For use when standard thermowell design fails the ASME PTC 19.3 calculation
Kobe, Japan –?? End Users Thermowell specifications today include the phrase ASME PTC 19.3 that some suppliers and users wrongly use the word standard against this reference. Okazaki Manufacturing Company (OMC) fully recognise that ASME PTC 19.3 is in fact an ASME Performance Test Code not a design standard and should only be used to prove a standard thermowell design is suitable for the process conditions.
So, once the thermowell fails this Performance Test Code what can be offered? Currently, the only solutions have been to either shorten the thermowell immersion or increase the thermowell diameter, which is not always practical.
The other option offered by the majority of suppliers is to us a velocity collar to move the point of resonance. This is based on a very old UK (CEGB) power industry standard that used controlled bore weld in transitions and was never intended for the petrochemical industry where standard flange nozzle connections are the preferred choice.
This use of velocity collars requires that the thermowell is manufactured with high tolerance finish on the collar OD and that the corresponding nozzle is also machined to suit this high tolerance to insure a tight fit so no resonance can occur.
Fitting this type of collar increases firstly the thermowell cost and secondly the installation cost but more importantly, it m ust be installedt installed correctly; otherwise it can cause safety issues.
OMC has, through extensive R&D and independent evaluation, developed a new thermowell design VortexWell ?? which can safely be used when a standard thermowell fails the ASME Performance Test Code 19.3 with no special installation procedures.
Okazaki Manufacturing Company was founded in 1954 and started the design and manufacture of temperature related products in Kobe Japan. Okazaki has always been at the forefront of product design and the use of innovative technology. In 1963 OMC developed RESIOPAK which is a metal sheathed MgO insulated resistance thermometer which is now used worldwide for temperature measurement within the petrochemical industry and this design is replicated by many manufactures. Today OMC manufactures and designs an extensive range of reliable, highly accurate and extremely high quality products relating to the measurement and generation of temperature. with a turnover in excess of 110 Million USD. We are also one of the largest manufacturers of mineral insulated (MI) thermocouple and RTD cable which is the first building block of industrial temperature sensors.
Japan Head Office:
Okazaki Manufacturing Company
1-3 Gokodori, 3 Chome
Telephone +81 78 251 8200
Fax: +81 78 251 8210
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