Patent EP-1875966-A1 (EP)
Inventor: WILMER JENS
IPC: B01L3/02
Filed: 2007-06-05
Abstract: The multi-channel pipetting device for dosing of liquids, comprises a piston control rod (9), a reception arranged at an end of the rod for piston head that is limited in axial direction from a contact surface (20) for the piston head, a cylinder with a cavity, a seat for holding a pipette tip, and a passage opening for a plastic piston rod. The passage opening surrounds a base for supporting the piston head. A passage channel is connected to the cavity of the cylinder with a clearance hole (31) in a seat. The piston is arranged longitudinally relocatable in the cavity of cylinder. The multi-channel pipetting device for dosing of liquids, comprises a piston control rod (9), a reception arranged at an end of the rod for piston head that is limited in axial direction from a contact surface (20) for the piston head, a cylinder with a cavity, a seat for holding a pipette tip, and a passage opening for a plastic piston rod. The passage opening surrounds a base for supporting the piston head. A passage channel is connected to the cavity of the cylinder with a clearance hole (31) in a seat. The piston is arranged longitudinally relocatable in the cavity of cylinder. The piston rod extends through the passage opening of the reception and the piston head is arranged at the end of the piston rod, which is mount on the base with lower side faced towards the piston rod and which has flexible body out-standing over the top side turned away from the piston rod. The flexible body does not rest or partly flexibly squeezed together against the contact surface. The piston control rod has a cross beam aligned transverse to its longitudinal axis. The piston control rod has several reception arranged next to each other and is arranged with its piston head in the reception. The reception has an insert opening extended diagonally to the piston control rod for the piston head and the piston rod. The piston head with a ring plate is supported on the base and has a cone between ring plate and piston rod. The piston at the top side of the piston head has a blind hole, in which the flexible body is partly arranged. The blind hole has an extension in a distance of its opening and the flexible body intervenes in the extension. The blind hole has diametrically extensions facing each other. The extensions proceed from a recess at the base of the blind hole. The flexible body has a spherical section, which protrudes from the piston head. The piston has a cone at the end removed from the piston head and the cylinder and/or the connection channel has corresponding interior conicity. The plastic piston has a circulating piston seal at the end removed from the piston head. The piston seal is a piston sealing ring inserted in an annular groove at the extent of the piston. The flexible body is molded at the piston. The piston and the flexible body are manufactured in the multi-component injection molding process. The piston control rod protrudes from the side of the housing. An end of the piston control rod on a side of the housing is accessible from the outside. The housing has a fastening device (5) for fastening the pipetting device to a driving device.