Cartridge heater and method of use

A heating apparatus suitable for use in casting high purity silicon, the apparatus comprising:

• a monolithic graphite elongated heater bar comprising a length, a first end with a generally rectangular taper-lock terminal, a second end opposite the first end, and a diameter of between about 10 centimeters to about 15 centimeters;
• a slot across the diameter beginning at the first end and running a portion of the length, and the slot dividing the heater bar into a first arm and a second arm;
• an elbow at the second end joining the first arm and the second arm together;
• 5 longitudinal slits along each a portion of a length of the first arm and a length of the second arm;
• a first electrode with a first hairpin water-filled electrical conductor in electrical communication with the first arm by a tapered fit with the terminal;
• a second electrode with a second hairpin water-filled electrical conductor in electrical communication with the second arm by a tapered fit with the terminal;
• a first compression plate securing the first arm and the first electrode;
• a second compression plate securing the second arm and the second electrode;
• an insulating insert disposed between the first arm and the second arm at the first end of the elongated heater bar;
• and
• an insulating sleeve disposed over a portion of the elongated heater bar near the first electrode and the second electrode, and isolating the heater bar from furnace insulation layers.

A method of heating a furnace volume suitable for use in producing high purity silicon, the method comprising:

• supplying an electrical current from an electrical source through a first electrical conductor;
• flowing the electrical current from the electrical conductor through a first electrode;
• flowing the electrical current from the first electrode through a first arm of a single-piece elongated heater bar and resistance heating at least a portion of the furnace volume;
• flowing the electrical current from the first arm through an elbow of the elongated heater bar;
• flowing the electrical current from the elbow through a second arm of the elongated heater bar and resistance heating at least a portion of the furnace volume;
• flowing the electrical current from the second arm through a second electrode;
• and
• flowing the electrical current from the second electrode through a second electrical conductor;
• wherein the first arm and the first electrode are secured by a first compression plate and the second arm and the second electrode are secured by a second compression plate.

A method of operating a furnace heater suitable for use in producing high purity silicon, the method comprising:

• energizing a heater element to heat a furnace volume with an electrical supply;
• operating the heater element until failure;
• denergizing the electrical supply;
• removing a first compression plate on a first electrode;
• removing a second compression plate on a second electrode;
• removing a single-piece elongated heater bar from the furnace;
• inserting a second single-piece elongated heater bar into the furnace;
• installing the first compression plate on the first electrode;
• installing the second compression plate on the second electrode;
• and
• reenergizing the electrical supply.

A heating apparatus suitable for use in producing high purity silicon, the apparatus comprising:

• a single-piece elongated heater bar comprising a length, a first end, and a second end;
• a slot beginning at the first end and running a portion of the length, and the slot dividing the heater bar into a first arm and a second arm;
• an elbow at the second end joining the first arm and the second arm together allowing all electrical connections to be made at the first end;
• a first electrode in electrical communication with the first arm;
• a second electrode in electrical communication with the second arm;
• and
• a first leg and a second leg, wherein each of the first leg and the second leg comprise an electrode interface with a tapered fit corresponding to a shape of the first electrode and the second electrode respectively.

A heating apparatus suitable for use in producing high purity silicon, the apparatus comprising:

• a single-piece elongated heater bar comprising a length, a first end, and a second end;
• a slot beginning at the first end and running a portion of the length, and the slot dividing the heater bar into a first arm and a second arm;
• an elbow at the second end joining the first arm and the second arm together allowing all electrical connections to be made at the first end;
• a first electrode in electrical communication with the first arm;
• a second electrode in electrical communication with the second arm;
• and
• a first leg and a second leg, wherein the elongated heater bar comprises a generally rectangular taper-lock terminal at the first end for electrically connecting the first leg to the first electrode and the second leg to the second electrode.