Leaf Tobacco Processing Automation
Tobacco preparation area automation
The first step to process tobacco leaves is its preparation. At the preparation area, the product is unpacked and dropped on conveyors where the operators manually remove undesired materials. To assure the flow constancy of the product, which is essential for the whole processing, it is necessary the addition of dynamic weighbelts. These weighbelts issue the feedback reference for the inverters that control the speed of the preparation area conveyor thus keeping the flow of tobacco.
Tobacco conditioning automation
The conditioning step is necessary for the perfect threshing and separation of lamina and stem. The conditioning happens inside the conditioning cylinder. Temperature and humidity are controlled inside the cylinder to create an environment where the leaves open themselves. The precise control of the conditioning parameters results in less production losses and dust generation. Automation at this part of the process means the control of the fan speed and the opening of water and team valves.
Threshing line automation
This segment of the production line is responsible for the separation of lamina and stem. A good measure of efficiency is the size of the output particles. The bigger the particles, the best is the processing quality. Quality at this part of the processing is quite dependent on the operators skill and experience. Automation helps to achieve better performance by allowing precise control of motors speeds, flaps opening and adjustment of threshers and separators. Operation data can be recorded in data banks formatted as recipes. This recipes are used to reproduce operation adjustments when processing similar classes of tobacco.
Lamina dryer automation
After the separation, the lamina must be dried and conditioned. This is accomplished in the lamina dryer. The automation system controls drying and cooling temperature inside the drying compartments as well as the moisture applied to the product along the conditioning compartment. The equipment is set to operate at a steady state prior to the product arrival. Proper adjustments are commanded after the product is first detected at the dryer entrance. Feed back controls are applied when the flow of product becomes stable. In the event of a line stop, a correspondent sequence of control is applied to the equipment. A moisture measuring system installed at the dryer exit and temperature sensors along the equipment feed the plc with the measurements necessary for the dryer control. The presses blockage determine the dryer stop.
Processed tobacco press automation
After processed, the tobacco is packed in bales or cartons. This is made by pressing the product into the packing enclosures in presses composed of two ore three pressing units. The average net weight is about 200 kg for each box. The automation system controls the precise weight measuring, the pressing sequence, the filling distributors, the boxes positioning and conveyors command. The presses units operate in turns. While one unit is pressing the product in a box, the other unit is filling another box.
The system allows the operator to stop the automation sequence and manually command the equipment whenever required. In case the pressing operation is stopped, a command is issued to stop the dryer.
Conveyors sequencing automation
Conveyor and turntables transport the boxes from the pressing area to the stores. Optical sensors detect the presence of the boxes and command the conveyors to run whenever there is a box to be transported. Motors are turned off when the conveyors are empty for energy saving. Longer conveyors can be used as temporary storage.