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