TECHNICAL FORUMS > Digging
Draught testing challenge
(1/7) > >>
There are two caves a couple of kilometres apart. One draughts inwards in hot weather and the other (at lower level) draughts out. It would be useful to know if there is an air flow connection between the two caves.
Can anyone think of a way of labelling the inflowing air in such a way that it could be detected at the outwards draughting cave (in the manner of water tracing)?
Interesting post , I look forward to hearing some other people’s answers .
my Only idea would be to go in as far as possible and spray some extremely strong smelling stuff but this could obviously lead to breathing difficulties inside for the people in their ? Unless it was not harmful in anyway mmmm this is going to take some thinking :-\
Atmospheric pressure will certainly play a vital role in this test on a crystal clear day if you sprayed the chemical for example I imagine it would be sucked deep inside the cave system , on a extremely cloudy day it would more kick it back out in your face .
You will need to no the hole day is not going to change ie any clouds at all as a change in the pressure will turn the ventilation around and push the for example spray back out the same way ! Maybe a barometer might also help in this .
First thoughts are that if there is a large volume of air in between (which would be expected with a strong draught) anything you put in will be diluted within the cave and you're very unlikely to see anything at the outflow, whether or not they are connected.
Imagine using a hosepipe with red dye at one end of a swimming pool and an outfall at the other end. while switching on the hose would cause water to come out of the outfall almost immediately, you would need to put in a huge amount of dye over a long period before starting to see anything come out the other side.
Joss sticks - a bundle of something with a good strong scent should hopefully be detectable at the lower end if there is a connection? Smoke pellets would be another alternative for something visual.
There are some extremely strong substances about if you do some research. Also very small particles eg pollen might go through and could be captured
 Message Index
[#] Next page
Main MenuForum Home Help Search