Robust and efficient mechanical bar screens are critical to protecting valuable downstream infrastructure at your plant, pumping station, or treatment facility from waterborne debris during storm surges or sustained flooding.
Here we look at how to choose bar screens for water treatment that will protect your facility and equipment from everything that nature (and humans) might send your way.
Looking Upstream: Bar Screens Built for the Future
As climate change drives increasingly extreme weather around the globe, severe storms and unseasonal rainfall are making catastrophic flooding events more common.
That means rivers and streams are peaking higher and carrying more water during weather events, but it also means flood water carries more debris, including trees, car tires, discarded coolers, and huge amounts of plastic waste.
That’s bad news if you’re operating a raw water intake system equipped with 20th-Century debris control.
To safeguard your facility from whatever this millennium has to throw at it, you need a bar screen able to handle heavier and bulkier materials and a greater volume of waterborne waste.
Continue reading to learn what bar screen equipment is, how mechanical bar screen equipment works, and the specific designs and technology that are worth investing in today to protect your infrastructure and downstream processes from the next generation of storms.
What is a Mechanical Bar Screen?
Bar screens are sturdy vertical or inclined bars that trap and remove natural debris, trash, and other solids from raw water entering your facility or plant.
Mechanical or traveling bar screens use automated or manually operated cables, rakes, or buckets to remove unwanted debris as it accumulates so flow volumes can be maintained.
Traveling screen systems need to be robust enough to avoid being clogged, jammed, or damaged by large objects or increased debris volumes during flood peaks or extreme weather conditions.
What is the Best Bar Screen Technology?
Different types of bar screens use different mechanisms to remove trapped debris. Each offers different strengths and weaknesses depending on your needs.
Reciprocating Rake Screens
Use a horizontally mounted steel rake system to remove material from screen bars and transport it sideways to a discharge point.
These screens are good for handling variable debris loads and higher flow rates but feature a complex mechanism that requires more maintenance and is unsuitable for many intake configurations.
Catenary Screens
Use a series of cables with rake teeth that scrape debris off the screen bars. These cables move in a loop, removing debris and pushing it towards a collection point.
Catenary bar screens can provide very effective screen cleaning, especially in less robust applications, but cable systems are prone to wear and tend to require more maintenance.
Continuous Belt Screens
Use a rotating belt with perforations to screen incoming water. The belt captures debris on its surface, which is then scraped off and discharged for disposal.
In practice, continuous belt screens are mainly used for capturing smaller particles from pre-screened flows. While able to handle very high capacity flows, their intricate design and high installation cost usually make them unsuitable for front-line debris removal.
Chain-Drive Screens
Chain-drive bar screens use a continuous vertical chain equipped with toothed rake bars to clear debris from the screen surface. The motor-driven chain moves the rake bars up the screen, removing debris and lifting it to a designated collection point.
While not well-suited to capturing fine debris, the versatile design, reliable components, and robust construction of leading brand chain-drive bar screens have made them a natural first choice for a wide range of front-line raw water intake applications.
Chain-drive screens have always offered a great combination of flexibility, affordability, downstream reliability, and value for money for a wide range of water intake challenges.
Today, as flow and debris conditions become more challenging, leading equipment makers are betting on the built-in reliability of this tried-and-true technology to meet the needs of the most demanding raw water intake applications.
Building a Bar Screen for 21st-Century Conditions
Atlas-SSI, a full-service U.S. provider of traveling bar screens, spotted the need for a flexible, reliable chain-drive screen able to handle the more extreme conditions already being encountered by facility operators nationwide.
To fill that gap, the company created the Gator Rake Bar Screen, its toughest mechanical bar screen yet.
“Our field service crews were being asked to repair other rakes on intake structures,” says Rodney Brown.
“Operators felt their options were limited. The existing equipment is just not able to keep up — that’s why they reach out to us. We set out to build the Gator Rake to fill that need with heavier duty components and higher capacity.”
The result was a product that harnesses the simplicity and reliability of the chain drive concept in a bar screen strong and flexible enough to meet any debris-handling challenge, with design features that set it apart from any other product on the market.
Tough
Designed bigger and heavier than other chain drive screens, Gator Rake bar screens and frames are fabricated from stainless steel and carbon steel for unmatched strength and durability.
Strong
- Robust heavy-duty chain designed for maximum strength and durability
- Precision-engineered fabricated sprockets with positive locking mechanism, ensuring consistent and uniform lifting
- Custom-made torque tube head shaft assemblies
- Enhanced performance guaranteed under heavy loads with larger drive motors and reducers
Durable
- Non-metallic teeth to reduce bar wear
- Bolt-on rake arm design for ease of maintenance
- Easily replaceable parts
Flexible
- Adaptable to almost any canal or water inlet
- Gator Rake HD (heavier frame and chains for ultra-robust applications)
Customizable
“These are not off-the-shelf-pieces of equipment,” says Rodney Brown, sales manager for Atlas-SSI.
“We design each one with a specific application in mind. It’s important that we beef it up and size it accordingly but also not oversize it and unnecessarily drive up costs. We design and size each one for the specific application that it’s going into,” he explains.
- Right-sized to your needs to avoid unnecessary cost
- Work with your engineers on newbuilds
- Able to retrofit existing screens
- Includes bar racks
Why Choose Atlas-SSI?
Atlas-SSI offers an unrivaled selection of services to match the strength and quality of our products.
1. Value-Added Integrations
- Integration with conveyors and compactors
- Remote site automation
- Real-time monitoring
2. After-Sales Service
At Atlas-SSI, we stand by our products with ongoing support. As water and debris flows become more unpredictable, regular inspection and maintenance — especially below water level — is critical to ensuring the safety and integrity of your facility.
“Having our commercial hard hat divers available to perform inspection below the water is key because they can check the integrity of the equipment, see if anything is actually lodged in there, and check for corrosion,” explains Brown.
- We come to you – Our certified diving crews and technicians can travel all over the U.S. for service and repairs
3. Parts
Atlas-SSI offers the largest inventory of exact-replacement parts for water screens, regardless of the make or manufacture of your intake screen.
4. American-Built
- Atlas-SSI manufactures all of our screens at our facility in the U.S.
- We don’t sub out work
Atlas-SSI: Upside Solutions, Downstream Benefits
If you’re managing a raw water intake operation in today’s world, you can no longer afford to plan for a best-case scenario. As rainfall, flooding, and debris flows become less predictable, you need to invest now to be prepared for the worst nature can throw at you.
Atlas-SSI’s Gator Rake bar screens combine built-in American-made toughness with flexibility and customizability to match both your intake application and your budget.
You’ll get long-lasting protection for whatever’s coming down the river, backed by Atlas-SSI’s industry-leading full-service support. Now that’s investing for a rainy day.
Contact us today, or click below to learn more.