04073341 is referenced by 34 patents and cites 8 patents.

An acoustically controlled system includes means for transmitting any of several different forms of sonic energy signals through the walls of a tubing extending down into a gas or oil well. There, any of several functions may be performed, such as a control of a disaster valve located at the lower end of the tubing. Depending upon the function selected, the valve may hold itself open irrespective of the continuity of the sonic signal, or may slam shut if the sonic energy ends. Preferably, the selection control depends upon the pulse repetition rate of the sonic energy pulses.

Title
Acoustically controlled subsurface safety valve system
Application Number
629515
Publication Number
4073341
Application Date
May 3, 1976
Publication Date
February 14, 1978
Inventor
William H Parker
Hurst
TX, US
Assignee
Del Norte Technology
TX, US
IPC
E21B 33/03
E21B 43/00
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