Pump Maintenance: An Inside Job:

Located in Southwest Ohio, Greater Cincinnati Water Works (GCWW) supplies more than 43 billion gallons of water a year, utilizing a surface water plant equipped with eight raw water pumps capable of producing 240 million gallons per day, a ground water plant utilizing 13 wells capable of producing 40 million gallons per day, and 94 finished water pumps supplying water to 1.1 million customers.

The western service area of the system is partially supplied by the Western Hills Pump Station (WHPS), which is a major booster pump station within the GCWW system. The current pump station was completed in 1937 as a replacement for a smaller pre-existing station, and to meet the increasing demand of the area. The original pump station was built in 1907, but by 1930 was operating at max capacity and a larger station was required. Years of debate and analysis were taken to determine if the new station should be steam operated or electrified, as all of GCWW’s pumps were steam driven at that point. Ultimately the utility settled on electrification of the station.

Low efficiency, reduced reliability, and predictive maintenance assessments led to discussions and planning for the future of this pump unit.

Joseph G. Steinkamp was hired as the architect and GCWW employee Charles H. Anderson specified and designed the pumps and control devices. Construction was completed between 1934 and 1937 at a cost of $312,000. Upon completion, the station was considered the most modern in the United States. Decorated in art deco design and constructed of limestone with intricate carvings at the entrance, the building is extravagant for a pump station.

Detail was not limited to just the exterior of the building. Ivory terracotta tile covers the walls, which are topped with ornate plaster inlays and chrome trim. Spread across the pump floor are five, two stage De Laval Double Suction pumps with a combined capacity of 40 MGD. Each pump is trimmed with polished brass accessories to match the design of the building. Massive windows allow natural light to enter and reflect off nearly every surface.

Working routinely in a building of this caliber led GCWW Machine Shop to turn a recent pump rebuild into much more. Pump Unit 4 is a two stage De Laval pump that has been in front line service since November 17, 1937. Low efficiency, reduced reliability, and predictive maintenance assessments led to discussions and planning for the future of this pump unit. Total replacement was considered, but high replacement costs and extensive piping reconfiguration would be required. Budgetary estimates for a replacement two stage pump were in excess of $1 million. This quickly led staff to explore the total refurbishment of the pump unit.

Refurbishing a pump of this age would lead to many challenges, such as obsolete pump components, coordination with machining vendors, and a limited window of time to return the unit to service. GCWW determined that to minimize these issues and create the highest quality work product the refurbishment would be completed in-house.

Despite the availability of skilled trades people diminishing every year, GCWW has continued a long-standing tradition of staffing a machine shop with manual machines and in recent years added CNC machinery. Having the capabilities to produce parts in-house greatly reduces dependency on vendors and allows for more rapid turnaround times. In addition to the machine shop, the GCWW maintenance section also includes a weld shop, carpentry shop, facilities maintenance group, and paint shop; all of which were able to contribute to the overhaul.

From the beginning of the refurbishment, maintenance staff took the opportunity to not only pay tribute to the craftsmen who constructed the building and maintained its mechanical assets for over 80 years, but to showcase the talents of the highly skilled trades people that GCWW employs.

To return the pump to like new condition, staff removed the rotating assembly and the pump bodies before parts were labeled and distributed to the multiple trade shops within GCWW.

A routine rebuild would typically include removing the rotating assembly and renewing its serviceable parts. Returning this pump to like new condition required staff to remove the rotating assembly and the pump bodies. Parts were labeled and distributed to the multiple trade shops. Both pump bodies were media blasted to strip previous coatings and allow for a thorough casting inspection. After 83 years of service, a small crack was identified in the first stage pump discharge nozzle. The machine shop was able to repair this by stop drilling the crack, grooving, and applying a 2-part ceramic compound. With casting repairs completed, staff applied a custom color 2-part spray-on epoxy to the interior and exterior of the pump bodies. GCWW has coated internal pump bodies for decades and credits this practice to the condition of their pump assets today. The pump bases remained in place and required stripping of previous coating to apply the same 2-part spray on epoxy. The original De Laval plaques were removed and media blasted. Each was then hand painted to match the original paint design. Modern bearing monitors were concealed and painted to maintain the historic look of the pump.

To save costs and downtime, GCWW’s Machine Shop staff took on the task of refurbishing the pump.

The rotating assemblies were fully disassembled and evaluated. Staff determined all serviceable parts required replacement. Machine shop staff manufactured new bronze impeller rings as the clearance was no longer within the original specification. New impeller rings ensured proper efficiency and will prevent future component failure. A threaded mandrel gauge was produced to properly match threads to the existing impeller. Shaft sealing was achieved with compression rope packing, but the packing sleeves had developed deep groves and no longer provided an adequate mating surface for the packing. New packing sleeves and retaining nuts were fabricated and fitted. Each rotating assembly is spun on two babbitt lined bearing castings and a single thrust bearing. Each babbitt was blue checked, dry rolled and hand scraped, a skill that has been almost lost throughout the maintenance industry today. This process ensures the babbitt contacts the journal as uniformly as possible. The impellers had minimal material loss and were media blasted to remove previously applied coating. New coating was applied, and the full rotating assemblies were dynamically balanced.

WHPS was staffed 24 hours a day until the mid-‘90s when more modern automated controls were installed. While staffed, one of the weekly tasks included hand polishing the bright work on each pump. As on-site staff decreased, this practice was abandoned. Much of the elegance and appeal of this equipment was the high level of detail originally applied to each pump. Staff were able to restore the original bright work and original pressure gauges were disassembled, hand polished, and returned to operational condition. Over 100 individual fittings, lines, and accessories were cleaned, inspected, and hand polished. Once brightwork polishing was complete, a clear coat was applied to each to maintain the shine for years to come.

Staff were able to restore the original bright work and original pressure gauges were disassembled, hand polished, and returned to operational condition.

Just a few months later, staff returned both pumping assemblies to their bases and started the final assembly process. After assembly, the pump was laser aligned and final testing was conducted. Shortly thereafter, Pump Unit 4 was returned to operational service. Total refurbishment costs were approximately $60,000, which was a significant savings to the utility. After this overhaul, the pump was in condition to both supply water for years to come as well retain its place in this historic pump station.

The overhaul of Pump 4 provided an opportunity for GCWW staff to keep an aging asset in service well beyond its expected lifespan, as well as provide a team building experience that was greater than a pump overhaul would typically provide. Every group that worked on the pump overhaul was able to showcase their abilities and share in the experience of refreshing a historic piece of equipment that will continue to serve GCWW’s customers for decades into the future. WW

About the Authors: Justin Barkey is a plant maintenance supervisor at Greater Cincinnati Water Works in Southwest Ohio with over 20 years of mechanical maintenance experience. He manages pump station maintenance, capital valve replacement, and the utility’s pressure regulator program.

Greg Roa, P.E., is a Supervising Engineer with the Greater Cincinnati Water Works with over 22 years of experience in utilities industries. He manages mechanical and facilities maintenance as well as capital projects for the utility’s supply division.