Emerson 3098 Manuel D’Utilisation

4.1 Accuracy 

considerations......................................................................................................4-1 

4.2 

Calibration (for non-natural gas applications) ......................................................................4-4 

4.2.1 

Operation at low reference pressure levels ...........................................................4-4 

5.1 Introduction..........................................................................................................................5-1 

5.1.1 Calibration 

check ...................................................................................................5-1 

5.1.2 Faultfinding ............................................................................................................5-1

5.2 Maintenance ........................................................................................................................5-4 

5.2.1 

Main meter (3098) removal ...................................................................................5-4 

5.2.2 Density 

meter 

removal...........................................................................................5-6 

5.2.3 Reference 

chamber 

diaphragm 

removal ...............................................................5-7 

5.2.4 Re-assembly 

procedure ........................................................................................5-8 

5.2.5 

3098 filter change procedure .................................................................................5-8 

5.2.6 

Further servicing of the density meter ...................................................................5-9 

5.2.7 Leak 

testing 

the 

3098 ..........................................................................................5-10 

5.2.8 Post 

maintenance 

tests .......................................................................................5-10 

5.2.9 

Worked example of calibration certificate ............................................................5-10 

6.1 3098 

specification................................................................................................................6-1 

6.1.1 Performance..........................................................................................................6-1

6.1.2 Electrical................................................................................................................6-1 

6.1.3 Mechanical ............................................................................................................6-1

6.1.4 Safety ....................................................................................................................6-2 

A.1 Introduction......................................................................................................................... A-1 

A.1.1 The 

density sensor ............................................................................................... A-1 

A.1.2 

The non-ideal behaviour of gases ........................................................................ A-1 

A.1.3 

Selection of reference chamber pressure ............................................................. A-1 

A.1.4 Selection 

of 

calibration gases ............................................................................... A-2 

A.2 Recommended 

calibration 

methods ................................................................................... A-2

A.2.1 General 

calibration 

method .................................................................................. A-2

A.2.2 Specific 

calibration 

method................................................................................... A-2

B.1 

Theory – specific gravity measurement .............................................................................. B-1