Wilockx Chris. Level Basics

Transcription

1 Wilockx Chris Level Basics

2 Physical Basics of Pressure Measurement F (force) N (Newton) P (pressure) = = Pa A (surface) m2 There are different pressure units: kpa: kilo Pascal mmhg: mm mercury bar: bar atm: atmosphere kg/cm2: psi: pound/inch2 mmh2o: mm water inh2o: inch water

3 Physical Basics of Pressure Measurement Pressure Quantity Absolute Pressure Atmospheric Pressure Gauge Pressure Differential Pressure Symbol pabs pamb pe dp pabs1 pe1 > 0 dp 0% pe = 0 pamb. pe2 < 0 pabs % pabs = 0 (Vacum)

4 Physical Basics of Pressure Measurement Pressure is equal in all directions Hydrostatic Paradox P = S.g.h S = Rho = density Pa = kg/m3. 9,81m/s2. m

5 Pressure Measurement Pressure U - Tube U-Tube Pa = S.g.h + P0 Pa = kg/m3. 9,81m/s2. m

6 Pressure Measurement Pressure Transmitters Boudon pressure gauge

7 Pressure Measurement Pressure Transmitters p - measurement dp - measurement

8 Functional Principle of P and dp Transmitters Conversion of the Physical Factor (i.e.: Deflection of Diaphragm) into an Electrical Factor: Different sensors are used: Inductive measuring principle (coil) Capacitive measuring principle (capacitor) Strain Gauge measuring principle (Bridge) Piezo-resistive measuring principle (chip)

9 Functional principle of P and dp transmitters inductive measuring principle: n2. A L = µ l

10 Functional principle of P and dp transmitters capacitive measuring principle: diaphragm P1 P2 E. A C = d C1 C2 Glass Measuring diaphragm

11 Functional principle of P and dp transmitters Strain Gauge measuring principle : R = K x R Metal cores Strain gages array (bonded or made directly on the substrate) + Measuring diaphragm Substrate x Bonding

12 Functional principle of P and dp transmitters piezo-resistive measuring principle (example 265D) : DP-Sensor P abs -Sensor Measuring of resistance change via crystal lattice displacement

13 Functional principle of P and dp transmitters piezo-resistive measuring principle (e.g. 265G) : lower range value span write protect measuring mechanism Microprocessor based electronics matching Measuring of resistance change via crystal lattice displacement isolating diaphragm P e -Sensor

14 Main Components terminal blocks housing push buttons secondary electronics integral display covers display covers vents transducer gaskets bolts flanges

15 Functional Specifications General Base accuracy: ABB Model 265/266 +/- 0,04% ABB Model 264 +/- 0,075% Turn Down: 1/100 Ranges ABB Model 265 Pressure Transmitters: 60mbar - 400mbar mbar - 10bar - 30bar - 100bar 600bar Ranges ABB Model 265 dp Transmitters: 10mbar - 60mbar - 400mbar 2500mbar - 20bar 100bar

16 Level Measurement Different mounting positions? open to atmosphere P = S.g.h h Dead zone Open tank liquid measurement

17 Level Closed Tank N2 If the level to be maeasured is in a closed tank, a dp transmitter is necessary. max. level h1 S Dry Leg S = 0? min. level Wet Leg h2 transmitter reference line 4 ma = S. g. h2 20 ma = S. g. (h2 + h1) S = specific gravity (medium)

18 Level Closed Tank If the level to be maeasured is in a closed tank, a dp transmitter is necessary. max. level h1 S1 h4 Glycol S2 Wet Leg min. level Wet Leg h2 transmitter reference line 4 ma = S1. g. h2 S2. g. h4 20 ma = S1. g (h1 + h2) S2. g. h4 S1 = specific gravity (medium) S2 = specific gravity (Wet leg)

19 Level Closed Tank If condensable vapours are present use the following installation. filling tee 0 max. level min. level h1 S1 impuls line filled with stable fluid (Wet Leg) S2 h4 transmitter reference line h2 transmitter reference line 4 ma = S1. g. h2 S2. g. h4 20 ma = S1. g (h1 + h2) S2. g. h4 S1 = specific gravity (medium) S2 = specific gravity (Wet leg)

20 hlow hhigh h Boiler-Level Measuement Ordering data: dp transmitter with adjusted value of 300mm mm (WC) Actual requirement: boiler level measurement level to be monitored: -300 mm mm Distance between connection pipes: h = 1000mm Density water Tuper.: +200 C (Sup= 865 kg/m 3 ) hlow (hlow) = 200mm Tref.: +30 C (Sref= 996 kg/m 3 ) hhigh (hhigh) = 800mm +300 mm Density steam Tsteam.: +200 C (Ssteam = 7.9 kg/m 3 ) NN mm

21 hl hh H Boiler-Level Measuement DP Transmitter with an adjusted value of: mm (WC) h +300 mm mm P1 (-300mm) = (-h* Sref * g + hl * Super. * g + [h-hl] * Ssteam * g) * 10 2 = = (-1 * 996 * * 865 * * 7.9 * 9.81) * 10 2 = mbar P2 (+300mm) = (-h* Sref * g + hh * Super. * g + [h-hh] * Ssteam * g) * 10 2 = = (-1 * 996 * * 865 * * 7.9 * 9.81) * 10 2 = mbar Adjusted value: mbar

22 Remote Seals Protect Transmitters from Useful for High temperature Corrosive components Media with high viscosities Media with tendency to polymerization Prevention of deposits in the process Connection Adaptation to various process connections

23 Level Open Tank e.g.: a seal transmitter flange mounted on the high pressure side of the transmitter is recommended in case of dirty liquid fluid or process temperature > 107 C transmitter reference line P = S. g. h

24 Level Closed Tank max. level h1 N2 e.g.: a seal transmitter flange mounted on the high pressure side of the transmitter is recommended in case of dirty liquid fluid or process temperature > 107 C min. level h2 min. level may not be below this line transmitter reference line

25 Level Closed Tank Sg low side seal reference line max. level filled capillary min. level h1 h4 Sc h2 S high side seal reference line h3 4 ma = S. g. h2 + Sg. G.(h4-h2) Sc. g. h4 20 ma = S. g. (h1 + h2) Sc. g. h4 S = specific gravity (medium) Sg = specific gravity (gas above fluid) Sc = specific gravity (filling oil capillary tube) transmitter reference line

26 Level Transmitter 265D Compact Version

27 Remote Seals Design... with Flush or Extended Diaphragm in Flange design DN 25 Pressure Rating PN 10...PN 250 DN 50 / DN 80 Pressure Rating PN 16...PN 100 DN 1 DN 2 / DN 3 Pressure Rating 150 psi psi Pressure Rating 150 psi psi

28 Remote Seals... via Capillary Tube to Transmitter

29 Remote Seals Design... with Flush or Extended Diaphragm in Sandwich Design DN 50 / DN 80 Pressure Rating up to PN 400 DN 2 / DN 3 Pressure Rating up to 2500 psi

30 Remote Seals Design Corrosion Resistant Materials Stainless Steel Hastelloy C Monel 400 Tantal FEP coated Gold plated Ect Capillary tube stainless steel, with PVC protective cover as an option

31 Remote Seals Design Filling liquids depending on the application Silicon Oil Carbon Fluoride White Oil High Temperature Oil as Standard for Oxygen Service for Food and Beverage up to 400 C Vacuum proof design with special liquid for use down to an absolute pressure of 5 mbar abs. ABB is a recognized leader in the all welded technology where Remote Seals System can be welded at every junction.

32 Application Limits Filling Liquid Id Pressure rating in mbar abs. 20 C (68 F) 100 C (212 F) 150 C (302 F) 200 C (392 F) 250 C (482 F) 400 C (752 F) Silicone Oil IC > 500 > 500 > 500 > 750 > Carbon Fluoride High-temperature Oil L IH > 1000 > 1000 > > 500 > 500 > 500 > > 1000 > 1000 White Oil WB > 500 > 1000 > 1000 > 1000 > Vacuumproof Design IC-V > 5 > 25 > 38 >

33 Application Limits

34 Seals Design Performance Accuracy is primarily affected by Fill volume change due to temperature Capillary length Diaphragm stiffness Low fill volume and low stiffness of diaphragm is required for high accuracy

35 Questionaire

36 Questionaire for P-/DP-Transm. with remote seals

37 Level Measurement air supply regulator dp h Bubble measurement

38 Liquid Level (example oil on water) S2 range of interface level interface level h S3 S1 LT S1 = H 2 O S2 = oil 4 ma = S2. 9,81. h (only oil) 20 ma = S1. 9,81. h (only H 2 O) (simplified illustration; without the influence of capillary tube S3) Interface level measurement

39 Density S1 = low specific gravity S2 = higher specific gravity S3 = specific gravity of filling oil in capillary tube 4 ma = (S1. h S3. h) ma = (h * SG2 h * SG3) * 9.81 h Density measurement

40 output (volume) Level measuement in a spheric tank Input [%] (Level = h) Ouput [%] (Volume) v = 1/3 pi * h 2 (3r h) input (level = h)

41 Level measuement - warning Pressure (vacuum) Temperature Medium Foam Agitator Flow inlet

42 Intelligent Transmitters Conventional 1965 A E ma HART 1987 A E + # ma + superimposed, digital communication Fieldbus 1985/95/97/99 A # FSK-Modem

43 Functionality Intelligent Transmitters Fieldbus Traditional Value HART Value Device Parameter More values Multi variabel High resolution Diagnostic data Quality signal Status Decentral Functions Distributed Control Bi-directional Asset Optimization Graphics 4-20mA SMART Fieldbus Time

44 Intelligent Transmitters Value (measuring) Status Scaling Filter time Alarm / warn limits Alarm summary TAG Cyclic services (Analog value) Acyclic services (Hart) Device diagnostic Manufacture specific parameter Spontaneous services Acyclic services

45 Basic range value Sensor range limits Floating Point 32 bit Intelligent Transmitters 400 mbar Analog Technology Bus Technology 200 mbar 20 ma 0 mbar 4 ma -400 mbar

46 Communication mode: Point-to-Point 2600T e.g. power supply FSK modem U S > V DC (HART) R > 250 Ohms

47 Communication mode: FSK Bus 2600T TZN 128 e.g. power supply FSK modem TZN 128 FSK modem

48 SmartVision

49 SmartVision

50 SmartVision

51 Communication Requirements Connecting cable Communication between transmitter and PC/laptop requires shielded and twisted pair lines. The minimum wire diameter should be: mm for lines up to 1500 m mm for lines longer than 1500 m The maximum line length is limited to: m for twin-core cable m for multicore cable

52 Electrical Safety - Explosion Protection The areas where this can occur are classified depending upon the probability that gas/vapour, in dangerous combination with air, is present. In Europe and some part of the world, except the American continent, the classification is as follows, according to IEC Publication 79-10: ZONE 0: an area in which an explosive gas-air mixture is present continuously or for long periods. ZONE 1: an area in which an explosive gas-air mixture is likely to occur in normal operation. ZONE 2: an area in which an explosive gas-air mixture is not likely to occur in normal operation, and if it occurs, it will exist only for a short time.

53 Electrical Safety - Explosion Protection In North America, the classification refers to only two divisions, which may be briefly defined as follows, according to NEC article 500: Division 1: hazard may be present in normal operation. Division 2: hazard may be present only in abnormal operation. Therefore the following rough equivalence apply: CONTINUOUS HAZARD (> 100 h / y) INTERMITTENT HAZARD (1-100 h / y) ABNORMAL CONDITIONS ( h / y) EUROPE (IEC) ZONE 0 ZONE 1 ZONE 2 North America * DIVISION 1 DIVISION 1 *Note: The Zone classification like IEC is now possible also for North America according to article 505 of the NEC/Edition 1996, ANSI/NFPA70

54 Electrical Safety - Explosion Protection The various gases/vapours are grouped considering their "likeness" in terms of ignition energy. Each group has a "representative gas". Representative gases and relevant minimum ignition energy (microjouls) are shown here below: Representative Gas IEC / CENELEC (EUROPE) NORTH AMERICA Minimum Ignition Energy [micro joules] Acetylene II C Class I Group A 20 µj Hydrogen II C Class I Group B 20 µj Ethylene II B Class I Group C 60 µj Propane II A Class I Group D 180 µj Note: according to IEC classification II means surface industries (as an alternative to mining atmosphere)

55 Electrical Safety - Explosion Protection The temperature classification relates to the maximum attainable temperature of the transmitter, or part of it (normally assuming a 40 C ambient), to the ignition temperature of a gas / vapour. Max. Temp. North America Max. Temp. IEC/CENELEC [ C] [ C] (EUROPE) 200 T3 180 T3A 165 T3B 160 T3C 135 T4 450 T1 300 T2 200 T3 135 T4 100 T5 85 T6

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