CIRCULAR SCRAPERS
Sludge scrapers for circular tanks utilize either central drive or peripheral drive. This depends on the process, tank diameter, design and sludge loads. Circular scrapers can be studied through various classifications. They can be classified as central driven fixed bridge scrapers and peripheral driven rotating bridge scrapers with regard to their drive. The length of a rotating bridge scraper can be equal to the basin diameter or a fraction of the basin diameter. The solid load of the treatment plant determines the method of sludge disposal. The sludge that accumulates at the bottom can either be scraped into the sludge funnel or be pumped to the pipeline of the central structure by suction pipes. Numerous options can be proposed for both methods.
- CENTRAL DRIVEN FIXED BRIDGE CIRCULAR SCRAPERS
Central driven scrapers are manufactured as column or fixed bridge mounted. Concrete or steel fixed bridges are commonly used. Central driven motor, shaft and pallets are used. Scraper is mounted to the bottom bearing. Sludge is collected in the sludge cone by the help of the pallets. Shaft is fixed at the bottom conical shaped construction with bearing. Scraper pallets are connected to the pallet arm. Easily changeable scraper rubbers are used on the pallets. Bridge mounted: The bridge-mounted configuration has a bridge spanning the full diameter of the tank, at the centre of which is mounted a drive. The output of the drive is a shaft, which is connected to the main rake drive shaft or torque tube. Column mounted: The column mounted centre drive requires the construction of a column or post in the centre of the clarifier tank. A drive is positioned on this post. The drive has an output drum on the outside on to which is suspended a rake cage. The rake cage rotates and supports the rake arms.
Removal of the settled sludge can be provided by the following ways:
- Scraper blades
- Sludge pumps
- Suction
Sismat Uluslararası also provides central driven fixed bridge circular clariflocculators commonly used in water and wastewater treatment plants. Clariflocculator is a combination of flocculation and clarification in one unit which is especially designed to treat the screened and degritted industrial wastewater and to promote coagulation, flocculation and sedimentation processes using different zones of the clarifier unit for having an optimum performance. It has two tanks where the inner tank is operated as a flocculation unit and the outer tank is operated as a clarification unit. In this type of clariflocculator, the drive unit is fixed at the centre of the bridge and the tubular centre shaft is connected to the drive unit. There are two structural rake arms mounted on the shaft which are provided with blades to rake the sludge accumulated at the tank bottom.
FEATURES AND BENEFITS OF SISMAT ULUSLARARASI CENTRAL DRIVEN FIXED BRIDGE CIRCULAR SCRAPERS
- Long lifetime
- High degree of reliability
- Effective scraping
- Easy-to mount and –transport
- Can withstand very high sludge loads
- Scraper bridge rigid and resistant-to-torsion
- Fast and precise installation
- Low operational and maintenance cost
APPLICATIONS
- Municipal wastewater treatment plants
- Circular primary and secondary sedimentation tanks
- Industrial wastewater treatment plants
- Circular primary and secondary sedimentation tanks
- PERIPHERAL DRIVEN ROTATING BRIDGE CIRCULAR SCRAPER
Sismat Uluslararası Peripheral Driven Rotating Bridge Circular Scrapers mainly consist of a central pivot structure with power distribution system installed at sedimentation tank’s centre part and a travelling bridge.
Removal of the settled sludge can be provided by the following ways:
- Scraper blades
- Sludge pumps
- Suction
For the system designed with scraper blades, peripheral driven rotating scrapers removes the settled sludge by scraper blades in the central located sludge collection pit. Mounted to the central concrete structure, the bridge is fabricated in standard profile construction in order to resist static and dynamic loads. Sludge is scraped to the sludge cone by rotational movement with a peripheral speed changing from 2 to 4 cm/sec. Polyamide wheels, rubber scrapers under the sludge scraper and swing joint of the arms ensure the smooth rotational movement of bridge.
FEATURES AND BENEFITS OF SISMAT ULUSLARARASI PERIPHERAL DRIVEN ROTATING BRIDGE CIRCULAR SCRAPERS
- Long lasting and reliable design
- High scraping efficiency
- Simple and reduced maintenance
- Easy handling and fast assembly
- Can handle high amount of sludge
- Easy application also on existing units
- Low operational and maintenance cost
APPLICATIONS
- Municipal wastewater treatment plants
- Circular primary and secondary sedimentation tanks
- Industrial wastewater treatment plants
- Circular primary and secondary sedimentation tanks
