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Bottom operable tank car valve assembly having shear plane

  • US 4,141,535 A
  • Filed: 06/08/1977
  • Issued: 02/27/1979
  • Est. Priority Date: 01/28/1976
  • Status: Expired due to Term
First Claim
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1. A bottom operable lading valve assembly for tank cars comprising:

  • a valve body adapted to be integrally attached to an opening in the bottom of a tank;

    said valve body having a valve body opening therein;

    a retainer fitting within said valve body opening, including a flange portion and means for attaching said retainer to said valve body, said retainer including at least one retainer rib extending radially inwardly from said flange portion and terminating in a retainer connection portion having a center hub;

    a valve plug movable between open and closed positions relative to a circular plug seat located within said valve body opening, a housing affixed to said valve body with fastening means comprising a shear plane;

    said housing having a generally vertical housing opening therein into which a rotatable valve operator is mounted comprising a lower tool connection portion, a shaft portion and an upper operating portion;

    said center hub slidingly engaging said upper operating portion to allow rotation of said upper operating portion while maintaining said upper operating portion spaced from said valve body and vertically fixed;

    said upper operating portion having upper operator threads for engaging a valve plug operating stem depending from said valve plug having stem threads which engage said upper operator threads;

    said upper operating portion and said stem terminating above said shear plane;

    said shaft portion including separating means for separating said valve operator shaft below said shear plane in the event said housing should shear off along said shear plane;

    whereby rotation of said valve operator in a first direction causes said plug to move toward open position;

    closure plug stop means which engage when said plug assumes the full open position; and

    whereby rotation of said valve operator in open position in a second direction, opposite to said first direction, causes said plug to move to a closed and seated position; and

    whereby when said closure plug is in closed position severe impacts to said outlet will cause said housing and a portion of said valve operator shaft to separate from said outlet generally below said shear plane, thereby tending to maintain said valve plug in the closed, seated position and maintain any lading within the tank during and after such impact.

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