Forage harvester
The forage harvester is an agricultural device for picking up, chopping and loading crops such as grass , alfalfa or maize , especially when preparing silage or whole-plant silage . In addition, the device has recently become increasingly important for harvesting renewable raw materials . Another area of application is the chopping of straw. This is intended to achieve better properties when used as litter .
Types of forage harvesters
.jpg)
The forage harvesters can be divided into the following three main forms with regard to the design of the cutting elements (i.e. the chopping mechanism):
The usual cutting units have a working width of 6 meters.
- With the flail forage harvester, the already mown or not yet mown crop is picked up by flails, which are mounted on a horizontal rotating shaft arranged at right angles to the direction of travel, torn in the interaction of the flail shaft with a fixed counter-blade and fed through the ejection tower (chimney) accompanying transport vehicle is thrown. The advantage of the Schlegel forage harvester is its simple and robust construction, but it is disadvantageous that uneven ground can easily lead to contamination of the harvested crop due to soil that has been picked up.
- In the case of disc choppers, on the other hand, the crop is picked up either via a pickup or directly from the mower or maize header and fed to the actual chopper. The cutting and conveying onto the transport vehicle is done here by a disc equipped with knives and throwing blades, which rotates around a shaft in the direction of travel. The cutting length (the aim is four to twenty mm) can be regulated by changing the number of knives, the speed of the crop feed and the disc speed.
- With the drum forage harvesters, the crop is picked up either via a pick-up or directly from the mower or maize header and fed to the rapidly rotating chopper drum , which serves as a cutting and throwing element. The drum is arranged at right angles to the flow of material and is equipped with about 20 to 50 knives, which are also designed as cutting and throwing elements. The cutting length of the chopped material (also four to twenty mm) can be determined as with the disc chopper by changing the number of knives on the drum, the speed at which the harvested material is fed or the speed of the chopping drum. Modern self-propelled shredders have a cutting performance of up to 25,000 cuts per minute. When recovering forage maize, a processor is required behind the chopping drum, which squeezes the maize kernels and makes them digestible. Due to the limited throwing distance of the chopping drum, the shredded crop is thrown through the tower onto the transport vehicle by means of a post-accelerator.
A further distinction is to be made between self-propelled forage harvesters or forage harvesters attached to or pulled by a tractor in the front or rear, and sidecar forage harvesters mounted to the side of the tractor.
Further process chain
Usually, the chopped crop is loaded onto a transport vehicle driving alongside. These are usually tractors with trailers with a load volume of 30–50 m³. In some countries, trucks are sometimes also used as transport vehicles. The forage harvester can also load a trailer it has pulled itself (e.g. when driving through the field for the first time to create a transport aisle), with a special device for pulling a semi-trailer or a permanently attached bunker (e.g. for difficult soil conditions - the crop is handed over at the edge of the field ) are equipped.
When chopping (regionally also piercing ) a maize field, high concentration of the drivers involved is usually required. If the neighboring field cannot be driven on, for example because it has not yet been harvested, the transport vehicle cannot drive next to the forage harvester. The chopper's discharge tower is then swiveled backwards and the transport vehicle drives a short distance behind it. In the case of tractor-trailer combinations, if the tractor follows the forage harvester, the throwing distance must be sufficient to throw the crop over the length of the tractor. In some cases, it can therefore also be observed that the tractor-trailer combination is following the chopper in reverse, i.e. with the trailer directly behind the tractor. Sudden stops by the forage harvester driver due to obstacles or blockages quickly lead to rear-end collisions in both cases.
history
Forage harvesters are one of the youngest agricultural machines. Since their invention by Friedrich Segler (then Schlawe , later Quakenbrück ) in the 1940s, they have developed into high-performance machines and are currently considered the most powerful vehicle category used in agriculture. In earlier years, forage harvesters were mainly designed as PTO-driven attachments (mostly on the three-point hydraulic system , sometimes pulled) for tractors.
With the increasing spread of corn cultivation in northern areas and the rationalization of agriculture, the first self-propelled vehicles came onto the market in the 1970s. Initially the working width was around two meters with an engine output of less than 75 kW. In accordance with the increasing size of farms in agriculture, manufacturers offered ever larger machines; Maize cutting units with a working width of ten meters and engine outputs of up to around 850 kW are now available. With special equipment, forage harvesters are now also used to harvest energy crops (e.g. in short rotation plantations ). Due to the broader range of applications and the high requirements, even more powerful machines can be expected in the future.
Today around 2000 self-propelled forage harvesters are sold worldwide every year. The Claas company in Harsewinkel is the world market leader in the manufacture and sale of self-propelled forage harvesters . The largest chopper currently on the market is the Krone Big X 1180 with an engine output of 850 kW.
literature
- Horst Eichhorn (Ed.): Landtechnik . 7th edition, Ulmer Verlag, Stuttgart 1999, ISBN 3-8001-1086-5 , p. 405 ff.
Web links
Individual evidence
- ↑ Archive link ( Memento of the original from October 25, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Claas Field Shuttle
- ↑ http://rl.vdl.de/Journal_Digital/Schwerpunkt/2006/Schwerpunkt01_2006/hermann.php ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. VDL - mechanization in agriculture
