Image Number 2 for United States Patent #5135264.
A through flow coupler comprises two parts having intercommunicating passages therein so that fluid can flow through the two parts. A sealing member provides a fluid tight seal between the two parts when the two parts are held together in a sealed condition. A pressure sensitive device, which may comprise a frangible ring, holds the two parts in the sealed condition when the fluid pressure within the passages is below a certain value and allows the two parts to move relative to one another to a pressure relief condition so that fluid can escape from the passages when the fluid pressure within the passages exceeds said certain value. Also, mutually co-operable members, e.g. flanges, are provided to prevent total separation of the two parts when the pressure sensitive device allows the two parts to move relative to one another.