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SHUTTLE CASE DESIGN
The case is a heavy duty fabrication which is carefully built to prevent bowing in (which can be a problem with having no bottom structure in the case.) Two bases and a complete track system are included with the furnace. Stops are built into the track system to prevent overtravel. The entire case, bases and car are primed with 800F silicone paint and finished in machine enamel.
GEARED KILN MOVER
The kiln is moved by one man with a geared manual turn wheel located on the side of the kiln. This is geared for easy movement. the kiln moves on railroad type flanged wheels. In addition there are horizontally mounted roller bearings that maintain a horizontal pressure on the track system to maintain the squareness of the kiln and prevent potential tipping.
CERAMIC FIBER INSULATION
The kiln sides and roof are typically lined with 10” of 10 pound density 2300F ceramic fiber Pyroblock insulation blocks. This provides a highly efficient insulation which has low heat storage of 2635 BTU per square foot, heat loss of 209 BTU/Square foot/hour and case temperature of 176F when operating at 2200F. This results in about a 30% energy savings over standard firebrick construction.
LAP TYPE BASE/KILN JOINTS
The seal between the kiln and the bases consists of a close tolerance lap joint. This effectively prevents radiation transfer of heat. The slight air gap (less than 1/2”) allows for an air inlet when using the optional venturi cooling system. The seal surfaces are both dimensionally stable castable refractory.
CASTABLE BOTTOM AND VESTIBULES
The bases have 8” of poured castable refractory. The material chosen is a special extremely light weight castable which still retains great mechanical strength while being reasonably energy efficient. The door vestibules and base seals are also made of t he same castable refractory. They are poured in replaceable sections which bolt onto the furnace frame.
HEAVY DUTY POWER GRADED ELEMENTS
Elements are located on the sides and two doors. These are made of coiled heavy gauge iron-aluminum-chrome alloy wire (Kanthal A-1 or equivalent.) They are mounted on alumina rods (not subject to sag like cheaper mullite rods) which in turn are mounted o n heavy ceramic blocks along the walls. The alumina rods allow the coiled elements to be completely exposed to the air. This helps maintain cool element temperature which is critical at these high temperatures. The wattage of the elements is graded top t o bottom to promote good temperature uniformity.
HORIZONTAL DOORS
There is a door at either end of the kiln. Both doors are opened while the kiln is being moved. The doors are on heavy duty single pivoted hinges. The door seal consists of folded ceramic fiber blanket which compresses against the hard castable refractor y vestibule which surrounds the door. Two mechanical latches close the door.
ZONED POWER CONTROL
The element circuits are separated into four heating zones (end-top, end-bottom, sides-top, sides-bottom.) This promotes temperature uniformity in the kiln. Each of these zones is typically controlled with percentage timers that control time on and time off for the elements. Optional SCR power controls are digitally biased. Separate 4 loop PID control is also available.
DIGITAL PID CONTROL AND HIGH LIMIT SYSTEM
The standard control is a Honeywell UDC 2300 digital PID 3 mode tuning control. All fuses, transformers, contactors, and controls are located in a NEMA 12 panel with a panel mounted fused disconnect switch. Power control is normally mercury contactors. Thermocouple type is typically type R. Thermocouple break protection is included. Limit switches shut off furnace power if the car is lowered. Control voltage is transformed to 120 volts. A Honeywell UDC 2300 digital high limit back up control with manual reset, back up contactors and separate thermocouple is standard. The control circuit and each power branch circuit are fully fused. Single point power connection. Meets National Electrical Code.
TESTING AND INSTRUCTIONS
The furnace is power tested to insure circuit integrity. A complete instruction manual includes easy start up instructions, theory of operation, maintenance instructions, general dimension and layout drawings, assembly drawings, 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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