The Spaans screw generator combines high efficiency with extreme reliability, fish friendliness and smooth running making the screw generator a durable solution for the future.
Spaans Babcock have a long proven track record in the supply of high quality Archimedean screws, drives and ancillary equipment.
The screw generator works in the opposite direction to an Archimedian screw pump. The screw pump pumps the water up, the generator screw rotates due to the flow and head of the water. The rotativing motion is transferred to the driver unit. The rotating motion is transformed by a generator into electricity.
Screw generators are a relatively low cost option for generating renewable energy from water flow that has a relatively low head. They are ideally suited for run of river flows from leats or river weirs.
Each screw generator is purpose built to suit the flow and head of the specific site. Typically heads vary from 1-5m (from 1.8-2.5m for river weirs) and flow from a few hundred litres per second to around 11,000 litres per second.
Screw generators can be supplied in sizes up to 4.9m in diameter. Spaans Babcock can give support throughout the design of the hydropower plant including the installation of the screw, drive unit, generator, control panel, coarse screen, gates, and electrical grid connection.
Upon receipt of a completed screw generator enquiry form and flow data Spaans can provide a recommendation for the equipment. On the enquiry form are the options for supply of standard equipment. In general for river weirs the best solution is usually a fully integrated compact unit.
• Screw in Concrete Trough
This is a screw that is to be installed into a pre-formed concrete structure that would be designed and constructed by others. It would require considerable installation time of a specialised nature including construction of drive plinths, upper and lower bearing plinths and screeding of the trough. The installation process can be from 2 to 5 weeks depending upon the size of the screw. Initial civil costs are higher but the equipment cost is lower. Crane lift weights are lower, however more items need to be lifted. This design can be used for difficult to access locations.
• Screw with Trough Liner
This is a steel liner that comes with the screw generator. It is coated on the upper side in the same manner as the screw and supplied ready to be grouted in by the civil team. This type of liner reduces the amount of civil works required for the trough. However, bearing foundations and plinths are still required and installation can still take from 2 to 5 weeks.
• Compact Screw (fully integrated)
This is a totally self contained unit requiring minimal civil works. It consists of a steel trough which is fully fabricated including upper and lower bearing foundations and drive foundations. It usually comes supplied as one piece from the inlet to the outlet and has been pre-aligned at the works before shipping. Minimal civil structures are required to support these units at the top, with a simple anchor point being required at the bottom. It is usually delivered and installed within 1 day using a crane.