| 摘要 |
A pipetting and dosing device, in particular for use in automatic clinical analysis apparatuses, for dosing and dispensing accurate liquid volumes, such as samples and reagents, comprises an internally cylindrical suction pipe (5) with a conically tapering distal end (17) with a central opening (18), a piston (7) axially movable within the suction pipe while sealing against the inner wall of the pipe, and drive means (8-13) for moving the piston axially over well-defined distances in the suction pipe for, respectively, sucking up and discharging predeterminable volumes of liquid. The end of the piston facing the conically tapering distal end (17) of the suction pipe (5) is provided with a conical tip (7a) having an apex angle of the conically tapering end of the suction pipe and this conical piston tip (7a), or alternatively the conically tapering end (17) of the suction pipe, is made of a resiliently deformable material. At the end of the discharge movement of the piston in the suction pipe the conical tip (7a) of the piston is moved into abutment against the conically tapering end (17) of the suction pipe with such an axial force that, through elastic deformation of the piston tip or alternatively the conically tapering end of the suction pipe, the piston tip and the conically tapering end of the suction pipe are brought into complete conformity without any residual interspace remaining therebetween. |
