The application of coating technology supplier Thermaspray’s protective thermal spray coatings is claimed to reduce degradation processes on performance-critical pump components to extend their operating life and improve pump efficiencies for the best uptime and increased production.

The company, based in Olifantsfontien, notes that pumps are essential in many heavy industries, including mining, petrochemicals and power generation. As they normally operate in extremely stringent and corrosive environments, they are subject to degradation processes, such as mechanical wear, corrosion and cavitation, which “assault” the performance-critical surfaces of pumps, leading to increased vibrations, a reduction in service life and a continuous decline in throughput and pump efficiency.

Over the last decade, there have been significant technological advancements in the field of thermal spray coating technology, with new coating materials and spray processes significantly outperforming more traditional coatings. Thermal spray refers to a coating process whereby a molten stream of particles is projected onto a surface. “Thermal spray is a collection of techniques, which include high-velocity oxygen fuel, plasma, flame spray and arc spray, used to apply materials to substrates,” explains Thermaspray spray shop manager Paul Young. “These techniques can be applied in any industry, from mining to printing, where there are surfaces suffering [from] decay.”

The manufacture of critical components from optimal wear- and corrosion-resistant materials is often restricted by cost considerations, so most of the work that the company does is on new replacement pump parts for key original- equipment manufacturers (OEMs).

However, refurbishment is possible on parts that have not been too severely damaged, Young explains. “To prepare a new or worn part for coating, we take it down to the substrate and we have the necessary experience and capabilities to produce the final product, new or refurbished, to original equipment specifications.”

New uncoated internal components, such as impellors, casing rings and shafts, are normally received from the OEMs disassembled. Once Thermaspray has applied the relevant coatings, the parts are returned to the OEMs for reassembly. The application of protective coatings to OEM parts offers substantial cost saving benefits to end-users. Coated OEM performance-critical parts can be refurbished and reused, whereas uncoated OEM parts are normally so badly damaged that refurbishment is impossible. “Coating of OEM parts often facilitates assembly, as parts are easier to slide on and off,” adds Young.

He also points out that small faults can occur on parts during the manufacturing process. “Coating these defective parts is a faster and much more affordable process, compared with scrapping and manufacturing a new part. We can also assist with bringing an undersized part to size.” The company can also apply thermal spray coatings to spares so that, when they are used for replacement, they are already protected.

Thermaspray is able to refurbish worn parts that have not been too badly damaged by corrosion, erosion, wear and tear caused by rust, acid or salt water, says Young. “As these parts are uncoated, we first have to remove the damage – dents or corroded areas – before applying the thermal spray coatings.” The removal of the coating material through a grinding process and the reapplication of the coating can extend both the pump and the coated part’s service life by two or three times.

By increasing mean time between failures, the extension of the replacement period will lead to substantial savings on replacement costs and keep downtime to a minimum. “Further, refurbishment of a used pump can deliver savings of between 45% and 65% on the cost of a new pump,” he remarks.

Thermaspray, in a joint venture with Cape Town-based Surcotec, offers an extensive portfolio of engineering and thermal spray coating solutions that extend component life cycles to assist OEM and end-user clients across Southern Africa in reducing costs and increasing production. The companies’ high-quality wear- and corrosion-resistant thermal spray coatings, plasma transferred arc cladding and polymer coatings – in partnership with Plasma Coatings of the UK and Diamant Metallplastic of Germany – are augmented by a host of specialised allied services.

Thermaspray has close to 20 years’ experience in wear- and corrosion-resistant thermal spray coatings. The company says its in-house, metallurgical laboratory is the only dedicated facility of its kind in Africa’s thermal spray industry and is equipped to undertake “world-class” developments and quality control.