout with a metal cover attached to a lower portion of said car.",
    "7. The system of claim 6, wherein: said bag filter on said second opening has a conical shape with the apex thereof extending inwardly towards the interior of said car.",
    "8. The system of claim 6, wherein: said car has a third opening at the top thereof with a bag filter thereon.",
    "9. The system of claim 8, wherein: said bag filter on said second opening has a conical shape with the apex thereof extending inwardly towards the interior of the car."
  ],
  "cpc": [
    "B61D 7/16",
    "B01D 46/02"
  ],
  "assignees": [
    "HENDEE ENTERPRISES INC"
  ],
  "filing_date": "1988-05-20",
  "publication_date": "1990-02-20",
  "grant_date": "1990-02-20",
  "priority_date": "1988-05-20",
  "application_number": "US-19702688-A",
  "family_id": "22727708",
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    "GB879781A",
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}