Here is the situation: We are building a small model car (roughly 8 in wide by 18 in long) whereby hydrogen is produced in a chemical reaction, travels through some tubing to our fuel cells, which in turn powers the motor. The issue lies in the start-up procedure; it is required to purge air from the tubing system so as to not dilute the hydrogen within the system. Here is how we are purging the system currently: We begin the reaction, producing hydrogen gas which removes any air present in the tubing, venting to the environment. After the short purge period, the outlets are closed off, and the car proceeds. The problem is, we require no hydrogen emissions to the environment during the purge. Is there any way to accomplish this? Thank you. P.S., please let me know if this description is unclear, I can provide diagrams and/or pictures as required.