2023 gold manus® – coulter

• What was needed: iglidur ® plain bearing
• Requirements: Corrosion-free bearing points, problem-free contact with liquid nitrogen fertiliser, long service life despite oscillating movements, no use of lubricants
• Industry: Agricultural engineering

Many farmers use injection fertilisation to ensure that maize, potatoes and wheat grow well. This involves the use of ploughs that open up the soil so that liquid nitrogen fertiliser flows close to the plant roots. J&M Manufacturing is one of the manufacturers of these agricultural machines. The US company has developed the NitroGro applicator. It works as follows: A tank for liquid nitrogen is mounted in the centre of a tractor trailer. Two booms can be folded out to the right and left, either nine or 18 metres long depending on the model. The centrepiece of these wings: up to 37 so-called para-linkage coulters, which bring the nitrogen into the soil in a targeted manner and with a low loss rate.

In order to design the new applicator for nitrogen fertilisation more economically than competitor models, the engineers at J&M Manufacturing decided to use an alternative to classic bronze bushes for the system's pivot points. In doing so, they have tackled a problem that many farmers are concerned about: greasing the plain bearings. Despite grease nipples, which continuously supply the bearing points with grease, relubrication involves considerable effort. Austin Franz, design engineer at J&M Manufacturing, estimates that it takes up to 52 minutes to apply grease using a 25-row applicator with five grease nipples per row. Almost an hour is lost every day before work can even begin in the field. A loss that translates into lower yields and profits. "In this time, not even including the additional time for changing grease hoses and other things, a farmer could work a large area," Franz is convinced. "A farmer driving 13 kilometres per hour with a 25-row applicator can fertilise around one hectare of land per minute." Without lubrication, he could therefore manage 52 hectares more per day. 520 additional hectares in ten days. "Far more than the nitrogen application of one day."

In order to do without lubrication, the designers at J&M Manufacturing used polymer plain bearings from the iglidur® G series from motion plastic specialist igus® at all five pivot points of the coulter. The highlight: microscopically small solid lubricants are integrated into the high-performance plastic, which are released during operation and enable low-friction dry operation without a drop of grease. Lubrication is therefore no longer necessary. As a result, farmers can get to work faster. In addition, the polymer bearings are predestined for use in the field. While the lubricating film of metal bearings often becomes a dirt magnet and combines with dust and dirt to form a mixture that negatively affects the smooth running of the bearing, polymer bearings are resistant to dirt. They are also environmentally friendly as there is no risk of contamination, corrosion-free and resistant to media and temperatures. Franz assumes that the applicators with polymer bearings from igus® will last at least seven years in the field. "This is the second year we have been offering them. Over 95 per cent of the shares we have sold are para-linkage shares with igus® polymer bearings."

With the polymer bearings from Cologne, the engineers at J&M have also succeeded in realising a spring-loaded system with a parallel design in which the knife and blade remain parallel to the ground at the same height when engaged. Compared to the industry standard, where the knife is located behind the share and swings upwards out of the soil faster than the blade, this has the advantage that hardly any fertiliser can evaporate into the atmosphere. An important point. This is because nitrogen turns into nitrous oxide and acts as a greenhouse gas. "The only option on the market was quite expensive. The main aim of the design was therefore to build a coulter that reduces the loss of fertiliser through volatilisation at a reasonable cost," the J&M designer continues