2000°F HEAVY DUTY ELECTRIC AND GAS HEAT TREATING PIT FURNACES
Grieve standard 2000°F Pit Furnaces are used for a variety of heat treating applications including those requiring inert atmospheres where overhead handling equipment is used. Full opening door exposes entire work space for easy loading. Precision microprocessor based temperature controls and energy-saving insulation maximize the cost efficiency and performance of these rugged units. Nine standard models from 3 to 45 cubic feet built for long, hard, continuous use. Ideal for severe service applications - load capacities to 1200 lbs.
Standard Pit 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
—Easy-to-see pilot light
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
—Combustion air blower with 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 top plate
—Brushed stainless steel control panel face
—Powered rear hinged door
—Energy-saving lightweight ceramic fiber insulation reduces operating
costs
—Insulating refractory floor to support heavy loads
—Excellent temperature uniformity throughout work space
—Fast heat-up and cool-down
—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
Model
Dimensions (WxDxH)
Volume Cu Ft
KW
BTU/HR
Control Accuracy
Furnace Uniformity
Rise Time
230V
460V
PT-181818
18" x 18" x 18"
3.4
55" x 50" x 54"
69"
Electric
250
15
165,000
± 0.3%
±25°F
75 min
65 min
1550 lbs
PT-181818
PT-181824
18" x 18" x 24"
4.5
55" x 50" x 60"
75"
Electric
300
18
200,000
± 0.3%
±25°F
75 min
55 min
1650 lbs
PT-181824
PT-242424
24" x 24" x 24"
8.0
61" x 56" x 60"
81"
Electric
430
26
285,000
± 0.3%
±25°F
60 min
45 min
2050 lbs
PT-242424
PT-242430
24" x 24" x 30"
10
61" x 56" x 66"
87"
Electric
500
30
330,000
± 0.3%
±25°F
60 min
45 min
2200 lbs
PT-242430
PT-303030
30" x 30" x 30"
16
67" x 62" x 67"
93"
Electric
600
36
400,000
± 0.3%
±25°F
60 min
45 min
2700 lbs
PT-303030
PT-303036
30" x 30" x 36"
19
67" x 62" x 73"
99"
Electric
700
39
425,000
± 0.3%
±25°F
65 min
45 min
2900 lbs
PT-303036
PT-363636
36" x 36" x 36"
27
73" x 68" x 74"
106"
Air
900
52
575,000
± 0.3%
±30°F
50 min
40 min
3500 lbs
PT-363636
PT-363648
36" x 36" x 48"
36
73" x 68" x 86"
118"
Air
1050
62
675,000
± 0.3%
±30°F
50 min
40 min
3950 lbs
PT-363648
PT-363660
36" x 36" x 60"
45
73" x 68" x 98"
130"
Air
1200
72
800,000
± 0.3%
±30°F
50 min
40 min
4400 lbs
PT-363660
*All Models—Control panel overhang 9" right side. Gas Models—Outside depth increases by 10".
Combustion blower overhang 36" 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 furnace. Performance will vary with load and application. See
Bulletin TC-920 for additional details.
‡Uniformly distributed.
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 insulation, 7" thick, consisting of:
— 5" of 2300°F, 8 lbs/cf of ceramic fiber blanket
— 2" of 1700°F, 4 lbs/cf of ceramic fiber blanket
Floor insulation, 6-1/2" thick, consisting of:
— 4" of 2300°F insulating castable
— 2" of 1900°F, 18-1/2 lbs/cf block insulation
Furnace shell is made of 3/16" thick steel plate reinforced with structural
steel. Powered door supported at rear by heavy duty shaft and pillow block bearings.
Open door exposes entire work space for easy loading. Floating door construction
provides an excellent heat seal by pressing soft insulation against the 1/2" thick steel top 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 on 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. High temperature alloy wire heating elements
supported in vacuum cast ceramic fiber. Heating elements located at four side walls.
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 1,000,000 BTU/HR;
— Other gas characteristics available
Safety devices as listed on the top of this bulletin. Automatic pre-ignition purge
period and push button electric ignition contributes to ease of operation. Modulating
gas burners fire from opposing sides to circulate heated air through the 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 top opening for easy loading. In the
closed position, full door weight seats door firmly against furnace top plate.
Structural steel pivot arms supported on furnace top plate by rugged pillow blocks
connected to a heavy duty electromechanical actuator. The door is controlled by
a switch at the furnace control panel.
AIR DOOR
Door pivots upward above furnace, clearing top opening for easy loading. In the
closed position, full door weight seats door firmly against furnace top plate.
Structural steel pivot arms supported on furnace top plate by rugged pillow blocks
are connected to a large diameter air cylinder. 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
Inert Atmosphere Construction,
available on electric furnaces only, includes continuously welded furnace
shell, inert atmosphere gas inlet and outlet, sealed terminal boxes, high
temperature door gasket Option IAC
Inert Atmosphere Inlet Piping,
with indicating flow control and manual gas valve. Specify atmosphere Option IAIP
High Temperature Construction,
2200°F maximum operation temperature, 9" thick insulation Option HTC
UL
LISTED CONTROL PANEL
