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Teflon Vs Fibreglass

ianchan

#19682

Teflon Vs Fibreglass | 25 April, 2002

We have an internal debate whether to calibrate equipment using K-type thermocouple made out of :

1) fibreglass braided, with a 482 deg-C peak-measurement properties?

2) teflon FEP(fluorinated Ethylene Proplene), with 204 deg-C peak-measurement properties?

For my side, am assuming the guys who wanna use fibreglass types of thermocouples, want greater process control window? yet, calibration has always been using teflon types as far as I can say... and yep, we know it all can be linked to what is the peak temperature required to be measured? currently the specs called for (deg-C) as requirements is -ve/200 deg-C to +ve/1370 deg-C. its a digital scientific lab thermometer.

Can anyone help shed some light, is there any apparent advantages in using K-type thermocouples made out of fibreglass Vs conventional teflon types?

speed in reply is appreciated, as we need to send out the equipment for calibration, ASAP.

Thanks in advance, mates!

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#19688

Teflon Vs Fibreglass | 25 April, 2002

Oh great!!! You do calibrations, what once a year? And NOW yer in a BIG �time is critical� rush. �Speed in reply is appreciated.� And why couldn�t you have asked this question 6 months ago? Just what have you been doing since the last calibration?

A thermocouple is made by welding two wires of different metals together. Thermocouple Type||Materials B||Platinum30% Rhodium (+) Platinum 6% Rhodium (-) C||W5Re Tungsten 5% Rhenium (+) W26Re Tungsten 26% Rhenium (-) E||Chromel (+) Constantan (-) J||Iron (+) Constantan (-) K||Chromel (+) Alumel (-) N||Nicrosil (+) Nisil (-) R||Platinum 13% Rhodium (+) Platinum (-) S||Platinum 10% Rhodium (+) Platinum (-) T||Copper (+) Constantan (-)

When you purchase a thermocouple, you must tell the sales-type the following: * Thermocouple type [ie, J, K, E, T, etc]. * Wire size range, may be 0.0100 to 0.1285 inch * Sheath material [ie, Inconel, stainless steel, PTFE, etc]. * Sheath diameter [ie, 1/16 inch, 1/8 inch, 3/16 inch, 1/4 inch, etc]. * Thermocouple junction [ie, exposed, grounded, ungrounded, etc]. * Sheath length [ie, 12 inch, 24 inch, etc]. * Connector type [ie, BNC, SMB, banana jack, thermocouple plug, 9-pin D-Sub connector, none, etc].

The measuring temperature is limited only by thermocouple type and sheath material. * Type K is appropriate for a temperature range of 32 to 2,300�F (0 to 1,259.99�C). Look here http://www.conaxbuffalo.com/tech/emf/TypeKF.pdf

* Sheath material include http://www.conaxbuffalo.com/tech/Sheath.pdf http://www.conaxbuffalo.com/tech/CSG.pdf

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ianchan

#19690

Teflon Vs Fibreglass | 25 April, 2002

Hi Dave,

Bbbaaa....*note the sheep eyes*....bbaaa....

ok, that was a great wakep up rap! I'll relay that strongly worded paragraph to the calibration in-charge, see what he has to say for himself? thing is, such situations reflects on us as a whole company.

PS: thanks for the web links.

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