RF-Safe Detonator Circuit with Spark Gap Isolation
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Solution Overview
Problem
Conventional primary explosive detonators in the oil and gas industry are highly sensitive to radio frequency (RF) and stray voltage exposure, leading to unsafe environments and potential accidental detonations, with existing cost-effective solutions being inadequate.
Innovation Solution
A resistorized detonator circuit incorporating a spark gap circuit and shunt capacitors to increase the voltage threshold for ignition, providing RF and stray voltage protection while maintaining cost-effectiveness, using resistors and capacitors in series with the electric match to reduce sensitivity and a spark gap circuit to ionize gas and reduce electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional primary explosive detonators are used, then they are easy to manufacture and cost-effective, but they are highly sensitive to RF and stray voltage exposure causing safety issues
Solution Approach 1:
A spark gap circuit is introduced as an intermediary component between the electric match and the primary explosive. The spark gap acts as a mediator that blocks RF and stray voltage from reaching the sensitive explosive while allowing controlled ignition current to pass through, thereby improving safety without significantly increasing manufacturing complexity
Solution Approach 2:
The patent uses inexpensive, readily available components (resistors, capacitors, spark gap) to create a protection circuit that can be easily manufactured and disposed of after use, avoiding the need for expensive, complex EBW or EFI systems while providing adequate protection against RF and stray voltage
2Ease of manufacture
If resistorized detonator circuits are used to reduce sensitivity, then cost is reduced compared to EBW/EFI, but they still require additional components increasing circuit complexity
Solution Approach 1:
The patent combines the spark gap circuit with resistorized detonator circuits into a unified protection system. The spark gap, resistors, and capacitors are integrated into a single circuit assembly that provides both RF protection and sensitivity reduction, avoiding the need for separate protection devices and reducing overall system complexity
Solution Approach 2:
The resistorized detonator circuit with spark gap serves multiple functions simultaneously: it provides RF protection, stray voltage protection, sensitivity reduction, and maintains the ability to ignite the primary explosive when properly triggered. This multi-functionality reduces the need for additional separate components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified detonator circuit significantly raises the threshold for stray voltage and RF exposure, reducing the risk of accidental ignition, offering a cost-effective alternative to more expensive Exploding Bridge Wire and Exploding Foil Initiators, ensuring safer operations in oilfield applications.
Implementation Method 1
a spark gap circuit to ionize gas and reduce electrical resistance
Implementation Method 2
resistors and capacitors in series with the electric match to reduce sensitivity
Implementation Method 3
Electric current is passed through the match causing Joule heating that in turn causes the ignition mixture (100) to ignite
Data Source
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AI summary
An radio frequency (RF) safe, high standoff voltage, ESD protected primary explosive detonator is described. The primary explosive detonator includes an isolated spark gap (SG) circuit and one or more shunt capacitors to insulate the electric match from ignition when exposure to high stray voltage or RF occurs in oilfield applications.