Emerson Process Management MMI-20014120 manuale d’uso

Inst allation and Configuration Manual P/N MMI-20014120, Rev . AB August 2012 Micro Motion ® 3098 Gas S pecific Gravity Meter[...]

©2012, Micro Motion, Inc . All rights reserved. Micro Motion is a re gistered trade name o f Micro Motion, I nc., Boulder , Colorado . The Micro Motion and Emerson log os are trademarks and service mar ks of Emerson Electric Co. All other trademarks are property of their respective owners. Micro Motion pursues a pol icy of continuous developmen t [...]

Installation and Conf iguration Manual i Contents Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Safety guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Specific gravity measuremen t . . . . . . . . . . . . . . .[...]

ii Micro Motion 309 8 Gas Specific Gravity Met er Contents Chapter 4 Accuracy Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.1 Accuracy conside rations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.1.1 Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . . [...]

Installation and Conf iguration Manual iii Contents C .2 Ne w and unused e quipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 C .3 Used equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Appendix D Certified System Drawin gs . . . . . . [...]

iv Micro Motion 309 8 Gas Specific Gravity Met er Contents[...]

Installation and Conf iguration Manual 1 Installation Procedure A ccuracy Considerations Electrical Connections Intro duction Chapter 1 Introduction This chapter contains an outline of ho w the 3098 sp ecif ic gra vity meter works, defines some of the terms commonly used in the manu al, and also gi ves some practical applications for the 3098. 1.1 [...]

2 Micro Motion 309 8 Gas Specific Gravity Met er Introduction 1.2 Specific gravity measurement Most major gas flo w metering systems require th e metered quantity to be presented in heat or standard volume units. T o achie ve this requirement, it is often necessary to make continuous and accurate measurements of spec if ic gravity . Specific gravit[...]

Installation and Conf iguration Manual 3 Introduction Installation Procedure A ccuracy Considerations Electrical Connections Intro duction 1.3 Functional description Figure 1-2 Schematic diagram of a typical 3098 specific gravity measuring system The 3098 specif ic gravity meter consist s of a vibrating cylinder ga s density meter surrounded by a g[...]

4 Micro Motion 309 8 Gas Specific Gravity Met er Introduction If the sample gas pressure rises abov e that of th e reference chamber pressure, the pressure control v alve opens to v ent the excess gas via an outlet ori f ice in the enclosure side, so that the sample gas pressure is reduced to equal the re ference gas pressure. For gas to flo w it i[...]

Installation and Conf iguration Manual 5 Introduction Installation Procedure A ccuracy Considerations Electrical Connections Intro duction Figure 1-3 T ypical 3098 specific gravity measuring system 1.4 Definition of terms 1.4.1 Specific gravity Specific gra vity (G) is the ratio of the molecular weight of a gas (or gas mixture) to that of the molec[...]

6 Micro Motion 309 8 Gas Specific Gravity Met er Introduction 1.4.2 Standard (base o r normal) density Standard (base or normal) density ( ρ s ) is the absolute density of a gas at standard (base or normal) conditions o f temperature an d pressure an d is commonly u sed for standa rd volu mne flo w determination from mass flo w measurement. 1.4.3 [...]

Installation and Conf iguration Manual 7 Introduction Installation Procedure A ccuracy Considerations Electrical Connections Intro duction 1.5 Physical prop erties of gas compounds 1.6 Applications The follo wing are typical applications where specif ic gravity measurement is an essential parameter . 1.6.1 Supplementary gas su pply This system is u[...]

8 Micro Motion 309 8 Gas Specific Gravity Met er Introduction 1.6.2 Wob be index measurement The burning characteristic of a ga s must be well establis hed for eff icient combustion and to ensure that no flame lift or flame light-back occurs on a par ticular b urner . Three criteria are used to establish this characte ristic; calorif ic v alue, spe[...]

Installation and Conf iguration Manual 9 Installation Procedure Accuracy Considerations Electrical Connections Intro duction Chapter 2 Installation Procedure 2.1 Installation proce dure The procedure for installing the 30 98 in volv es the follo wing steps: 1. Check all components are present (Section 2 .2). 2. Position and f ix the 3098 enclosure [...]

10 Micro Motion 309 8 Gas Specific Gravity Met er Installation Procedure The 3098 specif ic gravity met er is contained inside an IP-rated enclo sure (which provides thermal insulation) and a mountin g system (consisting of a brack et and feet) to f ix the unit in place. While this structure is designed to min imize damage du e to shocks, the box a[...]

Installation and Conf iguration Manual 11 Installation Procedure Installation Procedure Accuracy Considerations Electrical Connections Intro duction 2.5 Reference chamber p ressure determination Once the 3098 specific gra vity meter ha s been placed in its fixture and all relev ant pipework and electrical connections made, the reference chamber pre[...]

12 Micro Motion 309 8 Gas Specific Gravity Met er Installation Procedure 2.6 Set-up pr ocedure – purge cycling and calibration Figure 2-2 Schematic diagram of a typical 3098 specific gravity measuring system The procedure for pur ging and calibrating the 3098 specif ic gravity met er is gi ven belo w (see Figure 2-2 for reference): 1. Ensure isol[...]

Installation and Conf iguration Manual 13 Installation Procedure Installation Procedure Accuracy Considerations Electrical Connections Intro duction Purge cycling 10. Close v alve C. 11. When Control Pressure Indicator is at the desired v alue, shut v alve A and open v alve F . Allow the gas to vent to atmospheric pressure. 12. Close v alve F and o[...]

14 Micro Motion 309 8 Gas Specific Gravity Met er Installation Procedure 27. Shut v alve B and disconnect the seco nd calibration gas bottle from pipe work. 28. Open the iso lation v alve D. 29. Open v alve A. 2.7 Outline dimensional drawings Figure 2-3 shows a 3098 specific gra vity meter witho ut an enclosure. For dimensions of small and large en[...]

Installation and Conf iguration Manual 15 Installation Procedure Installation Procedure Accuracy Considerations Electrical Connections Intro duction Figure 2-3 3098 specific gravity me ter without an enclosure Dimensions in inches (mm) ∅ 12.4 (314) ∅ 8 (203.2) 4.4 (112) 17.4 (442) 11.3 (286.4)[...]

16 Micro Motion 309 8 Gas Specific Gravity Met er Installation Procedure Figure 2-4 3098 specific gravity me ter with a small enclosure 20.3 (516) 19.7 (500) 12 (300) 1.2 (30) 1 / 3 (8.5) 20.3 (516) 17.1 (423) 17.1 (423) 19.7 (500) Dimensions in inches (mm)[...]

Installation and Conf iguration Manual 17 Installation Procedure Installation Procedure Accuracy Considerations Electrical Connections Intro duction Figure 2-5 3098 specific gravity mete r with a large enclosure 24.3 (616) 23.6 (600) 12 (300) 1.2 (30) 1 / 3 (8.5) 32.1 (816) 20.6 (523) 28.5 (723) 31.5 (800) Dimensions in inches (mm)[...]

18 Micro Motion 309 8 Gas Specific Gravity Met er Installation Procedure[...]

Installation and Conf iguration Manual 19 Installation Procedure A ccuracy Considerations Electrical Connections Intro duction Chapter 3 Electrical Connections This chapter contains details and wiring diagrams for connecting the 3098 specific gra vity meter to 7950/51 signal con verters an d flo w computers, and more generally to other eq uipment i[...]

20 Micro Motion 309 8 Gas Specific Gravity Met er Electrical Connectio ns Figure 3-2 Intercon nection diagram 3.2 EMC cabling and earthing T o meet the EC Directiv e for EMC (Electromagnetic Compatibility), it is r ecommended that the meter be connected using a su itable instrumentation cable an d earthed through the m eter body and pipew ork. The [...]

Installation and Conf iguration Manual 21 Electrical Connectio ns Installation Procedure A ccuracy Considerations Electrical Connections Intro duction Figure 3-3 Schema tic block diagram of meter circuit (2-wire system) Figure 3-4 Schema tic block diagram of meter circuit (3-wire system) 3.4 Use with signal converters and flow co mputers The meter [...]

22 Micro Motion 309 8 Gas Specific Gravity Met er Electrical Connectio ns When operat ing in a safe area with a 3-wire sy stem, the line resistance between meter and signal con verter must be greater than 40 ohms. This can be achiev ed by placing a suitable resistor in the line or by using the inherent resistance of the cable used (if the resistanc[...]

Installation and Conf iguration Manual 23 Electrical Connectio ns Installation Procedure A ccuracy Considerations Electrical Connections Intro duction Figure 3-7 7950 signal converter a nd gas specific gravity 2-wire system with galvanic isolator (hazardous area) Note: When the A TEX/IECEx-appr oved specif ic gravity meter is installed in a hazar d[...]

24 Micro Motion 309 8 Gas Specific Gravity Met er Electrical Connectio ns Figure 3-9 7950 signal converter and gas sp ecific gravity 3-wire system with shunt-diode safety barrier (hazardous area) Figure 3-10 7950 signal converter and gas sp ecific gravity 3-wire system with galvani c isolator (hazardous area) Note: The barrier trip level switc h sh[...]

Installation and Conf iguration Manual 25 Electrical Connectio ns Installation Procedure A ccuracy Considerations Electrical Connections Intro duction Figure 3-12 7951 flow computer/7951 signal converter gas specific gravity 2- wire system wi th shunt-diode safety barrier (hazardous are a) Figure 3-13 7951 flow computer/7951 signal converter gas sp[...]

26 Micro Motion 309 8 Gas Specific Gravity Met er Electrical Connectio ns 3.5.4 7951 3-wire co nfiguration Figure 3-14 7951 flow computer/7951 signal converter gas specific gravity 3-wire system (safe area) Figure 3-15 7951 flow computer/7951 signal converter gas specific gravity 3- wire system wi th shunt-diode safety barrier (hazardous are a) Fig[...]

Installation and Conf iguration Manual 27 Electrical Connectio ns Installation Procedure A ccuracy Considerations Electrical Connections Intro duction 3.6 System connections (customer’ s own equipment) 3.6.1 Non-hazardous areas Po wer supply to Density Meter: 15.5 to 33 Vdc, < 20 mA. Po wer supply to PR T : 5 mA maximum The frequency at which [...]

28 Micro Motion 309 8 Gas Specific Gravity Met er Electrical Connectio ns 3.6.4 Custo mer's equipment, 3-wire config uration Figure 3-19 Electrical connection s for meter 3-wire option used with customer’ s own equipment (safe area) Figure 3-20 Electrical connections for me ter 3-wire option used with custom ers’ own equipment an d shunt-d[...]

Installation and Conf iguration Manual 29 Installation Procedure Accuracy Considerations Electrical Connections Intro duction Chapter 4 Accuracy Considerations This chapter provides a method for estimating th e accuracy of 3098 specif ic gravity meter measurements under v arious conditions. 4.1 Accuracy consideration s The ‘controlled condition?[...]

30 Micro Motion 309 8 Gas Specific Gravity Met er Accuracy Considerations 4.1.3 Calculating parameters Density range at 20 °C Calculated using equation: Density meter temperature coefficient error In versely proportional to density (therefore pressure) and is calculated as follo ws: T emperature coef fici ent from calibration certificate = x kgm -[...]

Installation and Conf iguration Manual 31 Accuracy Considerations Installation Procedure Accuracy Considerations Electrical Connections Intro duction Installation Procedure Accuracy Considerations Electrical Connections Intr oduction Installation Procedure Accuracy Considerations Electrical Connections Intr oduction Installation Procedure Accuracy [...]

32 Micro Motion 309 8 Gas Specific Gravity Met er Accuracy Considerations W ith this decided, the 3098 specif ic gravity me ter can be calibrated by follo wing the calibration procedure described in Section 2.6. Note: In the case wher e only one calibration gas is availa ble, the time period of the density meter at zer o density/s pecific gravity ([...]

Installation and Conf iguration Manual 33 Accuracy Considerations Installation Procedure Accuracy Considerations Electrical Connections Intro duction Installation Procedure Accuracy Considerations Electrical Connections Intr oduction Installation Procedure Accuracy Considerations Electrical Connections Intr oduction Installation Procedure Accuracy [...]

34 Micro Motion 309 8 Gas Specific Gravity Met er Accuracy Considerations T E M P E R A T U R E C O E F F I C I E N T C A L I B R A T I O N C E R T I F I C A T E 3098 SPECIFIC GRAVITY METER Serial Numbers: Instrument 000001 Amplifier 000001 Cyclinder 000001 Pressure Test Units pressure tested to 300 p.s.i. g. Datum Periodic Time Time period with va[...]

Installation and Conf iguration Manual 35 Specification Maintenance and F ault Finding Chapter 5 Maintenance and Fault Finding 5.1 Introduction This chapter deals with the reco mmended serv icing and maintenance that can be carried out under field condi tions, including calibration checks, fault- f inding procedures and simple maintenance. If a fau[...]

36 Micro Motion 309 8 Gas Specific Gravity Met er Maintenance and Fault Finding 5.3.2 Instrument under -reads This is most probably due to a gas leak fro m the reference chamber . Before dismantling the instrument it is desirable to l ocate the leak, the cause of which may be one of the follo wing: (i) Reference chamber to sample gas path Parts af [...]

Installation and Conf iguration Manual 37 Maintenance and Fault Finding Specification Maintenance and F ault Finding If the erratic signal is only present while there is a f l o w o f s a m p l e g a s t h rough the unit, then the fault is likely to be due to a malfunction of th e pressure contro l va lve, brought abou t by the presence of dirt. In[...]

38 Micro Motion 309 8 Gas Specific Gravity Met er Maintenance and Fault Finding 5.4.1 Main meter (3098 specific gr avity meter) removal (Figure 5-1) The instructions in this section ap ply only to 3098 specif ic gravity meters supplied with an enclosure (see Safety guidelines o n page 1). In all oth e r cases, please refer to the system installer .[...]

Installation and Conf iguration Manual 39 Maintenance and Fault Finding Specification Maintenance and F ault Finding Figure 5-1 3098 specific gravity meter general a ssembly schematic (typical enclosure) 5.4.2 Density meter removal (Figure 5-2) 1. W ith the 3098 specific gra vity meter disconne cted and remov ed from its enclosure, the density mete[...]

40 Micro Motion 309 8 Gas Specific Gravity Met er Maintenance and Fault Finding 2. Use two of the remov ed M6 bolts to jack the meter from its housing using the tw o threaded holes found in the mounting housing (item 6). W ARNING! Do not try to lever the unit out – this will damage the sealing O-ri ng and the vibrating element. The aperture left [...]

Installation and Conf iguration Manual 41 Maintenance and Fault Finding Specification Maintenance and F ault Finding 4. Gently rest the 3098 specif ic gravity meter on its side and undo the six M6 bolts that lock the base plate to the reference cha mber . Note: Car e must be taken n ot to bend or dama ge th e thr ee gas pipelines that originate fr [...]

42 Micro Motion 309 8 Gas Specific Gravity Met er Maintenance and Fault Finding 6. Re-assembly is the re verse of steps 2 and 1 abo ve. Note: Once the unit has been r eplac ed into its enclosure , a leak chec k must be performed be for e on-line operation. 5.4.6 Further servicing of the density meter (Fig ure 5-5) Once the density meter has been re[...]

Installation and Conf iguration Manual 43 Maintenance and Fault Finding Specification Maintenance and F ault Finding 5.4.7 Leak testing the 3098 specific gravity meter Leaks incurred during servicing can be cate gorized under two main headings: • Reference chamber leaks a. Charge the reference chamber to 6.5 ba r G using any clean dry gas. b . Pa[...]

44 Micro Motion 309 8 Gas Specific Gravity Met er Maintenance and Fault Finding[...]

Installation and Conf iguration Manual 45 Specification Maintenance and F ault Finding Chapter 6 Specifications 6.1 3098 speci fic gravity meter specifications Note: Some parts of this specif ication (marked with *) cannot b e guarant eed for 3098 specif ic gravity meters supplied without an IP-rated enclosur e (see Safety guidelines on pa ge 1). 6[...]

46 Micro Motion 309 8 Gas Specific Gravity Met er Specifications 6.1.2 Electrical 6.1.3 Mechanical 6.1.4 Safety For A TEX/IECEx installations, see the A TEX/IECEx Safety Instructions booklet and PED Safety Instructions booklet (a v aila ble at www .micromotion.com). For CSA installations, see Appendix D. Ta b l e 6 - 2 Electrical specifications Spe[...]

Installation and Conf iguration Manual 47 Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Appendix A Performance Optimization A.1 Introduction The 3098 sp ecific gra vity meter uses a vibrating el ement density sens or that is located within a pressure regulating system. The a rrangement is such that the[...]

48 Micro Motion 309 8 Gas Specific Gravity Met er Performa nce Optimizat ion A.1.2 The non-ideal behaviour of gases This beha viour will af fect the operation of the me asurement system since the measurement of density at the operating condition is not on ly related to the relati ve dens ity of the gas b ut also to its compressibility factors. The [...]

Installation and Conf iguration Manual 49 Performa nce Optimizat ion Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization A.2 Recommended calibration methods From the previous descriptions it can be apprec iate d that there is a choice of calibration procedures. These differ in detail to suit the operating co[...]

50 Micro Motion 309 8 Gas Specific Gravity Met er Velocity of sound effect The velocity of sound effect on the sensor is such that: The velocity of sound in a gas can be determined as follo ws: For an ideal g as at 20°C, equation A2 can be simplified to: Therefore, substituting into equation A1 and simplifying: It follo ws that the VO S factor is [...]

Installation and Conf iguration Manual 51 Performa nce Optimizat ion Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Compressibility factor The normal or base de nsity ( ρ s ) is gi ven by the equation: The basic operation of the instrument allows the pr essure/temperature ratio to be considered constan[...]

52 Micro Motion 309 8 Gas Specific Gravity Met er Performa nce Optimizat ion The Z factors of the calibration gases and the sample gases should be calcul ated at both base and operating conditions in order to es tablish the compressi bility factor V F and then tab ulated as shown by the ex ample in Ta b l e A - 2 . Combination of V F and Z F By com[...]

Installation and Conf iguration Manual 53 Performa nce Optimizat ion Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Legend for T able A1 Summary This appendix describes the major systematic errors of the 3098 specif ic gra vity meters and methods of minimizing their effects by correct selection of the r[...]

54 Micro Motion 309 8 Gas Specific Gravity Met er Performa nce Optimizat ion T able A-1 At base conditions At sample gas conditions of ° C and bars 1 Gas type 2 Molecular mass M (1) (1) Column 2 data derived fr om p age x.x or other suitable tables. 3 γ at sample conditions (2) (2) Column 3 data is interpolated fr om International Standar d Gas T[...]

Installation and Conf iguration Manual 55 Performa nce Optimizat ion Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Ta b l e A - 2 At base conditions At sample gas conditions of ° C and bar s 1 Gas type 2 Molecular mass M (1) (1) Column 2 data derived fr om page x.x or other suitable tables. 3 γ at sa[...]

56 Micro Motion 309 8 Gas Specific Gravity Met er Performa nce Optimizat ion Example Calcul ations Column 5 Metha ne Nitrogen Sample A Sample B Sample C Column 6 Metha ne Nitrogen Sample A Sample B Sample C Column 7 Methane = 1+7(0.00017+6E –5x16.04–1.13E–5x16.0 4²+0) = 0.9876 Nitrogen 1 – 0.00023 8 x 7 = 0.9983 Sample A 1+7(0.00017+6E– [...]

Installation and Conf iguration Manual 57 Performa nce Optimizat ion Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Column 8 Methane = 0.9899 Nitrogen = 0.9988 Sample A = 0.9895 Sample B = 0.9896 Sample C = 0.9877 Column 9 Methane = 0.9816 Nitrogen = 0.9850 Sample A = 0.9807 Sample B = 0.9806 Sample C =[...]

58 Micro Motion 309 8 Gas Specific Gravity Met er Performa nce Optimizat ion An alternati ve method for deri ving modified v alues of Y to produce nil error is gi ven on the ne xt page. Column 12 Methane 0 Nitrogen 0 Sample A 0.13 Sample B 0.16 Sample C 0.54 Column 13 Methane = 0.9816 Nitrogen = 0.9712 Sample A = 0.9803 Sample B = 0.9798 Sample C 0[...]

Installation and Conf iguration Manual 59 Performa nce Optimizat ion Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Alternati ve simplif ied method of deriv ing modified v alues of Y (the nitrogen SG v alue used for calibration) to produce a nil e rror condition for a Methane/Gas C (or Gas B or Gas A) c[...]

60 Micro Motion 309 8 Gas Specific Gravity Met er Performa nce Optimizat ion[...]

Installation and Conf iguration Manual 61 Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Appendix B Principles of Operation B.1 Theory of specific gravity measurement By definition: The relati ve density is numerically equal to specif i c gravity when the superc ompressibility f actors of both the gas a[...]

62 Micro Motion 309 8 Gas Specific Gravity Met er Principl es of Operation Since conditions of constant volume and quantity e xis t for the reference gas, its density and molecular weight are constant an d from equation 5. If no w the two gases can be main tained at the same temperature, from equations 4 and 6: Finally , by using the sample gas (or[...]

Installation and Conf iguration Manual 63 Principles of Operation C er tified System Drawings Return P olicy Perf ormance Optimization Appendix C Return Policy C.1 General guidelines Micro Motion pro cedures must be followed when returning equipment. These proced ures ensure legal compliance with gov ernment transportation agencies and help pro vid[...]

64 Micro Motion 309 8 Gas Specific Gravity Met er Return Policy[...]

Installation and Conf iguration Manual 65 Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Appendix D Certified System Drawings D.1 General All certified dra wings in this manual are giv en here for planning purposes only . Before commencing with implementation, refere nce should always be made to the cur[...]

66 Micro Motion 309 8 Gas Specific Gravity Met er Certified System Drawings Figure D-1 CSA system drawing, gas gr oups A, B, C, and D (2-wire o ption) shunt diode barrier[...]

Installation and Conf iguration Manual 67 Certified System Drawings Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Pri[...]

68 Micro Motion 309 8 Gas Specific Gravity Met er Figure D-3 CSA system drawing, gas gr oups A, B, C, and D (2-wire o ption) isolating interface unit s[...]

Installation and Conf iguration Manual 69 Certified System Drawings Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Principles of Operation Cer tified System Dra wings Return P olicy Perf ormance Optimization Pri[...]

70 Micro Motion 309 8 Gas Specific Gravity Met er Certified System Drawings[...]

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