Treatment of metal strip with ultrasonic energy and apparatus therefor

Apparatus for continuously treating with ultrasonic wave energy metal strip moving through a body of treating solution comprising

• an elongated open top tank having a bottom wall, sidewalls extending along the length of the tank and end walls extending along the width of the tank, the bottom wall of the tank sloping downwardly from each sidewall toward the other sidewall, the upwardly facing surface of the tank bottom wall having the ability to reflect ultrasonic wave energy efficiently,
• means for introducing the moving metal strip into the treating solution near one end wall of the tank, moving the metal strip along a path through the treating solution and withdrawing the metal strip from the treating solution near the other end wall of the tank,
• a plurality of transducer means for generating beams of ultrasonic wave energy, each transducer means having a bottom, the beam of ultrasonic wave energy emanating out of the bottom of the transducer means,
• a plurality of receptacle means, each receptacle means having liquid impermeable bottom and sidewalls for holding a body of liquid other than the treating solution having an upper surface, the bottom wall of the receptacle means being formed of ultrasonic wave energy transmissible material,
• means above the open top tank for supporting the receptacle means with the bottom wall of the receptacle means in contact with the body of treating solution and above the path of the moving strip, and
• means associated with each receptacle means for supporting a transducer means in the receptacle means immersed under the upper surface of the body of liquid in the receptacle means with the beam of ultrasonic wave energy directed downwardly toward the bottom wall of the tank, through the ultrasonic wave energy transmissible material of the receptacle means bottom wall, through the path of the moving metal strip and onto the bottom wall of the tank,
• the plurality of receptacle means being longitudinally arranged along the length dimension of the tank with each receptacle means disposed over the path of one of the marginal portions of the moving strip so as to pass the associated beam of ultrasonic wave energy through the path of said marginal portion of the moving strip,
• the angle of incidence of each of the beams of ultrasonic wave energy impinging on the bottom wall of the tank being such that the reflected beam of the ultrasonic wave energy passes through the path of the moving metal strip at a place located inwardly of said marginal portion of the moving strip relative to the width of the strip.