Revision 5
11
August 2021
wear) suitable for high temperature work. This applies even if the Tail Gas Line (Process Stream)
is believed to be at negative pressure.
During normal operation, toxic gases, (H
2
S, SO
2
, COS and CS
2
) are present in the tubing,
measurement cell, aspirator and all other system components through which the tail gas sample
flows. They should not be opened before the complete system is purged with zero gas (an inert
gas or instrument air), and the system is blocked using the two valves in the sample oven identified
as the
Sample Flow
and
Vent Flow
on/off valves.
Purging of the system should be performed with both valves in the open position and maintained
for approximately five (5) minutes. Once purging is complete, and with the purge gas still flowing,
the two valves should be switched to the
Off
position. The purge gas can now be shut off and the
tubing or associated apparatus opened.
The sampling system will be under positive pressure. Loosen a fitting and allow the pressure to be
released before completely disconnecting the tubing.
The entire system is enclosed in an oven cabinet that is heated and maintained at approximately
150ºC/300ºF to prevent the condensation of sulfur. Maintenance performed before the cooling of
the oven and hardware should be done while wearing suitable protective clothing, eye wear, and
gloves to prevent burns to the hands and arms.
The system includes an Ultraviolet spectrometer which employs a source that generates intense
UV radiation that is transmitted to the measurement cell and spectrometer through fibre optic
cables.
This radiation is extremely harmful to the naked eye and skin, even in short duration exposures.
Always extinguish the UV radiation source (lamp) before removing a fibre optic cable or the lamp
power supply cover by turning the AC power to the lamp power supply ‘Off’. Should the lamp be
turned on for any reason while the cover is off, ensure that certified eye protection is worn, and that
the exposure is limited to the bare minimum.
Although the UV radiation is transmitted through a narrow diameter fibre, it should never be viewed
directly. The beam is extremely intense and will cause permanent eye damage. Should visual
inspection of the beam be required, point the end of the fibre at an inanimate object and view the
illumination reflection. Never expose human skin to the radiation from the optical fibres.
943-TGXeNA (CSA)
Class I, Division 2, Groups C and D, Temperature Code T3, Type Z Purge
IP Protection:
NEMA 4
Ambient Temperature:
-20°C to 50°C
The control cabinet purge gas is to be instrument air only.
Содержание 943-TGXeNA
Страница 130: ...Revision 5 130 August 2021 Figure 82 Oven Cabinet Door Removed ...
Страница 131: ...Revision 5 131 August 2021 Figure 83 Control Cabinet Door Removed ...
Страница 132: ...Revision 5 132 August 2021 Figure 84 Power Steam Air Signals Connection Details ...
Страница 133: ...Revision 5 133 August 2021 Figure 85 AC Wiring Schematic ...
Страница 134: ...Revision 5 134 August 2021 Figure 86 DC Signals and Wiring Diagram ...
Страница 135: ...Revision 5 135 August 2021 Figure 87 Flow Diagram ...