By {HEAD ~ variation} of the liquid as well as by alteration of {TAIL ~ the porosity} of the carrier the opening pressure of the valve can be varied 
By { HEAD ~ variation } of the liquid as well as by alteration of { TAIL ~ the porosity } of the carrier the opening pressure of the valve can be varied
OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH