Greetings to all... :-)

Does anyone know a clear definition of "number of tube passes" in a fin-and-tube heat exchanger? Does it only depends on how many times the tube are bent? Please help...
| | | |
in ->-|---|---|---|---|
| | | | | tube turn
out -<-|---|---|---|---|
| | | |
fin fin fin fin

For two cases: 1) the air is blowing upward
2) the air is blowing into the screen

Is the number of tube passes the same or different?

Thank you very much!! Really confused here...

Best regards,
Lily