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.