one-way air intake ducting in negative air pressure room?

[idea]

i am thinking of tweaking my small room and i need some hvac help. this is hard to describe but i will give it a shot.

i have a room that uses an inline fan as an exhaust, so the room has negative air pressure overall. the room's exhaust fan, which is an inline fan, creates negative air pressure in the room, which draws in fresh air from an adjacent room through a small hole in the wall. here is the current airflow.

adjacent room -> room -> carbon filter -> inline fan -> back to adjacent room

room temps run a little high but not too high for my purposes.

i would like to get some fresh cool outside air into the room, but i am very paranoid about smell leackage. the room has some unused ducting that leads to the outside, so i could just unplug this ducting and air should be drawn into the room from the inline fan's pressure if i plug the current intake hole, right?

now i would like to use some kind of one-way air ducting so that if the inline fan stops drawing air for some reason, then there would be no air leakage through the duct that leads outside. so it would run like this.

outside air -> [via one-way duct] -> room -> carbon filter -> inline fan -> adjacent room

is there some way to make an air duct run only one way? if the outside air duct is operating 24/7 is there some way to disquise it? i am not too worried about this because the air draw would be pretty weak because this light/room setup is small, but i am looking to leave no external hint that something interesting is going on inside of the structure. thanks.

 

[wastekan]

you can get a 'duct damper' that only allows air to move in one direction. the following link 'splains what they are and how they work:
http://www.rewci.com/416splobada.html.

 

[Blunt_69]

You should be ok without a one way because you are still creating negative pressure. Wherby your pullin cool fresh air in through from the outside rather then the adjacent room.. Understand that you will now create positive pressure in the adjacent room, which may not be desirable, might not matter. As long as you are creating negative pressure in your room with the inline(24/7) you should be golden. If the fans turns off, leakage will occur.

 

[idea]

thanks for the info all.

do those backdraft dampers require much pressure to open? i guess i could heavily lubricate the mechanism or replace the spring if so.

 

[Aeroguerilla]

(if in your case the air duct is against any type of screen)ive always gone down to the hardware store and bought some really thick black screen, put it over the screen thats already on window, creates a nice cover, cant see anything, but u hear it!