This presentation consists of descriptions regarding different types of metering devices with appropriate figures.

1. Seed metering devices
Vijitha Vikneshwaran
Lecturer(Temporary)
Faculty of Technology
University of Jaffna

2. Introduction
• Seed metering devices will meter the seeds at their
desired depth
desired location
desired pressing
• It can be classified into
Bulk seed-metering device
Single seed hill metering device
2

3. Bulk seed-metering device
• It draws seeds in bulk, delivers them at the desired rate
in seed tube for sowing
• There are 4 types
1. Stationary orifice with agitator
• Low cost
• Size of the orifice is controlled by sliding plate
• Consequently the seed rate also will be controlled
3

4. 2. Flute roller
• Widely used in seed drills
• Made of cast iron, aluminum or plastic
• Handles wheat, gram, green gram, soybean and sorghum
seeds
• Seed rate is controlled by exposure length of roller
Bulkseed-meteringdevice,cont…
Fluted roller
Figure 01: Fluted roller metering device
4

5. Bulkseed-meteringdevice,cont…
Seed entry
Seed exit
Drive shaft
Seed dropper housing
Adjustable flap
Sliding cut-off
Sliding the shaft adjusts roller
exposure to the seed
Fluted roller
Figure 02: schematic diagram of fluted roller metering device
5

6. 3. Stud type roller
• Widely used in European design seed drill
• Studs are present on the periphery
• Application rate is changed by multi speed gearbox
Bulkseed-meteringdevice,cont…
Figure 03: Stud type roller type metering device
6

7. 4. Rotating drum with orifice type
• Popular for paddy crop
• Consists of a horizontally positioned cylinder drum
• The drums have rows of closely spaced holes punched
along the periphery
• Seed rate depends on the size of holes in the drum
Bulkseed-meteringdevice,cont…
7

8. Bulkseed-meteringdevice,cont…
8
Figure 04: Rotating drum with orifice type metering device

9. • Seeds are soaked prior to sowing
• And then soaked seeds are put into the drums
• Then the seeds are allowed to fall on the field which
posses some amount of moisture (muddy condition)
• Therefore the seeds can be positioned perfectly at same
row to row spacing
• It is possible to get more yield through this device
• This is an effective method compare to energy spent in
transplanting
• Any how seed weed growth is slightly high in this method
Bulkseed-meteringdevice,cont…
9

10. Single seed hill metering devices
• Design to maintain uniform seed spacing
• There are 06 types
1. Vertical roller with cell metering device
• Good for very small seeds like mustard and jute
• Rotor is positioned vertically at the base of the seed
hopper
• Seeds are picked up into the cells and are dropped one
by one
10

11. • The vertical plate will have small holes on the periphery
• As this rotates the seeds will be picked up within the cup
• Then the seed delivery will take place
11
Singleseedhillmeteringdevices,cont…
Seed delivery tube
Vertical plate
Seeds
Seed box
Figure 05: Vertical plate metering device

12. 2. Horizontal plate-metering devices
• Commonly used for maize
• Wide range of plates with varying size and number of cells are
provided for different seeds
Singleseedhillmeteringdevices,cont…
12
Figure 06: Horizontal plate-metering device

13. • Plate has seed holding cups or seed holding locations and
that rotates
• The outer ring carries a cut-off devices and a knock out
devices
• Cut off device will brush up the extra seeds
• Knockout device will knock the seeds exactly at the
location where it has to go into the seeding tube.
Singleseedhillmeteringdevices,cont…
13

14. 3. Inclined plate metering device
• Commonly used for sowing of legumes, sorghum and
peanut
• Easy construction
• The inclined plate rotates at an angle of about 60 ̊ with
the horizontal
• Inclined structure provides smooth movement of seeds
• Seeds are picked in the cells and dropped on the top of
inlet of seed tube
Singleseedhillmeteringdevices,cont…
14

15. Singleseedhillmeteringdevices,cont…
15
Cell
Hopper
Base plate
Bevel gear
Sliding baffle
Seed metering plate
Seed tube
Chain drive
Ground wheel
Figure 07: Inclined plate metering device

16. 4. Belt with cell-type metering device
• Metering hole is provided at equal spacing on an endless
belt.
• Once the seed is trapped and comes to the location, it
will be knocked off at that place in the seed tube.
• The belt can be changed according to the seed type.
• Seeds from the main hopper enter a small chamber
above the metering belt and remain at controlled level.
• Then the seeds are delivered in the furrow close to the
ground with small terminal velocity to achieve
appropriate spacing.
Singleseedhillmeteringdevices,cont…
16

17. Singleseedhillmeteringdevices,cont…
17
Metering belt
Figure 08: Belt with cell-type metering device

18. 5. Cup feed metering device
• It is used where seed damage due to rough mechanical
handling is not desirable
• It is applicable for planting of garlic, cloves and sugarcane
buds
• Size of the spool depends upon the size of seed
• Seed rate depends on number of spool and rotational
speed.
• Size of the cup can be changed depending upon the size
of the seeds.
Singleseedhillmeteringdevices,cont…
18

19. Singleseedhillmeteringdevices,cont…
19
Figure 09: Cup feed metering device
Cup-feed type metering mechanism
Metering chain

20. Singleseedhillmeteringdevices,cont…
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Figure 10: Schematic diagram of cup feed metering device
Hopper
Shutter
Cup disk
Delivery tube

21. 6. Pneumatic metering device
• Uses air suction for picking the seeds
• Aspirator blower is used to create a pressure of 3-5 kPa
in the blower inlet chamber.
• Blower inlet chamber is connected to the vacuum disc of
the planter unit.
• Seeds are moved up and released when the pocket pass
a baffle that cut the vacuum and drop seed into furrow
by gravity.
Singleseedhillmeteringdevices,cont…
21

22. • Pneumatic metering device has,
99-100 % cell fill efficiency
99-100 %single seed picking efficiency
Less or no damage of seeds
22
Singleseedhillmeteringdevices,cont…
Figure 11: Pneumatic metering device

23. Calibration of seeders
The procedure of testing the seed drill for correct seed rate is
called calibration of seed drill.
It is necessary to calibrate the seed drill before operating in
the field to get a predetermined seed rate of the machine.
The following steps are to be followed for calibration
• Step 1: Determine the nominal width (W) of seed drill.
𝑊 = M × 𝑆
Where,
M - Number of furrow openers
S - Spacing between the openers (m) 23

24. • Step 2: Find the length of a strip (L) having nominal width
(W)
𝐿 = (
10000
𝑊
)
=
10000
𝑊
𝑚
• Step 3: Determine the number of revolutions (N) the
ground wheel has to make to cover the length of the strip
(L)
π × 𝐷 × 𝑁 = (10000/𝑊)
𝑁 = (
10000
π𝑊𝐷
) rpm
Where,
D - diameter of ground wheel (m)
Calibrationofseeders,cont…
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25. • Step 4
Raise (Jack) the seed drill in such a way that the ground
wheels turn freely.
Make a mark on the drive wheel and a corresponding mark at
a convenient place on the body of the drill to help in counting
the revolutions of the drive wheel
• Step 5
Fill the selected seed in the seed hoppers.
Place a sack or a container under each boot for seeds
Rotate the twenty revolution of ground wheel
25
Calibrationofseeders,cont…

26. • Step 6
Replicate the same procedure minimum three times
Calculate the mean weight of seeds collected into the container
• Step 7:
Calculate the seed required (kg/ha)
Seed rate = (N/20)* mean weight of seed collected in 20
revolution
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Calibrationofseeders,cont…

27. THANK YOU
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