Chain Scraper System

Our systems are trusted and used by municipal and industrial customers worldwide from small private companies to leading international contractors. 

• We have nearly 40 years of experience in this field as the company was founded in 1986
• We have delivered close to 4000 chain scraper systems
• Deliveries in all five continents and almost 90 countries

Highly flexible solution for a wide range of applications

We offer all possible configurations for rectangular basins from top and bottom scraping to multi-layer systems and all the needed accessories for these systems including scum pipes, beach plates and system controls.

• Composite (GRP) scraper flights are extremely durable and lightweight
• Available in various models for different applications. 
• Sludge does not accumulate inside the c-channel flight and maintenance is easy even after years and decades of use. 
• High-grade wear shoes and rubber materials are selected according to the type of application. 
• Additional features such as brushes can be installed on the scraper flights as needed.
• Installation of the flight is very easy and there are no limitations for the placement of the flights. 

2. Collector Chain

• LK-160 is available with three strengths (ST, MD, HD), selected according to the clarifier type and size. 
• DEWA chain design has distinctive advantages, as the spacer sleeve rotates over the sprockets (same principle as in bicycle chain). This design feature maximizes the life span of the collector chain and the sprockets as the wear is minimal. 
• All pins carry the load of the chain when in contact with the sprocket and there is no risk of overjumping (no need for an overjumping protection device).

3. Shaft assembly

• All shafts (head shafts, tensioning, idler stubs), collars, and wall brackets are made of high-grade steel materials (AISI304, AISI316, Super Duplex)
• Designed for heavy sludge loads. 
• Shaft sprockets can be turned around, which doubles the life span of the sprockets. 
• All bearings are lubrication-free and won’t require regular maintenance.

4. Drive assembly

• The Dewa chain scraper system is run by an electric motor and gear that are selected according to the application and required speed with extremely low energy consumption (typical drives vary from 0,12 kW to 0,37 kW). 
• Sprockets and drive chains are selected according to the application.
•  The drive unit is protected with an easily removable cover. 
• The running of the system is monitored by electrical torque-sensing against under or overload.

5. Carry, return and bottom rails

• All carry and return rails including wall brackets are made of superior stainless steel materials. 
• This allows smooth sliding and low friction with DEWA wear shoe parts and a practically infinite lifetime.

6. Tensioning Shaft Assembly and Collector Chain Tensioning Device

• A unique collector chain tensioning system allows chain tensioning without draining the tank and adjusting can be done while the system is running. 
• This feature saves time and resources and is the most operator-friendly solution. 
• The system prevents misalignment faults which are caused by loose chains. 
• The system can be equipped with an automatic tensioner and sensor indicators that are especially convenient when the sludge collector is totally under the water and is not visible to the operator

7. Parallel Run Control System

• A safety system that monitors the alignment of the scraper flights. 
• The system will stop the chain scraper system if the scraper flights are not aligned correctly to avoid any possible damage or additional damage to the system.

8. Floating Scum Removal Pipe

• For floating surface scum removal, we offer an effective “scum pipe”. 
• Can be equipped with a manual or electrical turning actuator
• Size (typically from DN250 to DN400), rotating degree and technology can be selected according to the water level variation. 
• We also deliver additional weirs and channels as needed.