Abstract: Disclosed are apparatus adapted to dispense and/or aspirate liquids, such as in a clinical analyzer. In one aspect, a multi-chamber pump apparatus is disclosed that has a pump body containing first and second chambers, a piston having a first piston portion of a first pump area A1 received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, and an actuator coupled to the piston. The first and second chambers can be selectively accessed to improve metering accuracy at dissimilar flow volumes from the chambers. Methods and systems including the multi-chamber pump apparatus are provided, as are other aspects.

Abstract: A highly accurate pumping device for aspirating and dispensing variable volumes of fluid is presented. The pumping device comprises a housing with a slotted optical sensor, a stepper motor with a fine pitch lead screw, a coupling linking the stepper motor shaft and the lead screw, an anti-backlash nut, an anti-rotation arm linking the plunger with the anti-backlash nut, an end of travel sensor feature integrated in the arm, and a top which incorporates a chamber and a lead screw bearing. A seal, located in the top, seals against the plunger and the chamber. The plunger is attached to the anti-rotation arm and eccentrically aligned to the lead screw. The pumping device further includes one or more ports through which fluid may be introduced into or out of the chamber. The pumping device may be easily changed to accommodate different full-scale volume requirements due to the self-aligning features.

Abstract: A poppet valve apparatus is structured to reduce the rate of build-up of fluid-borne debris within its internal architecture. The inlet and outlet ports are arranged tangential to the internal cylindrical walls defining the valve's flow chambers, whereby a circular flow pattern is produced within the valve interior, and a specially contoured flow director efficiently redirects the circular flow pattern through a circular annulus defined by a valve seat and a sealing ring.

Abstract: An apparatus for automatically drawing a blood sample from a sealed container having an internal pressure below that of atmospheric pressure comprises an aspirating needle which serves to pierce the sealed container to aspirate liquid from the container, and to vent the interior of the container to the surrounding atmosphere through a suitable vent line connected to the needle. Such apparatus further comprises a vacuum pump connected to the needle through an aspiration line for aspirating blood from the sealed container. To warn the user of the possibility that fluid (e.g. cleansing diluent) in the aspirating needle has been drawn into the sealed container in the event of a vent line failure, apparatus is provided for detecting the pressure in the container immediately after the aspirating needle has pierced the container seal, and for comparing this pressure with a predetermined nominal value (typically, the negative pressure rating of the vacuum pump).