Thermowells - Emerson Rosemount 248 Reference Manual

Reference Manual
00809-0100-4825, Rev CB
Thermal response time
9 seconds maximum required to reach 50% sensor response when tested in flowing water
according to IEC 751 or 12 seconds maximum required to reach 63.2% sensor response in water
flowing at 0.91 m/s (3 ft/s).
Immersion error
60 mm minimum usable depth of immersion when tested according to IEC 751.
Insulation resistance
500 megaohms minimum insulation resistance when measured at 500 V dc at room
temperature.
Sheath material
321 SST with mineral-insulated cable construction.
Lead wires
PTFE insulated, coated 22 gauge stranded copper wire.
A.2.4

Thermowells

Materials
Barstock Thermowells: 316L SST (1.4404)
Tubular Thermowells: 1.4571 (316 Ti)
Construction
Thermowell bodies are either machined from solid barstock or manufactured using swaged
tubes. Flange mounts are seal welded to the thermowell body with the exception of Class 900
flanges and above, which are full penetration welded. Surface finish of machined stems is 0.8
m (32  in. CLA.N6).
Material certification (option code Q8) and pressure testing (option code R01) are available.
Flanged thermowells generally conform to the specifications of ASME B 16.5 (ANSI), DIN 2519,
2527, 2633, 2635, and DIN 2526 Type C
Other thermowell materials and styles are available in Volume 1, 2, and 3 of the Temperature
Sensor and Accessories Product Data Sheet.
Specifications and Reference Data
Appendix A: Specifications and reference data
March 2014
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