Raychem Limited

Underground Systems, Inc.

David C Bliven

Julian Sean Mullaney

Gerald L Shimirak

Anthony Vranicar

Philip B Vail

John Seymour Mattis

Steven S Sunshine

A method and apparatus for continuously monitoring and measuring the concentration of gases in a gas-containing liquid such as a transformer oil. The method and apparatus employ a passive gas extraction technique which comprises a high performance membrane material to extract dissolved gases from the oil, and an IR-based sensor to detect gases present. The passive gas extractor extracts dissolved gas from the gas-containing liquid, there being a known relationship between the concentration of a constituent gas in the extracted gas and the concentration of the constituent gas remaining dissolved in the gas-containing liquid. The gas sensor senses the concentration of a constituent gas in the extracted gas, in the presence of other constituent gases. The gas sensor comprises a sample chamber which receives the extracted gas, a non-dispersive infrared (IR) absorption sensing system which generates an electrical signal corresponding to the light absorption, at one or more specified IR wavelengths, of the extracted gas in the chamber, and an electrical output comprising the electrical signal generated by the non-dispersive IR absorption sensing system. A processor having receives the electrical signal corresponding to the light absorption, at the one or more specified IR wavelengths, of the extracted gas in the chamber, and computes the concentration of at least one gas constituent present in the extracted gas.

System for measuring gases dissolved in a liquid

An apparatus (10) and a method are described for extracting gas from a liquid containing dissolved gas. The liquid is pumped from an external reservoir (40) of the liquid into a separation cell (14) by a liquid-pumping chamber (11). In separation cell (14) a permselective membrane (17) effects extraction of the dissolved gas from the liquid. A gas-pumping chamber (23) pumps the extracted gas from the permeate chamber (16) of the separation cell (14) to a collection station (27), where the extracted gas can be analyzed, separated into its individual components, or stored, as desired.

Apparatus for extracting a gas from a liquid and delivering the gas to a

A method for powering a system for transmitting and receiving multiple telephone transmission signals over a single twisted pair. The method also powers down a portion of the system. An analog signal from a local switching station is converted to an 80 kbits/sec signal for transmission over a twisted pair. A remote terminal converts the 80 kbits/sec signal back into a conventional analog signal for use in conventional telephone, facsimile or other related equipment.

Digital added main line system with power-up and power-down features

A test system directed to apparatus for transmitting and receiving multiple telephone transmission signals over a single twisted pair. The system converts an analog signal from a local switching station to an 80 ksymbols/sec signal for transmission over a twisted pair by a line card. A remote terminal converts the 80 ksymbols/sec signal back into a conventional analog signal for use in conventional telephone, facsimile or other related equipment. The test equipment separately tests the entire system, the line card portion of the system, the remote terminal portion of the system, and the twisted pair.

Alarm and test system for a digital added main line

A method and apparatus for transmitting and receiving multiple telephone transmission signals over a single twisted pair. An analog signal from a local switching station is converted to an 80 kbits/sec signal for transmission over a twisted pair. A remote terminal converts the 80 kbits/sec signal back into a conventional analog signal for use in conventional telephone, facsimile or other related equipment.

Digital added main line system

Gel filled RJ11 connector

Apparatus and method for monitoring a self-regulating heater comprising a PTC conductive polymer while it is being powered by a power supply signal. The apparatus is connected to a power supply and to the heater, the heater then producing a heater signal which is fed to a comparator. The comparator deterines the phasal relationship between the power supply signal and the heater signal and indicates when the signals are out of phase by a predetermined magnitude.

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San Jose, CA, United States of America

David C Bliven