Patent ID: 8544682

Claim:
A device for the serial ejection of at least two fluid components comprising a) a barrel ( 1 ), having a longitudinal axis, having a front with an outlet or preparation for an outlet ( 13 ), b) a movable front piston ( 7 ) in the barrel defining a front chamber ( 3 ) between the front piston ( 7 ) and the barrel front, c) a movable rear piston ( 17 ) defining a rear chamber ( 5 ) between the rear piston ( 17 ) and the front piston ( 7 ), d) a rear bypass arrangement ( 9 ) allowing fluid transfer from the rear chamber ( 5 ) to the front chamber ( 3 ) and e) a front bypass arrangement ( 11 ) allowing fluid transfer past (or through) the front piston to the outlet ( 13 ), characterized in that the device further comprises a spacer ( 19 - 19 f ) being arranged to change shape between at least two states, i) a first state allowing the front piston ( 7 ) to be displaced forwards by action on the rear piston ( 17 ) while a fluid volume is retained in the rear chamber ( 5 ) and ii) a second state allowing the rear chamber to volumetrically shrink while fluid is transferred past (or through) the front piston thereby enabling the use of a liquid, initially provided in the rear chamber, for the dual purposes of mixing and rinsing.