Technical Characteristics and FailSafe Reliability
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Single-Device SIL3 Integrity: The FTL81 is engineered for the highest level of risk reduction, meeting SIL3 standards (1oo1 architecture). This is achieved through internal redundancy and continuous self-monitoring of the tuning fork and electronics, ensuring any internal fault is immediately detected.
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Long-Term Maintenance Efficiency: Thanks to its intelligent diagnostics, the FTL81 supports a proof test interval of up to 12 years. Verification can be performed remotely or at the press of a button, significantly lowering the total cost of ownership and increasing plant uptime.
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Comprehensive Fork Monitoring: The device does not just check for the presence of liquid; it actively monitors the tuning fork for mechanical damage, corrosion, blocking, or heavy coating. This ensures the safety function is never compromised by the process conditions.
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4-20mA NAMUR Interface: Using the NAMUR NE 06/NE 43 standard, the FTL81 communicates its status (covered, free, or fault) via a current signal. This allows for simple integration into a safety PLC or the dedicated Nivotester FailSafe FTL825 switching unit for automated safety loops.
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Second Line of Defense: The FTL81 includes a gas-tight feedthrough as standard. This secondary containment barrier prevents hazardous process media from leaking into the electronics housing or the environment if the primary sensor diaphragm is breached.
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Extreme Process Versatility: Constructed from 316L or Alloy C, the sensor can handle extreme temperatures from -60 to +280°C and high-pressure environments up to 100 bar.
Technical Specification Matrix
| Feature | Technical Details |
| Measuring Principle | Vibronic (Tuning Fork) |
| Safety Integrity Level | SIL3 (Single device 1oo1) |
| Sensor Design | Extension pipe version (up to 3m / 9.8ft) |
| Process Temperature | -60 to +280°C (-76 to +540°F) |
| Process Pressure | -1 to +100 bar (-14.5 to +1,450 psi) |
| Output Signal | 4-20mA (NAMUR NE 06 / NE 43) |
| Safety & Compliance | SIL3, WHG, ATEX, IECEx, Marine |
Primary Applications
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Deep Tank Overfill Protection: Providing a SIL3-rated high-level alarm in large storage tanks for volatile or toxic chemicals.
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Sumps and Underground Reservoirs: Using the extension pipe to detect liquid levels at specific depths where standard sensors cannot reach.
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Safety-Critical Chemical Reactors: Monitoring levels in high-pressure, high-temperature reactors where the media is highly aggressive.
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Environmental Protection: Serving as a “FailSafe” barrier for hazardous liquids to comply with strict WHG regulations and prevent spills.
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Remote Safety Nodes: Ideal for installations where frequent manual proof testing is difficult or dangerous, utilizing the 12-year testing interval.
