Chamber and hot zone
The chamber is designed to accommodate up to twelve feeding wires. The wires will pass first through a stainless steel guide tube located at the top, and will then move into the higher (2500°C max.) temperature furnace zone. The wires comes up to the annealing temperature in this section. The hot zone is a highly uniform temperature zone, creating repeatable and reliable heating. Next the wire will enter the cooling zone at the bottom with a temperature gradient set so the cool down rate is controlled to meet process specifications.
The furnace chamber is double walled, round or rectangular, and is fabricated from high grade stainless steel. The furnace chamber is welded and polished.
The Hot Zone is a round design using a Tungsten Mesh Heating Element and Tungsten & Molybdenum Refractory Shielding (other materials available). The usable, uniform, +/-5°C hot zone is 2.75″ ID X 20.0″ long and is designed to easily reach a temperature of 2500°C (4500F). This heat zone arrangement allows for fast heat up and cool down rates, allowing minimal down-time for shut-down periods.
Hot zone temperature is measured by an optional pyrometer using the sight window as the sight path for temperatures above 1000°C.
Power supply and controls
All instruments, contactors, transformers and controllers are mounted in a single space saving enclosure. The main step-down transformer to supply power to the heating elements has extra power for fast ramp rates and is equipped with two voltage taps to match the element resistance as it ages. A set of water cooled power cables supplies the power to the heating elements from the main step down transformer. A set of amp and voltmeters allows monitoring of the power usage.
The furnace temperature is controlled by a programmable temperature controller using a Type “C” thermocouple or two color optical pyrometer to measure temperature. Multiple temperature profiles can be stored to simplify running different processes.
An HMI system is available as well, check options for more information.
Process gas system
The furnace system is designed to operate in an Inert Gas or reducing gas environment. The chamber runs under a slight positive pressure to keep oxygen from entering. A relief valve and a compound gauge are located on the top of the furnace body.
The gas system provides a pressure differential keeping air from flowing into the wire feeding tubes and chamber. Gas flow rates are controlled using flow meters on the control panel. An oxygen monitor with audible alarm is used to monitor the amount of oxygen present in the chamber (for inert environments). Once the gas purge is complete and oxygen content is low enough, heat can be applied. If during any time the oxygen level inside the chamber exceeds a preset level, an alarm will sound and the hot zone power will be shut off. An emergency gas system also is supplied in the event the regular gas supply fails.
Water cooling manifold
The water manifold provided with this system is designed to adequately cool the furnace and power cables. To insure proper flow, a water flow switch is installed with a light for visual indication. In the event water flow is disrupted for more than 5 seconds when the furnace is operating, power will be disconnected from the heating elements. The water manifold has several circuits supplying water to the various parts of the furnace. Each one of these can be manually adjusted to allow each circuit just the proper amount of flow to save water.
||35 kVA (depending on maximum temperature), 380-480Vac/3ph./50-60 Hz (other voltages available)
||7-10 G.P.M. @ 70°F (20°C) and 50 P.S.I.G. (3.4 bar)
||Inert or flammable Gas, 70 lpm @ 40-60 P.S.I.G. (2.75 – 4.1 bar)
||Inert gas, 50 lpm @ 30 PSI (2 bar) Min, 70 PSI (4.8 bar) Max.