Abstract:
A flame quality analyser for analysing one or more properties of a flame from a burner comprises a fibre optic array (32,33) including a plurality of optical fibres each having a light-receiving end lying in a line and facing the flame. The line may extend parallel to the flame and burner axis (array 32) or may extend perpendicular to that axis (array 33). The light received by the fibre optic array (32,33) is provided as a sheet of light to a monochromator which spreads the light into its component wavelengths. A pair of spaced apart arrays of light detectors is then utilised to measure the light at two discrete wavelengths. This detection produces signals that can be analysed to generate temperature and particles distribution values for the flame across its length or width.
Abstract:
A spectrophotometer wherein the diffraction grating is driven directly by a pulse motor and the wavelength of the monochromatic light used for measurement is calculated by a data processor from the amount of rotation of the pulse motor. The data processor is provided with an Input unit for setting a parameter corresponding to the difference between the nominal and actual grating constants of the diffraction grating and so arranged as to calculate the wavelength in accordance with the nominal grating constant having been modified with the parameter set through the Input unit.
Abstract:
Photometer having a variable wavelength comprising at least one light source, a monochromator having an adjustable wavelength, a sample position and a detector which detects the substantially monochromatic radiation obtained from the light source via the monochromator and the sample position. Furthermore, the photometer comprises a rotatable disc located in the light path and provided with angle position indication means by means of which it is possible to determine from the instant values of the detector signal the segment of the disc that has affected the radiation giving rise to the instant values in question.
Abstract:
A beam of radiation is directed into a liquid sample cell containing a sample to be analyzed in solution. The illumination emanating from the sample cell as a result of the beam of radiation from the radiation source is diffracted into a polychromatic spacially divergent beam and directed to a linear array of photovoltaic photodetectors with different spectral segments of the beam being intercepted by different photodetectors of the array. The signals from the photodetectors are separately and substantially simultaneously sampled and held to thereby obtain data usable for a high-accuracy wide-spectrum chromatogram.
Abstract:
A spectrophotometer includes means for ensuring that the active area of a detector is always filled regardless of the resolution aperture setting of the instrument.
Abstract:
Light from a light source is dispersed by a grating. Two multichannel light detectors are arranged for detecting the dispersed light. One light detector detects the first order of interference and the other light detector detects the second order of interference in overlapping wavelength ranges. The outputs of the two light detectors are averaged for improving the S/N ratio, particularly in wavelength ranges in which the light intensity of the light source is low.
Abstract:
A system for maintaining the wavelength scale calibration of diffraction grating based spectrometers and monochromators is disclosed. The system utilizes the approximately fixed angular relationship between diffracted and undiffracted light emanating from the diffraction grating to maintain the calibration of an instrument. One or more photodetectors are used to measure shifts in an undiffracted image due to mechanical misalignments that cause errors in the instrument's wavelength scale. Once direction and degree of shift known, the instrument is recalibrated either by adjusting various mechanical and/or optical structures within the instrument to shift the undiffracted images by an amount equal to, but in a direction opposite the measured shift so that the diffracted light is likeweise shifted, or by relabeling the wavelength scale outputs by an amount derived from the measured shift.
Abstract:
Method and apparatus for simultaneously recording multiple Fourier Transform Infrared (FT-IR) signals. The analog signals from an interferometer are coupled to switching means which is operable in response to a first control signal for synchronizing the operation of the interferometer and a second control signal for defining data acquisition intervals to direct the sampled data of the analog input signals over a circuit path including Sample and Hold and Analog to Digital Conversion circuits to a processor for storing the digital data corresponding to the analog input signals. The switching means is operated so that samples of the analog input signals are taken in sequence and stored in sequential storage locations in interleaved fashion. The processor is operable under program control to access the digital data so that all data samples for the same input signals are separated to produce an interferogram for each of the input signals. These interferograms can then be Fourier transformed to produce spectra in the usual manner.