Thermocouples
Thermocouples

Thermowell

Thermowell is a closed-end reentrant tube designed for insertion of a temperature-sensing element, and provided with means for a pressure-tight attachment to a vessel.

In this instance, the ASTM definition of thermowell leaves a bit to be desired. Thermowells are typically constructed of solid drilled-out bar stock and are designed to protect a temperature sensor from flow, high pressure and harsh environments. Thermowells encase and protect temperature sensors from the harmful effects of the processes into which they are immersed without substantially insulating the temperature sensor (thermocouple, RTD, etc.) from the temperature of the process.
The most common types of thermowells are:
•    Threaded : A threaded Thermowell is screwed into the process.
•    Socket Weld : A weld in Thermowell is welded directly into the process
•    Flanged Welded : A flanged Thermowell has a flange collar which is attached to a mating flange.
Features
•    A Process Connection
•    Shank Construction
•    A "Q Dimension"
•    Bore Size
•    Immersion ("U") length
•    Lagging extension ("T") length

Mineral Insulated Thermocouples 

Mineral Insulated Thermocouples & Resistance Temperature Detectors comprise of a metal sheath in which the thermo-electric elements/RTD element with conductors are embedded in highly compressed magnesium Oxide (MgO) insulation, thus providing the elements complete protection against oxidation and corrosion.

Thermocouples are available in type K, J, T, E, R, S, W, W3 and W5, simplex or duplex, in sheath diameters from 1mm to 19.05mm and length from a few cm to 200 meters or more. The hot junction is TIG welded and could be grounded (element hot junction welded to sheath tip giving faster response) or ungrounded (element insulated from sheath), one of which can be used as per control system requirement.


Applications
•    Steam
•    Steel
•    Cement
•    Salt Bath
•    Molten Metal
•    Process Furnace
•    Oven & Furnace with gaseous atmosphere plating

Specifications

Thermocouple Element

ANSI Type

Wire Dia. (mm)

Continuous Temp. Range °C

Max. Peak Temp. °C

Standard Limits of Error

Base Metal
Fe. /Constn.

J

1.38/1.5
2.5
3.2

-150.... 600
-150.... 600
-150.... 700

950

± 2.2°C upto 293 °C

&

± 0.75% above 293 °C

Chromel/Alumel or NiCr/Ni

K

1.38
1.63/2.0
2.5/3.2

-150....900
-150....1100
-150....1200

1260

Rare Metal
PL.10% Rh./Pt.
Pt. 13% Rh./Pt.

S

R

0.33
0.45
0.50

 0....1300
 0....1500
 0....1600

1600

± 3°C/ 0.5%
whichever is higher

Pt.13% Rh./Pt
6% Rh

B

0.33
0.45
0.50

 100....1500
 100....1600
 100....1700

1800

± 0.5% above 800°C

For detailed specifications please contact us.