Several sugar mills in KwaZulu-Natal have received productivity-enhancing benefits following installations of engineering consumables and components manufacturer Bosch Projects’ new dimple tube technology, which it developed, analysed and tested over the course of three years.

“By integrating dimple tubes into batch and continuous vacuum pans, there are significant improvements in processing capacity, through more efficient evaporation rates, heat transfer coefficient, energy usage, massecuite circulation and enhanced crystal quality and exhaustion,” Bosch Holdings sugar sector director Murray Stevens explained in a recent press release.

The dimple tube technology, designed by the Bosch Projects research and development team, will ensure that the production capacity is increased by reducing the batch pan cycle time and improving the pan floor capacity.

Overall pan floor performance will be “significantly improved” because the technology decreases the graining volume and, in turn, reduces initial thermal inertia at the start of the pan cycle.

Moreover, the design of dimple tubes means the technology is compatible with existing equipment for retrofit applications, enabling simple and inexpensive upgrades, with minimal or zero vessel modifications.

For example, the dimple tube technology can “increase the heating surface area of an existing vacuum pan by [about] 15% and improve the turbulence and heat transfer characteristics, compared with conventional smooth walled tubes”, Stevens enthused.

“The first pan – completely fitted with newly designed dimple tubes – was installed recently at a sugar mill on the North Coast and is starting to show improved performance. The Bosch Projects team is currently on site gathering the operational data to assess in detail the impact these tubes have had on the pan,” said Stevens.

He also cited a project at a different mill, in which a vacuum pan on refined massecuite was being fitted with dimple tubes. New tubes were installed every week on ‘stop’ days, which, he stressed, highlighted the ease of installation.

He commented that the Bosch Projects team is able to provide customised solutions to diverse industries, including sectors such as sugar and ethanol; commercial and industrial projects; and power utilities and materials handling, by integrating engineering technology and project management.