River Water Circulator Pump Rebuild - Click Here to view Photo Gallery 

River Water pumps are very common along the “industrial valley” between Baton Rouge and New Orleans.  These pumps come in various sizes from 5000 GPM to as large as 250,000 GPM.  The higher volume pumps are used in power plants and very large petrochemical plants for cooling water circulation.

IPS recently rebuilt a River Water Pump for a chemical plant located on the Mississippi River below Baton Rouge.  This pump is a vertical 3-stage pump, with a capacity of 12,000 GPM. The pump was 50 feet long, with an “enclosing tube design” for line shafting and bearings.  The enclosing tube design serves two primary functions: it protects the line shafting and bearings from the sandy river water pumpage, and accommodates line shaft/bearing lubrication.  Lubrication can be accomplished by grease, oil, or clean water.  A water purge, provided it is clean and of sufficient pressure and flow, usually works best.

This pump has bronze bearings with 416 SS shafting.  The impellers are bronze and bowls are cast iron with 316 SS wear rings.  While these pumps may appear simple and easy to rebuild, attention to certain details is of paramount importance.  Considering the length of this pump (50 feet), one must consider how a small misalignment at the upper end (top), can affect the lower shaft runout. Therefore, all register fits and faces (bowls, columns. and discharge head) must run true.

In this pump, mating registers were reclaimed to a clearance of only .002” or less, and the discharge head was machined to insure concentricity of all fits (driver, stuffing box, and column). The ends of each enclosing tube were faced perpendicular with their centerline.  The line shafting was cleaned, polished and straightened and swapped end for end so that worn journals were not aligned with the bearings.  Re-using the line shafts in this way is very cost effective when compared to replacing with new shafts.  All parts that are re-used are also thoroughly inspected and in some cases are put through some NDT (non destructive testing) inspections to ensure their suitability for continued service. 

All impeller wear rings were machined to insure concentricity with bores.  The impellers (three) were dynamically balanced individually and then as a unit to 4W/N specification.  The tension plate and tension nut were also replaced.  These types of large circulator pumps typically run for several years therefore rebuilding for maximum long term reliability is critical to the owners of these pumps. 

Please see Photo Gallery illustrating the main features of this rebuild.