US Patent 7673515 Vibration sensor

A method for measuring a vibration from four or more equidistant points in a chamber, comprising centering a chamber surface around a center point, containing a fluid within the chamber surface, measuring a fluid vibration from at least four measuring points in juxtaposition with the chamber surface, wherein at least two measuring points are located along a first axis passing through the center point and at least two measuring points are located along a second axis passing through the center point.