Sweet coating solutions for the sugar industry

Thermaspray thermal spray coatingsSouth Africa’s surface engineering and thermal spray coating technology specialist, Thermaspray offers a range of high quality coating techniques.

These techniques assist the sugar industry in reducing maintenance costs by protecting both new and worn equipment parts and components. It protects them against abrasive, adhesive, erosive and corrosive degradation.

Maintenance costs for the multiple-process sugar industry which includes the crushing, refining and packing of cane and beet sugar can make up as much as ten percent of the value of goods produced. Equipment maintenance as a direct result of abrasion, adhesion, erosion and corrosion leading to rapid wear and corrosion and subsequently expensive downtime can account for up to one third of plant maintenance costs, including replacement and/or repairs.

Best practices

The MD of Thermaspray, Dr Jan Lourens says the company is a DQS ISO 9001 Quality Management and Eskom level 1 certified company. It has close to 20 years’ experience in wear-and corrosion-resistant thermal spray coatings.

‘We possess the necessary capabilities and knowledge of the correct coating techniques and applications using best practices as well as quality control of coating processes that are fundamental to ensuring successful results. The excellent protection offered by our superior quality, highly dependable coating solutions against surface wear and corrosion delivers numerous cost saving benefits including the enhancement of equipment lifespan, a reduction in downtime, replacement and maintenance costs, and improved equipment and plant uptime, productivity and production.’

There are a number of methods Thermaspray implements to overcome abrasion, adhesion, erosion and corrosion specifically in the sugar industry.

Thermal spraying

One such method is thermal spraying, a generic term used to define a group of processes that deposit fine metallic or non-metallic materials onto a prepared substrate to form a coating. The coating material may be in powder, rod or wire form. The different processes include:

  • High Velocity Oxy-Fuel (HVOF)- Operates on a continuous steady-state basis with continuous powder feed. Thermaspray offers two processes . These are gas and liquid fuelled.
  • Wire Arc Spraying is also known as a twin-wire arc spray process. A direct current (DC) electric arc is used to melt the feedstock with compressed air behind the arc atomising the molten material. Higher thermal efficiency is achieved as wires are melted directly. Coatings are coarse with higher porosity.
  • Powder Plasma Spraying­- Plasma (4th state of matter) consists of neutral and positive atoms and free electrons. Plasma gasses are heated as they ionise in the arc and high degree of melting and relatively high particle velocities are achieved. Finely structured coatings with high adhesion strength.
  • Plasma Transferred Arc (PTA) welding and hardfacing process – a versatile method of depositing high quality metallurgically fused deposits on relatively low cost substrates.