Abstract: A method and apparatus for aspirating and dispensing precise volumes of liquid, e.g. whole blood, comprises an aspiration probe or needle having an internal volume precisely equal to a desired volume to be dispensed, and a computer-controlled shear valve for trapping aspirated liquid inside the probe for subsequent dispensing. A liquid sensor positioned downstream of the shear valve cooperates with a liquid level sensor on the probe tip to assure that the probe lumen is filled with the aspirated liquid.

Abstract: A method for sampling, metering and delivering precise microliter volume aliquots of a liquid blood sample to mixing and testing means of an electronic blood analysis system for analysis using a sampling and metering valve assembly in which is defined plural through fluid flow paths, one of the flow paths including a loop for metering and isolating a sample aliquot therein, the method comprising the steps of defining first and second dedicated passages within the valve assembly displaced one from the other and from the loop containing the isolated aliquot, introducing an inert gas to the loop to force the aliquot therein to said first dedicated passage at the displaced location thereof, placing the first and second dedicated passages in communicating relationship and introducing lyse reagent to the second dedicated passage to force the isolated aliquot from the first dedicated passage with the lyse reagent to a location exterior of the valve assembly without contaminating any flow paths which has been travers

Abstract: A liquid metering and transfer valve assembly having the capability of metering, isolating, transfering and delivering precise microliter volume aliquots of a blood sample, from a source thereof, to mixing and testing chambers of an electronic blood analysis system for analysis, and further, carrying a loop for metering and isolating an additional sample aliquot within the valve assembly in the loop, a first dedicated passageway for introducing a first fluid to the loop to force the additional aliquot from its isolated location to a first dedicated portion of the valve assembly displaced from the loop and a second dedicated portion of the valve assembly to establish a flow path for introducing a lysing reagent to the first dedicated portion to force the additional aliquot from its displaced disposition, as a lyse reagent/aliquot mixture, to a selected additional mixing and testing chamber exterior of the valve assembly without contaminating any interior flow path traversed by a blood sample and associated dil

Abstract: A rotary liquid metering and transfer valve assembly for a diluting system which includes a pair of stationary valve disc elements sandwiching a central, rotatable valve disc element, said disc elements being coaxially aligned and mounted on a spindle. One of the outer stationary elements has a first external loop secured thereto, said loop having a precise interior volume. An aspirator probe is secured to the other of said stationary elements. The central element has formed therein an axial segmenting passageway having a precise interior volume. A second external loop is secured to the center element. The second loop extends outwardly, preferably radially, of said element and has a precise interior volume. Appropriate interior passageways are provided in the outer elements for directing a liquid sample in a continuous path through the valve assembly, the path including the one segmenting passageway and the first and the second external loops.

Abstract: A liquid diluting and transfer valve has disc like valve elements provided with faces frictionally engaged. The valve further includes passageways for passing both sample liquid and rinse liquid and a continuous groove formed in one of the respective faces. This continuous groove effectively isolates the passageway openings to the faces and is capable of blocking passage of leakage material along the face to the periphery of the engaged face.

Abstract: A molded flexible fluid conduit and a make/before break pinch valve including a slidably movable pressure member spring biased normally against said conduit in closed condition of the valve, said conduit including a pair of elongate longitudinal unitary purchase formations capable of cooperating with slots carried by the valve whereby the conduit forcibly is pulled or stretched in diametrically opposed directions upon actuation of the valve subsequent to periods of closure so as to force the conduit open to permit flow.

Abstract: A liquid diluting valve assembly for delivering a pair of different sample volumes in the microliter range along with a predetermined volume of diluent to different locations. The valve assembly includes a pair of outer discs and an inner disc sandwiched therebetween, the facing surface portions being sealingly frictionally engaged. The discs have central axial passages aligned to accommodate a spindle the inner disc being independently movable relative to the other discs. The discs carry passageways with at least one segmenting passageway provided in the inner disc. One of the outer discs is stationary and carries an external hollow loop having a precise volume in the microliter range. The other outer disc carries a single outwardly extending aspirator probe for introduction of a liquid sample from an exterior sample source, the probe being coupled in series with the external hollow loop.

Abstract: A liquid transfer rotary valve assembly capable of measuring and delivering at least a pair of different sample volumes in the microliter range along with a predetermined volume of diluent as a pair of different dilutions directed to different locations. The valve assembly provided herein includes a pair of stationary outer disc members and a movable inner disc member sandwiched therebetween, the facing surface portions being sealingly frictionally engaged. Each disc has an axial central passage to accommodate a spindle. An external hollow loop is provided on one of the stationary discs having a precise volume in the microliter range. A segmenting passageway is provided on the movable inner disc member. A source of sample is communicatively coupled through the other stationary disc to the segmenting passage which is arranged in series with the external loop.

Abstract: A sample feeding arrangement which receives sealed sample tubes, moves them one at at time to a seal piercing and sample aspiration station, and then discharges the used tubes. This sample feeding arrangement is mounted inside a sample analyzer of the type which previously had operated semiautomatically. Receipt of a sample tube at the infeed station of this feeding arrangement initiates the repositioning of the tube to an aspiration station, which thereat enables all other handling steps of the tube, sample aspiration, and the full system cycle of the analyzer.

Abstract: Improvements in a backwash system for diluting apparatus wherein a rinse solution is directed to and through a sample pick-up probe to a receptacle and therefrom to a waste depositary. Either the probe or the receptacle in turn is movable between a first uncoupled condition, along a predetermined or fixed path first to place the receptacle and the delivery end of the sample probe proximate, and second, to establish a fluid tight sealed coupling therebetween. The receptacle includes an entrance recess accommodating an apertured resilient insert which engages the delivery end of the probe to define the sealed coupling. A sensing switch is employed to assure that the rinse solution will not be dispensed as backwash unless the sealed coupling is known to have been established.

Abstract: A liquid transfer valve assembly capable of measuring and transferring plural different volumes from a sample source to defined flow paths under the influence of pressurized fluid. The preferred valve assembly includes a pair of stationary outer disc members and a movable inner disc member sandwiched therebetween, their facing surfaces sealingly frictionally engaged. Each of the discs has a central axial passage arranged for mounting on a spindle, with the sandwiched disc having a radial pin entering its axial passage for cooperation with a slotted spindle, the rotation of the spindle rotating only said sandwiched disc relative between a pair of positions. The center disc carries at least a segmenting bore pair, at least one of the bores being a measuring passage and having a precise volume. A matching port pair is provided in each of the outer discs defining flow paths through the valve arranged selectively to be intercepted by said measuring bore of the segmenting bore pair.

Abstract: Improvements in a backwash system for diluting apparatus wherein a rinse solution is directed to the fluid transfer valve thereof and thence back to and through the sample pick-up probe to a receptacle and then to a waste depositary. The receptacle is mounted on a carrier, in turn mounted for movement in a track from a recessed condition, along a path directed first outward and then upward to engage the delivery end of the sample probe in a fluid tight sealed coupling. A plunger of an air cylinder effects the movement of the receptacle in the track. A vacuum operated switch is employed to assure that the rinse solution will not be dispensed as backwash unless the sealed coupling is made. Alternatively, a microswitch can be substituted for the vacuum operated switch and presented in the path of the carrier to be actuated when the carrier has moved sufficiently to establish the sealed coupling between the receptacle and the delivery end of the sample probe.

Abstract: A few large, fast rising gas bubbles are generated near the bottom of a sample container and the upward movement of the bubbles causes a mixing action of the sample. The bubbles result from the periodic injection of discrete quantums of gas into the bottom of the container. The volume of a discrete gas quantum determines the size of a resulting bubble. Both the volume and frequency of generation of the quantums of gas are controlled by a timing circuit which operates a solenoid valve that permits each discrete quantum of gas to pass into the sample container.