Abstract: A single optical fibre cable signaling system is provided between a central station and a remote location wherein a shutter element is movable between first and second positions at the remote location in response to a change in the measured variable. The shutter element and the interior of a housing surrounding the end of the cable have cooperating light reflecting and light absorbing surfaces which are effective in one position in the shutter element to absorb unmodulated light transmitted from a source of the central station over the cable to the remote location and prevent the same from being transmitted back over the cable and are effective in the other position of the shutter element to reflect unmodulated light transmitted to the remote location back over the cable to the central station.

Abstract: A method and apparatus is disclosed for separating a liquid product from a hydrocarbon-containing feed gas, such as natural gas, including introducing the feed gas to a heat exchanger; cooling the feed gas in the heat exchanger to condense a portion of the feed gas to form a first vapor fraction and a rich liquid fraction; flowing the first vapor fraction at a predetermined inlet pressure through an expansion valve to reduce the pressure of the first vapor fraction to a pressure at or below 1/3 of the expansion valve inlet pressure; flowing the rich liquid fraction through a second expansion valve to reduce the pressure of the rich liquid fraction to a pressure at or below 1/3 of the second expansion valve inlet pressure; introducing the cooled first vapor fraction and the cooled rich liquid fraction into the heat exchanger for indirect heat-exchange with the feed gas to cool the feed gas; removing the rich gas from the heat exchanger; condensing a portion of the rich gas to form a liquid product and a rich v