Method and arrangement for determining the wall thickness of cylindrical hollow bodies

摘要

The invention relates to a method and an arrangement for determining the wall thickness of cylindrical hollow bodies, especially for checking the dimension and for determining the corrosive erosion of the inner surface of pipelines, for example of pipes carrying fresh steam over a long period in power stations, using suitable elastic waves. This is achieved in that, according to the invention, elastic waves which revolve in a circular manner and are in a frequency range having a wavelength corresponding to the order of magnitude of the external radius of the hollow body are excited in the cylindrical hollow body, and the maximum gains of the excited waves and the associated frequencies and ordinal numbers of the resonance are determined, from which the radius ratio alpha = (Ri)/R of the hollow body is determined, and the wall thickness d = (1- alpha )(D)/2 is calculated, with the aid of the calculated dispersion relationships (in this case: R1 = internal radius, R = external radius, D = diameter). For implementation, according to the invention, an assembly which consists of a transmitter and receiver is arranged in the measurement range of interest in the hollow body, the transmitter being connected to a tunable generator and to a frequency meter, and the receiver to a visual display unit.