Introduction
The 4004S Magnetic Pig Signaller is a compact, self-contained, non-intrusive device designed for detecting the passage of magnetic pigs in harsh subsea environments. Unlike traditional subsea signallers, the 4004S is designed for permanent installation on subsea pipelines and can be externally powered through a subsea cable connected to a topside control system. This case study details the development of the 4004S Magnetic Pig Signaller and some of the challenges faced by the IK Trax team.
Project Objectives
The development of the 4004S Magnetic Pig Signaller was guided by three primary objectives. Firstly, the signaller needed to be externally powered via a subsea cable linked to a control system or station topside. Secondly, the device had to be designed for easy installation and removal by divers. Finally, the signaller and clamp assembly, required a minimum operational life of 20 years under subsea conditions. These objectives set the 4004S apart from other subsea pig signallers in the market, particularly those within IK Trax’s existing product range, because the unit could be installed permanently subsea and permanently powered if required.
Design and Development Process
The development process for the 4004S began when the IK Trax sales team identified a potential project that required a new pig signaller meeting the specific criteria mentioned earlier. The in-house R&D department quickly assembled a team of engineers who collaborated to create a concept design which went through multiple iterations and reviews to ensure it met all the necessary requirements. After refining the design, it was presented to the client, who expressed confidence in the unit. Following the client’s approval, a detailed quote was provided. And further refinements were made before the manufacturing phase commenced to ensure all specifications were met.
Meeting Technical Requirements
To meet the technical requirements, the 4004S signaller incorporated several key design features. Powering the unit externally was achieved using a Siemens wet-mate connector, which was permanently fixed to the signaller and designed to withstand external pressures of up to 300Bar. The requirement for diver deployability was addressed by designing a bespoke subsea clamp system that included a funnel mechanism. This system allowed divers to easily install and remove the signaller from the pipeline as needed. To ensure the device’s long-term durability, all metal components were made from super duplex stainless steel, a material known for its resistance to corrosion in subsea environments, ensuring that the signaller and clamp assembly could operate reliably for 25 years.
Client feedback was critical for refining the final design. Specifically, feedback regarding the pipe O/D tolerance allowed the engineering team to fine-tune the clamping mechanism, ensuring it could accommodate the large O/D tolerance of subsea pipelines.
Design Challenges and Solutions
The project’s most demanding design challenge involved creating a locking mechanism that could be easily operated by a diver while ensuring that the 4004S remained securely attached to the pipeline, even under strong currents and potential contact with trawlers. The engineering team tackled this by designing a compression-based locking slot. The mechanism was rigorously tested with various compression forces, leading to an optimised design that balanced ease of use with the necessary security.
Installation Process
The installation of the 4004S is straightforward and diver-friendly, primarily due to its well-designed clamp assembly. The clamp assembly, which is provided with the unit, can be pre-installed onto the pipeline topside, simplifying the subsea deployment process. The assembly includes a built-in funnel designed to accommodate and secure the 4004S signaller once it is deployed subsea. A diver can easily install the pig signaller underwater by using assembly tools to insert it into a locking slot on the funnel. Once the signaller is engaged in the locked position, it becomes securely fixed to the clamp assembly on the pipe. If necessary, the signaller can also be removed by a diver, making the installation both secure and reversible.
Testing and Validation
To ensure the 4004S would perform reliably in its intended environment, it underwent extensive testing. The prototype was subjected to a 22-hour pressure test at more than 1.25 times the operating pressure, which confirmed the signaller’s resilience, with no damage or defects observed. Additionally, the custom-designed electronic PCB was thoroughly tested to ensure it provided the correct voltages and currents for accurate signalling. Before shipping, each unit underwent Factory Acceptance Testing (FAT), which involved powering the unit from a 24V DC supply, monitoring the current loop in both ‘listening’ and ‘detect’ modes, and verifying that the signaller operated correctly.
Conclusion
The 4004S Magnetic Pig Signaller represents a significant advancement in subsea pig detection technology. By closely collaborating with the client and overcoming technical challenges, IK Trax successfully developed a durable, diver-deployable, and externally powered signaller suitable for permanent subsea installation. This project highlights the company’s commitment to innovation and client satisfaction, resulting in a product that meets the highest standards of subsea operation.
