Looking after Gas-Tec
Gas-Tec
28
X Looking after Gas-Tec
10.1 Gas cylinder
Start with a filled gas cylinder . The ‘gas pressure low’ prompt will show when the pressure is too low for
the unit to function properly .
A full 400 ml gas cylinder (150 bar, 2150 psi) should last for approximately 60 hours . The average hourly
pressure drop is approximately 2 .5 bar (35 psi) .
Make sure the cylinder is turned off using the gas cylinder ON/OFF valve after each use .
See also Section XII Hydrogen Safety (p32)
10.2 Filters
The purpose of the filter assembly is to protect the flame chamber from contamination . If water or solid
particles enter the chamber, it may cease to function properly . The accuracy of readings may be affected .
The filter assembly consists of a filter backing disc, a 25 mm diameter hydrophobic filter element, an 'O'
ring, and a 27 mm diameter paper pre-filter element . Assemble the filter using components in order as
shown in the illustration below .
The paper pre-filter should be inspected regularly and replaced when necessary . This will protect the
hydrophobic filter from coarse contamination and extend its life . When fitting this filter, the hydrophobic
surface should be placed in contact the 'O' ring . The fibrous surface, marked with a red dot, should be
placed face down against the backing disc .
If water enters the filter assembly, the hydrophobic surface will prevent moisture entering the flame cham-
ber, but before continuing to use the Gas-Tec, make sure the probe and pre-filters are clear .
Discard the pre-filter .
Shake or blow lightly on the hydrophobic surface .
Reassemble the unit with a new pre-filter .
Dry and clean the probe and tube assemblies thoroughly before reusing .
NOTE: Instruments should not be run without the filter assembly .
10.3 Probes and tubes
Check probes and tubes for damage before use .
The water trap cavity at the bottom of the insulated probe handle
should be cleaned out with a clean rag or tissue (do not use volatile
solvents) . The joint should be opened periodically and any water
shaken out . Avoid water passing into the instrument .