Abstract: A measurement device and method for measuring tension in an optical fiber or wire. The measurement device includes a device for producing a vibration surge in the optical fiber or wire which vibrates at a certain, pre-selected frequency and advances as a linearly polarized wave. An optical location-sensitive detector measures the advancing speed (v) of the wave. An illuminator device illuminates the optical fiber or wire so that a shadow or an image of the vibrating fiber or wire is cast onto the indictor whereby the tension (T) of the optical fiber or wire is calculated from the equation T=v.sup.2 .multidot.M, when M is the fiber mass per unit of length of the optical fiber or wire. The indicator device measures the time at which a departing wave surge passes by the indicator and the time at which an arriving wave surge reflected from a subsequent coating vat, or other wave reflector, passes by the indicator.

Abstract: A detector indicating ice formation on the wing of an aircraft or any planear surface, based on a thread-like or a tape-like transducer, through which an ultrasonic signal is transmitted at one end. The attenuation of the signal having passed through the thread is measured with a receiver at the opposite end while the thread is simultaneously being heated such that ice that may surround it melts again, the attenuation thus resuming its initial level.

Abstract: The invention relates to an on-line tension meter for an optic fiber. The tensile stress of a bare optic fiber is measured without contacting the optic fiber as the optic fiber is drawn in a draw machine. A loudspeaker causes a wire wave to be formed in the fiber. The fiber tension is then measured by the advancing speed of the wire wave. The speed is measured by means of two location-sensitive electro-optic indicators or cameras, the distance therebetween being known.

Abstract: A theremometer or temperature alarm device making use of fibre optics. The measuring instrument has a fibre-optic light transmitter (1), which sends out light along an optic fibre (2) to a measuring head (5) on the end of the transmitting fibre (2), and a fibre-optic receiver (3), which is connected with an optic fibre (4) to the same measuring head (5). The measuring head (15) is a cell or hollow enclosure (6) which has been filled with a light-scattering substance (7) of the kind which below a certain threshold temperature scatters the incident light from the transmitting fibre (2) back to the receiving fibre (4) but above the threshold temperature characteristic for the substance (7) loses its light scattering capacity so that the light coming from the transmitting fibre (2) is no longer scattered to the receiving fibre (4).

Abstract: A liquid detector utilizing fiber optics, by which the presence of oils and various solvents can be detected. The detector is internally safe because the optical fiber is an insulator and may therefore be used to monitor liquids involving fire or explosive hazards. The detector may be used to detect leakage when storing oils and solvents, because it reacts most rapidly with these liquids. The detector makes use of capillarity of a sensing pick-up thereof, the optical reflection coefficient of the pick-up material changing as the pick-up material comes into contact with the liquid to be detected.