The company selected the CFT50 Coriolis flow meter from Invensys Foxboro, which uses digital technology to keep the flowtubes in constant motion so that there is no loss of flow measurement during dynamic flow conditions.
While conventional Coriolis meters were very accurate with steady flow in longer batches, they lacked responsivity to rapid flow changes during the course of short batches. Moreover, when used with viscous fluids such as paint, even small levels of gas in the liquid skewed readings.
"We tried traditional Coriolis meters, but they did not deliver the repeatability we require," said managing director Kevin Beaumont.
Mount Packaging initially tested the CFT50 transmitter on a 40mm flowtube with a nominal flow capacity of 6.8 kg/s. In this application, the CFT50 produces pulses that correlate with product weight, for example three pulses per ml of flowing liquid - and transmits these pulses to a PLC, which counts them and is programmed to actuate the shut-off valve when the target fill weight is achieved.
After a few trial runs, new flow profiles of the batch runs were collected. These demonstrated the new measurement potential that the company was able to achieve with the CFT50.
"We learned to trust the meter, we adjusted our own equipment to improve performance and we are now getting excellent repeatability," said Beaumont.
This consistency has also been proved in full-scale production. One customer achieved repeatability well below 0.1 per cent during 64 consecutive batch runs, at 4.2 seconds to fill 10-litre cans, with a target weight of 14.04kg.
"This technology has huge potential and we're looking forward to taking it out to all our customers. We weren't disappointed,"said Beaumont.
Invensys is a global leader in production technology. The group aims to help customers improve productivity, performance and profitability using innovative services and technologies. Invensys operates in more than 60 countries, with its headquarters in London.