Method and device for rapid non-destructive quality control of powdered materials

A method of non-destructive testing for quality control of powdered materials having dielectric properties, said method based on the use of electromagnetic capacitance techniques, and comprised of the following steps:

• switching on a generator of an electric field driving a transducer that is not in contact with a samples of the powder to be tested;
• measurement of the self-capacitance and Q-factor of the resonance circuit with a capacitive sensor, which is located in the local ambient environment;
• obtaining the computed operational parameters of said transducer electric circuit and sending them to the main unit for processing, storage, analysis and display;
• switching off said generator of electric field for said transducer without sample powder;
• positioning said sensor on the surface of the material to be tested, switching on an impulse generator to provide power for a vibrating electromagnetic transducer and/or immersing the sensor into the material to be tested;
• shutting off of ultrasound generated for the vibrating electromagnetic transducer after the sensor has been fully immersed in the material to be tested;
• switching on said generator of electric field for the transducer after said transducer has been fully immersed in the material to be tested;
• measuring the phase shift caused by the effect of the powdered material being tested on the real and imaginary components of the impedance of said capacitance sensor;
• measuring the frequency shift of the resonance circuit, containing said capacitive sensor, caused by the effect of the dielectric permeability of the powdered material upon the capacitance of said sensor;
• determining capacitance of said sensor, which has been fully immersed in powdered material, by the value of the frequency shift;
• determining the appropriate correcting signal for the phase shift;
• determining the informative signal, which describes the magnitude of dielectric losses in the field of said sensor in contact with the powdered material to be tested;
• transforming parameters of said sensor with powder in said electronic circuit of said sensor and sending them to the main unit for processing, storage, analysis and display;
• removing the sensor from the powdered material being tested;
• switching on the source of ultrasonic oscillation while removing the sensor from the powdered material to clean electrodes of the sensor of residual powder until the values of Q-factor of said resonance circuit, together with said capacitive sensor, reaches a predetermined threshold values;
• making measuring from other areas on the surface of powdered materials and obtaining averages for all said measurements;
• determining the of quality of the powdered material by taking the average of the informative signal value for all measurements.