FDBusiness.com

London – Heraeus Noblelight has reported on two recent application of its Infrared heating technology at chocolate manufacturers – both seeking to address quality and production issues with existing heating systems.

At OP Chocolate’s Dowlais, South Wales, factory, a 9kW carbon infra-red heating system from Heraeus Noblelight is helping to ensure consistent chocolate quality while reducing production line down-times. The system is used to pre-heat chocolate moulds prior to filling and replaces a long-established ceramic infra-red system.

OP Chocolate was originally founded in Cardiff in 1938 and production was transferred to the purpose-built site in Dowlais in 1963. The company is now a member of the French Groupe Cemoi. Its 16000 m² factory focuses on wafer and chocolate tablet manufacture.

The production of moulded chocolate involves depositing liquid chocolate into polycarbonate moulds. However, it is important that the moulds are pre-heated to a specific temperature before the chocolate is poured. If the moulds are too warm, the chocolate can change its characteristics and detemper. If they are too cold, the poured chocolate will lose shape and possibly crack.

Previously, OP Chocolate had used infra-red, ceramic heaters to pre-heat the moulds. A shuttering system could be placed between the heaters and the moulds in the event of line stoppage, to prevent spoiling of the chocolate in the moulds during the time it took for the heaters to cool down after switch-off.

However, the ceramic system was proving unreliable in operation and the action of changing over the shuttering was proving increasingly difficult.

Having installed a similar Heraeus carbon fibre infra-red mould heating system on another chocolate tablet production line five years ago, the project engineers at OP Chocolate decided replace the ceramic system with a carbon medium wave system.

This proved to be one third the size of the old system. It features three, 3kW emitters and can be either manually or automatically controlled. With manual control the emitter outputs can be adjusted by the operator to achieve a mould temperature of 30ºC as measured by a pyrometer. With automatic control, the emitters are regulated automatically according to the pyrometer setting.

“The infra-red system …. provides precisely controllable heating for the moulds and their very fast response ensures that line stoppages are now more easily managed and quality improved,” said Peter Smith, project manager at Dowlais.

Chocolate quality

In a similar application, Heraeus installed two carbon infra-red heating systems at the Kinnerton Confectionery Ltd. One system was added to pre-heat chocolate moulds prior to filling and the other to melt chocolate rims prior to rim heating, which involves the fusing of two chocolate halves.

Kinnerton is one of the UK’s largest manufacturer of chocolate and confectionery. Its range includes advent calendars, clusters and chocolate figurines, with bespoke products for many major retailers around the world.

Kinnerton had previously used both metal element heaters and a warm air heating system. The metal element system incorporated a servo system to locate the heating elements over the moulds and, in the event of line stoppage, this involved considerable delay in removing the heaters, which meant that a number of filled moulds were excessively heated.

The warm air heating system took up considerable space and was difficult to control so that heating was not consistent causing quality problems.

These problems prompted Kinnerton to install an infra-red system from Heraeus Noblelight. The 14.4kW carbon infra-red system was installed, featuring a pyrometer to ensure that the moulds are heated to exactly 29ºC. Subsequently, a second 9.6 kW carbon infra-red system was installed for rim heating.

As David Hume, NPD technical process manager at Kinnerton, explains, “The infra-red system, which was retrofitted without any problems into the available space, provides precisely controllable heating for both the moulds and the chocolate rims so that reject levels have been significantly reduced and quality improved.”