What is chocolate compound

sweets processing 3-4 / 2021

In order to improve the manual handling of sacks, reduce dust and prevent pallets from getting into the hygienic mixing room, the Scottish confectionery manufacturer Hannah's Sweets installed a sack emptying station from Flexicon and a pneumatic conveyor system. The system is very reliable and offers consistent performance.

Hannah's Sweets makes a range of confectionery products, including the famous Jazzies and Snowies, chocolate wedges covered with colored pieces of candy. Every week the company processes 50 to 60 tons of sugar, milk powder, whey powder, wheat flour and other dry ingredients in bags of 25 kg. This corresponds to around 300 bags per day, which are emptied at a speed of 1,675 kg / h.

The new feed system had to be able to process material with bulk densities of 208 kg / m3 for milk powder up to 705 kg / m3 for crystal sugar. Hannah's Sweets Managing Director Tom Munro says: "Flexicon offered a turnkey system for all ingredients, while others could only supply parts of what we were looking for."

The Flexicon bag emptying station and the pneumatic conveyor system are combined with an external roller conveyor and vacuum bag lifter. An operator uses the vacuum lifter to move the sacks from pallets onto the roller conveyor, which transports them through the wall into the mixing room to the Flexicon sack emptying station. Equipped with a high-speed vacuum fan, the device sucks the dust generated during the manual emptying process away from the operator to two cartridge filters with a combined surface of 9 m2. The dust accumulation on the outer filter surfaces is blown off in a time-controlled cycle by alternating blasts of air from the nozzles in each filter. The detached dust falls into the 140 l intake funnel. This process avoids waste.

The material is then fed into the pneumatic Flexicon conveyor system Pneumati-Con via the adapter at the bottom of the receiving hopper. Driven by a 7.5 kW fan, it transports ingredients through a 12 m long pipe with a 75 mm diameter to the three pneumatically operated switch valves. Through these valves, three filter receivers with a diameter of 450 mm and the separate mixing containers are fitted one after the other. In the filter receiver, the material is separated from the air flow and dosed into a 28-liter expansion tank through the rotary valve. The material is emptied into a mixing tank where the dry ingredients are mixed with vegetable fats. The resulting liquid chocolate compound is poured into various molds by means of automatic molding equipment.

A PLC controls the system. Each switching and rotary valve is controlled by the signals from the high level sensors of the funnels. A signal of the low level of the bag emptying station stops the fan of the conveyor system. The mixing tanks are filled with a total weight of 2 to 3 tons of liquid chocolate.

The closed system prevents contamination of the product and system environment, while the pneumatic fan evacuates the conveying line. This means that the system no longer has to be rinsed during the material change, because all batch components get into the mixing tanks, which avoids waste. “We have a clean-as-you-go policy, but the new delivery system only requires operators to wipe them every day,” says Tom Munro.

The system has been very reliable and consistent since it was installed. “The lines have been in operation for a year and we didn't have to carry out any maintenance work,” says the managing director happily.