Other

The Boeing Company

Oxigraf, Inc.

Healux, Inc.

Bruce W McCaul

David E Doggett

Eric K Thorson

Thomas Mac Winsemius

Kevin M Smith

Daniel E Hedges

Mark J Holland

Jennifer D Klemisch

Jessica C Pavia

Scott S Rhodes

Thomas Michael Henry

David F Doggett

Clay J Anderson

Jan-Ji Lai

An oxygen analysis system (OAS) for measuring, monitoring and recording oxygen concentration in aircraft fuel tanks. The OAS has a rack support structure installed in an aircraft cabin with a plurality of oxygen analyzer devices mounted in the rack support structure. Each oxygen analyzer device has an oxygen sensor to measure oxygen concentration in gas samples continuously drawn from sample locations in aircraft fuel tanks and at an aircraft NGS ASM exit. The OAS further has a plurality of valves, a supply of calibration gases, a supply of purge and operating gases, and a power distribution assembly, all coupled to the rack support structure. The OAS further has a transport tubing assembly, a plurality of fuel tank gas sampling ports, an NGS ASM exit gas sampling port, a drain manifold assembly, and a data acquisition and recording system having a user interface software to monitor and control the OAS.

Oxygen analysis system and method for measuring, monitoring and recording oxygen concentration in aircraft fuel tanks

Methods and embodiments are described for sampling and measuring oxygen concentrations of flowing samples drawn from the ullage of a chemical or fuel tank and from a source of inerting gas used for purging the tank. The sampled flows are drawn with a venturi pump or a pneumatically driven turbine pump and returned to the ullage of the tank. An optical absorption spectrophotometer is used having a diode laser sensor, and both sensor and the pump can be safely located near to the tank. Control systems and apparatus are disclosed for controlling the oxygen level within the ullage of the tank.

Oxygen sensor for tank safety

An absorption spectroscopy device for determining the concentration of a gas (such as oxygen) in a sample cell includes a neutral density absorber or a quarter wave plate. Laser radiation from a laser diode passes through the neutral density absorber or the quarter wave plate, then passes through the sample cell, and then is incident upon a detector. In some embodiments, the laser diode is driven with a drive current having a stepped periodic waveform.

Gas spectroscopy

The absorption of laser radiation by a gas (such as oxygen and/or carbon dioxide) in human breath is detected on-airway by generating laser radiation using a laser diode, passing the laser radiation through a volume containing human breath multiple times, and detecting the laser radiation which is not absorbed by gases in the volume. To reduce the amount of energy required to control the laser diode, a laser diode is selected which generates laser radiation having a wavelength which is reasonably close to the wavelength of an absorption line of a desired gas when the laser diode is at or near normal body temperature. By passing the laser radiation through the sample gas multiple times, a longer path through the sample gas is provided for absorption thereby allowing the concentration of a gas having weak absorption lines (such as oxygen) to be determined using on-airway absorption detection. A two piece on-airway spectroscopy device is disclosed having a disposable mouthpiece portion and a reusable sensor assembly portion having a laser diode and a photodetector.

A laser diode lens assembly wherein a lens or lens assembly is immovably adhered to a housing of a laser diode package. The laser diode package may be a metal can style package having a substantially transparent window portion through which laser radiation is emitted when a laser diode inside the housing is supplied with current. The lens or lens assembly may be immovably fixed to an outer surface of this window so that a central axis of a beam of laser radiation emerging from the lens or lens assembly has a desired spatial relationship with a reference surface of the housing. An adhesive such as an epoxy adhesive which is cured under exposure to ultraviolet radiation may be used to freeze the lens or lens assembly in place to the window when the lens is correctly positioned.

Laser diode/lens assembly

A spectroscopy device comprises a laser diode/lens assembly driven by a periodic stepped laser diode drive current. Each period of the stepped laser diode drive current has a plurality of constant current intervals: a left baseline interval, a left skirt interval, a peak interval, a right skirt interval, and a right baseline interval. The left and right skirt constant current intervals are used to lock the laser radiation emitted during the peak interval onto a preselected absorption line. The left and right skirt intervals are also used to obtain a value indicative of line width. The peak interval is used to obtain a value indicative of peak absorbance. Multiplying the peak and line width values together yields a value indicative of a gas concentration which is substantially independent of foreign gas line-broadening effects.

A spectroscopy device comprises a laser diode/lens assembly driven by a periodic stepped laser diode drive current. Each period of the stepped laser diode drive current has a plurality of constant current intervals: a left baseline interval, a left skirt interval, a peak interval, a right skirt interval, and a right baseline interval. The left and right skirt constant current intervals are used to lock the laser radiation emitted from the laser diode onto a preselected absorption line. The left and right baseline constant current intervals are used to subtract baseline absorption measurements from peak constant current interval absorption measurements. A high frequency common mode noise rejection circuit rejects noise common to a monitor radiation detector and a radiation detector which detects radiation passing through a sample cell. A serial line locking cell is provided to allow locking when little or no absorbing material is present in the sample cell. A heated sample cell is provided to allow for the measurement of oxygen concentration in human breath. The pressure and temperature of the gas in the sample cell are detected to account for pressure and temperature dependencies of the absorption measurement. Techniques are disclosed for minimizing the effects of unwanted reflections off various surfaces of a spectroscopy device which otherwise would reflect back into the laser diode.

Carboxyhydroxyporphin compounds such as hematoporphyrin exhibit instability upon warming. However, if this warming is extended and carried out in solution in the presence of a buffer so as to constitute a moderate temperature heat-treatment, a new composition of matter results which contains as much at 95% or more of an ester-linked oligomeric porphin-based material which is exceedingly storage-stable. This composition has superior activity as a photoimaging and photodynamic therapy agent. This process and the products it produces are disclosed. The oligomer products so formed can be formulated into pharmaceutical compositions for use in neoplastic tissue photoimaging and in photodynamic therapy of neoplastic tissues.

Growing community of inventors

Palo Alto, CA, United States of America

Bruce W McCaul