▁the ▁equilibrium ▁state , ▁because ▁it ▁only ▁slightly ▁changes ▁the ▁CO 2 ▁partial ▁pressure ▁in ▁the ▁head space , ▁it ▁does ▁affect ▁the ▁k inet ics ▁of ▁how ▁that ▁equilibrium ▁state ▁is ▁reached . ▁ ▁The ▁increased ▁overall ▁pressure ▁slow s ▁down ▁the ▁rate ▁at ▁which ▁dissol ved ▁CO 2 ▁comes ▁out ▁of ▁solution . ▁ ▁For ▁a ▁few ▁hours ▁the ▁bott le ' s ▁contents ▁are ▁not ▁in ▁an ▁equilibrium ▁state . ▁ ▁The ▁application ▁of ▁the ▁F izz ▁K ee per ▁extends ▁this ▁period , ▁but ▁by ▁hours ▁not ▁by ▁days . ▁ ▁Ro hr ig ▁reports ▁that ▁this ▁can ▁be ▁and ▁has ▁been ▁easily ▁confirmed ▁by ▁experiment . ▁ ▁The ▁first ▁F izz ▁K ee per - like ▁device ▁was ▁pat ented ▁in ▁ 1 9 2 6 ▁by ▁G . ▁Sta un ton . ▁ ▁T . R . ▁Robinson ▁and ▁M . B . ▁Bey er ▁pat ented ▁the ▁F izz ▁K ee per ▁itself ▁in ▁ 1 9 8 8 , ▁without ▁claim ing ▁in ▁the ▁pat ent ▁that ▁the ▁device ▁maintained ▁a ▁soft ▁drink ' s ▁" f izz ". ▁ ▁Several ▁styles ▁of ▁device ▁exist , ▁from ▁the ▁plain ▁p ist on ▁p ump ▁to ▁devices ▁incorpor ating ▁a ▁bul b ▁and ▁a ▁l atch ▁and ▁h inge ▁device ▁to ▁allow ▁liquid ▁to ▁be ▁pou red ▁out ▁of ▁a ▁sp out ▁without ▁removing ▁the ▁F izz ▁K ee per ▁from ▁the ▁bott le . ▁ ▁Although ▁the ▁F izz ▁K ee per ▁does ▁not ▁operate