HeadsUp Newsletter - Vol 4:03: March 2007

Although Trendy, Should Perforated Plate Screens be YOUR Choice of Equipment?

Headworks^® Inc. has been manufacturing the Perforator screen for 10 years. Our first unit was installed at a food processing plant in Austria in 1997. Since then, additional units have been installed in the United States, including plants in Texas, Arkansas and Florida, all working to the customers’ satisfaction. During the 10 years that Headworks^® has been manufacturing this product we have learned a great deal. The Perforator is a quality product in cases when fine screening is needed; however the technology can sometimes be misapplied.

The Perforator Screen is available with 3 mm to 6 mm openings. Larger openings tend to allow fibers to blind the media. A long fiber will only partially make its way through the screen opening. As the screen belt lifts the fiber hangs on both sides of the screen where it can weave with other fibers and blind the screen. Once the fibers are woven it is next to impossible to clean the screen. Some plants have been known to take a torch to the perforated plate screens to clean them.

Perforator Screen Fourche Creek Plant, Little Rock AK Wastewater Utility

Perforator Screens handle typical sanitary flows but are not recommended for combined sewer applications unless they are protected with a course screen from large debris typically found in combined sewer applications. Whether a step shape or rounded screen element with intermittent lifting ledges are used, the carrying capacity of the screen is limited. Objects larger than 3-4” will remain in the channel and require manual removal or an upstream coarse screen.

High solids concentrations are also a concern due to the lifting capacity and speed of the screen belt.

Little Rock Wastewater Utility handles only sanitary flow at their Fourche Creek Plant, but upon installing our Perforator unit, we learned of the large number of long and large fibers that were present. The faceted shaped screen elements are kept clean by the rotating brush. The plant is pleased with the mechanical performance of the screen. Dwayne Lackey, Maintenance Superintendent, states "we feel the Headworks Perforator Screen is mechanically sound, operates well and in accordance with the design specification."

Mahr Bar Screen Fourche Creek Plant, Little Rock AK Wastewater Utility

Dwayne also has the unique situation of having a Headworks Inc. Mahr Bar screen running in a channel next to the Perforator screen, giving him a true side-by-side comparison of the two technologies. Dwayne goes on to say that he believes the bar screen to be more suitable equipment for his plant and cites its simplicity.

This is a perfect example of how important it is for our customers to examine all of the variables affecting the content of their flow and take the time to discuss with our team of expert application engineers which Headworks equipment will give them the best results for their wastewater screening needs. One of the many advantages of choosing to purchase Headworks Inc. products is that they are custom built to suit each application … according to the specifications! Click here to contact our engineers to develop the right specifications for your system.