Baxter Travenol Laboratories, Inc.

Rene G Lamadrid

C Michael Jennings

Albert Kitchenham

Herbert M Cullis

Charles I Soodak

Alan A Figler

Wendell V Ebling

David A Lohr

Stanley J Pernic

John J Selman, Iii

Earl G Phillips

David M Bergemann

A heater-scale having a curved supporting member upon which a bag of fluid to be heated can be placed, has a distributed two-dimensional heating element affixed to a lower surface thereof. The curved member is supported by a load cell for generating an electrical signal proportional to the weight of the bag on the heater member, a thermistor is in contact with the fluid whose temperature is to be maintained, a thermistor is affixed to the heater member, and a control system senses the weight and temperature of the bag of fluid as well as the temperature of the heater member for the purpose of nonlinearly adjusting the electrical current supplied to the heater element as fluid is removed from or variable temperature fluid is added to the bag so as to maintain the bag at a predetermined temperature.

Heater-scale for heating fluids for injection into a patient

A parenteral solution administration system having a conduit for communication with a source of parenteral solution, a drip chamber carried by the conduit, drop detector circuit for detecting drops falling through the drip chamber and flow control circuit including an occlusion device moving between first and second positions for opening and closing the conduit. Feedback circuit is provided for controlling the flow control circuit to cause the rate of drops falling through the drip chamber, as sensed by the drop detector circuit, to correspond to a predetermined drop rate. The occlusion device is preferably operated by a stepper motor, and the system is disengagable so that at the occurrence of a predetermined circumstance, the occlusion device can be disengaged from the motor circuit and can be moved without corresponding action of the motor circuit.

Motor driven occlusion controller for liquid infusion and the like

The vibration attenuation support assembly is utilized in a centrifugal liquid processing apparatus for supporting a rotor assembly, a non-rotatable arm fixed to and forming part of the support assembly and a prime mover and for attenuating vibrations created by an unbalanced mass in the rotating parts of the apparatus. The apparatus comprises a cabinet having sidewalls and a floor and a rotor assembly mounted on the support assembly mounted on the floor. Tubings are coupled directly between a source of the liquid outside of the rotor to receptacles within the rotor without the use of fluid seals and are supported from the stationary arm. The rotor assembly includes structure for guiding the tubings from the stationary arm to the rotor and a drive train mechanism and prime mover for rotating the tubings at a first speed and for rotating the rotor at a second speed twice the first speed. The support assembly includes a weldment for supporting the rotor assembly and prime mover and includes four elastomeric members for mounting the weldment on the floor. The support assembly has a mass greater than the unbalanced mass and in one embodiment the support assembly together with the rotor assembly and prime mover have a mass of approximately 150 kilograms and the unbalanced mass is 30 grams acting at a radius of 5 inches at a rotation of 1400 revolutions per minute.

Vibration attenuation support assembly for a centrifugal liquid

The assembly is utilized in a centrifuge device wherein a receptacle is received and held between first and second platens which are held within a platen holder fixed to the centrifuge device and in respective inner and outer parallel planes spaced radially outwardly from a vertical axis of rotation of the centrifuge device. The first platen is movable with one side wall of the holder about a generally horizontal axis extending along a lower edge of a second side wall of the holder. A latch mechanism provides for a toggle latching action between the walls as the latch mechanism is moved from an open position to a closed position. In one embodiment of the latch mechanism a handle is connected to a shaft journalled on the one side wall and mounts a plate on each end thereof with each plate having a pin extending therefrom that is rotated within a keeper member on an edge of the second wall to latch the platens in place. In another embodiment of the latch mechanism, two linkages are provided between the walls at the top of the holder. A linking pivot connection of each linkage is movable upwardly and then downwardly to allow the one side wall to be moved toward and away from the second side wall. Also in this embodiment the platens are inserted into the holder from the top thereof and this facilitates easy insertion and/or replacement or interchange of platens in the assembly. In the latched position, the one side wall is pressed against the platens.

Platen, holder and latch assembly for securing platens in place within a

An improved peristaltic pump includes a pivotably mounted pressure plate which, together with the pump roller elements, defines the pump chamber. The pivotal mounting of the pressure plate facilitates accessibility to the pump chamber in order to simplify the pump tube loading and unloading procedures. The mounting system for the pressure plate includes a mechanically-advantaged four-bar linkage arrangement which automatically retains the pressure plate in either its fully open or fully closed position as a result of an over-center type locking construction. The pump also includes a mechanism for adjusting the volume flow rate characteristic of a pump tube. This is particularly adaptable for a dual-tube system wherein a predetermined volume flow rate ratio is to be achieved.

Improved pressure plate movement system for a peristaltic pump

The optical detector is particularly adapted for use with an apparatus for separating blood into its components and is of the type including a centrifuge for centrifuging whole blood to separate same into the components thereof and of the type wherein plasma is withdrawn from the centrifuge through a flexible, light transmitting tubing and the spillover of red blood cells into the plasma withdrawn is monitored by the optical detector. The optical detector comprises a block having a slot across the top face thereof, the inner portion of the slot having a width less than the outer diameter of the tubing which is received in the slot such that when the tubing is pressed into the slot, it is squeezed from a circular cross section to an oval cross section to present two flat portions of the tubing adjacent opposite sidewalls of the slot. A first cavity is situated in the block behing a first sidewall of the slot and a second cavity is situated in the block behind a second sidewall of the slot. Apertures are provided in the sidewalls and light from a light source is directed along the axis of the apertures, through lenses in the cavities which seal the cavities from the slot and through the tubing in the slot from the first cavity to the second cavity where a photosensor is located. The photosensor is operable to generate an electrical signal which is indicative of the light sensed and which can be utilized for measuring the optical density of the plasma flowing through the tubing.

Optical density detector

The pressure monitoring assembly monitors changes in pressure of a fluid passing through the assembly. This is accomplished by passing a liquid through a pressure transfer device having first and second chambers therein separated by a flexible diaphragm. The first chamber has air therein and pressure changes are transmitted across the diaphragm from the second chamber through which the liquid flows. The assembly further includes a pressure transducer and a pressure coupling mechanism for coupling the pressure transfer device to the pressure transducer. The pressure coupling mechanism includes a body having a cylindrical chamber and a piston positioned for movement therein with a piston shaft protruding from a coupling end of the body. The shaft is biased outward from the coupling end of the body by a spring. The coupling end has an O ring seal which forms a seal with the pressure transfer device around an orifice in a wall of the second chamber when the pressure coupling mechanism is mounted to the pressure transfer device. The piston shaft has a through-bore to the cylindrical chamber so that air is trapped in an air passageway comprising the first chamber, the through-bore and the cylindrical chamber. As the pressure transfer device is latched to the pressure coupling mechanism, the shaft and piston are pushed against the spring toward the pressure transducer which is mounted to the body at one end of the cylindrical chamber thereby compressing the trapped air in the air passageway.

Pressure coupling mechanism in a pressure monitoring assembly

The latch assembly is utilized in a centrifuge device wherein a receptacle is received and held between first and second platens which have elastomeric linings and which are held generally upright in respective inner and outer parallel planes spaced radially outwardly from a vertical axis of rotation of the centrifuge device. The first platen is situated in the inner plane and the second platen is fixed in the outer plane. The first platen is mounted for pivotal movement about a generally horizontal axis extending along a lower edge of the platens. The latch assembly includes first and second keeper members fixed respectively to adjacent opposite sides of the second platen. The latch assembly further includes a shaft journalled to the outer surface of the first platen. First and second latch mounting members are fixed, respectively, to opposite ends of the shaft. A handle is fixed to and extends from the first latch mounting member and each of the latch mounting members has a pin extending therefrom, each pin bein adapted to be received in respective ones of the first and second keeper members. The construction, dimensions and arrangement of the various parts of the latch assembly are such that when the pins are moved into the keeper members, each moves along an arc which would normally intersect the associated keeper member such that an overcenter toggle latching action is obtained as the pins engage and are moved into the keeper members with the elastomeric linings being compressed to allow the overcenter latching action.

Latch assembly for latching platens in place within a centrifuge device

A device, which may be used in a dialysis system, is disclosed for separating low density material such as gas bubbles from a liquid by swirling the liquid, to cause the bubbles to migrate toward the center of the swirling liquid. A liquid storage chamber having side walls of generally circular cross-section of the longitudinal axis is provided. A port is provided for removing the bubbles or the like, positioned adjacent the longitudinal axis of the chamber. A liqud inlet passes into the chamber in such a position as to pass liquid into the chamber circumferentially about the side walls, to provide swirling of liquid passing into the chamber. In accordance with this invention, outlet means and pump means are provided for removing bubble-free liquid from the chamber at a point spaced from the inlet but adjacent the side wall. A first conduit conveys a portion of the bubble-free liquid so removed to a desired site of use, while a second conduit conveys the balance of the bubble-free liquid so removed back to the liquid inlet for reentry into the chamber, to enhance the swirling action of fluid in the chamber.

Device for separating low density material such as gas bubbles from a

A detector of blood in dialyzing solution, which operates by measuring the optical density of the dialyzing solution, is prevented from improper indication arising from the presence of bubbles in the dialyzing solution, by shaping the fluid passages to channel the bubbles away from the optical sensing path.

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Bethesda, MD, United States of America

Rene G Lamadrid