Of course, you are quite correct - put it down to a 'senior' moment (slaps wrist .. lol); I meant to say that the 'quantity' of air in the water remained the same.
The term 'saturated' is rather nebulous though; the volume of air in water depends, as you rightly said, on Henry's Law - and Henry's Law gives a maximum of 22litres of dissolved air per m3 of water (at 1Bar(g) and 10'C) - but surely this is at the point of maximum humidity where air cannot hold more moisture and thus the water vapour pressure is as high as it will go. The standard water vapour pressure within the atmosphere is generally much lower and thus the quantity of air able to be dissolved in the tank water. The essence of my argument has to remain - although I rather wish that I remembered enough to be able to add 'time' into the equation more precisely. Trevor Martin P. wrote ... On Sat, 2009-01-17 at 13:39 +0000, Trevor wrote: > The fresh water in the tank is no more, or no less, 'saturated' with air > than the water in the pipes (why should it be different - unless it was > passed through a de-aerator along the way? The water in the tank will be roughly saturated with air at atmospheric pressure. Pump that water in the pipes downstream of the pump to a notional 2 bar(g) and it will be only 1/3 saturated. Remember Henry's law?
