Siemens Sitrans F FX300 Manual De Usuario

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 DEVICE DESCRIPTION 
2
15
SITRANS FX300
www.siemens.com/flow
06/2009 - SFIDK.PS.050.F2.02   A5E02100423
2.2.6  Dual seal
To cover the requirements of ANSI/ISA-12.27.01-2003 “Requirements for Process Sealing 
Between Electrical Systems and Flammable or Combustible Process Fluid” Dual seal, a 
membrane vent is integrated in the neck of the instrument. This vent works  in the improbable 
case of a leakage as an annunciation valve between the primary seal (Process) and secondary 
seal (electronic compartment). 
The sealing between the pick-up and the Flow tube  is considered as the primary seal. Its 
construction material is always the same as the Flow tube itself (e.g. Stainless steel 316L or 
Hastelloy C22). Chemicals used for the process, going through the Flow tube, must be 
compatible with the designated material.
By using the membrane vent as annunciation valve, all requirements for a dual seal device in 
accordance to above mentioned standard, are fulfilled.
• It protects the electronic compartment against access by process media, due to possible 
leakages.
• The leakage of the primary seal is visible.
Regular maintenance should be performed by the customer to ensure this Dual Seal notification 
system is working properly or that there is no leak.
If a leakage is noticed:
Siemens customer service should be contacted for servicing or replacement of the meter.
1  Annunciation valve (Membrane vent)
MA_Siemens_Sitrans_FX300_R02_en_PRT.book  Page 15  Monday, June 22, 2009  8:17 AM