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NEI's Laboratory Furnace Products
Muffle Furnace Model FD -204-CB
Furnace Description
The Type FD Muffle Furnaces operate on A.C. or D.C. at the usual Line Voltages up to 250Volts. Temperature is controlled by a Precision microprocessor control system. Automatically compensates for variations in heat load, line voltage, ambient temperature. Microprocessor Controller/Solid State Relay control System. Digital temperature setpoint and readout. Smoothly regulated temperature control. Ramp at a programmed heating. Ramp and hold at predetermined setpoint. Stainless Steel casing. Heat off switch allows monitoring only. Uses standard thermocouple. Fully pre-wired. Selectable control mode. Automatic tuning. Nonvolatile memory. Manual Control option, with bumperless transfer.
Heating Chamber: 7-1/4" Wide X 5-1/4" High X 14" Deep
Overall Size: 23" Wide X 29" High X 25" Deep
Total Power: 3.4 Kilowatts
Voltage: 240 Volt - Single phase - 15.1 Amps or Model-120 Volt - Single phase - 29 AmpsHistory
Hoskins Manufacturing invented the FD 204 Muffle Furnace in 1920, the beginning of the Industrial revolution in the Automobile Manufacturing capitol of the world Detroit, Michigan. Records of the furnaces show the customers to be Entrepreneurs such as Henry Ford, Thomas Edison, Fisher, Packard Motor, Cadillac, Dodge, Universities of every State in the union, Metallurgical Laboratories, and Steel Treaters around the world. The design has been refined four times in the last 75 years, and been used as the standard by which all others are measured. In 1991 National Element, Inc. purchased the Hoskins furnace line, and began manufacturing the furnaces in Detroit.
Operation FD-204 Muffle furnaces are designed to operate on one voltage only. This makes it possible to use the heaviest possible wire for each voltage application. For 120 volt operation the heating element is made of .081" diameter Chromel® "A". In the 240 Volt unit the wire diameter is .051" in diameter. This feature of supplying furnaces with heating elements designed for a specific voltage is another example of sound engineering principals, which are incorporated in National Element furnaces. The FD furnace should not operate above 1000°C (1832°F), it's safe maximum temperature, even for a short time. If Temperature is allowed to exceed 1000°C even once, the life of the heating element will be materially reduced. If higher temperatures are desired, see FH model in our catalog.
Caution
Sulfur ores should not to be treated in the Type FD furnace as the sulfur fumes penetrate the muffle walls and reduce the life of the heating elements. When working with salts (common salt, potassium cyanide, saltpeter, etc.), that fuse below the working temperature of the furnace, care should be taken not to spill any on the floor of the muffle. The fused salt penetrates the muffle wall and injures and/or contaminates the heating element. When working with such material, it is advisable to use a metal tray on the floor of the furnace.
Repairs
In case of a burnout, the operator can rewind the core of the furnace himself. New heating element coils are furnished of definite length and resistance for each type of furnace. When ordering heating elements or other parts of the furnace always state the Type, Serial No., Voltage, and Current, this data being given on the nameplate of the furnace case. The heating element of the FD furnace is easily accessible for repair. In the muffle design, remove the nut that holds the terminal cover in place and disconnect the heating units from the large brass screws, and ground center connection. Remove the screws that hold the front head to the steel case and the front head, including throat brick. Door guides and shelf may then be removed. The muffle, including the heating unit, can now be withdrawn. The procedure in rewinding the muffle is a simple task. Pass one end of the heating element through the small hole at one end of the muffle groove, wind the coil element in the grooves and fasten the other end of the wire in a similar way.
Quality
FD-204 Muffle Furnaces are still hand built, as they were 75 years ago. Our inspectors use a 20-point checklist on every aspect of manufacture. The furnaces are built using the finest materials available, and built to last. The most vital part of any electric furnace is the heating element, which when properly designed and manufactured from quality materials, will provide years of useful heating life. National Element, Inc. uses Chromel® "A", a nickel-chromium alloy manufactured by Hoskins Manufacturing. The first name in Electric Resistance Heating Alloys. Dependability is a quality the FD-204 is well known for 75 years of service. Equipment of this quality only survives if they are of the highest grade and reliability.
Environmental
Electric furnaces are clean, safe, and better for our environment. With all the EPA issues being addressed today, ELECTRIC heat is the only true answer. Exhaust fumes from gas or oil is nonexistent. Ozone damage is not an issue with an electric furnace. Electric heat is efficient and clean. Recycle your heating elements, send us your old elements for re-cycling, and re-melting and save energy for the future.
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