High Temperature Box Furnaces

BULLETIN FH-760 2200°F HEAVY DUTY ELECTRIC AND GAS HEAT TREATING FURNACES

Standard Features Specifications Standard Equipment Additional Equipment

MODEL HD-183618-HT ELECTRIC

STANDARD FEATURES  Back to Top

Standard Electrical Characteristics
— 208 volts, 3-phase, 60 Hz
— 230 volts, 3-phase, 60 Hz
— 460 volts, 3-phase, 60 Hz
— Other electrical characteristics available

Wall and floor insulation, 9" thick, consisting of:
— 4-1/2" of 2500°F insulating firebrick
— 2-1/2" of 2300°F insulating firebrick
— 2" of 1900°F, 18-1/2 lbs/cf block insulation

Roof insulation, 8" thick, consisting of:
— 1" of 2600°F, 8 lbs/cf ceramic fiber blanket
— 5" of 2300°F, 8 lbs/cf ceramic fiber blanket
— 2" of 1700°F, 8 lbs/cf ceramic fiber blanket

Furnace shell is made of 3/16" thick steel plate reinforced with structural steel. Doorsill constructed from firebrick to protect furnace during loading. Ceramic hearth plates are 2" thick and supported by firebrick piers. Soft insulation on door provides an excellent heat seal by pressing against the vestibule refractory and the 1/2" thick steel front plate. Exterior painted with Trilite Green enamel.

Each features completely wired, side access UL listed control panel assembled on the furnace enclosing terminals for incoming power, temperature controllers, push buttons and pilot lights.

Electric Models
Safety devices as listed at the top of this bulletin. Heating element contactors electrically interlocked with door to shut off power to heaters as door opens and restore power when closed. Heating elements located at sides, rear and under hearth. High temperature alloy rod overbend heating elements hanging from the vertical walls by "J" hooks. Rear mounted power transformer feeding low voltage heating elements.

Gas Models
— 1,000 BTU natural gas at 2 psig pressure:
    1" NPT inlet up to 800,000 BTU/HR;
    1-1/4" NPT 850,000 to 1,100,000 BTU/HR;
    1-1/2" NPT at 1,500,000 BTU/HR
— Other gas characteristics available

Safety devices as listed at the top of this bulletin. Automatic pre-ignition purge period and push button electric ignition contributes to ease of operation. Modulating gas burners fire beneath hearth from opposing sides to circulate heated air through work space. Gas burners protected with electronic flame safety relay. Door interlock switch drives main burners to low fire when door is opened and restores control when door is closed.

ELECTRIC DOOR
Door pivots upward above furnace, clearing front for easy loading. In the closed position, full door weight seats door firmly against furnace face. Structural steel pivot arms are supported at furnace sidewalls by bearings and connected to a heavy duty electromechanical actuator. The door is controlled by a switch at the furnace control panel.

AIR DOOR
Door rises vertically in front of the furnace hanging from heavy duty roller chain, sprockets, shaft and pillow block bearings. In the closed position, rollers at the sides of the door engage support brackets to force the full door weight against the furnace face. Large diameter air cylinder rotates support shaft to lift the door. The door is controlled by a manual air valve with supply filter, lubricator and regulator.

ADDITIONAL EQUIPMENT AVAILABLE  Back to Top
See Bulletin TC-960 for modifications and other optional equipment.

• Programmable Temperature Controller, microprocessor based, digital indicating, thermocouple actuated, in lieu of standard controller
  Option PTC3



• Recording Thermometer, thermocouple actuated, 24-hour, 10" diameter circular chart used in conjunction with standard controller
  Option RT



• Programmable Recording Temperature Controller, microprocessor based, thermocouple actuated, digital display, 24-hour, 10" diameter circular chart, in lieu of standard controller
  Option PRTC3



• Digital Timing System, incorporated into standard temperature controller, 99 hour 59 minute range, starts timing at temperature set point and shuts down furnace at end of set time
  Option DTS3



• Shut Down Timer, with continuous "hold" feature; 1, 5, 10; or 30 hour range
  Option SDT



• Batch Timer, for uniformly timing batch operations. Continuous alarm with door interlock; alarms at end of preset time period until door is opened or timer reset; 1, 5, 10 or 30 hour range
  Option BT



• Alloy Hearth Tray, made of heat resisting high temperature alloy, for protecting ceramic hearth plates from impact and heavy loading
  Option AH



• Inert Atmosphere Construction, electric only, includes continuously welded shell, inert atmosphere gas inlet and outlet, high temperature door gasket, sealed terminal boxes, optional forced cooling systems are available at additional cost
  Option IAC
  
  
• Inert Atmosphere Inlet Piping, with indicating flow control and manual gas valve. Specify atmosphere
  Option IAIP