Mass flowmeters help reduce product wastage

Krohne's Optimass Coriolis mass flowmeters are used by BASF to help reduce product wastage and potential downtime during the manufacture of industrial paints and varnishes.

BASF Coatings is using Krohne's Optimass Coriolis mass flowmeters to help reduce product wastage and potential downtime during the manufacture of industrial paints and varnishes at its plant in Munster, Germany.

The instrument is used in the milling process, where colour pigments are ground before being added to paints and varnishes.

These pigments are passed through the mill several times to ensure that particles are broken down.

This process can take up to 48 hours and is often carried out at night and weekends.

Previously BASF used a mobile paddle mixer which was connected to the mill via a hose.

This was manually passed from the output to the input of the mill to rotate the process.

BASF found this very labour intensive and it required constant supervision because of the potential risk of spillage and leakage when disconnecting and reconnecting the hose.

BASF was keen to automate the process and develop a solution that would eliminate the need for supervision and also safeguard against leakage to reduce waste and downtime.

Krohne's recommendation was to integrate its Optimass flowmeter between the output and input feeds to the mill.

This measures the flow rate of the pigment and is configured to trigger an alarm and shut down the process if a sudden change is detected.

BASF use a variety of different pigments in its manufacturing processes, most of which have a viscosity in excess of 7,000 Pas.

They are pumped at low pressure, approximately 5,000 kg per hour, around the milling circuit.

Measuring their flow rate precisely is made difficult because their characteristics change with flow and also because of their high pigment content.

Krohne's Optimass proved an ideal solution.

Its single, straight-tube design is able to accurately measure high viscosity material at low flow rates.

It also does not introduce any additional pressure drop into the system, which meant that BASF did not have to increase the performance of its pumps.

The Optimass provides a signal output to a PLC, which every 90 seconds compares it with previous measurements taken.

If there is a difference of more than 360 kg per hour an alarm is generated.

During tests the lowest detectable leak was found to be 36 kg per hour, however the alarm had to be set higher than this to take into account fluctuations in flow rate.

Work is currently underway to find a way in which BASF can take advantage of this lower level.

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