Not a bad idea, Ben.  They would slow down the opening a bit, but would probably slow down the closing even more.  I'll check into it.

 

Ed

Assemble a swing check valve in parallel with your restrictor. So, most of the up flow is unrestricted and any downflow closes the check valve and goes through the restrictor.

Or machine the whole thing in a small block of aluminum.

 

Lynn E. Hanover