Vandezande - Hydropower Screw Pumps
Screw pums are mainly used to pump large amounts of liquids to a relatively limited higher level. Screw pumps are mainly used for controlling water levels in canals and rivers but they are also used for transferring contaminated water in water treatment installations (return activated sludge pump, influent pump).
Products Details
Hydropower screws produce electric energy by passing large amounts of liquid via a turbine from a higher to a lower level. The electro-mechanical configuration is similar to that of a screw pump.
vandezande supplies screw pumps and hydropower screws of a very high quality and offers the possibility to combine both techniques in one and the same screw pump unit. The conflicting boundary conditions for optimal liquid levels are regulated by a hydraulic powered valve at the upper level which determines the amount of flow by the action of the turbine (as function of the revolutions per minute – r.p.m.) and, at the lower level the screw pump body has adapted blades.
The main advantages of screw pumps and hydropower screws are:
- High flow
- High efficiency
- High reliability
- Low maintenance
- Long life (little wear and tear)
- Fish friendly and easily installed in natural streams (due to the atmospheric function principal and the relatively low nominal revolutions per minute)
- Self drawing
- Easy access
- Possibility to run dry over longer periods
At vandezande a screw pump consists of the following main components:
Screw pump unit
The screw pump unit consists of a central tube, on which blades are welded to form a continuous spiral thread. Depending on the required flow a two or multiple bladed spiral is fitted.
Screw pump trough
As well as a custom made concrete trough, for the installed screw pump, it is also possible to choose either a steel trough, mounted together with the screw pump in a rectangular concrete trough, or a self-supporting prefabricated steel unit which is provided with the necessary supports. With this last option, the screw pump together with the trough and drive line are delivered as one unit.
Splash guards
The purpose of these guards is to minimize the leakage rate which in turn optimizes the take-up rate of the screw pump thereby increasing the efficiency.
Upper bearings
The greased upper bearings take up axial as well as radial forces. The bearing housing is either wall or floor mounted. Self-aligning bearings are used to take up any misallignment, originating from distortion due to a sagging of the screw pump.
Lower bearings
The self adjusting lower bearings only take up radial forces and allow for thermal expansion of the screw pump. The lower bearings are mounted in a cast-iron housing with an alloy specially designed for this application. Different types of lower bearings are available: grease lubricated, oil lubricated or without lubrication (ecological bearings).
Drive unit
The drive unit consists of an external brake fitted on the rotating shaft of the motor connected to the rotating shaft of a right-angled or parallel gearbox via a transmission belt or flexible coupling. The low speed shaft of the gearbox is connected to the screw pump shaft with a flexible coupling. Screw pumps are fitted with a backstop brake in the gearbox. Hydropower screws are fitted with an external brake fitted on the rotating shaft of the gearbox.