A pressure relief valve for {TAIL ~ packages} in which {HEAD ~ the valve element} comprises a liquid impregnated porous element covering outlet openings in the package, with the liquid layer in the porous element being torn open by package contents pressures in excess of a predetermined value to permit gas outflow from the package 
A pressure relief valve for { TAIL ~ packages } in which { HEAD ~ the valve element } comprises a liquid impregnated porous element covering outlet openings in the package , with the liquid layer in the porous element being torn open by package contents pressures in excess of a predetermined value to permit gas outflow from the package
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL REL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH