September 24, 2019 | 2 minute read
One of the world’s largest water-treatment facilities in the Middle East, responsible for 60 percent of domestic wastewater and 20 percent of overall water needs, found itself experiencing reliability issues with its original equipment manufacturer’s (OEM) slurry seals that were installed when the equipment was commissioned.
Despite external flushing, the seal’s design was inadequate and unreliable, requiring expensive repairs within two to three months, and replacement every six months.
The facility looked for a cost-effective way to stop the repeated unplanned downtime and high maintenance costs from the unreliable seal. To solve this problem, a team of John Crane water application experts inspected the installation to locate the problem. Following a comprehensive diagnostic check of the facility’s wastewater and reclamation equipment, the team discovered that an improperly designed OEM mechanical seal was the root of the reliability issue.
Instead of recommending another standard slurry seal, the team called upon its experience working with other abrasive slurry, sludge clarification and treatment facilities worldwide. They also considered existing corrosion on the shaft sleeve, also supplied by the OEM, and unique dimensional considerations that needed to be addressed for a long-lasting solution.
Following the detailed assessment, a new shaft sleeve, as well as John Crane’s T5840 single-cartridge slurry seals, were installed to reliably handle the facility’s heavy water-treatment volume, critical to the region’s industry, farms and people. The cartridge seals were installed to operate in the facility’s abrasive slurry conditions to keep the machines up and running. Designed for process pumps and other rotating equipment, the T5840 single-cartridge seals contain robust primary and secondary seal face materials, helping to mitigate the OEM design defect.
Non-clogging, elastomer-encased cone springs apply constant spring load in the seals, eliminating dynamic O-rings and associated hang-ups. The T5840 seals operate without flush or water quenches, making them the correct general-purpose, low-maintenance seal choice for the facility’s slurry operations.
In the 65 months since the upgrade, the T5840 seal is receiving satisfactory reviews from the end user and today, the repaired equipment continues to run without leaking.
Improvements in performance reliability are delivering significant maintenance cost savings for the end user. The upgrade is providing increased equipment availability within the facility. A senior project engineer is encouraged by the results to date, saying he has plans for similar upgrades, “Which will deliver significant cost savings and performance benefits for the plant.