An electric valve comprising: a valve body , the valve body housing: a nut having a central shaft ; a screw threadingly engaged within said nut , the screw having a screw axis; at least one projection attached at a periphery of said nut ; and a limiter positioned in an inner side of said valve body and configured so that said at least one projection is abuttable therewith; wherein said nut moves together with said screw until said at least one projection reaches and abuts against said limiter ; characterized in that the valve further comprises: a seal mounted to said central shaft and configured to move freely with respect to the central shaft , both axially and rotatably there-about; sliding bearings disposed between said nut and said seal and disposed between said nut and a base of said screw ; and a lip correspondingly disposed with respect to said seal and reversibly engagable therewith; whereby, due to the slide bearings , neither upon opening of the valve nor upon closing of the valve does the seal slide on the lip . a valve body , the valve body housing: a nut having a central shaft ; a screw threadingly engaged within said nut , the screw having a screw axis; at least one projection attached at a periphery of said nut ; and a limiter positioned in an inner side of said valve body and configured so that said at least one projection is abuttable therewith; wherein said nut moves together with said screw until said at least one projection reaches and abuts against said limiter ; characterized in that the valve further comprises: a seal mounted to said central shaft and configured to move freely with respect to the central shaft , both axially and rotatably there-about; sliding bearings disposed between said nut and said seal and disposed between said nut and a base of said screw ; and a lip correspondingly disposed with respect to said seal and reversibly engagable therewith; whereby, due to the slide bearings , neither upon opening of the valve nor upon closing of the valve does the seal slide on the lip . a nut having a central shaft ; a screw threadingly engaged within said nut , the screw having a screw axis; at least one projection attached at a periphery of said nut ; and a limiter positioned in an inner side of said valve body and configured so that said at least one projection is abuttable therewith; wherein said nut moves together with said screw until said at least one projection reaches and abuts against said limiter ; characterized in that the valve further comprises: a seal mounted to said central shaft and configured to move freely with respect to the central shaft , both axially and rotatably there-about; sliding bearings disposed between said nut and said seal and disposed between said nut and a base of said screw ; and a lip correspondingly disposed with respect to said seal and reversibly engagable therewith; whereby, due to the slide bearings , neither upon opening of the valve nor upon closing of the valve does the seal slide on the lip . a seal mounted to said central shaft and configured to move freely with respect to the central shaft , both axially and rotatably there-about; sliding bearings disposed between said nut and said seal and disposed between said nut and a base of said screw ; and a lip correspondingly disposed with respect to said seal and reversibly engagable therewith; whereby, due to the slide bearings , neither upon opening of the valve nor upon closing of the valve does the seal slide on the lip . <EOS>