May 1, 2014
Proper synthetic media maintenance and efficiency demands a much different mindset than that required for traditional wire cloth, punch plates, or other metal media. Consider that for many plant managers, the old adage of “that’s the way we’ve always done it” is often top of mind.
Because the world of wire cloth is as familiar as an old shoe, the distinct maintenance and operating parameters of long-wearing synthetic urethane and rubber media remain a focus of continuing education in the marketplace.
“Maintenance mindsets are slow to change — even though synthetic media arrived on the scene decades ago,” says Pete Babinski, a regional manager for Polydeck Screen Corp.
Babinski says he is one of a number of veteran regional managers who team up with the company’s applications engineers and media manufacturing personnel to provide operations with optimum synthetic screen media solutions and effective maintenance programs.
Think quality control
When working with wire cloth, workers typically detect excess wear when a hole is ultimately blown through the cloth, allowing oversize material to fall through and contaminate product stockpiles. Consequently, the common mindset is to assume that the same wear pattern and result will happen with synthetic media — but not so.
“Operators tend to look for a hole to weld or repair rather than looking at the actual gradations,” Babinski says. “Frequent quality control sampling to detect sudden or gradual spec changes is the most effective method to monitor the wear life and condition of synthetic screen panels.”
Polydeck’s Ontario Regional Manager Alex Caruana agrees.
“With modular synthetic panels, the maintenance crew can catch any wear issues before they become a contamination problem. For example, the quality control team can identify if production is slightly off on its #1 sieve, perhaps — allowing the crew to start gauging its screens and checking for any wear,” he explains. “After this routine maintenance, they simply take a few minutes to change out a panel or two, and they are up and running again.”
Ditch the downtime
Another education issue for synthetic screen media concerns understanding the frequency of changeouts. While an operator may be accustomed to replacing wire cloth on a weekly basis, synthetic media may last an entire season or more, according to David Ciszczon, Polydeck’s eastern aggregate industry manager.
Due to the modularity of synthetic panels, he stresses that operations typically have to replace only one or two panels, versus changing out an entire wire cloth section.
“One person can safely and easily carry up to four 1-foot x 2-foot panels up to the screens during any changeout. Plus, when changing out wire cloth mats after just a week or less, quite a bit of material is being wasted,” he says. “Ultimately, synthetic media significantly reduces downtime and maintenance costs, providing a quick return on investment.”
Visualize for daily reliability
Conversely, as operators recognize the longer wear life of synthetic media, they should not fall prey to the common set-it-and-forget-it mentality.
“It’s very important to inspect your synthetic screen decks periodically for loose panels or unusual wear patterns which may be caused by a change in feed or by high-pressure spray water, for example,” says Shane Gee, Polydeck manager for the south-central region. “Consider that if a panel is not replaced before it is worn entirely through, this could result in damage to the steel supporting deck or to the fastening system.”
To increase uptime performance and eliminate costly maintenance downtime due to blinding and pegging, synthetic media may be the right solution.
“Modular synthetic rubber panels that are made of a low-durometer rubber compound provide superior flexibility, making them an ideal solution, particularly in applications that deal with the effects of moisture on small particles and fines,” says Joe Teague, western aggregate industry manager for Polydeck.
He cites the challenges of a Kansas-based operation, which had experienced considerable blinding over of the small openings on the wire cloth bottom decks of its dry processing screens. Not only did this result in considerable maintenance downtime, but it also cost the operation a percentage of saleable product loss.
After flexible synthetic rubber screen panels were installed to replace the wire cloth, blinding was eliminated, and the operation was also able to make a higher quality aglime product.
“Bottom line: performance is most important. When you can run all week without blinding regardless of the rain or moisture content, it doesn’t take long to get the payback from a new deck,” Teague says.
Debunk the major open area myth
As to maximizing open area, Polydeck upper midwest regional manager Dick Stiles explains that the percentages of open area listed in conventional wire cloth media catalogs are based on “all the openings” in a section of the screen, but a good portion of those openings may be blocked by bucker bars, crown rubber, clamp rails, and center hold-downs, causing actual open area to be compromised by as much as 40 percent.
“A Wisconsin-based specialty sand plant wanted to increase throughput and efficiency on its scalping circuit without having to purchase a larger screening unit,” he says. “With the use of smaller vibrating screens, particularly in underground operations such as this one, we have to utilize all the open area we can find.”
To address the operation’s needs, they configured a screen deck with panels featuring more holes per square foot, as well as a frame system with more narrow attachment rails than those typically found on conventional frame systems.
In the case of synthetic media, the open area is sometimes calculated by ignoring the border. “The traditional synthetic screen panel has a large border or dead area around the perimeter that often is not taken into account, and thus the open area percentage is overstated,” says Tommy Daniel, Polydeck regional manager for the southeast. “To avoid the specification of undersized or oversized vibrating screens, open area needs to be calculated by taking the total number of openings in the screen panel and determining the percentage of actual open holes versus the complete surface of the panel itself. A simpler approach is to compare the open area between two different panel brands by merely counting the number of holes on each screen panel.”
Avoid the last-minute mentality
Be proactive with media maintenance. While the use of synthetic screen media reduces maintenance labor, it does not eliminate it. Maintain the reliability of equipment by repairing or replacing worn components before they actually fail.
It is also important to be proactive on inventory management to avoid downtime and to streamline the maintenance process. Polydeck West Coast Regional Manager Alan Tindall points to the practice of specifying certain screen panels that can be used in multiple applications. “Operations may be able to get a useful life out of a panel in one location, then move it to another application where it will function for a period of time as well,” he says, adding that crews should work with their suppliers to seek interchangeability of installation systems and side wear plates, as well, so that they can reduce costs by having to stock fewer replacement components.
“If your media supplier has provided you with a diagram of the deck layout, post it as a reference tool for the maintenance crew. This is especially important if the deck layout comprises a number of different panel types and opening sizes,” Babinski adds. “This will ensure that the correct layout is maintained as panels are replaced — and will ensure that the deck design remains accurate for the given application. Also, at winter shut down, your media supplier should conduct a complete screening circuit survey and give you a list of recommended repairs, replacements, and parts for each deck.”
Maintaining the right mindset in synthetic media maintenance and efficiency requires working smarter, not harder. Above all, rely on the mindset of getting it right — from the start. With proper information and specification from the beginning, maintenance ease and operational efficiency are sure to follow.
This article was provided courtesy of Polydeck Screen Corp.