Siemens Aktiengesellschaft

Georg Koehler

Ulrich Schaetzle

Bernd Granz

Arnim Rohwedder

Helmut Reichenberger

Dietrich Hassler

Hans Kaarmann

Gert Hetzel

Hubert Schwark

Hermann Kuehnke

Rudolf Harder

Martin Scheidt

A pressure pulse source for generating acoustic pressure pulses in an acoustic propagation medium has a foil arrangement formed by a number of electrically contacted piezoelectric foils stacked directly on top of one another with no interstices between the foils, and employs a drive system for driving the individual foils in succession according to the traveling wave principle.

Pressure pulse source operable according to the traveling wave principle

An apparatus for generating acoustic rarefaction pulses, i.e., a negative pressure pulse, has a pressure pulse source and reflector having a negative reflection factor, and an acoustic propagation medium filling the space between the pressure pulse source and the reflector. The reflector has a boundary surface facing toward the pressure pulse source, consisting of a medium which is acoustically soft in comparison to the acoustic propagation medium. The boundary surface medium is separated from the acoustic propagation medium by a wall which is impenetrable by the acoustic propagation medium.

Apparatus for generating acoustic rarefaction pulses

A pressure pulse source, of the type suitable for generating shockwaves, has a positive lens for focusing the pressure pulses onto a focal zone. The positive lens has an acoustic exit face which has a shape, in a focusing zone, for focusing the pressure pulses and a shape, in at least one measurement zone, which deviates from the shape in the focusing zone. A pressure sensor containing a piezoelectric polymer foil is disposed at the measurement zone. The pressure sensor, or a number of such pressure sensors, generate signals which are used to monitor the pressure pulses emerging from the positive lens, such as by acquiring their peak value.

Pressure pulse source having a positive lens with a pressure sensor

A shockwave generator for extracorporeal lithotripsy has a housing filled with an acoustic propagation medium, through which shockwaves propagate, and in which an ultrasound applicator is disposed for locating a calculus to be treated. The ultrasound applicator has components which may be damaged if traversed by shockwaves. At least a portion of the ultrasound applicator in which these components are disposed is therefore acoustically shielded with a substance having an acoustic impedance substantially differing from the acoustic impedance of the propagation medium, so that essential parts of the shockwaves are reflected thereby and thus the non-reflected parts do not reach the shielded portion of the ultrasound applicator with sufficient energy to damage the compartments.

Shockwave generator having an ultrasound applicator shielded from

An ultrasonic sensor which is particularly suited to measuring the sound-pressure amplitude in the focus range of a lithotripter and includes in a region a piezoelectrically activated polymeric foil, which is coupled to electrodes. The polymeric foil is mounted in a housing, which has a convex curved, dome-shaped surface at least in one region located opposite one of the flat sides of the polymeric foil. A simple measurement of the sonic field is thus made possible directly on the rubber-diaphragm encased, water-filled delay path of the lithotripter.

Ultrasonic sensor

A shock wave generator for use in an apparatus for non-contacting disintegration of calculi in the body of a life form (extracorporeal lithotripter) having a coil with helical windings and a membrane of electrically conductive material disposed opposite the coil, the membrane terminating a space filled with a liquid. The coil is connectable to a high voltage supply. The coil has two layers connected in series and overlapping each other in parallel planes, with the respective current direction and winding direction of the layers being selected in combination to intensify the magnetic fields of each layer. A layer of the coil having a smaller voltage difference relative to the membrane is disposed immediately adjacent the membrane. The arrangement increases the useful life of the membrane without significantly reducing the efficiency of converting the electrical energy into shock wave energy.

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Geisfeld, Germany

Georg Koehler