Control System Upgrade Case Study


Granta were approached by a large injection molding company in the Midlands who manufacture a range of dosing valves for a well-known UK cleaning chemical manufacturer.  This particular range of dosing valves include a venturi and the chemical manufacturer uses them to mix the cleaning chemicals into water to ensure correct dilution rates.

The parts for these dosing valves are molded and assembled and the completed assemblies then require 100% testing. The injection molding company have three test units for this purpose which are quite elderly, and whilst they generally operate satisfactorily, there are no electrical, pneumatic or hydraulic (water) circuit diagrams available and the personnel who built these units are no longer available.  This made fault finding and troubleshooting very difficult. The units also did not meet current safety requirements and therefore needed upgrading.



Granta were initially commissioned to examine all three units and produce a report on their condition with recommendations for update and improvement. The report found that whilst overall design and functionality was good and the data acquisition system which had been recently upgraded also worked well, the electrical control system was in poor condition, was very untidy and did not meet current safety standards. Granta recommended utilising all the existing pumps, valves, sensors and data acquisition system but stripping out and rebuilding the controls system to modern standards. An option was also proposed to incorporate an uninterruptible power supply for the computers running the system.

After considerations of the report, Granta were invited to quote for the upgrade work and were subsequently awarded the job to complete this upgrade. The test rigs were transported to Granta’s Whittlesford workshop for the rebuild and testing, one at a time, to leave two rigs in service at any one point.

Control System Case Study