Abstract: A method of removing a constituent of a biological fluid including a blood component, said method including flowing the biological fluid past one side of a first semipermeable membrane; flowing solution containing a first precipitation agent past a second side of the membrane so as to cause transfer of the precipitation agent through the membrane to the biological fluid so as to improve precipitation characteristics of the fluid; and precipitating the constituent from the biological fluid. Also disclosed are maintaining a lower pressure in a biological fluid in a dialyzer than in dialysate at all portions of a membrane in the dialyzer and adding a continuously flowing stream of concentrated precipitation agent to a continuously flowing stream of a biological fluid.

Abstract: A peristaltic pump comprising a race having an internal surface for supporting a flexible tube in a tube pumping region, and a rotor rotatably mounted about a rotor axis and carrying rollers that travel in a circular path adjacent to the tube pumping region, the rollers having a large diameter central portion between smaller diameter portions to cause the tube to be self-aligning at the central portion. Also disclosed are a cover mounted on the race for movement in a direction parallel to the rotation axis between a loading position spaced from the race sufficiently to permit insertion of the tube through a tube insertion opening into a tube mounting region and an operational position in which the tube insertion opening is closed; and self-loading a tube into a peristaltic pump via rollers having a small diameter end portion and an adjacent larger diameter portion.

Abstract: Centrifuge drive apparatus including a support including a plurality of resilient mounting members that are spaced around a rotation axis and are intersected by a mounting plane that is perpendicular to the rotation axis, and a centrifuge bowl and drive motor assembly having a combined center of gravity in the vicinity of the mounting plane to reduce vibration.

Abstract: Dialysate preparation apparatus including dialysate and blood flow lines connected to a dialyzer, fluid control mechanisms on the lines to control conditions of fluid in the lines, fluid condition sensors on the lines to sense the conditions of fluid in the lines, a digital control processor receiving signals from the sensors and controlling the mechanism to achieve desired fluid conditions, and the digital monitor processor receiving signals from the sensors and verifying that fluid conditions meet predetermined safety limits.

Abstract: Using a membrane separating device to remove cell-free fluid from a suspension of cells to preconcentrate cells in the suspension prior to processing in a centrifuge.

Abstract: Apparatus for pumping fluid through plural flow lines comprising a pump having an inlet and an outlet for transporting the fluid therethrough, first and second flow lines that are selectively connectable to the pump inlet via a first valve, and third and fourth flow lines that are selectively connectable to the outlet via a second valve, whereby the pump can be used to selectively pump fluid through different flow paths.

Abstract: A self-loading peristaltic pump including a rotor rotatably mounted about a rotor axis, and a race having an internal surface for supporting a flexible tube in a pumping region between the rotor and the race, the surface including points that are at equal radii from the rotor axis in planes that are perpendicular to the rotor axis, the rotor including a roller for intermittently and progressively compressing the flexible tube against the race in the pumping region, the rotor including a radially extending rotor tab located outside of the pumping region for displacing the flexible tube toward the pumping region as the rotor rotates.

Abstract: Dialysate preparation apparatus having a main flow line having one end for connection to a source of water and another end for providing dialysate to a dialyzer, a concentrate flow line having one end connected to a junction on the main flow line and another end with a connector for alternatively connecting the concentrate line to a source of dialysate concentrate or a source of cleaning fluid, a source of dialysate connectable to the connector, a source of cleaning fluid having a cleaning fluid flow line with an end that is connectable to the connector, a flow sensing switch on the cleaning fluid flow line, and a controller connected to receive a signal from the switch to verify that the apparatus is in a cleaning mode when the switch indicates fluid flowing in the flow line. Also disclosed is a controller providing an initial backflush prior to pumping cleaning fluid into the apparatus in order to provide a water interface between the dialysate and the incoming cleaning fluid.

Abstract: Returning red blood cells to a patient after a centrifuge separation procedure by connecting an inflow line of a separation channel to an outflow line to provide a closed loop and recirculating liquid through it to remove blood cells. Also disclosed is pulling more liquid out of a flexible separation channel than permitted into it in order to reduce the volume of liquid to be used in returning cells to the patient.

Abstract: A peristaltic pump cartridge including a continuous flexible tube having two ends and a portion therebetween providing a U-shaped loop for use with a rotor and rollers to provide a peristaltic pump, a cartridge housing having supports for maintaining the portion of the flexible tube in the U-shaped loop external to the housing, the legs of the U-shaped loop leading into the housing, the housing having apertures through which connecting portions of the flexible tube remote from the U-shaped loop have been threaded from the interior to the exterior of the housing.

Abstract: A liquid conductivity sensor which features simply and inexpensively driving the excitation transformer of a two-transformer/fluid-loop remote conductivity sensor with a square wave excitation signal provided by a digital timer and a flip-flop. Also disclosed is using an electrodeless conductivity sensor to sense conductivity of dialysate.

Abstract: A pass-through tube for use in conveying intravenous fluid to a patient in a pressurized chamber, the tube including a tubular body having an outer surface shaped and sized to sealably mate with the interior surface of a connector passing through the wall of a pressurized chamber, a first end having a first generally cylindrical surface adapted to sealably engage a similarly shaped surface of a mating first connector and first locking members for locking with mating locking members on the first connector, a second end having a second generally cylindrical surface adapted to sealably engage a similarly shaped surface of a mating second connector and second locking members for locking with mating locking members on the second connector. Also disclosed is a kit including a pass-through tube, a flexible internal tube, and a valve connected to the external end for connection to an intravenous supply line.

Abstract: A membrane type blood oxygenating system with the membrane device, blood heater and blood reservoir constructed as an integral unit with the membrane device located lower than the blood reservoir.

Abstract: Dialysate preparation apparatus for mixing dialysate concentrate with water, the apparatus including a main flow line having one end for connection to a source of water and another end for providing dialysate to a dialyzer, a concentrate flow line having one end for connection to a source of dialysate concentrate and another end connected to a junction on the main flow line for adding concentrate to water in the main flow line, a volumetric pump having a fixed discharge volume per stroke on the concentrate line, a concentrate sensor on the main flow line downstream of the junction providing control signals to the pump to pump concentrate to achieve the desired concentration, and a controller including a comparator to compare the stroke rate with a limit indicating desired operating stroke rate range.

Abstract: Monitoring concentration of components of blood flowing through a flowpath including flowing the components through a transparent channel, directing light to the channel along an axis intersecting the channel, detecting light passing through the channel along the axis, detecting light scattered off of the axis, and determining concentration of components based on the light passing along the axis and/or the light scattered off of the axis. Also disclosed is a movable cover to block ambient light from a photodetector after mounting of a removable transparent flow channel.

Abstract: A fluid flow chamber cassette that can be mounted with either its front wall or rear wall against a supporting machine and has a flexible tube that extends from a sidewall and forms a loop that is symetrical about a loop axis that is transverse to the side wall so that the loop will be acted upon by a pump roller on the machine both when the front wall is against the machine and when the rear wall is against the machine. Also disclosed is automatically fixing the initial liquid levels and amounts of air in venous and arterial chambers of fluid flow transfer device apparatus by having the arterial chamber inlet enter the arterial chamber at a position higher than the arterial chamber outlet, having the venous chamber inlet enter the venous chamber at a position higher than the venous chamber outlet, and priming the apparatus by causing reverse flow, so that the liquid rises in the venous and arterial chambers to the level of the entrances of the inlets.

Abstract: A pump control apparatus including a variable speed pump controllable in response to a pump drive signal, a signal generator generating a commanded flowrate signal indicating desired flowrate of the pump, a flowrate sensor providing a sensed flowrate signal indicating sensed flowrate of the pump, and an integrator connected to the sensor and generator to receive and integrate the commanded flowrate signal and the sensed flowrate signal and to provide the pump drive signal based on the difference in integrated values of the signals so as to achieve desired commanded volume over time.

Abstract: A diaphragm and chamber device including chamber means for defining a chamber having fixed position walls on opposite sides, a diaphragm in the chamber and sealably mounted between the walls to define first and second regions therein on opposite sides of the diaphragm, the diaphragm being movable in the chamber so as to change the volume of the two regions as the diaphragm moves toward either the wall, a magnet carried by the diaphragm and movable therewith, and a magnet position sensor carried by a the wall and sensing the location of the magnet and thus the diaphragm.

Abstract: A diaphragm for use in a fluid flow chamber comprising a generally flat flexible sheet that is engageable at its periphery and has a central portion that is reciprocally movable along an axis perpendicular to a plane through the periphery, the flexible sheet having annular corrugations around the center portion, and a magnet secured to the center of the sheet, the magnet having a front and a rear, the corrugations causing the front and rear to maintain their orientation with respect to the axis as the central portion travels along the axis.

Abstract: A fluid flow chamber cassette that can be mounted with either its front wall or rear wall against a supporting machine and has a flexible tube that extends from a sidewall and forms a loop that is symmetrical about a loop axis that is transverse to the side wall so that the loop will be acted upon by a pump roller on the machine both when the front wall is against the machine and when the rear wall is against the machine. Also disclosed is automatically fixing the initial liquid levels and amounts of air in venous and arterial chambers of fluid flow transfer device apparatus by having the arterial chamber inlet enter the arterial chamber at a position higher than the arterial chamber outlet, having the venous chamber inlet enter the venous chamber at a position higher than the venous chamber outlet, and priming the apparatus by causing reverse flow, so that the liquid rises in the venous and arterial chambers to the level of the entrances of the inlets.