Thermal Technology Llc

Thermal Technology?s fiber drawing furnaces are designed for operation to 2400?C with preforms up to 61 mm in diameter. The fiber drawing furnace features a simplified long-life, high-purity graphite resistance element which delivers concentrated heat through a linear graphite tube (available with a split liner for altering the hot zone profile) that serves to protect the element and control inert gas flow. Encapsulated graphite felt insulation surrounds the heating element. Protective inert gas flow routing is simple and effective with top and bottom gas screens, top adjustable iris assembly and bottom water-cooled slide door assembly. Safety interlocked top and bottom plugs permit convenient evacuation and backfilling of the furnace prior to operation. A 30 kVA power supply is also included, complete with a separately housed main transformer in a NEMA enclosure and 10 feet (or longer) of flexible power cables to couple the furnace to the transformer Our fiber drawing furnace, coupled with Thermal Technology?s Gas Purification and Oxygen Analyzer will produce excellent element life in excess of 1000 hours. Operating Gas The fiber drawing furnace MUST be operated with an inert gas (helium, argon or an argon/helium mixture). The gas must be dry and oxygen-free -- less than 1 PPM water and oxygen. The use of Thermal Technology?s Gas Purification System (Model IGP) is recommended. Entry and Exit Ports Top port is closed with a single sliding water-cooled door when there is no preform in the furnace. In open position, the door provides an opening of 2.5? (63mm). The bottom port is closed with dual sliding water-cooled doors with a minimum opening of 0.25? (6mm). Replaceable iris diaphragm assemblies are available as options for both the top and bottom ports. The irises have an adjustable range of 0.2? (5 mm) to 2.5? (63 mm). Radial Ports Two 1 ⅛? - 16 threaded ports are provided to view the center of the furnace hot zone. Both ports view the heating element through a 0.31? (8 mm) diameter sighting hole. One port is located 45? to the right of the front of the furnace, the other 90? to the left (135? apart). A window is installed in the left port which views through the element. The right port views the exterior of the element for accurate temperature control using an optional radiation pyrometer. This port is plugged but will accept the standard window assembly. Gas Ports Ports with compression fittings for ?? (6 mm) outside diameter tubing are provided for gas inlets and venting. All fittings extend toward the rear of the furnace and serve the following purposes: ? Top gas curtain, inlet, with quick disconnect. ? Bottom gas curtain, inlet, with quick disconnect. ? Radial purge, inlet. This port admits inert gas into the thermal insulation area for purge prior to beginning furnace heat-up. ? Radial pressure monitor. This port allows connection of a very low pressure gauge (1 inch water) to monitor interior pressure with respect to the exterior.