Screw Conveyor Torque Requirements 1

[drdust]

I want to use a screw conveyor to level loads in bins containing materials such as grain, wood chips, plastic resins. Would like to know how to calculate the required torque.

 

[azertyuiop]

a) first possibility : P = G x L x F1 / 367

G = weight in metric ton per hour
L = screw length in meter
F1 = resistance to flow , usually between 2 and 5 , 2 for light and easy flowing materials and 5 for heavy sticky high friction products
P = required kW for your electro motor

b) second possibility : P = Q x Rho x L x F1 / 367

Q = cubic meters of transported product per hour
Rho = density of transported product in kilogram per cubic decimeter (kg/dm^3)
L = length of screw
F1 = resistance to flow , usually between 2 and 5 , 2 for light and easy flowing materials and 5 for heavy sticky high friction products
P = required kW for your electro motor

C) third possibility : M = P . 9550 / n

M = Torque needed (Newton meter)
P = power (kW) of your motor
n = rpm of the screw axe

You will see that the required kW are usually very low , given the low friction between moved products and wand casing in a horizontal screw. Basically your electromotor has to develop a start torque to get the screw axe wheeling and the product moving , once the thing is wheeling there is no real torque needed anymore to keep it moving.

A empiric method if your screw is already existing , is to attach a light but stiff one meter long rod horizontally to your screw axe , hang weight to the far end of your rod and increase the weight until the screw axe start wheeling. You then have your required torque : x kg-m.