Level Measurement Products Installation Considerations-Radar

Transcription

1 Siemens Industry, Inc / IA / Process Instruments Level Measurement Products Installation Considerations-Radar Restricted Siemens Industry, Inc All rights reserved. Answers for industry.

2 Radar Measures time of flight from transmitted signal to return signal for distance measurement and infer level. Pulse Advantage Non-contacting Insensitive to vapours and dust Unaffected by temperature and pressure Process connection flexibility Insensitive to acoustical or electrical noise Disadvantage Can be sensitive to foam Can be sensitive to very heavy condensate For closed metal or concrete vessels only Page 2

3 SITRANS Radar: Higher Frequency = Smaller Antenna Increased the frequency, yields: Increased precision Smaller antennas Tighter beam angle (less view of obstructions) Easier to install Better for solids (dust and fine granules) Potential negative effect of process conditions Build up Very High Humidity Turbulence 6 to 25 GHz best suited to liquids applications 25 to 78 GHz best suited to solids applications 6GHz 25GHz 78GHz 12 o 8 o 4 o Page 3

4 Beam angle Page 4

5 SITRANS Radar: Frequency, beam angle and skip 3 frequencies: 6GHz 25GHz 78GHz Smaller Antennae Easier installation 25 GHz 78 GHz 12 Guided wave radar SKIP & Beam angle Higher frequency Narrower beam 4 Higher frequency Less skip Page 5

6 SITRANS LR200 Radar: Effect of beam angle on installation 6GHz Min. clearance: 10 mm (0.4 ) Beam angle: 100 mm (4 ) rod = mm (6 ) rod = mm (8 ) rod = 28 4 horn = 29 6 horn = 20 8 horn = 17 Page 6

7 SITRANS LR250 Radar: Effect of beam angle on installation LR250 25GHz Min. clearance: 10 mm (0.4 ) Beam angle: 1.5 horn = 19 2 horn = 15 3 horn = 10 4 horn = 8 Page 7

8 SITRANS Radar: Effect of frequency on ease of use 6GHz 25GHz Page 8 Before After

9 SITRANS Radar: Effect of frequency on ease of use Comparison of 25 GHz versus 78 GHz on malted barley Wider beam of 25 GHz picks up seams of silo and requires fine-tuning SITRANS LR560 s 4 beam works with no adjustments plug and play 25 GHz 78 GHz Page 9 Before After

10 SITRANS Radar: Application Challenges Foam, Build-up and Turbulence LR200 (6GHz) better for some complex process applications Foam Deposit Turbulence 6GHz has a longer wavelength than 25GHz penetrates foam easier deposit has lesser effect better reflection from turbulent surfaces Page 10

11 Siemens Process Intelligence CLEF: Constrained Leading Edge Fit (liquids radar only) Low dk liquids at low levels produce a mixed signal that traditional radar will read empty at low levels. Traditional Radar Usually this occurs at levels below 0.5m (20 inches) Tank bottom echo appears below tank bottom due to slower propagation effect. Device reads Empty Page 11

12 Siemens Process Intelligence CLEF: Constrained Leading Edge Fit (liquids radar only) CLEF is a process where a Constrained leading edge fit curve is placed on the echo and the first echo of 2 joined echoes is extracted. Normally, COM (center of mass) is used for echo detection as it is more accurate. COM CLEF Device reads Level The CLEF is used only at the lowest level of the tank, default is 0.5m (20 inches) CLEF Range Page 12

13 Mounting Considerations Polarization axis Polarization reference point Polarization reference point For best results on a vessel with obstructions, orient the front or back of the device toward the obstructions. Display Page 13

14 Mounting Considerations Antenna Shield Nozzle considerations Rod antenna shield should extend 0.4 below nozzle 0.4 (10mm) 28 Page 14

15 Mounting Considerations Antenna Shield Nozzle considerations Rod antenna shield should extend 0.4 below nozzle Measure nozzle from inside 28 Page 15

16 Mounting Considerations Antenna Horn 0.4 (10mm) Nozzle considerations Most horn antennas should extend 0.4 below nozzle Measure nozzle from inside 8 Page 16

17 Mounting Considerations Nozzle considerations Most horn antennas should extend 0.4 below nozzle Measure nozzle from inside Page 17

18 Mounting Considerations Nozzle considerations Ensure nozzle does not interfere with beam path Page 18

19 Mounting Considerations Nozzle considerations Ensure nozzle does not interfere with beam path Use horn extensions when required Page 19

20 Mounting Considerations Aiming The sound path should be perpendicular to the monitored surface Flat for liquids and slurries Matching the angle of repose for solids Start by pointing across the draw point (30 max) Page 20

21 Mounting Considerations Aiming The sound path should be perpendicular to the monitored surface Flat for liquids and slurries Matching the angle of repose for solids Start by pointing across the draw point (20 max) Monitor through entire fill and empty cycles and adjust accordingly Page 21

22 Review Special features of ultrasonic and radar technologies Non-contacting Ease of installation no need to stop the process Virtually maintenance free Signal beam angles Process Intelligence Signal profiles Algorithms Auto False Echo Suppression Dynamic TVT Mounting considerations Siemens Industry, Inc / IA / Process Instruments Basic Non-contacting Theories Page 22

23 Basic Non-contacting Theories Questions? Page 23

24 Tim Bulbuk Siemens Application Engineer Siemens Process Instruments (517) Siemens Industry, Inc / IA / Process Instruments Thank You For Your Attention For Internal Use Only / Siemens AG All rights reserved. Page 24