Zavim, Chapter One, Mishnah Four
1) If he saw one [issue] and it stopped long enough for an immersion and a drying, and after that he saw two issues, or one as copious as two;
2) Or if he saw two [issues] or one as copious as two, and it stopped long enough for an immersion and a drying, and after that he again saw an issue, he is a full zav.
This mishnah deals with the question of how to determine if one discharge should be divided into two. In other words, how long must there be between discharges for them to count as two?
The answer in both of these cases is that if the flow stops long enough for him to have immersed and then dried off, the second flow is considered to be new.