Chemical batch weighing and blending
Automating a chemical weighing and blending process, giving a safe and robust system was the aim. The client did not want to be reliant on a fully automated process where one PLC logic step brought a £200,000 per day production line to a standstill. The company was growing exponentially from a traditional manually operated chemical processing plant with operatives manually opening valves using weight indicators under bulk storage tanks. This ceased to be option for our customer as its order books were full and demand outstripped their ability to supply their great range of insulated building products. The complex blend of chemicals needed precise measurements. The company that went on to win the Queen’s award for industry needed the ability to review stock to ensure continuity of supply. The range of products needing a variety of chemical blends needed to be automatically measure to a high degree of accuracy. The blended recipe needed to have actual batched amounts recorded and moved to storage tanks. With the operators able to record the types of mix and label it when it reached its destination.
The company went on to be the global leaders in the manufacture of insulated roof, wall and panels for the construction industry. Their products are seen as the facades of commercial and industrial buildings, leisure facilities schools and hospitals worldwide. They are unseen in homes as they are built across the world insulating to the highest standards to meet the needs of our increasingly environmentally conscious planet.
Synectic’s instrumentation networked together with an industrial PC gave the best of both worlds, accuracy of high end A to D converters giving the tightest controls over the measurement of expensive an volatile ingredient blends with a computerised system that accurately measures and blends the complex recipes of chemicals which makes up the foam filling in for this Blue chip company’s award winning products giving full graphical representations of the tank farm and user friendly PC software that enables recipe uploading and editing, data downloading.
The weighing and flow measurement is controlled by the SY017 Batch controller which accurately measures and controls complex recipes of chemicals. The system has serial connection to a printer which enables end of batch printouts as well as logging facility where data is downloaded in spreadsheet format for Quality assurance and stock control.
The first site began operating with the Synectic system in 1996 and a similar but improved system was installed in other sites belonging to the group the following year. What the customer liked about the system was;
1. Robustness of the system. Non-volatile storage of calibration details.
2. The system is not reliant on PLCs unlike offerings of most other process control systems they were offered. 1 step in the PLC process failing bringing the entire process to a halt was not an option.
3. Instruments are controlled by a PC which stores all of the recipes and logs the history of all batches that it blends. On screen graphics show representations of tank contents indicate pumps and valve status and enable measuring mixing blending and movement between one storage vessel and another
4. If the PC develops a problem the controllers could be used as standalone instruments to accurately measure by weight and by flow all of the ingredients. Reverting to a semi automatic system gave the opportunity to overide controls with accurately measured ingredients and the work flow could be maintained.