Abstract: An alarm system includes alarm monitoring subsystems coupled by communication links to a central alarm processing subsystem. Each alarm processing subsystem includes sensor strings for detecting alarm conditions in a monitored region and means for locating a detected alarm condition along the length of a sensor string. An alarm message including a system identifier, a sensor string identifier and the distance of the alarm condition along the sensor string is communicated to the alarm processing system. The alarm processing system displays a stored representation of the monitored region when an alarm message is received. The system and sensor identifiers and the cable distance data are used to convert the cable distance into the coordinates of the physical location of the alarm condition and a marker of the alarm condition id displayed with the representation of the monitored region.

Abstract: A new and improved method and apparatus is provided for welding together abutting end faces of adjacent dual containment pipe sections of the type described while an elongated flexible cable is present and extending between the adjacent pipe sections. The apparatus includes a unique heater element having opposed heating surfaces and openings formed along diametrically disposed confronting edges for accommodating an elongated cable element so that the pipe sections can be welded together while the cable element is in place.

Abstract: A leak detector and locator utilizes an electrical cable disposed in proximity to fluid carrying pipes or other area wherein a leak may occur. Pulses are applied to the cable and the reflected waveform is analyzed to detect changes in the characteristic impedance of the cable caused by fluid penetrating the insulation of the cable. A different portion of the waveform corresponding to a different point on the cable is sampled after each pulse is generated and stored until the entire waveform has been sampled and stored. Subsequent samples of the waveform are compared with the stored waveform and a leak is indicated if the subsequently sampled waveform differs from the stored waveform by a predetermined amount.