Monitoring of material flow (for different granules in shape, color, grain size, quantities) at the outlet of the dosing unit, by an ultrasonic sensor
The material flow sensor can use ultrasonic waves to monitor in real time whether the screw of the dosing unit is conveying the material to the target area. With this we offer a unique solution in dosing technology for the general plastics processing industry.
Volumetric and gravimetric dosing equipment may encounter conditions that prevent material from being discharged from the dosing unit.
These are for example:
- Bridging of material in the storage hopper
- Motor Shelf not swung in
- No screw installed
- No material filled into the storage hopper.
Even when using gravimetric routines, there is a variable time offset due to causality checks of the measured values in the gravimetric measurement routines. This depends on the setpoint. The smaller the setpoint, the longer the time offset.
It can take up to several minutes before it is determined that no material is being discharged (e.g. due to bridging in the weighing hopper) and a corresponding error is displayed via the control.
This can have serious consequences in the production process.
At a cable manufacturer for automotive cables, the following happened:
During the extrusion process, no main material was dosed for a certain period of time, just a colorant (masterbatch).
Production did not detect the defect via standard quality control because:
The color of the insulation was matching the specifications and also the diameter was correct. In addition, the problem only happened for a short time and the pure colorant insulation was in the center of the spool/reel.
The error was only discovered afterwards by the company who wanted to process the cable and broke the insulation in this process.
The result is a complaint from the customer (in this case to the cable manufacturer).
For instance: the short term non-dosing of catalyst, UV stabilizer or blowing agent could create problems too.
In order to avoid such complications in advance, the material flow sensor is the ideal solution for intensive and extremely fast monitoring of material flow.