Thermocouple Specifications
| TABLE 1 SHEATH & WIRE DIAMETER | ||||||||||||
| ARi SYMBOL | L | A | B | D | E | F | G | I | K | P | R | |
| SHEATH DIAMETER |
Inches | .020 | .040 | .062 | .125 | .188 | .250 | .313 | .375 | .500 | .625 | .750 |
| mm | .50 | 1.00 | 1.67 | 3.17 | 4.75 | 6.35 | 8.00 | 9.52 | 12.7 | 15.9 | 19.1 | |
| WIRE DIAMETER |
inches | .004 | .006 | .010 | .020 | .032 | .040 | .051 | .064 | .091 | .114 | .120 |
| mm | .10 | .15 | .25 | .50 | .85 | 1.00 | 1.45 | 1.63 | 2.31 | 2.90 | 3.05 | |
| MAX. LENGTH |
feet | 30 | 200 | 290 | 290 | 135 | 81 | 45 | 30 | 30 | 20 | 13 |
| meters | 9 | 61 | 88 | 88 | 41 | 25 | 14 | 9 | 9.1 | 6.1 | 4.0 | |
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TABLE 2 WIRE CALIBRATION (Special Limits of Error) |
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| ASTM E-230 Symbol |
ARi Symbol |
Similar Calibrations |
| K | KS | BS 1827, DIN 43710, NFE 18-001, JIS-C1602 |
| J | JS | BS 1829, NFE 18-001 |
| E | ES | --- |
| T | TS | BS 1828, DIN 43710, NFE 18-001, JIS-C1602 |
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TABLE 3 MEASURING JUNCTION SYMBOLS |
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| TABLE 4 SHEATH MATERIALS | ||||||
| SHEATH | ARi SYMBOL |
MELTING POINT |
USEABLE TEMP. IN AIR |
EQUIVALENT ANALYSIS |
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| ºF | ºC | ºF | ºC | |||
| AISI 347 ST/ST | F | 2550 | 1400 | 1650 | 900 | BS 3605 832Nb; DIN 4550; UNS S34700 |
| INCONEL 600 (3) | B | 2570 | 1410 | 2100 (1) | 1150 | BS 3074-NA14; DIN 4816; UNS NO6600 |
| AISI 304 ST/ST | A | 2550 | 1400 | 1650 (2) | 900 | BS 3605-801; DIN 4301; UNS S30400 |
| AISI 310 ST/ST | D | 2570 | 1410 | 2100 | 1150 | BS 3605-805; DIN 4878; UNS S31000 |
| AISI 316 ST/ST | C | 2550 | 1400 | 1650 | 900 | BS 3605-845; DIN 4401; (2-3% Mo); UNS S31600 |
| HASTELLOY X | V | 2470 | 1355 | 2200 | 1222 | Trademark of Cabot Corp. |
| (1)
Not recommended for use in sulfur atmosphere (2) Do not use in 800 to 1600ºF temperature range due to carbon intergranular precipitation (3) Trademark of International Nickel Corp. |
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| TIME CONSTANTS |
Some typical time constants (time for thermocouple temperature to reach 63.2% of a step change in gas or liquid temperature) for various sizes are listed for different media. |
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| SHEATH DIAMETER |
CONDITION A (seconds) |
CONDITION B (seconds) |
CONDITION C (seconds) |
CONDITION D (seconds) |
| 5/16" | 0.5 | 5.5 | 5.0 | 55.0 |
| 1/4" | 0.3 | 4.0 | 2.5 | 39.0 |
| 3/16" | 0.2 | 2.5 | 2.0 | 26.0 |
| 1/8" | 0.1 | 1.5 | 1.0 | 14.0 |
| 1/16" | 0.05 | 0.5 | 0.5 | 5.0 |
| 0.040" | 0.01 | 0.3 | 0.1 | 2.5 |
| Condition A: No. 7
hot junction in water moving at a velocity (Vo) of 1.5 m/sec.
(5 ft/second) Condition B: No. 8 hot junction in water moving at a velocity (Vo) of 1.5 m/sec. (5 ft/second) Condition C: No. 7 hot junction in air moving at a mass velocity (Go) of 29.3 Kg/sec. m2 (6 lbs/sec. ft.2) Condition D: No. 8 hot junction in air moving at a mass velocity (Go) of 29.3 Kg/sec. m2 (6 lbs/sec. ft.2) For time constants (r) at other velocities (V) or mass velocities (G) use the following equations: |
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The results of these equations will be affected by using liquids other than water and gases other than air. However, the effect is small and can be neglected for many applications. | |||
| THERMOCOUPLE SPECIFICATIONS | |
| Insulation Material | Symbol "N" 99.4% minimum high purity MgO meeting requirements of ASTM E-585 and E-608. Impurities are minimized to yield maximum EMF stability and minimum drift problems. |
| Lead Wire Length "L" | 16 inch (40cm) long lead length is normally supplied. If longer lengths are required, please designate in part number. |
| Insulation Resistance | 100 meg-ohms or more at 500 VDC for lengths of 15 meters (50 feet) or less for 1.67 to 8.0mm (1/16" to 5/16") diameter. 10 meg-ohms or more at 1 1/2 VDC for lengths of 15 meters (50 feet) or less for 1.0 and .63mm (0.04" and 0.025") diameters. This measurement is made prior to fabrication of the hot junction. |
| Insulation Bend Resistance | Minimum insulation resistance, after bending around a mandrel whose diameter is 4 times, the sheath diameter, to be 2.5 meg-ohms at 1 1/2 VDC. |
| High Temperature Insulation Resistance | All AerOpak® thermocouple lengths of 61cm (24") or less will have a minimum insulation resistance of 10,000 ohms or more at 1 1/2 VDC at 1000ºC (1800ºF.) |
| Availability | 2 wire (1 T/C circuit) sheath
diameters: 0.50 to 19.1mm (0.020" to 0.750") 4 wire (2 T/C circuits) sheath diameters: 3.17 to 19.1mm (0.125" to 0.750") All thermocouples are available with exposed, grounded, or un-grounded measuring junctions. |
| Specifications | Thermocouples can be made to meet specific customer requirements, or to specifications such as MIL-T-23234A, RDT C7-6T, ASTM E-235, ASTM E-585 or E-608 |
| Pressure Rating | AerOpak® thermocouples using number 8 or 9 measuring junctions are pressure tight to 3500 Kg/cm2 (50,000 psi) at temperatures up to 649ºC (1200ºF). AerOpak® thermocouples using number 7 measuring junctions are pressure tight to 350 Kg/cm2 (50,000 psi) if a seal is used at the cold end. |