Abstract: Infinitely adjustable calibrating shell includes a central piece formed by strips or bands which are hingedly connected to each other and intersect like an extendable lattice that is formed into a shell. Preferably, the ends of the strips are movably connected to annular heads. The inner diameter of the central piece which is decisive for the calibrating process, can be modified by axially changing the distance between the annular heads, the cross section of the central piece having a circular shape in each axial position. The infinitely adjustable calibrating shell is suitable for continuous extruded plastic parts, in particular plastic pipes.

Abstract: Infinitely adjustable calibrating shell includes a central piece formed by strips or bands which are hingedly connected to each other and intersect like an extendable lattice that is formed into a shell. Preferably, the ends of the strips are movably connected to annular heads. The inner diameter of the central piece which is decisive for the calibrating process, can be modified by axially changing the distance between the annular heads, the cross section of the central piece having a circular shape in each axial position. The infinitely adjustable calibrating shell is suitable for continuous extruded plastic parts, in particular plastic pipes.

Abstract: The invention relates to a device for detecting faults in and/or measuring the wall thickness of continuously moving strips, sections or tubes of plastics, using ultrasonic signals. To this end a number of ultrasonic heads (A, B, C, D) with transmitters and receivers are disposed distributed over the width of the strip or section or the periphery of the tube. The signal, emitted by a transmitter of an ultrasonic measuring head (3) and reflected without scatter, is received by the receiver of said ultrasonic measuring head (3), while the scattered signals reflected on the tube, section or the like are received by the receivers of its adjacent ultrasonic measuring heads (A, B). The inclusion of the scattered and reflected signals in the measurement appreciably increases the measured area per measurement in comparison with using exclusively the signal directly reflected without scatter.

Abstract: The invention relates to an ultrasonic measuring apparatus for determining the geometrical position of a boundary between two materials in a first material from a reference place, more particularly for wall thickness or fault testing. To enable even very thin-walled materials to be measured, the measuring apparatus isolates the reflected ultrasonic signals from the ultrasonic mixed signal received by the receiver, which consists of the ultrasonic signal reflected at the boundary to the first material and the ultrasonic signal reflected at the boundary to the second material, so that the time of impingement of the reflected signal is clearly determined for the determination of propagation time.