Apparatus for the detection of leakage current in a system includes a power supply and conductors from the supply for supplying power to a load connected to the system. There is an interrupter connected in the system and to a ground point such that a ground leakage current in the system has a closed circuit. Activation of the interrupter about every 12 seconds effectively generates a pulse interrupted ground fault signal. Such signal is detected by a magnetic sensor located relative to a multi-f...

A detection device comprising a longitudinally extending hollow body (7) having a light input position (11) located transversely between the ends thereof, one end comprising an output or viewing window end (10) and the other end comprising an output/input window end (b 12). Light transmissive fibres are provided to connect between the light input position (11) and the output/input window end (12) and between such output/input window end (12) and the viewing window end (10). Means (17, 18) are pr...

A fridge freezer is provided on a cold surface contactable by humid ambient air with a sensor that is able to activate a heater or an alarm etc., on the appearance of condensation.

An apparatus for detecting the occurrence of an event, e.g. the presence of a liquid leak. The apparatus includes an elongate flexible core consisting of elongate elements which are twisted together. The elongate elements comprise first and second sensing members, which each have an electrically conductive outer surface and are physically separated from one another, and at least two elongate insulating members. These elongate elements are covered by a flexible braid which exerts a compressive fo...

A solution of various benzaldehyde derivatives dissolved in suitable solvents are used in impinger sampling or as a coating on substrates to provide passive, real-time visual colorimetric indication of the presence of hydrazine and its derivatives.

Detection and quantitative measurement of the radioactive isotope of .sup.222 Rn, as encountered in air in habitats is accomplished in a passive detection system in which the radon at the test site is adsorbed into an adsorbent, e.g. activated charcoal, held in a vial made especially for liquid scintillation counting, and the radon is subsequently desorbed into a liquid scintillation desorbent placed in the same vial and the counting of the radon activity in the vial is accomplished by liquid sc...

The invention relates to a method for optically sensing the surrounding area of a vehicle using at least one optoelectronic emitting/receiving device that is mounted on the vehicle. According to the method, a monitoring area located in the field of vision of the emitting/receiving device is scanned and, in addition to the monitoring area, a region of particular interest is scanned by using at least one radiation deflecting device, which is located in the field of vision of the emitting/receiving...

A detection device for detecting a body entering a predetermined range has a transmission means for periodically radiating a pulse-like transmission signal by way of an electromagnetic wave to which a band restriction has been applied, a first reception means and a second reception means, and a judgment means. Each of the reception means performs receiving, as a reception signal, the electromagnetic wave reflected by the body, periodic sampling of the reception signal after a predetermined delay...

There is provided a mechanism for error detection comprising: detecting the symmetry of error distributions over adjacent time intervals and muting of a radiotelephone in response to detected loss of substantial symmetry, unless errors are attributable to valid alternative detections. It is further characterized by: detecting the symmetry of error distributions over adjacent time intervals and muting a radiotelephone as a corrective response to detected consequential asymmetry or loss of substan...

Methods of and apparatus for detecting the leakage of fluids from containment vessels. The tank is surrounded by or lined with a generally fluidtight envelope, and a vacuum is applied to hold the envelope against the tank and thereby control and limit to a very small volume the space between the primary containment, be it the vessel or liner, and the envelope. Fluids escaping from the containment vessel collect in that space. Collected fluids are evacuated; and fluid withdrawal information is pr...