Conveyor Belt Tension

A Simple, Solid Approach

Ensuring proper belt tension is a vital issue in conveyor operation – one that affects belt tracking, overall belt performance, and the life of the belt itself. All conveyors use some form of take-up device to adjust belt tension to the optimal level – one that not only prevents slippage between the belt and the drive pulley, but also guards against possible material spillage caused by too much belt sag between idlers.

Take-ups also compensate for belt shrinkage or stretch, and allow for extra belt length storage for making belt replacement splices. While take-ups can be either manual (mechanical-style) or automatic gravity, manual take-ups are found in a majority of conveyor units, particularly those that are less than 80-feet (24m) in length.

 

MANUAL MECHANICAL STYLE TAKE-UP
MANUAL MECHANICAL STYLE TAKE-UP

Considerations of Manual Take-Ups

Although manual take-ups are practical and cost-effective in shorter, lighter conveyors, they present challenges. There are many different types and styles of manual take-ups, and many different means used to tighten them. But what they all have in common is this: Even if you know how much tension you need (measured by PIW or pounds per inch of width), with a mechanical-style take-up, it’s difficult to determine just how to get there.

For example, with an automatic counterweighted take-up, you throw so much weight on it and you’re right on tension requirements. But how do you judge if belt tension is too tight or too lax when using a manual take-up? For most operators it’s often a matter of time-consuming trial and error.

Use this simple rule of thumb:

  • Belt sag between return idlers (mounted at 10-foot (3m) intervals) should be between 1-3 inches or 25-75 mm no matter the belt size.
AUTOMATIC GRAVITY STYLE TAKE-UP (1)
AUTOMATIC GRAVITY STYLE TAKE-UP

Try this simple step-by-step process to ensure that you are within the above requirements:

    1. Take a piece of tape and cut it to 6-inches (152mm)

   2. Mark the center at zero

   3. Indicate one, two and three-inch (25, 50, 75mm) marks to the right and left of zero

   4. Center the tape on your return idler roll

Now, it is easy to measure the belt sag and adjust the tension.

Remember:

Proper belt tension is critical to efficient conveyor operation. Consult with your equipment dealer or manufacturer to choose the most effective, easy-to-operate take-up systems.

Certainly with the stretching and wearing process involved in installing a new belt, tensioning can become an everyday task, so specifying the right take-up system is important. But after initial stretching, belt retensioning becomes just another facet of your scheduled routine maintenance program. The simple tips we’ve shared can make the chore quick and easy.

001: Conveyor Belt Tension

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