Mineral Insulated Cables (MI)



The growing demand throughout the world for precision, reliability, and safety in the field of temperature-measurement and regulation techniques, which covers everything from a simple furnace to nuclear power plants; this has led to the increasing substitution of conventional cables by Mineral Insulated Cables.
Mineral Insulated metal sheathed cables are a proven choice in industries it comprises a metal sheath in which thermoelectric conductors or copper conductors are embedded in highly compressed MgO insulation. The metal other sheath protects the inner wire (i.e. thermocouple conductor) against contamination. Metal sheath makes it moisture proof, weldable, compact, and mechanically strong. Another distinct advantages, especially in thermocouple cable are, it allows, fabrication of thermocouples in small diameters.

The thermocouples, manufactured from MI thermocouple cables are flexible in design and can penetrate to odd location where ordinary thermocouple cannot approach. The small mass and higher thermal conductivity enables fast thermal response. Is general, the standard features and advantages of MIMS cables are

  • High Insulation Resistance Conductor / Sheath and Conductor / Conductor.
  • Long Life.
  • Easy Installation
  • Mechanical Strength
  • Safety
  • Rapid Response
  • Dielectric Strength
  • Radiation Resistance
  • Corrosion and Scaling Resistance
  • Long Lengths
  • Small Cable Diamete

Manufacturing Process

MIMS Cables are manufactured by using a higher diameter tubes and conductors. The conductors are inserted into metal pipe. The conductors are properly spaced in the pipe by using crushable Mgo blocks. These Mgo blocks provide insulation between the conductors as well as with the wall. Also these blocks maintain the geometry, i.e. the position of conductors. Processing of MIMS cables includes:

  • Cleaning of tubes
  • Insertion of conductor into the bocks
  • Host filling (I,e, insertion of conductors along with the blocks into the pipe)
  • Swaging (this operation crush the MgO blocks)
  • Drawing (The diameter is reduced by successive drawing which also ensures compact powder around the conductors)
  • Inter pass annealing (Various annealing are required to achieve the metal properties back, which are disturbed in drawing process. This annealing is conducted in controlled environment to retain the chemical properties of the sheath material)
  • Pickling and finishing

Techno offers wide range of MI cables for the production of thermocouples and RTD assembly. The standard OD of cables are 1.6 mm,3mm,4.5mm,6mm and 8mm. They are available with outer sheath of SS304, SS 316l, Inconel 600, Incolloy 800, SS310 and SS 321.

Dimensional Derail

Sheath OD*

in mm

No. of

conductors

Wall thickness

in mm

Conductor

dia in mm

Nominal coil

length
in mtrs.

1.0 2 0.13 0.15 100
1.6 2 0.21 0.30 200
3.0 2 0.35 0.50 90
3.0 4 0.35 0.48 90
4.5 2 0.55 0.70 80
4.5 4 0.56 0.68 80
6.0 2 0.71 0.95 45
6.0 4 0.71 0.90 45
8.0 2 0.95 1.20 20
8.0 4 0.93 1.15 20
9.5 2 1.21 1.40 15
9.5 4 1.15 1.38 15
*Any intermediate OD available on request

Product code MI thermocouple cables

Part no = SD-TC-MOC Where SD = sheath dia of thermocouple in mm, e.g. 1.6, 3.0, 4.5, 6.0, 8.0, 9.5 TC=type of thermocouple e.g. K, J, T, E, etc. MOC = MOC of sheath material e.g. INC600, SS310, S316, SS304, SS321, INC800 etc. For e.g. 3KSS316 is K type MI cable, simplex, with 3 mm dia, and SS316 sheath material in case of Duplex MI cables, letter for TC is mentioned for 2 times for e. g. 3KKSS316 is K type MI cable, duplex, with SS 316 Sheath material

Product code for copper conductor type MI Cable

Part no. = SD-Nos.of C-MOC Where SD = sheath dia of thermocouple in mm, e. g. 1.6, 3.0, 4.5, 6.0, 8.0, 10.0, No. of C = no. of copper conductors, e. g. 1,2,3,4,6 etc. MOC = MOC of sheath material e. g. SS316, SS304, Inc600, Copper etc. For e. g. 6-6C-SS316 is 6 nos. of copper conductor with Sheath MOC of SS 316

Note :
 we also offer conductors of copper alloys (for various applications like R/S compensating conductors etc.)

Q. C. Testing

  • Following Tests are conducted on each MI Cable
  • Insulation Test
  • Dimension Check
  • Accuracy Test ( in case of Thermocouple cable)
  • Sheath puncture Test
  • Inspection Test



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With over 3000 Plus of clients in almost all possible applications of Temperature Measurements in every industry like Power, Chemical, Process, Pharmaceutical, Cement, Metal, Nuclear etc. we have dedicated all our resources to deliver cost effective, reliable and long-lasting solutions to our customers everywhere.

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