Retrofit – special elevators for potatoes

This was a modernization of an existing plant. In two different plants, worn and aging elevators were to be replaced with new ones.  The production of potato starch is an extremely precise process that begins with the cleaning of the potato. In an oversized washing drum, the freshly delivered potatoes are thoroughly washed and then lifted over the elevator into a grater. The lifting is implemented by means of elevators, but the connection between the washing drum and the elevator takes place in a waterway. The elevator has an inlet of approx. 1200 x 1200 mm, which is located at a height of approx. 2 meters. The waterway flows directly into the elevator base, which is approx. 2 meters below water level. The requirements for the machines were therefore high: 120 tons / hour capacity, waterproof elevator foot, waterproof components, production from stainless steel, special elevator buckets, static calculations and a complete special construction. In addition, the elevators run for about 7000 operating hours and convey 750,000 tons of potatoes annually.

Due to the 100 years of experience across the industry, Zuther was awarded the contract and was allowed to develop and produce the special structures and was also responsible for the lead assembly. After the detail engineering and the development of the elevators, the production in stainless steel started. Besides the challenge of the special buckets, which was realized by a braced construction, it also had to be ensured that all floating potatoes could be picked up. The water level inside the elevator must remain at the same level at all times. Therefore, in addition to the water drainage, Zuther also installed a fresh water supply, which is automatically controlled. All installed components were designed to be waterproof and the entire construction was waterproofed. The Zuther stuffing box reliably seals the shaft of the lattice bar drum. The elevator’s motor is equipped with a fluid coupling to ensure smooth and wear-free starting. In addition, the entire elevator is lined with PE1000 from the inside to prevent wear here as well, since there is only 5-10 mm of air between housings. There are several maintenance doors inside the elevator. Some of the elevators were pre-assembled in the factory and implemented in the process within one day.