Should You Choose a Screen Box Meant for Modular or Tensioned Screen Media?

By Lars Bräunling MAJOR director of product technology

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There have never been more screen media materials and styles for aggregates and mining producers to choose from. From woven wire and steel plates to rubber, polyurethane and hybrid options, it can be difficult to know the correct material for your application. Additionally, although there’s a common perception of modular media as being made of synthetic or polyurethane materials and tensioned as wire, manufacturers offer both styles in many of the same materials. This includes tensioned screen media with the longevity benefits of polyurethane — like FLEX-MAT.

But before you even get to the material type, you may need to choose between modular screen media installed onto a flat screen deck or hooked screen media tensioned against tension rails on a cambered deck.

So, how do you choose? Here are some tips.

Step 1: Evaluate the Up Front Costs and Maintenance

While the sticker price for the initial full deck installation of either type of screen media isn’t the only thing to take into consideration, it can be a factor. Oftentimes the cost for outfitting the entire deck with modular panels is higher per square foot than it would be with tensioned sections. This is because of the number of modular panels required to fill the deck compared to hooked media. Additionally, it can take much longer to install modular panels due to higher screen count. In other cases — such as with classic woven screens — the cost difference between the two styles isn’t significant, so it’s important to consult an OEM or dealer.

Maintenance is where modular truly differentiates. The smaller and lighter panels allow for a faster pinpointing of problems as well as easier, safer and cheaper replacement compared to the cost and effort of replacing an entire tensioned section. This can ultimately lead to lower overall maintenance costs from modular panels compared to hooked. When tensioned screen media breaks, the entire section needs to be replaced.

However, modular screen media only saves money on maintenance if two prerequisites are met. The first is that wear is frequently occurring in areas significantly smaller than a tensioned section would take up. Otherwise, replacement cost and time are going to be a lot higher than on a tensioned deck. This type of uneven and concentrated wear also often indicates setup issues that cause inefficient screening. The second factor is that an operation favors frequent small interruptions for changeouts. The cost of shutting down, losing production and getting the work on the deck done can easily be as expensive as the screen panel itself. In many cases regular scheduled maintenance intervals to change an entire deck, or a larger section like the feed, are the most economical solution. And when an operation compares tensioned and modular screens at the same maintenance interval, tensioned is always more cost efficient.

Step 2: Consider the Screen Media Performance

While modular can shine for its ease-of-maintenance benefits, by nature of being tensioned, hooked screen media is still the leader in terms of screening action. The taut screen sections don’t require the same rigidity as modular screen media and therefore achieve higher levels of vibration for improved material separation. This screen movement not only benefits stratification, it also often prevents blinding and pegging, making it ideal for difficult applications in which material is very wet, contains clay or is very cubic.

This is particularly true for our tensioned FLEX-MAT sections. FLEX-MAT is made up of OPTIMUMWIRE® — the industry’s longest-lasting wire — bonded with distinctive lime-green polyurethane strips. This allows wires to vibrate independently from end to end under material contact. The high frequency of the wires adds to the vibration of the screen box to speed up material separation and passing. The increased screening action also virtually eliminates near-size pegging on the top decks and fine material blinding and clogging on the bottom decks, which increases capacity and reduces maintenance, resulting in a lower cost of production per ton. Plus, the media offers up to five times longer wear life than traditional woven wire and produces a cleaner retained product. MAJOR also offers its own modular version of FLEX-MAT, featuring all of the benefits of the advanced screen media in the convenience of the modular style.

Modular and tensioned media also differ in terms of open area, which can affect the entire screening plant.

Step 3: Evaluate the Impacts on Plant Design

The size and mobility of your operation can have a significant impact on the style of screen box you choose, and ultimately screen media. Tensioned screen media allows for a narrower screen box that can sometimes achieve almost double the amount of open area compared to the same sized plant with modular screen media. This big difference is because modular panels have to sacrifice a part of their surface area to accommodate their attachment adapters and structural material that makes them solid items with some rigidity. By comparison, tensioned panels have blind sections where the support bars hold them up from underneath. As a result, many modular decks need to be wider to reach the same capacity.

On the other end of the spectrum, mines and large stationary quarries that usually have fixed maintenance cycles may prefer modular screen media for its ability to quickly change panels and reduce expensive downtime. Being stationary, these types of operations can get away with larger screen decks to achieve their desired open area while using modular media. However, the principle remains that though smaller modular panels can save money and time when only small sections of the deck wear quickly, they do not automatically provide a better wear life; the right material for the job does.

So what style should you go with?

How to Choose?

The choice between modular and hooked can boil down to size and type of operation, as well as a producer’s priorities. For as much tonnage as possible, tensioned screen media is always the way to go. Modular may be the best choice if the size of your operation allows it and you are looking for the ability to replace smaller screen panels when needed and reduce downtime. For a well set up plant with uniform wear, and where decks are normally replaced entirely, tensioned panels are the cost-efficient solution.

Fortunately, both cambered and flat deck screen boxes can still take advantage of many of the benefits of the opposite style. Flat decks can be outfitted with Crown Curve Adaptors offered by MAJOR to allow the installation of tensioned screen media.

There are a lot of options, but none compare to the screening efficiency of FLEX-MAT, now offered in both tensioned and modular styles.

Call 450 659-7681 or email today to discuss how we can work together to improve your screening and profits.