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GF SERIES


SILICON CARBIDE ELEMENT ELECTRIC FLOOR STANDING BOX FURNACES 2800°F (1535°C)

The GF SERIES Electric Furnaces feature 2800°F (1535°C) operation. Silicon carbide elements are controlled with a phase angle fired SCR. The door features a deep plug for minimal heat loss around the door. Because this door must be opened horizontally the furnace can not be loaded and unloaded easily at high temperatures. These furnaces are excellent for long high temperature cycles. They are used mostly in ceramics but find application in chemical processing and other fields.

FEATURES

SILICON CARBIDE HEATING ELEMENTS
Silicon carbide heating elements are mounted over and under the hearth for even heating. All element connections are on the sides. Watt density is between 30 and 39. Elements are rated for 3000F (1650C).

FLOOR STANDING CASE CONSTRUCTION
The case is reinforced 10 gauge and 3/16” sheet steel with an integrated floor stand and lifting rings. The entire case is primed with 800F silicone paint and finished in machine enamel.

MULTILAYERED INSULATION; CERAMIC FIBER ROOF AND DOOR PLUG
There is 4-1/2” of 3000F (1650C) insulating firebrick backed up with 4” of 2300F (1260C) ceramic fiber. The roof and door are made from 2850F (1565C) ceramic fiber modules. All insulation is available in preshaped sections for easy maintenance. As an option the entire insulation can be ceramic fiber modules for fast heat up and cool down. No asbestos is used.

DEEP PLUG DOOR WITH VESTIBULE AND DOUBLE PIVOT HINGE FOR EXTREMELY TIGHT SEAL
The horizontally opening door features a 2” deep plug for excellent heat blockage even at elevated temperatures. Double pivoting of hinge allows parallelogram opening of the plug door. This keeps the hot face from the operator and allows tight sealing of the door. A vestibule around the perimeter of the door reduces heat loss when the door is opened. This also aids temperature uniformity while protecting the elements from physical damage.

TEMPERATURE UNIFORMITY OF +/-25F (+/-15C)
Uniformity of +/-25F (+/-15C) is normal above 1600F (870C) within 2/3 of the working dimensions.

1-1/2” THICK SILICON CARBIDE HEARTH
The hearth is a 1-1/2” thick silicon carbide hearth plate for strength and excellent heat transfer. Height from floor to hearth is 32”.

DIGITAL PID CONTROL AND HIGH LIMIT SYSTEM
The standard control is a Honeywell UDC 2000 digital PID 3 mode tuning control. All fuses, contactors, and controls are located in a NEMA 1 panel. The thermocouples are Type R. The control voltage is transformed to 120 volts. A NEMA 13 Lighted On/Off switch and NEMA 13 door power cut off switch are included. A Honeywell UDC 2000 digital high limit back up control with manual reset, back up contactors and separate thermocouple is standard. Customer must connect fused power supply to single point on panel .

SCR POWER CONTROL AND TAP TRANSFORMER
The power control has a 6 position tap transformer with taps that are changed inside the control panel and a phase angle fired SCR. The SCR adjusts for most voltage changes automatically as needed, eliminating the need to manually change taps during operation.

TESTING AND INSTRUCTIONS
The furnace is tested to insure circuit integrity. 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 and thermocouples (warranted for 6 months.)


OPTIONS


  • JIC CONTROL OPTION: This includes a NEMA 12 control cabinet, all oil tight switches and a panel mounted fused disconnect switch.
  • INERT ATMOSPHERE CONTROL: The GF furnaces can be fitted for use with inert or combustible atmospheres. Inlet of the atmosphere is through the element connection chamber to maintain cool element connections. This system includes special all aluminum element hardware inside the sealed boxes. The door features a special tadpole gasket. A completely piped flowmeter and regulator with ball valve, pressure gauge and pressure relief valve is included. Complete safety systems for use with combustible atmospheres are available. Temperature is limited to 2500F (1370C) with nitrogen, to 2200F (1200C) with any hydrogen over 4% but can take the full rated temperature with argon.
  • HIGH DENSITY ELEMENTS: These will provide greater element life than the standard silicon carbide elements, especially in atmosphere applications.
  • CONTROL, RECORDER AND ELECTRICAL OPTIONS
  • VENTURI VENT: A venturi can be provided for venting or quick cool down. This can be programmable.
  • COUNTERBALANCED VERTICAL DOORS: Manual hank crank, pneumatic or electric operation.

SPECIFICATIONS

MODEL
WORKING DIMENSIONS
INSIDE DIMENSIONS
OUTSIDE DIMENSIONS
K.W.
MAX LOAD
SHIP WEIGHT
NUMBER
W
H
D
IW
IH
ID
OW
OH
OD
 
LBS
LBS
GF 9
12
8
10
14
15-1/2
11-1/2
36
62
28
10
50
1400
GF 29
12
8
20
14
15-1/2
21-1/2
36
62
38
20
100
1800
GF 39
12
8
30
14
15-1/2
31-1/2
36
62
48
30
150
2200
GF 524
15
15
24
17
26-1/2
26
70
61
54
33
125
2000
GF 814
18
12
24
20
23-1/2
26
73
58
54
34
150
2200
GF 824
18
18
24
20
29-1/2
26
73
64
54
41
150
2700
GF 836
18
18
36
20
29-1/2
38
73
64
66
52
225
3400
GF 236
24
18
36
26
29-1/2
38
79
64
66
60
300
4100
GF 244
24
24
24
26
35-1/2
26
79
70
54
54
200
3900
GF 246
24
24
36
26
35-1/2
38
79
70
66
66
300
4300
GF 248
24
24
48
26
35-1/2
50
79
70
78
86
400
5900
GF 3636
36
36
36
38
47-1/2
38
91
82
66
106
450
7400
GF 3648
36
36
48
38
47-1/2
50
91
82
78
127
600
8600
GF 3672
36
36
72
38
47-1/2
74
91
82
102
164
900
10000
All dimensions are in inches. Weight is in pounds. Typical floor standing control panel is 24” wide by 66” high by 36” deep. 240 or 460 volts is normal. 208, 380 and 575 volts are optional. Three phase is normal, although single phase is available. All circuits are balanced loads. Larger sizes are available by special quote. Specifications are subject to change without notice.

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