Abstract: A sensing cable designed for distributed pressure sensing includes one or more optical fibres which have a continuous weak fiber Bragg grating permanently written inside a core of the optical fiber. The sensing cable is configured so that pressure applied to the sensing cable changes birefringence in the one or more optical fibers.

Abstract: A sensing cable including one or more optical fibers and a coating which is provided on the one or more optical fibers. The coating is configured so that pressure applied to the sensing cable, along one or more axes, induces less lateral compression on the one or more optical fibers than pressure applied to the sensing cable along one or more other axes so as to change birefringence in the one or more optical fibers.

Abstract: A photoacoustic device for analysis of fluids. The device is made up of (A) a source of a pulsating beam of light, preferably of the chopper type, and (B) an enclosure, preferably an elongated structure having a generally cylindrical, e.g. essentially tubular shape; and containing and holding--in sonic insulation--at least one reference chamber and at least one measuring chamber in an essentially linear or serial arrangement in a common cell within the enclosure, preferably in an essentially coaxial arrangement; the enclosure and the common cell provide a path P for the pulsating beam of light through the reference chamber and through the measuring chamber. For most purposes, it is preferred that the light beam pass first through the reference chamber and subsequently into the measuring chamber. Optionally, a second reference chamber is arranged at the end of the measuring chamber and a second measuring chamber may follow.

Abstract: A probe for measuring the concentration of an alcohol, such as ethanol, in a liquid, such as water. The probe according to the invention has a membrane that is permeable for vapors of the alcohol but substantially impermeable for the liquid; a measuring chamber having an open end closed against the liquid by the membrane is provided and has an inlet and an outlet; a pump or other pressure means serves to feed a purge gas, such as air, via the inlet into and out of the measuring chamber; a valve is provided near the inlet for controlled passage of the purge gas through the chamber; a suitably dimensioned detector including a pellistor or a gas-sensitive resistor is arranged in the measuring chamber for quantitative detection of the alcohol and for generating an electrical signal in proportion with the detection.

Abstract: The gas detection apparatus comprises a holder for the temporary fixation of an associated package and which contains a contact surface. A hollow needle having a tip serves to penetrate a portion of the package which is freely exposed at the region of the contact surface. This hollow needle comprises at least two channels. An element serves for the essentially gas-tight connection of the hollow needle tip with the contact surface or the part of the package freely exposed therein. A component is connected by a connection line with one channel of the hollow needle. A suitable membrane-enclosed sensor, such as an amperometric sensor defining a sensor surface formed by a semi-permeable membrane, is preferably suspendingly arranged in the compartment. A preferably closable flushing or purging gas line communicates with the connection line and allows flushing the compartment, the connection line and the one channel.