With its new level meter Leveltronic, Petersen Service offers the solution to precisely control overfilling or underfilling in the vacuum chamber. To date the level in the vacuum chamber could not be accurately controlled. Thus it was impossible to provide the extruder auger with the constant rates of filling.
Normally the limit switches used are only part of the solution, they prevent a maximum overfilling of the vacuum chamber by switching-off the upstream pre-press or double shaft mixer. However, a control cannot be established since only the upper limit is recorded. An underfilling of the extruder auger is not recorded.
The really reliable solution is Leveltronic the level meter by Petersen Service that can be applied under vacuum atmosphere. This technology enables a measurement of the filling level in the vacuum chamber accurate to centimeters and sends an analog 4–20 mA signal. With this signal, incorporated into a control circuit as a regulating variable, the flow rate of the pre-press or double shaft mixer can be controlled and adapted to the discharge behavior of the extruder auger. This way a constant level in the vacuum chamber is achieved and the operational behavior of the extruder balanced, which is noticeable by constant extrusion velocity and even pressure ratios.