Notes on Vibrating Feeder used in bulk material handling

1. P R E P A R E D B Y
J I S H N U V
E N G I N E E R , B H E L - I S G
VIBRATING FEEDERS

2. 1.INTRODUCTION
 A vibrating feeder is a feeder/material conveying
equipment consisting of a pan or trough to which a
vibrating motion is imparted so that the material is
impelled in a definite, controlled flow.
 Normally, it is positioned under the opening in the
bottom of a bin or below an emergency reclaim
hopper in a stockpile
 Generally its use should be avoided where the
material is of sticky nature and which has the
tendency to build up on the surface of pan/trough

3. 2. TYPES OF VIBRATING FEEDERS
 Vibrating feeder can be classified into two types
based on the vibration imparting mechanism
 2.1) Direct force exciter type
 Direct force exciter (DFE) type vibrating feeder
consists of an unbalanced weights assembly which
imparts vibration to the trough due to the centrifugal
force while rotating
 The counterweights of the DFE are positioned in
such a way that the unbalanced weights create
transverse as well as longitudinal vibration of stroke
sufficient to convey the material

4. 2. TYPES OF VIBRATING FEEDERS
 2.1.1) Constructional details of a DFE vibro-
feeder

5. 2. TYPES OF VIBRATING FEEDERS

6. 2. TYPES OF VIBRATING FEEDERS
 Trough/pan/deck is the tray on to which the
material is fed from the hopper/bin. It consists of a
mother plate (IS-2062 Gr-B/ST-42) and liner (SS-
409M/Tiscral/SAILHARD) fixed on to it. The liners
are fixed on to the mother plate normally using
countersunk bolts and are torque tightened.
 Direct force exciter:- Direct force exciter imparts the
vibration to the deck due to the centrifugal force
generated by the rotation of unbalanced weights.

7. 2. TYPES OF VIBRATING FEEDERS

8. 2. TYPES OF VIBRATING FEEDERS
 The centrifugal forces F1 and F2 add to the resulting
centrifugal force F, which produces linear
oscillations. The stroke/amplitude and thereby the
material flow rate are adjusted by varying the
number of additional weights

9. 2. TYPES OF VIBRATING FEEDERS
 Cardan shaft is a universal joint shaft which permits
axial as well as radial displacement.
 Spring (Front and rear):- MOC of the spring
commonly used is 50CrV4 or 55 SI7 or EN-45A

10. 2. TYPES OF VIBRATING FEEDERS
 2.2) Unbalanced motor type
 Unbalanced motor type vibrating feeder consists of 1 or 2 unbalanced motors
which impart vibration to the vibrating feeder
 There are two methods of mounting of the unbalanced motors:
 2.2.1) Side mounting:

11. 2. TYPES OF VIBRATING FEEDERS
 2.2.2) Back mounting

12. 3. CAPACITY CALCULATION OF A VIBRATING
FEEDER

13. 3. CAPACITY CALCULATION OF A VIBRATING
FEEDER
 Material flow rate Q= ρ x A x V x 3600 x IF
 Where
 ρ = Density of the material conveyed in t/m^3
 A= Cross sectional area of the material bed formed in m²
 V= Flow velocity of the material in m/s; Minimum to be
maintained is
 A= B x D; B is the width of the tray over which the material bed
formed/ inside skirt width; d is the throat opening height or
skirt height at discharge side.
 IF= Inclination factor depending on the angle of inclination

14. 3. CAPACITY CALCULATION OF A VIBRATING
FEEDER
 Solved example.1
 Design TPH:- 720TPH
 Material conveyed:- Coal
 Skirt height at discharge= 630mm
 Inside skirt width= 1580mm
 Flow velocity of material= 0.25m/s
 Angle of inclination of the tray w.r.t horizontal=12 ˚
 Soln) Q= ρ x A x V x 3600 x IF
 ρ = 0.8t/m^3
 A= B x D= 1.58 x 0.63= 0.9954m²
 V= 0.25m/s
 IF=1.3
 Q=0.8 x 0.9954 x 0.25 x 1.3 x 3600=931.6944tph>720 tph
 Hence capacity selection of the model is ok

15. 3. CAPACITY CALCULATION OF A VIBRATING
FEEDER
 Solved example.2)
 Design TPH:- 500TPH
 Material conveyed:- Coal
 Skirt height at discharge= 750mm
 Inside skirt width= 1500mm
 Flow velocity of material= 0.25m/s
 Angle of inclination of the tray w.r.t horizontal=10 ˚
 Soln) Q= ρ x A x V x 3600 x IF
 ρ = 0.8t/m^3
 A= B x D= 1.50 x 0.75= 1.125m²
 V= 0.25m/s
 IF=1.2
 Q=0.8 x 1.125x 0.25 x 1.2 x 3600=972TPH>500 tph
 Hence capacity selection of the model is ok

16. 4. MOTOR SELECTION OF A VIBRATING FEEDER
 Power required for driving a vibrating feeder, P=
(VW x a x N x 1.25)/(97400 x LRT)
 Where
 VW= Vibrating weight in kg
 a= Amplitude of vibration in mm
 LRT= Locked rotor torque ratio
 N= RPM of the feeder
 P is in kW

17. 4. MOTOR SELECTION OF A VIBRATING FEEDER
 Solved example.3)
 Vibrating weight:- 2600 kg
 Amplitude of vibration:- 4mm
 RPM of motor:- 1000RPM
 Starting torque maximum 2.0 times normal
 Motor selected:- 11kW
 Soln)
 VW= 2600kg
 a=0. 4cm
 N= 1000 RPM
 LRT= 2.0
 P= (2600 x 0.4 x 1000 x 1.25)/ (97400 x 2)=6.67kW
 Motor selected is 11kW. HENCE SELECTION OK