Abstract: The present invention describes an apparatus and method for determining the energy expenditure of a subject by indirect calorimetry where respiratory gases O2 and CO2 are captured in a tent mask coupled through a pneumotach flow meter to a vacuum inlet of a blower fan whose speed is controlled by a computer running a program that ensures that the bias flow being drawn through the mask always exceeds the subject's peak expiratory flow. VO2 and VCO2 and flow values are measured on a breath-by-breath basis and used in arriving at a bias flow adjustment voltage to be applied to the blower fan for adjusting its speed.

Abstract: The present invention describes an apparatus and method for determining the energy expenditure of a subject by indirect calorimetry where respiratory gases O2 and CO2 are captured in a tent mask coupled through a pneumotach flow meter to a vacuum inlet of a blower fan whose speed is controlled by a computer running a program that ensures that the bias flow being drawn through the mask always exceeds the subject's peak expiratory flow. VO2 and VCO2 and flow values are measured on a breath-by-breath basis and used in arriving at a bias flow adjustment voltage to be applied to the blower fan for adjusting its speed.

Abstract: A wireless tire pressure sensing system for an aircraft comprises: dual resonant circuits mounted to a wheel of the aircraft, each resonant circuit comprising: a variable capacitance sensor and a wire loop of a predetermined inductance coupled thereto, one capacitance sensor for monitoring the pressure of a tire mounted to the wheel, and the other capacitance sensor operative as a reference to the one capacitance sensor; an interrogating circuit magnetically coupleable to the dual resonant circuits and operative to induce magnetically a variable frequency current in the dual resonant circuits, the one resonant circuit responding to the induced current with an E-field signal at a first resonant frequency commensurate with the capacitance of the one sensor, and the other resonant circuit responding to the induced current with an E-field signal at a second resonant frequency commensurate with the capacitance of the other sensor; a receiving circuit E-field coupleable to the dual resonant circuits and operative t

Abstract: A wireless tire pressure sensing system for an aircraft comprises: dual resonant circuits mounted to a wheel of the aircraft, each resonant circuit comprising: a variable capacitance sensor and a wire loop of a predetermined inductance coupled thereto, one capacitance sensor for monitoring the pressure of a tire mounted to the wheel, and the other capacitance sensor operative as a reference to the one capacitance sensor; an interrogating circuit magnetically coupleable to the dual resonant circuits and operative to induce magnetically a variable frequency current in the dual resonant circuits, the one resonant circuit responding to the induced current with an E-field signal at a first resonant frequency commensurate with the capacitance of the one sensor, and the other resonant circuit responding to the induced current with an E-field signal at a second resonant frequency commensurate with the capacitance of the other sensor; a receiving circuit E-field coupleable to the dual resonant circuits and operative t

Abstract: A wireless tire pressure sensing system for an aircraft comprises: dual resonant circuits mounted to a wheel of the aircraft, each resonant circuit comprising: a variable capacitance sensor and a wire loop of a predetermined inductance coupled thereto, one capacitance sensor for monitoring the pressure of a tire mounted to the wheel, and the other capacitance sensor operative as a reference to the one capacitance sensor; an interrogating circuit magnetically coupleable to the dual resonant circuits and operative to induce magnetically a variable frequency current in the dual resonant circuits, the one resonant circuit responding to the induced current with an E-field signal at a first resonant frequency commensurate with the capacitance of the one sensor, and the other resonant circuit responding to the induced current with an E-field signal at a second resonant frequency commensurate with the capacitance of the other sensor; a receiving circuit E-field coupleable to the dual resonant circuits and operative t

Abstract: A wireless tire pressure sensing system for an aircraft comprises: dual resonant circuits mounted to a wheel of the aircraft, each resonant circuit comprising: a variable capacitance sensor and a wire loop of a predetermined inductance coupled thereto, one capacitance sensor for monitoring the pressure of a tire mounted to the wheel, and the other capacitance sensor operative as a reference to the one capacitance sensor; an interrogating circuit magnetically coupleable to the dual resonant circuits and operative to induce magnetically a variable frequency current in the dual resonant circuits, the one resonant circuit responding to the induced current with an E-field signal at a first resonant frequency commensurate with the capacitance of the one sensor, and the other resonant circuit responding to the induced current with an E-field signal at a second resonant frequency commensurate with the capacitance of the other sensor; a receiving circuit E-field coupleable to the dual resonant circuits and operative t

Abstract: A disposable pneumotachograph flowmeter comprises first and second tubular mouthpiece members which, when juxtaposed relative to one another, sandwich a fabric screen made from a hydrophobic material therebetween. The screen may comprise a woven fabric formed from expanded PTFE fibers or, alternatively, may be a non-woven mat of polyester fibers. Because of the properties of the screen material, it does not become clogged and occluded with moisture particles during use.

Abstract: A drying sample line for coupling a patient's expiratory gases to a gas analyzer consists of first and second concentrically disposed tubes where the innermost tube is fabricated from Nafion plastic. The expiratory gas is drawn through the lumen of the Nafion inner tube and, simultaneously, dried air is made to pass through the lumen of the outer tube in a counterflow direction relative to the expiratory gases. Because of the properties of the Nafion plastic, water vapor (moisture) contained in the expiratory gas being coupled to the analyzer passes through the wall of the Nafion tube and into the dried air stream. In this fashion, the water vapor is removed from the expiratory gas mixture being applied to the analyzer.

Abstract: A flow meter system having a disposable mouthpiece including symmetrically disposed pitot tubes for measuring the velocity of the respiratory gases flowing through the mouthpiece and an electronic module including sensitive pressure transducers coupled to the mouthpiece and operative over a wide dynamic range provides input signals to a signal processing network for converting the pressure readings to flow information useful in cardiopulmonary performance analyzing equipment.

Abstract: A zirconia oxygen sensor is disclosed which is especially designed for sensing respiratory gases on a breath-by-breath basis. In order to obtain a sufficiently high response time necessary for breath-by-breath gas analysis, a commercially-available zirconia ceramic element is dimensionally tailored to cooperate with a manifold member such that the volume of the gas being analyzed is extremely small, yet uniformly distributed over an internal surface of the zirconia cell. Cooperating with the zirconia cell and the manifold are a set of spring contacts which perform the dual function of providing an electrical terminal and acting as a gas-type seal when the manifold is compressed against the end of the cell.