Long-lasting bearings in solar thermal water pump for developing countries

Profile

Water pump model with large yellow and blue wheels in a greenhouse.

What was needed: Plain bearings for various swivelling and linear movements in the mechanics of a solar thermal water pump
Requirements: Long service life, lubrication and maintenance-free, cost-effective
Area of application: Fluid technology, renewable energies

BSR Solar Technologies GmbH develops solar products for worldwide use. One of them is Sunpulse Water, a motor that uses the energy of solar radiation to drive a highly energy-efficient water pump by means of a thermal power process. The product is to be manufactured and used primarily in developing countries and offers an alternative to conventional diesel pumps powered by fossil fuels. The aim is to make a decentralised, sustainable energy and food supply possible.

Problem

In order to realise various swivel and linear movements in the complex gear unit of the solar water pump, the designers were looking for suitable plain bearings. They needed to be as cost-effective as possible, ideally require no maintenance and have a long service life.

Solution

The solution: dry-running iglidur® plain bearings made of durable high-performance plastic. Bearings of the X series resistant up to +250°C are used for the rod guide (1), iglidur ® G bushings for all-round use in the transverse steering (2) and in the connecting rod bearing (4) with high alternating loads. Slotted M250 double-collar bearings, which are particularly impact-resistant, vibration-damping and wear-resistant, are clipped into the O-shaped connecting rod (3), which is made of laser-cut sheet metal. Also made of M250 material are flanged bushes, which are used in the lower rod guide (5).

Water pump prototype with iglidur G, X and M250 bearings for developing countries.

Transmission unit of the Sunpulse Water water pump

Solar water pump with a large rotor on a wooden pallet.

08 prototype of the Sunpulse Water in field tests in Portugal

Diagram of a water pump with numbered bearing positions for iglidur G, X and M250.

Bearing locations with iglidur plain bearings of the X, G and M250 series: Rod guide at top (1), transverse steering (2), o-shaped connecting rod made of sheet metal (3), connecting rod (4), rod guide at bottom (5)