DLG e.V. - Test: Kuhn BC 2800 universal shredder

Kuhn BC 2800 universal shredder

Assessment – Brief Summary

The Kuhn BC 2800 shredder scored ‘very good’ and ‘good’ results in the test categories ‘quality of work, power requirement, handling, and in-field performance’. On account of these results the machine is eligible for the DLG APPROVED quality mark for the criteria mentioned above.

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Table 1: Overview of results

Test criterion Test result* Score**
Visual assessment of the quality of work
Consistency of chop lengths good +
Quality of work very good + +
Cross distribution of the mulched material good +
User assessments after field testing the machine
Attachment and removal good +
Access to service points good +
Cleaning before road transport good +
Side-shift function satisfactory
Occurrence of vibrations never + +
Stone impact protection good +
Cutting height control good +
Occurrence of blockages very rarely + +

*    The most frequently awarded grade
**   Grading system: very good (++), good (+), satisfactory (), not satisfactory (–)

Description and specifications

According to the manufacturer, the BC 2800 shredder is suitable for shredding stubble of silage maize, grain maize, break crops, grassland and Greening areas. The Kuhn BC 2800 shredder works at a width of 2.80 m and is attached to the tractor via a standard three-point headstock (cat. 2). The rotor is powered by a 1,000 rpm pto shaft.  The unit has a side-shift function that is controlled by a double-acting ram. This means that two hydraulic lines have to be coupled to the tractor.

The machine has curved skids on either side (photos 2 and 3) and stone guards at the front and a curtain at the rear which protect people from airborne stones and debris.

The shredder runs on two gauge wheels with pneumatic tyres which fold to the middle of the machine for compact road travel and storage in the shed. A stand supports the machine during removal from the tractor.

Further on, it has white reflectors on both sides and a plastic box to store tools and other items.
The plastic pto shield has a quick-fit mechanism which allows operators to attach and remove the shaft quickly.

The rotor is driven by a four-groove Powerband belt, the tension of which is checked by inserting a folding ruler in the slot on the belt guard.

The oil level in the gearbox is checked on the gearbox itself and takes an Allen key.
There are seven service points (one on either end of the rotor and the drive shaft, one on each gauge wheel and one on the headstock).

The base specification model is supplied with a cleaning tool to clean the machine before road transport, for example.

Figure 2: Kuhn BC 2800 shredder viewed from the left rear.

Figure 3: Kuhn BC 2800 shredder viewed from the side.

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Table 2: Kuhn BC 2800 universal shredder – Technical data

Description Kuhn BC 2800
Number of tool holders [No] 32
Number of tools [No] 32 hammer knives or 64 universal knives plus 32 stubble pallets
Weight per hammer flail [kg] 1.39
Weight per universal knife (3 elements) [kg] 2.45
Standard pto speed [r/pm] 1,000
Rotor speed at standard speed [r/pm] 1,758
Rotor diameter [mm] 647
Knife speed [m/s] 59

Figure 4: Kuhn BC 2800 shredder viewed from the front.

The Method

Measuring the quality of work and power requirement in grain maize stubble

The quality of work that is provided by the shredder is assessed by conducting field tests in line with the pertinent DLG test framework. The measurements are taken while the machine is shredding at usual groundspeeds in harvested maize fields that meet the testing requirements.

To document the conditions for the present test, the test engineers logged the crop variety and maturity stage, the type of soil and soil value number, the profile of the terrain, weather data, the tractor and com-bine harvester used as well as the header model, the stubble height and the amount of trash left in the field, the moisture level of the trash plus the weather on the day of the test.

The shredder was then set up according to the prevailing field conditions. This was done during extra runs before the actual test runs started.

The pto input was measured on a pto hub dynamo of the DLG Test Center. Forward speed and test course were measured with a Correvit L400 from KISTLER MESSTECHNIK. The fuel consumption was measured using DLG’s mobile fuel meter.

The height of the stubble left in the field after shredding was measured immediately after the test runs. These measurements were taken at a number of sample spots and involved measuring the height of that stubble that had been rolled over before shredding as well as stubble that had not been rolled over before the shredding pass.

After each of the three test passes some of the mulched material was sampled from a 1 m2 area and then exposed to gentle air drying. After that, it was fractioned by a drum sieve (Photo 5). The quality of work was assessed by a number of experienced farmers. These assessed the quality of work according to a four-stepped grading system: ‘very good’ / 
‘good’ / ‘satisfactory’ / ‘not satis­factory’.

The moisture of the material was measured gravimetrically at the lab after individual samples were taken during the shredding passes.

Measuring service time

The service work that was carried out by experienced and expert operators are listed below. While they were servicing the machine the time was measured with a stopwatch.

Greasing all grease points incl. the nipples on the drive shaft

The grease gun was next to the machine and readily at hand when clocking started. Each nipple received three shots of grease. After all grease points were attended, the operator replaced the grease gun on the ground next to the machine. This stopped the time taking.

Checking the oil level  in the main gearbox.

The necessary tool was readily at hand and placed next to the machine. The tester opened the oil plug and checked the filling level. Then he replaced the plug. Time taking was stopped when the operator had placed all necessary tools on the ground next to the machine.

Checking the belt tension

Again, all tools necessary to check the belt tension were readily at hand next to the machine. After the operator checked the belt tension, he placed all tools back on the ground next to the machine. This stopped the time taking.

Tensioning the belts

Again, the necessary tool was readily at hand next to the machine. After the operator tensioned the belt, he replaced the tool on the ground next to the machine. This stopped the time taking. As mentioned above, each check was repeated a number of times and by several persons. Then the individual measurements were averaged. All tools used for the tests are listed in the report.

Field testing the machine on user farms

The test machine was operated on a number of farms. After each operation, the operators had to fill in a questionnaire which comprised several questions on handling and quality of work. The operators answered the questions by check marking ‘very good’ / ‘good’ / ‘satisfactory’ / ‘not satisfactory’.

Figure 5: The material was fractioned by this drum sieve.

The Test Results in Detail

Measuring the quality of work and power requirement in grain maize stubble

In October 2015, the field test was carried out to determine the machine’s quality of work and power requirement. This function test was carried out in a field of grain maize (Pioneer P8745 variety, maturity stage K 250) which had been harvested two days prior to the test. The crop had been harvested by a New Holland CR 8080 axial-rotor combine with straw spreader and 8-row Cornstar 208 header from Kemper. The crop was about 1.80m tall at the time of harvest.

The test field was slightly sloping and the soil was sandy loam and the value number measured was 60. The amount of rainfall between planting and harvesting in the 2015 season was 201mm. The weather during the test was sunny with temperatures ranging between 12 °C and 21 °C.

The tractor was a 96 kW/131hp Steyr 4130 Profi CVT. Ground speed was 8 km/hr. The test involved measuring the quality of work and the power requirement while the machine was shredding the stubble using universal knives and hammer knives. Each test run was carried out three times.

In addition to the actual test field, the test machine also shredded the stubble on an adjacent smaller patch. This patch served for visual inspections of the quality of work which were conducted by five farmers.

Before the test started, the tester measured the length of 120 individual stalks that were sampled from the entire field. The stalk lengths ranged between 13cm and 29cm and the average length was 21cm. Another part of the test was to determine the amount of residues (plant residue including stubble) left in the field. The amount of fresh mass was 5.9 tonnes per hectare (with moisture rates ranging between 22.2 % and 37.7 %; the average rate is 27.7 %). The amount of dry mass was 4.6 tonnes per hectare. The amount of residues was small and the moisture level was low. The small amount of residues is primarily attributed to little rainfall in the growth period.

At the beginning of the test, the machine was set up during a number of runs that were not considered as test runs.

Visual assessment of the quality of work by five farmers

The shredder’s quality of work was assessed by five farmers who answered a number of questions on chop length, the overall quality of work, and the distribution across rows. The results are listed below:

Consistency of chop lengths

The consistency of chop length by the Kuhn machine was generally assessed as ‘good’. The consistency of chop length achieved by universal knives was generally rated as ‘very good’ and as ‘good’ by four farmers. The consistency of chop length achieved by hammer knives was rated as ‘very good’ by one farmer, as ‘good’ by three farmers and as ‘satisfactory’ by one farmer.

Quality of work

The farmers assessed the quality of work predominantly as ‘very good’. When the machine was fitted with universal knives, the quality of work scored a ‘very good’ from three farmers and a ‘good’ from two farmers. Universal knives and hammer knives received the same number of scores.

Distribution across rows

The distribution across rows achieved by the Kuhn shredder was mostly rated as ‘good’. When the machine was fitted with universal knives, it scored two ‘very good’ and three ‘good’ marks in the distribution across rows category. When the universal knives were replaced by hammer knives, distribution across rows scored one ‘very good’ from one farmer and four ‘good’ marks from four persons.

Measuring stubble height after the shredding pass

After shredding was completed, the height of the remaining maize stubble was measured. To do this, the testers measured 18 stubbles that had been rolled over by the tractor before the shredding pass and 18 stubbles that had not been rolled over prior to shredding. Photo 6 shows two rows of stubble where the trash was removed to expose the stubbles. The two rows of stubble on the left and right side had been rolled over by the tractor before shredding took place. The two rows in the middle were not rolled over.

Figure 7 shows the stubble height measurements. We noted that the stubble that was treated by hammer knives was shorter than that treated by universal knives. Overall, how­ever, the shredded stubble showed consistent lengths. After the test, we found that only very few stubbles in the bout had been rolled over and kinked so that they were not cut.

Figure 6: The stubble was shredded with universal knives and then swept with a brush to remove the trash. The maize stubble in the right and left passes was not shredded.

Figure 7: Average stubble lengths after shredding

Figure 8: Fractions of shredded maize stubble in percentages

Results of the fragmenting test

The sampled material was fragmented by a drum sieve. The moisture content ranged between 8.7 % and 9.5  %. The left column in figure 8 shows a slightly higher amount of small chops. This sample was taken from the bout that had been shredded with universal knives. The column also reflects a smaller amount of coarse chops which means that the universal knives shredded the crop residues to smaller chops than the hammer knives. The advantage of smaller chops is that they rot faster. As mentioned, the quality of work by all types of tools was predominantly rated as ‘very good’ after a visual inspection.

Power input results

Figure 9 shows the machine’s power requirement in two test versions, one testing universal knives and one testing hammer knives. Each test version involved three runs. The measurements were made with a pto hub dynamo. One column represents one run down one bout. The measurements were recorded during each run (pulse rate: 1 Hertz) and subsequently averaged. The averaged result is shown inside the graph above the three columns.

The power requirement during these test runs tended to be smaller when uinversal knives were fitted (54.0 kW) than when hammer knives were used (61.2  kW). Using universal knives, the machine required a power input of 63 kW in the first run and 49.6 kW and 49.4 kW in the second and third runs. The fact that the input was higher during the first run may be explained by a larger amount of organic material in that bout.

Servicing

The servicing times were clocked at the DLG Test Center for Technology and Farm Inputs in October 2015. The results of this function test is shown in table 3.

Figure 9: Power requirement during both test versions (universal knives and hammer knives), each version comprising three runs

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Table 3: Servicing times on Kuhn BC 2800 shredder

Test machine Tester Averaged result
1 2 3 4
Lubricating all seven grease points incl. those on the drive shaft [secs] 110 144 108 136 125
Checking the gearbox oil level [secs] 100 103 67 61 83
Checking the belt tension [secs] 18 12 11 14 14
Tensioning the belts [secs] 224 310 263 341 285

Greasing

It took the testers 108 to 144 seconds (125 secs on average) to attend all seven grease points. All testers were pleased about the fact that the plastic pto shield on the machine was very easy to remove, which means the pto shaft itself is easy to remove and attach.

Checking the oil level in the main gearbox

It took the testers between 61 and 103 seconds to check the oil level (average: 83 seconds). The only tool required for this is an Allen key.

Checking the belt tension

It took the testers between 11 and 18 seconds to check the belt tension (average time: 14 seconds). This is very easy by inserting a folding ruler in the slot on the belt guard. There is no need to remove the guard.

Tensioning the belts

Tensioning the four-groove Powerband belt took between 224 and 341 seconds in the test (hence 285 seconds on average). Kuhn BC 2800 offers the advantage that it is not necessary to remove the guard for tensioning the belt. All bolts and nuts are loosened with a 24” spanner, which eliminates the need to swap spanners during tensioning.

Practical test results on farms

The Kuhn shredder worked on five farms between the 24th September 2015 and the 20th October 2015 during which period, it shredded 60 ha of maize stubble and 2 ha of flower pastures. Table 4 shows the practical test results. In brackets, the number of farmers who gave their corresponding evaluation. Two questions were not answered by all farmers.

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Table 4: Practical test results

Assessing machine handling*
Access to service points
– Access to all seven grease points very good (2) and good (3)
– Access to the oil level plug on the gearbox good (5)
– Checking the belt tension very good (2) and good (3)
Attachment and removal
– Drive shaft storage very good (4) and good (1)
– Plastic caps on hydraulic couplers very good (1) and good (3)
– Accessibility during attachment/removal very good (1) and good (4)
– Access to the stand very good (2), good (1) and satis­factory (1)
– Adjusting the stand on the mounted machine very good (1) and good (3)
Cleaning for road transport good (5)
Side-shifting mechanism very good (1), satisfactory (3) and not satisfactory (1)
Occurrence of vibrations never (5)
Stone impact protection good (5)
Cutting height control good (3) and satisfactory (2)
Assessing the quality during practical tests*
Occurrence of blockages never (4), occasionally (1)
Quality of work in practical tests very good (2) and good (3)
Distribution across rows very good (1), good (3) and satis­factory (1)

*    The figures in brackets indicate the number of farmers who gave this mark

Summary

This DLG test confirms that the Kuhn BC 2800 shredder is suitable for shredding grain maize. The machine passed the quality of work test by scoring ‘very good’ and ‘good’ results. Farmers assessed the quality of shredded maize as ‘very good’ and ‘good’ as well. The machine’s power requirement was 54.0 kW when shredding maize stubble with universal knives and 61.2 kW when using hammer knives.Machine handling during operation was predominantly assessed as ‘very good’ and ‘good’ by the testing farmers.

These test results confirm that the Kuhn BC 2800 shredder is eligible to receive the DLG APPROVED quality mark (for the test categories ‘quality of work and power requirement, handling, and in-field per­formance’).

DLG Test Center Technology and Farm Inputs

DLG e.V.
Max-Eyth-Weg 1
64823 Groß-Umstadt
Germany
Tel.: +49(0)69 24 788-611
tech(at)DLG.org

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A "DLG Approved for single criteria" test mark is awarded to agricultural engineering products, which have successfully passed a DLG smaller-scope usability test based on independent, recognised criteria. The tests serve to highlight particular innovations and key criteria in the test object. The test may include criteria from the DLG testing framework for overall tests or may focus on other determining features and properties of the test object. The minimum requirements, the test conditions and procedures and the assessment criteria for the test results are determined in agreement with a group of DLG experts. They equate to the accepted rules of engineering and scientific and agricultural expertise and requirements. A successful test concludes with the publication of a test report and the award of the test label, which is valid for five years from the date of award.

The universal shredder Kuhn BC 2800 entered the DLG test on “Quality of work, power requirement, handling and in-field performance”. The test explored the machine’s quality of work in grain maize stubble and ease of servicing. To assess the latter, the machine was serviced by four experienced and expert farmers and the time intervals were measured with a stopwatch. Service and maintenance included the following operations: Greasing all grease points, checking the gearbox oil level, checking and correcting the belt tension. To assess in-field performance, the machine was operated on five farms where all farmers filled in a questionnaire after ­operating the machine, answering questions on general machine aspects as well as the quality of work. No other criteria were tested  in the present test.

Manufacturer and applicant

Manufacturer:
Nobili S.P.A.
40062 Molinella (Bologna)
Italy

Applicant:
Kuhn Maschinen-Vertrieb GmbH
Schopsdorfer Industriestraße 14
39291 Genthin, Ortsteil Schopsdorf
Germany

Test Execution

DLG e.V.,
Test Center
Technology and Farm Inputs,
Max-Eyth-Weg 1,
64823 Groß-Umstadt
Germany

DLG Testing Framework
DLG testing framework for shredders

Field
Technology in outdoor operations

Project manager
Dr. Ulrich Rubenschuh

Test engineer(s)
Dipl. Ing. agr. Georg Horst Schuchmann  *

* Reporting engineer