Abstract: A refill pack of light weight low mass material containing an array of replacement pipette tips for a reusable tip rack. The refill pack comprises a support plate with an array of holes containing pipette tips arranged in an organized manner and including a guide for centering and guiding the support plate onto the tip rack with distal end portions of the pipette tips aligned with corresponding holes in an organizing tray in the tip rack, the support plate including vertically extending lateral support means adjacent at least some of the holes in the plate to engage sides of the pipette tips to laterally support such tips against lateral rocking on the plate.

Abstract: An air displacement pipette having axially spaced annular sealing and frusto-conical lateral support zones and regions on the pipette's mounting shaft and tip, respectively, in combination with structure for insuring uniform depth of mounting shaft penetration into the pipette tip to maintain uniform tip interference with the mounting shaft as successive tips are mounted on and ejected from the mounting shaft whereby the pipette tip is easily and firmly mountable on and ejectable from the pipette tip mounting shaft by the application of reduced user generated axial forces.

Abstract: A plastic pipette tip easily and firmly mountable on and easily ejectable from a pipette mounting shaft of a pipette by application of relatively small axial mounting and ejection forces of about six and three (3) pounds respectively. The pipette tip includes a tubular proximal portion comprising (i) a frusto-conical open upper end portion having an inner diameter at its upper end greater than the diameter of a mounting shaft of the pipette to which the pipette tip is to be mounted, (ii) a hollow mid-portion and (iii) an annular sealing region at a junction of the open end and mid-portions. The annular sealing region has an inner diameter less than “x” and is designed to engage a lower end of a sealing zone of the mounting shaft to stretch radially outward as the mounting shaft is guided and stably oriented in the proximal portion thereby creating a fluid tight seal between the sealing zone and the sealing region.

Abstract: An air displacement pipette having axially spaced annular sealing and substantially cylindrical lateral support zones and regions on the pipette's mounting shaft and tip, respectively, in combination with structure for insuring uniform depth of mounting shaft penetration into the pipette tip to maintain uniform tip interference with the mounting shaft as successive tips are mounted on and ejected from the mounting shaft whereby the pipette tip is easily and firmly mountable on and easily ejectable from the pipette tip mounting shaft by the application of axial mounting and ejection forces of about two pounds and one pound, respectively.

Abstract: An air displacement pipette having axially spaced annular sealing and substantially cylindrical lateral support zones and regions on the pipette's mounting shaft and tip, respectively, in combination with structure for insuring uniform depth of mounting shaft penetration into the pipette tip to maintain uniform tip interference with the mounting shaft as successive tips are mounted on and ejected from the mounting shaft whereby the pipette tip is easily and firmly mountable on and easily ejectable from the pipette tip mounting shaft by the application of axial mounting and ejection forces of about two pounds and one pound, respectively.

Abstract: A membrane filter pipette tip comprising a hollow tube having a relatively large open upper end for seating on a lower end of a pipette tip mounting shaft of a pipette device and having a relatively small lower open end for passing fluid into the lower end of the tube upon operation of the pipette device in an aspiration mode. A porous membrane is secured by a porous plug within the tube across an open channel within the tube extending between the open upper and lower ends thereof and having a fluid initiation/penetration pressure which is greater than the maximum vacuum pressure which the pipette device to which the tube is secured is capable of generating.

Abstract: A replaceable pipette tip comprising a pipette surface contamination protector comprising an upwardly extending projection connected by the shoulder to the proximal end portion for laterally spacing the pipette device from a tube which contains or which is to receive the sample fluid to prevent contamination of an outer surface of the pipette device by contact with the tube into which the pipette tip is inserted.

Abstract: A plurality of large maximized internal volume freely nestable pipette tips for mounting in a standard pipette tip rack or refill pack including a horizontally extending pipette tip support having a plurality of through holes arranged in an array, each hole having a center which is spaced a distance "s" from centers of immediately adjacent through holes, each pipette tip having a substantially cylindrical proximal portion and an elongated generally conical distal portion coaxial with and joined to its proximal portion adjacent a downward facing outwardly extending shoulder and including at a distal end of the tip a relatively small orifice for receiving and dispensing fluid into and from the pipette tip upon operation of a pipette to which the pipette tip is mounted, the proximal portion of each pipette tip having an outer diameter equal to or slightly less than "s" and a slightly conical inner surface for tightly receiving and releasably attaching to a pipette tip mounting shaft of a large volume pipette and

Abstract: A refill pack for storing and dispensing pipette tips into a tip rack, comprising a support plate with an array of holes containing disposable pipette tips arranged in an organized array and a carrier for hand positioning the support plate over the tip rack for release of the array of pipette tips into the tip rack.

Abstract: A refill pack of light weight low mass material containing an array of replacement pipette tips for a reusable tip rack. The refill pack comprises a support plate with an array of holes containing pipette tips arranged in an organized manner and including a skirt-like guide for centering and guiding the support plate onto the tip rack with distal end portions of the pipette tips aligned with and vertically entering corresponding holes in an organizing tray in the tip rack.

Abstract: A pump is described in which a flexible enclosure defines a pump chamber whose contents are expelled by movement of a pusher plate engaged with the enclosure. The pusher plate is moved by an elongate beam spring interconnecting the pusher plate with a solenoid drive mechanism. Solenoid actuation causes flexing of the beam spring from a relatively less stressed to a relatively more stressed position, the increased stress in the spring being relieved by pusher element movement. A preferred embodiment of the invention includes a symmetrical arrangement of opposed pusher elements and associated beam springs.

Abstract: A pump is described in which a flexible enclosure defines a pump chamber and in which the contents of the pump chamber are expelled by movement of a pair of opposed pusher elements engaged with the enclosure. The pusher elements are displaced by at least one pair of beam springs, each of which is pivotally supported at one end and is engaged with one of the pusher elements at the other end. The ends of the beam springs opposite the pusher elements are pivoted by actuation of symmetrical solenoid armatures, causing each of the springs to be stressed. Relief of the spring stress forces the pusher elements toward each other. De-energization of the solenoid armatures permits the beam springs to pivot back to the original position upon filling of the pump chamber.