The thermocouple compensation cables can also be termed as instrumentation cables, since they are used for process temperature measurement. The construction is similar to pair instrumentation cable but the conductor material is different. Thermocouples are used in processes to sense temperature and is connected to the pyrometers for indication and control. The thermocouple and pyrometer are electrically conducted by thermocouple extension cables / thermocouple compensating cables. The conductors used for these thermocouple cables are required to have similar thermo-electric (emf) properties as that of the thermocouple used for sensing the temperature.
Our mill mainly manufacture type KX,,EX,JX,TX,SC/RC,KCA,KCB compensating wire for thermocouple, and they are used in temperature measurement instruments and cables. Our thermocouple compensating products are all made abiding by GB/T 4990-2010 ‘Alloy wires of extension and compensating cables for thermocouples’ (Chinese National Standard), and also IEC584-3 ‘Thermocouple part 3-compensating wire’ (International standard).
The representing of the comp. wire: thermocouple code+C/X , e.g. SC, KX
X: Short for extension, means that the compensation wire’s alloy is as the same as the the alloy of the thermocouple
C: Short for compensation, means that the compensation wire’s alloy has similar characters with the thermocouple’s alloy in a certain temperature range.
| Thermocouple Code |
Comp. Type |
Comp. Wire Name |
Positive |
Negative |
| Name |
Code |
Name |
Code |
| S |
SC |
copper-constantan 0.6 |
copper |
SPC |
constantan 0.6 |
SNC |
| R |
RC |
copper-constantan 0.6 |
copper |
RPC |
constantan 0.6 |
RNC |
| K |
KCA |
Iron-constantan22 |
Iron |
KPCA |
constantan22 |
KNCA |
| K |
KCB |
copper-constantan 40 |
copper |
KPCB |
constantan 40 |
KNCB |
| K |
KX |
Chromel10-NiSi3 |
Chromel10 |
KPX |
NiSi3 |
KNX |
| N |
NC |
Iron-constantan 18 |
Iron |
NPC |
constantan 18 |
NNC |
| N |
NX |
NiCr14Si-NiSi4Mg |
NiCr14Si |
NPX |
NiSi4Mg |
NNX |
| E |
EX |
NiCr10-Constantan45 |
NiCr10 |
EPX |
Constantan45 |
ENX |
| J |
JX |
Iron-constantan 45 |
Iron |
JPX |
constantan 45 |
JNX |
| T |
TX |
copper-constantan 45 |
copper |
TPX |
constantan 45 |
TNX |
1. Chemical Composition
| Material |
Chemical composition (%) |
| Ni |
Cr |
Si |
Mn |
Al |
| KP(Chromel) |
90 |
10 |
|
|
|
| KN(Alumel) |
95 |
|
1-2 |
0.5-1.5 |
1-1.5 |
2. Physical properties and Mechnical properties
| Material |
Density(g/cm3) |
Melting point(ºC) |
Tensile Strength(Mpa) |
Volume resistivity(μΩ.cm) |
Elongation rate (%) |
| KP(Chromel) |
8.5 |
1427 |
>490 |
70.6(20ºC) |
>10 |
| KN(Alumel) |
8.6 |
1399 |
>390 |
29.4(20ºC) |
>15 |
3. EMF Value range at different temperature
| Material |
EMF value Vs Pt(μV) |
| 100ºC |
200ºC |
300ºC |
400ºC |
500ºC |
600ºC |
| KP(Chromel) |
2816~2896 |
5938~6018 |
9298~9378 |
12729~12821 |
16156~16266 |
19532~19676 |
| KN(Alumel) |
1218~1262 |
2140~2180 |
2849~2893 |
3600~3644 |
4403~4463 |
5271~5331 |
| EMF value Vs Pt(μV) |
| 700ºC |
800ºC |
900ºC |
1000ºC |
1100ºC |
| 22845~22999 |
26064~26246 |
29223~29411 |
32313~32525 |
35336~35548 |
| 6167~6247 |
7080~7160 |
7959~8059 |
8807~8907 |
9617~9737 |
Type K Extension Cable Chromel / Alumel Material FEP insulation
Specifications
1.Style:Extension Wire
2.Thermocouple copper wire
Thermocouple copper wire Classification
1. Thermocouple level (high temperature level). This type of thermocouple wire is mainly suitable for thermocouple type K, J, E, T, N and L and other high temperature detection instrument, temperature sensor, etc.
2. Compensating wire level (low temperature level). This type of thermocouple wire is mainly suitable for compensating cable and extension wire of various thermocouples of type S, R, B, K, E, J, T, N and L, heating cable, control cable and so on.
Thermocouple variety and index
| Thermocouple Variety and Index |
| Variety |
Type |
Measurement Range(°C) |
| NiCr-NiSi |
K |
-200-1300 |
| NiCr-CuNi |
E |
-200-900 |
| Fe-CuNi |
J |
-40-750 |
| Cu-CuNi |
T |
-200-350 |
| NiCrSi-NiSi |
N |
-200-1300 |
| NiCr-AuFe0.07 |
NiCr-AuFe0.07 |
-270-0 |
3 . Dimensions and Tolerance of Fiberglass Insulated Thermocouple Wire
Dimensions / Tolerance mm ) : 4.0+-0.25
Color code & initial calibration tolerances for thermocouple wire:
| Thermocouple Type |
ANSI Color Code |
Initial Calibration Tolerances |
| Wire Alloys |
Calibration |
+/-
Conductor |
Jacket |
Temperature Range |
Standard
Limits |
Special
Limits |
CHROMEL(+) vs.
ALUMEL(-) |
K |
Yellow/Red |
Brown |
-200°C to -110°C
-110°C to 0°C
0°C to +285°C
285°C to +1250°C |
± 2%
±2.2°C
±2.2°C
± .75% |
±1.1°C
± .4% |
Color Code & Initial Calibration Tolerance for Extension Wire:
| Extension type |
ANSI Color Code |
Initial Calibration Tolerances |
| Wire Alloys |
Calibration |
+/-
Conductor |
Jacket |
Temperature Range |
Standard
Limits |
Special
Limits |
| Iron (+) vs. Constantan(-) |
JX |
White/Red |
Black |
0°C to +200°C |
±2.2°C |
±1.1°C |
| CHROMEL (+) vs. ALUMEL (-) |
KX |
Yellow/Red |
Yellow |
0°C to +200°C |
±2.2°C |
±1.1°C |
| Copper(+) vs. Constantan(-) |
TX |
Blue/Red |
Blue |
-60°C to +100°C |
±1.1°C |
± .5°C |
| CHROMEL(+) vs. Constantan(-) |
EX |
Purple/Red |
Purple |
0°C to +200°C |
±1.7°C |
±1.1°C |
PVC-PVC Physical Properties:
| Characteristics |
Insulation |
Jacket |
| Abrasion Resistance |
Good |
Good |
| Cut Through Resistance |
Good |
Good |
| Moisture Resistance |
Excellent |
Excellent |
| Solder Iron Resistance |
Poor |
Poor |
| Service Temperature |
105ºC continuous
150ºC single |
105ºC continuous
150ºC single |
| Flame Test |
Self-extinguishing |
Self-extinguishing |
