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LOW MASS INSULATION
The furnace is insulated with 6 inches of low “K” factor ceramic fiber and mineral wool insulation. Two inches of this insulation consists of a removable molded element/insulation module that lines the interior of the furnace. It is not brittle and so maintenance is minimal. The insulation has a very low thermal mass and hence heats up very quickly. Heat up to 1800F (980C) will take approximately 45 minutes. No asbestos is used.
CERAMIC FIBER MOLDED ELEMENTS
Elements are embedded in ceramic fiber and are made of coiled iron-aluminum-chrome alloy. There are three separately controlled zones of heating with separate elements, one on each end and one in the center. Special versions feature even more zones than the standard three for greater uniformity or for special applications. The elements are preoxidized (which is what protects this particular alloy from the high temperatures.) Elements are replaced easily. The elements are evenly spaced along the entire surface of the interior and hence will provide the maximum in temperature uniformity by uniformly radiating along the surface of the tube. The insulation is fitted with vestibules at both ends. These protect the elements and help hold the tube in place. They hold heat in around tubes that are inserted into the furnace. The vestibules split open with the furnace case.
BENCH MOUNTED CASE CONSTRUCTION
The furnace case is constructed of welded 10 and 14 gauge steel. The case is primed with 800F silicone paint and finished in machine enamel. The hinged case splits open in the center from one side and latches on the other side.
DIGITAL PID CONTROL SYSTEM
The standard control system uses three separate Honeywell UDC 2300 digital PID 3 mode controls. One zero fired SCR for each zone is used for precise power control. Thermocouples are Type K with inconel sheathing. Thermocouples are typically located inside the tube and the controls are tuned to prevent overshoot. A Honeywell UDC 2300 digital high limit back up control with manual reset, back up contactors and separate thermocouple is included. The control voltage is transformed to 120 volts. All fuses, transformers, contactors, and controls are located in a detached bench mounted NEMA 1 panel. Control and power circuits are branch fused. A NEMA 13 lighted On/Off switch is included. Customer must connect fused power supply to single point on panel.
TESTING AND INSTRUCTIONS
The furnace is power tested to insure proper watt ratings. The controls are fully calibrated and the control system completely tested. A complete instruction manual includes start up instructions, theory of operation, maintenance instructions, parts list , and a detailed trouble shooting guide. A ladder logic diagram and panel layout are prepared on CAD for easy readability.
WARRANTY
The furnace is warranted for one year except for elements and thermocouples (warranted for 6 months.)
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