Seriously new thinking...
Progressive Cavity Pumps
Netzsch progressive cavity pumps are high efficiency, positive displacement pumps which handle water or farm dairy effluent. They have efficiencies around 85% compared to the standard irrigation pump's 60% efficiency and the effluent solids pump's 40% efficiency. This means that you can generally use a motor of about 7.5 kW to perform the same duty that would otherwise need a 15kW centrifugal pump.
Furthermore, these pumps have a constant flow output. Thus the pump will supply the irrigator with the same flow rate, irrespective of hydrant distance or elevation, so that irrigator performance will be similar at any hydrant on your property. In many ways they are also like a flow meter, where the running time is a direct measure of the amount of liquid being pumped. (Variable speed drives will alter this fact, if one is fitted)
In the past, progressive cavity pumps have had a reduced life when pumping the sand and grit contained in effluent produced directly at a dairy yard so low efficiency, but effective solids-handling centrifugal pumps took over this duty. But things are changing. Now that effluent is dispersed by travelling irrigators with nozzles down to 11 mm diameter, it has become very important to ensure that solids larger than this are kept out of the liquid or else blocked nozzles will be the result. Sand traps and storage ponds now make greatly improved grit traps so the nature of effluent has changed dramatically. With the grit removed and the bulky solids particles screened out, the time of the progressive cavity pump has duly arrived with all it benefits -
- constant flow (in spite of line pressure losses and hydrants at different heights);
- the ability to handle 10 mm solids
- and about 1/2 of the power consumption compared to the inefficient centrifugal solids pumps.
A further benefit is that the pumps have a self-priming ability providing the running parts are kept wet during priming. Thus you no longer need a floating pump on a pond - the pump can be parked on the bank or out the side of the embankment about 2 metres above the bottom of the pond. It is desirable to have dry-running and over-pressure protection, all the same, in the event that the irrigator shuts off the flow or blocks, or the pond empties.
Progressive cavity pumps are not new. They were invented in France in 1939 and have since been used to pump sausage mix, tomatoes and fruit, oils, sewage sludge and a host of other liquids and semi-liquids. The fact that they are still in demand for these duties is a simple testimony to their valued performance.
We have chosen to supply the Netzsch (German) version of this pump because of the Netzsch Group's proven track record in this area of expertise. Visit www.netzsch-pumps.com and see for yourself. Sustainable farming means we should strive to reduce energy use and here is a pump that fits sweetly in to this ideal.