Weekly Intake: A Water Intake Systems Blog

Traveling Water Screen Chain Tensioning

By Ken DeCoursey

 

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Chains are the heart of a water intake system. They keep everything up and running, the same way our hearts keep our bodies up and running. And problems with the heart can cause a whole host of issues. In the case of water intake systems and traveling water screens those issues include worn parts and system downtime. Read on to find out more about chain tensioning, and how to fix some common issues.

 

Chain Tension is Crucial

A loose chain can impact your entire system. As the chain joint components like pins, bushings and rollers wear, the chain “stretches”.  A loose chain can cause the basket and chain assembly to drag through and rub the curved boot plate makes up the entire bottom of the screen. After a period of time, this type of wear and tear can cut grooves in the boot plate (see image below). If the grooves get deep enough they could sever the plate from the sides of the traveling water screen.

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On the flip side of the coin, an over-tensioned chain can also cause issues. In this case, the chain will wear the top of the head shaft take-up bearings until the bushing is worn into the cast bearing housing. This will cause damage to the end of the headshaft itself, and it might have to be replaced.

Chain tension and head shaft leveling go hand-in-hand. If the headshaft is not level because of improper chain tensioning, the headshaft can begin to walk to one side of the screen or the other. This can cause issues such as :

  • The chain rollers not riding in the center of the head sprocket tooth inserts
  • The head shaft bearing bushing wearing unevenly
  • Wear on the outside or inside of the chain, etc.

 

How to Fix Improper Chain Tension

Keep in mind that regularly scheduled maintenance checks can help prevent some of the issues mentioned above. But in the event that you do encounter an issue with your chains, more often than not it is something that you can fix yourself.

For example, if the head shaft becomes unlevel because of chain tension. To level the shaft, we typically recommend that the screen be locked out and tagged out so it will not come on when the screen is being worked on.

The rear splash housing should be removed, and several baskets should be removed to gain access to the shaft. Adjustments should be made by tightening the side capstan nuts on the top of the screen. This will tension the chain at the same time. A general rule of thumb is to tension the capstans until they are tight, then back off a turn and a half.

Care should be taken to not tension one side of the chain all the way before moving to the other side. Alternate from left to right while tensioning as you would when tightening lug nuts on an automobile. If these steps are completed properly, the chain will be restored to the proper tension and the head shaft will be level.


Ensuring that chains have the proper tension is one of the maintenance areas covered by our new 3-year maintenance contracts. Visit our Traveling Water Screen Services page to learn more about these plans and our other service options.

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