On July 26, 2017 Flexaseal installed an 11-inch Style 85M split cartridge mechanical seal at one of the hydro-electric power generation facilities for Truckee Meadows Water Authority (TMWA) in Northern Nevada. As the largest split cartridge mechanical seal ever produced by Flexaseal, the 11” seal solved a major challenge for the plant while saving the utility thousands of dollars in downtime and repair costs.
The Challenge
TMWA was moving gritty river water through an Allis Chalmers KH Water Turbine. The existing mechanical packing materials were contributing to extensive wear and severe damage to the turbine shaft. In addition, significant fluid leakage posed a hazard to the generator which was critical for operations.
The lengthy and involved process of replacing the mechanical packing was complicated by the turbine’s 15’ primary shaft. As a result, the operator was often left with a short mean time between failures (MTBF). The cost and downtime due to packing-related wear, as well as the manpower and expenses required to maintain the packing, negatively impacted the facility’s bottom line. These issues urgently needed to be addressed.
In this case, a standard cartridge seal installation wasn’t an option. Because of the turbine’s situational constraints, an alternative was needed that would provide the required sealing capabilities while also minimizing downtime and man hours for repairs.
The Solution
After extensive conversations with TMWA staff about their specific needs, goals, and challenges, Flexaseal provided a complete solutions package:
- Split adapter plate for easy installation on turbine
- 11” Style 85M two-piece split cartridge mechanical seal
- ORM (O-ring mount) split bearing/bushing with an API Plan 32 water flush
- Silicon carbide hard faces
In total, the installation took three hours to complete – a fraction of the time required for mechanical packing maintenance. Installation time included site prep and equipment measurements, including concentricity and perpendicularity readings. The only materials needed for the installation were emery cloth and a shaft lubricant—no hoists were required despite the size of the equipment.
The Results
On-site after the installation, the seal had a smooth start-up and continues to run without issue.
The Flexaseal solutions package solves many of TMWA’s concerns. The Flexaseal Style 85M split cartridge mechanical seal addresses the sealing challenge of axial shaft movement under various loads. The O-ring mount bearing bushing solves the problem of excessive shaft runout, and the hard silicon carbide faces can withstand operation in sediment-laden river water.
Flexaseal Engineered Seals and Systems, LLC welcomed this opportunity to work with TMWA to provide a viable answer to their sealing challenge.
Thank you to the TMWA staff for their contributions to this article!
