Cleaning Starch and Gluten from Decanter Centrifuges and Progressing Cavity Hopper Pumps

Large industrial mills use, among other things, decanter centrifuges from GEA, which can grind up to 40 tonnes of grain per hour. This is carried off with progressing cavity hopper pumps.

The decanter centrifuges are up to 5m tall and weigh several tonnes. Typically, they remain in continuous operation for a whole year. During this period, starch and gluten adhere to individual components; sometimes they are heavily burnt in and can only be removed manually and with great difficulty.

In addition, the particularly high hygiene standards in the food sector must be adhered to during cleaning.

The decanter centrifuges are dismantled during the annual maintenance cycle and parts such as progressing cavity hopper pumps, housings and the actual centrifuges themselves are cleaned individually by hand with rags and, if necessary, also with chemicals.

The low-pressure hot cleaning process of ph-cleantec works with low pressures of 3 - 7.5 or 3 - 14 bar combined with high temperatures of up to 95°C.

The low pressure is sufficient to rinse off dirt and supports the cleaning process. The actual cleaning effect, however, results primarily from the high temperatures.

Starch, on the other hand, softens at about 40°C, making the method ideal for cleaning starch and gluten.

In this specific case, spraying the parts briefly with water at 95°C proved to be the optimal solution. This softened the starch and gluten adhesions so that they could be wiped off "just like that" with a normal scouring sponge. A short rinse completed the procedure.

Cleaning the distributor plate of a separator shown in Figure 1 took about 8-10 minutes. Manual cleaning, on the other hand, took over an hour and is a tedious and unpopular task that can now be dispensed with.

The drum cover of the separator shown below also needs 1 - 2 hours when cleaned by hand, but here it could be cleaned completely in less than 10 minutes, including the thread on the upper edge.

In this specific case, with our method all cleaning tasks put to us were mastered without any problems. No chemicals were used, only water. Working time was reduced from over an hour per piece to less than 10 minutes.

It was evident to all that the progressing cavity hopper pumps and the centrifuge chassis could also be cleaned without problems, in a fraction of the manual work time and without chemicals.

Because of the particularly high hygiene standards in the food & beverage industry almost exclusively stainless steel units are employed.

In this particular case, a 1000 ESR with a stainless steel chassis was used.

The distributor plate in Fig. 1 was cleaned directly in the stain­less steel collector of the 1000 ESR. The process water could be circulated and reused several times.

• Cleaning even of caked starch and gluten is easy and thorough, as these soften at 40°C; this saves significant working time and is pleasant to work with.
• No damage to sensitive parts due to low pressure.
• Mobility: Units are mobile and self-sufficient, and can be easily transported from place to place. At the same time, minimum space requirement.
• No major splash-back effects, no clouds of droplets, no aerosols, etc., so devices can be used without problems in production halls or in maintenance.
• Occupational safety and environmental protection: Cleaning with water instead of chemicals protects the environment, increases occupational safety and reduces costs.
• High hygiene requirements of the food industry can be easily met with stainless steel units of type 1000 ESR.
• Economics: Significantly less cleaning time, significantly fewer resources and no chemicals mean considerable cost-saving potential and short payback period.
• Overall: Low investment and minimal running costs, but high efficiency, high cleaning quality and considerable savings in working time and resources.