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 manual pipette including a delayed action home position latch for engaging only after the plunger unit of the pipette has moved downward through its home position to thereafter releasably connect a moveable bottom stop member to the plunger unit to move therewith and upon an upward return of the plunger unit by the pipette's return spring to engage a home position stop to releasably lock the plunger unit in its home position without any downward force being exerted by the pipette user on the plunger unit.

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 reusable pipette tip rack for successively receiving and dispensing arrays of pipette tips and including a manually releasable latch mechanism for securing a support plate carrying an array of pipette tips flat on the top of a support tray of the pipette tip rack with the array of tips seated in an array of openings in the top of the support tray. The latch mechanism comprises a latch including a laterally extending locking surface on one of the support plate or the support tray and a manually releasable locking member extending from the other of the support plate or the support tray. Preferably, the latch mechanism comprises a combination of two such latches each including a locking member and locking surface located at opposite edges of the support tray of the pipette tip rack.

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 manual pipette including user controllable latch and trigger mechanisms for releasably locking the plunger of the pipette in a "home" position ready for immersion of the pipette tip in a fluid to be drawn into the tip and further including a user controllable velocity governor for regulating the rate of plunger return from the "home" position to a first or upper stop position in drawing the fluid into the tip.

Abstract: A liquid chromatography column apparatus which utilizes sorbent packing material in a tube having a first end portion and a second end portion. The first end portion of the tube includes a plug having a passage therethrough. The plug fits in the tube adjacent the packing material and is movable within the tube. An end fitting is also employed adjacent the plug. The end fitting has a passage therethrough which communicates with the passage of the plug. A seal is used inside the tube between the tube and the end fitting. The second end portion of the tube is enclosed and also includes a passage from the interior to the exterior of the tube. A manually actuable gear mechanism is incorporated in the end fitting of the first end portion of the tube for facilitating application of axial force to the packing material, thereby compressing the packing material so as to eliminate voids and channels in the packing material. Other features are also disclosed.

Abstract: A multichannel air-displacement pipette liquid-end assembly having a modular construction, which enables individual components to be easily replaced when they become contaminated or worn. The modular liquid-end assembly also enables selected piston and cylinder components to be selectively removed so that any one of a number of predetermined multichannel pipetting configurations can be employed. Additionally, the modular liquid-end assembly preferably comprises an ejector for providing low-friction mechanical advantage in order to facilitate dislodging spent tips.

Abstract: A dashpot piston mounted in a closed chamber is coupled by an axially movable shaft to a pipette piston to regulate return movement of the pipette piston within a pipette cylinder to draw fluid into the cylinder. The dashpot shaft is movable within limits relative to the dashpot piston to accommodate a blow-out of residual fluid from the pipette by the shaft driving the pipette piston beyond a home position to blow residual fluid from the pipette cylinder. An air inlet port in the bottom of the chamber allows air to be drawn into the chamber with upward movement of the dashpot piston while a valve adjacent to the air inlet port opens in response to downward movement of the dashpot piston to exit air from the chamber. Control of the relative sizes of the air inlet port and valve outlet regulates the relative rates of upward and downward piston movement in the cylinder.

Abstract: An enclosed pipette tip rack utilizing a container having a bottom and a side portion connected to the bottom which extends upwardly and terminates in a top. A tray is supported by the container and holds at least one pipette tip such that a portion of the pipette tip lies within the container. A cover is also included and is supported by the container adjacent the tray. The container and cover are vented to the ambient environment.

Abstract: A liquid chromatography column apparatus which utilizes sorbent packing material in a tube having a first end portion and a second end portion. The first end portion of the tube includes a plug having a passage therethrough. The plug fits in the tube adjacent the packing material and is movable within the tube. An end fitting is also employed adjacent the plug. The end fitting has a passage therethrough which communicates with the passage of the plug. A seal is used inside the tube between the tube and the end fitting. The second end portion of the tube is enclosed and also includes a passage from the interior to the exterior of the tube. A manually actuable gear mechanism is incorporated in the end fitting of the first end portion of the tube for facilitating application of axial force to the packing material, thereby compressing the packing material so as to eliminate voids and channels in the packing material. Other features are also disclosed.

Abstract: A chromatography column apparatus which utilizes sorbant material in a tube which has a first and second end portion. The first end portion of the tube includes a plug having a passage through the same. The plug fits in the same, adjacent the sorbant material, and is movable within the tube. An end fitting is also employed which has a portion that is placed within the tube adjacent the plug. The end fitting has a passage therethrough which communicates with the passage of the plug. A seal is used inside the tube between the plug and the end fitting. The end fitting and plug are held together. The second end portion of the tube is enclosed and also includes a passage from the interior to the exterior of the tube.

Abstract: An enclosed pipette tip rack utilizing a container having a bottom and a side portion connected to the bottom which extends upwardly and terminates in a top. A tray is supported by the container and holds at least one pipette tip such that a portion of the pipette tip lies within the container. A cover is also included and is supported by the container adjacent the tray. The container and cover are vented to the ambient environment.

Abstract: A chromatography column apparatus which utilizes sorbant material in a tube which has a first and second end portion. The first end portion of the tube includes a plug having a passage through the same. The plug fits in the same, adjacent the sorbant material, and is movable within the tube. An end fitting is also employed which has a portion that is placed within the tube adjacent the plug. The end fitting has a passage therethrough which communicates with the passage of the plug. A seal is used inside the tube between the plug and the end fitting. The end fitting and plug are held together. The second end portion of the tube is enclosed and also includes a passage from the interior to the exterior of the tube.

Abstract: A fluid control mechanism utilizing a housing having an opening or tunnel through the interior of the same. The housing provides at least one chamber communicating with the housing opening. A seat positions within the housing opening and the chamber. A plug, adapted to occupy the seat and close to restricted passage, positions within the first chamber. Particulate filter means comprising a pressure deformable section which includes a passage to the housing opening partially filled by a relatively rigid filter element. A gap in the filter means passage allows compression of the deformable section.