Self-blast circuit breaker and auxiliary nozzle therefor

A self-blast circuit breaker, comprising:

• a stationary contact structure;
• and
• a moving contact structure arranged to move in a longitudinal direction to engage and disengage with the stationary contact structure, the moving contact structure includes
• a puffer cylinder having a first end and a second end, and defines a puffer chamber and a thermal expansion chamber arranged between the first end of the puffer cylinder and the puffer chamber and fluidly coupled to the puffer chamber to receive insulation gas from the puffer chamber,
• a primary nozzle extending outwardly in the longitudinal direction from the first end of the puffer cylinder and arranged coaxially to the puffer cylinder, and
• an auxiliary nozzle arranged inside the primary nozzle and defining a channel therebetween, the auxiliary nozzle extends outwardly in the longitudinal direction from the first end of the puffer cylinder, and includes a first end coupled to the puffer cylinder and a second end arranged distally from the puffer cylinder and inside the primary nozzle, the auxiliary nozzle comprises
• a cylindrical body extending from the first end of the auxiliary nozzle towards the second end, the cylindrical body includes an outer surface and an inner surface defining a first elongated passage having a first diameter, and
• a nozzle throat extending from the cylindrical body to the second end of the auxiliary nozzle, and having an inner surface defining a second elongated passage having a second diameter smaller than the first diameter,
• wherein the cylindrical body defines a plurality of ports extending from the inner surface of the cylindrical body to the outer surface of the cylindrical body, the plurality of ports is arranged proximate to the nozzle throat, wherein the plurality of ports allows a flow of heated insulation gas from an inside of the auxiliary nozzle to the thermal expansion chamber through the channel.