Does such a valve exist? (water check valve)

[Timscmitt]

Hi folks,

I am looking to solve a small issue.

It requires a 'valve' that will permit water travel in one direction whilst under low active pressure but which closes upon cessation of said pressure. Fair enough....but when closed I would like it to allow air into the system (downstream of the 'check valve') in such a way that when livened again water cannot escape through the 'venting arrangement.' So when live the valve is open but closed to the environment. When not live the valve closes and 'vents' the downstream aspect to the environment thus ensuring quick natural emptying of that pipe. The distance from the 'valve' to terminal pipe fitting is 100mm .

So its a kind of check valve/air admittance valve all in one and in 1/2".

Any help with this little quest would be most appreciated.

Have a great weekend!!

 

[Lnewqban]

Welcome, @Timscmitt !

Would something like this work?:

https://en.wikipedia.org/wiki/Atmospheric_vacuum_breaker

 

[berkeman]

Could you upload a sketch to help clarify the system? Use the "Attach files" link below the Edit window to upload a PDF or JPEG version of your sketch. Thanks.