Abstract: A device for aspirating and dispensing liquid samples comprising a pump that comprises a cylindrical chamber, a piston movable in this cylindrical chamber, and a piston drive that engages the piston. The device further comprises a tip connected to the cylindrical chamber with a line, and a channel system that discharges into the cylindrical chamber for flushing or rinsing the latter. The device is characterized in that the piston entirely seals this cylindrical chamber from the channel system, if the piston is positioned in the cylindrical chamber in such a way that a free piston end comes to rest between the channel system and the line. Preferably, the cylindrical chamber is located in a cylinder block, which comprises two parts that are separated by and enclosing an intermediate channel system. The channel system most preferably is implemented as a coherent cavity. According to a first embodiment, the cylindrical chamber is implemented as a sleeve that is inserted in a boring located in a cylinder block.

Abstract: A device for aspirating and dispensing liquid samples comprising a pump that comprises a cylindrical chamber, a piston movable in this cylindrical chamber, and a piston drive that engages the piston. The device further comprises a tip connected to the cylindrical chamber with a line, and a channel system that discharges into the cylindrical chamber for flushing or rinsing the latter. The device is characterized in that the piston entirely seals this cylindrical chamber from the channel system, if the piston is positioned in the cylindrical chamber in such a way that a free piston end comes to rest between the channel system and the line. Preferably, the cylindrical chamber is located in a cylinder block, which comprises two parts that are separated by and enclosing an intermediate channel system. The channel system most preferably is implemented as a coherent cavity. According to a first embodiment, the cylindrical chamber is implemented as a sleeve that is inserted in a boring located in a cylinder block.

Abstract: A device (1) for aspirating and dispensing liquid samples having a pump (2), which comprises a cylindrical chamber (3), a piston (4) movable in this cylindrical chamber, and a piston drive (5) engaging on the piston. The device additionally comprises a pulse generator (6), which effects dispensing of samples from a liquid by generating pressure waves in this liquid and a tip (8) connected via a line (7) with the cylindrical chamber (3), with the piston drive (5) comprising a first drive (9) and a second drive (10), implemented as a pulse generator (6). Such a device comprises a channel (27) for rinsing or flushing the cylindrical chamber (3), with the channel (27) discharging into the cylindrical chamber (3). Furthermore, the invention also concerns systems with, for example, 384 or more such devices that are arranged in an array.

Abstract: The invention relates to a seal (1) for separating a first chamber (2) from a second chamber (3) in a device (4) for aspirating and/or dispensing fluids (5), wherein the seal (1) is embodied to be ring-shaped and to act on an outer surface (6) of a piston (7), or on an inner surface (8) of a cylinder (9) of this device (4), and wherein the seal can be inserted into an annular groove (10) located in the outer surface (6) of the piston (7), or in the inner surface (8) of the cylinder (9). The seal (1) in accordance with the invention is distinguished in that it comprises a flat contact surface (12) embodied to rest against a flank (11) of the annular groove (10), a support area (13) freely projecting into the first or second chamber (2, 3), and a cylindrical sealing face (14).

Abstract: The ejection orifice (7) of a micropump including a baseplate (3) of glass and a cover plate (4) of silicon and intended for ejecting small liquid drops, has a diameter of about 50 &mgr;m, and is located in the center of a flat front surface (12) which, in order to avoid accumulations of liquid in the region of the ejection orifice (7), is only 8 times the area thereof and, along a continuous circular edge, is adjacent a lateral surface (13) in the form of an envelope of truncated cone. The front surface (12) and the lateral surface (13) have a surface roughness of not more than N4 and are provided, for example, with a hydrophobic plasma polymer coating.

Abstract: The invention relates to a seal (1) for separating a first chamber (2) from a second chamber (3) in a device (4) for aspirating and/or dispensing fluids (5), wherein the seal (1) is embodied to be ring-shaped and to act on an outer surface (6) of a piston (7), or on an inner surface (8) of a cylinder (9) of this device (4), and wherein the seal can be inserted into an annular groove (10) located in the outer surface (6) of the piston (7), or in the inner surface (8) of the cylinder (9). The seal (1) in accordance with the invention is distinguished in that it comprises a flat contact surface (12) embodied to rest against a flank (11) of the annular groove (10), a support area (13) freely projecting into the first or second chamber (2, 3), and a cylindrical sealing face (14).

Abstract: A device (1) for aspirating and dispensing liquid samples having a pump (2), which comprises a cylindrical chamber (3), a piston (4) movable in this cylindrical chamber, and a piston drive (5) engaging on the piston. The device additionally comprises a pulse generator (6), which effects dispensing of samples from a liquid by generating pressure waves in this liquid and a tip (8) connected via a line (7) with the cylindrical chamber (3), with the piston drive (5) comprising a first drive (9) and a second drive (10), implemented as a pulse generator (6). Such a device comprises a channel (27) for rinsing or flushing the cylindrical chamber (3), with the channel (27) discharging into the cylindrical chamber (3). Furthermore, the invention also concerns systems with, for example, 384 or more such devices that are arranged in an array.

Abstract: A delivery apparatus has, in a housing (13), a cannula (8) whose rear end is connected to a diluter (17) via a connecting tube (16). A piezoelectric actuator (10) increases in length under the action of a control signal and acts on a membrane (6) pierced by the cannula tip (9) and belonging to an interchangeable polypropylene pipette tip mounted on the delivery apparatus and adhering to the housing (13) by means of a collar (7) resting against said housing, and causing said membrane to sag, with the result that a drop of a sample liquid which was previously sucked in by means of the diluter (17) and whose accurately adjustable volume is between 1 nl and 1 &mgr;l is ejected from an outlet orifice (4). After a pipetting process the pipette tip is ejected by means of a slide (15). If the level of the sample liquid in the pipette tip always remains below the cannula tip (9), virtually no carry-over occurs.

Abstract: The ejection orifice (7) of a micropump including a baseplate (3) of glass and a cover plate (4) of silicon and intended for ejecting small liquid drops, has a diameter of about 50 &mgr;m, and is located in the center of a flat front surface (12) which, in order to avoid accumulations of liquid in the region of the ejection orifice (7), is only 8 times the area thereof and, along a continuous circular edge, is adjacent a lateral surface (13) in the form of an envelope of truncated cone. The front surface (12) and the lateral surface (13) have a surface roughness of not more than N4 and are provided, for example, with a hydrophobic plasma polymer coating.