Chain Scraper System

DEWA chain scraper system is a reliable and user-friendly solution for rectangular settling basins. They can be used in various applications, such as water and wastewater treatment, API oil-water separation, stormwater treatment, and desalination.

DEWA chain scrapers can be built one on top of the other in 2 – 3 layers, and are applicable for rectangular basins up to 100m long and 12m wide. DEWA chain scrapers are available in two/three-shaft (bottom or surface) or 4- shaft (bottom and surface) configurations, depending on the clarifier type. 

DEWA chain scraper system includes a unique tensioning system, that allows chain tensioning without draining the tank. This saves time and resources and makes it the most operator-friendly solution. The system is tightened above the water level with a simple screwing system. DEWA tensioning system prevents misalignment faults, which are caused if the chain gets loose. The tensioning system can be equipped with an automatic tensioner and sensor indicators. These features are convenient when the sludge collector is totally under the water and is not visible to the operator.

DEWA chain scraper is designed to operate for decades. DEWA systems are made of high-quality, non-corrosive components. High-grade plastic and stainless steel components make the system robust and reliable. Safety components, such as overload and flight run indicators, enable safe and comfortable use for operators. 

For floating scum collection, DEWA provides a rotating, tubular, skimmer system DEWA Scum pipe. The actuation of the scum pipe can be manual or automatic. DEWA Scum pipes are made of stainless steel.

Thanks to our professional partners who appreciate quality and reliable products, there are over 2 000 DEWA sludge and scum removal systems in operation throughout the world.

Key features

  • Efficient footprint compared to circular basins
  • Low energy consumption
  • Can be built on top of each other
  • High removal efficiency
  • Low wearing rate
  • Low maintenance cost
  • Long life span
  • Light weight
  • Durable and non-corrosive components

CSS Dimension Table

CHAINTypePitchRepture LoadWorking LoadWeight
StandardL-K 160160 mm24 kN13 kN2,0 kg/m
Medium dutyL-K 160MD160 mm35 kN18 kN2,3 kg/m
Heavy dutyL-K 160HD160 mm40 kN21 kN2,4 kg/m
CRAPER FLIGHTSTypeMaterialDimensionsMax Length
C-180C-ChannelGlass fibre80×180 mmUp to 10 m
C-220C-ChannelGlass fibre100×220 mmUp to 12 m
C-330C-ChannelGlass fibre100×330 mmUp to 8 m
Head ShaftUHMWPEZ=8 / Z=12
Idler ShaftsUHMWPEZ=8 / Z=12
Head ShaftAISI 304L/316LHS-150/200
Tension ShaftAISI 304L/316LTS-150/200
Idler ShaftAISI 304L/316LIS-60/70
Head ShaftUHMWPESlide bearing
Idler SprocketUHMWPESlide bearing
Return railAISI 304L/316LZ-profile
Floor railAISI 304L/316LI-profile
TypeHelical Bevel Gear
Drive Sprocket1” Z=21AISI 304/316
Driven Sprocket1” Z=45/60/75AISI 304/316
Drive Chain1” Roller ChainAISI 304/316
HardwareAISI 316