Abstract: A method for controlling or monitoring firing systems and for monitoring buildings having gas burners using spectroscopy, provides at least one wavelength-tunable monochromatic light source. An absorption spectrum of a measuring gas is received with at least one photodetector in an absorption path with spectral tuning of the light source, and the concentration of target gases carbon monoxide (CO) and methane (CH4) can be determined simultaneously during tuning of the light source. A device for carrying out the method includes a monochromatic laser diode, in particular a VCSEL, an absorption path in the exhaust gas region or a space endangered by leakage, a photodetector for receiving light passed through the absorption path, and an evaluation unit for determining the concentration of target gases based on the absorption spectrum covered during the laser or laser diode tuning. The method and device are applied in laser-optical gas sensors in gas firing systems.

Abstract: A method for monitoring a combustion process in the infrared wavelength range includes using a laser, which transmits a laser light beam along a measurement path in a certain wavelength range, which is selected in such a way that a gas therein to be detected in the combustion process has an absorption line, and that the emission wavelength of the laser detects the absorption line of the gas to be detected upon the tuning in the selected wavelength range. The concentration of the gas is determined as a function of the absorbed energy of the laser light beam. The intensity of the laser light beam is detected and is analyzed in order to determine the existence of a flame in the combustion process, and/or the quality of the flame.

Abstract: A method and apparatus for testing an elongate product for faults and defects, which comprises a rotatable testing head which permits the elongate product to be passed coaxially therethrough and which mounts a pair of testing probes so as to permit adjustment of their operating diameter. In order to automatically adjust the positions of the probes to accommodate elongate products of different sizes, there is provided an external adjustment unit, which stops the testing head in a predetermined angular position. The adjustment unit contains an external adjustment drive and when the rotation of the testing head has stopped, the external adjustment drive is advanced into operative engagement with the adjustable mounting of the testing probes.

Abstract: The described rotating head effects A.C. field stray flux defect testing process using a rotating magnet yoke for high magnetizing field strength. The unit is compact and replaces a great number of conventional stationary devices in which the test article must be moved along a helical line past the magnet yoke. A speed of the rotating head of 900 revolutions per minute with an effective width of the probe support of 10 cm, achieves a testing speed of approximately 1.5 m/sec. This high testing speed makes the use of A.C. field stray flux testing at high magnetizing field strength possible from the economical point of view.

Abstract: A representative reading for the concentration of a suspension of luminous and magnetizable particles is provided in every case, even when luminous but non-magnetizable particles are also present. That is, the presence of non-magnetizable luminous particles in the suspension have no effect on the determination. A rotating wheel-like member has its lowermost portions immersed in a supply of the magnetic particle suspension in a fluid carrier. The circumferential periphery includes a permanent magnet having a gap extending continuously around the periphery and covered over by a plastic rim. As the wheel-like member rotates, the magnetic particle suspension forms a bead along the magnet gap. Ultra violet radiation directed onto the bead causes the magnetic particles to fluoresce and the degree of fluorescence is measured by photosensitive means.