First, the Effective Belt Tension (TE) must be calculated. TE is the sum of the tension required to move the empty belt (TC), the tension required to move the load horizontally (TL), and the tension required to lift the load (TH).
Example 1. TE = TC + TL + TH
TC = F_{1} x L x CW |
F_{1} = .035" [Normal friction factor for average conditions (over 20°F) to move empty belt.] L = Belt length (ft.) CW = Weight of conveyor belt components. (Table A of the Engineering Manual) |
TL = F_{2} x L x MW |
F_{2} = .04" [Normal friction factor to move load horizontally.] L = Belt length (ft.) MW = Material weight (lbs. per lineal foot). MW = 33.3 TPH or Total material load in lbs. |
TH = H x MW |
H = Difference in elevation of terminal pulleys (ft.) MW = Material weight (lbs. per lineal foot). MW = 33.3 TPH or Total material load in lbs. |
TE = TC + TL + TH |
See all calculations above. Continue with calculation of TS and then TO |
Calculations
Second, additional tension must be added to the effective Belt Tension (Te) to prevent slippage on the drive pulley. This is called Slack Side Tension (Ts), or commonly called T2.
* Ts = D X Te
* D = Drive factor (Table B in Engineering Handbook: Drive Factor)
Next, the total tension To = Te + Ts
To is the total operating tension, or commonly called Allowable Working Tension, and is expressed in PIW (pounds per inch of width). To is sometimes referred to as TL.
Additional tension must be added to the Effective Belt Tension to prevent belt slippage on the drive pulley. This is called Slack Side Tension (TS).
TS = D x TE (Table B in Engineering Handbook: Drive Factor)
Total tension herein called Operating Tension (TO), sometimes called Allowable Working Tension, is the value used to select the reinforcement ply combinations.
TE + TS
TO = –––––––
WTE = Effective Belt Tension at drive
TS = Slack Side Tension
W = Belt Width (inches)
The next step is to select the proper reinforcement (usually fabric) combinations. A number of alternatives are usually available, and the final selection is narrowed by the following considerations:
The values of the belt carcass to pass the above consideration should be available in the conveyor belt manufacturer reference manuals or printed information for belt selection.
The final selection of the alternate combinations should be made by considering costs and availability from a reliable source.