Fail-safe mechanism for generating a pulse indicating the precise moment of firing of an air gun
A new circuit is added to an electrical circuit including two electrodes underwater positioned very close to an air gun gaseous exhaust wherein the exhaust from the firing air gun momentarily blows away the conductive sea water from one or both of the electrodes to produce a high voltage pulse due to the large increase in resistance in the circuit indicating the precise moment of firing of the air gun free of any uncertainty and mechanical noise which normally affects conventional transducers. This new circuit added to the above circuit is a circuit polarity reversing circuit which includes particularly a positive current generator, a negative current generator, and a sea ground for forming a third electron source when any of the two electrodes becomes defective, thus forming a fail-safe system. Further, the resultant circuit changes polarity of the electrodes after each firing of the air gun and periodically reverses the current to the electrodes for reduced plating action on the electrodes and for reduced cross coupling between other channels.
- Assignee:
- Texaco Inc
- Patent Number(s):
- US 4243116
- Application Number:
- TRN: 81-015551
- OSTI ID:
- 6118720
- Resource Relation:
- Patent File Date: Filed date 23 Jul 1979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
MARINE SURVEYS
SEISMIC SOURCES
SYNCHRONIZATION
AIR
ELECTRODES
ELECTRONIC CIRCUITS
HIGH-VOLTAGE PULSE GENERATORS
SEAWATER
SEISMIC SURVEYS
UNDERWATER
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUIDS
FUNCTION GENERATORS
GASES
GEOPHYSICAL SURVEYS
HYDROGEN COMPOUNDS
LEVELS
OXYGEN COMPOUNDS
PULSE GENERATORS
SURVEYS
WATER
580203* - Geophysics- Geophysical Survey Methods- (1980-1989)
420800 - Engineering- Electronic Circuits & Devices- (-1989)