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ENTA - Circular Bridge Scraper
ENTA design, manufacture and install a range of scraper bridges for all types of circular settlement tanks with diameters up to 60 meters. In all cases the structures are designed by ENTA’s engineers to withstand all of the loads and stresses placed upon the bridges and manufactured to the highest of engineering standards. All superstructures and underwater assemblies are protected to customers’ specification.
The most common form of circular tank scraper is the rotary half bridge This is mounted on a central slewing bearing supported on a tripod assembly and is driven by an end carriage travelling around the periphery of the tank.
In addition to the standard half bridge scraper, ENTA manufacture twin and triple arm rotary machines.
Small bridges are manufactured using a beam structure whereas larger bridges require a lattice or girder structure which gives the required strength without excessive weight. All bridges are manufactured in either steel, which can be finished to customers’ specification, or aluminum.
The end carriage unit incorporates a small electric motor and gearbox which drive onto the peripheral wall via a cast iron wheel fitted with a polyurethane tyre. The unit is designed to give a peripheral speed of between 1.0 and 2.0 meters per minute depending on machine design.
Scraper blades are designed in a helical curve formation which maximizes scraping efficiency and thus sludge removal. Scraper blades are hinged 400mm above the floor of the tank, an arrangement which provides for a more positive scraping action.
Scum removal can be effected by using a number of different scum removal systems, ENTA can supply a ramp type, and rotating box type .
Channel Cleaning
- All rotating bridges can be fitted with any of the following types of channel cleaning systems:
- Rotary Brushes
- Pressure Washers
- Chains
- Fixed Brushes
Hydraulic lift Scrapers
This is a design of rotating half bridge scraper specifically designed for use in flat bottomed final settlement tanks. The scraper blades, consisting of linked individual Vee formations, have a tube leading from the apex of the Vee up to the trough, suspended from the bridge so that its base is below top water level. Because this creates a head differential, the sludge collected in the Vees by the rotation of the bridge is simultaneously conveyed up into the trough. As this is a continuous action, there is no sludge build up in the bottom of the tank. The rate of discharge can be varied from each discharge tube by having adjustable bellmouths fitted to the top of each top. Sludge is removed from the trough by a siphon discharging into a collection system within the central assembly.