Attention:

Certain features of Sigma-Aldrich.com will be down for maintenance the evening of Friday August 18th starting at 8:00 pm CDT until Saturday August 19th at 12:01 pm CDT.   Please note that you still have telephone and email access to our local offices. We apologize for any inconvenience.

Gas Line Filter (remove dust and small particles)

Needle valves may become fouled by the presence of dust or particulate matter in a gas stream. To protect any component that has a needle valve incorporated, simply install a small, inexpensive gas line filter directly upstream.