Ground nut decorter

1. Ground Nut
(Groundnut, Peanut, Monkeynut, Earthnut,
Manilanut, Palli)
Scientific name :- Arachis hypogaea
(ఆరచిస్ హ
ై పోజీయా)
family :- legumes

6. ◆ 12-14 members
using to harvest in
1 day per hectare.

15.  Both digging and shelling of groundnuts present a great problem in making the product ready
for market.
 The process of obtaining kernels from the stripped groundnut pods is known as
decortication.
 Mostly decortication is usually done by breaking the shell by hand pressure under the thumb.
Manual decortication by hand is laborious, expensive and less productive. But now, the
commercial hand and power operated groundnut decorticators are being used in the country.
 Both these machines work on the same principles. The main difference lies in their
capabilities. After decortication, separation of grain from a mixture of grain and split shells is
done in an air stream.
 The separation is achieved by allowing the air stream created artificially or naturally and
passing the mixture vertically down, perpendicular to the air blast. The grain being heavier
gets collected almost at the place of dropping, whereas the lighter material (split shells) is
blown away to a greater distance.
 The hand operated one has a capacity of about 200 kg/h and the mechanical decorticator has
500 kg/h capacity.
GROUNDNUT DECORTICATORS

16.  The groundnut decorticators are classified into two types based
on source of power:
 (1) Manual type
 (2) Power operated
 Manual type groundnut decorticators are further classified into:
 (a) Hand operated rotary decorticator
 (b) Pedal operated rotary decorticator.
 (c ) Hand operated ‟‟ rocking type‟‟ decorticator.

17. Hand operated rotary type decorticator
It consists of a wooden or cast iron shelling drum and a
steel grate. Shelling of the nuts is accomplished in the
clearance between the drum and the grate. The output of
the machine is 0.4 to 0.6 quintals of pods/hour.

18. Pedal operated rotary type decorticator
 It is operated by foot. The motion from the foot pedal is transmitted to the
cylinder through a connecting rod and a set of spur gears. This machine
provided with a fan. The fan is operated by means of pulley mounted on the
cylinder shaft. The kernels are separated from the shell by the winnowing fan.

19. Hand operated ’’rocking type”
decorticator
 It consists of the following parts: (a) angle iron frame, (b) trough of radius 28 cm
(c) steel handle, and (d) beaters.
 The beaters are fixed to the handle at the bottom and operate in to and fro motion.
The pods are put into the trough and the handle is operated to and fro to
decorticate the pods. The decorated pods are collected beneath the through. It
requires two persons to operate and can shell 1 to 1.25 quintals of pods/hour. It
can also be run by a small 1.5 Hp engine.
Hand operated rocking type decorticator

20. Power operated rocking type decorticator
 A power operated groundnut decorticator require 8 hp engine to shell about 75 to 80 bags (
1875 to 2000 kg ) of groundnut per hour.
 The machine has to perform the following functions:
 (a) Feeding of groundnuts to the shelling unit,
 (b) Shelling of groundnuts and separating nuts from the shell and
 (c) Cleaning the nut from the mixture.

21. •It consists of the following main parts: Feeder
mechanism, Shelling unit and Crushing section.
•The feeder mechanism consists of a hopper,
feeder shaft and pawl and ratchet wheel to drive
the shaft. Groundnuts are fed to the machine at a
uniform rate. Feed rate can be varied by adjusting
the stroke of the pawl.
•The shelling unit is provided with two main
parts, namely crushing plate and a grate. The
crushing plates are made of close grained semi
steel. Six small externally grooved channels are
mounted on radial arms of the main rotor shaft
which rotates at about 110 rpm.
•As the main rotor shaft is operated, the external
grooved surface channels, roll and shell
groundnuts.

22.  The crushing plates are bolted to the externally grooved channels and mounted
at an angle resulting in unequal gaps on both ends between the plates and the
grate.
 The minimum uniform gap of 2.5 to 3.2 cm between the lower edge of the
plates and inner surface of the great gives satisfactory operation.
 The grate is composed of a flat steel bars placed horizontally on their edges
with a small space between the bars can be done by changing the thickness of
the washers used on them, to suit any size of pods.
 A fan, which is operated at 450 rpm by the main rotor shaft, is the basic part
of the cleaning section.
 The blades of the fan are made of iron sheets bolted to angle iron arms on both
sides.
 The blast of air created by the fan is strong enough to blow away the broken
empty shell, so that the heavy nuts fall into the bottom pan by gravity.

23. Power operated rocking type decorticator