Device 3, wherein the valve is contained with play between two grids mounted in {HEAD ~ series} with {TAIL ~ the port}, and wherein the overall mean diameter of the apertures of each grid is less than the mean diameter of the port 
with
Device 3 , wherein the valve is contained with play between two grids mounted in { HEAD ~ series } with { TAIL ~ the port } , and wherein the overall mean diameter of the apertures of each grid is less than the mean diameter of the port
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH