The Progress Energy’s Lee Plant, located in Goldsboro, N.C., originally enlisted nine vertical sump pumps within the plant as yard drain pumps – pumps that have motors that are located above the pump and a line shaft that extends down into the length of the sump – whereas the pump is actually at the bottom of the sump. The pumps were enlisted to remove excess water that accumulates from rainfall and storm drains, equipment wash down and general water overflow — all of which are pumped to a retention settlement basin.
As a result of pump age, maintenance of these pumps became increasingly more expensive. Plant management began to question the long-term feasibility of efficiently maintaining the pumps and their ability to continue to meet the plant’s operational expectations. “We were having reliability problems with our vertical line sump pumps,” said Ed Davis, a senior work management specialist with Progress Energy. “In fact, we were rebuilding the pumps on a regular basis.”
To address potential solutions to this challenge, Davis consulted Bill Lynch of Tencarva Machinery Company, an employee-owned company that specializes in rotating equipment and wastewater pumps for industries such as the power-generating segment. With a team of more than 50 engineers and a customer support staff of over 75, Tencarva brings the collective expertise found in its 20 branches, spanning seven states, to each customer engagement.
As part of the initial engagement, Tencarva came to the power plant and evaluated the current technology being enlisted, the overall design and the future needs of the plant. As part of this initial assessment, the application, in terms of horsepower requirements, was matched with available technology to yield the greatest impact.
As a result of that conversation, the team strategically made the decision to move away from the traditional vertical line sump pumps to more effective self-priming, centrifugal pumps. With the new technology, Progress Energy was able to capitalize on the unique design of the pump, placing the pump totally above ground at the top of the pump station with only a suction line submerged below grade level.
When Progress Energy learned about the opportunity to install new, more efficient and easier-to-maintain pump technology for less than they could rebuild their current pumps, the decision was simple. In the end, Gorman-Rupp’s Super-T technology was chosen. The team installed a series of pumps, in various sizes, including 4”, 6” and 8” pumps. “When we compared the price of the new equipment to the cost of the existing maintenance program, we felt justified in investing in new motor skids and controls as well,” said Davis.
To test the performance and effectiveness of the equipment prior to making the decision to invest in a complete overhaul, the energy leader chose to install a two of the new Gorman-Rupp Super-T pumps on a trial basis. To begin the assessment, Progress Energy ordered two of the new pumps and installed them over the course of approximately 18 months. Tencarva estimates that the normal installation time of pulling old technology out and installing new technology, including making the appropriate piping and electrical modifications to be roughly two weeks for two to three men. “We wanted to make sure our investment was sound and that we had time to observe the pumps closely,” Davis said.
Since that initial test period, Progress Energy has replaced nine of the vertical pumps with Super-T Series technology – seven of which are performing the yard drain functions previously held by the VLS pumps. “Tencarva did an excellent job of matching the new equipment to our existing structure,” said Davis. “The switchover was completed simply and efficiently.”