Keeping the cleaners clean
15 Jan 2000
The production of surgical disinfectants, a process that involves many stages and technologies, presents a perfect example of the resources required for building a continuous processing system.
The production plant is automated, and each of the eight finished products are fed into the packing line via 300-litre buffer tanks. Operation is via a Mitsubishi PLC, desk top computer, FixDmacs Scada and modem.
The raw materials are delivered as 5 powders and 24 liquids. Each of the powders is accurately blended with selected liquids using five Tomal batch make-up powder metering systems. To ensure the clean and safe handling of the powders during unloading at the make-up station, the weigh hoppers are filled via vacuum hoses.
The liquids - which vary in consistency from water to waxes - include extremely hazardous substances such as ethanol. A simple drum-emptying stable using pneumatically operated pumps transfers each liquid to small holding vessels.
The complete processing system consists of 21 Bran + Luebbe metering pumps mounted on four pump trains. Three of the pump trains are synchronised via pulse encoders and variable speed drive control systems.
To enable complete validation of the various products, each pump line contains flow rate verification. In-line mixing of the smaller product group uses a multi-element static mixer. The larger product group requires a more complex procedure and involves the use of a Pentax dynamic shear in-line mixer with variable speed drive.
