Tension of conveyor belts
Determination and adjustment of the initial tension of PVC, PU, and Silicone conveyor belts with textile ply (plies)
Conveyor belts or conveyor belts are intended for conveying.
During the initial installation, the tension adjustment is essential to ensure optimal operation of your installation.
The conveyor belt is made of textile ply and PVC or PU coating on 1 or 2 sides.
The type of textile (polyester, cotton, ...), the number of plies and the width of the belt have an influence on the initial tension of the laying.
Textile ply belts are usually made of polyester fabric. The number of plies varies from 1, 2 or 3.
The elongation at 1% corresponds to the value in Newton per mm of width to elongate the strip by 1%.
Ex = 8 N/mm To lengthen a belt by 1% we need a load of 8 Newton per mm width.
The more plies we have, the higher the value of the 1% will be.
The value of the initial laying tension is expressed in % and is generally between 0.1 and 0.5 %.
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Determination and adjustment of the initial tension of monolithic conveyor belts without textile fabric
The monolithic belt has no textile ply, only a thickness of polyurethane (PU).
Elastic bands are mainly used on applications with fixed centre distance (no mechanical tensioning system).
Shore A hardness, thickness, and width have an influence on your initial tension.
The monolithic belts are endlessly spliced according to a manufacturing dimension (length L0 at rest).
The length L1 corresponds to the length of the belt with the tension (belt under tension on the conveyor).
To obtain the LO rating, the % of initial band elongation or generally called pre-tension is deducted.
Example for a stretched length of 1000 mm with an initial elongation of 5%, we obtained a manufacturing dimension of 950 mm (1000 - 5%)
Monolithic conveyor belts are generally short, less than 10 metres in length.
The value of the initial laying tension is expressed in % and this value is generally between 0.2% and 5%.
Shore hardness from 65 to 85 shore A
(Max. length = 3000 mm)
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Shore hardness from 86 to 100 shore A
(Max length= 10000 mm)
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The % stresses given are for information only, it is necessary to make an accurate calculation taking into account the shaft load to determine the stress on the axes or bearings.
Methodology for applying the tension value
Make a no-load (tension-free) marker 1000 mm long on the belt.
Apply the tension from 0.1 to 0.5 % depending on the belt.
Moving the tensioning roller to extend the marker
Example: if 0.3 %1000mm + 0.3% = 1003 mm
The initial marker will lengthen to 1003 mm.
(for wide belts it is advisable to measure both sides to avoid too great a difference in tension which would lead to a bad guiding of the belt).
WARNING:
Tension data and values are given for information only. Tanals cannot be held responsible for any misinterpretation or misuse.