Puffer type gas circuit breaker

A puffer type gas circuit breaker comprising:

• a vessel being filled with insulating gas;
• a stationary-side main contact and a movable-side main contact that being provided in the vessel and on the same axis so that they position to face each other in opposite directions;
• a stationary-side arcing contact and a movable-side arcing contact that being concentrically provided inside the stationary-side main contact and the movable-side main contact respectively;
• a puffer cylinder, the movable-side arcing contact being provided on the top end of the puffer cylinder;
• a puffer shaft having a puffer chamber-side exhaust hole and an operation rod-side exhaust hole, the puffer shaft being concentrically provided inside the puffer cylinder;
• a closing member closing the operation rod-side exhaust hole;
• a puffer piston sliding on the inner surface of a space formed by the puffer cylinder and the puffer shaft;
• a flow control section having an opening part, the opening part is communicable with the puffer chamber-side exhaust hole, the flow control section being provided on the puffer piston and in a puffer chamber formed by the puffer cylinder and the puffer shaft and the puffer piston;
• and
• an insulating nozzle being provided concentrically with the movable-side arcing contact, the insulating nozzle blows an insulating gas compressed within the puffer chamber to the arc produced between the stationary-side arcing contact and the movable-side arcing contact;
• wherein, when an interruption operation is completed,
• a space having a given extent is formed in the puffer chamber;
• the puffer chamber-side exhaust hole communicate with the opening part;
• and the closing member closes the operation rod-side exhaust hole.