Abstract:
A compact infrared gas analyzer capable of reducing the quantity of heat generated from a radiation source and the effects of temperature on samples is provided. A shutter is provided between the radiation source and the sample cell and/or between the sample cell and a detector with the shutter in a closed position. The shutter is opened and closed during measurement. A resistor comprising a resistance element made of one of RuO.sub.2, W, SnO.sub.2, FeCrAlY, Pt, Pt-Rh and Pt-Pd, formed on an AlN substrate, may be used as the radiation source, with the radiation source and the shutter being interrelatedly controlled.
Abstract:
The fire detector includes a carbon dioxide sensor and a microcomputer. When the rate of increase of the concentration of carbon dioxide at the sensor exceeds a threshold, an alarm is produced. The threshold is set at one of three possible levels by the microcomputer in response to the state of the atmosphere at the sensor as determined by the microcomputer based on several variables that are derived from the sensed concentration of carbon dioxide. The derived variables include the average concentration of carbon dioxide, the average rate of change of carbon dioxide concentration, the monotonicity of the increase or decrease of the carbon dioxide concentration and the range of concentrations sensed in each cycle of operation. The threshold setting is determined every ten seconds. In this way, the setting of the rate threshold is responsive to variations in the carbon dioxide level at the sensor that are caused by entities other than a fire, such as the presence or absence of people in a closed room.
Abstract:
An apparatus for measuring the combustion effluent of a fossil-fired system with high accuracy as required for the determination of fuel flow rate and boiler efficiency.
Abstract:
A miniature source of modulated infra-red energy comprises a very thin heated wire strip (11) of low mass, mounted in a tensioned state by means of two resilient members (18), and a reflector (15) positioned behind the wire (11) so as to enhance the radiated energy. The source is hermetically sealed in an inert atmosphere with a cap (20). The cap (20) has an aperture (16) through which the energy emerges, this is sealed either with a window or a filter (17) if a specific wavelength is desired.
Abstract:
A diffusion-type gas sample chamber for use in a gas analyzer consists of an elongated hollow tube having an inwardly-facing specularly-reflective surface that permits the tube to function also as a light pipe for transmitting radiation from a source to a detector through the sample gas. A number of filtering apertures in the wall of the otherwise non-porous hollow tube permit the sample gas to enter and exit freely under ambient pressure. Particles of smoke and dust of a size greater than 0.1 micron are kept out of the chamber by use of a semi-permeable membrane that spans the apertures in the hollow tube. Condensation of the sample gas components is prevented by heating the sample chamber electrically to a temperature above the dew point of the component of concern.
Abstract:
A non-dispersive infrared gas analyzer of the type typically used to measure concentrations of gases in medical and industrial applications has no moving parts and employs two or more miniature infrared sources ("microsources") which are electrical current-modulated to produce modulated infrared radiation for synchronous detection. The microsources are operated at different frequencies. The frequency-multiplexed detector signal is demodulated and ratioed to yield an output which is correlated to the gas concentration in the sampler chamber.
Abstract:
Oil sensor that comprises a holder (2) to which an elongated crystal (3) is fastened that is transparent to infrared light and with a refractive index greater than the refractive index of the oil (5) to be examined, whereby a light source (7) is provided in the holder (2) at a first end (4A) of the elongated crystal (3) for transmitting light in the infrared spectrum in the elongated crystal (3), and detection means (8) at a second end (4B) of the elongated crystal (3) for measuring the intensity of the light, which during the passage through the elongated crystal (3) undergoes total reflection at a boundary plane (9) at least four times in succession in a contact zone (10) where the elongated crystal (3) comes into contact with the oil (5) to be examined, characterised in that the oil sensor (1) is further provided with at least one temperature sensor (11) to determine the temperature of at least one of the components of the oil sensor (1), and that the part of the light source (7) that can emit light can be heated to a temperature of more than 400°C.
Abstract:
Appareil éthylomètre portable pour mesurer le taux de gaz partiel exhalé dans le fluide d'haleine en respectant un écart type inférieur à 0,007 mg/L pour toute concentration inférieure à 0,400 mg/L, un écart-type relatif inférieur à 1,75 % pour toute concentration supérieure ou égale à 0,400 mg/L et inférieure ou égale à 2,000 mg/L et un écart-type relatif inférieur à 6 % pour toute concentration supérieure à 2,000 mg/L, ce dispositif incluant une unité d'alimentation rechargeable, un dispositif d'émission d'un rayonnement infrarouge puisé, un récepteur infrarouge et une cuve de mesure dans laquelle circule le fluide, caractérisé en ce que, le dispositif d'émission comprenant un élément chauffant dont la puissance est comprise entre 60 mW et 130 mW, la cuve de mesure comprend un tube métallique d'un diamètre intérieur compris entre 5 et 12 mm, d'une longueur comprise entre 140 et 220 mm et dont la surface intérieure est polie et revêtue d'un dépôt réfléchissant au moins le rayonnement infrarouge de longueurs d'ondes comprises dans l'intervalle [9,10μm] et, à chaque extrémité du tube, un embout comprenant une section conique destinée à être placée dans l'axe du tube et dont l'angle d'ouverture est compris entre 8° et 30°, le dispositif d'émission infrarouge étant placé sur l'axe longitudinal du tube au niveau d'un des embouts, le récepteur étant placé sur l'axe longitudinal du tube au niveau de l'autre embout, le tube étant en outre muni de moyens de chauffage aptes à porter le tube à une température supérieure à 39°C.
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 are described for driving a modulated radiation source (which can be, for example, an infrared light source). The method affects the power driving a light source in such as way so as to minimize the warm-up time of the source. The apparatus permits feedback control of a light source to specified powers or temperatures. Disclosed embodiments can improve source performance and lifetime and decrease the operating costs of the source.