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Rosemount™ 91 Thermowell (Obsolete)
This product is now obsolete.
Relevant documents and drawings are listed below.
Contact your local Emerson representative for your measurement needs.
Rosemount™ 91 Thermowell (Obsolete)


Thermowell Calculations
Wake frequency calculation (WFC) performed by certified engineers, order R21 for official report
Material certification, NACE, CRN (see full specs for complete list of certifications)
Product Tests
External pressure test, internal pressure test, dye penetration test


  • Available in threaded, flanged, welded or sanitary mounting styles for application flexibility
  • Straight, tapered or stepped stem profiles to meet process requirements
  • Large selection of thermowell materials to ensure compatibility with the process and process piping
  • Optional Wake Frequency Calculation report verifies process compatibility
  • Available with NACE approval to meet MR0175/ISO 15156 and MR0103 requirements for sour gas applications
  • External pressure test option confirms structural quality and checks for leaks at thermowell connection and stem