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SAMPLE HANDLING |
AIR MONITORING
Canister Maintenance/Recondi t ioning
Sampling Kit/Flow Controller Repair
Includes all new rubber seals in flow controller and orifice and frit replacement
cat.# 550131
Canister Repair
Includes valve replacement, leak test & cleaning
cat.# 560838
Normal wear and tear on canisters and components can result in
damage causing leakage. Restek’s repair service allows you to extend
the life of your equipment for much less than the cost to replace with
new products. Contact Customer Service at 800-356-1688, or your
Restek representative, to take advantage of this service. You will be
given instructions and an SRV # to return the parts to us.
Canister and Flow Controller Repair Service
Save money and increase performance with Restek’s canister and flow controller repair service.
How to Extend Canister Life
What reduces canister performance and longevity? Leakage is the most common reason for canister failure, but contamination
and damage to the fused silica lining can also send canisters to the scrap yard prematurely. Here are some tips to protect your
investment:
1. Prevent leaks
Use proper handling to avoid these 3 leading causes of leaks.
a. Particles in the valve
You can prevent particles from entering the valve by always using a 2 or 7 µm particulate filter during sampling and on
your canister cleaning equipment. Also, protect the valve inlet by replacing the brass dust cap when not in use. The EPA-
recommended metal-to-metal sealing valves provide the greatest inertness, but tend to be more sensitive to particulate
damage than other valve types.
b. Galled thread fittings
Avoid galled thread fittings by using a gap gauge to prevent overtightening of compression fittings. Turning only ¼ turn
past finger-tight is another rule of thumb to prevent overtightening. Use brass compression fittings on stainless steel,
during nonsampling activities, such as cleaning or calibration, to minimize thread damage. Galled threads may also cause
a poor connection to vacuum/pressure gauges, resulting in inaccurate measurement and misleading conclusion that
canister leakage exists.
c. Overtightened valve
Canister valves are designed to close securely with hand tightening only. Overtightening a valve closure with a wrench
may damage the valve seat where the seal is made.
2. Reduce contamination
a. Segregate high concentration (ppm) cans and trace concentration (ppb) cans. Use dedicated canisters, or gas sampling
bags, for ppm level sampling, since it is extremely difficult to remove impurities from ppm sampling to a level suitable for
trace sampling.
b. Clean the entire sampling train as you would the can to minimize introduction of contaminants into a clean can.
Maximum temperature is 80 °C on the gauge and 90 °C on Restek’s Veriflo® flow controller.
c. High temperature (>100 °C) humidified air (steam cleaning) provides the most effective way to remove contamination
from electropolished cans (TO-Can® or SUMMA® canisters), but can damage fused silica lined cans. See #3 below for
proper cleaning of fused silica lined cans.
3. Avoid damage to fused silica lined cans
Be sure to followmethod recommendations when cleaning your canisters to avoid damaging the fused silica lining. Cleaning
studies of SilcoCan® canisters using humidified air and heat at 80 °C and 125 °C have shown reduced recoveries of sulfur
compounds, when compared to using nitrogen under the same conditions. This irreversible damage is due to oxidation of
the surface, creating active sites that may affect the recovery of reactive or polar compounds. Strong acids and bases may
also result in damage to the internal can surface.
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E-mail :
TelNo : 03 9762 2034 . . . in AUSTRALIA
Mar 2011
