Electrical
temperature measurement
Flame rod for pilot light detection
Model GFR-3
WIKA data sheet SP 05.17
Applications
■■ Crude furnaces
■■ Fluid catalytic cracking furnaces
■■ Hydrotreater furnaces
■■ Hydrocracking furnaces
Special features
■■ Designed for the rigors of higher preheat furnaces
(482 °C / 900 °F)
■■ Significantly more robust design and materials for higher
reliability
■■ Improved tip design to facilitate easier Kanthal tip
replacement
■■ Simple maintenance
Flame rod, model GFR-3
Description
The model GFR-3 is the newest generation flame rod for
pilot light detection. It detects the actual flame present at
the pilot. This allows the operator to be sure the pilot is lit
before charging fuel to the burner. Flame rods are designed
to simplify pilot light detection systems by creating a one
piece instrument that allows for relatively easy access in
changing the Kanthal tip. The GFR-3 is designed in response
to ever more demanding furnace service requirements of our
customers.
WIKA data sheet SP 05.17 ∙ 04/2015
Data sheets showing similar products:
Flame rod Kanthal tip; model KNTH; see data sheet SP 05.18
This design allows for discrete pilot flame indication and
eliminates the non-discrete indication of optical scanners.
It is suitable for pilots designed by Callidus, John Zink, and
Zeeco and is the standard for major refineries as part of safe
furnace operation programs.
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Design principle
The flame rod is positioned such that the high-temperature
sensing rod would be in contact with the pilot flame. The
flame creates an ionized “path” between the centre electrode/
rod and the electrical ground. The excitation voltage induces
a current flow across this “path”. This current is a stable and
measurable signal which can then be used in the appropriate
control scheme.
Instrument requirements
The electrical instrument requirements consist of an
excitation voltage (AC 80 ... 240 V, single phase) applied
across the two flexible extension leads and current sensing
ability. In addition, relays and time delay capabilities are used
to control the sequence between pilot and burner.
Construction
The flame rod consists of a center electrode and an outer
metallic sheath. The electrode is isolated from the outer
sheath by an insulating material. The end of the flame rod, in
the flame path, has a special high-temperature hermetic seal
with a threaded adapter which is connected to the centre
electrode.
A Kanthal tip is attached to the threaded adapter.
The opposite end of the flame rod, outside the furnace/boiler,
has flexible extension leads which connect to the centre
electrode and the outer sheath.
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WIKA data sheet SP 05.17 ∙ 04/2015
Ordering information
Callidus style flame rod
Order code:
GFR - 3 -
“L”-Dimension
-C
“L”-Dimension is from the “etch” mark to the bottom of the insulator cap assembly. This is 359 mm (14 1/8") short of the full
length of the assembly minus the hex adapter and Kanthal tip.
305 mm (12") min.
54 mm
(2 1/8")
L
(Callidus design)
Compression fitting
Ø 1/2" tube x 1/2 NPT
John zink style flame rod
Order code:
GFR - 3 -
“L”-Dimension
- JZ
“L”-Dimension is from the end of the flame rod to the threaded tip on the end of the insulator cap assembly.
Ensure that the last 178 mm (7") of the flame rod before the connection head remain in an area that is cooler than
90 °C (194 °F). The seal in this area is not designed for higher temperatures.
178 mm (7") min.
< 90 °C (194 °F)
L
(John Zink design)
Compression fitting
Ø 1/2" tube x 1/2 NPT
04/2015 EN
© 2015 WIKA Alexander Wiegand SE & Co. KG, all rights reserved.
The specifications given in this document represent the state of engineering at the time of publishing.
We reserve the right to make modifications to the specifications and materials.
WIKA data sheet SP 05.17 ∙ 04/2015
Page 3 of 3
WIKA Alexander Wiegand SE & Co. KG
Alexander-Wiegand-Straße 30
63911 Klingenberg/Germany
Tel.
+49 9372 132-0
Fax
+49 9372 132-406
info@wika.de
www.wika.de