The Project Manager behind the development of the Industrial Direct Sensors™ from Grundfos was an easy choice. The man behind the first DPI v.1, which has been bought
more than 100.000 times so far was the clear candidate. Kjeld is a Senior Mechanical Engineer in our team and has a great deal of experience in the field.
The requirement list from the sales front were complex and substantial. The geometry requirements (fit to a standard wrench in the possession of any plumber), M12 connector (in the possession of any electrician) and as small as possible to enable any built-in. This meant that traditional steel materials were not an option, and sintering was chosen. A technique which Grundfos masters thru a subsidiary.
From the production, the requirement was that the complete new transmitter platform
should run on the same automated production-line. At the same time, sales wanted it all. 4..20 mA for one-parameter sensing and 0..10V for combi-sensing (incl. temperature readout). And be future-safe with the opportunity to integrate any BUS signal, if a BIG OEM should come along. This meant that the transmitters had to have two connected printed circuit boards.
From product management, cavitation is always a concern – and in heavy duty industrial applications the requirements very tough to meet. We had to push the
sensing element from the flow, and we obtained a solution, where the steel valve used broke, and our transmitters survived the severe tests. The sensor element itself is made out of silicon with our proprietary coating Silicoat®, and as such a steady-state-material. Meaning that the element with returns to its original shape, and hence no moving parts involved and limited drift.
Some customers started to use the VFI in open looped system, which was outside the
intended usage and so we have recently changed the size of the bluff body, so that the border for cavitation is moved up. Flow measurement is still the same, but we have had to change the applicability from 10 Cst to 6 Cst in viscosity. This was done by one of our Technical Key Account Managers on one VFI with success, and this is now implemented across the industrial flowtransmitter range.
All these are small evolutionary improvements to a new transmitter range, which Grundfos is making a new standard within flow, pressure and differential pressure
transmitter in combination with measuring the temperature.