Наука и техника (Nov 2020)
Plastic Deformation and Electrophysicochemical Treatment of Tubular Medical Concentrator Waveguides
Abstract
Ultrasonic methods for eliminating vascular obstruction are widespread throughout the world. The advantages of such methods are the absence of surgical intervention, a low probability of complications, and a low cost of treatment. Ultrasonic waveguide systems for the destruction of intravascular formations and elimination of vessel obstruction are made in the form of hollow or continuous long rods of constant and variable cross-section (concentrator waveguides). The development of new methods of treatment based on the use of stepped ultrasonic waveguide systems of a tubular type is underway, allowing to supply fluids to the zone of dislocation of an intravascular formation. The presence of a hollow spherical tip with axial and lateral micro-holes in the distal part of such waveguide systems, designed to influence the resulting cavitation jet, both on the intravascular mass and on the affected area of the vascular wall, allows the vessel to be restored with a simultaneous increase in the elasticity of the vascular wall. Such a combined vibration and shock and cavitation effect is currently one of the most effective methods of treating intravascular formations. An analysis of the sizes, structures and materials for the manufacture of tubular concentrator waveguides shows that their shaping can be carried out by various methods: cold deformation, mechanical, hydroabrasive treatment, using welding (or related processes), electrolytic, and also combined processing methods. The existing processes for obtaining long products of small diameter, based on plastic methods, mechanical processing and physical and technical methods, have a number of disadvantages that do not allow the manufacture of tubular concentrator waveguides with the required characteristics. The paper presents the results of the analysis of literary sources, as well as the results of experimental studies, which have made it possible to substantiate the choice of methods for the step-by-step manufacture of tubular concentrator waveguides: obtaining a tubular stepped element by unrestricted drawing, obtaining a working tip by distributing and crimping, obtaining side holes in the working tip by electrochemical сutting.
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