FLOW & LEVEL CONTROL RAPID OPENING MEANS QUICKER SERVICING


Sean Hawe, business development manager and Mick Collins, global sales director, CIRCOR International, explain how fail-safe ROCs improve safety, and reduce both downtime and the need for multiple operators


opening a pressurised pipeline for cleaning and inspection, that resulted in hours of effort by multiple operators. The introduction of pressure vessel closures was an improvement over this technology, which enabled access with slightly more ease. However, not all closures are created equal.


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Slow and challenging to operate bolted clamp and threaded type closure designs aren’t the only closure technology available on the pipeline market. Rapid-opening closures (ROCs), whose designs have been honed and improved over the past two decades or so, can simplify the opening process such that a single operator can safely and quickly open a pipeline door in minutes, without any special tools. This simplifies maintenance, reduces the number of field operators required, and is a simpler, safer, cleaner, and easier-to-use alternative to traditional techniques. In applications where frequent


access is necessary, or where larger pipelines or pressure vessels are in use, traditional closure systems are prohibitively large and heavy. Eliminating downtime while improving ease and safety, can offer efficiency and cost benefits. What’s more, many


traditional designs of pipeline closures feature external locking mechanisms and safety elements that are exposed to the weather and harsh exterior environments. These aggressive conditions can increase both danger and difficulty of opening in traditional closure designs. Finally, traditional closures are typically


designed to standard flange pressure class ratings; Class 600, 900, 1500, and 2500 respectively. However, pressure vessels are not always designed to the same standard class ratings, and so discrepancies may result in pipeline closures that are far heavier and more expensive than is necessary. Rapid opening closures (ROCs) for pipelines


and pressure vessels were designed to eliminate the challenges of efficiency and safety posed by more traditional closure


any pipeline launchers and receivers in the 1960’s utilised flanged entry technology, de-pressurising and


designs. These ROCs are manufactured to the same design code as traditional ones (e.g., ASME Section VIII-Division 1), but incorporate improved safety features such as pressure warning interlocks and fail-safe design measures. Furthermore, these safety features are designed in a way that still enables far faster access, with fewer operators than traditional designs. Take, for example, the ROCs manufactured


by CIRCOR Pipeline Engineering. These closures can be opened by a single operator in less than one minute, without any special hand tools. They also incorporate the required safety mechanisms to prevent the operator from opening the closure when residual pressure is present. With CIRCOR’s ROC, the actual pressure warning feature and mechanical interlock device are one and the same. The pressure warning indicator mechanically interlocks with the drive plate mechanism to prevent the closure from being opened. Thus, by combining these separate safety elements into a single component, the closure meets all critical safety standards but also avoids the time- consuming


operation of separate stand-alone elements. The CIRCOR ROC features fail-safe


technology that ensures the failure of any single closure component will result in it failing to a secured closed position. What’s more, these mechanisms are housed within the closure door itself and are protected from the harsh environments of both the exterior and interior of the pipeline. This particular ROC also features a recessed


self-energised lip seal, which requires no mechanical force to close and seal and far less frequent changes than compression O- ring type seals. Given that the self-energising lip seals can last months or years before requiring replacement compared with O-rings that can survive only a single opening cycle, the total cost of ownership is also lower.


The demand for increased pipeline inspections and the change out of filters has increased opening &


closing frequency. Consequently, the speed of access to reduce downtime has become a critical focus


ROCs deliver benefits over traditional


designs across a wide range of applications, from oil and gas pipelines to filtration or separation pressure vessels, sour-service (H2S), or high-corrosion conditions (saltwater & brine). The more frequently these pipelines or pressure vessels must be cleaned, inspected, or serviced, the more worthwhile a ROC becomes. Given that ROCs can eliminate multiple days of downtime, even pipelines and vessels that must be opened once every quarter can see a rapid ROI. In high-pressure pressure vessels and


pipelines, safety is both critically important and challenging to achieve. The safety features inherent in CIRCOR’s ROC design deliver higher peace of mind than traditional options, even with less operators needed. A final benefit of CIRCOR’s ROCs, most


evident in pressure vessel applications where large and high-pressure pipelines are in use, is the ability to design the closure to each individual application’s parameters of size, pressure, temperature, and more without sacrificing the ease of operation. One person can operate closures of up to 72” in diameter, and that closure can be ideally suited to its particular application. This is in direct contrast with the challenge in having to size traditional closures to the closest safe pressure class, even if that means added weight and cost. CIRCOR can design its closures to suit specific design pressures intermediate to traditional flange classes, making them less expensive and lighter in many applications. Capable of maintaining and even


improving safety while reducing working hours and downtime needed to service pipelines, ROCs can be a significant source of cost savings over the lifetime of an asset.


CIRCOR circor.com


MAY 2021 | PROCESS & CONTROL 17


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