Abstract: A method for detaching a barrier means adapted to the end part of the suction device for closing an opening in the end part by the movement of a plunger intended for changing the volume of a cylindrical space provided in the end part whereby the barrier means is removed by bringing means for limiting the movement of the plunger in the cylindrical space, e.g. means intended for removing the disposable tip, in such a position that the plunger can be brought into contact with the barrier means for detaching the barrier means from the end part of the suction device.

Abstract: A pipette with adjustable volume, which pipette comprises a frame portion (1) shaped as a handle, a cylinder (2) being formed inside the said frame portion, as well as a piston (3) fitted into the cylinder by means of a seal ring (7), a piston rod (4) connected to the piston (3), as well as a press knob (5) with shaft (6), fitted at the upper end of the frame portion (1). By turning the said press knob (5), a sleeve (20), which determines the upper position of the piston (3) and which is non-rotable in relation to the frame portion (1) of the pipette, can be displaced, by means of a threaded joint (20), upwards or downwards relative the shaft (6) of the knob so as to adjust the volume of the pipette. The pipettable volume can be read numerically through an opening or window (40) in the pipette frame (1) by means of a series of rings consisting of numbered disc-shaped rings ( 31, 39).

Abstract: The subject of the invention is a pipette which comprises a frame portion (1) shaped as a handle, a cylinder being formed inside the frame portion (1), as well as a piston (5) fitted into the cylinder by means of a seal ring (7), a piston rod (4) connected to the piston (3), as well as a press knob (5) with shaft (6), fitted at the upper end of the frame portion (1). Around the shaft (6) of the press knob (5), a calibration sleeve (9) is fitted by means of a threaded joint (8), by means of which calibration sleeve (9) the lower limit of the movement of the piston (3) during pipetting can be determined. According to the invention, the calibration sleeve (9), as surrounded by the mantle (10) of the hollow press knob (5) and by the upper part of the pipette frame (1), is placed at a distance both from the mantle (10) of the press knob (5) and from the inner face of the cover of the upper part of the pipette frame (1).