device to let air out but not water under pressure

My research project needs a device which can let air escape but not the water under about 3000psi pressure. I have a container with waters. But air may go in during filling process. The air is not allowed for a particular reason. After close the container, we will add pressure by pushing to about 3000psi. We need the air escapes from the container during this process but not the water. Temperature is room temperature.

Does this device exist? any name/link will be appreciated.
thanks,

Type bleed valve or purge valve in your search engine.

Not knowing the scale you are dealing with, nor whether a small amount of water is allowed to be purged in the process, I would suggest you look at a car's hydraulic breaking system. Been around for years and will only work correctly when the air has been bled out. :)

Dare I suggest that "My research project," has not had enough research done on it.