PVC dryblend

Heater-cooler mixer feeding

The task

Lowest height in existing building
Store PVC from big bags and tank vehicles, convey by means of pneumatic conveying systems and automatically weigh
Dispatch chalk and TiO₂, dose, weigh and feed into the mixing process
Separate weighing of modifier, stabiliser and other additives
Adding and weighing of liquid components into the heater mixer
Manual weighing and addition of micro quantities
Documentation / tracking + tracing / operator guidance
High cycle rate / high accuracy
Conveying, storage, homogenisation and filling of the dryblends
Integration of the heater-cooler mixer in the control and process control system

The Solution

Low construction, separate weighing of TiO₂ and conveying of additives in PVC stream

In addition to conveying the PVC from the silos to the main scale above the heater-cooler mixer, the conveying of pre-weighed additives as well as stabilisers and modifiers in the same PVC stream is one of the special features of the system. The additives are introduced into the process by means of sack discharge stations, the stabilisers and modifiers via combined feed funnels and big bag emptying stations. For this purpose, the dispatched substances are pre-weighed on small scales and introduced into the conveying line. The PVC is then transported into the suction conveyor scale of the heater-cooler mixer.
Because of their special properties, chalk and titanium dioxide (TiO₂) are placed in a separate line and transported to a smaller conveying scale. This also allows the separate addition of the substances into the mixer.
For the addition of micro components, a ManDos station is available for weighing these components. The manually weighed components are fed into the mixer in the further course of the process via a cycle belt.
After conversion, the liquid components are provided in containers. From there they are pumped into small feeding vessels. These feeding vessels are filled, as required, by the heated liquid scale, which empties into the mixer.
After the heating-cooling mixing process, the dryblend is emptied into a mixing tank. In order to achieve higher homogeneity of the various dryblends, they are conveyed into two AZO homogenising silos and mixed again there. After a preset time in the mixing tank and in the homogenising silos, the dryblend is filled into an AZO bulk goods container.
The containers are placed directly on the extrusion lines and feed the extruders there.
The complete system, including the heater-cooler mixer, is controlled, monitored and completely documented by the AZO process control and visualisation system as well as the PLC. The orders are received, processed and documented back to the ERP system via an interface to the ERP system.
Order management in the ERP system takes place in the company centre in Germany and can be remotely controlled from there. The system itself is located in China.