Indholdsmåling Dalum Landbrugsskole Vejeevent 21. august 2018 Siemens.com/level
Indholdsmåling Page 2
Level Signal Indholdsmåling Two groups of level measurement: Continuous measurement of material at all times Point measurement (Blue trend) Continuous measurement (Green trend) Time Remember Good practice is to apply back-up or redundant point level control when applying continuous level measurement. Point measurement of material when in contact Page 3 There is often an opportunity and advantages to applying continuous level measurement when applying point level control.
Indholdsmåling kontinuert Level Space Distance Volume Page 4
Indholdsmåling udfordringer! Split silo with supports Narrow Wetwell Foam Build up Agitator Blades Page 5 Condensation Turbulance Vapor or steam
Indholdsmåling punkt Page 6
Point Level Technology considerations RF Capacitance The Siemens approach to capacitance is based on the following principle: Vibration Crystal stack vibrates forks Vibration also sensed by crystal stack Material contact damps vibration Receive crystal measures change in vibration Switch is activated 5 MHz 1 MHz Air (Empty Vessel) Crude Emulsion Water Ignored Set threshold Detected Paddle rotation Motorized paddle rotates in free-air 1RPM or 5RPM option Material contact stops rotation Transferred torque activates switch Motor is stopped during switched state Page 7 Capacitance range
Point Level Siemens portfolio overview RF Capacitance Vibrating Fork Rotating Paddle CLS100 LVL100 LPS200 LVL200 Ultrasonic CLS200 LVS100 Page 8 CLS300 LVS200 ULS200
Indholdsmåling ultralyd Page 9
Ultrasonic Technology considerations Speed of Sound vs. Temperature Speed of sound varies with temperature and must be compensated ~0.17% error per meter per C Siemens ultrasonics measure temperature and compensate for changes in speed of sound Siemens Ultrasonics have a Self-Cleaning Face! NO fouling (condensation) NO build-up NO deposit Attenuation of sound in different atmospheres Speed of sound varies with atmospheres other than air Sound does not propagate in some atmospheres (e.g. carbon dioxide, vacuum) and therefore alternative technologies are required. Siemens ultrasonics can be calibrated in many atmospheres other than air Page 10 Submergence detection If ever the transducer is submerged Submergence kit allows pump monitoring during submergence
Ultrasonic Siemens portfolio overview Transmitters Controllers Transducers LU150 LU180 LUT400 EchoMax Probe LU Page 11 MultiRanger
Indholdsmåling radar Page 12
Radar Technology considerations Increasing the frequency you get: Increased precision required in manufacture 3 frequencies: 6GHz Smaller Antenna 78 GHz 25 GHz Guided wave radar Smaller antenna 25GHz Easier installation Tighter beam angle (less view of obstructions) Easier to install 78GHz 12 Better for solids (dust and fine granules) Potential negative effect of process conditions SKIP & Beam angle Higher frequency Narrower beam Build up Foam 4 Page 13 Higher frequency Less skip
Radar Siemens portfolio overview Liquids Solids Probe LR LR200 LR260 LR460 Page 14 LR250 LR560
Indholdsmåling guided radar Page 15
Guided Wave Radar Technology considerations Guided Wave Radar (GWR) uses the principle of Time Domain Reflectometry (TDR), where pulses of high frequency energy are sent down a wave guide (probe or cable) and precision timing circuitry measures the reflection of the signal off the surface of the process. A return echo is reflected from the surface Transmit pulse Air dk = 1 (dk = dielectric constant) Pulses of high frequency energy are sent down the probe (wave guide) every second Media dk 1.4 to 100 A small amount of energy continues along the probe in low dk fluids (eg: Hydrocarbons) Page 16
Guided Wave Radar Applications Ideal for horizontal cylinders Measurement in side pipes/bypass Liquid interface Page 17 Applications with steam or ammonia Applications with turbulence Medium range solids
Guided Wave Radar Siemens portfolio overview Liquids Solids LG240 LG270 LG250 LG260 Page 18
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