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FURNACE CONSTRUCTION
The furnace is made of polygonal heater sections with a stainless steel wrap around casing. These are supported in heavy metal frame that completely supports and protects these heaters.
BELL/SHUTTLE LIFT DESIGN
The furnace is lifted up by an integral electric hoist which is mounted on a shuttle device. This shuttle device, made of structural steel, shuttles between two separate bases. The movement of the shuttle device is by hand operation. Clamps hold the furnace shuttle in place.
FURNACE/RETORT BASE
One base assembly has an insulated retort plug bottom. The retort bell jar cover goes over this plug bottom and gets bolted down to the bottom with swing away quick release clamps. The bottom has all the water cooling channels, thermowells and gas atmosphere connections so that these do not need to move.
“PARKING” BASE
A separate base is provided to “park” the heated furnace.
INSULATION SYSTEM
The furnace is insulated with 2-1/2” of low K factor refractory firebrick with 2” of backup mineral wool. No asbestos or asbestos products are used.
IRON-ALUMINUM-CHROME ELEMENTS
These are excellent for high temperature applications. An oxide coating protects the element. The elements are supported in proprietary ceramic element holders. These provide perfect support for the coiled element as well as excellent radiating characteristics. The smooth surface prevents premature failure of the element as it expands and contracts. Elements are evenly spaced around the perimeter of the furnace and are zoned.
HEARTH
The top of the insulated plug is designed to take up to the rated load. If a fan is used there is a grid above fan.
BELL ATMOSPHERE “TOP HAT” RETORT
There is an alloy round atmosphere tight retort designed for combustible or inert low dew point atmospheres. The type of alloy used is dependent on the temperature and application. Inlet and outlet are mounted through the bottom base assembly. The base features an insulation plug which is completely covered with alloy so that no water vapor can get trapped in the insulation and outgas to the chamber. There is a silicone rubber “O” ring seal around the perimeter of the retort. This is cooled by water which runs in an enclosed channel around the perimeter of the base. The retort is secured with quick release bolt down latches. This forms an extremely tight seal and allows very low dew point operation.
ATMOSPHERE SAMPLE PORT
A sample port is provided. There is a valve to close this off when not in use. This is used to sample the atmosphere for oxygen, hydrogen, dew point, etc.
ATMOSPHERE CONTROL
A variety of atmosphere control systems can be provided. See Bulletin H2 which describes the hydrogen flow control system or Bulletin MPH for information on a mixing panel for forming gas. In addition, simple regulators/flowmeters can be provided for inert gas use.
DIGITAL PID CONTROL SYSTEM
The standard control is a Honeywell UDC 2300 digital PID 3 mode tuning control. All fuses, transformers, contactors, and controls are housed in a floor mounted NEMA 1 panel. If hydrogen is used then a purged NEMA 12 control panel is standard. Quiet, long life mercury power contactors are standard, but the SCR power control option is recommended (preferably with zoned control for high uniformity.) The thermocouple is Type K and is located inside the retort for accurate control of process temperature. Thermocouple break protection is included. Control voltage is transformed to 120 volts. A NEMA 13 lighted On/Off switch is included. The control circuit and each power branch circuit are fully fused. Honeywell UDC 2300 digital high limit back up control with manual reset, back up contactors and separate thermocouple included. NEMA 1 panels must be connected to a fused power supply. NEMA 12 panels have a fused disconnect switch.
TESTING AND INSTRUCTIONS
Furnace is completely tested at the factory. A complete instruction manual includes easy 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, retort and thermocouples (warranted for 6 months.)
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