Mono Belts for Balers

Balers are usually operated with four round belts, for example. However, under certain conditions these tend to run unevenly or even overlap, which can lead to expensive downtime. To address this problem, Continental has developed a spare-part solution that uses a single belt (mono belt) as a replacement for these four belts. The belt can be easily spliced endlessly on site without the need for a trip to the workshop or long downtimes, as this report on the successful pilot project describes.

Initial situation

In Niederwinkling, Bavaria, near Straubing, farmer Armin Reich runs a 30-hectare agricultural business as a sideline. The feed silage for his animals is a fundamental part of his business. For this purpose, he purchased a used Welger RP 435 master round baler. This machine has a variable baling chamber and individually adjustable baling pressure, and can produce bales with a diameter of 0.9 to 1.6 m and a width of 1.23 m. In this baler, four parallel belts are used as standard.

However, he also noticed disadvantages with the principle of four parallel belts:

• Depending on how long it is cut, a lot of grass falls between the belts and is lost. This reduces the feed mass per bale or requires more production time and therefore costs money.
• Selective pressure on individual belts – for example, on slopes or when driving over stones – can affect the tension of the belts to varying degrees. This reduces the precision of the baling process and results in deformed bales that are more difficult to transport and stack.
• Damage – for example, a small cut – immediately destroys the strength of the entire belt (unlike a mono belt, which is structurally less susceptible to damage from small holes thanks to its greater width).
• Parallel belts can tend to run over each other in spite of correct tension and roller adjustment. This leads to uneven operation and faulty baling, and can even cause the belt drive to jam – resulting in downtime and additional maintenance and repair costs.

An alternative is the single belt, known as the mono belt. It provides a much more even compression pattern for the bale and results in less loss in terms of material. It can also be controlled and adjusted with much greater precision.

The idea behind the project

Armin Reich therefore decided to convert his Welger baler so that it could operate with a mono belt. He approached his local specialist dealer with this request – and quickly encountered problems: although the mono belts were available as spare parts for various models, they were not available in the width required for the Welger baler. In addition, none of the available products were of OEM quality.

Reich therefore decided to purchase belt material from a wellknown original equipment manufacturer, cut it to the right length, and splice it as required. But this presented the next problem: the clamping technology was not suitable for splicing the belts, as the tensile forces that such a belt is subjected to during operation or dynamic shock loads are simply too high. The required vulcanization process would normally only have been possible in a specialist workshop and not on site, which again would have meant many hours of downtime.

In his search for a solution, Armin Reich was referred by his dealer to Peter Steer, Regional Sales Manager for Industrial Products at Continental. After an initial phone call, Steer understood the task at hand and immediately promised to find a practical solution.

Implementation: production

Peter Steer consulted with applications engineer Michael Möschen and the production team in Northeim, Lower Saxony. First, a few calculations were made. They came to the conclusion that proper vulcanization of this wider mono belt could be carried out in the shortest possible time and on site – i.e. practically on the farm – using standard vulcanization equipment. They also calculated that the design of a Continental belt would easily withstand the tensile forces that occur during operation, even after vulcanization.

It was then decided to produce such a belt as part of a test project. A period was found in which the production process could be changed at short notice – namely by eliminating the cutting of the finished roll into the narrower baler belts usually required for the aftermarket. The result was a baler belt approximately 120 cm in width. Thanks to the use of the standard production process, the technical specifications of the belt remained unchanged: a fabric layer is incorporated into the upper and lower layers made of high-performance elastomer. This consists of two outer layers based on polyamide and an inner layer based on polyester. “Both the longitudinal and transverse yarn have an S/Z twist,” explains Möschen, “which means that even the wider mono belt bulges less in the middle during operation and runs straight as an arrow.” Even sudden stretching under extreme loads – for example, when driving over a large rock – has practically no adverse effect on the belt. The individual fabric layers are additionally bonded together with a special rubber layer. This combination of materials ensures great flexibility and high durability. The tensile strength is > 450 N/mm. From the surface portfolio, a non-slip profile with a coarse fabric texture was chosen for the surface.

Implementation: assembly

Armin Reich found an experienced specialist company to carry out the vulcanization. It turned out that the wider mono belt could be spliced using the same steps as the narrower individual belts, namely: The entire process was completed by a two-man team and took around three hours.

1. Cutting the ends of the belt at opposite angles and separating the individual layers.

2. Cleaning and smoothing the surfaces

3. Applying the vulcanizing solution and intermediate rubber layers, including removing air bubbles and smoothing down any overlaps

4. Positioning on the vulcanizing press with lateral guides (to prevent any escape of the vulcanizing solution and deformation)

5. Vulcanization according to specific heating and cooling cycles

6. Finish with removal of vulcanization residues and protruding fabric fibers

1. TEST Cutting the ends of the belt at opposite angles and separating the individual layers.

2. Cleaning and smoothing the surfaces

3. Applying the vulcanizing solution and intermediate rubber layers, including removing air bubbles and smoothing down any overlaps

4. Positioning on the vulcanizing press with lateral guides (to prevent any escape of the vulcanizing solution and deformation)

5. Vulcanization according to specific heating and cooling cycles

6. Finish with removal of vulcanization residues and protruding fabric fibers

The result

After everything had cooled down, Armin Reich was able to run a successful test. The baling pressure, strength, and dimensional stability of the bales were highly impressive. He sums up the project as follows: "Long-lasting quality is really important to me, so I definitely wanted to use a mono belt from a wellknown brand. Since there weren’t any available for my baler, I am very happy to have found a partner in Continental that was able to respond to my specific requirements. At first, I was sceptical as to whether vulcanization on site would actually work quickly and without any problems, but everything went really smoothly. This is an important factor for us, as it meant we had minimal downtime and were able to get the machine back into operation quickly."

For Continental, too, the project was a complete success. Michael Möschen states: "Customer focus is always especially important to us at Continental. That's why we know there is strong market demand for wider mono belts as an alternative to classic round baler belts, and we therefore added a corresponding product to our aftermarket portfolio some time ago. Following this successful pilot project, we now know that vulcanization on site also works without any difficulties. We have accordingly decided to add these mono belts to our range as goods sold by length for belt splicing on site."

Technical data

Tensile strength	300–500 N/mm
Number of lengths	1–3
Length	100 m or individual lengths
Width	100–1,300 mm
Surface	Rough fabric texture Diamond profile Fine fabric texture Smooth Special versions available

PEP 450/3 60GS/GS