Sensor Based on the Resonance Frequency for Detecting Overfilling in a Pressing Apparatus

Abstract

When processing in the manufacture for production of paperboard boxes, there arises amount of waste paper as material, which is subsequently sent for recycling. The paper passes through the first crushing device, which ensures small pieces so that they can be transported by pipeline to a pressing apparatus. Paper material in the molding machine is forced into the pits of suitable size due to the additional handling and transport. So both pipe as well as the molding machine may be so congested with material during the failure that the equipment requires unexpected additional cleaning. The sensor detects the level of waste material in pressing device, thereby avoiding congestion in a timely manner and prevents subsequent failure. The sensor uses the resonant frequency of the oscillating rod. The microprocessor controls and evaluates the response of the rod oscillations. Sensor performance was exposed to qualification tests when it shows ability to operate also in extreme conditions such as dirty and dusty surrounding with high humidity and temperature level. Sensor detects the vibration attenuation at the poles of the rod that is caused by touching different materials. Thus may indicate changing concentration level of a material and not just pieces of paper but for example, also sand or other suitable materials or height of fluid surface.