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KANTHAL APM HEAVY ROD OVERBEND ELEMENTS
Heavy duty low voltage Kanthal APM sintered iron-aluminum-chrome alloy rod/overbend elements are standard. This alloy is highly resistant to carburizing and will take the high temperatures as well. Elements are located on the sides and bottom. These are particularly suited for carbon rich atmospheres. With regular burnout in air they will provide excellent life. They rely on their protection from the atmosphere by forming a thin aluminum oxide coating on the surface of the element. Because they have a thick (6 mm) cross section, they are more resistant to breakage, cracking and embrittlement than thinner gauge wire coiled elements.
CERAMIC FIBER LIGHTWEIGHT INSULATION
2-1/2” of 2600F (1142C) low iron ceramic fiber board backed up with 2” of 1900F board and 4” of mineral wool. No asbestos or asbestos products are used in manufacture. This combination of insulation provides very efficient heat up characteristics and low heat losses.
VESTIBULE
A refractory vestibule protects the elements, supports the hearth, minimizes the door opening to promote temperature uniformity and allows for a very efficient interlocking door seal. The door seal includes a fiber gasket.
HEAVY DUTY ATMOSPHERE TIGHT CASE
The case and base are reinforced 10 gauge steel welded gas tight with full gasketing. An integrated heavy duty stand is included. The case is primed with 800F silicone paint and finished in machine enamel.
DOOR HEAT SHIELD
A heat shield is attached to the furnace door. This maintains an external door case temperature of 120F.
BUILT IN VENT HOOD
A vent hood is designed into the furnace to collect products of combustion from the burn off and unspent gases when the door opens. This vent hood terminates in a 4” diameter standard duct fitting.
PNEUMATIC LIFT DOOR
A pneumatic cylinder lifts and tightly seals the vertical door. The door rides in guide tracks. Door operation is with a pneumatic hand operated valve which allows the door to be raised or lowered with one switch.
SILICON CARBIDE HEARTH WITH MOLDED SIDES
Hearth is 1” thick silicon carbide with 1/2” high molded sides. Silicon carbide has excellent heat transfer characteristics, remains flat at high temperatures and is strong.
PEEPHOLE
A 3/4” diameter peephole allows viewing inside the furnace without disturbing the atmosphere. This includes a ball valve to shut it off and so prevent sooting of the lens.
TWO TYPES OF ATMOSPHERE SYSTEMS
Two types of atmosphere systems are offered, a plain nitrogen system and a nitrogen/propane system. In the nitrogen/propane system the propane cracks into hydrogen, carbon monoxide, nitrogen and free carbon. This counteracts the decarburizing effect of trace oxygen and water vapor at high temperatures. The flow system consists of a nitrogen and propane line. All necessary flowmeters, regulators, pressure gauges, pressure relief valves, solenoids and shut off valves are piped in a self contained flow panel which is mounted under the furnace (as shown) or under the control panel on the side of the unit. A propane fed burn off at the exit port is included. An integrated annunciator system with audible piezo type buzzer alarm and push button silencer is provided to indicate any alarm condition. There is a 1400F alarm below which to shut off the propane. A nitrogen low flow switch prevents propane from flowing unless a minimum flow is achieved. Emergency purge is activated if there is a power failure. Loss of burn off will also shut off propane and initiate a purge. This atmosphere system is designed to meet or exceed the regulations of the National Fire Protection Agency for controlled atmosphere furnaces (NFPA-86C.)
PROGRAM CONTROL SYSTEM
The standard control is a Honeywell UDC 3000 digital PID 3 mode tuning control program control with six ramps and six soaks. The power control is a either a mercury contactor or zero fired SCR. A power transformer supplies low voltage to the elements. All fuses, contactors, and controls are located in a NEMA 12 panel with a fused disconnect switch. This can be mounted either under the furnace (as shown in the photograph) or on the side. Thermocouples are inconel sheathed Type K. The control voltage is transformed to 120 volts. A Honeywell UDC 2000 digital FM approved high limit back up control with manual reset is included with back up contactors and separate thermocouple element. Furnace includes door power cut off switch. Single point power connection. Meets National Electrical Code.
TESTING AND INSTRUCTIONS
The furnace is tested to insure proper watt ratings. A complete instruction manual includes easy start up instructions, theory of operation, maintenance instructions, parts list, detailed trouble shooting guide, ladder logic diagram, panel layout, general dimension and assembly drawings. Start up service and training is optional.
WARRANTY
The furnace is warranted for one year except for elements and thermocouples (warranted for 6 months.)
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