Abstract: An infrared gas analyzer includes an infrared source for emitting infrared energy, a sample cell for gases to be analyzed in the path of infrared energy emitted by the source and an assembly having first and second detectors also in the path of infrared energy and a third detector out of the path of infrared energy, mounted within the assembly and in close thermal proximity to each other and being responsive to impinging infrared energy to produce an electrical response. All detectors are sandwiched between a base and a single window that overlies them. The analyzer further includes a narrow band filter corresponding to an absorption wavelength band for a gas of interest and a narrow band reference filter corresponding to a reference wavelength band. Each of the narrow band filters are positioned outside the assembly and between the assembly and the source in the path of infrared energy.

Abstract: Very generally, the gas analyzer of the invention includes a source of infrared energy, a sample cell for containing an analyte gas mixture positioned in the path of infrared energy, and a monochrometer including a movable diffraction grating for producing a beam of infrared energy wherein the constituent wavelengths are spetrally separated. The device also includes a wide band interference filter for transmitting a predetermined wavelength band spanning the characteristic absorption wavelength of each of a plurality of constituent gases in the analyte gas mixture. A detector positioned to receive radiation passing through the filter produces an electrical response related to the infrared energy impinging thereon. The monochrometer includes provision for moving the diffraction grating to sequentially cause infrared energy of different wavelengths to impinge upon the detector, and for intermittently causing infrared energy directed toward the detector from the source to be blocked by the interference filter.

Abstract: A non-dispersive infrared (NDIR) multi-gas analyzer has an optical element that is positioned with respect to the axis of incident IR radiation such that it passes nearly all of the IR energy within a narrow band pass to one detector and reflects nearly all of the IR energy outside the narrow band pass to another detector. Thus, the optical element simultaneously functions both as a narrow band pass filter and a beam splitter, which transmits nearly all the IR energy within a band pass and reflects nearly all the IR energy outside the band pass. Additionally, the separation of the incoming energy can be achieved without an extended roll off. This allows using a reference transmission band that is very close to the absorption band of the gases of interest. It more specifically allows using a reference transmission band that is located between the absorption bands for hydrocarbons and carbon dioxide in an infrared analyzer that uses beam splitters.

Abstract: An improved sensor support subassembly for a chemical sensor in the testing of gaseous emissions. The sensor support subassembly of the present invention comprises means for slideably engaging a sensor unit with a gas intake manifold block. The sensor unit comprises a cylindrical base which forms the inlet to the sensor. The manifold block comprises a gas intake means, a gas channel and a U-shaped slot for slideably engaging the sensor unit's cylindrical base within the manifold block such that an air-tight passage is formed between the sensor inlet and the gas channel. The sensor support subassembly also provides a sealing means for ensuring an air-tight seal between the sensor unit and the manifold block. This slidable engagement scheme allows the sensor unit to be rotated about the axis of the cylindrical base, which in turn facilitates the use of a card-edge connector for making the electronic connections between the sensor and the sensor testing system power and data lines.

Abstract: An improved apparatus and method for measuring the concentration of carbon dioxide in respiratory gases. The apparatus is a non-dispersive gas analyzer attached in series with the respiratory airway which is universally compatible with any host system. The analyzer includes a housing which supports a sample cell containing the respiratory gases, and which contains an infrared radiation source encased in shock absorbing material, means for directing the radiation into a collimated beam path through the sample cell, means for splitting the beam path and directing it towards a pair of infrared detectors for measuring the amount of absorption of carbon dioxide in the sample cell. The analyzer is further improved by the use of two heating servos, one for regulating the temperature of the sample cell windows in order to inhibit condensation build-up and one for regulating the ambient temperature surrounding the detectors so as to ensure more accurate measurements.

Abstract: A method and system are described for preventing flooding of a gas analyzer of the type wherein a pump conveys gas to be analyzed to a sample cell and a filter separates water from the gas flowing to the pump. The presence of excess liquid in the system is sensed by a pressure transducer which decouples the output of the pump from the sample cell and feeds it back to the filter. This results in an increase in pressure in the filter to prevent excess liquid from flooding the gas analyzer. The pressure is so held until the excess liquid passes from the filter system, after which the system returns to normal operation.

Abstract: A spectrophotometer sample cell is described having a housing defining a frusto-conical chamber with inlet and outlet windows at each end. The inlet window is positioned toward the energy source of the spectrophotometer and the outlet window, which is the larger diameter window, is positioned toward the detector assembly of the spectrophotometer. A single outlet passage is positioned between a pair of inlet passages, the latter being toward respective ends of the chamber. The interior surface of the sample cell is provided with means for preventing a substantial portion of reflected energy impinging on the sample cell walls from reaching the detector. Such means include irregularities, annular walls, and wavelength absorbing colors. A trough is provided in the bottom of the larger end of the frusto-conical chamber for conveying condensate to the outlet passage.

Abstract: This invention is a filter assembly for preparing gases for an exhaust gas analyzer. A single housing includes at least three filter cavities, an inlet passage and two outlet passages. A coarse filter for filtering particlate matter and for condensate condensation is disposed in the first filter cavity. Condensate from the first cavity drains into the second filter cavity which has disposed therein a fine filter for filtering condensate. An outlet passage is connected to the second filter cavity for withdrawal of the condensate. A fine filter for filtering the exhaust gas is disposable in the third filter cavity which is coupled to the first filter cavity. A second outlet passage connects the third filter cavity to a pump for removal of the gas to be analyzed. The present invention thus provides a multiple filter assembly in a single housing with large fine filter area, minimal void volume, minimal interconnections, and convenient access to the individual filters.

Abstract: A pump is described in which a flexible enclosure defines a pump chamber and in which the contents of the pump chamber are expelled by movement of a pair of opposed pusher elements engaged with the enclosure. The pusher elements are displaced by at least one pair of beam springs, each of which is pivotally supported at one end and is engaged with one of the pusher elements at the other end. The ends of the beam springs opposite the pusher elements are pivoted by actuation of symmetrical solenoid armatures, causing each of the springs to be stressed. Relief of the spring stress forces the pusher elements toward each other. De-energization of the solenoid armatures permits the beam springs to pivot back to the original position upon filling of the pump chamber.

Abstract: An infusion system is disclosed for delivering precisely regulated and variable dosages of drugs. The device includes a reservoir for containing the drug, a catheter for delivering drug to the body, and actuating means responsive to a signal applied externally of the body for initiating delivery of a precisely regulated dosage. The actuating means include; a solenoid driven miniature pump which is controlled by an implanted controller and driven by an implanted power source. The implanted controller provides a basal dosage rate which itself may be variable or constant and which may be altered by telemetry signals delivered from outside the body. In addition, the internal device is operable by an external unit which may be set at a different rate from that which the internal or implanted controller is set and which, in addition, provides power for operating the implanted device.

Abstract: A medical infusion system is described employing a pump for conducting fluid or semi-solids from an upstream portion to a downstream portion of the system. The pump includes upstream and downstream conduit means and a removable cassette communicating between the two. The cassette has a window therein and a diaphragm spans the window. The cassette has inlet and outlet openings valvelessly communicating with the pumping chamber or cavity of the cassette. Fluid in the conduit is pumped by restricting and opening the conduit means at upstream and downstream locations, and displacing the contents of the cassette pumping chamber appropriately.

Abstract: Multiple embodiments of an implantable infusion device for delivering precisely regulated dosages of drugs are disclosed, each device including reservoir means for containing the drug, catheter means for delivering the drug to the body and an actuating means which is responsive to a signal applied externally of the body for initiating delivery of a precisely regulated dosage. In one embodiment, the device is implanted subcutaneously to permit actuation by a solenoid driven element responsive to coded telemetry signal applied through the skin. In additional embodiments, the reservoir is pressurized for example, by means of vapor pressure or a mechanical spring, the drug under pressure in the reservoir being released in response to an externally applied signal.

Abstract: A method and apparatus are described for developing a series of synchronizing pulses related to a series of input pulses of variable amplitude above a background noise level. A first signal is developed proportional to the derivative of the rising or falling portion (or both) of each of the input pulses. A second signal is developed related to the first signal and having a decay characteristic such that the amplitude of the second signal becomes equal to the amplitude of the first signal at a threshold point which is proportional to the amplitude of the first signal. The synchronizing pulses are developed related to respective threshold points whereby the phase of the synchronizing signal is not dependent on the amplitude of the input pulses.

Abstract: A gas analyzer of the non-dispersive infrared type is described. An infrared beam passing through a sample cell containing a gas mixture to be analyzed is detected. The resulting electrical signals are processed to produce an output indicating the concentration of the constituents of the gas mixture in the sample cell. The gas analyzer includes provision for temperature stabilizing both a rotary filter wheel and the detector, and for compensating the output of the signal processor for variation in the absorption characteristics of gas with temperature. The emissivity characteristic of the infrared energy source substantially compensates for wavelength dependence of the detector response. The motor drive for the rotary filter wheel is servo-controlled in accordance with synchronizing pulses developed directly from the detector output.

Abstract: A gas analyzer and gas analyzing method are described of the non-dispersive infrared type wherein infrared energy is passed through a sample cell containing an unknown mixture of gas. The infrared energy passing through the cell is received by a detector and an electrical signal is produced representative thereof. A rotary filter wheel positions at least one filter in the path of the infrared energy, resulting in a pulsating detector output. The electrical signal is processed to produce an output indicating the concentration of the constituents of the gas mixture in the sample cell. Synchronization with the processed electrical signal is obtained by deriving synchronizing pulses directly from the electrical signal produced by the detector.

Abstract: A medical infusion system is described employing a pump for conducting fluid or semi-solids from an upstream portion to a downstream portion of the system. The pump includes conduit means defining, in part, a removable cassette having a window therein and a diaphragm spanning the window. The cassette has inlet and outlet openings valvelessly communicating with the pumping chamber or cavity of the cassette. Fluid in the conduit is pumped by restricting and opening the conduit means at three different locations, one of which is before the cassette and one of which is after the cassette and the third of which is at the diaphragm of the cassette.

Abstract: An improved gas analyzer for measuring the presence of one or more gaseous compounds in a gas sample. The gas analyzer has an infrared source stabilized against temperature variations by a radiation loading scheme in combination with a selected source environmental temperature sensitivity to provide a stable source temperature without a conventional temperature controller. A rotating interference filter assembly is disposed in the optical path. This assembly alternately totally blocks radiation, passes radiation in a wave length band which will not be absorbed by a random gas sample, and sequentially passes radiation in one or more additional bands which will be absorbed by one or more gases in the sample cell. The sample cell features a unique enclosed cell with infrared transparent windows which are substantially free of impingement of contaminants of the gas sample thereon. A unique detector provides protection against deterioration from moisture while allowing easy and inexpensive assembly.

Abstract: A compensator designed to be implanted within a living body and connected to an implanted reciprocating blood pump. A housing defines a gas-tight chamber which is separated into front and rear portions by a flexible membrane. A piston attached to the membrane guides the movement of the membrane, and a spring mechanism which links the piston and the housing is designed to maintain substantially constant pressure in the front chamber throughout the discharge and fill strokes of the reciprocating blood pump. Two pivoted, diametrically opposed, compression springs are compressed at rest at the end of the fill stroke and exert a force on the membrane which overcomes the differential pressure acting in the opposite direction when the membrane moves so as to expand the rear chamber volume.

Abstract: A power supply system to operate an implanted electric-powered device such as a blood pump. A secondary coil having a biocompatible covering is implanted to subcutaneously encircle either the abdomen or the thigh at a location close to the exterior skin. The secondary coil is electrically interconnected with an implanted storage battery and the blood pump. A primary coil of overlapping width is worn by the patient at a location radially outward of the secondary coil. An external battery plus an inverter circuit in a pack is attached to a belt having a detachable buckle connector which is conventionally worn about the waist. Efficient magnetic coupling is achieved through the use of two air-core windings of relatively large diameter.

Abstract: A cassette is described for use in an intravenous delivery system having a pump. The volume of a main chamber defined by the cassette body is varied by a membrane in a wall thereof while unidirectional inlet and outlet valves maintain the direction of fluid flow into and out of the main chamber. A prechamber is positioned above the inlet port in order to accumulate air from the upstream portion of the intravenous delivery system in which the cassette is used.