koma said:
I don't think it is a pilot type since it is specified for operation
from 0 bar.
A pilot type needs some pressure to actually keep the valve closed,
right?
It is a spring return on this one.
I just don't understand how it can be specified for gas and not work
with for example water?
If it is airtight it should be watertight as well?
(For a non-pilot type valve that is...)
No, not very well. There is this issue of density, gasses at 22 L/mole vs
water at 18 mL/mole.
Then there is also the issue of viscosity, it involves how much flow you can
get through a given size hole. You can get more mass per unit time of a gas
through a given size hole than you can get of any liquid; in spite of the
1000:1 density difference.