Downstream injection nozzle for puffer circuit interrupter

A nozzle structure for a puffer type interrupter;

• said puffer type interrupter including a pair of separable contacts, a gas flow directing nozzle of insulation material which concentrically surrounds said pair of separable contacts for directing a flow of gas through arcs drawn between said pair of separable contacts as they separate;
• said gas flow directing nozzle having open opposite ends;
• gas pressure generating means connected to one of said opposite ends for producing a flow of gas in a single direction, and through said nozzle from said one of its said opposite ends to the other of said opposite ends at least while said pair of separable contacts are opening;
• said flow of gas in a single direction being generally along the axis of said nozzle and said pair of contacts moving generally along the axis of said nozzle when said pair of contacts separate;
• said nozzle having a throat restriction generally upstream of the region of contact separation between said pair of separable contacts;
• and a plurality of ports extending into the interior surface of said nozzle at an axial location generally downstream of said throat restriction;
• one end of said ports being connected to regions upstream of said nozzle restriction and injecting a turbulent flow of relatively cool gas downstream of said nozzle during the separation of said pair of contacts;
• the other end of said ports being connected to said gas pressure generating means;
• said gas pressure generating means including a relatively movable piston and cylinder connected to said pair of separable contacts, whereby a flow of gas is produced through said nozzle when said pair of separable contacts is operated;
• said nozzle including generally axially extending channels therein for connecting said other end of said plurality of ports to said gas pressure generating means.