In the pharmaceutical industry, pill coating is one of the final steps before the product is packaged and shipped. Not all pills are coated, but any pills that could have an irritant effect on the stomach are usually coated with a substance that will dissolve only in the small intestine. Sometimes pills are coated to make swallowing easier or just for branding purposes.
No matter the reason for pill coating, consistent pressure and/or flow control is required to complete the task. Flow can be used very effectively in spraying applications to overcome any build-up in the nozzle to maintain consistency.
However, in this application, a QB3 is being used to control the pressure of N2 to the coating fluid. A speed sensor is measuring the speed of the conveyor and providing this information to the controller. The controller then calculates a command signal to the QB3 based on the speed of the conveyor. This allows the spray to remain consistent no matter what speed the pills moving.