Insulating plate for ultrasound absorption in liq(s). - contains reverberatory non-porous particles in vulcanised rubber matrix and presents no perpendicular surfaces to the sound

摘要

Insulating plate (I) for low-reflection ultrasonic absorption in liqs., esp. water and aq. solns., consists of a polymer matrix (II) contg. embedded substances (III); (I) is mounted on a reverberant base and has, on the other side facing the incident sound, a geometry which presents practically no surfaces perpendicular to the direction of this sound, esp. a pattern of wedges, pyramids or cones; the novelty is that (a) (II) is a vulcanised rubber mixt., (b) (III) are reverberant and of greater density than (II) and (c) (III) are non-porous and are not bonded into the matrix. (III) are glass, pref. solid, with a non-angular shape; rubber component of (II) is at least 60% (pref. 100%) EPDM, or contains polyisobutylene copolymers and/or polypropylene oxides; total wt. of (III) is 20-40% of the wt. of (II); density of (III) is 2-3 times that of (II); the prod. (speed of sound in II) x (density of II) does not differ by more than 10% from the prod. (speed of sound in the sound carrier (water) x (density of carrier); density of (II) does not differ by more than 6% from density of sound carrier; (III) are approx. spherical, with at least 93 wt.% of the particles of max. length not more than 20-60 microns; (III) do not project out of the matrix on the side facing the sound. USE/ADVANTAGE - (I) is useful for the calibration of ultrasonic equipment for medical diagnosis or therapy, (targets for this must have not above 1% reflection in the range 0.8-15 MHz), and for the linings of measuring tanks for similar applications, which also require good physical, chemical and biological stability.