Circuit interrupting device

An improved circuit interrupting device of the type in which a movable contact moves away from a stationary contact following melting of a fusible element, and in which a flow of dielectric fluid is directed at an elongating arc established between the contacts;

• wherein the improvement comprises:
• fusible diaphragm means for normally preventing the flow of the fluid and for normally preventing movement of the movable contact;
• and
• means, including the fusible element, for normally shunting away from the diaphragm means the current flowing through the device until the fusible element melts, at which time all of the current flowing through the device flows in and melts the diaphragm means.

An improved circuit interrupting device of the type wherein, after a fusible element ceases to be intact in response to a current of a predetermined magnitude through the device, a movable contact is moved away from a stationary contact;

• and wherein a flow of dielectric fluid is directed at an elongating arc established between the contacts;
• the improvement comprising:
• (a) fusible diaphragm means for normally preventing the flow of the fluid;
• and
• (b) shunting means for
• (i) normally directing through the fusible element, and normally shunting away from the diaphragm means, a majority of the current flowing through the device, and
• (ii) after the fusible element ceases to be intact, directing through the diaphragm means all of the current flowing through the device.

An improved circuit interrupting device of the type wherein, after a fusible element ceases to be intact in response to an overcurrent through the device, a movable contact is moved away from a stationary contact;

• and wherein a flow of dielectric fluid is directed at an elongating arc established between the contacts;
• the improvement comprising:
• (a) fusible diaphragm means for normally, when intact,
• (i) preventing the flow of the gas, and
• (ii) preventing movement of the movable contact, the diaphragm means being of a type which ceases to be intact in response to the flow therethrough of current in excess of a predetermined magnitude;
• and
• (b) shunting means for
• (i) normally directing through the fusible element, and normally shunting away from the diaphragm means, a majority of the current flowing through the device so that a minority of the current flowing through the device normally flows through the diaphragm means;
• the minority of the current having a magnitude no greater than the predetermined magnitude;
• and
• (ii) after the fusible element ceases to be intact, directing through the diaphragm means the entire current flowing through the device, the magnitude of the entire current through the device exceeding the predetermined magnitude.

An improved circuit interrupting device, comprising

• a reservoir of pressurized dielectric fluid;
• first and second ports in the reservoir from which the fluid flows;
• first and second stationary contacts adjacent a respective port;
• first and second movable contacts biased for movement away from a respective stationary contact to define respective gaps, each gap being so positioned as to receive fluid flowing from a respective port;
• first and second fusible diaphragm means for normally, while intact,
• (a) closing a respective port, and
• (b) preventing movement of a respective movable contact;
• and shunting means, including a fusible element, for
• (a) normally shunting current flowing through the device away from both diaphragm means, and
• (b) after the fusible element ceases to be intact, directing through both diaphragm means all of the current flowing through the device so that both diaphragm means cease to be intact to open both ports and permit movement of both movable contacts, respective arcs being formed in the gaps.

An improved circuit interrupting device of the type in which a first contact and a second contact move relatively apart following the melting of a fusible element, and in which a flow of dielectric fluid is directed at an elongating arc established between the parting contacts;

• wherein the improvement comprises:
• diaphragm means for normally preventing the flow of the fluid;
• and
• means for shunting away from the diaphragm means current flowing through the device as long as the fusible element is unmelted, and for directing such current through the diaphragm means to melt the diaphragm means after the fusible element melts.