Getting the most out of potato crop with pre-sorting, destoner, washing equipment

When producing to a certain end specification it is very important to have the right base material. Some packages require small potatoes, others require large potatoes. The same accounts for discolourations and defects. Some end products will allow for certain defects, other require a spotless base material.

Outfeed sorted potatoes

Pre sorting for the right end-product allows the customer to reach the desired end quality, or improving the quality. And it allows the producer to get a better yield out of his base product; when a truckload is not 100% perfect, he can sort out the bad potatoes and still use the majority of the load. Without a sorting line, he may be forced to reject the whole truckload. Various defects and foreign materials are difficult to sort when the product is still dirty. That is why many processors have decided to wash every truckload straight after receiving it. The washing allows them to clean the truckload from stones, floating parts and clay/sand. The benefit is also that the factory is easier to clean and maintain since the dirt all stays in one place at the receiving end of the plant. The other advantage is that it allows them to use optical inspection (manual or with optical sorter) of the raw material straight after receiving so they know exactly what kind of quality is available for their process. Another advantage of a good washing line is that it removes many of the rotten spots should they occur on the potatoes in the truckload.

Floating parts removal, float bath, small parts separator and water recirculation in 40t/h washing line.

However, when washing straight after receiving it is required to have a high capacity washing line, since the delivery of potatoes is not consistent during the day and night. Tummers has installed many turn-key washing lines for high capacities, up to 300 T/hr. Part of this is a high capacity Tummers potato dryer which provides a storage time for the potatoes of approximately 2 weeks before use, when combined with ventilated bunkers.

Washing/Sorting including a Pintle belt.

The Tummers destoner/washing system is the most used systems for cleaning the potatoes and sorting out foreign materials. Since the potatoes are clean straight after receiving, it allows the customer to install optical sorting systems to take out colour defects and any unwanted products or materials that may remain in the product after washing. For potatoes with hollow hearts or low dry-solid contents a so-called brine bath is still the common way of removing these ‘ floaters’. To control the level of floatation, salt is added to the water, to make it denser. Recently many processors have made the decision to change from salt to clay as a medium since salt can have a high impact on extra wear and tear of the downstream.

Pintle Belt.

To remove potato vines from the flow, Tummers has experience with pintle belts, placed behind the washer. The conventional way is to have pintle belts prior to washing, but this has higher wear and can build up dirt on the belt, resulting in a poorly sorted result. Placing the pintle belt after the washer also creates the advantage of having a consistent condition of the product, it is always wet. When sorting in a dry environment, the clay and vines can vary from dry to wet, making it more difficult to tune the system.

To remove floating particles, such as corn-cobbs, plastics etc, Tummers has extended its range with the so-called active floating parts separator. This system allows the user to adjust an upwards water flow to remove even more light materials from the potato loads.

For more information:
Dwight Verhagen
Tummers Methodic
Tel: +31 ( 0 ) 164 614 070
Fax: +31 ( 0 ) 164 615 355
E-mail: dustin@tummers.nl
www.tummers.nl