Patent ID: 6075464
Filing Date: 2000-06-13
Classification: G01B,G01D,G01F

Abstract:
Method for dynamic and non-contact measurement of a displacement of a grounded conductive substance with respect to a capacitive sensor formed of two parallel conductive plates, superimposed, electrically insulated one from the other, and fed by a high frequency signal at a predetermined voltage originating from a signal generator, said capacitive sensor being connected to a device for detecting a current value, said method comprising the steps of:(a) positioning said capacitive sensor close to and at a perpendicular fixed distance from a plane in which said conductive substance extends, said plates being substantially parallel to said plane, and displacing said conductive substance in said plane to modify an overlapping surface formed by portions of said conductive substance and said capacitive sensor which are superimposed;(b) detecting a current induced by said high frequency signal in said capacitive sensor, said current having a value varying in a directly proportional relationship with said overlapping surface; and(c) determining the value of the displacement of said conductive substance with respect to said capacitive sensor according to the value of said current,said conductive substance is a fluid contained in a tank, the displacement subjected to said measurement being the one of a level of said fluid in said tank in respect with said capacitive sensor.