Apparatus and method for relieving pressure within a high pressure tank

In combination:

• a high pressure tank containing contents under pressure and having a circular throat opening through which the tank is emptied and filled and an externally-threaded annular flange surrounding the tank opening;
• a broken safety valve portion being sealingly received by said tank opening and including a spherical ball and a flow passage, said flow passage defining an outlet opening externally of said tank and an inlet opening into the tank interior, said flow passage extending generally along the central axis of said tank opening and having a ball chamber in which said spherical ball is received, the ball chamber having an outlet end aligned with said central axis and having a contoured surface positioned within the throat of the tank, said contoured surface sealingly accepting said ball as said ball is biased into sealing engagement with said chamber outlet end by the pressure of contents within said tank so that said tank contents are prevented from escaping through said valve portion flow passage;
• and
• means for acting between said tank and said spherical ball of said safety valve portion to unseat said ball from said ball chamber outlet end and thereby permit said pressurized contents of the tank to escape through said outlet of said valve portion flow passage, said means for acting including securement means adapted to be secured to said annular flange and ball-engaging means in the form of a stem attached to said securement means for movement relative thereto and for extending into the valve portion flow passage and and for extending at least beyond said contoured surface to allow said ball to be floatingly received within said ball chamber when said ball is moved out of sealing engagement with said contoured surface for moving the ball relative to the ball chamber outlet end in opposition to the pressure of said tank contents when said stem is moved relative to said securement means.

A method for relieving the pressure within a high pressure tank containing contents under pressure and having a circular throat opening plugged by a portion of a broken safety valve and an externally-threaded annular flange surrounding the tank opening, said safety valve portion including a spherical ball and a flow passage defining an outlet opening externally of the tank and an inlet opening into the tank interior, said flow passage extending generally along the central axis of the tank opening and having a ball chamber in which the spherical ball is received, the ball chamber having an outlet end aligned with said central axis and providing a contoured surface positioned within the throat of the tank, said contoured surface sealingly accepting the ball as said ball is biased into sealing engagement with said chamber outlet end of the pressure of the tank contents so that the tank contents are prevented from escaping through said valve portion flow passage, said method comprising the steps of:

• providing an apparatus including means for securement to the threads of the annular flange of said tank and associated ball-engaging means, said securement means defining a cup-shaped surface of such shape that when said securement means is operatively accepted by said annular flange, said cup-shaped surface and the outer surface of said tank bounded by said annular flange collectively define a substantially enclosed cavity, said ball-engaging means being attached to said securement means for movement relative thereto and including stem means for extending into the valve portion flow passage and for extending said stem means at least beyond said contoured surface to allow said ball to be floatingly received within said ball chamber when said ball is moved out of sealing engagement with said contoured surface for moving the ball relative to said ball chamber outlet end in opposition to the pressure of the tank contents when said ball-engaging means is moved relative to said securement means;
• positioning said stem means in relationship to said securement means so that when said securement means are operatively secured to said annular flange, said stem means are spaced from said spherical ball in said ball chamber outlet end;
• securing said securement means about the threads of said annular flange of the tank;
• and
• moving said ball-engaging means relative to said securement means to thereby move said stem means through said flow passage and into said ball chamber and thereby unseat said ball.