Passive thermal control of microwave furnace components

A method of thermal control of microwave furnace components, the method comprising the steps of:

• providing a microwave casket having an inner surface forming an internal cavity, the microwave casket formed at least in part of a microwave transparent material;
• providing a heatable body having an internal surface and an external surface in the internal cavity of the casket configured for receiving a metal charge, the heatable body formed at least in part of a microwave susceptor material operable to heat in response to a microwave field;
• providing a thermal control system including a fluid flow path disposed between the inner surface of the microwave casket and the external surface of the heatable body, the fluid flow path fluidly connected at a first end to an inlet formed in the microwave casket and at a second end to an outlet formed in the microwave casket;
• positioning the metal charge in the heatable body;
• generating a microwave field to heat the microwave susceptor material of the heatable body for transferring heat to the metal charge;
• and
• introducing a thermal transfer fluid into the fluid flow path via the inlet, the thermal transfer fluid being operable to flow through the fluid flow path to absorb heat from the heatable body and to transfer the absorbed heat along the fluid flow path until the thermal transfer fluid exits the fluid flow path via the outlet.

A microwave furnace comprising:

• a microwave casket having an inner surface forming an internal cavity, the microwave casket formed at least in part of a microwave transparent material;
• a heatable body disposed in the internal cavity of the casket having a crucible and a mold each formed at least in part of a microwave susceptor material such that the crucible is operable to heat in response to a microwave field to form molten metal from a metal charge positioned within the crucible and the mold is operable to heat in response to the microwave field for maintaining heat to the molten metal as the molten metal flows to the mold from the crucible;
• and
• a thermal control system including a fluid flow path disposed between the microwave casket and the heatable body along an exterior surface of both the crucible and the mold, the thermal control system operable to flow a thermal transfer fluid through the fluid flow path in at least one of a first direction to absorb heat from the crucible and transfer the absorbed heat along the fluid flow path to the mold and a second direction to absorb heat from the mold and transfer the absorbed heat along the fluid flow path to the crucible.