, an Italian developer of ceramics production equipment, has used Emerson Process Management’s Micro Motion Coriolis technology to help with the design of a skid-mounted blending system for ceramic slip and colouring materials.
The new skid systems enable batches of the ceramic raw materials to be blended at the time of use, compared to the traditional approach of mixing and maintaining mass quantities for use over extended periods.
Conventional production of coloured ceramics involved preparation and blending of the base suspension or slip, and the colour, in quantities of tens of tons at a time. Repeated colour analysis and colour addition ensured that once the colour had reached the desired level, enough material was available for a reasonable production quantity to be modelled and fired, achieving a consistent result.
Typically the blending occurred in ball mills, and then in underground agitation tanks, which required significant amounts of energy to maintain the agitation, over the days while the material was being used in the modelling process. Inevitably the large tanks and mills required a lot of cleaning, thereby wasting the material that was deposited on the tank walls and associated pipework. High quality products required dedicated tanks to avoid impurity carry-over from previous batches.
Euroelettra Sistemi realized that the most efficient mixing process would be a skid-based unit, and that this would require accurate monitoring and control of the separate materials being delivered. The barrier to achieving this was overcome once Euroelettra investigated the capabilities of the Micro Motion T-Series flowmeter from Emerson, which provides both mass flow and density measurements. This introduced the possibility of blending the colour and the slip in exact mass proportions, achieving consistent colour hue even though the actual blended volume is small.
The diagnostics available within the Multi-Variable Digital (MVD) core processor of the flowmeter, accessible via a Modbus connection, enables the blending system to identify any build-up of material within the straight measuring tube of the Micro Motion Coriolis flowmeter. The ability to signal when cleaning is required has increased equipment availability by around 50%, and improves efficiency. Cleaning is relatively straightforward, when needed, because of the straight tube design of the flowmeter. The resulting homogeneity of the material supplied has led to a reduction of typical production rejects by over 90% compared to previous skid blending system trials.
Future benefits will follow. Traceability of the process parameters used to achieve each blend enables further production batches to be scheduled as needed, with good colour consistency between batches — which both improves productivity and increases customer satisfaction.