Cleaner Technology Projects in Denmark 1997
Investigation of the Influence 3 Harvesting Modes Have on the Subsequent Cleaning of Beets
Undersøgelse af 3 optageprincippers indflydelse på den efterfølgende rensning
af sukkerroer
Arbejdsrapport nr. 40, 1997, Miljøstyrelsen
The purpose of the experiments in 1996 was to investigate whether the harvesting principle influences the subsequent cleaning of the beets by brushes and compressed air (standard cleaning), and to find the amount of stone (and size distribution) to be lifted by each individual harvesting mode.
During the 1996 campaign field tests with 3 harvesting modes in Sweden and 2 in Denmark were made: Oppel wheels (TIM), belts (Armer), oscillating shares (Edenhall). Besides, the cleanability of 4 varieties lifted by Armer in 2 fields (light and heavy clay soils) in the neighbourhood of Danisco Seed were compared.
The harvesters were changed so that only one row was lifted, and the material was left on the soil behind the harvesters without any cleaning. For the investigations on amount of stone, a plastic film was unrolled on the soil behind the harvesters for deposit of the lifted material.
The beets were cleaned in a stationary cleaning station in the field on the day of harvesting, and the beets from each harvester were given the same cleaning. The first cleaning was done in a module with rubber finger rollers and the second cleaning in a module with brushes. In the module with brushes the beets were cleaned only once, and the second time by brushes and compressed air. For determination of residual soil the beets were blown clean by compressed air pistols. The residual soil is expressed as the percentage of clean beets without beet crowns.
Cleanability: The results are divided into 2 main groups based on the type of soil: Light clay soil and heavy clay soil.
 | Generally there has been a high level of soil on the harvested beets (50-100% on clean beet). With regards to light clay soil, by standard cleaning the beets could be cleaned to a level of 2.7-5.3% residual soil on clean beet, and at heavy clay soil to 17.7-25.3% residual soil. |
| In none of the two types of soil was seen any essential difference in cleanability of beets from oppel wheels (TIM), belts (Armer) or oscillating shares (Edenhall) was seen. |
| On heavy clay soil the final soil is proportional to the starting soil. On light clay soil the final soil is independent of the starting soil. |
Stones: Harvesting by belts (Armer) results in considerably fewer stones than harvesting by oppel wheels (TIM) and oscillating shares (Edenhall). Expressed in percent of beets it can be calculated that by oppel wheels 0-22% stone (>50 nun) on beets are drawn up (the highest level on stony fields in Sweden), by Armer 0-0,04% and by oscillating shares 3.5-10% on beet (measured on stony earth). The results show a considerably higher risk of stones to the factory from oppel wheels than from belts (Assumption: Stones <50 mm are separated in beet harvesters).
Varieties: For each variety of beets the residual soil is nearly doubled by a change from light to heavy soil. It is not possible to distinguish between the varieties K1428 and D5502 and between Marathon and Lacta. However, there is a tendency that cleaning by Marathon and Lacta results in a lower residual soil than K1428 and D5502.
Cleanability: The tests have shown that the harvesting principle is of no importance for the residual soil (= cleanability in a standard cleaning).
Stones: From a stone point of view harvesting by belts (Armer) should be preferred to harvesting by oppel wheels.
Varieties: The effect on cleanability of changing the type of soil is greater than the effect of changing the variety of beet.
Author/ institution
Flemming Hansen, Bjarne Fallesen og Franck B. Hansen
Danisco Sugar
This report is subsidised by the National Council for Recycling and Cleaner Production
ISSN no. 0908-9195
ISBN no. 87-7810-795-4