NOVEL PIEZOELECTRIC SENSOR CABLE.

In the two decades that have elapsed since the discovery of the piezoelectric effect in certain polymers, a number of developments have taken place which have resulted in commercial realization of a highly active alternative to conventional piezoelectric materials such as quartz and lead zirconate titanate ceramics. The most exploited material thus far has been the polymer poly(vinylidene fluoride), and there are now a number of manufacturers of thin film piezoelectric PVdF. Vibetek 20 piezoelectric cable is made by a novel process developed by Raychem, essentially carried out in two stages both of which are continuous processes. The first stage is the coextrusion of PVdF with a suitable low melting point alloy conductor, to form a coaxial wire. The second stage processes are indicated schematically.