Using low Voltage DC pumps for environmental research
We all know that electricity and water do not mix well and particular care needs to be taken when using pumps which require mains or generator AC power. Having read HSE guidelines carefully it is evident that 110V is a safer(and therefore recommended) option than using 230V so for some years now Van Walt has only supplied equipment which required a maximum of 110V. In the case of the Grundfos MP1 pump however it must be realised that the voltage is split into 3 phases of 220V so great care must be taken in making sure that the cables are examined regularly to make sure that the cable is in good condition and has that it has not been damaged in any way. One of the main causes of damage is where the cable slides over the well edge. If that is a little sharp then it might cut or abrade the cable. We always therefore recommend that a well guard (looks like a shin pad) is used. Nonetheless, the MP1 remains a very powerful and useful pump for environmental research and has a good safety record.
For many years we’ve been working very closely with our supplier Geotech in Denver in the development and refinement of equipment for environmental research.
Geotech is one of the leading suppliers of this type of equipment in the United States.
From their stable of products, one of their newest additions is a low voltage pump called the Stainless Steel Geosub. It looks very similar to the Grundfos MP1 but has a number of advantages not least that it works with DC voltage downhill from the controller. Let me explain: A 110V supply is fed to the frequency converter by means of a (short) cable from the mains or generator. The controller converts that into low DC voltage which is much safer to work with.
Similarly we’ve started to work with another supplier in Pennsylvania. Fultz Pumps work in a similar way to the Geosub: AC 110V into a controller and from there it is all low DC Voltage.
Both these pumps have other advantages and disadvantages and a choice will be made depending on the requirement. I’ve prepared a table which guides you through the choice process and that is available here: http://www.vanwalt.com/pdf/pump-comparison-table.pdf
Vincent van Walt
Van Walt Ltd
Haslemere March 2010