Patent ID: 7250709

Claim:
A piezoelectric actuator for insertion in a flowing media, comprising: a piezo stack having a top active main surface and a bottom active main surface; deformable isolating material in direct contact with at least portions of said piezo stack; actuator housing enclosing said isolating material, said housing having a non-rigid housing shell and a dimensionally stable actuator top arranged on the top active main surface of the piezo stack and dimensionally stable actuator bottom arranged on said bottom active main surface of the piezo stack; electrical connection lines extending from said piezo stack through said actuator housing by means of at least one of said dimensionally stable actuator top and actuator bottom wherein said housing shell is disposed at a distance from piezo stack at all pointer, and a length of the housing shell, when measured along a surface line, corresponds to at least a maximum extend of the piezo stack or the housing shell is able to be stretched to the maximum extent of the piezo stack, wherein the isolating material is one of an electrically insulating fluid and gel, wherein an inside volume of the housing is substantially filled with said isolating material, and wherein the housing shell and the dimensionally stable actuator bottom and the dimensionally stable actuator top are connected to each other in a sealed manner with respect to the isolating material and the flowing media.