Rockwood Electronic Materials produces special chemicals for the
semiconductor manufacturing sector. A recent project at the company's
Riddings, Derbyshire plant involved the development of an automated
mixtures production plant, which was commissioned a couple of months ago.
Features include an algorithm-controlled batch processing scheme based on
the Wonderware In-Batch SCADA system. The variable fill rate elements of
In-Batch operate via a series of Burkert process valves that are equipped
with Profibus DP fieldbus interfaces. Under operator control, the system
uses recipe algorithms to bring measured quantities of chemicals, via the
Burkert valves, through various process stages.
On validating an operator batch command, the In-Batch system
automatically opens the delivery valve from the first raw material tank
indicated for the recipe and starts the transfer pump. It continuously
monitors the weight of the raw material tank's contents, shutting the
valve and stopping the pump when the required amount has been delivered
to the mixing vessel. These operations are repeated for all the other
batch ingredients.
Integrity of cleanliness in the handling of sometimes aggressive
chemicals was a criterion in the selection of these control valves,
explains Rockwood facilities manager, Andrew Hutchison. We chose Burkert
process valves because of their robust construction in appropriate
materials and their integral Profibus DP control heads, which were easy
to integrate into our control system.