Grain SA August 2017

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Cut losses with PRECISION
Plant with VISION
Process Monitor
for Air Seeders
‡ Area
‡ Speed
‡ Tacho up to 4 axles
‡ Alarm on each function
‡ Easy to install
‡ Bin / Tank full
‡ Bin / Tank empty
Proudly Made
in South Africa
Tel: 012 345 3193
Fax: 012 345 6763
Web:
Email:
Sales:
Planter Monitor
‡ Seed per 100m per row, seed population
‡ Hectares worked and much more
‡ Easy to install and maintain
‡ Fertiliser and turning of axles
‡ Can be applied to most planters
‡ Real tough, rust and water resistant
Several tests have already been done on different soil types and it
has been found that not all rip actions are effectively done. The ef-
fectiveness of the ripping depends largely on the soil type, soil clay
percentage and moisture percentage. The mechanical differences
will, of course, depend on the working depth, working speed, shear
type and shear cutting angle.
Photo 1 is an example of an inefficient rip operation where the soil
is not properly loosened. Photo 2 shows an effective ripping pro-
cess because the volume of soil is more effectively loosened. Thus,
the amount of energy used to do the work is better utilised.
Drawbar power needed for rippers
The pulling force required for rippers is generally very high, but will
depend on the soil type, ripper teeth design and shear design. Of
course, the ripping depth will also play a role. The question is, what
is the optimal working depth because the deeper the ripping action,
the higher the power demand.
Ripping depth will depend on the specific need, whether it is to
break a plough-pan, or because of very sandy soil which need to be
ripped every year because of the characteristics of the soil.
Shear design, shear working angle, shear width and placement of
shears will also have an effect on the energy consumption. Tests
have been done with different shear angles versus the drawbar pow-
er required.
It was found that the higher the shear angle with the horizontal, the
higher the drawbar power needed because of more soil disturbance
taking place at higher shear angles.
Implement efficiency improved rapidly by increasing the ripper
shear angle on the ripper tine. This is due to the fact that better and
more efficient loosening of soil takes place. Again the amount of
drawbar power is better utilised.
Spring tension setting of the ripper tine
Some rippers are designed with an auto release mechanism on the
tines which operate against a spring tension. The purpose of the
ripper tine spring is to safeguard the ripper tine when hitting a rock
or hard pan in the field.
The spring tension setting will normally vary according to the soil
type and conditions. It is important to check the ripper manufac-
turer’s manual and set it accordingly. When the setting is not cor-
rectly done it may either damage the ripper tine or have an impact on
ripper depth control.
Conclusion
When a sub-soiler or ripper needs to be utilised, the following
factors can be considered with regards to the operational efficiency:
Optimal traction efficiency of the tractor.
Different types of soil such as sand, clay, loam or combination of
different components.
Soil physical properties such as moisture content and bulk
density.
Number of ripping shanks.
Plough-pan and optimum ripping depths.
Shear design parameters such as shear working angle, shear
width and placement of shears.
Make sure to correctly set the spring tension on the ripper tines
for correct operation purposes.
Contact details
Information regarding this article on test results is avail-
able from ARC-Agricultural Engineering. Contact Johan
van Biljon at or 012 842 4000 or
Dr Tingmin Yu at or 012 842 4090.
1: An example of
inefficient ripping.
2: Efficient ripping.
1
2