Abstract:
An electrically modulated light source is provided. The electrically modulated light source comprises a carbon nanotube film structure. The electrically modulated light source heats up to a highest temperature and emits thermal radiation in less than 10 milliseconds after a voltage is applied, and the electrically modulated light source cools down to an initial temperature of the electrically modulated light source in less than 10 milliseconds after the voltage is removed. An modulation frequency of the electrically modulated light source is greater than or equal to 150 KHz. A non-dispersive infrared spectrum detection system used the electrically modulated light source, and a method for detecting gas used the electrically modulated light source are also provided.
Abstract:
Infrared detection device comprising a gas detection device comprising a resistive layer, a first portion of which is able to emit infrared radiation able to be absorbed by the gas to be detected, and a second portion of which is thermally coupled to a first element for the thermoresistive transduction of the infrared radiation; a substrate comprising an electronic circuit for controlling and reading the gas detection device; portions of electrically conductive material electrically connecting the first portion and the first thermoresistive transduction element to the electronic circuit, and providing mechanical holding of the first and second portions opposite the substrate so that a distance between the first portion and the substrate is substantially equal to a distance between the second portion and the substrate.
Abstract:
A method and device for measuring the soot load in the exhaust gas systems of diesel engines using a sensor which is mounted downstream of a particulate filter and comprises a sensor element, to measure the operability of the particulate filter. According to the method, the soot load of the sensor element is measured resistively or capacitively using electrodes. The measuring voltage of the sensor element is controlled depending on at least one actual operating parameter of the diesel engine.
Abstract:
The present invention relates to a system for the optical detection of light from analytical samples, the system comprising an analytical instrument comprising an optical detection unit and a sample block unit for receiving a plurality of analytical samples, the system further comprising a calibration device for calibrating the optical detection unit of the analytical instrument, wherein the calibration device comprises a substrate and at least one electrically powered reference light source coupled to the substrate, said at least one reference light source emitting light being detected by the optical detection unit.
Abstract:
Thermally tunable optical sensors are used in sampling tools for analysis of samples from a wellbore. The thermally tunable optical sensors generate a series passbands of wavelength emissions and detect attenuation in a signal thereof. The attenuation detected is processed and used to determine aspects of the samples. Analysis may be completed remotely (outside of the wellbore), within the wellbore (during drilling or otherwise), or as a part of another process such as fluid management, transport and refinement.
Abstract:
A method and apparatus for measuring blood gas concentrations and partial pressures, in real time, using a pneumatic detector to indicate partial pressure variations in the blood gas.
Abstract:
An emitting source capable of radiating substantial energy in the near infrared spectrum and suitable for use in non-dispersive infrared gas analyzers or other devices is described. Operation can be steady state (DC) or pulsed at high frequency with excellent modulation characteristics. The device consists of a tungsten filament mounted across the pins of a small transistor outline header and centered at the focal point of a parabolic or other shaped reflector. The header assembly is enclosed by a resistance-welded cap and window assembly having a specially sealed sapphire or other suitable IR transmissive window. Fundamental to the operation of the inventive IR emitter is the incorporation of a getter within the header package configured to prevent oxidation degradation of the tungsten filament. An inert gas backfill limits filament evaporation and further extends apparatus lifetime.
Abstract:
A compact low-cost fire detector responds quickly by detecting an increase in the concentration of carbon dioxide gas in the ambient air. The detector also calculates the rate of build-up of carbon dioxide. The detector avoids the use of moving parts by employing a differential temperature black body source of infrared radiation in conjunction with a dual pass band filter. One of the pass bands is located at the 4.26 micron absorption band of carbon dioxide gas and the other pass band is located at 2.20 microns at which none of the atmospheric gases has an absorption band. The latter channel serves as a reference and renders the detector immune to false alarms caused by dust or smoke particles in the air or due to deterioration of certain components. The fire detector makes use of a sample chamber that consists of a serpentine passage in a block of material, the walls of the serpentine passsage being highly reflective so as to act as a light pipe.
Abstract:
Gas analyzers of the non-dispersive infrared radiation type which are designed to measure the concentration of one gas in a mixture of gases containing that gas. A novel, electrically modulated, stable, thick film infrared radiation emitter is employed to emit a beam of collimated, focused energy; and two electrically biased detectors are preferably used so that a ratioed, error eliminating output signal can be supplied to the failsafe, signal processing circuitry of the analyzer. The latter, and a conventional analog-to-digital convertor, supply information to a microcomputer which: (1) turns the infrared radiation emitter on and off; (2) controls a heater which keeps the infrared radiation detectors at a constant, precise temperature; and (3) controls displays of a variety of information concerning the gas being measured and the status of the gas analyzer. The microcomputer also accepts ambient temperature, barometric pressure, and other compensation factors. Typically, a disposable airway adapter will be included in the gas analyzer to confine the mixture of gases being analyzed to a path having a transverse dimension of precise and specific length and to provide an optical path across that stream of gases between the infrared radiation emitter and the infrared radiation detectors. The emitter and detectors are incorporated in a transducer head which can be detachably fixed to the airway adapter.
Abstract:
A light source and a method for its use in an optical sensor are provided, the light source including a resistively heated element. The light source includes a power circuit configured to provide a pulse width modulated voltage to the resistively heated element, the pulse width modulated voltage including: a duty cycle with a first voltage; and a pulse period including a period with a second voltage, wherein: the duty cycle, the first voltage, and the pulse period are selected so that the resistively heated element is heated to a first temperature; and the first temperature is selected to emit black body radiation in a continuum spectral range. Also provided is an optical sensor for determining a chemical composition including a light source as above.