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mineral insulated (mgo) Thermocouples

magnesium oxide (mgo) insulated Thermocouples

Single

Conductors

Duplex

Triplex

MGO Insulation

Sheath

mgo thermocouples oer the greatest variety of features of all styles of thermocouples making them the best choice for most applications. They are made in all calibrations with a wide variety of sheath diameters and materials. MgO assemblies are fully an- nealed and eld bendable. They can be bent to a minimum radius of twice the sheath diameter without damage to the insulation and mounting hardware can be brazed or welded to the sheath.

MgO sensors are recommended where a moisture proof, non-porous insulation is required, and for applications where high pressure, high vibration and high temperature conditions are en- countered. These variations make them the logical choice for applications from test labs to heavy industry.

GIC uses only High Purity MgO in our assemblies which is recommended for high temperature applications. MgO lled metal insulated thermocouples are available in sizes from 0.010 to 0.500 inch diameters. Choosing the proper diameter for an application depends on the process envi- ronment, process temperatures, and desired response time. A good rule to consider is the higher the temperature the larger the diameter probe. Also, the faster the response time required the smaller the diameter, providing high temperatures are not involved. For ungrounded sensor with

approxim

ate mgo res

ponse times

MgO Diameter

Grounded Junction

Ungrounded Junction

.020 .032 .040 .063 .090 .125 .188 .250

.10 sec. .14 sec. .19 sec. .22 sec. .37 sec. .52 sec. 1.00 sec. 2.20 sec.

.40 sec. .50 sec. .65 sec. .75 sec. .88 sec. 1.25 sec. 2.40 sec. 4.30 sec. -

20 gauge Bare wire

.45 sec.

14 gauge Bare wire

.50 sec.

-

a faster response time see GIC’s new “Faster Response Time” (Page 4)

diagram sm sheath materials

The sheath material gives the MgO insulation it’s protection from the environment, contamination and potential mechanical damage. There is no material that is appropriate for all applications; you must consider the process temperature, corrosiveness, mechanical strength, cost and intended service life when selecting the material.

  • 304ss (4) maximum temperature is 1650 deg. F (900 Deg. C), it is

most often used in low temperature processes and is the low-

e s t c o s t o

f th

e s t a i n l

e s s s t e e l s .

W i d e l y u s e

d in b

e v e r a g e , f o o d ,

chemical and other industries where mild corrosion resistance is needed. It is susceptible to carbide precipitation at tempera- tures of 900 to 1600 Deg. F (480 to 870 Deg. C).

  • 310ss (0) maximum temperature is 2100 Deg. F (900 Deg. C), it contains 25% Chromium and 20% Nickel. It’s corrosion resis- tance and mechanical strength is similar to 304SS but slightly better, has good heat resistance but not as ductile as the 304 series stainless steel.

maX in air

operaTing

maX conTinuous

maTeriaL

(of)

aTmosphere

TemperaTure (of)

304 Stainless

1900

ORNV

1650

310 Stainless

2550

ORNV

2100

316 Stainless

2500

ORNV

1700

INCONEL

2550

ONVb

2100

diagram mgo

recommended sheaTh maTeriaLs (mgo)

  • o

    = oxidizing

n = neutral

r = reducing v = vacuum

vb = very sensitive to sulfur corrosion

  • 316ss (6) maximum temperature is 1700 Deg. F (900 Deg.C), it has the best corrosion resistance of all the stainless steel grades. It is susceptible to carbide precipitation at temperatures of 900 to 1600 Deg. F (480 to 870 Deg. C). It is widely used in the chemical and food industry.

  • inconel 600 (I) maximum temperature is 2100 Deg. F (1175 Deg. C.) is the most predominately used sheath material due to it’s high temperature strength, resistance to chloride ion stress, corrosion resistance, oxidation resistance at elevated temperatures and it fairs well in nitriding environments. Inconel 600 must not be used in sulfur bearing environments.

  • Other sheath materials are available for special applications. Please consult the factory for your special request. For a complete list of sheath materials go to our website at www.gicsensors.com.

copper (C), epoxy glass sheath (T), to be used with Cooper Tipped sensors Tantalum (T), hastelloy X (H), 446 ss (X), monel (M), and others.

14

4949 Delemere Ave., Royal Oak, Michigan 48073 Phone (800) 876-4442 Fax (248) 280-0998

A9

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