Center bolt type acoustic transducer

Claim 1

An ultrasonic transducer comprising two piezo-electric ceramic discs with a high potential electrode therebetween arranged to form a stack, said ceramic discs having flat surfaces, electrically grounded front and rear acoustic resonators axially aligned with said stack and having conforming shapes and at least equal areas cooperating with the flat disc surfaces, axially disposed bolt means for retaining as an assembly said resonators and said stack under predetermined compression, said front resonator having its rear-end portion shaped so that sections transverse to the resonator axis are circular, and the front end thereof being adapted to feed ultrasonic energy for work, said rearend portion having an integral outwardly extending uniformly thick support flange having a thickness along the front resonator length which is small in terms of operating wave length but thick enough to be strong, said transducer having a nodal plane at the flange; mating rigid rings disposed at opposite sides of said flange, a readily compressible heat resistant gasket ring at each side of said support flange, each said gasket ring contacting substantially all of the opposed surfaces of said flange sides and portions of said rigid rings and also contacting outer surfaces of the transducer''s said assembly parts adjacent the flange, means for supporting said rigid rings in predetermined spaced relationship, said rigid rings forming part of a mount for the entire transducer assembly, said rigid rings having sufficient clearance with respect to the body of said transducer''s said assembly parts to accommodate limited vibration isolation at said gasket rings consistent with mounting rigidity between the transducer assembly and said rigid rings, the generally distributed compression of gasket rings between gasket compressing surfaces preventing the formation of destructive localized hot spots in said gasket material; said transducer having minimum interfaces to minimize interface losses and the flange transmitting directly to said front resonator load pressure without significantly affecting the nature or distribution of the predetermined compression force on the ceramics and without increasing the bolt tension significantly.