Optimized Multipoint (OMP)
The optimized multi-point thermocouple (OMP) is made with an ungrounded (aka. isolated) junction design, though it is easily adapted to allow grounded junctions. Multiple measuring points can be arranged along the length of the probe with great accuracy.
The following information describes the standard configuration. Other configurations can be made upon request.
SPECIFICATIONS:
- Compacted MgO Insulation 99.4% minimum purity. Insulation Resistance: 500 megohms at 500 vdc minimum.
- Thermocouple Calibration Types Offered:
- Type “K” Standard or Special Limits of Error (Class I & II) Type “J” Standard Limits of Error (Class II) – (Special Order)
- Standard Sheath Materials Offered (others offered upon request):
- SST 316, SST 304, Inconel™ 600 (nickel alloy 600)
Design Rules:
- Number of Points: up to 19 points (depends on OD of cable, see table below)
- Minimum distance between measuring points (junctions): 1.0” (25.4mm)
- Point Location Tolerance: O.D. of cable, or +/- .3% of length, whichever is greater.
- Positive wire is the inner wire: “K” Positive. Negative wires are placed as the outer wires: “K” Negative.
- Minimum Bend Radius = 10 times the sheath diameter.
- Transported straight (if possible) or in a 24’’ or 33’’ diameter coil.
Standard Outside Diameter, Points and Maximum Lengths
| O.D. | Tolerance | Max # of Points | Normal Length | Max Length | *Notes |
|---|---|---|---|---|---|
| .313’’ | +/- .003’’ (7.95mm) | Up to 19 | 250 feet | 500 feet | Type K Max 2100°F |
| .250’’ | +/- .002” (6.35mm) | Up to 13 | 400 feet | 800 feet | Type K Max 2100°F |
| .188’’ | +/- .002’’ (4.78mm) | Up to 10 | 700 feet | 1400 feet | Type K Max 2100°F |
| .125’’ | +/- .002’’ (3.18mm) | Up to 7 | 1600 feet | 3200 feet | Type K Max 1960°F |
*Max temperatures per ASTM E-608, sheath material will determine max useable temperature.
Dimensional Information: Wall Thickness & Wire Diameters
| Number Of Thermocouple Measuring Points | Wall Thickness (% of Diameter) |
Outer Wire Diameter (% of Diameter) |
Inner Wire Diameter (% of Diameter) |
|---|---|---|---|
| 2 – 4 | 11.8% | 11.0% | 15.5% |
| 5 – 7 | 11.8% | 8.5% | 11.7% |
| 8 – 10 | 11.8% | 8.0% | 10.3% |
| 11 – 13 | 11.8% | 7. 6% | 11.4% |
| 14 – 16 | 11.8% | 7.2% | 12.1% |
| 17 – 19 | 7.8% | 7.3% | 14.3% |