Sludge and scum collectors (Chain & Flight type)
There has been tremendous progress in the Sludge Collector market and the popularity of the rectangular clarifier is rapidly increasing around the globe. The Rectangular Clarifier provides a friendly layout option with minimum dead space between the units as these units can be placed on a common wall. In addition, they can be built one on top of the other (in 2 – 3 layers).
Circular tanks require careful design of the inlet stilling well (inlet buffer) to achieve a stable radial flow pattern without causing excessive turbulence in the vicinity of the central sludge hopper.
DEWA L-K 160 collector chain links are not integrally molded like other collector chain links available on the market. DEWA L-K 160 is a combination of side links, pin, spacer sleeve and locking ring.
They are made of reinforced thermo plastic materials that resist elongation, wear and corrosion as well as provide full dead load bearing capacity throughout the full length of the link. This advanced engineering has distinct advantages, as the spacer sleeve revolves and gives way when it rotates over the sprockets so the wearing will not appear in one position as they appears on integrally molded links. Due to this design feature the life span of the DEWA L-K 160 is considerably longer than most other solutions.
DEWA C-channel heavy duty scraper flights are pultruded with an polyester resin and reinforced transversely and laterally with glass roving and fiberglass mat. Scraper flights are equipped with UHMW PE wear shoes (carry, return and guiding) and stiffeners.
The stiffeners are made of reinforced fiberglass material, as scraper flight. This is to provide extra rigidity to the scraper flight and to protect against bending and torsion. A sufficient number of rubber lips for the leading edge as well as end of the flights will be supplied according to size and nature of application. C-channels are available in three different sizes with max length of 12m. Flight attachment links are available in both non-metallic and SS materials according to customer requirements.
All shafts (head shaft, idler and stub), collar and wall brackets are made of SS materials and are solid in construction and available in various sizes according to project requirements. Unlike fibreglass telescopic shafts, DEWA shafts are designed to withstand heavy sludge loadings (e.g. intermediate settling), so the system can be installed in extra large clarifiers.
Shaft sprockets (head shaft and idler), are made of UHMW PE materials which have a superior water and abrasion resistance. All shaft sprockets are reversible and this effectively doubles their lifespan. All sleeve bearings are of the non lubricable type and thus no regular maintenances is required.
Contrary to other systems available in the market, DEWA provides a sophisticated mechanism for collector chain tensioning. DEWA is the first supplier who introduced this operator friendly configuration to the market. Because of its unique design feature, the collector chain can be tighten without draining and it is possible to observe the parallel movement of the tensioning.
All carry and return rails and wall brackets are made of stainless steel. This is to allow the smooth sliding of flights over the rails, as the coefficient friction of SS on PE in virtually non-existent.
Depending upon the demands of application, drive units manufactured by world-class suppliers are available in a variety of sizes and with many different features. To safeguard system function and reliability, an electronic shear (over and under load protection) will be provided.
This device constantly observes the variation of current and will be activated immediately when it exceeds the preset value. On request, a flight monitoring system will be provided to detect the parallel movement of the system which will comprise of proximity switches, a coupling mechanism and PLC. Drive chain, drive and driven sprockets are available as well.
The Scum Canoe is design to remove floating matter from the clarifier in conjunction with the sludge collectors. All parts are made of SS materials and are available as manual or with an electrical actuator. Wall brackets and sleeves are made of high grade lubrication-free plastic materials and other non-metallic materials.
The removal efficiency of the chain and flight type collector mechanism is much higher than that of bridge type mechanisms. This is due to the large number of flights. Moreover, the power consumption and maintenance cost of these devices are minimal. These mechanisms can be assembled with non-metallic components including Collector Chains, Head and Idler Shaft Sprockets and Scrappers, which not only ensure easier erection due to their light weight but also contribute to making the product have a longer life. These Scrappers are driven through the collector chains on both ends of the tank and in-turn are carried on the sprocket mounted on the solid stainless steel shafts running across the tank width, which are supported on the tank walls.
Thanks to our professional partners who appreciate quality, reliable products, today there are over a 1000 DEWA sludge and scum removal systems in operation throughout the world.