Quote: (Originally Posted by jradomski)
.. You will be surprised how little back pressure is needed to alter the calibration....
I have been obsessing over this for a while now. One method I tried (on the Meg) was to rubber band a plastic bag with a hole in it over the (bottom) outlet. I'd pinch the hole off while the O2 is flowing and when the bag fills I'd open the hole & flush the O2 through. I'd do this 2 or 3X & then just open the hole & let the gas flow until the mv's stabilize & then calibrate, the logic being that the bag would contain the O2 environment with little or no back pressure.
I intend to make a plug with a digital gauge & a bleed valve so I can pressurize to 1 ata and see if I get a 1.0 readout. I just don't see how a screw in the bottom of a brass fitting can give consistent, accurate lpm & zero back pressure unless the whole system is engineered to take into account the relationship between the inlet and the outlet.
Or am I just being neurotic about this whole thing.....?
