Patent ID: 8728408

Claim:
A nozzle assembly for mounting in a mechanical or an electronic pipette comprising: a two-piece body consisting of a nozzle ( 3 ) and a holder ( 2 ); a plunger ( 1 ) cooperating via engaging means with a pipetting rod ( 18 ) of a drawing up and discharging mechanism of the pipette, the drawing up and discharging mechanism being placed in a handle ( 16 ) of the pipette; and sealing means for sealing the plunger ( 1 ) in the nozzle assembly; wherein the nozzle ( 3 ) is in its lower part shaped respectively for receiving a pipette exchangeable tip ( 19 ) and is in its upper part releasably connected with the holder ( 2 ); characterized in that in the holder ( 2 ) the nozzle assembly has a pressure sleeve ( 6 ) slidably borne in the holder ( 2 ), which by a pressure sub-assembly seated in the holder ( 2 ) is pressed to the sealing means placed between the pressure sleeve ( 6 ) and the nozzle ( 3 ), wherein the plunger ( 1 ) is slidably borne in the pressure sleeve ( 6 ) and in the pressure sub-assembly, for ensuring leakproofness of the plunger ( 1 ) in the nozzle ( 3 ) in PIPETTING, ADJUSTMENT or CALIBRATION MODES of the pipette, wherein after releasing the nozzle ( 3 ) from the holder ( 2 ) in order to perform maintenance service of the pipette, the sealing means slide out automatically from an abutting surface ( 2 c ) of the holder ( 2 ) and remain located on the plunger ( 1 ), for facilitating the access to the sealing means in MAINTENANCE MODE of the pipette.