At the Glenfiddich whisky distillery the 'wash' which is created from fermentation of malted barley is distilled in copper pots that are the same size and shape as the original stills set up in 1886 by the company's founder, William Grant.
Heating turns the alcohol to vapour which rises through the neck of the still and is guided down through a water-cooled condenser. At this stage the condensate contains about 21% alcohol, and the distillation process is repeated in smaller 'spirit stills'.
Two pumps are used to push water up to a storage dam for the condensation process. They are run at a fixed speed every minute of the year. Recently, Glenfiddich considered whether the efficiency of the process could be improved without compromising supply.
"In particular, we looked at an ultrasonic level measurement and water distribution system from Siemens Process Instruments," says Glenfiddich's Derek Matheson. The EnviroRanger ERS500 monitors and controls liquid levels providing control outputs to variable speed drives (VSDs) to achieve more efficient pump handling, and eliminates the need for any other discrete control equipment.
Matheson specified two Siemens' Micromaster inverters which have been installed, linked via Profibus to the EnviroRanger, and control signals which are based on the water levels in the storage dam. Now, the pumps no longer have to be driven at a fixed speed and a reduction in speed can provide a saving in energy.
In addition, since the motors are now not met by a huge initial torque that comes with direct on-line starting, maintenance is reduced and life is lengthened.
Contact: Siemens Automation and Drives,
Tel: 0161 446 6645