Multipoint sheathed probes measure temperature at selected depths in towers, reaction tanks and process equipment. Single-stem multipoint and multiple-probe multipoint thermocouple constructions are available. A related thermocouple and Pt100 construction provides 3-point, 6-point and 12-point diameter selections for fertilizer-industry towers and tanks.
| Sensor type | Element | Sheath material | Temperature range | Accuracy class | Configuration availability |
|---|---|---|---|---|---|
| Platinum-10% rhodium / platinum | S | GH30 alloy | 0-1200°C | I or II | Both multipoint constructions |
| Nickel-chromium / nickel-silicon | K | 0-1100°C | |||
| 06Cr18Ni11Ti | 0-800°C | ||||
| Nickel-chromium / copper-nickel | E | 0-700°C | |||
| Iron / copper-nickel | J | 0-600°C | |||
| Copper / copper-nickel | T | -200-300°C | 3-point, 6-point and 12-point construction | ||
| Platinum RTD | Pt100 | -200-500°C | B |
| Thermocouple construction | Maximum measuring points | Maximum length |
|---|---|---|
| Single-stem multipoint | 6 | 8m |
| Multiple-probe multipoint | 30 | 150m |
The multiple-probe construction can use sheathed elements as small as 0.5mm. Ordinary water-resistant, flameproof and stainless steel flameproof heads are available. Mounting options include no fixed device, M33x2 or M27x2 threads, a 70mm sliding flange or a fixed flange specified for the application.
| Measuring points | Sheath diameter options |
|---|---|
| 3 | 3mm, 4mm, 5mm, 6mm or 8mm |
| 6 | 3mm, 4mm, 5mm or 6mm |
| 12 | 3mm |
For the tower-and-tank construction, sheath diameters below 5mm can support specified depths exceeding 30m. The installation requires an outer protective tube supplied for the application; without it, use is limited to atmospheric-pressure, non-corrosive media. Two output connections are provided per measuring point and arranged by point sequence. A two-wire RTD output can use two terminal connections at one end and one at the other for a three-wire instrument connection.
Insulated and grounded thermocouple junctions are available. Grounded junctions are not recommended for flameproof versions. Flameproof marking options include Ex d IIB T1-T5 and Ex d IIC T1-T6.
| Parameter | Tower-and-tank multipoint specification |
|---|---|
| Thermocouple insulation at ambient temperature | ≥1000MΩ |
| Thermocouple insulation at high temperature | ≥5MΩ |
| Platinum RTD insulation at ambient temperature | ≥100MΩ |
| Flameproof thermocouple and RTD ingress protection | Up to IP65 |
