Heated magnetic filter removes iron particles from liquid chocolate

Inline magnet filter for chocolate | Goudsmit Magnetics

Double-walled magnetic filters from Goudsmit remove tiny iron particles as small as 30 µm from liquid chocolate. Heating the filter housing with warm water keeps the chocolate liquefied. The design of the magnetic filter was recently modified at a customer's request to include a sieve that filters out product impurities, such as paper, plastic particles and stones.

Extra sieve
This sieve is normally a separate unit mounted upstream of the magnetic filter in the production process. In the modified design this is combined with the double-walled magnetic filter, which reduces operations, costs, time and heat loss. Additional benefit: both the magnetic bars and sieve can be cleaned in a single operation.

Pressure pipe
Major chocolate producers in France, Germany, the Netherlands and Belgium use double-walled magnetic filters in their process lines. These remove the metal particles from products that can congeal and are transported under pressure. Hot water flows through the outer wall, which keeps the product liquefied. The maximum working/product temperature is 140 °C. The powerful neodymium-iron-boron magnetic bars present in the core, with a flux density of 10,700 gauss, capture the iron particles in the product, thus ensuring that no contaminants make their way into the final product.

316 Stainless steel
The magnetic filter is made of grade 316 stainless steel and therefore meets the strict requirements (HACCP) applicable in the food industry. The filter is easy to implement in an existing pressure pipe, ranging from 10 to 15 bar. Seals are EC 1935/2004 compliant. The magnetic filter is available in sizes DN50 to DN125.


The existing double-walled magnetic filter was modified at a customer's request to include an additional wall. This creates an air-filled space between the core through which the chocolate or mass flows and the cavity where the hot water flows. This prevents the risk of water getting into the chocolate, which would result in the loss of an entire batch.

Special closure
The customer-specific implementation also includes an additional safety: a special closure on the lid so the lid cannot be opened without tools while under pressure and cleaning does not occur in the product chute. In addition, the designer added a special connection point which allows the user to fit a pressure sensor for regular pressure measurements.

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