On Wed, 26 Dec 2012 21:11:03 +0000, ss <
wee...@hotmail.com> enthralled us
all with:
I think you would get more negative air pressure by sucking air out of
the cartridge with a syringe than using a big plastic bag and a 'vacuum'
cleaner.
I think you only need to reduce the air pressure in the big plastic bags
by a very small amount for them to be compressed by atmospheric pressure
- you are probably mainly removing excess air rather than creating much
of a vacuum.
Perhaps you might be better off with a small vacuum pump and a bell jar
or demijohn where you can route your tubing through the stopper and keep
a small reduction in air pressure inside the jar which should be all you
need to remove air from the cartridge.
Mind you it is a long time since I did 'A' Level Physics when they gave
you this kind of toy to play with :-)
I am wondering, though, why they need a vacuum fill?
Presumably previous cartridges had some kind of two way breather so that
air could be vented when ink was added under pressure, and air could
enter as the ink was used up.
Speculating wildly, this might encourage evaporation and the cartridge
drying up.
So they may have introduced some kind of valve or membrane to prevent
this.
I still wonder why a vacuum, though.
If the internal pressure of the ink is higher than the outside air
pressure then air should flow out of the cartridge. Reducing the external
air pressure may speed this process but ink should still flow in and air
should still flow out as long as there is ink pressure from the syringe.
Cheers
Dave R
--
PAN from within Ubuntu within VMWare.