Raychem Limited

Other

Paul D Hauptly

Ray F Stewart

John G Lahlouh

Robert S Wasley

Laurence M Welsh

James P Reed

Peter L Brooks

Larry R Reeder

Mauro Bonomi

Michael Masia

Louis M Frank

Thomas W Tolles

Denis I Wales

Devices for detecting and obtaining information about an event, for example the presence of a liquid, which comprise (1) a swellable member which swells upon occurrence of the event and (2) a restraining member which, when the swellable member swells, restricts movement of the swellable member and thus causes the impedance of the device to change. In a preferred embodiment the device comprises two elongate conductors helically wrapped around a support core, a swellable, conductive polymer member surrounding the conductors. Occurrence of an event causes the swellable material to swell and form a conductive bridge between the conductors.

Sensors for detecting and locating fluids

Detection of events, e.g. liquid leaks and other changes in varibles. The event causes two conductors to become electrically connected, and thus creating a system in which the connection point can be located by measuring the potential drop from one end of one of the conductors (called the locating member) to the connection point. Preferably a fixed current flows through the connection, so that the result is independent of the resistance of the connection. The locating member can be a continuous resistive wire, preferably coated with a conductive polymer; such a locating member can form part of a sensor cable in which the elongate components of the circuit are in a wrapped configuration, or part of a cable in which the conductors are separated by a member shaped to prevent capillary action of a liquid from connecting the conductors. Alternatively the locating member comprises a plurality of discrete resistors. Preferably the system is arranged so that the sensitivity of the system is not dependent on the location of the fault and/or is such that only connections within a certain range of resistance will activate the system. The voltage drop is preferably calculated by comparing it to the voltage drop over a resistor of known size. Particular event-sensitive connection means are preferably employed for the detection of hydrocarbons and for the detection of acids.

Elongate sensors comprising conductive polymers, and methods and

Devices for detecting and obtaining information about an event

An electrical sensor and sensor material for detecting the presence of an organic liquid by contact that is not sensitive to the presence of organic vapors from the liquid. The sensor material includes a relatively large concentration of electrically conductive particles within a swellable matrix.

Organic liquid detector

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Fremont, CA, United States of America

Paul D Hauptly