(57) The present invention solves the problem of working out a design of a plain pipette
which seves for drawing in, pipetting and dispensing the fluid of a strictly specified
volume and which is characterized by a high repeatability of results. The said pipette consists of a round casing /1/ being simultaneously a handle thereof, whereto, via a round nut /2/, there is fitted a multi-step shank /3/. Inside the body of casing /1/, there is a plunger /4/, being in the form of a multi-step rod,which is being displaced downwards with the
aid of a press means /16/ and of a round arbor /15/, contrary to the force being exerted by a lift-up spring /13/ which makes plunger /4/ return to its initial position. Furthermore, inside the body of casing /1/, centrally in the symmetry axis of the pipette, directly under press means /16/, there is a calibration unit comprising a multi-step calibration sleeve /19/, which is blocked from the top by a hold-down element /24/, being screwed into the body of casing /1/, inside whereof there freely slides an arbor /15/ being connected to press means /16/. The end of arbor /15/ is placed inside an elongated sleeve being a push rod /14/, which from the top rests with its flange upon the face of a stop /20/ being screwed into the internal thread of calibration sleeve /19/. From the top, upon the flange of push rod /14/, the pressure is being simultaneously exerted by a blow-out mechanism spring /22/, which from the top rests upon a washer /18/ being blocked by a ring /17/. The lower part of push rod /14/ gets in contact with a plunger's flange /10/, whereas between plunger's flange /10/ and the end of arbor /15/ there is a narrow slot /23/.
|

|