Vulcan Seals Delivers a Custom Solution for a Major UK Power Plant

Overview

A major UK power plant faced a significant issue with one of its large Duechting® ROWA-MCC recirculation centrifugal pumps, which had begun to leak, causing operational disruptions. These pumps are critical to the plant's process of removing sulphur dioxide from coal using limestone slurry. Each of the 20 pumps in the array is powered by a 580 kW electric motor and operates under demanding conditions, including high temperatures of approximately 80°C and an abrasive media.

After five years of operation, the seals on one of the pumps began leaking due to clogging of the springs by the abrasive media. This blockage caused the sealing faces to lose alignment, compromising their function. Despite the urgency, the original seal supplier declined to offer support due to the pump’s size and the extent of the leakage. With no assistance from the original supplier and the critical nature of the pump, the plant urgently sought help from Vulcan Seals.

The challenge

The plant required an immediate and reliable solution to prevent further downtime. Replacing or repairing the seals through the pump’s original equipment manufacturer (OEM) would have involved high costs both in terms of parts and time. Faced with these challenges, the plant’s chief engineer sought a more cost-effective solution and approached Vulcan Seals to design and supply custom seals capable of withstanding the harsh operating conditions and abrasive media.

Vulcan Seals’ solution

Vulcan Seals promptly conducted a site visit to assess the condition of the pump and its seals. After a thorough investigation, they confirmed that the cause of the leakage was due to the springs becoming clogged by abrasive slurry, preventing the seal faces from aligning properly. Armed with this knowledge, Vulcan Seals initiated the design and manufacturing of a custom seal to address the plant’s unique operational requirements.

1. Custom design collaboration
   Vulcan Seals worked closely with the plant’s chief engineer to develop a custom solution. Using the worn parts and technical drawings provided, they designed a bespoke replacement seal. In addition to the current repair, Vulcan Seals was also tasked with designing seals for other pumps in the plant’s system. During the design process, Vulcan Seals identified opportunities to improve the pump’s performance, specifically enhancing the drive and anti-rotation pins, ensuring better longevity without requiring modifications to the pump itself.
2. Advanced material selection and manufacturing
   Vulcan Seals utilized advanced manufacturing capabilities to produce a high-performance mechanical seal. To handle the abrasive slurry and high temperatures, Vulcan Seals selected Sintered Silicon Carbide for the seal faces, known for its durability and resistance to wear. The custom seal was designed for a large shaft sleeve size of 250mm, with a face operating diameter of 294mm. Both the rotary and stationary seal faces were crafted from Sintered Silicon Carbide, while the stationary seal retainer was constructed from ultra-high molecular weight polyethylene (UHMWPE) and featured 36 springs to enhance durability and prevent misalignment.
3. Precision engineering for large-scale applications
   This project marked a significant achievement for Vulcan Seals, as the custom seal manufactured was the largest the company had produced to date. The successful design and engineering of a seal for such a large-scale, high-demand application showcased Vulcan Seals' ability to deliver precision-engineered solutions for critical industrial processes.

Outcome

The custom-designed seal was successfully installed, and the pump was restored to full operation with no further leakage issues. The new seal performed flawlessly, demonstrating durability and reliability beyond the original specification. The plant reported a significant reduction in maintenance requirements and expects the seal to exceed the service life of the original component, providing long-term cost savings and increased operational efficiency.

Conclusion

This case study illustrates how Vulcan Seals stepped in to provide a high-quality, custom-engineered solution where the original supplier could not. Through advanced materials, precision manufacturing, and a collaborative design process, Vulcan Seals developed a custom seal that not only solved the plant’s immediate problem but also delivered improved performance and long-term reliability.

For industries facing similar challenges with complex or critical equipment, Vulcan Seals offers a wealth of expertise in designing and manufacturing custom mechanical seals that meet specific operational requirements. To learn more, contact your Vulcan Seals account manager or visit the company’s website.

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