OPTIMASS 7000 ensures new product quality

Lucite International UK Ltd, a global leader in the design and manufacture of acrylic-based products, is using KROHNE?s OPTIMASS 7000 Coriolis Mass flowmeters to ensure its new product is manufactured to strict dimensional tolerances.

Lucite?s Darwen-based plant is a 24 hour operation that manufactures acrylic sheet, used predominantly for manufacturing baths.  During production of its new product a precise amount of acrylic syrup mixture is measured and cast to produce a flat acrylic sheet.

The sheets are manufactured to a strict dimensional tolerance and precise measurement of the mass of acrylic syrup is critical to achieving this.  Overfilling can lead to deformation in the surface quality of the sheet, while under-dosing can result in voids or holes.  Inaccurate measurement of the acrylic syrup results in significant waste and rework.

Lucite needed to measure the flow rate of the acrylic syrup to an accuracy of 0.5 per cent.  This was made particularly difficult because of its high viscosity - approximately 3,000 centipoise.

Initially mechanical flowmeters were used to measure the flow rate of syrup into the casts.  However, the pressure drop across these flowmeters was found to be too high and did not provide the required level of accuracy or stability of calibration ? particularly when used with the viscous syrup.

KROHNE?s OPTIMASS 7000 flowmeter enables Lucite to measure precisely the amount of acrylic syrup mixture that is cast into acrylic sheets, ensuring the new product?s consistent dimensional accuracy.

During manufacture raw liquid methyl methacrylate is fed into a mixing vessel where it is combined with other additives.  It is then passed through the OPTIMASS 7000 flowmeter before being cast.   The OPTIMASS 7000 with its single straight measuring tube features a patented AST design that offers outstanding accuracy and stability when used on low flow rate applications that are common with high viscosity products.

A signal from the OPTIMASS 7000 is fed to a PLC which operates pouring valves that control the flow of the acrylic syrup into the cast.

This is the first time Lucite has used KROHNE flowmeters at the Darwen site.  Rickey Donald, engineering projects manager, at the company said:  ?The mechanical flowmeters we initially intended to use were not accurate enough for us to meet production tolerances.

?I carried out an investigation to evaluate the technical capabilities of flowmeters on the market as well as the costs.  KROHNE?s OPTIMASS 7000 flowmeters met our measurement accuracy needs and this, along with the company?s reputation for quality and reliability, was a key factor in my decision to choose its products.?

KROHNE?s OPTIMASS 7000 Coriolis flowmeter was the first of its kind to incorporate a single straight tube design, which results in minimal pressure drop across the meter.  It has also been designed without flow dividers.  These features allow viscous liquids to be pumped at relatively low pressure without being restricted by the meter.