1. Conventional Solid Measurement Techniques - Narrow Beam Angle -Only Single Point Measurement -Affected By Dust And Moisture

2. Solution To All the Problems Described in Previous Slide LOW FREQUENCY 3D ACOUSTICS 3D LEVEL SCANNER

3. Low Frequency and Dust Penetration Chart Ultrasonic Sonic ( 3-4 KHz) 3dB Loss is 50% Loss of Signal Energy

4. Low Frequency and Dust Penetration Sound is a pressure wave Dust particles and Humidity in air attenuate the wave energy Attenuation grows sharply over 5 kHz Low Frequency => Effective Dust Penetration Principle Behind Effective Dust penetration : DIFFRACTION around a particle of size less than its wavelength

5. Beam Angle vs. Frequency θ - Beam opening angle λ - Wavelength D - Antenna size Low Frequency => Wide Beam Angle

6. F = 4.5KHz λ = 7.5cm θ = 60 ⁰ F = 2.5KHz λ = 13cm θ = 108 ⁰ F = 10KHz λ = 3.4cm θ = 27 ⁰ F = 20KHz λ = 1.7cm θ = 13 ⁰

7. Low Frequency Acoustics and Self Cleaning Ability Low Frequency acoustic vibrations prevents sticking of material to the internal working of the device Ensures long term reliable performance in harsh dusty conditions

8. Low frequency has 4 major advantages Very low attenuation Easy penetration through dust Wide angle that covers the whole silo (70-80 degrees) Acoustic vibrations contribute towards the self cleaning ability

9. 3D Surface mapping requires a 2D array 2 Dimensional Array of 3 Antenna Estimating per echo: – Distance (R), Azimuth (Ф) and Elevation (Θ) angles – Convert R, Ф, Θ to Silo X,Y,Z coordinates Final surface reconstruction, based on – Extreme and boundary points – The Material angle of repose – The silo geometry – Acoustics principles 3 Dimensional Surface Reconstruction Working Principle

10. COAL BUNKERS/ FLY ASH / CEMENT/ CLINKER SILOS WARE HOUSES/ OPEN STOCKPILES FERTILIZER/ CHEMICAL SILOS

11. 3D Representation of the Device