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PO Box 610, Morley WA 6943
22 Donna St, Morley WA 6062
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Conveyor Design, Conveyor Dynamic Analysis, Belt Conveyors, DEM Chute Design,
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Helix delta-T Conveyor
Design - Feeder Calculation - Theoretical Method
You can calculate the additional forces required to pull
material out of a hopper or bin. Select the Calcs, Calculate Feeder Loads
from the main form. The following form will be displayed:
This form allows you to calculate the Additional Tension required to pull a material out
of a feeder, bin or hopper. This additional tension is mainly due to the shearing action
required to pull the material out of the hopper opening. The method used here is the
'Theoretical' method developed first by arnold and McLean and the then refined by A.W.
Roberts and others. Many papers have been published on this subject and some are quite
complex, however, Helix have refined the inputs to those shown in this form. The material
in the feeder will require testing in order to determine the wall frcition and effective
angle of internal friction.
The initial surcharge factor qi is calculated and then the
feeder vertical load is calculated using qi, see formula shown on form.
Alternatively, two other emperical methods of calculation are
offered - Bruff's method and the method proposed in the Bridgestone
conveyor design manual, see the Calcs, Calculate Pull-out Force from Hopper
Input your feeder and material data and then once you have
obtained the feeder vertical and horizontal pull out loads you can use the method shown
below to model the belt feeder conveyor.
Once you have the magnitude of these Pullout force tensions,
you should design the Feeder as a normal conveyor and add the Pullout Tension as a
Adjustment in the
You will note that two Tensions are given:
Starting or Initial Pull-out force
Running or Flow conditions Pullout force.
The higher Starting force is required to overcome the interlocking (or bridging) of the
material whilst stationary. Once it is flowing, the force required reduces.
- Build a model of the conveyor
- Go to Calcs, Feeder Calculations and enter
the hopper dimensions and material properties
- Press Calculate
- Transfer the Feeder Flowing Horizontal Resistance
Force Ff to the
Conveyor Sections, Tension Adjustment column.
- Re-calculate the Conveyor using ISO, CEMA or VISCO buttons
- The Tension Adjustment will have been added to the conveyor
model - details can be seen in the Tension Calculation Reports.
- Note the conveyor absorbed and installed power and the
Starting Torque Factor which depends on starting method and motor.
Now you should substitute the Running
Pullout Tension with the Starting Pullout Tension in the Tension
adjustment and re-calculate the conveyor. If the absorbed power is less than the Installed
Power x Starting Torque factor then there is sufficient power and torque to start the
conveyor. A numeric example is shown below:
Conveyor Speed = 1.0m/s, belt power = Te x Belt Speed.
Effective Tension (3kN) and Absorbed power without Tension
Adjustment = 3kW say.
Calculate hopper and add a Running Tension adjustment of 2kN
say. Te is now 5kN and absorbed power 5kW. Installed power is selected as 7.5kW motor
started Direct on Line with starting torque factor of 200% FLT.
The Starting Tension adjustment is (say) 4 x Running = 8kN
say. So for starting the Te becomes 3 + 8 = 11kN or 11kW and we have available 7.5kW x
200% = 15kW so it is OK.
After Calculations are done you can view, Print or Export the
The following references are shown if you would like to
research these methods further.
- McClean A.G, Arnold P.C, 'A simplified approach for the
evaluation of feeder loads for mass flow bins', Powder & Bulks Solids Technology Vol.3
- A.W Roberts et.al, 'Wall Pressure-Feeder Load Interactions in
Mass Flow Hopper/Feeder Combinations', Bulk Solids Handling Vol 6 No.4,
- A. E Maton, 'Belt Feeder Design: Starting Load Calculations',
Bulk Solids Handling 8 2009
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