High Temperature
Box Furnaces

BULLETIN
FH-760


2200°F
HEAVY DUTY
ELECTRIC AND GAS
HEAT TREATING
FURNACES

 

Grieve standard 2000°F Heat Treating furnaces are used for a variety of heat treating applications such as tempering, hardening, sintering or firing, including those requiring inert atmospheres. Precision microprocessor based temperature controls and energy-saving insulation maximize the performance of these rugged units. Twelve standard models from 3.9 to 96 cubic feet, built for long, hard, continuous use.

STANDARD FEATURES Back to Top
• UL LISTED CONTROL PANEL

• Standard Box Furnaces from Grieve meet the requirements of National Fire Protection Association Standard 86, Industrial Risk Insurers, Factory Mutual and OSHA standards. For some applications, such as those involving special atmospheres or hazardous locations, the above organizations require additional safety devices.

• Controls
—Digital, microprocessor based, thermocouple actuated, indicating temperature
   controller
—Modulating burner on gas furnaces
—Motor control push buttons and on-off heat switch
—LED pilot lights

 • Safety Equipment — Electric Furnace
—Adjustable, thermocouple actuated, manual reset excess temperature controller
—Separate heating element control contactors
—Door interlock switch turns off power to heating elements when door is opened;
   restores power when door is closed

 • Safety Equipment — Gas Furnace
—Adjustable, thermocouple actuated, manual reset excess temperature controller
—Electronic flame safeguard protection
—Exhauster air flow safety switch
—Recirculating blower air flow safety switch
—Purge timer
—High and low gas pressure switches
—Two pilot safety shutoff valves with leak test stations
—Two main safety shutoff valves with leak test stations (Industrial Risks Insurers
   vent valve only provided on specific request)
—Valve position indicator on main safety shutoff valves
—Over 400,000 BTU/HR safety shutoff valve interlocked with purge timer

• Construction
—3/16" steel plate reinforced furnace shell
—1/2" thick steel front plate
—Brushed stainless steel control panel face
—Powered vertical lift door
—Door hot side faces away from operator at all times
—Heavy duty ceramic hearth plates supported by firebrick piers
—1 year limited warranty

 • All equipment fully assembled and individually factory tested

 
   
SPECIFICATIONS Back to Top
NOT FOR USE WITH FLAMMABLE SOLVENTS, VAPORS OR GASES
Model
Work Space
Outside
Dimensions*
(WxDxH)
Height
Door
Open
Door
Type
Hearth
Rating
Lbs‡
Heat Input
Operating Characteristics†
Approx
Shipping
Weight
Dimensions
(WxDxH)
Volume
Cu Ft
KW
BTU/HR
Control
Accuracy
Furnace
Uniformity
Rise Time
230V 460V
HD-183618-HT 18" x 36" x 18" 6.7 54" x 71" x 75" 98" Electric 300 40 425,000 ± 0.3% ±25°F 180 min 140 min 4500 lbs
HD-243618-HT 24" x 36" x 18" 9 60" x 71" x 75" 98" Electric 360 48 450,000 ± 0.3% ±25°F 165 min 125 min 4800 lbs
HD-243624-HT 24" x 36" x 24" 12 60" x 71" x 81" 108" Electric 360 56 520,000 ± 0.3% ±25°F 155 min 120 min 5700 lbs
HD-244824-HT 24" x 48" x 24" 16 60" x 86" x 81" 108" Electric 480 65 600,000 ± 0.3% ±25°F 150 min 130 min 6500 lbs
HD-304830-HT 30" x 48" x 30" 25 66" x 86" x 87" 116" Electric 600 72 700,000 ± 0.3% ±27°F 165 min 130 min 7300 lbs
HD-306030-HT 30" x 60" x 30" 31 66" x 98" x 87" 116" Electric 700 78 725,000 ± 0.3% ±27°F 180 min 140 min 8400 lbs
HD-364836-HT 36" x 48" x 36" 36 78" x 86" x 126" 126" Air 750 78 800,000 ± 0.3% ±30°F 180 min 140 min 8600 lbs
HD-366036-HT 36" x 60" x 36" 45 78" x 98" x 126" 126" Air 850 88 850,000 ± 0.3% ±30°F 180 min 150 min 9800 lbs
HD-367236-HT 36" x 72" x 36" 54 78" x 110" x 126" 126" Air 1000 100 1,000,000 ± 0.3% ±30°F 180 min 150 min 10500 lbs
HD-484836-HT 48" x 48" x 36" 48 90" x 86" x 126" 126" Air 925 90 915,000 ± 0.3% ±30°F 180 min 150 min 9500 lbs
HD-484848-HT 48" x 48" x 48" 64 90" x 86" x 150" 150" Air 1100 110 1,100,000 ± 0.3% ±33°F 165 min 130 min 10500 lbs
HD-487248-HT 48" x 72" x 48" 96 90" x 110" x 150" 150" Air 1600 158 1,500,000 ± 0.3% ±35°F 140 min 120 min 13500 lbs
*All Models —Control panel overhang 9" right side.
  Gas Models —Combustion blower overhang 36" rear.
  Electric Models —Transformer overhang 24" rear. 		†Accuracy as percent of controller span. Uniformity at 100°F below maximum temperature. Rise Time in minutes to 100°F below maximum temperature. Tests run with empty oven and minimum exhaust. Performance will vary with load and application. See Bulletin TC-920 for additional details.
‡Uniformly distributed.
STANDARD EQUIPMENT   Back to Top
• All Models
— 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, includes floor stand to house recorder. Floor stand cannot be used for storage
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 Temperature Controller, microprocessor based, digital indicating, incorperates 99 hour 59 minute timer. Starts timing when temperature reaches set point and shuts down oven 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; alarm 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, sealed terminal boxes, recirculating blower shaft seal, high temperature door gasket, 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
 
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