Atmospheric Technology
5
2.1.2.4
Mass Flow Controllers
A mass flow controller with a nominal range of 0-10 cc/min is used to control the
sampling flowrate in each canister. If the optional collocated Channel 2 and Channel
3 are present, each channel would have a dedicated mass flow controller usually in
the 0-10 cc/min range. The sampling flow rate is automatically calculated using the
starting and end pressure and the sample duration. Operation and maintenance
instructions for the mass flow controller are provided in Appendix B.
2.1.2.5
Purge Pump
A diaphragm pump is used to purge the sampler inlet line by drawing air through the
inlet tubing, mass flow controller, and 3-way isolation solenoid valve and exhausted
out. A check valve isolates the exhaust path from the rest of the system. For
pressurized sampling, a pressure pump pushes air through the components. The
duration of purging prior to sampling can be specified in the Setup screen.
