Safety vent discharge arrangement

Claim 1

A safety vent structure for a railway tank car comprising: a. a body defining a chamber having first and second end portions respectively defining first and second openings into said chamber; b. said body being mounted in association with said tank so that said second opening permits fluid communication between said chamber and the interior of said tank; c. an annular seat associated with said first end portion adjacent said first opening; d. a frangible element mounted on said seat in closing relationship to said first opening; e. a retainer ring fastened to said annular seat for holding said frangible element in fluidtight association with said first opening; f. a closure cap of generally inverted U-shaped diametrical cross section disposed exteriorly of said retainer ring, said closure cap having a base in closing relationship to said retainer ring and leg portion overlapping and spaced from said retainer ring; and g. substantially horizontal pin means extending through a pair of apertures in said retainer ring and through a pair of vertically elongated slots in said leg portion of said closure cap so as to permit movement of said closure cap away from said retainer ring upon an increase in pressure in said chamber beyond the rupture limits of said frangible element and return of said closure cap to a closing relationship with said retainer ring after reduction of said chamber pressure.