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| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Temperature limits | | Application examples | | | | | | PROFILE Mineral-insulated thermocouples correspond in form and design to the current DIN / IEC rules respectively are quite close. The thermocouple conductors are embedded in a closely compacted, inert mineral powder and surrounded by a metal sheath to form a hermetically sealed assembly. The sheath functions as a useful protective cover in many situations. They are applied in locations where fast response, reduced space and or vibration resistance is a need. They can be furnished with a fixed cable or with a special plug which allows rapid fitting or exchange. TECHNICAL DATA_ Meets DIN IEC 65 B (CO) 76 Sheath - Stainless steel SS 321 (1.4541) - Inconel 600, 2.4816 THERMOCOUPLE Type K to IEC 584 Type L to IEC 584 Type J to DIN 43710 - Single and duplex sensor - Measuring junction isolated and grounded Isolation resistance 1000 Mfi at room temperature At higher temperatures as also with smaller diameter the resistance is reduced. | | | | | | | | | | | | | | | | | | Element | Sheath 1.4541 | Sheath 2.4816 | | | | Type K | max. 800 °C | max. 1100 °C | | | | Type L | max 800 °C | | | | | Type J | max 800 °C | | | | | | | | | | | | | | | | | | | | | | 1.4541 | 2.4816 | | | | Chemical engineering | Reaction vessels | | | | Petro chemistry | Plastand fibre | | | | Food and Beverage | Pulp and paper | | | | Thermprocess | Boiler | | | | REACTION TIME | | | | | | | | | | | | | | | | | Temperature at the cable junction With standard extension lead +70 °C In general 200 °C APPLICATION HINTS The above mentioned max. temperatures are valid for clean air only. At higher temperatures especially with cyclic charges the thickness of the sheath decreases due to tindering. Agressive parts of the measuring medium attack the sheath material. Especially with sensors with small diameter life time decreases tremendeously at higher operating temperatures. | | | | | | | | | | Reaction time in [s] water at 0,2 m/s Air at 2,0 m/s | | | | | | Measuring junction isolated | | | | | | | | | | | | | | | | | | | | | | | | 0 [mm] | t0,5 | t0,9 | t0,5 | t0,9 | | | | 0,5 | 0,06 | 0,13 | 1,8 | 5,5 | | | | 1,0 | 0,15 | 0,5 | 3 | 10 | | | | 1,5 | 0,21 | 0,6 | 8 | 25 | | | | 3,0 | 1,2 | 2,9 | 23 | 80 | | | | 4,5 | 2,5 | 5,9 | 37 | 120 | | | | 6,0 | 4 | 9,6 | 60 | 200 | | | | Measuring junction grounded | | | | 0,5 | 0,03 | 0,1 | 1,8 | 6 | | | | 1,0 | 0,06 | 0,18 | 3 | 10 | | | | 1,5 | 0,13 | 0,4 | 8 | 25 | | | | 3,0 | 0,22 | 0,75 | 23 | 80 | | | | 4,5 | 0,45 | 1,6 | 33 | 110 | | | | 6,0 | 0,55 | 2,6 | 55 | 185 | | | | | | | | | | | | | | | | | | | | | | | | | | | | Measuring medium | Max. temperature [°C] | | | | | 1.4541 | 2.4816 | | | | Air | approx. 800 | approx. 1100 | | | | Carbon dioxide | approx. 650 | approx. 500 | | | | Petrol | approx. 100 | Not recommended | | | | Benzene | approx. 100 | | | | Boric acid | approx. 100 | | | | Buthyl alcohol | approx. 100 | | | | Phosphoric acid 50% | approx. 100 | | | | Nitric acid | approx. 100 | | | | Sodium, liquid | Not recommended | approx. 750 | | | | Air, with sulfur | approx. 550 | | | | Water, not chlorinated | approx. 590 | | | | | | | | | | | | | | | | | | Special remarks M.I. thermocouples can be bent at a radius 5 times of sheath diameter. Because of the inflexible attachement between sheath and thermoconductors at higer operating temperatures intense mechanical strength is applied to the thermoconductors. This leads to increased drift at extended operating time. | | | | | | | | | | (Not subject for completeness) | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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