Problem:
This pump is driven by a 1.25mW motor. Taken out of service as the efficiency had fallen to below 70% of that when it was new. There was also concern that the steel fabricated body was worn to an unacceptable thickness in places. The repair was expected to return the pump to at least 95% of new and give a new life of over 10 years before the efficiency dropped to an level requiring a further overhaul. Previous overhauls had lasted about 5 years.

Solution:
With the pump dismantled a temporary structure was built around the body to contain the blast media and provide a controlled atmosphere for heating the metal. A package heater was installed for the duration of the repair.

The edges of the diffuser blades were cut back and new metal welded in to provide a structure. Over 100kg of ARC 897 was applied to reform the profile of the various parts. This was finished with ARC 858 which was also applied to the volute parts where significant we had taken place. The complete body was then sprayed internally with ARC S2 to provide a low coefficient of friction, but hard wearing surface.

The Impeller was taken back to our workshops, where it was repaired using ARC 858. It was then dynamically balanced and finally completely coated with ARC S2, hand applied.

The complete repair was carried out in 3 weeks.

Savings:
The pump is now pumping at 104% capacity compared to when it was new in 1966. With this increased capacity, the return on investment (ROI) has fallen from an anticipated 3 years to less than 18 months.

Anticipated life of the repair is at least 10 years, with a drop in performance being dramatically reduced over this time as tolerances are maintained and internal energy consumption reduced.