Converting Corroded Circulating Pumps to Mechanical Seals

"The amount of corrosion involved would have made this project impossible to do if it were not for the Climax portable boring bar. The tool enabled me to make the repair on site, saving substantial time and labor." - Nick Hughes, Vice President Field Service, J-S Machine & Valve, Nowata, OK

Situation

• Wear and leakage are common maintenance problems affecting pump efficiency. Converting pumps to mechanical seals eliminates fretting or grooving of the shaft, and enables easier maintenance of the pumps.
• When J-S Machine & Valve was contracted to convert a circulating pump at a coal-fired plant to mechanical seals, they knew from experience that such conversions can be difficult. Both the large size of the pumps and the extensive repairs often required beforehand to address existing corrosion can make the process long, grueling and expensive.

Challenge

• During inspection, J-S Machine & Valve personnel found that the pump casings were severely corroded around the stuffing box faces that were to be used as a gasket surface for the mechanical seals.
• The stuffing box face had to be realigned and machined to provide a true, flat surface for the gasket before the new mechanical seals could be installed.
• The circulating pump was more than 11 feet (3.35 meters) deep. The company’s most capable machine tool for such a job, a Climax BB5000 portable boring machine, had only a 6-ft (1.83-meter) bar.

Solution

• Rather than buy another boring bar, J-S found that Climax had a longer, 12-foot (3.66-meter) portable boring machine with heavy-duty facing attachment available for rental and overnight delivery.
• The machine’s heavy-duty facing head provides a high metals removal rate to handle large diameter facing jobs and can achieve a flatness of 0.003 over 20 inches.
• To position the machine’s bar from one end of the pump to the other, a J-S Machine & Valve machinist crawled inside the pump and, with the top half of the pump casing removed, the bar was set in the bore with the I.D. bearings. The top was reinstalled and mounts were made to place the adjustable bearing on the outboard ends of the pump. That allowed the bar to be adjusted and the drive and feed to be hooked up.
• With the bar in place, machinists used an indicator to ensure it was perpendicular to the shaft and parallel with the installed bearings, ensuring proper alignment of the mechanical seal.

Results

• Repairing pipes like these to their proper dimensions and installing the mechanical seals can take as long as 80 hours to complete. But because this was done on site with a powerful and precise machine tool, it took less than 25 hours.
• Converting to mechanical seals will enable the circulating pumps to maintain their maximum efficiency and provide for more trouble-free maintenance in the future.
• Besides pump work, J-S Machine & Valve has extensive experience in on site repair and maintenance of valves and other equipment used in the petrochemical and power generation industries. The company credits Climax as a key contributor to making what were once nearly impossible jobs routine.

"J-S Machine & Valve has built a strong reputation in the petrochemical and power industries by providing on-site repair and maintenance services that are both efficient and cost-effective so plants can get back on line faster. We are proud to partner with this leading company and to be able to provide the kind of tools that help it grow business."

- Geoff Gilmore, president of Climax Portable Machine Tools