Device for blocking or releasing fluid flow

A valve for controlling fluid flow therethrough, comprising

• valve body means defining a cavity therein and first and second opposing fluid flow passages communicating with said cavity, for fluid flow between said first and second opposing fluid flow passages through said cavity, said valve body means further defining a first tapered metallic valve seat in said cavity surrounding said first fluid flow passage and a second tapered metallic valve seat in said cavity surrounding said second fluid flow passage, said valve body means further defining a conical recess in said cavity intermediate said first and second tapered valve seats, said recess having its central axis substantially perpendicular with respect to the direction of fluid flow between said first and second fluid flow passages,
• a valve ball in said cavity for movement into sealing engagement with said first and second tapered metallic valve seats by fluid flow between said first and second fluid flow passages to prevent further fluid flow through said cavity,
• a release bar extending through an opening in said valve body means opposite said conical recess, said release bar being slidably mounted for movement into said cavity in a direction substantially perpendicular to said fluid flow between said first and second opposing fluid flow passages to contact said valve ball and press said valve ball into said conical recess, thereby permitting fluid flow through said cavity and wherein said valve body means further defines a fluid passageway from said recess to said cavity to equalize pressure within said recess when said valve ball is positioned in said recess, thereby facilitating movement of said ball from said recess into engagement with said first or second tapered metallic valve seats upon movement of said release bar away from said recess.