Brooks Instrument GF126 - Manual (Page 25)

2-5
GF100 Series
Installation and Operation Manual
X-TMF-GF100-Series-MFC-eng
Part Number: 541B137AAG
March, 2013 Section 2 Installation
2-11 Purge the Gas Supply Line Before GF100 Series Installation
Before operating the GF100 Series, the gas supply line must be completely
purged with nitrogen or argon to ensure the line is free from toxic or
flammable gases, contaminants, moisture, and oxygen. The purge gas must
be free of moisture and oxygen to less than 100 ppb. Purge the gas lines as
follows or in accordance to prescribed company and safety procedures.
1. Shut off the process gas supply valve(s) upstream of the GF100 Series.
If such a valve is not available, shut the valve on the gas panel. Tag the
valve at this point to prevent accidental re-exposure of the process gas
to the gas line.
2. Cycle purge the gas line with dry nitrogen or argon to fully flush out the
process gas. Cycle purging consists of evacuating to a low pressure
adequate to induce out-gassing and then purging to remove adhered
moisture and oxygen. If a toxic or reactive gas is present and a clogged
GF100 Series is suspected, then proceed with caution. Pump down and
purge the GF100 Series from both downstream and upstream lines. If
check valves are present in the gas line, both pumping down and
purging are required. Pumping down without purging is inadequate. If a
good vacuum source is not available, the GF100 Series can be de-
contaminated by purge only.
3. Repeat the purge cycle several times within 2-4 hours to complete the
cleaning. For toxic and corrosive gasses, it is recommended to use 100-
120 cycles.