Does Capillary Diameter Affect Flow Rate Stability in a Decreasing Vacuum?

[taggart]

we vacate a cannister using a vacuum pump using a range from 200-900 mbar of vaccum. Will the flow rate remain constant as the vacuum decreases over 24 hrs or does it tail off at a given pressure, a capillary of diameter 0.102mm is used ?

 

[Andy Resnick]

http://www.engineeringtoolbox.com/vacuum-evacuation-time-d_844.html

Re-arranging the expression shows the pressure in your cannister decreases exponentially.

Does that help?