Asymmetric Threaded Tandem Prevents Reverse Installation
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Solution Overview
Problem
Existing threaded tandems for perforating gun systems lack a mechanism to prevent installation errors, which can lead to catastrophic failures during assembly of the gun string in wellbore operations.
Innovation Solution
A threaded tandem with dissimilar thread patterns on its externally threaded end portions, ensuring that the tandem can only be installed in a single direction, thereby preventing reverse installation and potential failures, by varying parameters such as thread profile, pitch, diameter, and angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional threaded tandems use identical thread patterns on both ends, then the assembly process is simple and quick, but installation errors can occur leading to catastrophic failures
Solution Approach 1:
The patent applies asymmetry by configuring dissimilar thread patterns on the first and second externally threaded end portions of the tandem. The first thread pattern differs from the second thread pattern in at least one parameter (thread profile, pitch, pitch diameter, major diameter, minor diameter, or thread angle), creating an asymmetric design that prevents reverse installation and eliminates installation errors while maintaining structural integrity
2Reliability
If dissimilar thread patterns are used on the tandem ends, then reverse installation is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by making the thread patterns dissimilar only at specific locations (the two end portions of the tandem) while maintaining uniformity in other aspects of the tandem structure. This localized differentiation prevents reverse installation and catastrophic failure without requiring complete redesign of the entire tandem, thus managing manufacturing complexity
3Ease of operation
If the tandem allows installation in multiple directions, then assembly flexibility is high, but the risk of incorrect installation increases
Solution Approach 1:
The patent applies preliminary anti-action by designing the dissimilar thread patterns in advance to prevent reverse installation before it can cause harm. The asymmetric thread configurations create mechanical incompatibility that physically blocks incorrect installation, eliminating the risk of installation errors while maintaining ease of correct assembly
Data Source
AI summary
An improved tandem for attachment to a perforating gun is provided. The tandem includes a cylindrical body having a first externally threaded end portion and a second externally threaded end portion. The first externally threaded end portion includes a first plurality of threads defining a first thread pattern, and the second externally threaded end portion includes a second plurality of threads defining a second thread pattern. The first thread pattern is different than the second thread pattern such that the cylindrical body is threadably attachable to first and second perforating guns in a single direction. The thread patterns can differ in at least one or more of the following: thread profile, thread pitch, pitch diameter, major diameter, minor diameter, and thread angle, by non-limiting example.