Abstract: An air displacement pipette having axially spaced annular sealing and lateral support zones and regions on the pipette's mounting shaft and tip, respectively, the annular sealing zone comprising an annular sealing surface outward of an outer surface of the mounting shaft at a lower end thereof and a sidewall of the pipette tip in the sealing region being sufficiently thin as to expand slightly and form an interference fit and air tight seal between the sealing surface and the sealing region when the sealing zone penetrates the sealing region and an outer diameter of the mounting shaft in the lateral support zone being equal to or slightly greater than an outer diameter of the pipette tip in the lateral support region to produce an secondary interference fit or air tight seal between the mounting shaft and pipette tip.

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 means 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 bilaterally symmetrical lightweight hand holdable battery powered microprocessor controlled electronic pipette including an axially elongated hollow housing having a vertically extending longitudinal axis. An upper portion of the housing includes a forward compartment containing a forwardly facing electronic display, a plurality of forwardly facing control keys and at least one forwardly facing trigger switch arranged in a vertically spaced pattern such that a pipette user in gripping a lower handle portion of the housing in either his or her right or left hand can easily reach with his thumb the control keys, trigger switch(es) as well as a push button of a pipette tip ejector.

Abstract: A bilaterally symmetrical lightweight hand holdable battery powered microprocessor controlled electronic pipette including an axially elongated hollow housing having a vertically extending longitudinal axis. An upper portion of the housing includes a forward compartment containing a forwardly facing alpha-numeric display, a plurality of columns of forwardly facing control keys and plurality of forwardly facing trigger switches arranged in a vertically spaced pattern such that a user in gripping a lower handle portion of the housing in either his or her right or left hand can easily reach with his thumb the control keys, trigger switches as well as a push button of a pipette tip ejector.

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: A battery powered, microprocessor controlled portable electronic pipette, comprising a hand holdable housing supporting a battery, a linear actuator for driving a plunger lengthwise in a cylinder to aspirate and dispense fluid into and from a pipette tip extending from the housing and a control circuit for the linear actuator. The linear actuator is powered by the battery and comprises a stepper motor with current receiving windings for electromagnetically driving a rotor to impart the lengthwise movement to the plunger.

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 refill pack for storing and dispensing pipette tips into an empty tip rack. The refill rack comprises a hand-gripable carrier for an array of pipette tips releasably secured relative to the carrier such that after hand positioning the array of tips on the empty tip rack, the carrier may be released from the tips which are then free to be seated on a lower end of a pipette and removed from the tip rack.