03961308 is referenced by 23 patents and cites 5 patents.

A signal is transmitted through the walls of tubing extending down into an oil well in order to control a disaster valve at the lower end of the tubing. If the signal disappears, the valve shuts. In one embodiment, the tubing functions as the core of a transformer. In another embodiment, the tubing conducts an acoustic signal.

Title
Oil and gas well disaster valve control system
Application Number
5/294289
Publication Number
3961308
Application Date
October 2, 1972
Publication Date
June 1, 1976
Inventor
William H Parker
Hurst
TX, US
Assignee
Del Norte Technology
TX, US
IPC
E21B 35/00
G01V 1/14
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