PORTABLE SENSOR FOR ELECTRICAL CAPACITANCE TOMOGRAPHY

摘要

AN ELECTRONIC CAPACITANCE TOMOGRAPHY SYSTEM IS ABLE TO OBTAIN INFORMATION ABOUT THE CONTENTS OF VESSELS, BASED ON MEASURING VARIATIONS IN THE DIELECTRIC PROPERTIES OF THE FLOWING MATERIAL INSIDE THE VESSEL. AN ELECTRONIC CAPACITANCE TOMOGRAPHY SYSTEM WORKS BY PLACING TWO ADJACENT CONDUCTORS ACROSS THE PIPE OR VESSEL TO BE EXAMINED; EFFECTIVELY CREATING A CAPACITOR. DIFFERENT DIELECTRIC PROPERTIES BETWEEN THE CONDUCTORS WILL CREATE DIFFERENT CAPACITOR VALUES. ACCORDINGLY, THE PRESENT INVENTION PROVIDES A SIGNAL CONDITIONING SYSTEM FOR ELECTRICAL CAPACITANCE TOMOGRAPHY, THE SIGNAL CONDITIONING SYSTEM (100) INCLUDES: AN ELECTRODE SENSOR (104); SIGNAL SWITCHING CIRCUIT WHICH IS CONTROLLED BY A SWITCHING CIRCUIT THAT IS FORMED BY CMOS ANALOG SWITCHES AND A MICROCONTROLLER CONTROLLER UNIT (110) THAT CONTROLS IT; A SIGNAL DETECTION AND AMPLIFIER CIRCUIT (120); A PROGRAMMABLE GAIN AMPLIFIER (PGA) WHICH IS USED TO AMPLIFY THE SIGNAL RECEIVED WITH A CONTROLLABLE GAIN, SUCH THAT THE MICROCONTROLLER CONTROL UNIT (110) SYNCHRONISES ALL THE OPERATIONS IN SIGNAL CONDITIONING SYSTEM (100) BY INTERFACING WITH CENTRAL CONTROL UNIT (101), SWITCHING ELECTRODE SENSOR (104) EITHER ACT AS SOURCE OR RECEIVER, CONTROLLING IC LIKE PROGRAMMABLE GAIN AMPLIFIER AND ANALOGUE TO DIGITAL CONVERTER (130)] CHARACTERIZED IN THAT, THE ELECTRODE SENSOR (104) IS BUILT FROM CONDUCTIVE PLATES WHICH ACTS AS A SENSING SURFACE THAT HAS DIRECT CONTACT TO MEASURING AREA, WHEREIN SAID ELECTRODE SENSOR (104) CAN BE BUILT UP FROM 8, 12, 16 OR MORE ELECTRODES MOUNTED SYMMETRICALLY INSIDE OR OUTSIDE AN INSULATION PIPE (200); WHEREIN AN ACTIVE LOW PASS FILTER (300) IS INTEGRATED INTO AN ABSOLUTE VALUE CIRCUIT (400), SUCH THAT RIPPLE SIGNAL IS FLATTENED AND RECTIFIED USING A CAPACITOR TO ELIMINATE NOISE FROM THE SIGNAL BEFORE FURTHER PROCESSING; AND WHEREIN THE ELECTRODE SENSOR (104) IS PLUGGABLE DIRECTLY ONTO A PLURALITY OF PRINTED CIRCUIT BOARD (PCB) SOCKETS OF THE SIGNAL CONDITIONING SYSTEM (100),