Abstract: The present invention relates generally to a multichannel pipetting system that can be used with a plurality of well plates used for medical, biological or biochemical research involving liquid materials. The system includes a multichannel pipettor and novel pipette tips having a crown that can be fitted over the opening of more than one channel. The multichannel pipettor may optionally be provided with an array of air pressure channels placed among the array of pipetting channels and enables the pipettor to aspirate and dispense a crude large volume of liquid material through the novel pipette tips of the present invention.

Abstract: A fluid transfer device includes a cylinder and a displacement rod. The cylinder is fabricated rigid enough to minimize distortion of volume yet compliant enough to create a seal between itself and the surface of the displacement rod. The cylinder is constructed with a bore hole through its central portion running from end to end. The diameter of the bore hole is larger than the diameter of the displacement rod. The displacement rod is constructed of a rigid material. At least one end of the cylinder has a diameter reduced so the diameter of the bore hole and the diameter of the displacement rod are substantially the same to form a seal with each other. As the displacement rod is withdrawn from the bore hole, a sample is drawn into the bore hole. The volume of the sample drawn into the bore hole is a function of the volume of the displacement rod withdrawn from the bore hole. A cross hole, for venting undesired fluid such as gas bubbles or previous sample(s), is located on the displacement rod.

Abstract: A fluid level sensor and a washer unit are provided for an automated immonoassay processing system. A washer head (13) is vertically movable by a drive (2) above a reaction tray (8) having fluid (15) in separate cells. The level sensor comprises two electrodes arranged along a fluid path within aspirator tips (6). The electrodes are held at different electrical potentials and are effectively insulated from each other. If fluid is aspirated along the fluid path then the electrodes are bridged. Control means (1) is arranged to detect any change in conductance between the electrodes thereby indicating the presence of fluid (15). The vertical height of the washer head is determined relative to the sample thereby enabling the device to determine the level of the fluid (15).