Mineral insulated thermocouple

with bare ends termination

"PTMTC"  range


Mineral insulated thermocouples are widely used for temperature measurement in many applications. To their essential characteristics -sensing element, insulation, protecting sheath material and connection- those thermocouples add unique properties such as bending possibilities (to suit any environment) and a wide range of dimensions (from miniaturization to great lengths). The bare ends termination offers flexible and direct connection possibilities.

  • Most common thermocouple types: K, J, T, N, S
  • Other thermocouples on request

Temperature range

From -200°C to + 1700°C. More information...

The environment and the temperatures to be measured are the two main criteria for selecting the diameter and material of the mineral sheath.

Temperature resistance of the main mineral insulated cables in neutral atmosphere:

- 304L & 316L SS: + 700°C
- 310 (25/20) SS : + 1100°C
- Inconel 600 : + 1150°C

Recommended usage temperature depending on thermocouple type and MI cable diameter:

 J

 T

 K and N

   0,5 - 1 mm

 260

 260

 700

   1,5 mm

 440

 260

 920

   3  mm

 520

 315

 1070

   6  mm

 720

 370

 1150

 

Temperature resistance of the extension cable :

  • PVC: -20°C to +105°C
  • Silicon: -50°C to +200°C
  • Teflon: -50°C to +260°C
  • Glass fiber: +400°C
  • Ceramic fiber: +750°C

Colour codes and tolerances comply with the NF EN 60-584-3 standard


MI cable mechanical data 

Bending diameter must be  ³ 5 x sheath diameter

          Compact mineral insulation (magnesium oxide) allows perfect insulation of the wires whichever shape is given to the thermocouple.


Accuracy

Accuracy depends on:
- Thermocouple wire tolerances as per IEC 584 European standard. More information...

Response time
to reach x% of the temperature scale interval (in seconds)

 Ø in mm

 63%

90% 

    <  0,5

 0.4

 0.7

     1

 0.5

 0.8

     1,5

 0.8

 1

     2

 1

1.5 

     3

 1.2

2.1 

     4,5

 2.3

 4.3

     6

 3.5

     8

 8.1

 18

Test carried out in compliance with UTE C46-201standard, on a type K thermocouple with ungrounded hot junction, inconel 600 sheath (indicative data)

Applicable standards

  • IEC 584
  • UTE 46201
    Whenever requested by specific applications, other applicable standards are also complied with in accordance with our EMS (Specific calibration requirements) procedure.

Certification

Mineral insulated thermocouples may be used in potentially explosive atmospheres provided that the requirements of the 94/9/CE  ATEX  European Directive and our EC-type examination certificate are complied with. More information.


Most common dimensions:

     - MI cable diameter : 0.5 - 1 - 1.5 - 2 - 3 - 4.5 - 6 - 8 mm
     - MI cable length "L" : as per customer request, depending on diameter and material
     - Extension cable length "Lp" : < 100 meters

sensing element :
- Standard:

  type K, J, T, N, S simple or dual thermocouple

- Specific:

  type E, B, R, C simple or dual thermocouple

sheath :


     - standard:

       304L, 316L, 321, 310 stainless steel, Inconel 600

     - specific:

       Inconel 601, Incoloy 800, Hasteloy X, AISI 446, Tantale, platinum...

hot junction :
insulation :
- standard: MgO (magnesium oxide)
- high purity: pure alumina

transition :


- undismantable junction box,
  Ø 3 to 10mm

- strain relief spring

cable :


Extension and compensating cables comply with the IEC 584-3 standard.

 

options :
     • Fixed fitting
     • Compression fitting with Teflon or metallic insert

 

International colour code for compensating cable : 

 symbol

 +

 -

 sheath

 JC

 black

 white

 black

 KC

 green

 white

 green

 TC

 brown

 white

 brown

 NC

 pink

 white

 pink

 SC / RC

 orange

 white

 orange

 BC

 grey

 white

 grey

IEC 584-3 standard

Recommendations :

  • Immersed length : 10 x Ø
  • Ohm/4-20mA transmitters may be used with such thermocouples

Setting up:

Fixed or sliding compression fitting with Teflon or metallic insert.