Abstract: Process and apparatus for separating compressed material containing paper fibers where the apparatus includes at least three hammer rollers arranged essentially in a same plane and each hammer roller includes rotatable hammers. The process includes rotating the rotatable hammers, transporting the material over the at least three hammer rollers in a transport direction essentially parallel to the plane and transverse to the axes of the rollers, breaking up the material into fine material and non-fine material, and separating the fine material from the non-fine material by allowing the fine material to pass through gaps formed between the hammer rollers. The apparatus includes a machine frame and a plurality of rotors arranged next to one another in the machine frame. Axes of the driven rotors are arranged to lie in at least one plane, and the rotors are positioned to form free gaps between the driven rotors.

Abstract: An arrangement for generating natural resonant oscillations of a mechanical oscillating system includes an electromechanical oscillation exciter which on excitation by an electrical excitation signal generates a drive force setting the oscillating system in mechanical oscillations, an oscillation sensor which is formed as displacement sensor and senses the mechanical oscillations of the oscillating system and converts them to an electrical sensor signal, and an excitation circuit which receives the sensor signal and supplies to the oscillation exciter the electrical excitation signal with the frequency of the sensor signal. The excitation circuit includes a phase control circuit which controls the phase position of the excitation signal in dependence upon the phase position of the sensor signal. A phase shift circuit produces a phase displacement of 90.degree.

Abstract: A mass flow meter operating by the Coriolis principle includes a mechanical oscillating system having two straight measuring tubes which are clamped at both ends. In the center of the measuring tubes an oscillation exciter is disposed which sets the two measuring tubes into oppositely phased flexural oscillations. The mechanical oscillations are sensed by oscillation sensors which are arranged at equal distances on both sides of the oscillation exciter. The phase displacement of the sensed oscillations is a measure of the mass flow. The mechanical oscillating system is arranged axially in a support tube. For decoupling the mechanical oscillations from the support tube the mechanical oscillating system is freely suspended in the support tube at each end by an annular diaphragm. The entire mechanical oscillating system including the diaphragms preferably consists of titanium.

Abstract: A mass flow meter operating by the Coriolis principle comprises a mechanical oscillating system having two straight measuring tubes which are clamped at both ends. The mechanical oscillating system is arranged axially in a support tube. In the center of the measuring tubes an oscillation exciter is disposed which sets the two measuring tubes into oppositely phased flexural oscillations. Oscillation sensors sensing the mechanical oscillations at equal distances on both sides of the oscillation exciter generate electrical oscillation sensor signals which are characteristic of the frequency and phase position of the sensed oscillations. An evaluation circuit receives the oscillation sensor signals and generates from their phase difference a measuring signal indicating the measured value of the mass flow. A first temperature sensor is arranged such that it measures the temperature of the support tube and generates a first temperature sensor signal indicating said temperature.

Abstract: An arrangement for generating DC magnetic fields of alternating polarity for the magnetic-inductive flow measurement by means of a field coil which is connected via alternately controlled switching members to a DC voltage source, wherein during the reversal time following the change-over of the switching members a capacitor is connected to the field coil to form a resonant circuit separate from the DC voltage source and the capacitance C of the capacitor in dependence upon the desired reversal time .DELTA.t has substantially the value ##EQU1## wherein L is the inductance and R the ohmic resistance of the field coil.