Abstract: A monitoring system for monitoring trans-membrane pressure in plasmapheresis apparatus utilizing a microporous membrane type filter includes first and second pressure-to-frequency transducer circuits for developing signals frequency-indicative of the inlet and outlet pressures of the filter. The signals are digitally compared in a pulse subtraction circuit to produce an output signal frequency-indicative of trans-membrane pressure. The output signal is applied to a periodically reset display counter to develop a digital readout of trans-membrane pressure. Porous filter elements in the flow system and in the inlet port of each transducer isolate bacteria within the flow system, prevent contamination of the transducers, and provide a time constant for each transducer which prevents transient flow variations in the system from causing erroneous trans-membrane pressure readings.

Abstract: An implantable microinfusion pump system for dispensing medication at a prescribed infusion rate within the human body includes a hermetically sealed housing in which a power source and circuitry for actuating the pump are contained. A permanently magnetized piston is mounted for reciprocative fill and pump strokes within a pump chamber defined by a pump body member which extends between parallel-spaced walls of the housing. The body member communicates at one end with an expandable medicament reservoir adjacent one wall of the housing, and at the other end with a catheter for conveying medicament to the body. A two stage valve arrangement causes medicament to enter the pump chamber during fill strokes of short duration and to be dispensed from the pump chamber at the prescribed infusion rate during longer duration pump strokes.

Abstract: An apparatus for separating and collecting plasma from whole blood includes a collection rate monitoring system which provides a digital display of the rate of plasma collection per minute. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma. The frequency of this signal over a present measurement interval is periodically compared with the frequency of the signal over a preceding measurement interval to develop a signal indicative of the volume of plasma collected during the interval. This signal is combined in a shift register with signals developed over a plurality of immediately preceding measurement intervals, which, taken with the present interval, comprise a one minute period, to develop at the end of each interval an output signal indicative of the total units of plasma collected over the previous minute.

Abstract: A runway collision avoidance system having warning devices is provided for the safety of aircraft taxiing, taking off, and landing. The system is capable of detecting ground traffic and obstacles including aircraft, maintenance vehicles and wildlife that may encroach upon an active runway during low visibility conditions or when visual observation is impaired. The system includes an electromagnetic transmitter positioned beyond one end of a runway which directs a continuous beam of high frequency radio signals, for example microwaves, longitudinally along the full length of the runway. A plurality of electromagnetic receivers positioned beyond the other end of the runway pick up the transmitted signals and apply them to a balance circuit and then to a comparator circuit. With a clear runway, the transmitted signals are received without interruption and the receiver outputs remain balanced or equal.

Abstract: A fluid processing apparatus for use in conjunction with a disposable fluid processing module of the type which includes an integral housing wherein fluid containers, tubing segments, and other components required in processing a fluid are contained, and wherein fluid communication between the containers, components and tubing segments is provided by a fluid circuit formed by a panel of the housing, and an overlying fluid-impermeable flexible sheet member. The processing apparatus includes an actuator station for receiving the module housing, and pneumatic actuator ports which apply pressures to pump and valve elements in the fluid circuit to circulate fluid through the system.

Abstract: A disposable prepackaged fluid processing module includes an integral housing wherein fluid containers, tubing segments, and other components required in processing a fluid are contained. Fluid communication between the containers, components and tubing segments is provided by a fluid circuit formed by a panel of the housing, and an overlying fluid-impermeable flexible sheet member. The fluid circuit includes pump and valve elements which operate in response to pressures applied to the sheet member. Upon installation of the system in a related actuator apparatus pneumatic actuator ports apply pressures to the pump and valve elements to circulate fluid through the fluid circuit.

Abstract: A fluid processing apparatus for use in conjunction with a prepackaged disposable fluid processing module of the type which includes an integral housing wherein fluid containers, tubing segments, and other components required in processing a fluid are contained, and wherein fluid communication between the containers, components and tubing segments is provided by a fluid circuit formed within the housing by a first relatively inflexible fluid-impervious sheet member and a second relatively flexible fluid-impermeable sheet member. The fluid circuit includes pump and valve elements which operate in response to pressures applied to the second sheet member. Upon installation of the system in the processing apparatus pneumatic actuator ports apply pressures to the second sheet member through access apertures in the housing to circulate fluid through the fluid circuit.

Abstract: An apparatus for separating and collecting plasma from whole blood includes a volume monitoring system which provides a continuous display of the volume of plasma collected. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma. The frequency of this signal over a present measurement interval is periodically compared with the frequency of the signal over a preceding measurement interval to develop a difference signal. If the difference is determined to be positive and less than a predetermined maximum collection rate so as to constitute a valid collection increment, the difference is cumulatively added to previous collection increments in a cumulative display counter to provide a collected volume display, and the frequency of the present measurement interval is taken as a frequency of the preceding measurement interval for the next comparison.

Abstract: An apparatus for the continuous flow fractionation of whole blood incorporates motor driven whole blood, anticoagulant and replacement pumps, negative and positive pressure monitors, and a dual bubble detector which function in conjunction with a disposable single-use flow system and a hollow fiber filter to separate and collect plasma from whole blood. Operation of the pump motors, pressure monitors and bubble detector is controlled by a control circuit within the apparatus to provide one of several operator-selected operating modes, including run, prime and reinfuse modes. The control circuit provides an alarm which can be cancelled by the operator when certain system parameters fall outside of normal operating limits, and interrupts operation of the pumps when the parameters exceed maximum limits. A failsafe circuit independent of the control circuits interrupts power to the pump motors in the event the motors do not stop upon detection of a bubble or fluid absence in the flow system.

Abstract: Metering apparatus for metering the flow of fluid through an administration set includes a peristaltic-type metering pump which repeatedly and progressively compresses a section of vinyl tubing of the administration set to provide a desired flow rate. For improved metering accuracy the fluid is maintained under pressure downline of the metering pump by a downline occlusion station. A protective circuit responsive to the pressure in the tubing downline of the occlusion station stops the metering apparatus and sounds an alarm in the event the pressure in the tubing exceeds a predetermined level, as in the event of an occlusion, downline of the metering apparatus and upline of the patent.

Abstract: A system for use in flow metering apparatus for detecting bubble formation in both clear and opaque fluids in an administration set includes a light source and a light detector positioned on opposite sides of a transparent tubing segment of the administration set such that light transmitted through the tubing to the detector is dependent on the presence or absence of fluid in the tubing. With clear fluid present, a first comparator in the system interrupts operation of the metering apparatus when the light detector output falls below a predetermined minimum level. With opaque fluid present, a second comparator interrupts operation of the apparatus when the light detector output rises above a predetermined maximum level. The detection system is automatically conditioned to either clear or opaque operating modes without input from the operator, and incorporates protection circuitry for interrupting operation of the metering apparatus in the event of failure of either the light source or the light detector.

Abstract: In a flow metering apparatus, a bubble detector for detecting bubble formation in tubing includes a light source and first and second light detectors. The first light detector is positioned on the opposite side of the tubing from the light source such that the light transmitted through the tubing to the detector is dependent on the focusing effect of fluid in the lumen of the tubing. A control circuit responsive to the output of the detector interrupts operation of the metering apparatus when the light transmitted through the tubing falls below a predetermined minimum level. The second light detector is positioned at an angle to the light path between the light source and the first detector so as to receive increased light from the light source in the absence of the focusing effect of fluid in the tubing.

Abstract: A liquid presence detector having a light-transmissive chamber for the liquid to be detected. A light emitting diode is positioned outside of the chamber for transmitting light through the chamber and a photosensitive transistor is positioned for receiving the light that has been transmitted through the chamber. The light emitting diode is located at a distance from the chamber that is equal to the focal point of a lens that is created by the chamber and liquid when the liquid is present. The photosensitive transistor output voltage is compared with a reference voltage and an output signal is provided in response to a predetermined difference between the detector output voltage and the reference voltage.

Abstract: In a flow metering apparatus a bubble detector for detecting bubble formation in tubing subject to deformation from internal fluid pressure includes a light source and a light detector. The light detector is positioned on the opposite side of the tubing from the light source such that the light transmitted through the tubing to the detector is dependent on the presence of fluid in the tubing and on the shape of the lumen of the tubing. A control circuit responsive to the output of the detector interrupts operation of the metering apparatus when the light transmitted through the tubing falls below a predetermined minimum level. False interruptions resulting from deformation of the tubing by pressure changes in the fluid are prevented by forming members which engage the wall of the tubing adjacent the light source and light detector.

Abstract: A cassette and controller for accurately controlling fluid flow through an administration set while maintaining a closed fluid system. Inlet and outlet conduits are defined in a body of the cassette and inlet and outlet valves control fluid flow through the respective conduits. A rigid internal cavity of predetermined volume is also defined in the cassette body with an impermeable and flexible diaphragm spanning the cavity. A control conduit communicates with the internal cavity on an opposite side of the diaphragm from the fluid to alternately exert negative and positive pressure on the diaphragm. Negative pressure causes the diaphragm to conform to the shape of the internal cavity when the inlet valve is open to fill the cavity-shaped diaphragm with fluid from the inlet conduit. Positive pressure against the diaphragm expels fluid from the cavity through the outlet conduit when the outlet valve is opened.

Abstract: A system for infusing fluids into the human body includes a peristaltic-type metering apparatus which controls the flow of fluid through a disposable administration set. The metering apparatus includes a control system which allows the volume and rate of flow of the fluid to be infused to be accurately preset by the operator. The control system provides an alarm function in the event of malfunction of the pump or occlusion of the tubing of the administration set, and a minimum pumping rate for maintaining fluid flow through the system after the desired volume of fluid has been infused.

Abstract: A fluorometric analyzer includes a head assembly wherein the photomultiplier tube and excitation lamp of the analyzer are received in respective cavities and a transparent test cell is provided to receive a liquid sample. A first optical passage is provided between the lamp cavity and the test cell, and a second optical passage at right angles to the first optical passage is provided between the test cell and the photomultiplier tube cavity. A manually rotatable shutter assembly concentrically disposed about the test cell includes apertures for allowing light to pass through the optical passages when the shutter is rotated to a first position, and for simultaneously blocking the passage of light through the passageways when the shutter is rotated to a second position. Rotation of the shutter is limited by a first guide pin, and a second guide pin provides a desired degree of friction between the shutter assembly and the head assembly housing.

Abstract: Metering apparatus for metering the flow of fluid through an administration set includes a peristaltic-type metering pump which repeatedly and progressively compresses a section of vinyl tubing of the administration set to provide a desired flow rate. For improved metering accuracy the fluid is maintained under pressure upline and downline of the metering pump to assist the tubing in becoming fully restored following each compression by the pump. In the illustrated embodiment, upline pressure is provided by a peristaltic-type pressure pump which is operated at a controlled rate to maintain a predetermined upline pressure, and downline pressure is provided by a spring-biased plunger which bears against the tubing downline of the metering pump to partially occlude the tubing.

Abstract: A thermoplastic member such as a length of tubing for forming a catheter balloon is positioned on the thermoplastic shaft of a medical device. A length of shrink tubing is placed over each end of the balloon tubing and adjoins a portion of the shaft. Each length of shrink tubing may then be preshrunk to maintain its position. The shaft, balloon tubing, and shrink tubing are then inserted in an apparatus capable of supplying radiant heat in a narrow annular band. The apparatus automatically positions each portion of the shaft and balloon tubing covered by shrink tubing at a location at which it will intercept the narrow annular band of radiant heat. Radiant heat is supplied by the apparatus to cause further shrinkage of the shrink tubing and to seal the balloon tubing onto the shaft. The shrink tubing may be removed to complete the assembly of a balloon catheter. It is preferred that the shrink tubing be tinted so as to enhance the seal formed between the balloon tubing and the shaft.

Abstract: A single-use disposable catheterization package containing the components required for accomplishing a catheterization procedure includes an outer tray and an inner tray. During storage the inner tray is nested within the outer tray and the components required for the catheterization procedure are organized within respective recesses provided on the inner tray. Upon use, the trays are separated and liquid collected as a result of the procedure is received in the outer tray. To prevent spillage, the inner tray is inverted and attached to the outer tray to provide a closed compartment. Rim portions on the inner and outer trays provide a locking leak-resistant engagement between the trays.