In filling applications, encoders are often used for table positioning. Feedback from the encoder helps ensure that the item to be filled is in the correct position before the filling mechanism activates.
For example, bottles, tubes, cans, or cartons are transported to a filler via a conveyor, rotary table, etc. The encoder is mounted to a motor, drive shaft, or another suitable axis. When the proper number of counts is reached, the controller sends a command to activate the fill system. In many designs, the fill process is completed while the containers are still moving.
Augers, rotary fluid dispensers, and peristaltic pumps use encoder feedback. Often other sensors such as vision, proximity, or laser, are also used to detect container orientation and container location. Encoders can also provide feedback on the motion of a fill nozzle or dispenser that gets lowered to, and withdrawn from, the container. Some filling mechanisms travel in sync with containers, and this motion also usually requires encoder feedback.
Mechanically, shaft, thru-bore or measuring wheel encoders will work, depending on what design is most readily integrated into the system.
Electrically, variables such as resolution, output type, channels, voltage, etc., can all be specified to meet the individual application requirements. While incremental encoders with quadrature output are frequently used, absolute encoders are gaining favor with some machine designers.
Environmental considerations are important when specifying your encoder. Take into account the encoder's exposure to liquids, fine particulates, extreme temperatures, and washdown requirements. An IP66 or IP67 seal protects against moisture ingress, while a stainless steel or polymer composite housing to mitigate the effects of harsh cleaning chemicals and solvents.
Examples of Motion Feedback in Filling
- Food and beverage bottling
- Personal care products tube filling
- Household chemical powder dispensing
